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Sample records for icy moons orbiter

  1. The Jupiter Icy Moons Orbiter reference trajectory

    NASA Technical Reports Server (NTRS)

    Whiffen, Gregory J.; Lam, Try

    2006-01-01

    The proposed NASA Jupiter Icy Moons Orbiter (JIMO) mission would have used a single spacecraft to orbit Callisto, Ganymede, and Europa in succession. The enormous Delta-Velocity required for this mission (nearly [25 km/s]) would necessitate the use of very high efficiency electric propulsion. The trajectory created for the proposed baseline JIMO mission may be the most complex trajectory ever designed. This paper describes the current reference trajectory in detail and describes the processes that were used to construct it.

  2. A Power Conversion Concept for the Jupiter Icy Moons Orbiter

    NASA Technical Reports Server (NTRS)

    Mason, Lee S.

    2003-01-01

    The Jupiter Icy Moons Orbiter (JIMO) is a bold new mission under development by the Office of Space Science at NASA Headquarters. ITMO is examining the potential of Nuclear Electric Propulsion (NEP) technology to efficiently deliver scientific payloads to three Jovian moons: Callisto, Ganymede, and Europa. A critical element of the NEP vehicle is the reactor power system, consisting of the nuclear reactor, power conversion, heat rejection, and power management and distribution (PMAD). The emphasis of this paper is on the non-nuclear elements of the reactor power system.

  3. Radio Science Concepts and Approaches for Jupiter Icy Moons Orbiter

    NASA Technical Reports Server (NTRS)

    Anderson, J. D.; Asmar, S. W.; Castillo, J. C.; Folkner, W. M.; Konopliv, A. S.; Marouf, E. A.; Rappaport, N. J.; Schubert, G.; Spilker, T. R.; Tyler, G. L.

    2003-01-01

    Radio Science experiments have been conducted on most deep space missions leading to numerous scientific discoveries. A set of concepts and approaches are proposed for the Jupiter Icy Moons Orbiter (JIMO) to apply Radio Science tools to investigate the interior structures of the Galilean Satellites and address key questions on their thermal and dynamical evolution. Measurements are identified that utilize the spacecraft's telecommunication system. Additional instruments can augment these measurements in order to leverage observational synergies. Experiments are also offered for the purpose of investigating the atmospheres and surfaces of the satellites.

  4. Jupiter Icy Moons Orbiter (JIMO) Electrical Systems Testbed

    NASA Technical Reports Server (NTRS)

    Trapp, Scott J.

    2004-01-01

    The Jupiter Icy Moons Orbiter (JIMO) mission will send a spacecraft to explore three of Jupiter s moons (Callisto, Ganymede, and Europa), all of which show evidence of containing vast subterranean oceans beneath their icy surfaces. The evidence of these oceans was discovered by Galileo, and the moons are believed to have the three essential ingredients for life: water, energy, and the necessary chemical elements. Galileo has shown that melted water on Europa has been in contact with the surface of the moon in geologically recent times, and may still lie relatively close to the surface. This project will also introduce a revolutionary new form of electric propulsion powered by a nuclear fission reactor. This electric propulsion is called ion propulsion. It was used on a previous mission called Deep Space 1, proving that ion propulsion works for interplanetary travel. Since JIMO will be traveling farther from the sun, solar power will be difficult to supply the electric energy demanded by the mission. Therefore a nuclear reactor and a thermo-electric converter system will be necessary. Besides making the trip to three of Jupiter's moons - one after the other - a realistic possibility, this new form of power and propulsion opens up the rest of the outer solar system for future exploration. JIMO will fulfill its goals by exploring Europa first, with subsequent trips to the moons Callisto and Ganymede in order to provide comparisons key to understanding the evolution of all three. In order to ensure the stability and proper preparation of the electrical system on JIMO, the High Power AC Power Management and Distribution (PMAD) Test Bed is being developed. The testing on.this AC PMAD will consist of electrical performance verification of candidate power system components. Examples of these components are: high power AC switchgear, high power ACDC converters, AC power distribution units, DC power distribution units, etc. Throughout the course of the summer the over

  5. Forum on Concepts and Approaches for Jupiter Icy Moons Orbiter

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The papers presented at this conference primarily discuss instruments and techniques for conducting science on Jupiter's icy moons, and geologic processes on the moons themselves. Remote sensing of satellites, cratering on satellites, and ice on the surface of Europa are given particular attention. Some papers discuss Jupiter's atmosphere, or exobiology.

  6. A Power Conversion Concept for the Jupiter Icy Moons Orbiter

    NASA Technical Reports Server (NTRS)

    Mason, Lee S.

    2003-01-01

    The Jupiter Icy Moons Orbiter (JIMO) mission is currently under study by the Office of Space Science under the Project Prometheus Program. JIMO is examining the use of Nuclear Electric Propulsion (NEP) to carry scientific payloads to three Jovian moons. A potential power system concept includes dual 100 kWe Brayton converters, a deployable pumped loop heat rejection subsystem, and a 400 Vac Power Management and Distribution (PMAD) bus. Many trades were performed in aniving at this candidate power system concept. System-level studies examined design and off-design operating modes, determined startup requirements, evaluated subsystem redundancy options, and quantified the mass and radiator area of reactor power systems from 20 to 200 kWe. In the Brayton converter subsystem, studies were performed to investigate converter packaging options, and assess the induced torque effects on spacecraft dynamics due to rotating machinery. In the heat rejection subsystem, design trades were conducted on heat transport approaches, material and fluid options, and deployed radiator geometries. In the PMAD subsystem, the overall electrical architecture was defined and trade studies examined distribution approaches, voltage levels, and cabling options.

  7. Jupiter Icy Moons Tidal Signatures and Ocean Mapping from Orbit

    NASA Technical Reports Server (NTRS)

    Wu, X.; Bar-Server, Y. E.; Folkner, W. M.; Williams, J. G.; Zumberge, J. F.

    2003-01-01

    Following the Galileo spacecraft encounters with Europa, Ganymede, and Callisto, evidence emerged suggesting that these Galilean moons of Jupiter may have liquid oceans underneath their icy shells. Detection of the oceans on one or all three moons will have profound implications on probability of life beyond the Earth. The icy satellites also have tidal environments that are among the strongest in the solar system. The leading time-varying tidal forcing term on the surface of Europa is at least 9 times larger than those on the inner planets. Tidal forcing on the surfaces of Ganymede and Callisto are about 10% and 7%, respectively, of that on Europa. Since a planetary body with internal fluid deforms more than an otherwise solid body, tidal measurements offer exciting opportunities to detect the oceans.

  8. Numerical investigation of mapping orbits about Jupiter's icy moons

    NASA Technical Reports Server (NTRS)

    Aiello, John

    2005-01-01

    A proposed mission that would orbit Callisto, Ganymede, and Europa will require low altitude, high inclination orbits for gravity and surface mapping. This paper explores the dynamics of these orbits by direct propagation against an ephemeris model. Initial conditions within the context of a mapping mission's likely requirements are considered. The results complement the analytical studies and reveal additional dependencies.

  9. Jupiter Icy Moons Orbiter (JIMO): An Element of the Prometheus Program

    NASA Astrophysics Data System (ADS)

    2004-10-01

    The Prometheus Program s Jupiter Icy Moons Orbiter (JIMO) Project is developing a revolutionary nuclear electric propulsion space system that would return scientific data from the icy Galilean satellites, Callisto, Ganymede, and Europa. This space system could also be used for future solar system exploration missions. Several major achievements occurred during Fiscal Year 2004 (FY 04). These include the addition of Department of Energy Naval Reactors (DOENR) and Northrop Grumman Space Technology (NGST) to the JIMO team, completion of the Science Definition Team s final report, generation of the Government and industry team trade studies and conceptual designs, and numerous technology demonstrations. The sections that follow detail these accomplishments.

  10. Electric Propulsion Technology Development for the Jupiter Icy Moons Orbiter Project

    NASA Technical Reports Server (NTRS)

    2004-01-01

    During 2004, the Jupiter Icy Moons Orbiter project, a part of NASA's Project Prometheus, continued efforts to develop electric propulsion technologies. These technologies addressed the challenges of propelling a spacecraft to several moons of Jupiter. Specific challenges include high power, high specific impulse, long lived ion thrusters, high power/high voltage power processors, accurate feed systems, and large propellant storage systems. Critical component work included high voltage insulators and isolators as well as ensuring that the thruster materials and components could operate in the substantial Jupiter radiation environment. A review of these developments along with future plans is discussed.

  11. Tectonics of Icy Moons: A Tale of Oceans and Orbital Dynamics

    NASA Astrophysics Data System (ADS)

    Kattenhorn, Simon

    2010-05-01

    Icy moons of the outer solar system commonly experience eccentric orbits that impart daily tidal stresses to the outer ice layer. Depending on the orbital dynamics and configuration of the moons and their host planets, these stresses may or may not be sufficiently large to deform the ice layer. Although the stresses are typically very small, many icy moons exhibit pervasively tectonized surfaces, replete with fractures, faults, and significant topography (e.g., Europa, Ganymede, Enceladus, Dione, Titan, Miranda, Ariel, Titania, Triton). Deformation may be driven by various means (e.g., orbital recession, polar wander, ice shell thickening), but tidal deformation is particularly important and is enhanced if an outer ice layer is decoupled from an underlying liquid ocean. The tidal response of the ocean creates tidal bulges in the ice layer that oscillate longitudinally and in amplitude during the orbital period. The resultant diurnal tidal stress field (perhaps 10s of kPa) rotates throughout the orbit. Any fractures growing in this time frame should thus be curved (e.g., Europa's cycloidal cracks, which have been cited as the smoking gun for a subsurface ocean). Long lineaments should accumulate strike-slip offsets in such a stress field, as occurs on Europa and perhaps Enceladus. The progressive development of ice ridges to either side of central cracks may result from this shearing process. A decoupled ice layer also permits faster than synchronous rotation of the ice layer, which may allow several MPa of stress to accrue, perhaps explaining long lineaments on Europa. It is unclear if Europa continues to be tectonically active, especially given apparent ice shell thickening that would have muted the tidal response through time. Nonetheless, subtle troughs across Europa's surface crosscut all other features and may indicate some degree of ongoing activity. In contrast, active tectonics on Enceladus is implied by ongoing geyser-like eruptions of water-ice from

  12. Analysis of Thrust Vectoring Capabilities for the Jupiter Icy Moons Orbiter

    NASA Technical Reports Server (NTRS)

    Quadrelli, Marco B .; Gromov, Konstantin; Murray, Emmanuell

    2005-01-01

    A strategy to mitigate the impact of the trajectory design of the Jupiter Icy Moons Orbiter (JIMO) on the attitude control design is described in this paper. This paper shows how the thrust vectoring control torques, i.e. the torques required to steer the vehicle, depend on various parameters (thrust magnitude, thrust pod articulation angles, and thrust moment arms). Rather than using the entire reaction control system (RCS) system to steer the spacecraft, we investigate the potential utilization of only thrust vectoring of the main ion engines for the required attitude control to follow the representative trajectory. This study has identified some segments of the representative trajectory where the required control torque may exceed the designed ion engine capability, and how the proposed mitigation strategy succeeds in reducing the attitude control torques to within the existing capability.

  13. Feasibility Study of Jupiter Icy Moons Orbiter Permanent Magnet Alternator Start Sequence

    NASA Technical Reports Server (NTRS)

    Kenny, Barbara H.; Tokars, Roger P.

    2006-01-01

    The Jupiter Icy Moons Orbiter (JIMO) mission was a proposed, (recently cancelled) long duration science mission to study three moons of Jupiter: Callisto, Ganymede, and Europa. One design of the JIMO spacecraft used a nuclear heat source in conjunction with a Brayton rotating machine to generate electrical power for the electric thrusters and the spacecraft bus. The basic operation of the closed cycle Brayton system was as follows. The working fluid, a heliumxenon gas mixture, first entered a compressor, then went through a recuperator and hot-side heat exchanger, then expanded across a turbine that drove an alternator, then entered the cold-side of the recuperator and heat exchanger and finally returned to the compressor. The spacecraft was to be launched with the Brayton system off-line and the nuclear reactor shut down. Once the system was started, the helium-xenon gas would be circulated into the heat exchangers as the nuclear reactors were activated. Initially, the alternator unit would operate as a motor so as to drive the turbine and compressor to get the cycle started. This report investigated the feasibility of the start up sequence of a permanent magnet (PM) machine, similar in operation to the alternator unit, without any position or speed feedback sensors ("sensorless") and with a variable load torque. It is found that the permanent magnet machine can start with sensorless control and a load torque of up to 30 percent of the rated value.

  14. An Overview of the Jupiter Icy Moons Orbiter (JIMO) Mission, Environments, and Materials Challenges

    NASA Technical Reports Server (NTRS)

    Edwards, Dave

    2012-01-01

    Congress authorized NASA's Prometheus Project in February 2003, with the first Prometheus mission slated to explore the icy moons of Jupiter with the following main objectives: (1) Develop a nuclear reactor that would provide unprecedented levels of power and show that it could be processed safely and operated reliably in space for long-duration. (2) Explore the three icy moons of Jupiter -- Callisto, Ganymede, and Europa -- and return science data that would meet the scientific goals as set forth in the Decadal Survey Report of the National Academy of Sciences.

  15. Environmental Change in Icy Moons

    NASA Astrophysics Data System (ADS)

    Pappalardo, R. T.; Vance, S.

    2014-12-01

    There is strong evidence that subsurface oceans could exist within several of the outer solar system's ice-rich moons, at Jupiter (Europa, Ganymede, and Callisto), Saturn (Enceladus and Titan), and Neptune (Triton). If liquid water is indeed available in these subsurface environments, then the availability of chemical energy becomes the greatest limitation on whether icy worlds could harbor life. Of these moons, the largest (Ganymede, Callisto, and Titan) are expected to harbor oceans deep within, and high-pressure H2O ice phases are expected farther beneath those deep oceans. In contrast, the oceans of smaller icy worlds—Europa, Enceladus, and Triton—are plausibly in direct contact with rock below. Given that serpentinization or other water-rock geochemical activity could supply reductants directly to their oceans, these icy worlds have the greatest chance to support present-day microbial life. Each of these three icy worlds displays spectacular resurfaced terrains that are very young (crater retention ages ~10s Myr and younger), with their internal activity linked to extremes in tidal heating today and/or in the geologically recent past. However, the degree of their tidal heating may have changed greatly over time. Europa is believed to experience cyclical tidal heating and activity; Enceladus may have experienced cyclical activity or a geologically recent pulse of activity; Triton may have experienced extreme tidal heating upon its capture and orbital circularization. Such dynamic pasts would pose challenges for any life within. We consider the possible effects of severe swings in the activity level of icy worlds, specifically the implications for delivery of chemical energy to their subsurface oceans.

  16. Main Power Distribution Unit for the Jupiter Icy Moons Orbiter (JIMO)

    NASA Technical Reports Server (NTRS)

    Papa, Melissa R.

    2004-01-01

    Around the year 2011, the Jupiter Icy Moons Orbiter (JIMO) will be launched and on its way to orbit three of Jupiter s planet-sized moons. The mission goals for the JIMO project revolve heavily around gathering scientific data concerning ingredients we, as humans, consider essential: water, energy and necessary chemical elements. The JIM0 is an ambitious mission which will implore propulsion from an ION thruster powered by a nuclear fission reactor. Glenn Research Center is responsible for the development of the dynamic power conversion, power management and distribution, heat rejection and ION thrusters. The first test phase for the JIM0 program concerns the High Power AC Power Management and Distribution (PMAD) Test Bed. The goal of this testing is to support electrical performance verification of the power systems. The test bed will incorporate a 2kW Brayton Rotating Unit (BRU) to simulate the nuclear reactor as well as two ION thrusters. The first module of the PMAD Test Bed to be designed is the Main Power Distribution Unit (MPDU) which relays the power input to the various propulsion systems and scientific instruments. The MPDU involves circuitry design as well as mechanical design to determine the placement of the components. The MPDU consists of fourteen relays of four different variations used to convert the input power into the appropriate power output. The three phase system uses 400 Vo1ts(sub L-L) rms at 1000 Hertz. The power is relayed through the circuit and distributed to the scientific instruments, the ION thrusters and other controlled systems. The mechanical design requires the components to be positioned for easy electrical wiring as well as allowing adequate room for the main buss bars, individual circuit boards connected to each component and power supplies. To accomplish creating a suitable design, AutoCAD was used as a drafting tool. By showing a visual layout of the components, it is easy to see where there is extra room or where the

  17. Feasibility Study of a Nuclear-Stirling Power Plant for the Jupiter Icy Moons Orbiter

    SciTech Connect

    Schmitz, Paul C.; Schreiber, Jeffrey G.; Penswick, L. Barry

    2005-02-06

    NASA is undertaking the design of a new spacecraft to explore the planet Jupiter and its three moons Calisto, Ganymede and Europa. This proposed mission, known as Jupiter Icy Moons Orbiter (JIMO) would use a nuclear reactor and an associated electrical generation system (Reactor Power Plant - RPP) to provide power to the spacecraft. The JIMO spacecraft is envisioned to use this power for science and communications as well as Electric Propulsion (EP). Among other potential power-generating concepts, previous studies have considered Thermoelectric and Brayton power conversion systems, coupled to a liquid metal reactor for the JIMO mission. This paper will explore trades in system mass and radiator area for a nuclear reactor power conversion system, however this study will focus on Stirling power conversion. Stirling convertors have a long heritage operating in both power generation and the cooler industry, and are currently in use in a wide variety of applications. The Stirling convertor modeled in this study is based upon the Component Test Power Convertor design that was designed and operated successfully under the Civil Space Technology Initiative for use with the SP-100 nuclear reactor in the 1980's and early 1990's. The baseline RPP considered in this study consists of four dual-opposed Stirling convertors connected to the reactor by a liquid lithium loop. The study design is such that two of the four convertors would operate at any time to generate the 100 kWe while the others are held in reserve. For this study the Stirling convertors hot-side temperature is 1050 K, would operate at a temperature ratio of 2.4 for a minimum mass system and would have a system efficiency of 29%. The Stirling convertor would generate high voltage (400 volt), 100 Hz single phase AC that is supplied to the Power Management and Distribution system. The waste heat is removed from the Stirling convertors by a flowing liquid sodium-potassium eutectic and then rejected by a shared

  18. Feasibility Study of a Nuclear-Stirling Plant for the Jupiter Icy Moons Orbiter

    NASA Technical Reports Server (NTRS)

    Schmitz, Paul C.; Schreiber, Jeffrey G.; Penswick, L. Barry

    2005-01-01

    NASA is undertaking the design of a new spacecraft to explore the planet Jupiter and its three moons Calisto, Ganymede and Europa. This proposed mission, known as Jupiter Icy Moons Orbiter (JIMO) would use a nuclear reactor and an associated electrical generation system (Reactor Power Plant-RPP) to provide power to the spacecraft. The JIMO spacecraft is envisioned to use this power for science and communications as well as Electric Propulsion (EP). Among other potential power-generating concepts, previous studies have considered Thermoelectric and Brayton Power conversion systems, coupled to a liquid metal reactor for the JIMO mission. This paper will explore trades in system mass and radiator area for a nuclear reactor power conversion system, however this study will focus on Stirling power conversion. The Stirling convertor modeled in this study is based upon the Component Test Power Convertor design that was designed and operated successfully under the Civil Space Technology Initiative for use with the SP-100 nuclear reactor i the 1980's and early 1990's. The study design is such that two of the four convertors would operate at any time to generate the 100 kWe while the others are held in reserve. For this study the Stirling convertors hot-side temperature is 1050 K, would operate at a temperature ratio of 2.4 for a minimum mass system and would have a system efficiency of 29%. The Stirling convertor would generate high voltage (400 volt), 100 Hz single phase AC that is supplied to the Power Management and Distribution system. The waste hear is removed from the Stirling convertors by a flowing liquid sodium-potassium eutectic and then rejected by a shared radiator. The radiator consists of two coplanar wings, which would be deployed after the reactor is in space. System trades were performed to vary cycle state point temperatures and convertor design as well as power output. Other redundancy combinations were considered to understand the affects of convertor

  19. Feasibility Study of a Nuclear-Stirling Power Plant for the Jupiter Icy Moons Orbiter

    NASA Astrophysics Data System (ADS)

    Schmitz, Paul C.; Schreiber, Jeffrey G.; Penswick, L. Barry

    2005-02-01

    NASA is undertaking the design of a new spacecraft to explore the planet Jupiter and its three moons Calisto, Ganymede and Europa. This proposed mission, known as Jupiter Icy Moons Orbiter (JIMO) would use a nuclear reactor and an associated electrical generation system (Reactor Power Plant - RPP) to provide power to the spacecraft. The JIMO spacecraft is envisioned to use this power for science and communications as well as Electric Propulsion (EP). Among other potential power-generating concepts, previous studies have considered Thermoelectric and Brayton power conversion systems, coupled to a liquid metal reactor for the JIMO mission. This paper will explore trades in system mass and radiator area for a nuclear reactor power conversion system, however this study will focus on Stirling power conversion. Stirling convertors have a long heritage operating in both power generation and the cooler industry, and are currently in use in a wide variety of applications. The Stirling convertor modeled in this study is based upon the Component Test Power Convertor design that was designed and operated successfully under the Civil Space Technology Initiative for use with the SP-100 nuclear reactor in the 1980's and early 1990's. The baseline RPP considered in this study consists of four dual-opposed Stirling convertors connected to the reactor by a liquid lithium loop. The study design is such that two of the four convertors would operate at any time to generate the 100 kWe while the others are held in reserve. For this study the Stirling convertors hot-side temperature is 1050 K, would operate at a temperature ratio of 2.4 for a minimum mass system and would have a system efficiency of 29%. The Stirling convertor would generate high voltage (400 volt), 100 Hz single phase AC that is supplied to the Power Management and Distribution system. The waste heat is removed from the Stirling convertors by a flowing liquid sodium-potassium eutectic and then rejected by a shared

  20. Traveling Wave Tube (TVT) RF Power Combining Demonstration for use in the Jupiter Icy Moons Orbiter (JIMO)

    NASA Technical Reports Server (NTRS)

    Downey, Joseph A.

    2004-01-01

    The Jupiter Icy Moons Orbiter (JIMO) is set to launch between the years 2012 and 2015. It will possibly utilize a nuclear reactor power source and ion engines as it travels to the moons of Jupiter. The nuclear reactor will produce hundreds of kilowatts of power for propulsion, communication and various scientific instruments. Hence, the RF amplification devices aboard will be able to operate at a higher power level and data rate. The initial plan for the communications system is for an output of 1000 watts of RF power, a data rate of at least 10 megabits a second, and a frequency of 32 GHz. A higher data rate would be ideal to fully utilize the instruments aboard JIMO. At NASA Glenn, one of our roles in the JIMO project is to demonstrate RF power combining using multiple traveling wave tubes (TWT). In order for the power of separate TWT s to be combined, the RF output waves from each must be in-phase and have the same amplitude. Since different tubes act differently, we had to characterize each tube using a Network Analyzer. We took frequency sweeps and power sweeps to characterize each tube to ensure that they will behave similarly under the same conditions. The 200 watt Dornier tubes had been optimized to run at a lower power level (120 watts) for their extensive use in the ACTS program, so we also had to experiment with adjusting the voltage settings on several internal components (helix, anode, collector) of the tubes to reach the full 200 watt potential. from the ACTS program. Phase shifters and power attenuators were placed in the waveguide circuit at the inputs to the tubes so that adjustments could be made individually to match them exactly. A magic tee was used to route and combine the amplified electromagnetic RF waves on the tube output side. The demonstration of 200 watts of combined power was successful with efficiencies greater than 90% over a 500 MHz bandwidth. The next step will be to demonstrate the use of three amplifiers using two magic tees by

  1. The Icy Moons of Jupiter

    NASA Astrophysics Data System (ADS)

    Greenberg, Richard

    The Galilean satellites formed in a nebula of dust and gas that surrounded Jupiter toward the end of the formation of the giant planet itself. Their diverse initial compositions were determined by conditions in the circum-jovian nebula, just as the planets' initial properties were governed by their formation within the circum-solar nebula. The Galilean satellites subsequently evolved under the complex interplay of orbital and geophysical processes, which included the effects of orbital resonances, tides, internal differentiation, and heat. The history and character of the satellites can be inferred from consideration of the formation of planets and the satellites, from studies of their plausible orbital evolution, from measurements of geophysical properties, especially gravitational and magnetic fields, from observations of the compositions and geological structure of their surfaces, and from geophysical modeling of the processes that can relate these lines of evidence. The three satellites with large water-ice components, Europa, Ganymede, and Callisto are very different from one another as a result of the ways that these processes have played out in each case. Europa has a deep liquid-water ocean with a thin layer of surface ice, Ganymede and Callisto likely have relatively thin liquid water layers deep below their surfaces, and Callisto remains only partially differentiated, with rock and ice mixed through much of its interior. A tiny inner satellite, Amalthea, also appears to be largely composed of ice. Each of these moons is fascinating in its own right, and the ensemble provides a powerful set of constraints on the processes that led to their formation and evolution.

  2. The long-period librations of large synchronous icy moons

    NASA Astrophysics Data System (ADS)

    Yseboodt, Marie; Van Hoolst, Tim

    2014-11-01

    A moon in synchronous rotation has longitudinal librations because of its non-spherical mass distribution and its elliptical orbit around the planet. We study the long-period librations of the Galilean satellites and Titan and include deformation effects and the existence of a subsurface ocean. We take into account the fact that the orbit is not keplerian and has other periodicities than the main period of orbital motion around Jupiter or Saturn due to perturbations by the Sun, other planets and moons. An orbital theory is used to compute the orbital perturbations due to these other bodies. For Titan we also take into account the large atmospheric torque at the semi-annual period of Saturn around the Sun.We numerically evaluate the amplitude and phase of the long-period librations for many interior structure models of the icy moons constrained by the mass, radius and gravity field.

  3. Surface radiation environment of Saturn's icy moon Mimas

    NASA Astrophysics Data System (ADS)

    Nordheim, T.; Hand, K. P.; Paranicas, C.; Kollmann, P.; Jones, G. H.; Coates, A. J.; Krupp, N.

    2012-09-01

    The majority of the large icy satellites that orbit Jupiter and Saturn are embedded within the magnetospheres of their respective parent bodies. The inner regions of these magnetospheric environments are characterized by populations of trapped charged particles, from thermal plasma to high energy energetic ions and electrons. Moons orbiting within these magnetospheres are therefore often subject to continuous bombardment by multiple particle species over a wide range of energies. It is known that such bombardment may induce chemical alterations within icy surfaces through the process of radiolysis, an effect which has the potential to significantly change surface and near-surface composition over typical geological timescales. In order to make quantifiable predictions on the surface composition of these moons, it is therefore critical to have a detailed measure of deposited dose into the surface from the relevant magnetospheric particle species. Saturn's innermost large moon Mimas orbits within one of the harshest radiation environments of the Saturnian magnetosphere and remote sensing observations of the moon have revealed a surface that displays strong signs of magnetospheric weathering. It is therefore of great interest to further quantify the interaction of magnetospheric particles with the Mimantean surface, particularly with regards to determining which bombarding species dominate at different moon surface locations and surface depths and to compare this with remote sensing observations. We will present dose-depth profiles for the nearsurface which have been computed using a Monte Carlo particle transport code and representative energetic electron and proton spectra derived from measurements made by the MIMI-LEMMS particle instrument on the Cassini spacecraft.

  4. ARTEMIS Orbits Magnetic Moon

    NASA Video Gallery

    NASA's THEMIS spacecraft have completed their mission and are still working perfectly, so NASA is re-directing the outermost two spacecraft to special orbits around the Moon. Now called ARTEMIS, th...

  5. Geologic Evolution of Saturn's Icy Moon Tethys

    NASA Astrophysics Data System (ADS)

    Wagner, Roland; Stephan, K.; Schmedemann, N.; Roatsch, T.; Kersten, E.; Neukum, G.; Porco, C. C.

    2013-10-01

    Tethys, 1072 km in diameter, is a mid-sized icy moon of Saturn imaged for the first time in two Voyager flybys [1][2][3]. Since July 2004, its surface has been imaged by the Cassini ISS cameras at resolutions between 200 and 500 m/pxl. We present results from our ongoing work to define and map geologic units in camera images obtained preferentially during Cassini’s Equinox and Solstice mission phases. In the majority of Tethys’ surface area a densely cratered plains unit [1][2][3][this work] is abundant. The prominent graben system of Ithaca Chasma is mapped as fractured cratered plains. Impact crater and basin materials can be subdivided into three degradational classes. Odysseus is a fresh large impact basin younger than Ithaca Chasma according to crater counts [4]. Heavily degraded craters and basins occur in the densely cratered plains unit. A smooth, less densely cratered plains unit in the trailing hemisphere was previously identified by [2] but mapping of its boundaries is difficult due to varying viewing geometries of ISS images. To the south of Odysseus, we identified a cratered plains unit not seen in Voyager data, characterized by remnants of highly degraded large craters superimposed by younger fresher craters with a lower crater density compared to the densely cratered plains unit. Its distinct linear northern contact with the densely cratered plains suggests a tectonic origin. Sets of minor fractures can be distinguished in the densely cratered plains, and locally, features of mass wasting can be observed. References: [1] Smith B. A. et al. (1981), Science 212, 163-191. [2] Smith B. A. et al. (1982), Science 215, 504-537. [3] Moore J. M. and Ahern J. L. (1983), JGR 88 (suppl.), A577-A584. [4] Giese B. et al. (2007), GRL 34, doi:10.1029/2007GL031467.

  6. Ganymede Europa Neutral Imaging Experiment at the Jupiter's icy moons

    NASA Astrophysics Data System (ADS)

    Milillo, A.; Orsini, S.; Plainaki, C.; DeAngelis, E.; Argan, A.; Fierro, D.; Vertolli, N.; Danduras, I.; Selci, S.; Leoni, R.; Sheer, J.

    2012-04-01

    GENIE (Ganymede Europa Neutral Imaging Experiment) (energy range 10 eV - 10 keV) is a high-angular-resolution detector, based on the ToF technique. Its objective is to map the origin sites of the most energetic neutral particles of the icy moons' exospheres, in order to investigate the interaction between the surface and the environment. The investigation of plasma interaction with the Jupiter's moons and the processes responsible for surface space weathering is one of the coolest topics of the proposed Cosmic Vision mission JUICE since it directly relates to energy exchange within the Jupiter's system, to the moon evolution and finally to the habitability in the harsh radiative environment. Icy surfaces of the Jupiter's moons are continuously irradiated by intense ion fluxes of H+, O+ and S+ in the energy range from keV to MeV. These ions are expected to impact the moon icy surface producing relevant and observable effects such as particles release and chemical and structural modifications of the surface. In particular, the plasma impacting onto the surface causes, via ion-sputtering, radiolysis and backscattering processes, release of neutrals that constitute the exospheres. The energy spectrum of this particle population peaks in the eV range with a non-negligible tail up to hundred eVs. The knowledge of the effectiveness of these processes in this environment is important in order to understand the evolution of the moons and their interactions within the Jupiter's system. The detection of neutral atoms above few 10 eVs (LENA) is a way to univocally relate the exosphere to surface features and to monitor instantaneously the effect of plasma precipitation onto the surface. Thus, GENIE is fully complementary to INM spectrometer, devoted to infer exospheric composition and density. Coupled measurements of LENA and gas composition will improve our knowledge in surface release mechanisms. The observation of LENA at different latitudes and longitudes, resulting in a 2

  7. Radar Sounding for Planetary Subsurface Exploration: Translating the Mars Experience to Jupiter's Icy Moons

    NASA Astrophysics Data System (ADS)

    Plaut, J.

    2015-12-01

    Exploration of the subsurface of Mars using radar sounding began with MARSIS (Mars Advanced Radar for Subsurface and Ionospheric Sounding) on Mars Express in 2005 and continued with SHARAD (Shallow Radar) on Mars Reconnaissance Orbiter in 2006. These instruments have been operating continuously since, providing a rich legacy of science return and observational experience in the highly variable environments and target sets at Mars. New missions to the icy moons of Jupiter, ESA's JUICE (Jupiter Icy Moon Explorer) and NASA's Europa Mission, will both carry radar sounders to probe the subsurface of several of the icy moons (Ganymede, Europa and Callisto by JUICE; Europa by the Europa Mission). The success of the Mars sounders demonstrated the scientific value of the technique and provided confidence that sounding of the icy moons is a promising endeavor. Icy targets at Mars have proven especially amenable to penetration by radar sounding. The polar layered deposits of Mars have been probed to their base (2-4 km deep) by MARSIS, operating at frequencies of 1.3-5.5 MHz. SHARAD, operating with a wider bandwidth at 15-25 MHz, provides higher vertical resolution that allows detection and imaging of fine details of interior layering in the ice deposits. The sounder planned for the Europa mission, REASON (Radar for Europa Assessment and Sounding, Ocean to Near-Surface), will utilize simultaneous dual frequency signals to obtain complementary deep sounding and high-vertical-resolution shallow observations. Co-located observations by MARSIS and SHARAD also demonstrate that high surface roughness (relative to the radar wavelength) affects the strength of the penetrating signals, and thus the capability to detect deep or low-contrast subsurface interfaces. The icy moon sounders' wavelengths were selected, in part, to mitigate against this degradation of signals by the anticipated rough surfaces of Jupiter's moons. This paper will discusss these and other examples of lessons

  8. Habitability potential of icy moons: a comparative study

    NASA Astrophysics Data System (ADS)

    Solomonidou, Anezina; Coustenis, Athena; Encrenaz, Thérèse; Sohl, Frank; Hussmann, Hauke; Bampasidis, Georgios; Wagner, Frank; Raulin, François; Schulze-Makuch, Dirk; Lopes, Rosaly

    2014-05-01

    Looking for habitable conditions in the outer solar system our research focuses on the natural satellites rather than the planets themselves. Indeed, the habitable zone as traditionally defined may be larger than originally con-ceived. The strong gravitational pull caused by the giant planets may produce enough energy to sufficiently heat the interiors of orbiting icy moons. The outer solar system satellites then provide a conceptual basis within which new theories for understanding habitability can be constructed. Measurements from the ground but also by the Voyager, Galileo and the Cassini spacecrafts revealed the potential of these satellites in this context, and our understanding of habitability in the solar system and beyond can be greatly enhanced by investigating several of these bodies together [1]. Their environments seem to satisfy many of the "classical" criteria for habitability (liquid water, energy sources to sustain metabolism and chemical compounds that can be used as nutrients over a period of time long enough to allow the development of life). Indeed, several of the moons show promising conditions for habitability and the de-velopment and/or maintenance of life. Europa, Callisto and Ganymede may be hiding, under their icy crust, putative undersurface liquid water oceans [3] which, in the case of Europa [2], may be in direct contact with a silicate mantle floor and kept warm by tidally generated heat [4]. Titan and Enceladus, Saturn's satellites, were found by the Cassini-Huygens mission to possess active organic chemistries with seasonal variations, unique geological features and possibly internal liquid water oceans. Titan's rigid crust and the probable existence of a subsurface ocean create an analogy with terrestrial-type plate tectonics, at least surficial [5], while Enceladus' plumes find an analogue in gey-sers. As revealed by Cassini the liquid hydrocarbon lakes [6] distributed mainly at polar latitudes on Titan are ideal isolated

  9. JUICE: a European mission to Jupiter and its icy moons

    NASA Astrophysics Data System (ADS)

    Titov, D.; Erd, C.; Duvet, L.; Wielders, A.; Torralba-Elipe, I.; Altobelli, N.

    2013-09-01

    JUICE (JUpiter ICy moons Explorer) is the first L-class mission selected for the ESA's Cosmic Vision programme 2015-2025 which has just entered the definition phase. JUICE will perform detailed investigations of Jupiter and its system in all their inter-relations and complexity with particular emphasis on Ganymede as a planetary body and potential habitat. Investigations of Europa and Callisto will complete a comparative picture of the Galilean moons. By performing detailed investigations of Jupiter's system, JUICE will address in depth two key questions of the ESA's Cosmic Vision programme: (1) What are the conditions for planet formation and the emergence of life? and (2) How does the Solar System work? The overarching theme for JUICE has been formulated as: The emergence of habitable worlds around gas giants. At Ganymede the mission will characterize in detail the ocean layers; provide topographical, geological and compositional mapping of the surface; study the physical properties of the icy crusts; characterize the internal mass distribution, investigate the exosphere; study Ganymede's intrinsic magnetic field and its interactions with the Jovian magnetosphere. For Europa, the focus will be on the non-ice chemistry, understanding the formation of surface features and subsurface sounding of the icy crust over recently active regions. Callisto will be explored as a witness of the early solar system. JUICE will perform a comprehensive multidisciplinary investigation of the Jupiter system as an archetype for gas giants including exoplanets. The circulation, meteorology, chemistry and structure of the Jovian atmosphere will be studied from the cloud tops to the thermosphere. The focus in Jupiter's magnetosphere will include an investigation of the three dimensional properties of the magnetodisc and in-depth study of the coupling processes within the magnetosphere, ionosphere and thermosphere. Aurora and radio emissions and their response to the solar wind will be

  10. Jupiter Icy Moons Explorer: mission status after the Definition Phase

    NASA Astrophysics Data System (ADS)

    Titov, Dmitri; Barabash, Stas; Bruzzone, Lorenzo; Dougherty, Michele; Erd, Christian; Fletcher, Leigh; Gare, Philippe; Gladstone, Randall; Grasset, Olivier; Gurvits, Leonid; Hartogh, Paul; Hussmann, Hauke; Iess, Luciano; Jaumann, Ralf; Langevin, Yves; Palumbo, Pasquale; Piccioni, Giuseppe; Sarri, Giuseppe; Wahlund, Jan-Erik; Witasse, Olivier

    2015-04-01

    JUpiter ICy moons Explorer (JUICE), the ESA first large-class mission within the Cosmic Vision Program 2015-2025, was adopted in November 2014. The mission will perform detailed investigations of Jupiter and its system with particular emphasis on Ganymede as a planetary body and potential habitat. The overarching theme for JUICE is: The emergence of habitable worlds around gas giants. At Ganymede, the mission will characterize in detail the ocean layers; provide topographical, geological and compositional mapping of the surface; study the physical properties of the icy crusts; characterize the internal mass distribution, investigate the exosphere; study Ganymede's intrinsic magnetic field and its interactions with the Jovian magnetosphere. For Europa, the focus will be on the non-ice chemistry, understanding the formation of surface features and subsurface sounding of the icy crust over recently active regions. Callisto will be explored as a witness of the early solar system. JUICE will perform a multidisciplinary investigation of the Jupiter system as an archetype for gas giants. The circulation, meteorology, chemistry and structure of the Jovian atmosphere will be studied from the cloud tops to the thermosphere. The focus in Jupiter's magnetosphere will include an investigation of the three dimensional properties of the magnetodisc and in-depth study of the coupling processes within the magnetosphere, ionosphere and thermosphere. Aurora and radio emissions will be elucidated. JUICE will study the moons' interactions with the magnetosphere, gravitational coupling and long-term tidal evolution of the Galilean satellites. JUICE highly capable scientific payload includes 10 state-of-the-art instruments onboard the spacecraft plus one experiment that uses the spacecraft telecommunication system with ground-based radio telescopes. The remote sensing package includes a high-resolution multi-band visible imager (JANUS) and spectro-imaging capabilities from the

  11. JUICE: A European Mission to Jupiter and its Icy Moons

    NASA Astrophysics Data System (ADS)

    Witasse, O.; Altobelli, N.; Barabash, S.; Bruzzone, L.; Dougherty, M.; Erd, C.; Fletcher, L.; Gladstone, R.; Grasset, O.; Gurvits, L.; Hartogh, P.; Hussmann, H.; Iess, I.; Langevin, Y.; Palumbo, P.; Piccioni, G.; Sarri, G.; Titov, D.; Wahlund, J.-E.

    2015-10-01

    JUICE -JUpiter ICy moons Explorer -is the first large mission in the ESA Cosmic Vision 2015-2025 programme[1]. The mission was selected in May 2012 and adopted in November 2014. The implementation phase starts in July 2015, following the selection of the prime industrial contractor. Planned for launch in June 2022 and arrival at Jupiter in October 2029, it will spend at least three years making detailed observations of Jupiter and three of its largest moons, Ganymede, Callisto and Europa.

  12. Neutral atmosphere near the icy surface of Jupiter's moon Ganymede

    NASA Astrophysics Data System (ADS)

    Shematovich, V. I.

    2016-07-01

    The paper discusses the formation and dynamics of the rarefied gas envelope near the icy surface of Jupiter's moon Ganymede. Being the most massive icy moon, Ganymede can form a rarefied exosphere with a relatively dense near-surface layer. The main parent component of the gas shell is water vapor, which enters the atmosphere due to thermal degassing, nonthermal radiolysis, and other active processes and phenomena on the moon's icy surface. A numerical kinetic simulation is performed to investigate, at the molecular level, the formation, chemical evolution, and dynamics of the mainly H2O- and O2-dominant rarefied gas envelopes. The ionization processes in these rarefied gas envelopes are due to exposure to ultraviolet radiation from the Sun and the magnetospheric plasma. The chemical diversity of the icy moon's gas envelope is attributed to the primary action of ultraviolet solar photons and plasma electrons on the rarefied gas in the H2O- or O2-dominant atmosphere. The model is used to calculate the formation and development of the chemical diversity in the relatively dense near-surface envelope of Ganymede, where an important contribution comes from collisions between parent molecules and the products of their photolysis and radiolysis.

  13. The Radar for Icy Moon Exploration (RIME) on the JUICE Mission

    NASA Astrophysics Data System (ADS)

    Bruzzone, L.; Plaut, J.; Alberti, G.; Blankenship, D. D.; Bovolo, F.; Campbell, B. A.; Castelletti, D.; Gim, Y.; Ilisei, A. M.; Kofman, W. W.; Komatsu, G.; McKinnon, W. B.; Mitri, G.; Moussessian, A.; Notarnicola, C.; Orosei, R.; Patterson, G. W.; Pettinelli, E.; Plettemeier, D.

    2015-12-01

    The Radar for Icy Moon Exploration (RIME) is one of the main instruments included in the JUpiter ICy moons Explorer (JUICE) ESA mission. It is a radar sounder designed for studying the subsurface geology and geophysics of Galilean icy moons (i.e., Ganymede, Europa and Callisto) and for detecting possible subsurface water. RIME is designed for penetration of the icy moons up to a depth of 9 km. Two main operation scenarios are foreseen for RIME: i) flyby observations of Europa, Ganymede and Callisto (from a distance of 1000 km to the closest approach of about 400 km); and ii) circular orbital observations around Ganymede at 500 km of altitude. According to these scenarios, RIME is designed to explore the icy shell of the Galilean icy satellites by characterizing the wide range of compositional, thermal, and structural variation found in the subsurface of these moons. RIME observations will profile the ice shells of the Galilean icy satellites with specific focus on Ganymede given the circular orbital phase. The acquired measures will provide geological context on hemispheric (thousands of km), regional (hundreds of km with multiple overlaps), and targeted (tens of km) scales appropriate for a variety of hypothesis tests. RIME will operate in a single frequency band, centred at 9 MHz. The frequency was selected as the result of extensive study of penetration capabilities, surface roughness of the moons, Jovian radio noise, antenna accommodation, and system design. The 9 MHz frequency provides penetration capabilities and mitigation of surface scattering (which can cause signal loss and clutter issues), at the expense of mapping coverage, as it is likely to obtain high SNR observations only on the anti-Jovian side of the target moons. The RIME antenna is a 16 m dipole. The chirp pulse bandwidth is up to 3 MHz, which provides vertical resolution of about 50 m in ice after side lobe weighting. RIME will also operate with 1 MHz bandwidth to reduce data volume when

  14. Exobiology and Planetary Protection of icy moons

    NASA Astrophysics Data System (ADS)

    Raulin, François; Hand, Kevin P.; McKay, Christopher P.; Viso, Michel

    2010-06-01

    The outer solar system is an important area of investigation for exobiology, the study of life in the universe. Several moons of the outer planets involve processes and structures comparable to those thought to have played an important role in the emergence of life on Earth, such as the formation and exchange of organic materials between different reservoirs. The study of these prebiotic processes on, and in, outer solar system moons is a key goal for exobiology, together with the question of habitability and the search for evidence of past or even present life. This chapter reviews the aspects of prebiotic chemistry and potential presence of life on Europa, Enceladus and Titan, based on the most recent data obtained from space missions as well as theoretical and experimental laboratory models. The habitability of these extraterrestrial environments, which are likely to include large reservoirs of liquid water in their internal structure, is discussed as well as the particular case of Titan’s hydrocarbon lakes. The question of planetary protection, especially in the case of Europa, is also presented.

  15. Crustal failure on icy Moons from a strong tidal encounter

    NASA Astrophysics Data System (ADS)

    Quillen, Alice C.; Giannella, David; Shaw, John G.; Ebinger, Cynthia

    2016-09-01

    Close tidal encounters among large planetesimals and Moons should have been more common than grazing or normal impacts. Using a mass spring model within an N-body simulation, we simulate the deformation of the surface of an elastic spherical body caused by a close parabolic tidal encounter with a body that has similar mass as that of the primary body. Such an encounter can induce sufficient stress on the surface to cause brittle failure of an icy crust and simulated fractures can extend a large fraction of the radius of body. Strong tidal encounters may be responsible for the formation of long graben complexes and chasmata in ancient terrain of icy Moons such as Dione, Tethys, Ariel and Charon.

  16. 2017 Eclipse and the Moon's Orbit

    NASA Video Gallery

    Solar eclipses can only occur at New Moon, when the Moon is between the Earth and the Sun. But not every New Moon produces an eclipse. The Moon's orbit is slightly tilted, and as seen in this anima...

  17. Lunar Orbiter I - Moon & Earth

    NASA Technical Reports Server (NTRS)

    1966-01-01

    First view of the earth and moon from space. Published in: Spaceflight Revolution: Langley Research Center From Sputnik to Apollo, by James R. Hansen. NASA History Series. NASA SP ; 4308. p ii. Caption: 'The picture of the century was this first view of the earth from space. Lunar Orbiter I took the photo on 23 August 1966 on its 16th orbit just before it passed behind the moon. The photo also provided a spectacular dimensional view of the lunar surface.'

  18. Lunar Orbiter: Moon and Earth

    NASA Technical Reports Server (NTRS)

    1966-01-01

    The worlds first view of the Earth taken by a spacecraft from the vicinity of the Moon. The photo was transmitted to Earth by the United States Lunar Orbiter I and recieved at the NASA tracking station at Robledo de Chavela near Madrid, Spain. This crescent of the Earth was photographed August 23 at 16:35 GMT when the spacecraft was on its 16th orbit and just about to pass behind the Moon. This is the view the astronauts will have when they come around the backside of the Moon and face the Earth. The Earth is shown on the left of the photo with the U.S. east coast in the upper left, southern Europe toward the dark or night side of the Earth, and Antartica at the bottom of the Earth crescent. The surface of the Moon is shown on the right side of the photograph.

  19. Regional geology and stratigraphy of Saturn's icy moon Tethys

    NASA Astrophysics Data System (ADS)

    Wagner, Roland; Stephan, Katrin; Schmedemann, Nico; Roatsch, Thomas; Kersten, Elke; Neukum, Gerhard; Porco, Carolyn C.

    2013-04-01

    Tethys, with a diameter of 1060 km one of the 6 mid-sized icy moons of Saturn, was imaged for the first time in the early 1980ies by the cameras aboard the two Voyager spacecraft at resolutions of 1 km/pxl and lower [1][2][3]. These images show that most of Tethys is densely cratered and displays two major landmarks: the ~ 400 km large impact structure Odysseus and the huge graben system of Ithaca Chasma [1][2]. Since July 2004, Cassini has been in orbit about Saturn and has made several close passes at Tethys, providing an almost complete global image coverage at regional scale (200 - 500 m/pxl). However, varying viewing geometries between images taken during different orbits still impede the identification and mapping of geologic units. In this work we present an update of Tethys' regional geology and stratigraphy, based on Cassini ISS images. Crater distribution measurements, by us and in comparison with measurements of other groups [4], are used to support stratigraphic findings. Most of Tethys' surface consists of a hilly, rugged, heavily cratered plains unit, as identified in Voyager images [1][2][3]. A smooth, less densely cratered plains unit in the trailing hemisphere was previously observed by [2] which is also identifiable in Cassini ISS, but its exact boundaries are difficult to map due to varying viewing geometries of ISS observations. Another sparsely cratered plains unit not seen in Voyager images can be located to the south of Odysseus. It features remnants of highly degraded large craters superimposed by younger fresher craters with a lower crater density compared to the heavily cratered plains. Its distinct linear northern contact with the heavily cratered plains suggests an origin related to tectonism. Again, varying viewing conditions hamper to map the exact boundaries of this unit. The prominent graben system of Ithaca Chasma represents fractured cratered plains. The high resolution of Cassini ISS images reveals that tectonism on Tethys is more

  20. High energy electron processing of icy regoliths on Saturn's moons

    NASA Astrophysics Data System (ADS)

    Schaible, Micah; Johnson, Robert E.

    2015-11-01

    A unique space weathering phenomenon has been identified on several icy Saturnian moons. Cassini revealed anomalous lens shaped regions in both optical and thermal wavelengths, colloquially known as the 'PacMan' feature, which are centered on the leading hemispheres and approximately symmetric about the equators. In particular, the Cassini InfraRed Spectrometer (CIRS) measurements of thermal emission in the mid-IR showed that surface temperature variations during a diurnal cycle were smaller inside the anomalous regions. The locations of the anomalies were shown to closely match the expected deposition profile of high energy (~ MeV) electrons moving counter rotational to the moons, suggesting an energetic source to drive their formation. However, the mechanisms by which thermal conductivity enhancement occur lack quantitative comparison with theoretical and experimental results.Electron interactions with the grains can excite molecules, which, if near enough to an intergrain contact, can cause atoms or molecules to migrate into the contact region, thus increasing the contact volume or 'sintering' the grains. Sintering improves the thermal contact between grains, leading to increased effective thermal conductivity of the regolith. Equations previously developed to describe material behavior in nuclear reactor were used to estimate the timescale for the energetic electrons to increase the contact volume sufficiently to describe the enhanced thermal conductivity of the anomalous regions. In order to properly constrain the sintering calculations, the unique electron energy distribution measured in the vicinity of each of the moons was used in the calculations, and molecular dynamics simulations of excited electrons in water ice were carried out to determine the length scale for an average electron excitation or ionization event. This length scale determines the distance from the primary reaction at which electrons can still be mobilized to move into the contact region

  1. Investigating Saturn's Icy Moons using HST/STIS

    NASA Astrophysics Data System (ADS)

    Hendrix, A. R.; Noll, K. S.; Spencer, J. R.

    2015-12-01

    The inner moons of Saturn - Mimas, Enceladus, Tethys, Dione and Rhea - exhibit remarkable large-scale albedo and color variations. These trends can be linked to a combination of the unique exogenic processes occurring the Saturn system, including E-ring grain bombardment and charged particle bombardment. One of the fascinating characteristics of the Saturn system is that the icy satellites, though their surface compositions are dominated by water ice, are spectrally red - they are absorbing in the ultraviolet-visible wavelength region (wavelengths <~550 nm) - a spectral feature not typical of pure water ice. In fact, the existing data show that in the UV, absorptions appear to be present superimposed on the overall red slope. Thus, though Cassini instruments have learned much about the surfaces of the icy moons, a basic question that remains is: What is their surface composition and what are the species or processes that cause these UV absorptions? Cassini's spectral coverage is lacking in precisely the near-UV wavelength regime in which the satellites appear to absorb most strongly. To resolve this issue and determine some understanding of the surface species present, we have obtained data using HST/STIS (Space Telescope Imaging Spectrograph). We have utilized the STIS G230L detector to obtain high SNR spectra in the 180-320 nm region along with short G430L exposures to obtain spectra in the 320-570 nm range, to completely fill in the Cassini gap in spectral coverage. Full-disk measurements have been made of the trailing and leading hemispheres of Mimas, Dione and Rhea; a spectrum of Enceladus was also obtained. We report on the results. In particular, we discuss implications for the presence of ammonia, ozone and organics.

  2. Radio Sounding Techniques for the Galilean Icy Moons and their Jovian Magnetospheric Environment

    NASA Technical Reports Server (NTRS)

    Green, James L.; Markus, Thursten; Fung, Shing F.; Benson, Robert F.; Reinich, Bodo W.; Song, Paul; Gogineni, S. Prasad; Cooper, John F.; Taylor, William W. L.; Garcia, Leonard

    2004-01-01

    Radio sounding of the Earth's topside ionosphere and magnetosphere is a proven technique from geospace missions such as the International Satellites for Ionospheric Studies (ISIS) and the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE). Application of this technique to Jupiter's icy moons and the surrounding Jovian magnetosphere will provide unique remote sensing observations of the plasma and magnetic field environments and the subsurface conductivities, of Europa, Ganymede, and Callisto. Spatial structures of ionospheric plasma above the surfaces of the moons vary in response to magnetic-field perturbations from (1) magnetospheric plasma flows, (2) ionospheric currents from ionization of sputtered surface material, and (3) induced electric currents in salty subsurface oceans and from the plasma flows and ionospheric currents themselves. Radio sounding from 3 kHz to 10 MHz can provide the global electron densities necessary for the extraction of the oceanic current signals and supplements in-situ plasma and magnetic field measurements. While radio sounding requires high transmitter power for subsurface sounding, little power is needed to probe the electron density and magnetic field intensity near the spacecraft. For subsurface sounding, reflections occur at changes in the dielectric index, e.g., at the interfaces between two different phases of water or between water and soil. Variations in sub-surface conductivity of the icy moons can be investigated by radio sounding in the frequency range from 10 MHz to 50 MHz, allowing the determination of the presence of density and solid-liquid phase boundaries associated with oceans and related structures in overlying ice crusts. The detection of subsurface oceans underneath the icy crusts of the Jovian moons is one of the primary objectives of the Jupiter Icy Moons Orbiter (JIMO) mission. Preliminary modeling results show that return signals are clearly distinguishable be&een an ice crust with a thickness of

  3. Habitability of the giant icy moons: current knowledge and future insights from the JUICE mission

    NASA Astrophysics Data System (ADS)

    Grasset, O.; Prieto-Ballesteros, O.; Titov, D.; Erd, C.; Bunce, E.; Coustenis, A.; Blanc, M.; Coates, A.; Fletcher, L.; van Hoolst, T.; Hussmann, H.; Jaumann, R.; Krupp, N.; Tortora, P.; Tosi, F.; Wielders, A.

    2012-09-01

    Large satellites of gas giants, at orbits beyond the snow-line, such as Jupiter or Saturn, can contain a large amount of water (almost 45% in mass). Hydrospheres are extremely thick, ~600 km for Ganymede and Callisto, and may possess liquid layers below the icy crust. Thus, the Galilean satellites provide a conceptual basis within which new theories for understanding habitability can be constructed. Measurements from the Voyager and Galileo spacecraft revealed the potential of these satellites in this context. The JUpiter Icy moons Explorer (JUICE) will greatly enhance our understanding of their potential habitability. It is known, even at Earth where life mostly depends on solar energy, that habitats exist deep in the oceans in eternal darkness feeding on chemical energy. Aqueous layers are suspected below the icy crusts of the moons, which possess similar physical characteristics than Earth's deep oceans. Since they are certainly very stable through time, and because complex chemistry and energy sources may be available, life may have originated within such subsurface habitats despite the hostile surface conditions. Liquid water reservoirs have been proposed on Ganymede, Europa and Callisto from geophysical models, based on Galileo observations. These oceans that are covered by ice shells exist independently of the input of stellar energy, and are located well outside the conventional habitable zone of the Sun. Considering the pressure range encountered within the icy moons, four different scenarios can be defined. These result from varying thicknesses of the water ice layers and the liquid ocean with respect to the silicate floor (Figure 1). Case 2 in Figure 1 is highly probable for the largest moons (Ganymede and Callisto), while case 3 is more probable for Europa and smaller icy moons if they host liquid reservoirs such as has been discovered at Enceladus. Europa's ocean is unique because it may be in contact with the rock layer. This substrate may be

  4. The dust halo of Saturn's largest icy moon, Rhea.

    PubMed

    Jones, G H; Roussos, E; Krupp, N; Beckmann, U; Coates, A J; Crary, F; Dandouras, I; Dikarev, V; Dougherty, M K; Garnier, P; Hansen, C J; Hendrix, A R; Hospodarsky, G B; Johnson, R E; Kempf, S; Khurana, K K; Krimigis, S M; Krüger, H; Kurth, W S; Lagg, A; McAndrews, H J; Mitchell, D G; Paranicas, C; Postberg, F; Russell, C T; Saur, J; Seiss, M; Spahn, F; Srama, R; Strobel, D F; Tokar, R; Wahlund, J-E; Wilson, R J; Woch, J; Young, D

    2008-03-01

    Saturn's moon Rhea had been considered massive enough to retain a thin, externally generated atmosphere capable of locally affecting Saturn's magnetosphere. The Cassini spacecraft's in situ observations reveal that energetic electrons are depleted in the moon's vicinity. The absence of a substantial exosphere implies that Rhea's magnetospheric interaction region, rather than being exclusively induced by sputtered gas and its products, likely contains solid material that can absorb magnetospheric particles. Combined observations from several instruments suggest that this material is in the form of grains and boulders up to several decimetres in size and orbits Rhea as an equatorial debris disk. Within this disk may reside denser, discrete rings or arcs of material. PMID:18323452

  5. Iceless Icy Moons: Is the Nice Model In Trouble?

    NASA Astrophysics Data System (ADS)

    Dones, Henry C. Luke; Levison, H. F.

    2012-05-01

    Nimmo and Korycansky (2012; henceforth NK12) stated that if the outer Solar System underwent a Late Heavy Bombardment (LHB) in the Nice model, the mass striking the icy satellites at speeds up to tens of km/s would have vaporized so much ice that moons such as Mimas, Enceladus, and Miranda would have been devolatilized. NK12's possible explanations of this apparent discrepancy with observations include (1) the mass influx was a factor of 10 less than that in the Nice model; (2) the mass distribution of the impactors was top-heavy, so that luck might have saved some of the moons from suffering large, vapor-removing impacts; or (3) the inner moons formed after the LHB. NK12 calculated the mass influx onto the satellites from the lunar impact rate estimated by Gomes et al. (2005) and scaling factors calculated by Zahnle et al. (1998, 2003; also see Barr and Canup 2010). Production of vapor in hypervelocity impacts is calculated from Kraus et al. (2011). Our preliminary results show that there is about an order-of-magnitude uncertainty in the mass striking the satellites during the LHB, with NK12's estimate at the upper end of the range. We will discuss how the mass influx depends on the velocity and mass distributions of the impactors. The Nice model lives. We thank the NASA Lunar Science Institute (http://lunarscience.nasa.gov/) for support. Barr, A.C., Canup, R.M., Nature Geoscience 3, 164-167 (2010). Gomes, R., Levison, H.F., Tsiganis, K., Morbidelli, A., Nature 435, 466-469 (2005). Kraus, R.G., Senft, L.E., Stewart, S.T., Icarus 214, 724-738 (2011). Nimmo, F., Korycansky, D.G., Icarus, in press, http://www.sciencedirect.com/science/article/pii/S0019103512000310 (2012). Zahnle, K., Dones, L., Levison, H.F., Icarus 136, 202-222 (1998). Zahnle, K., Schenk, P., Levison, H.F., Dones, L., Icarus 163, 263-289 (2003).

  6. Polymerization of Building Blocks of Life on Europa and Other Icy Moons.

    PubMed

    Kimura, Jun; Kitadai, Norio

    2015-06-01

    The outer Solar System may provide a potential habitat for extraterrestrial life. Remote sensing data from the Galileo spacecraft suggest that the jovian icy moons--Europa, Ganymede, and possibly Callisto--may harbor liquid water oceans underneath their icy crusts. Although compositional information required for the discussion of habitability is limited because of significantly restricted observation data, organic molecules are ubiquitous in the Universe. Recently, in situ spacecraft measurements and experiments suggest that amino acids can be formed abiotically on interstellar ices and comets. These amino acids could be continuously delivered by meteorite or comet impacts to icy moons. Here, we show that polymerization of organic monomers, in particular amino acids and nucleotides, could proceed spontaneously in the cold environment of icy moons, in particular the jovian icy moon Europa as a typical example, based on thermodynamic calculations, though kinetics of formation are not addressed. Observed surface temperature on Europa is 120 and 80 K in the equatorial region and polar region, respectively. At such low temperatures, Gibbs energies of polymerization become negative, and the estimated thermal structure of the icy crust should contain a shallow region (i.e., at a depth of only a few kilometers) favorable for polymerization. Investigation of the possibility of organic monomer polymerization on icy moons could provide good constraints on the origin and early evolution of extraterrestrial life. PMID:26060981

  7. Polymerization of Building Blocks of Life on Europa and Other Icy Moons

    PubMed Central

    Kitadai, Norio

    2015-01-01

    Abstract The outer Solar System may provide a potential habitat for extraterrestrial life. Remote sensing data from the Galileo spacecraft suggest that the jovian icy moons—Europa, Ganymede, and possibly Callisto—may harbor liquid water oceans underneath their icy crusts. Although compositional information required for the discussion of habitability is limited because of significantly restricted observation data, organic molecules are ubiquitous in the Universe. Recently, in situ spacecraft measurements and experiments suggest that amino acids can be formed abiotically on interstellar ices and comets. These amino acids could be continuously delivered by meteorite or comet impacts to icy moons. Here, we show that polymerization of organic monomers, in particular amino acids and nucleotides, could proceed spontaneously in the cold environment of icy moons, in particular the jovian icy moon Europa as a typical example, based on thermodynamic calculations, though kinetics of formation are not addressed. Observed surface temperature on Europa is 120 and 80 K in the equatorial region and polar region, respectively. At such low temperatures, Gibbs energies of polymerization become negative, and the estimated thermal structure of the icy crust should contain a shallow region (i.e., at a depth of only a few kilometers) favorable for polymerization. Investigation of the possibility of organic monomer polymerization on icy moons could provide good constraints on the origin and early evolution of extraterrestrial life. Key Words: Planetary science—Europa—Planetary habitability and biosignatures—Extraterrestrial life—Extraterrestrial organic compounds. Astrobiology 15, 430–441. PMID:26060981

  8. Introducing the Moon's Orbital Eccentricity

    NASA Astrophysics Data System (ADS)

    Oostra, Benjamin

    2014-11-01

    I present a novel way to introduce the lunar orbital eccentricity in introductory astronomy courses. The Moon is perhaps the clearest illustration of the general orbital elements such as inclination, ascending node, eccentricity, perigee, and so on. Furthermore, I like the students to discover astronomical phenomena for themselves, by means of a guided exercise, rather than just telling them the facts.1 The inclination and nodes may be found by direct observation, monitoring carefully the position of the Moon among the stars. Even the regression of the nodes may be discovered in this way2 To find the eccentricity from students' observations is also possible,3 but that requires considerable time and effort. if a whole class should discover it in a short time, here is a method more suitable for a one-day class or home assignment. The level I aim at is, more or less, advanced high school or first-year college students. I assume them to be acquainted with celestial coordinates and the lunar phases, and to be able to use algebra and trigonometry.

  9. Compositional Impact of Io Volcanic Emissions on Jupiter's Magnetosphere and the Icy Galilean Moons

    NASA Technical Reports Server (NTRS)

    Cooper, John; Fegley, Bruce; Lipatov, Alexander; Richardson, John; Sittler, Edward

    2011-01-01

    measured throughout the jovian magnetosphere and in the local moon environments can act as tracers if we know from direct measurements and models the distributions at the mostly likely sources, i.e. at IO. However, our knowledge of these abundances are very limited from earlier in-situ and remote measurements, mainly confined to major (S, O) and some minor (Na, K, Cl) species with abundances at or above a few percent relative to O. Future in-situ plasma measurements by the planned Jupiter Europa Orbiter and Jupiter Ganymede Orbiter missions should extend the abundance coverage to minor and even trace elemental species. For Europa astrobiological investigations it is also important to specify iogenic inputs and surface processing of isotopic species. We discuss the range of abundance distributions arising from models for IO hot volcanic emissions, and from the subsequent dynamics of ion injection, magnetospheric transport, and icy moon surface bombardment.

  10. Surfaces and exospheres of the icy Galilean moons - an integral approach

    NASA Astrophysics Data System (ADS)

    Galli, André; Wurz, Peter; Vorburger, Audrey; Tulej, Marek; Pommerol, Antoine; Scheer, Jürgen; Thomas, Nicolas; Mousis, Olivier; Barabash, Stas; Wieser, Martin; Lammer, Helmut

    2014-05-01

    The JUpiter ICy moons Explorer (JUICE) will investigate Jupiter and its system with particular emphasis on Ganymede as a planetary body and potential habitat. Europa and Callisto flybys will allow for a comparative picture of the icy Galilean moons. As part of the scientific preparation work for JUICE, we examine the requirements and expected science results related to the Neutral gas and Ion Mass spectrometer (NIM), which belongs to the Particle Environment Package on board JUICE. Models of the exosphere profiles at Europa, Ganymede, and Callisto allow us to optimize the design of NIM, but the reliability of the models is limited because the properties of icy surfaces, in particular sputtering and sublimation parameters for icy regolith mixed with carbonates or salts, are not well known. We therefore have started a series of lab experiments with icy regolith subjected to ion and UV irradiation in a cold vacuum. Currently, we perform irradiation experiments of pure water ice with H+ and O+ ions. In the coming years, we will expand the experiments to more complex cases (including UV-radiation, temperature cycles and chemical impurities such as O2, C, S, CO2, SO2, and Na) relevant for Galilean moons. The results will constrain exosphere models and will enable the scientific community to better link exosphere measurements with processes in the ice and observed surface features.

  11. A passive probe for subsurface oceans and liquid water in Jupiter's icy moons

    NASA Astrophysics Data System (ADS)

    Romero-Wolf, Andrew; Vance, Steve; Maiwald, Frank; Heggy, Essam; Ries, Paul; Liewer, Kurt

    2015-03-01

    We describe an interferometric reflectometer method for passive detection of subsurface oceans and liquid water in jovian icy moons using Jupiter's decametric radio emission (DAM). The DAM flux density exceeds 3000 times the galactic background in the neighborhood of the jovian icy moons, providing a signal that could be used for passive radio sounding. An instrument located between the icy moon and Jupiter could sample the DAM emission along with its echoes reflected in the ice layer of the target moon. Cross-correlating the direct emission with the echoes would provide a measurement of the ice shell thickness along with its dielectric properties. The interferometric reflectometer provides a simple solution to sub-jovian radio sounding of ice shells that is complementary to ice penetrating radar measurements better suited to measurements in the anti-jovian hemisphere that shadows Jupiter's strong decametric emission. The passive nature of this technique also serves as risk reduction in case of radar transmitter failure. The interferometric reflectometer could operate with electrically short antennas, thus extending ice depth measurements to lower frequencies, and potentially providing a deeper view into the ice shells of jovian moons.

  12. Energetic neutral particles detection in the environment of Jupiter's icy moons: Ganymede's and Europa's neutral imaging experiment (GENIE)

    NASA Astrophysics Data System (ADS)

    Milillo, A.; Orsini, S.; Plainaki, C.; Fierro, D.; Argan, A.; Vertolli, N.; Dandouras, I.; Leoni, R.; Liemohn, M. W.; Scheer, J.; Selci, S.; Soffitta, P.; Baragiola, R. A.; Brienza, D.; Cassidy, T. A.; Chassela, O.; Colasanti, L.; D'Alessandro, M.; Daglis, I.; De Angelis, E.; Del Monte, E.; Di Lellis, A. M.; Di Persio, G.; Fabiani, S.; Gaggero, A.; Ganushkina, N.; Garnier, P.; Gilbert, J. A.; Hansen, K. C.; Hsieh, K. C.; Lazzarotto, F.; Lepri, S. T.; Mangano, V.; Massetti, S.; Mattioli, F.; Mura, A.; Palumbo, M. E.; Rispoli, R.; Rossi, M.; Rubini, A.; Teolis, B.; Tosi, F.; Tosti, D.; Toublanc, D.

    2013-11-01

    The detection of Energetic Neutral Particles (ENP) above 10 eV can unequivocally relate a surface-bound exosphere to surface features and can monitor instantaneously the effect of plasma precipitation onto the surface. In the framework of a mission to Jupiter's moons, 2D imaging of plasma precipitation will provide important information on the plasma circulation at the orbits of the moons. Furthermore, a joint measurement of precipitating ions will permit an estimation of the efficiency of the release process. Coupled measurements of ENP and gas composition will improve our knowledge of surface release mechanisms. Ganymede's and Europa's Neutral Imaging Experiment (GENIE) is a high-angular-resolution detector, based on the ToF (Time of Flight) technique, that can detect ENP (energy range >10 eV-few keV) in the Jupiter environment thanks to an innovative design and technology. Its objective is to map the sites of origin of the ENP of the icy moons' exospheres to investigate the interaction between the surface and the environment. Finally, coupling GENIE with an ion sensor and a mass spectrometer will be an outstanding opportunity to better understand the magnetosphere-moon coupling within the Jupiter system and compare the surface interaction with plasma in the diverse moons. In this paper, the scientific objectives and requirements of ENP detection are summarized and the description of the innovative design concept of GENIE is given, together with the signal and background noise simulation.

  13. Remote Sensing of Icy Galilean Moon Surface and Atmospheric Composition Using Low Energy (1 eV-4 keV) Neutral Atom Imaging

    NASA Technical Reports Server (NTRS)

    Collier, M. R.; Sittler, E.; Chornay, D.; Cooper, J. F.; Coplan, M.; Johnson, R. E.

    2004-01-01

    We describe a low energy neutral atom imager suitable for composition measurements Europa and other icy Galilean moons in the Jovian magnetosphere. This instrument employs conversion surface technology and is sensitive to either neutrals converted to negative ions, neutrals converted to positive ions and the positive ions themselves depending on the power supply. On a mission such as the Jupiter Icy Moons Orbiter (JIMO), two back-to-back sensors would be flown with separate power supplies fitted to the neutral atom and iodneutral atom sides. This will allow both remote imaging of 1 eV < E < 4 keV neutrals from icy moon surfaces and atmospheres, and in situ measurements of ions at similar energies in the moon ionospheres and Jovian magnetospheric plasma. The instrument provides composition measurements of the neutrals and ions that enter the spectrometer with a mass resolution dependent on the time-of-flight subsystem and capable of resolving molecules. The lower energy neutrals, up to tens of eV, arise from atoms and molecules sputtered off the moon surfaces and out of the moon atmospheres by impacts of more energetic (keV to MeV) ions from the magnetosphere. Direct Simulation Monte Carlo (DSMC) models are used to convert measured neutral abundances to compositional distributions of primary and trace species in the sputtered surfaces and atmospheres. The escaping neutrals can also be detected as ions after photo- or plasma-ionization and pickup. Higher energy, keV neutrals come from charge exchange of magnetospheric ions in the moon atmospheres and provide information on atmospheric structure. At the jovicentric orbits of the icy moons the presence of toroidal gas clouds, as detected at Europa's orbit, provide M e r opportunities to analyze both the composition of neutrals and ions originating from the moon surfaces, and the characteristics of magnetospheric ions interacting with neutral cloud material. Charge exchange of low energy ions near the moons, and

  14. The radar-glory theory for icy moons with implications for radar mapping

    NASA Technical Reports Server (NTRS)

    Eshleman, Von R.

    1987-01-01

    The anomalous radar echoing properties of three ice-clad moons of Jupiter appear to be due to glory-like backscattering from buried craters. The enormous glare from these sources would impair geologic studies based on standard methods of radar mapping. It is not known whether similar or different problems will arise in the radar study of other icy surfaces in the outer solar system, or of the unseen surface of Titan. In any event, the results from the moons of Jupiter illustrate the role of exploratory measurements and the importance of possible bistatic radar-mapping techniques based on the use of separated transmitters and receivers.

  15. Inverse theory resolution analysis in planning radio science gravity investigations of icy moons

    NASA Astrophysics Data System (ADS)

    Ganse, A.; Vance, S.

    2014-12-01

    The nature of an icy satellite's interior relates fundamentally to its composition, thermal structure, formation and evolution history, and prospects for supporting life. Gravity measurements via radio Doppler information during spacecraft flybys constitute an important tool to infer gross interior structure. Liquid water and ice layers have previously been inferred for the interiors of Jupiter's icy satellites Europa, Ganymede, and Callisto on the basis of magnetic field measurements by the Galileo probe. On Europa and Callisto induced magnetic field signatures measured by the Galileo probe provided strong evidence for an ionic aqueous ocean. Among the chief goals of the proposed Europa Clipper mission in returning to Europa is characterizing the structure of the moon's icy shell. A geophysical inverse theory resolution analysis can be calculated at the pre-measurement mission planning stage, contributing planning considerations from the point of view of the search for mass anomalies in the ice shell (meteorites or diapiric upwellings) or near the H2O/rock interface (seamounts). The analysis allows us to assess the location-varying resolution of an icy moon's interior density anomaly distribution that can be estimated from radio Doppler measurements. It considers the tradeoff between the resolution of the estimated density anomaly distribution and its estimation uncertainty, and investigates issues in distinguishing between ocean anomalies (e.g., seamounts) and mass anomalies within or near the surface of the ice layer. We apply the resolution analysis to proposed Europa Clipper trajectories and past Galileo spacecraft trajectories about Europa and Ganymede.

  16. High-Power Radar Sounders for the Investigation of Jupiter Icy Moons

    NASA Technical Reports Server (NTRS)

    Safaeinili, A.; Ostro, S.; Rodriquez, E.; Blankenship, D.; Kurth, W.; Kirchner, D.

    2005-01-01

    The high power and high data rate capability made available by a Prometheus class spacecraft could significantly enhance our ability to probe the subsurface of the planets/moons and asteroid/comets. The main technology development driver for our radar is the proposed Jupiter Icy Moon Orbiter (or JIMO) mission due to its harsh radiation environment. We plan to develop a dual-band radar at 5 and 50 MHz in response to the two major science requirements identified by the JIMO Science Definition Team: studying the near subsurface (less than 2 km) at high resolution and detection of the ice/ocean interface for Europa (depth up to 30 km). The 50-MHz band is necessary to provide high spatial resolution (footprint and depth) as required by the JIMO mission science requirements as currently defined. Our preliminary assessment indicates that the 50-MHz system is not required to be as high-power as the 5-MHz system since it will be more limited by the surface clutter than the Jupiter or galactic background noise. The low frequency band (e.g. 5 MHz), which is the focus of this effort, would be necessary to mitigate the performance risks posed by the unknown subsurface structure both in terms of unknown attenuation due to volumetric scattering and also the detection of the interface through the attenuative transition region at the ice/ocean interface. Additionally, the 5-MHz band is less affected by the surface roughness that can cause loss of coherence and clutter noise. However, since the Signal-to-Noise-Ratio (SNR) of the 5-MHz radar band is reduced due to Jupiter noise when operating in the Jupiter side of the moon, it is necessary to increase the radiated power. Our challenge is to design a high-power HF radar that can hnction in Jupiter's high radiation environment, yet be able to fit into spacecraft resource constraints such as mass and thermal limits. Our effort to develop the JIMO radar sounder will rely on our team's experience with planetary radar sounder design

  17. Energetic Neutral Particles detection in the environment of Jupiter's icy moons: Ganymede's and Europa's Neutral Imaging Experiment (GENIE)

    NASA Astrophysics Data System (ADS)

    Milillo, Anna; Orsini, Stefano; Plainaki, Christina; Fierro, Davide; Argan, Andrea; Vertolli, Nello; Dandouras, Iannis; Leoni, Roberto; Liemohn, Michael; Scheer, Jurgen; Selci, Stefano; Soffitta, Paolo

    2013-04-01

    The detection of Energetic Neutral Particles (ENP) above 10 eV can univocally relate a surface-bound exosphere to surface features and to monitor instantaneously the effect of plasma precipitation onto the surface. The 2D imaging of plasma precipitation will provide important information on the plasma circulation at the orbits of the moons. Furthermore, a joint measurement of precipitating ions will permit an estimation the efficiency of the release process. Coupled measurements of ENP and gas composition will improve our knowledge of surface release mechanisms. GENIE (Ganymede Europa Neutral Imaging Experiment) is a high-angular-resolution detector, based on the ToF (Time of Flight) technique able to detect ENP (energy range 10 eV - few keV) in the Jupiter environment thanks to an innovative design and technology. Its objective is to map the sites of origin of the ENP of the icy moons' exospheres, to investigate the interaction between the surface and the environment. Finally, GENIE jointly with an ion-sensor and a mass spectrometer in the JUICE mission will be an outstanding opportunity to better understand also the magnetosphere-moon coupling within the Jupiter's system. In particular, a comparison between the surface interaction with the intense radiation at Europa and with the plasma shielding by the internal magnetic field at Ganymede, will provide a unique opportunity to investigate different surface evolution scenarios of Jupiter's moons.

  18. Cosmic ion bombardment of the icy moons of Jupiter

    NASA Astrophysics Data System (ADS)

    Strazzulla, G.

    2011-05-01

    A large number of experiments have been performed in many laboratories in the world with the aim to investigate the physico-chemical effects induced by fast ions irradiating astrophysical relevant materials. The laboratory in Catania (Italy) has given a contribution to some experimental works. In this paper I review the results of two class of experiments performed by the Catania group, namely implantation of reactive (H+, C+, N+, O+ and S+) ions in ices and the ion irradiation induced synthesis of molecules at the interface between water ice and carbonaceous or sulfurous solid materials. The results, discussed in the light of some questions concerning the surfaces of the Galilean moons, contribute to understand whether minor molecular species (CO2, SO2, H2SO4, etc.) observed on those objects are endogenic i.e. native from the satellite or are produced by exogenic processes, such as ion implantation.The results indicate that:C-ion implantation is not the dominant formation mechanism of CO2 on Europa, Ganimede and Callisto.Implantation of sulfur ions into water ice produces hydrated sulfuric acid with high efficiency such to give a very important contribution to the sulfur cycle on the surface of Europa and other satellites.Implantation of protons into carbon dioxide produces some species containing the projectile (H2CO3, and O-H in poly-water).Implantation of protons into sulfur dioxide produces SO3, polymers, and O3 but not H-S bonds.Water ice has been deposited on refractory carbonaceous materials: a general finding is the formation of a noteworthy quantity of CO2. We suggest that this is the primary mechanism to explain the presence of carbon dioxide on the surfaces of the Galilean satellites.Water ice has been deposited on refractory sulfurous materials originating from SO2 or H2S irradiation. No evidence for an efficient synthesis of SO2 has been found.

  19. Mission Techniques for Exploring Saturn's icy moons Titan and Enceladus

    NASA Astrophysics Data System (ADS)

    Reh, Kim; Coustenis, Athena; Lunine, Jonathan; Matson, Dennis; Lebreton, Jean-Pierre; Vargas, Andre; Beauchamp, Pat; Spilker, Tom; Strange, Nathan; Elliott, John

    2010-05-01

    The future exploration of Titan is of high priority for the solar system exploration community as recommended by the 2003 National Research Council (NRC) Decadal Survey [1] and ESA's Cosmic Vision Program themes. Cassini-Huygens discoveries continue to emphasize that Titan is a complex world with very many Earth-like features. Titan has a dense, nitrogen atmosphere, an active climate and meteorological cycles where conditions are such that the working fluid, methane, plays the role that water does on Earth. Titan's surface, with lakes and seas, broad river valleys, sand dunes and mountains was formed by processes like those that have shaped the Earth. Supporting this panoply of Earth-like processes is an ice crust that floats atop what might be a liquid water ocean. Furthermore, Titan is rich in very many different organic compounds—more so than any place in the solar system, except Earth. The Titan Saturn System Mission (TSSM) concept that followed the 2007 TandEM ESA CV proposal [2] and the 2007 Titan Explorer NASA Flagship study [3], was examined [4,5] and prioritized by NASA and ESA in February 2009 as a mission to follow the Europa Jupiter System Mission. The TSSM study, like others before it, again concluded that an orbiter, a montgolfiѐre hot-air balloon and a surface package (e.g. lake lander, Geosaucer (instrumented heat shield), …) are very high priority elements for any future mission to Titan. Such missions could be conceived as Flagship/Cosmic Vision L-Class or as individual smaller missions that could possibly fit within NASA's New Frontiers or ESA's Cosmic Vision M-Class budgets. As a result of a multitude of Titan mission studies, several mission concepts have been developed that potentially fit within various cost classes. Also, a clear blueprint has been laid out for early efforts critical toward reducing the risks inherent in such missions. The purpose of this paper is to provide a brief overview of potential Titan (and Enceladus) mission

  20. Lunar Orbiter Photographic Atlas of the Moon

    NASA Technical Reports Server (NTRS)

    Bowker, D. E.; Hughes, J. K.

    1971-01-01

    A selection of the reconstructed photographs taken during 1966 and 1967 by five Lunar Orbiters is presented. The selection provides essentially complete coverage of the near and far sides of the moon in detail. The photographs were reprocessed from the original video data tapes.

  1. Discovering New Compounds on Icy Moon Surfaces with Mid-Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Young, C. L.; Wray, J. J.; Hand, K. P.; Poston, M.; Carlson, R. W.; Clark, R. N.; Spencer, J. R.; Jennings, D. E.

    2015-12-01

    Spectroscopy of icy satellite surfaces can aid us in understanding sources and sinks of material in the outer solar system. The spectral complexity of the Saturnian satellite system as seen in reflected sunlight suggests additional complexity may be present at mid-infrared wavelengths from which unique compositional information can be gleaned [1]. Yet to date, Cassini Composite Infrared Spectrometer (CIRS) surface compositional studies have received little attention. We are investigating the value of mid-infrared spectroscopy for identifying non-H2O constituents of icy moon surfaces. On Iapetus' dark terrain, we find an emissivity feature at ~855 cm-1 and a possible doublet at 660 and 690 cm-1 that do not correspond to any known instrument artifacts [2]. We attribute the 855 cm-1feature to fine-grained silicates, similar to those found in dust on Mars and in meteorites, which are nearly featureless at shorter wavelengths [3]. Silicates on the dark terrains of Saturn's icy moons have been suspected for decades, but there have been no definitive detections until now. Because peaks can shift depending on temperature, pressure, and grain size, measurements at Iapetus-like conditions are necessary for more positive feature identifications [e.g., 4]. We measured the vacuum (P<3x10-8 torr) and low temperature (125 K) mid-infrared spectra of various fine-grained powdered silicates. We find that some of these materials do have emissivity features near 855 cm-1and match the doublet. Identifying a specific silicate would provide clues into the origin and implications of the dark material in the Saturnian system. We also report on our ongoing exploration of the CIRS icy moon dataset and plans for additional future measurements in JPL's Icy Worlds Simulation Lab. [1] Flasar, F. M., et al. (2004), Space Sci Rev, 115, 169. [2] Young, C.L., et al. (in review), ApJ Lett. [3] Christensen, P. R., et al. (2004), Sci, 306, 1733. [4] Wray, J. J., et al. (2014), DPS 46th Meeting, Vol. 46.

  2. Identifying new surface constituents of icy moons using mid-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Young, Cindy L.; Wray, James J.; Hand, Kevin P.; Poston, Michael J.; Carlson, Robert W.; Clark, Roger N.; Spencer, John R.; Jennings, Donald E.

    2015-11-01

    Spectroscopic compositional studies of the icy satellites can help us to better understand the formation and evolution of material in the outer solar system. The spectral complexity of the Saturnian satellite system as seen in reflected visible light suggests additional complexity may be present at mid-infrared wavelengths from which unique compositional information can be gleaned [1]. In addition, the mid-infrared is the region of the stronger fundamental diagnostic vibrational modes of many compounds. However, Cassini Composite Infrared Spectrometer (CIRS) surface compositional studies have received little attention to date.We are exploring the suitability of mid-infrared spectroscopy for discovering non-H2O compounds on icy moon surfaces. On the dark terrain of Iapetus, we find an emissivity feature at ~855 cm-1 and a potential doublet at 660 and 690 cm-1 that do not correspond to any known instrument artifacts [2]. We attribute the 855 cm-1 feature to fine-grained silicates, similar to those found in dust on Mars and in meteorites, which are nearly featureless at shorter wavelengths [3]. Although silicates on the dark terrains of Saturn’s icy moons have been suspected for decades, there have been no definitive prior detections. Serpentines measured at ambient conditions have features near 855 cm-1 and 660 cm-1 [4]. However, peaks can shift depending on temperature, pressure, and grain size, so measurements at Iapetus-like conditions are necessary for more positive identifications [e.g., 5].We measured the vacuum, low temperature (125 K) spectra of various fine-grained powdered silicates. We find that some of these materials do have emissivity features near 855 cm-1 and match the doublet. Identifying a specific silicate would provide clues into the sources and sinks of the dark material in the Saturnian system. We report on our ongoing exploration of the CIRS icy moon dataset and plans for future measurements in JPL’s Icy Worlds Simulation Lab.[1] Flasar, F

  3. Orbit determination and control for the European Student Moon Orbiter

    NASA Astrophysics Data System (ADS)

    Zuiani, Federico; Gibbings, Alison; Vetrisano, Massimo; Rizzi, Francesco; Martinez, Cesar; Vasile, Massimiliano

    2012-10-01

    This paper presents the preliminary navigation and orbit determination analyses for the European Student Moon Orbiter. The severe constraint on the total mission Δv and the all-day piggy-back launch requirement imposed by the limited available budget, led to the choice of using a low-energy transfer, more specifically a Weak Stability Boundary one, with a capture into an elliptic orbit around the Moon. A particular navigation strategy was devised to ensure capture and fulfil the requirement for the uncontrolled orbit stability at the Moon. This paper presents a simulation of the orbit determination process, based on an extended Kalman filter, and the navigation strategy applied to the baseline transfer of the 2011-2012 window. The navigation strategy optimally allocates multiple Trajectory Correction Manoeuvres to target a so-called capture corridor. The capture corridor is defined, at each point along the transfer, by back-propagating the set of perturbed states at the Moon that provides an acceptable lifetime of the lunar orbit.

  4. Cassini finds an oxygen-carbon dioxide atmosphere at Saturn's icy moon Rhea.

    PubMed

    Teolis, B D; Jones, G H; Miles, P F; Tokar, R L; Magee, B A; Waite, J H; Roussos, E; Young, D T; Crary, F J; Coates, A J; Johnson, R E; Tseng, W-L; Baragiola, R A

    2010-12-24

    The flyby measurements of the Cassini spacecraft at Saturn's moon Rhea reveal a tenuous oxygen (O(2))-carbon dioxide (CO(2)) atmosphere. The atmosphere appears to be sustained by chemical decomposition of the surface water ice under irradiation from Saturn's magnetospheric plasma. This in situ detection of an oxidizing atmosphere is consistent with remote observations of other icy bodies, such as Jupiter's moons Europa and Ganymede, and suggestive of a reservoir of radiolytic O(2) locked within Rhea's ice. The presence of CO(2) suggests radiolysis reactions between surface oxidants and organics or sputtering and/or outgassing of CO(2) endogenic to Rhea's ice. Observations of outflowing positive and negative ions give evidence for pickup ionization as a major atmospheric loss mechanism. PMID:21109635

  5. Onset of convection and differentiation in the hydrated cores of icy moons.

    NASA Astrophysics Data System (ADS)

    Sotin, Christophe; Reynard, Bruno

    2013-04-01

    The Galileo mission to Jupiter and the Cassini/Huygens mission to Saturn have revealed that the three large Jovian icy moons and Titan, Saturn's largest satellite, are at least partly differentiated. Their normalized moments of inertia are smaller than 2/5, which is the value for undifferentiated moons. We present new simulations of the thermal evolution, dehydration process, differentiation, and onset of convection in the hydrated cores of large icy satellites. The motivation is to investigate whether convection can start before dehydration starts in the cores. Such a process would prevent differentiation. The viscosity of antigorite, the hydrated silicate supposed to compose the hydrated cores, is strongly non-Newtonian and weakly temperature-dependent. The cores are volumetrically heated by natural radioactivity. We have adapted the theory developed for non-Newtonian fluids heated from below [1] to the case of volumetrically heated fluids. A recent review [2] of the physical parameters relevant to the thermal evolution of hydrated cores made of antigorite provides values quite different from those used in previous studies [3,4], which seriously modifies the results of previous simulations including the predicted present interior structure of the large icy satellites. The numerical simulations presented in this study suggest that the inner part of the hydrated core of icy moons would dehydrate for a large range of parameters, the most important of which is the amount of 40K. The outer core would remain hydrated. It is shown that convection could start in the outer core for large values of internal heating. Implications for subsequent thermal evolution are being investigated. [1] Solomatov V.S. (1995) Scaling of temperature and stressdependent viscosity convection; Phys. Fluids 7, 266; doi: 10.1063/1.868624. [2] Reynard B. (2012) Serpentine in active subduction zones. Lithos, doi: 10.1016/j.lithos.2012.10.012 [3] Grinrod P.M., A.D. Fortes, F. Nimmo, D.L. Feltham

  6. Constraints on the nanoscale minerals on the surface of Saturnian icy moons

    NASA Astrophysics Data System (ADS)

    Srama, R.; Hsu, H.; Kempf, S.; Horanyi, M.

    2011-12-01

    Nano-phase iron particles embedded into the surfaces of Saturn's icy moons as well as in the ring material have been proposed to explain the infrared spectra obtained by Cassini VIMS. Because the continuous influx of interplanetary fast impactors into the Saturnian system erodes any exposed surface, a certain amount of the embedded nano-particles will be ejected into the Saturnian magnetosphere and speed up to velocities high enough to be detected by the Cassini dust detector CDA. Thus, the analysis of the so-called stream particles provides constraints on the amount and the composition of any nano-phase material within the surfaces of the icy moons. Nanoparticles registered by the Cassini dust detector are most likely composed of silica (SiO2). Their dynamical properties indicate that they are relics of E ring dust grains. In this talk we will show that the Cassini stream particle measurements provide strong constraints for the composition and size distribution of any embedded nano-material.

  7. Compositional Diversity of Small Icy Objects Beyond Saturn's Orbit

    NASA Astrophysics Data System (ADS)

    Grundy, W. M.

    2006-05-01

    This talk will review what observations are revealing about compositions of the diverse zoo of icy bodies beyond Saturn's orbit. The primary tool to investigate their compositions has been near-infrared reflectance spectroscopy of their surfaces, benefiting from vibrational absorption bands in many cryogenic outer solar system materials. This technique has led to numerous important discoveries, including H2O ice on the surfaces of satellites of Uranus, Neptune, and Pluto; CH4 and N2 ices on the surfaces of Pluto and Triton; CH4 on the surfaces of the new icy planets 2005~FY9 and 2003~UB313; CO2 ice on the surfaces of Triton and uranian satellites; CO ice on the surfaces of Triton and Pluto; and water ice on the surfaces of a number of trans-neptunian objects (TNOs) and Centaurs. Additional tantalizing evidence for more complex organic ices has been seen in several TNO spectra, and evidence is widespread for very complex organic residues (tholins) which produce characteristic reddish slopes in visible wavelength spectra of almost all outer solar system objects. Spectroscopic observations can also constrain thermodynamic properties, such as between various crystalline and amorphous states, between ices mixed at macroscopic or molecular levels, and between ices at different temperatures. Quantitative estimates of ice abundances are also possible. However, reflectance spectroscopy does have significant limitations, which will be discussed. Needs for additional laboratory studies in support of future observations will also be mentioned, including those of NASA's New Horizons mission to Pluto and the Kuiper belt. In addition to spectroscopic techniques, other, somewhat less direct techniques have bearing on compositions of outer solar system objects, including measurements of densities by means of independent mass and size estimates, of atmospheres using occultation studies, and of albedos via combined thermal emission and visible reflectance photometry. These studies

  8. Distant retrograde orbits for the Moon's exploration

    NASA Astrophysics Data System (ADS)

    Sidorenko, Vladislav

    We discuss the properties of the distant retrograde orbits (which are called quasi-satellite orbits also) around Moon. For the first time the distant retrograde orbits were described by J.Jackson in studies on restricted three body problem at the beginning of 20th century [1]. In the synodic (rotating) reference frame distant retrograde orbit looks like an ellipse whose center is slowly drifting in the vicinity of minor primary body while in the inertial reference frame the third body is orbiting the major primary body. Although being away the Hill sphere the third body permanently stays close enough to the minor primary. Due to this reason the distant retrograde orbits are called “quasi-satellite” orbits (QS-orbits) too. Several asteroids in solar system are in a QS-orbit with respect to one of the planet. As an example we can mention the asteroid 2002VE68 which circumnavigates Venus [2]. Attention of specialists in space flight mechanics was attracted to QS-orbits after the publications of NASA technical reports devoted to periodic moon orbits [3,4]. Moving in QS-orbit the SC remains permanently (or at least for long enough time) in the vicinity of small celestial body even in the case when the Hill sphere lies beneath the surface of the body. The properties of the QS-orbit can be studied using the averaging of the motion equations [5,6,7]. From the theoretical point of view it is a specific case of 1:1 mean motion resonance. The integrals of the averaged equations become the parameters defining the secular evolution of the QS-orbit. If the trajectory is robust enough to small perturbations in the simplified problem (i.e., restricted three body problem) it may correspond to long-term stability of the real-world orbit. Our investigations demonstrate that under the proper choice of the initial conditions the QS-orbits don’t escape from Moon or don’t impact Moon for long enough time. These orbits can be recommended as a convenient technique for the large

  9. Measuring the Moon's orbit using a hand-held camera

    NASA Astrophysics Data System (ADS)

    Oostra, Benjamin

    2014-04-01

    This paper describes a way to measure the Moon's distance and orbital eccentricity using a digital camera. The method consists of taking photographs of the Moon and measuring the size of the lunar disk in each picture. On a series of images taken on the same night, the effect of the Earth's size is evident and thus the distance to the Moon can be computed. A larger series of images, covering several weeks, demonstrates that the Moon's orbit is not perfectly circular.

  10. JUpiter ICy moons Explorer (juice): AN ESA L-Class Mission Candidate to the Jupiter System

    NASA Astrophysics Data System (ADS)

    Dougherty, M. K.; Grasset, O.; Erd, C.; Titov, D.; Bunce, E. J.; Coustenis, A.; Blanc, M.; Coates, A. J.; Drossart, P.; Fletcher, L.; Hussmann, H.; Jaumann, R.; Krupp, N.; Prieto-Ballesteros, O.; Tortora, P.; Tosi, F.; Van Hoolst, T.

    2012-04-01

    the first subsurface observations of this icy moon, including the first determination of the minimal thickness of the icy crust over the most recently active regions. JUICE will determine the characteristics of liquid-water oceans below the icy surfaces of the moons. This will lead to an understanding of the possible sources and cycling of chemical and thermal energy, allow investigation of the evolution and chemical composition of the surfaces and of the subsurface oceans, and enable an evaluation of the processes that have affected the satellites and their environments through time. The study of the diversity of the satellite system will be enhanced with additional information gathered remotely on Io and smaller moons. The mis-sion will also focus on characterising the diversity of processes in the Jupiter system which may be required in order to provide a stable environment at Ganymede, Europa and Callisto on geologic time scales, including gravitational coupling between the Galilean satellites and their long term tidal influence on the system as a whole. Focused stud-ies of Jupiter's atmosphere, and magnetosphere and their interaction with the Galilean satellites will further enhance our understanding of the evolution and dynamics of the Jovian system. The circulation, meteorology, chemistry and structure of Jupiter will be studied from the cloud tops to the thermosphere. These observations will be attained over a sufficiently long temporal baseline with broad latitudinal coverage to investigate evolving weather systems and the mechanisms of transporting energy, momentum and material between the different layers. The focus in Jupiter's magnetosphere will include an investigation of the three dimensional properties of the magnetodisc and in-depth study of the coupling processes within the magnetosphere, ionosphere and thermosphere. Aurora and radio emissions and their response to the solar wind will be elucidated.

  11. SELENE: The Moon-Orbiting Observatory Mission

    NASA Astrophysics Data System (ADS)

    Mizutani, H.; Kato, M.; Sasaki, S.; Iijima, Y.; Tanaka, K.; Takizawa, Y.

    The Moon-orbiting SELENE (Selenological and Engineering Explorer) mission is prepared in Japan for lunar science and technology development. The launch target has been changed from 2005 to 2006 because of the launch failure of H2A rocket in 2003. The spacecraft consists of a main orbiting satellite at about 100 km altitude in the polar orbit and two sub-satellites in the elliptical orbits. The scientific objectives of the mission are; 1) study of the origin and evolution of the Moon, 2) in-situ measurement of the lunar environment, and 3) observation of the solar-terrestrial plasma environment. SELENE carries the instruments for scientific investigation, including mapping of lunar topography and surface composition, measurement of the gravity and magnetic fields, and observation of lunar and solar-terrestrial plasma environment. The total mass of scientific payload is about 300 kg. The mission period will be 1 year. If extra fuel is available, the mission will be extended in a lower orbit around 50 km. The elemental abundances are measured by x-ray and gamma-ray spectrometers. Alpha particles from the radon gas and polonium are detected by an alpha particle spectrometer. The mineralogical abundance is characterized by a multi-band imager. The mineralogical composition is identified by a spectral profiler which is a continuous spectral analyzer. The surface topographic data are obtained by a high resolution terrain camera and a laser altimeter. The inside structure up to 5 km below the lunar surface is observed by the radar sounder experiment using a 5 MHz radio wave. A magnetometer and an electron reflectometer provides data on the lunar surface magnetic field. Doppler tracking of the orbiter via the sub-satellite when the orbiter is in the far side is used to determine the gravity field of the far side. Radio sources on the two sub-satellites are used to conduct differential VLBI observation from the ground stations. The lunar environment of high energy particles

  12. IR reflectance spectroscopy of carbon dioxide clathrate hydrates. Implications for Saturn's icy moons.

    NASA Astrophysics Data System (ADS)

    Oancea, A.; Grasset, O.; Le Menn, E.; Bezacier, L.; Bollengier, O.; Le Mouélic, S.; Tobie, G.

    2012-04-01

    A CO2 spectral band was discovered by VIMS on the Saturn's satellites Dione, Hyperion, Iapetus and Phoebe [1]. The band position on the three first satellites corresponds to CO2 trapped in a complex material, but no indication exists whether this latter is water ice or some mineral or complex organic compound [1]. On Phoebe, the CO2 spectral band is consistent with solid CO2 or CO2 molecules trapped in the small cages of a clathrate hydrate structure [2]. It is thought that clathrate hydrates could play a significant role in the chemistry of the solar nebula [3] and in the physical evolution of astrophysical objects [4]. But so far, no clathrate hydrate structure has been observed in astrophysical environments. Moreover, identification of molecules trapped in a clathrate hydrate structure is extremely difficult because of the strong IR vibration modes of the water ice matrix. In this work, experimental IR reflectance spectra for CO2 clathrate hydrates are studied on grains and films. Clathrates are synthesized in a high pressure autoclave at low temperatures. IR spectral analysis is made with a low pressure and low temperature cryostat. These experimental conditions - 80 < T < 110 K, P~10-5 bar - are relevant to icy moons' surfaces. We have observed that the IR reflectance, in the spectral region (3 - 5 μm) characterized by H2O and CO2 high absorption coefficients, is strongly dependent on physical (size, surface) and optical (n and k) properties of the samples. The impact of these parameters on the CO2 clathrate IR reflectance spectrum will be presented. A comparison between the absorption bands of CO2 clathrate hydrates obtained in our lab and CO2 absorption bands as detected by VIMS on the icy satellites of Saturn will be shown. This experimental work confirms that VIMS data are not consistent with the presence of structure I CO2 clathrate hydrates on the surface of the icy moons. Possibility of having metastable structure II still remains unsolved and will be

  13. Ionization chemistry in the H2O-dominant atmospheres of the icy moons

    NASA Astrophysics Data System (ADS)

    Shematovich, V. I.; Johnson, R. E.

    2007-08-01

    The main pathways of the ionization chemistry for pure H2O- and mixed H2O+O2+CO2+NH3+CH4 atmospheres which are representative for neutral and ionized atmospheres of the icy bodies in the Jovian and Saturnian systems are discussed. The gaseous envelopes of the icy moons of the giant planets are formed usually due to the surface radiolysis by the solar UV radiation and energetic magnetospheric plasma (Johnson, 1990). The standard astrochemical UMIST2005 (UDFA05) network is used to infer the main chemical pathways of ionization chemistry in the pure or with admixtures of other volatile molecules water vapor atmospheres. In case of the H2O- dominant atmosphere the parent H2O molecules are easily dissociated and ionized by the solar UVradiation and the energetic magnetospheric electrons. These impact processes result in the formation of the secondary neutral and ionized products - chemically active radicals O and OH, and H+, H2+, O+, OH+, and H2O+ ions. Secondary ions have admixture abundances in the H2O-dominant atmospheres, because they are efficiently transformed to H3O+ hydroxonium ions in the fast ion-molecular reactions. The major H3O+ hydroxonium ion does not chemically interact with other neutrals, and is destroyed in the dissociative recombination with thermal electrons mainly reproducing the chemically simple H, H2, O, and OH species. In case of the mixed H2O+O2-dominant atmosphere corresponding to the near-surface atmospheres of icy moons (Shematovich et al., 2005), the ionization chemistry results in the formation of the second major ion O2+ - because ion of molecular oxygen has the lower ionization potential comparing with other parent species -H2, H2O, CO2. The H+, O+, OH+, and H2O+ ions can be easily converted to O2+ ions through the ion-molecular reactions. In case of significant admixture of molecular hydrogen it is possible to transfer the O2+ ions to the O2H+ ions through the fast reaction with H2 and further to the H3O+ ions through the ion

  14. Laboratory Infrared Spectroscopy to Identify New Compounds on Icy Moon Surfaces

    NASA Astrophysics Data System (ADS)

    Wray, James J.; Young, Cindy L.; Hand, Kevin P.; Poston, Michael J.; Carlson, Robert W.; Clark, Roger N.; Spencer, John R.; Jennings, Donald E.

    2014-11-01

    We are exploring the value of mid-infrared spectroscopy for identifying non-H2O constituents of icy moon surfaces. Recently we reported evidence for a new emissivity feature identified on Iapetus using Cassini’s Composite Infrared Spectrometer [1]. This 11.7 μm feature is consistent with emissivity minima (transparency features) of very fine-grained silicates. Its position and shape may be diagnostic of silicate type, but most lab data at these wavelengths have been acquired using coarser grains and/or at Earth surface pressures and temperatures. Infrared spectra can change substantially under low-temperature, vacuum conditions [e.g., 2,3].We prepared sieved (<0.4 mm) and very fine-grained (few μm) powders of six different silicates and measured their VNIR (0.35-2.5 μm) reflectance spectra under ambient air, and mid-IR (1.2-20 μm) spectra in a purged N2 glovebox. All silicates exhibited mid-IR transparency features (and loss of other features) in micronized form that were not observed for the coarser grain sizes. Muscovite, a phyllosilicate mineral possibly similar to those tentatively identified on Europa [4], provided the closest match to Iapetus in the mid-IR--although clear VNIR features of muscovite have not been identified on Iapetus [5]--and therefore we measured muscovite across the same wavelength range under Iapetus-like conditions (T=125 K, P<3x10^-8 torr). We will report on our ongoing analysis and plans for additional future measurements in JPL’s Icy Worlds Simulation Lab. [1] Young, C.L., et al. (2014), Workshop on the Habitability of Icy Worlds, Abstract #4038.[2] Logan, L.M., et al. (1973), J. Geophys. Res., 78(23), 4983-5003.[3] Donaldson Hanna, K.L., et al. (2012), J. Geophys. Res., 117, E00H05.[4] Shirley, J.H., et al. (2013), AGU Fall Meeting, Abstract #P54A-07.[5] Clark, R.N., et al. (2012), Icarus, 218, 831-860.

  15. Dielectric characterization of ice/MgSO4ṡ11H2O mixtures as Jovian icy moon crust analogues

    NASA Astrophysics Data System (ADS)

    Pettinelli, Elena; Lauro, Sebastian Emanuel; Cosciotti, Barbara; Mattei, Elisabetta; Di Paolo, Federico; Vannaroni, Giuliano

    2016-04-01

    One of the main objectives of proposed missions to the icy Jovian moons is to prove the existence of the postulated subsurface ocean on Europa using radar sounders. The success of these missions will rely on the ability of the radar signals to penetrate ten kilometers of icy material that could potentially contain various types of impurities. In this work we quantify the impact of magnesium sulfate hydrates on the electrical properties of water ice by performing a series of dielectric measurements on different ice/MgSO4ṡ11H2O mixtures as a function of frequency and at temperatures comparable with those expected on the icy satellite surfaces. Our results indicate that the salt only affects the real part of permittivity of the mixtures, whereas the imaginary part, hence the attenuation, does not significantly differ from that of pure ice. This means that in some regions signal penetration may be better than previously thought.

  16. Opposition Surges on Icy Moons: Observations by Cassini VIMS and ISS between 0.2 and five microns

    NASA Astrophysics Data System (ADS)

    Buratti, Bonnie; Dalba, Paul; Brown, Robert; Clark, Roger; Hillier, John; Mosher, Joel; Baines, Kevin; Nicholson, Phillip

    2013-04-01

    The opposition effect is the surge in brightness that most airless bodies exhibit as they become fully illuminated to an observer. Important information about the physical nature of the surface, including the constituent particle sizes and their size distribution, the compaction state of the upper regolith, and composition are embedded in the effect. Models that describe the surge in terms of physical parameters have been developed during recent decades. The acquisition of "true opposition" is rare and fleeting (and for objects in inclined orbits, nearly unattainable), so testing and application of the models has been hampered. During the 9 years of the Cassini-Huygens mission, a wealth of data at and near opposition has been collected for the 6 main icy satellites of Saturn: Mimas, Enceladus, Tethys, Dione, Rhea, and Iapetus, including some recently obtained key data for Enceladus and Mimas. Furthermore, the combined spectral range of the Imaging Science Subsystem (ISS) and Visible Infrared Mapping Spectrometer (VIMS) cameras spans 0.20-5.1 microns, which includes many spectral regions not observable from the ground. This extraordinary coverage in solar phase angle and in spectral range provides in essence a laboratory in which to test models of the opposition effect. Although these moons are bright in the visible region, where multiple scattering complicates the modeling, they are dark in many regions of the infrared, enabling a more robust analysis. Some satellites have data for both leading and trailing sides, allowing an investigation of alteration effects such as meteoritic and magnetospheric bombardment and accretion of E-ring particles. Small particles accreted onto their surfaces from the E-ring appear to become "invisible" at the longer wavelengths. All of the moons exhibit a very steep curve at solar phase angles less than one degree, suggesting that coherent backscatter is present. However, this "supersurge" is present even at wavelengths where there is

  17. Contingency and recovery options for the European Student Moon Orbiter

    NASA Astrophysics Data System (ADS)

    van der Weg, Willem Johan; Vasile, Massimiliano

    2014-01-01

    This paper presents an overview of the analysis performed on the lunar orbit and some of the possible contingencies for the European Student Moon Orbiter (ESMO). Originally scheduled for launch in 2014 -2015 as a piggyback payload, it was the only ESA planned mission to the Moon. By way of a weak stability boundary transfer, ESMO is inserted into an orbit around the Moon. Propellant use is at a premium, so the operational orbit is selected to be highly eccentric. In addition, an optimization is presented to achieve an orbit that is stable for 6 months without requiring orbit maintenance. A parameter study is undertaken to study the sensitivity of the lunar orbit insertion. A database of transfer solutions across 2014 and 2015 is used to study the relation between the robustness of weak capture and the planetary geometry at lunar arrival. A number of example recovery scenarios, where the orbit insertion maneuver partially or completely fails, are also considered.

  18. Theoretical studies of the radar properties of the icy Galilean moons of Jupiter

    NASA Technical Reports Server (NTRS)

    Eshleman, Von R.

    1993-01-01

    The icy Galilean satellites of Jupiter - Europa, Ganymede, and Callisto - have unusual radar scattering properties compared with those of the terrestrial planets or Earth's Moon. There are three main features of the data that distinguish these targets: (1) the radar cross-section normalized by the geometrical cross-section is an order of magnitude larger than that of any terrestrial planet; (2) the reflected power is almost evenly distributed between two orthogonal polarizations with more power being returned in the same circular polarization as was transmitted whereas virtually all of the power returned from the terrestrial planets is contained in the opposite circular polarization to the one that was transmitted; and (3) the echo power spectra have a broad shape indicating a nearly uniformly radar-bright surface in contrast to the spectra from the terrestrial planets that contain a strong quasi-specular component from the vicinity of the sub-radar point and very little reflected power from the rest of the surface. The normalized radar cross-sections decrease as the areal water ice coverage decreases from Europa to Ganymede to Callisto. Recently, radar echoes from the polar caps of Mars and Mercury, and from Saturn's satellite Titan imply similarly strong cross-sections and have classically unexpected polarization properties and it is also thought that this is due to the presence of ice on the surface. A model called the radar glory model is analyzed and it is shown that the main features of the radar echoes calculated from this model agree well with the observations from all three icy Galilean satellites. This model involves long radar paths in the ice below the surface and special structures in which the refractive index decreases abruptly at a hemispherical boundary. It is not known whether such structures exist or how they could be created, but possible scenarios can be imagined such as the formation of an impact crater followed by deposition of a frost layer

  19. A New Moon: Improved Lunar Orbiter Mosaics

    NASA Astrophysics Data System (ADS)

    Byrne, Charles J.

    2002-01-01

    Photographs of the five Lunar Orbiter missions in 1965 and 1966 provide comprehensive coverage of the moon at resolutions in the range of about 1 meter to 300 meters. With a few exceptions, they are taken at a moderately low sun angle to clearly show the topography. These photos, especially the set edited by Bowker and Hughes, are still in active use in books, papers, and slide presentations and they are likely to be used in planning the missions of future lunar spacecraft. Scanning artifacts (sometimes called the 'venetian blind effect') detract from the visual quality of the photographs, particularly when they are printed at high contrast to show albedo variations such as rays or subtle topology features such as the margins of lava flows. The author has written a program to estimate and remove the artifacts from the pictures, greatly improving their cosmetic quality. The program detects lines between framelets of a mosaic, removes the lines caused by light leaking between framelets, estimates the systematic streaks caused by cathode ray tube scanning in the spacecraft and the Ground Reconstruction Equipment, and compensates for these streaks. Non-linearity introduced by contrast enhancement in the production of the input photos is considered in the compensation process.

  20. Icy moon exospheres: the interface between Jovian environment and satellite surfaces as a key scientific target for JUICE

    NASA Astrophysics Data System (ADS)

    Plainaki, Christina; Milillo, Anna; Grassi, Davide; Mura, Alessandro; Massetti, Stefano; Orsini, Stefano; Mangano, Valeria; De Angelis, Elisabetta; Rispoli, Rosanna

    2016-04-01

    The exospheres of Jupiter's icy satellites -often referred to as tenuous atmospheres- represent the actual interface between the surfaces of these moons and the giant planet's environment. In this perspective, their characterization is of key importance to achieve a fully understanding of the alteration processes induced on the icy surfaces by the radiation environment. Therefore, a full interpretation of the surface data and a thorough understanding of the surface evolution history, have as a necessary prerequisite the accurate determination of the role of the exospheres in the interactions between the icy moons and the Jupiter's magnetospheric environment. Moreover, in order to understand the mass and energy exchange between satellites and Jovian environment, the detailed characterization of the exosphere as a boundary region between the moon and the giant planet's magnetosphere, is fundamental. In this paper, we show that the achievement of the science objectives of the JUICE mission related to the icy satellites exospheres will be feasible only through an interdisciplinary approach characterized by coordinated observation scenarios and joint campaigns in payload operations. It is evidenced that it is of key importance to measure - in the larger possible extent - the following quantities: density of neutral species; density of ionosphere and charged particles fluxes; efficiency of interactions of the exosphere with particle and photon radiation fields. Through the planning of potential synergies between different datasets to be obtained during different mission phases, the current paper aims to contribute to the achievement of both of the JUICE mission's Key Science Goals, i.e. 1) the characterization of Ganymede, Europa and Callisto as planetary objects and potential habitats and 2) the exploration of the Jupiter system as an archetype for gas giants. The suggested planning for joint observations by different JUICE payload instruments could be extended later in

  1. Fitting Orbits to Jupiter's Moons with a Spreadsheet.

    ERIC Educational Resources Information Center

    Bridges, Richard

    1995-01-01

    Describes how a spreadsheet is used to fit a circular orbit model to observations of Jupiter's moons made with a small telescope. Kepler's Third Law and the inverse square law of gravity are observed. (AIM)

  2. Determining the eccentricity of the Moon's orbit without a telescope

    NASA Astrophysics Data System (ADS)

    Krisciunas, Kevin

    2010-08-01

    Prior to the invention of the telescope many astronomers worked out models of the motion of the Moon to predict the position of the Moon in the sky. These geometrical models implied a certain range of distances of the Moon from Earth. Ptolemy's most quoted model predicted that the Moon was nearly twice as far away at apogee than at perigee. Measurements of the angular size of the Moon were within the capabilities of pretelescopic astronomers. Such measurements could have helped refine the models of the motion of the Moon, but hardly anyone seems to have made any measurements that have come down to us. We use a piece of cardboard with a small hole in it which slides up and down a yardstick to show that it is possible to determine the eccentricity ɛ~0.039+/-0.006 of the Moon's orbit. A typical measurement uncertainty of the Moon's angular size is +/-0.8 arc min. Because the Moon's angular size ranges from 29.4 to 33.5 arc min, carefully taken naked eye data are accurate enough to demonstrate periodic variations of the Moon's angular size.

  3. Development and Testing of a Laser-Powered Cryobot for Outer Planet Icy Moon Exploration

    NASA Astrophysics Data System (ADS)

    Siegel, V.; Stone, W.; Hogan, B.; Lelievre, S.; Flesher, C.

    2013-12-01

    Project VALKYRIE (Very-deep Autonomous Laser-powered Kilowatt-class Yo-yoing Robotic Ice Explorer) is a NASA-funded effort to develop the first laser powered cryobot - a self-contained intelligent ice penetrator capable of delivering science payloads through ice caps of the outer planet icy moons. The long range objective is to enable a full-scale Europa lander mission in which an autonomous life-searching underwater vehicle is transported by the cryobot and launched into the sub-surface Europan ocean. Mission readiness testing will involve an Antarctic sub-glacial lake cryobot sample return through kilometers of ice cap thickness. A key element of VALKYRIE's design is the use of a high energy laser as the primary power source. 1070 nm laser light is transmitted at a power level of 5 kW from a surface-based laser and injected into a custom-designed optical waveguide that is spooled out from the descending cryobot. Light exits the downstream end of the fiber, travels through diverging optics, and strikes a beam dump, which channels thermal power to hot water jets that melt the descent hole. Some beam energy is converted, via photovoltaic cells, to electricity for running onboard electronics and jet pumps. Since the vehicle can be sterilized prior to deployment and the melt path freezes behind it, preventing forward contamination, expansions on VALKYRIE concepts may enable cleaner and faster access to sub-glacial Antarctic lakes. Testing at Stone Aerospace between 2010 and 2013 has already demonstrated high power optical energy transfer over relevant (kilometer scale) distances as well as the feasibility of a vehicle-deployed optical waveguide (through which the power is transferred). The test vehicle is equipped with a forward-looking synthetic aperture radar (SAR) that can detect obstacles out to 1 kilometer from the vehicle. The initial ASTEP test vehicle will carry a science payload consisting of a DUV flow cytometer and a water sampling sub-system that will be

  4. Exploring Jupiter's icy moons with old techniques and big facilities - new insights on sulfuric acid hydrates

    NASA Astrophysics Data System (ADS)

    Maynard-Casely, H. E.; Avdeev, M.; Brand, H.; Wallwork, K.

    2013-12-01

    Sulfuric acid hydrates have been proposed to be abundant on the surface of Europa [1], and hence would be important planetary forming materials for this moon and its companions Ganymede and Callisto. Understanding of the surface features and subsurface of these moons could be advanced by firmer knowledge of the icy materials that comprise them [2], insight into which can be drawn from firmer knowledge of physical properties and phase behaviour of the candidate materials. We wish to present results from a study that started with the question ';What form of sulfuric acid hydrate would form on the surface of Europa'. The intrinsic hydrogen-domination of planetary ices, makes studying these materials with laboratory powder diffraction very challenging. Insights into their crystalline phase behavior and the extraction of a number of thermal and mechanical properties is often only accessible with high-flux synchrotron x-ray diffraction and utilization of the large scattering cross section with neutron diffraction. We have used the Powder Diffraction beamline at Australian synchrotron [4] and the Echidna (High-resolution neutron powder diffraction) instrument of the Australian Nuclear Science and Technology Organization, [5] to obtain an number of new insights into the crystalline phases formed from sulfruic acid and water mixtures. These instruments have enabled the discovery a new water-rich sulfuric acid hydrate form [6], improved structural characterisation of existing forms [7] and a charting the phase diagram of this fundamental binary system [8]. This has revealed exciting potential for understanding more about the surface of Europa from space, perhaps even providing a window into its past. [1] Carlson, R.W., R.E. Johnson, and M.S. Anderson, Science, 1999. 286(5437): p. 97-99. [2] Fortes, A.D. and M. Choukroun. Space Sci Rev, 2010. 153(1-4): p. 185-218. [3] Blake, D., et al., Space Sci Rev,, 2012. 170(1-4): p. 341-399. [4] Wallwork, K.S., Kennedy B. J. and Wang, D

  5. Introducing the Moon's Orbital Eccentricity

    ERIC Educational Resources Information Center

    Oostra, Benjamin

    2014-01-01

    I present a novel way to introduce the lunar orbital eccentricity in introductory astronomy courses. The Moon is perhaps the clearest illustration of the general orbital elements such as inclination, ascending node, eccentricity, perigee, and so on. Furthermore, I like the students to discover astronomical phenomena for themselves, by means of a…

  6. Stable Satellite Orbits for Global Coverage of the Moon

    NASA Technical Reports Server (NTRS)

    Ely, Todd; Lieb, Erica

    2006-01-01

    A document proposes a constellation of spacecraft to be placed in orbit around the Moon to provide navigation and communication services with global coverage required for exploration of the Moon. There would be six spacecraft in inclined elliptical orbits: three in each of two orthogonal orbital planes, suggestive of a linked-chain configuration. The orbits have been chosen to (1) provide 99.999-percent global coverage for ten years and (2) to be stable under perturbation by Earth gravitation and solar-radiation pressure, so that no deterministic firing of thrusters would be needed to maintain the orbits. However, a minor amount of orbit control might be needed to correct for such unmodeled effects as outgassing of the spacecraft.

  7. Planetary Protection for the JUpiter ICy moons Explorer (JUICE) Mission Candidate

    NASA Astrophysics Data System (ADS)

    Erd, Christian

    2012-07-01

    The JUICE mission is being studied by ESA in the framework of its Cosmic Vision programme, addressing the topical questions ``What are the conditions for planet formation and emergence of life?'' and ``How does the Solar System work?''. Jupiter can be seen as a paradigm of planetary systems forming a mini-solar system on its own. By investigating its diverse satellites, the understanding of the formation and evolution such of systems would be advanced. The question of whether possible habitats of life are provided underneath the surfaces of the icy satellites Callisto, Ganymede and Europa would be addressed by remote sensing and in situ observations of their surfaces, their compositions and their interiors, including the characterizations of subsurface liquid water oceans, including targeting of recently active regions on Europa for inferring the minimal thickness of the icy crust. JUICE would furthermore provide observations of Jupiter's atmosphere addressing open questions on the circulation at mid-latitudes, and also including coverage of the polar region from a distance of about 29~R_J (see also L. Fletcher et al. in meeting C3.1 "Planetary Atmospheres"). JUICE would study the properties of the magnetosphere and would provide extensive monitoring of Jupiter's plasma environment at distances ranging from more than 100 to 8.5~R_J, which is the distance of Europa. The unique magnetic and plasma interactions between the Jupiter environment and Ganymede would be target to focused investigations, from orbit around Ganymede (see also A. Coates et al in session C3.2 ``Planetary Upper Atmospheres, Ionospheres and Magnetospheres''). The magnetic field and its potential habitability of Ganymede makes it a unique target for specific investigation. The presentation will briefly describe the science objectives of the JUICE mission (see also C.~Erd et al. in session B0.3 ``Active Natural Satellites in the Solar System''), and will then discuss the baseline mission profile

  8. Orbital and Rotational Dynamics of Pluto's Small Moons

    NASA Astrophysics Data System (ADS)

    Showalter, Mark R.; Weaver, Harold A.; Spencer, John R.; Porter, Simon; Hamilton, Douglas P.; Binzel, Richard P.; Buie, Marc W.; Grundy, William M.; Nimmo, Francis; Jacobson, Robert A.; Brozovic, Marina; Throop, Henry B.; Stern, S. A.; Olkin, Catherine B.; Young, Leslie; Ennico, Kimberly; The New Horizons Science Team

    2016-05-01

    Four small moons, Styx, Nix, Kerberos and Hydra, orbit the central binary planet comprising Pluto and Charon. Showalter and Hamilton (Nature 522, 45-49, 2015) analyzed Hubble Space Telescope (HST) data from 2010-2012 to explore some of the dynamical consequences of orbiting a binary planet. They noted evidence for a chaotic rotation of Nix and Hydra, and identified a possible three-body resonance between Styx, Nix and Hydra. We revisit the dynamics of the outer moons based on the data from the New Horizons flyby of July 2015, combined with three more years of HST data. As New Horizons was approaching Pluto, the LORRI camera regularly imaged the moons over a period of approximately 100 days. It also resolved the moons in closeup images, revealing details about the moons' sizes, shapes and surface properties. The LORRI data set has made it possible to derive light curves, rotation rates and pole orientations unambiguously. The moons rotate much faster than they orbit and have high obliquities, suggesting that tidal de-spinning has not played the dominant role in their rotational evolution; impacts may also have played an important role. We will discuss the latest conclusions from a joint analysis of the LORRI and HST data sets, combined with new dynamical simulations. This work was supported by NASA's New Horizons project and by Space Telescope Science Institute.

  9. Orbital and Rotational Dynamics of Pluto's Small Moons

    NASA Astrophysics Data System (ADS)

    Showalter, Mark; Weaver, Harold; Spencer, John; Porter, Simon; Hamilton, Douglas; Binzel, Richard; Buie, Marc; Grundy, William; Nimmo, Francis; Jacobson, Robert; Brozovic, Marina; Stern, S. Alan; Olkin, Cathy; Young, Leslie; Ennico, Kimberly

    2016-04-01

    Four small moons, Styx, Nix, Kerberos and Hydra, orbit the central binary planet comprising Pluto and Charon. Showalter and Hamilton (Nature 522, 45-49, 2015) analyzed Hubble Space Telescope (HST) data from 2010-2012 to explore some of the dynamical consequences of orbiting a binary planet. They noted evidence for a chaotic rotation of Nix and Hydra, and identified a possible three-body resonance between Styx, Nix and Hydra. We revisit the dynamics of the outer moons based on the data from the New Horizons flyby of July 2015, combined with three more years of HST data. As New Horizons was approaching Pluto, the LORRI camera regularly imaged the moons over a period of ~100 days. It also resolved the moons in closeup images, revealing details about the moons' sizes, shapes and surface properties. The LORRI data set has made it possible to derive light curves, rotation rates and pole orientations unambiguously. The moons rotate much faster than they orbit and have high obliquities, suggesting that tidal de-spinning has not played a dominant role in their rotational evolution. We will discuss the latest conclusions from a joint analysis of the LORRI and HST data sets, combined with new dynamical simulations. This work was supported by NASA's New Horizons project and by Space Telescope Science Institute.

  10. Spin-orbital evolution, geophysics and selenodesy of the Moon

    NASA Astrophysics Data System (ADS)

    Gusev, A.; Petrova, N.

    All modern discoveries require taking a new view of the evolution of the Moon, its origin and thermal history: 1. All data and also the modern theories of heat evolution of our satellite give evidences that the Moon has a little (no more 400-500 km) core. 2. The models of formation of the lunar core are consistent with a variety of scenarios. For pure compositions (Fe or FeS, small or large core radii) an entirely solid core is likely, the mean composition of the core is close to the eutectic composition (20 - 25% S). 3. Great importance for core's parameters refinement is the determination of physical librations parameters - librations angles, dissipative Love number k2 and qualitative parameter Q - in various experiments. 4. Present research predict possible values of the periods of new modes for the different models of a lunar core (two-layer or three-layer model, dissipation model) and with various set of parameters: core's radius, thickness of fluid outer core, density for a core's different states of aggregation. 5. The models of convection's evolution of the Moon, calculated by Konrad, Spohn, 1997; Spohn et al., 2001, predict the appearance of several plumes of various intensity and location. Convection model of mascon's formation should be considered (Petrova, Gusev, 2001). The Russian scientific project "The Moon - 2012+" is directed on the solution of fundamental problems of celestial mechanics, selenodesy and geophysics of the Moon - that is connected with pursuance of theoretical researches and computer's modeling: 1. Spin-orbital longtime evolution and physical librations of the multilayered Moon: a) development of the analytical theory of rotation of the two / three-layer Moon and construction on its basis of the physical libration's tables for processing accurate observations and for constructing a lunar annual book; b) analysis of the spin - orbital evolution of the early Moon, an estimation of internal energy dissipation, modeling of the long

  11. Modeling the Orbital Sampling Effect of Extrasolar Moons

    NASA Astrophysics Data System (ADS)

    Heller, René; Hippke, Michael; Jackson, Brian

    2016-04-01

    The orbital sampling effect (OSE) appears in phase-folded transit light curves of extrasolar planets with moons. Analytical OSE models have hitherto neglected stellar limb darkening and non-zero transit impact parameters and assumed that the moon is on a circular, co-planar orbit around the planet. Here, we present an analytical OSE model for eccentric moon orbits, which we implement in a numerical simulator with stellar limb darkening that allows for arbitrary transit impact parameters. We also describe and publicly release a fully numerical OSE simulator (PyOSE) that can model arbitrary inclinations of the transiting moon orbit. Both our analytical solution for the OSE and PyOSE can be used to search for exomoons in long-term stellar light curves such as those by Kepler and the upcoming PLATO mission. Our updated OSE model offers an independent method for the verification of possible future exomoon claims via transit timing variations and transit duration variations. Photometrically quiet K and M dwarf stars are particularly promising targets for an exomoon discovery using the OSE.

  12. Determining the Eccentricity of the Moon's Orbit without a Telescope

    NASA Astrophysics Data System (ADS)

    Krisciunas, Kevin

    2010-01-01

    Ancient Greek astronomers knew that Moon's distance from the Earth was not constant. Ptolemy's model of the Moon's motion implied that the Moon ranged in distance from 33 to 64 Earth radii. This implied that its angular size ranged nearly a factor of two. Tycho Brahe's model of the Moon's motion implied a smaller distance range, some ±3 percent at syzygy. However, the ancient and Renaissance astronomers are notably silent on the subject of measuring the angular size of the Moon as a check on the implied range of distance from their models of the position of the Moon. Using a quarter-inch hole in a piece of cardboard that slides along a yardstick, we show that pre-telescopic astronomers could have measured an accurate mean value of the angular size of the Moon, and that they could have determined a reasonably accurate value of the eccentricity of the Moon's orbit. The principal calibration for each observer is to measure the apparent angular diameter of a 91 mm disk viewed at a distance of 10 meters, giving a true angular size of 31.3 arcmin (the Moon's mean angular size). Because the sighting hole is not much bigger than the size of one's pupil, each observer obtains a personal correction factor with which to scale the raw measures. If one takes data over the course of 7 lunations (7.5 anomalistic months), any systematic errors which are a function of phase should even out over the course of the observations. We find that the random error of an individual observation of ±0.8 arcmin can be achieved.

  13. Decimeter-Wavelength Polarimetric Radar Imaging of the Icy Moons of Jupiter

    NASA Technical Reports Server (NTRS)

    Rosen, P. A.; Gurrola, E. M.; Madsen, S. N.

    2003-01-01

    Imaging radars with wavelengths in the range of 10 cm to 1 m can deeply penetrate the surface of an icy body, revealing details of the geomorphology, local structure, and electrical properties of the upper layers. Radar studies of icy surfaces on Earth have used the polarization state of backscatter echoes at multiple frequencies to characterize the surface and subsurface properties of glaciers, showing relatively smooth surfaces on the scale of radar wave-lengths, and subsurface scattering from volume scatterers consistent with ice pipes and lenses. These volume scattering effects are evident in enhanced polarization ratios over a limited range of backscatter incidence angles. The Galilean satellites exhibit similarly enhanced polarization ratios and volumetric scattering effects, but the observations are limited in angular resolution, leading to ambiguity in interpreting the scattering mechanisms and their structural implications.

  14. Orbital acrobatics in the Sun-Earth-Moon system

    NASA Technical Reports Server (NTRS)

    Farquhar, Robert W.; Dunham, D. W.; Hsu, S. C.

    1986-01-01

    Unconventional trajectory techniques for space missions in the Sun-Earth-Moon system, including libration-point orbits, gravity-assist maneuvers, and Earth-return trajectories are reviewed. The ISEE-3/ICE flight experience is used to illustrate the utility of libration-point orbits called halo-orbits. Five lunar gravity-assist maneuvers used by the ISEE-3/ICE spacecraft are discussed. The final lunar swingby sent the spacecraft into a heliocentric trajectory that will eventually intercept Comet Giacobini-Zinner. As an example of the Earth-return trajectory concept, a proposed mission that includes flybys of three comets and two asteroids is described.

  15. Two-phase convection in the high-pressure ice layer of the large icy moons: geodynamical implications

    NASA Astrophysics Data System (ADS)

    Kalousova, K.; Sotin, C.; Tobie, G.; Choblet, G.; Grasset, O.

    2015-12-01

    The H2O layers of large icy satellites such as Ganymede, Callisto, or Titan probably include a liquid water ocean sandwiched between the deep high-pressure ice layer and the outer ice I shell [1]. It has been recently suggested that the high-pressure ice layer could be decoupled from the silicate core by a salty liquid water layer [2]. However, it is not clear whether accumulation of liquids at the bottom of the high-pressure layer is possible due to positive buoyancy of water with respect to high-pressure ice. Numerical simulation of this two-phase (i.e. ice and water) problem is challenging, which explains why very few studies have self-consistently handled the presence and transport of liquids within the solid ice [e.g. 3]. While using a simplified description of water production and transport, it was recently showed in [4] that (i) a significant fraction of the high-pressure layer reaches the melting point and (ii) the melt generation and its extraction to the overlying ocean significantly influence the global thermal evolution and interior structure of the large icy moons.Here, we treat the high-pressure ice layer as a compressible mixture of solid ice and liquid water [5]. Several aspects are investigated: (i) the effect of the water formation on the vigor of solid-state convection and its influence on the amount of heat that is transferred from the silicate mantle to the ocean; (ii) the fate of liquids within the upper thermal boundary layer - whether they freeze or reach the ocean; and (iii) the effect of salts and volatile compounds (potentially released from the rocky core) on the melting/freezing processes. Investigation of these aspects will allow us to address the thermo-chemical evolution of the internal ocean which is crucial to evaluate the astrobiological potential of large icy moons. This work has been performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. [1] Hussmann et al. (2007), Treatise of

  16. Development of radiative transfer code for JUICE/SWI mission toward the atmosphere of icy moons of Jupiter

    NASA Astrophysics Data System (ADS)

    Yamada, Takayoshi; Kasai, Yasuko; Yoshida, Naohiro

    2016-07-01

    The Submillimeter Wave Instrument (SWI) is one of the scientific instruments on the JUpiter Icy moon Explorer (JUICE). We plan to observe atmospheric compositions including water vapor and its isotopomers in Galilean moons (Io, Europa, Ganymede, and Callisto). The frequency windows of SWI are 530 to 625 GHz and 1080 to 1275 GHz with 100 kHz spectral resolution. We are developing a radiative transfer code in Japan with line-by-line method for Ganymede atmosphere in THz region (0 - 3 THz). Molecular line parameters (line intensity and partition function) were taken from JPL (Jet Propulsion Laboratory) catalogue. The pencil beam was assumed to calculate a spectrum of H _{2}O and CO in rotational transitions at the THz region. We performed comparisons between our model and ARTS (Atmospheric Radiative Transfer Simulator). The difference were less than 10% and 5% for H _{2}O and CO, respectively, under the condition of the local thermodynamic equilibrium (LTE). Comparison with several models with non-LTE assumption will be presented.

  17. Orbital and Rotational Dynamics of Pluto's Small Moons

    NASA Astrophysics Data System (ADS)

    Showalter, Mark R.; Spencer, John R.; Porter, Simon B.; Hamilton, Douglas P.; Binzel, Richard P.; Stern, S. Alan; Weaver, Harold A.; Olkin, Cathy B.; Young, Leslie A.; Ennico, Kimberly

    2015-11-01

    Four small moons, Styx, Nix, Kerberos and Hydra, orbit the central binary planet comprising Pluto and Charon. Showalter and Hamilton (Nature 522, 45-49, 2015) analyzed Hubble Space Telescope (HST) data from 2010-2012 to explore some of the dynamical consequences of orbiting a binary planet. They noted evidence for a chaotic rotation of Nix and Hydra, and identified a possible three-body resonance between Styx, Nix and Hydra. We revisit the dynamics of the outer moons based on the latest data from the New Horizons flyby. As the spacecraft approached Pluto, the LORRI camera regularly imaged the moons over a period of ~100 days. This data set will make it possible to derive light curves and rotation rates unambiguously, something that has not been possible from the sparsely sampled HST data. It also extends the time baseline of the orbit determinations by several years, providing a more precise test of the proposed orbital resonances. We will discuss the latest measurements and their dynamical implications for the evolution of the Pluto system. This work was supported by NASA's New Horizons project.

  18. Thermophysical Property Variations on Saturn's icy moons: A system-wide perspective.

    NASA Astrophysics Data System (ADS)

    Howett, C. J. A.; Spencer, J. R.; Verbiscer, A.

    2013-09-01

    Thermal inertia variations have been observed on icy satellite surfaces throughout the Saturnian system, causing night and daytime temperature variations across the satellites. The most notable are the two 'Pac-Man' anomalies on Mimas and Tethys: distinct regions of high thermal inertia at low latitudes on the leading hemisphere of both satellites, which results in warmer nighttime and cooler daytime temperatures (by ~15 K) than their surroundings. Only subtle differences in surface color had previously been observed in the same region [1]. It is believed that the bombardment of the surface by high-energy electrons alters the surface of Mimas and Tethys, resulting in these high thermal inertia regions. Subtler differences in thermal inertia across other icy satellite surfaces have also been observed. For example: preliminary investigations show Dione may also display a thermal inertia variation that is similar to, but weaker than, Mimas and Tethys' anomalies. Initial investigations have also reveled that the ejecta from Rhea's bright crater Inktomi (14.1 S and 112.1 W) displays higher thermal inertia than its surroundings.

  19. Life detection strategy for Jovian's icy moons: Lessons from subglacial Lake Vostok exploration

    NASA Astrophysics Data System (ADS)

    Bulat, Sergey; Alekhina, Irina; Marie, Dominique; Petit, Jean-Robert

    2010-05-01

    The objective was to estimate the microbial content of accretion ice originating from the subglacial Lake Vostok buried beneath 4-km thick East Antarctic ice sheet with the ultimate goal to discover microbial life in this extreme icy environment. The DNA study constrained by Ancient DNA research criteria was used as a main approach. The flow cytometry was implemented in cell enumerating. As a result, both approaches showed that the accretion ice contains the very low unevenly distributed biomass indicating that the water body should also be hosting a highly sparse life. Up to now, the only accretion ice featured by mica-clay sediments presence allowed the recovery a pair of bacterial phylotypes. This unexpectedly included the chemolithoautotrophic thermophile Hydrogenophilus thermoluteolus and one more unclassified phylotype both passing numerous contaminant controls. In contrast, the deeper and cleaner accretion ice with no sediments presence and near detection limit gas content gave no reliable signals. Thus, the results obtained testify that the search for life in the Lake Vostok is constrained by a high chance of forward-contamination. The subglacial Lake Vostok seems to represent the only extremely clean giant aquatic system on the Earth providing a unique test area for searching for life on icy worlds. The life detection strategy for (sub)glacial environments elsewhere (e.g., Jovian's Europa) should be based on stringent decontamination procedures in clean-room facilities, establishment of on-site contaminant library, implementation of appropriate methods to reach detection level for signal as low as possible, verification of findings through ecological settings of a given environment and repetition at an independent laboratory within the specialized laboratory network.

  20. Hubble Discovery Image of New Moon Orbiting Saturn

    NASA Technical Reports Server (NTRS)

    1995-01-01

    This four-picture sequence (spanning 30 minutes) shows one of four new moons discovered by the Hubble Space Telescope, in images taken of Saturn on May 22, 1995, when Saturn's rings were tilted edge-on to Earth.

    Identified as S/1995 S3, the moon appears as an elongated white spot near the center of each image. The new moon lies just outside Saturn's outermost 'F' ring and is no bigger than about 15 miles across. The brighter object to the left is the moon Epimetheus, which was discovered during the ring-plane crossing of 1966. Both moons change position from frame to frame because they are orbiting the planet.

    Saturn appears as a bright white disk at far right, and the edge-on rings extend diagonally to the upper left. To the left of the vertical line, each image has been processed to remove residual light from the rings and accentuate any faint satellites orbiting near the rings. The long observing times necessary to detect the faint satellites have resulted in Saturn's bright, overexposed appearance.

    Saturn ring plane crossings happen only once every 15 years, and historically have given astronomers an opportunity to discover new satellites that are normally lost in the glare of the planet's bright ring system.

    The Wide Field/Planetary Camera 2 was developed by the Jet Propulsion Laboratory and managed by the Goddard Spaced Flight Center for NASA's Office of Space Science.

    This image and other images and data received from the Hubble Space Telescope are posted on the World Wide Web on the Space Telescope Science Institute home page at URL http://oposite.stsci.edu/pubinfo/

  1. Solar sail orbits at the Earth-Moon libration points

    NASA Astrophysics Data System (ADS)

    Simo, Jules; McInnes, Colin R.

    2009-12-01

    Solar sail technology offer new capabilities for the analysis and design of space missions. This new concept promises to be useful in overcoming the challenges of moving throughout the solar system. In this paper, novel families of highly non-Keplerian orbits for solar sail spacecraft at linear order are investigated in the Earth-Moon circular restricted three-body problem, where the third body is a solar sail. In particular, periodic orbits near the collinear libration points in the Earth-Moon system will be explored along with their applications. The dynamics are completely different from the Earth-Sun system in that the sun line direction constantly changes in the rotating frame but rotates once per synodic lunar month. Using an approximate, first-order analytical solution to the nonlinear nonautonomous ordinary differential equations, periodic orbits can be constructed that are displaced above the plane of the restricted three-body system. This new family of orbits have the property of ensuring visibility of both the lunar far-side and the equatorial regions of the Earth, and can enable new ways of performing lunar telecommunications.

  2. MOM-E: Moon-Orbiting Mothership Explorer

    NASA Technical Reports Server (NTRS)

    Murphy, Gloria A.

    2010-01-01

    The National Aeronautics and Space Administration proposed that a new class of robotic space missions and spacecrafts be introduced to "ensure that future missions are safe, sustainable and affordable". Indeed, the United States space program aims for a return to manned space missions beyond Earth orbit, and robotic explorers are intended to pave the way. This vision requires that all future missions become less costly, provide a sustainable business plan, and increase in safety. Over the course of several fast feasibility studies that considered the 3 drivers above, the small-scale, consumer-driven Moon-Orbiting Mothership Explorer (MOM-E) mission was born. MOM-E's goals are to enable space exploration by offering a scaled down platform which carries multiple small space explorers to the Moon. Each payload will be dropped at their desired destination, offering a competitive price to customers. MOM-E's current scope of operations is limited to the Moon and will be used as a proof of concept mission. However, MOM-E is specifically designed with the idea that the platform is scalable.

  3. Bacterial Motility As a Biosignature: Tests at Icy Moon Analogue Sites

    NASA Astrophysics Data System (ADS)

    Nadeau, J. L.; Lindensmith, C.; Deming, J. W.; Stocker, R.; Graff, E.; Serabyn, E.; Wallace, J. K.; Liewer, K.; Kuhn, J.

    2014-12-01

    Extraterrestrial life in our Solar System, if present, is almost certain to be microbial. Methods and technologies for unambiguous detection of living or extinct microorganisms are needed for life-detection missions to the Jovian and Saturnian moons, where liquid water is known to exist. Our research focuses specifically on microbial meaningful motion as a biosignature—"waving crowds" at the micron scale. Digital Holographic Microscopy (DHM) is an excellent tool for unambiguous identification of bacterial and protozoal swimming, even in the presence of turbidity, drift, and currents. The design of a holographic instrument with bacteria scale resolution was described in the previous talk. In this presentation, we will illustrate the design challenges for construction of a field instrument for extreme environments and space, and present plans for scientific investigations at analogue sites for the coming season. The challenges of creating a field instrument involve performance trade-offs, the ability to operate at extreme temperatures, and handling large volumes of data. A fully autonomous instrument without external cables or power is also desirable, and this is something that previous holographic instruments have not achieved. The primary issues for space exploration are identification of a laser and drive electronics that are qualified for the expected radiation environments of the moons around gas giant planets. Tests in Earth analogue environments will establish performance parameters as well as answer scientific questions that traditional microscopic techniques cannot. Specifically, we will visit a Greenland field site to determine whether or not microorganisms are motile within the brine-filled interior network of sea ice, and if they can be autonomously tracked using the instrument. Motility within the liquid phase of a frozen matrix has been hypothesized to explain how bacteria contribute to the biogeochemical signatures detected in ice, but observational

  4. A SEARCH FOR ASTEROIDS, MOONS, AND RINGS ORBITING WHITE DWARFS

    SciTech Connect

    Di Stefano, Rosanne; Howell, Steve B.; Kawaler, Steven D.

    2010-03-20

    Do white dwarfs host asteroid systems? Although several lines of argument suggest that white dwarfs may be orbited by large populations of asteroids, transits would provide the most direct evidence. We demonstrate that the Kepler mission has the capability to detect transits of white dwarfs by asteroids. Because white-dwarf asteroid systems, if they exist, are likely to contain many asteroids orbiting in a spatially extended distribution, discoveries of asteroid transits can be made by monitoring only a small number of white dwarfs, compatible with Kepler's primary mission, which is to monitor stars with potentially habitable planets. Possible future missions that survey 10 times as many stars with similar sensitivity and minute-cadence monitoring can establish the characteristics of asteroid systems around white dwarfs, such as the distribution of asteroid sizes and semimajor axes. Transits by planets would be more dramatic, but the probability that they will occur is lower. Ensembles of planetary moons and/or the presence of rings around planets can also produce transits detectable by Kepler. The presence of moons and rings can significantly increase the probability that Kepler will discover planets orbiting white dwarfs, even while monitoring only a small number of them.

  5. A Comprehensive Survey of Earth-Moon Libration Orbits: Stationkeeping Strategies And Intra-Orbit Transfers

    NASA Technical Reports Server (NTRS)

    Folta, David; Vaughn, Frank

    2004-01-01

    Cislunar space is a readily accessible region that may well develop into a prime staging area in the effort to colonize space near the Earth or to colonize the moon. While there have been statements made by various NASA programs regarding placement of resources in orbit about the Earth-Moon Lagrangian locations, there is no survey of the total cost associated with attaining and maintaining these unique orbits in an optimal fashion. Transfer trajectories between these orbits required for assembly, servicing, and positioning of these resources have not been extensively investigated. These orbits are dynamically similar to those used for the Sun-Earth missions, but differences in governing gravitational ratios and perturbation sources result in their having their own unique characteristics.

  6. A Survey Of Earth-Moon Libration Orbits: Stationkeeping Strategies And Intra-Orbit Transfers

    NASA Technical Reports Server (NTRS)

    Folta, David; Vaughn, Frank

    2004-01-01

    Cislunar space is a readily accessible region that may well develop into a prime staging area in the effort to colonize space near Earth or to colonize the Moon. While there have been statements made by various NASA programs regarding placement of resources in orbit about the Earth-Moon Lagrangian locations, there is no survey of the total cost associated with attaining and maintaining these unique orbits in an operational fashion. Transfer trajectories between these orbits required for assembly, servicing, and positioning of these resources have not been extensively investigated. These orbits are dynamically similar to those used for the Sun-Earth missions, but differences in governing gravitational ratios and perturbation sources result in unique characteristics. We implement numerical computations using high fidelity models and linear and nonlinear targeting techniques to compute the various maneuver (Delta)V and temporal costs associated with orbits about each of the Earth-Moon Lagrangian locations (L1, L2, L3, L4, and L5). From a dynamical system standpoint, we speak to the nature of these orbits and their stability. We address the cost of transfers between each pair of Lagrangian locations.

  7. Objectives of a prospective Ukrainian orbiter mission to the moon

    NASA Astrophysics Data System (ADS)

    Shkuratov, Yu. G.; Lytvynenko, L. M.; Shulga, V. M.; Yatskiv, Ya. S.; Vidmachenko, A. P.; Kislyulk, V. S.

    2003-06-01

    Ukraine has launch vehicles that are able to deliver about 300 kg to lunar orbit. A future Ukrainian lunar program may propose a polar orbiter. This orbiter should fill principal information gaps in our knowledge about the Moon after the Clementine and Lunar Prospector missions and future missions like Smart-1, Lunar-A, and Selene. We consider that this can be provided by radar studies of the Moon with supporting optical photopolarimetric observations from lunar polar orbit. These experiments allow one to better understand global structure of the lunar surface at a wide range of scales, from microns to kilometers. We propose three instruments for the prospective lunar orbiter. They are a synthetic aperture imaging radar, ground-penetrating radar, and imaging UV-spectropolarimeter. The main purpose of the synthetic aperture imaging radar experiment is to study with high-resolution (50 m) permanently shadowed sites in the lunar polar regions. These sites are cold traps for volatiles, and have a potential for resource utilization. Possible presence of water ice in the regolith in the sites makes them interesting for long-term manned bases on the Moon. Radar and optical imaging and mapping of other interesting regions could be also planned. Multi-frequency, multi-polarization sounding of the lunar surface with ground-penetrating radar can provide data about internal structure of the lunar surface from meters to several hundred meters deep. The ground-penetrating radar can be used for measuring megaregolith properties, detection of cryptomaria, and studies of internal structure of the largest craters. Modest spatial resolution (50 m) of the imaging UV-spectropolarimeter should provide total coverage (or coverage of a large portion) of the lunar surface in oblique viewing at large phase angles. Polarization degree at large (>90°) phase angles bears information about characteristic size of the regolith particles. Additional experiments could use the synthetic aperture

  8. Project “The Moon 2012+”: Spin-orbital evolution, geophysics and selenodesy of the Moon

    NASA Astrophysics Data System (ADS)

    Gusev, Alexander; Petrova, Natalia

    2008-07-01

    The Russian scientific project "The Moon - 2012+" is directed at solving fundamental problems of celestial mechanics, selenodesy and geophysics of the Moon through the pursuance of theoretical research and computer simulations of the following fields. 1. Spin-orbital longtime evolution and physical librations of the multilayered Moon: (a) development of the analytical theory of rotation of the two- /three-layer Moon and construction of the physical libration's tables for processing accurate observations and for constructing a lunar annual book; and (b) analysis of the spin-orbital evolution of the early Moon, an estimation of internal energy dissipation, and modeling of the long-term mechanism maintaining the free librations of the Moon. 2. Geodynamics of a lunar core: analysis of differentiation of a lunar core, detailed elaboration of plume-tectonics of mantle and a core of the early Moon, evolution of a boundary layer of a core-mantle boundary, reconstruction of the gravitational and viscous-mechanical interactions of a lunar core and mantle, research on resonant dissipation of internal energy, and calculation of free and forced nutations of a lunar core and of free fluctuations of a core-mantle system. 3. Selenodesy of lunar far-side: solution of an inverse problem in lunar gravimetry, construction of a geodynamic model of the lunar crust and of a Moho's boundary, reconstruction of initial mascons on the far-side of the Moon, and creation of accurate topographical and gravitational models of the Moon on the basis of modern observations.

  9. Carbonic Acid as a Reserve of Carbon Dioxide on Icy Moons: The Formation of Carbon Dioxide (CO2) in a Polar Environment

    NASA Astrophysics Data System (ADS)

    Jones, Brant M.; Kaiser, Ralf I.; Strazzulla, Giovanni

    2014-06-01

    Carbon dioxide (CO2) has been detected on the surface of several icy moons of Jupiter and Saturn via observation of the ν3 band with the Near-Infrared Mapping Spectrometer on board the Galileo spacecraft and the Visible-Infrared Mapping Spectrometer on board the Cassini spacecraft. Interestingly, the CO2 band for several of these moons exhibits a blueshift along with a broader profile than that seen in laboratory studies and other astrophysical environments. As such, numerous attempts have been made in order to clarify this abnormal behavior; however, it currently lacks an acceptable physical or chemical explanation. We present a rather surprising result pertaining to the synthesis of carbon dioxide in a polar environment. Here, carbonic acid was synthesized in a water (H2O)-carbon dioxide (CO2) (1:5) ice mixture exposed to ionizing radiation in the form of 5 keV electrons. The irradiated ice mixture was then annealed, producing pure carbonic acid which was then subsequently irradiated, recycling water and carbon dioxide. However, the observed carbon dioxide ν3 band matches almost exactly with that observed on Callisto; subsequent temperature program desorption studies reveal that carbon dioxide synthesized under these conditions remains in solid form until 160 K, i.e., the sublimation temperature of water. Consequently, our results suggest that carbon dioxide on Callisto as well as other icy moons is indeed complexed with water rationalizing the shift in peak frequency, broad profile, and the solid state existence on these relatively warm moons.

  10. Analysis of Cassini UVIS Far Ultraviolet Reflectance Spectra to Constrain the Non-Ice Material in Saturn’s Rings and Icy Moons

    NASA Astrophysics Data System (ADS)

    Bradley, Eric Todd; Colwell, J. E.; Esposito, L. W.; Hendrix, A. R.

    2012-10-01

    The FUV spectra of Saturn’s icy ring particles and moons show the presence of an absorbing constituent that presumably is delivered to the system via micrometeoroid bombardment. Understanding the properties of the non-icy material plays into broader questions regarding the age and evolution of the rings. The FUV spectrum contains a water ice absorption edge at 165 nm. The reflectance shortward of the water ice absorption edge is determined by the composition and abundance of the non-icy material whereas the reflectance longward of the absorption edge is determined by both water ice and non-icy material. We have taken two approaches to constrain the properties of the non-ice component of the rings using FUV spectra taken by the Cassini UVIS. In one approach we compare the ring particle Bond albedo, A0, to spectral models with varying abundances and compositions of non-ice components. We first determine A0, across the water ice absorption edge using the classical Chandrasekhar radiative transfer model for the C Ring and Cassini Division with the scattering function replaced by a self-gravity wake model for the A and B rings. We then compare the retrieved values of A0, to spectral models of intimate mixtures where the free parameters are the fractional abundances of the ice and non-ice constituents, grain size, and grain asymmetry parameter for scattering. In the second approach we compare FUV color ratios (180/155 nm) across Saturn’s rings, as well as to icy moons, in order to investigate relative variations in water ice abundance in these objects. We find that A0, longward of the absorption edge peaks in the outer B ring and reaches a minimum in the C Ring and Cassini Division, consistent with the purest water ice being found in the B Ring and the most polluted in the C Ring and Cassini Division.

  11. Orbit Determination of Spacecraft in Earth-Moon L1 and L2 Libration Point Orbits

    NASA Technical Reports Server (NTRS)

    Woodard, Mark; Cosgrove, Daniel; Morinelli, Patrick; Marchese, Jeff; Owens, Brandon; Folta, David

    2011-01-01

    The ARTEMIS mission, part of the THEMIS extended mission, is the first to fly spacecraft in the Earth-Moon Lissajous regions. In 2009, two of the five THEMIS spacecraft were redeployed from Earth-centered orbits to arrive in Earth-Moon Lissajous orbits in late 2010. Starting in August 2010, the ARTEMIS P1 spacecraft executed numerous stationkeeping maneuvers, initially maintaining a lunar L2 Lissajous orbit before transitioning into a lunar L1 orbit. The ARTEMIS P2 spacecraft entered a L1 Lissajous orbit in October 2010. In April 2011, both ARTEMIS spacecraft will suspend Lissajous stationkeeping and will be maneuvered into lunar orbits. The success of the ARTEMIS mission has allowed the science team to gather unprecedented magnetospheric measurements in the lunar Lissajous regions. In order to effectively perform lunar Lissajous stationkeeping maneuvers, the ARTEMIS operations team has provided orbit determination solutions with typical accuracies on the order of 0.1 km in position and 0.1 cm/s in velocity. The ARTEMIS team utilizes the Goddard Trajectory Determination System (GTDS), using a batch least squares method, to process range and Doppler tracking measurements from the NASA Deep Space Network (DSN), Berkeley Ground Station (BGS), Merritt Island (MILA) station, and United Space Network (USN). The team has also investigated processing of the same tracking data measurements using the Orbit Determination Tool Kit (ODTK) software, which uses an extended Kalman filter and recursive smoother to estimate the orbit. The orbit determination results from each of these methods will be presented and we will discuss the advantages and disadvantages associated with using each method in the lunar Lissajous regions. Orbit determination accuracy is dependent on both the quality and quantity of tracking measurements, fidelity of the orbit force models, and the estimation techniques used. Prior to Lissajous operations, the team determined the appropriate quantity of tracking

  12. Space tourism: from earth orbit to the moon

    NASA Astrophysics Data System (ADS)

    Collins, P.

    Travel to and from the lunar surface has been known to be feasible since it was first achieved 34 years ago. Since that time there has been enormous progress in related engineering fields such as rocket propulsion, materials and avionics, and about 1 billion has been spent on lunar science and engineering research. Consequently there are no fundamental technical problems facing the development of lunar tourism - only business and investment problems. The outstanding problem is to reduce the cost of launch to low Earth orbit. Recently there has been major progress towards overturning the myth that launch costs are high because of physical limits. Several "X Prize" competitor vehicles currently in test-flight are expected to be able to perform sub-orbital flights at approximately 1/1,000 of the cost of Alan Shepard's similar flight in 1961. This activity could have started 30 years ago if space agencies had had economic rather than political objectives. A further encouraging factor is that the demand for space tourism seems potentially limitless. Starting with sub-orbital flights and growing through orbital activities, travel to the Moon will offer further unique attractions. In every human culture there is immense interest in the Moon arising from millennia of myths. In addition, bird-like flying sports, first described by Robert Heinlein, will become another powerful demand factor. Roundtrips of 1 to 2 weeks are very convenient for travel companies; and the radiation environment will permit visitors several days of surface activity without significant health risks. The paper also discusses economic aspects of lunar tourism, including the benefits it will have for those on Earth. Lunar economic development based on tourism will have much in common with economic development on Earth based on tourism: starting from the fact that many people spontaneously wish to visit popular places, companies in the tourism industry invest to sell a growing range of services to ever

  13. The Saturn System's Icy Satellites: New Results from Cassini

    NASA Technical Reports Server (NTRS)

    Lopes-Gautier, Rosaly M.; Buratti, Bonnie; Hendrix, A. R.

    2008-01-01

    Cassini-Huygens is a multidisciplinary, international planetary mission consisting of an orbiting spacecraft and a probe. The Huygens probe successfully landed on Titan's surface on January 14, 2005, while the orbiter has performed observations of Saturn, its rings, satellites, and magnetosphere since it entered orbit around Saturn on July 1, 2004. The Cassini mission has been prolific in its scientific discoveries about the Saturn system. In this special section, we present new mission results with a focus on the 'icy satellites,' which we define as all Saturn's moons with the exception of Titan. The results included in this section have come out of the Cassini SOST--Satellites Orbiter Science Team--a multi-instrument and multidiscipline group that works together to better understand the icy satellites and their interactions with Saturn and its rings. Other papers included in this issue present ground-based observations and interior modeling of these icy moons.

  14. On-orbit spatial characterization of VIIRS using the Moon

    NASA Astrophysics Data System (ADS)

    Wang, Zhipeng (Ben); Xiong, Xiaoxiong (Jack)

    2013-09-01

    The moon is a stable source for the on-orbit calibration of the space-borne sensors with regular lunar observation capability, such as MODIS on-board the Terra and Aqua satellites and VIIRS on-board the Suomi NPP satellite. The spectral bands of both sensors are located on multiple focal plane assemblies and spatially co-registered in both the along-scan and along-track directions. Any mis-registration, or the band-to-band registration (BBR) shift, can deteriorate the quality of the science products that are derived from the data of multiple spectral bands. In this paper, the VIIRS spatial performance, mainly focusing on its BBR, is characterized using its lunar observations via an algorithm developed and verified for MODIS. In this algorithm, the centroids of the lunar images of various bands are calculated and the BBR shift between bands is determined by differentiating these centroids. Results show that the on-orbit change of the BBR has been small for VIIRS reflective solar bands (RSB) since its launch in Oct. 2011. The modulation transfer function (MTF), a measure of the image sharpness of an optical system, is also derived for RSB from the same set of lunar images by an algorithm inherited from MODIS characterization. The VIIRS on-orbit MTF in the along-track direction is trended and shown to have been stable.

  15. Absolute irradiance of the Moon for on-orbit calibration

    USGS Publications Warehouse

    Stone, T.C.; Kieffer, H.H.

    2002-01-01

    The recognized need for on-orbit calibration of remote sensing imaging instruments drives the ROLO project effort to characterize the Moon for use as an absolute radiance source. For over 5 years the ground-based ROLO telescopes have acquired spatially-resolved lunar images in 23 VNIR (Moon diameter ???500 pixels) and 9 SWIR (???250 pixels) passbands at phase angles within ??90 degrees. A numerical model for lunar irradiance has been developed which fits hundreds of ROLO images in each band, corrected for atmospheric extinction and calibrated to absolute radiance, then integrated to irradiance. The band-coupled extinction algorithm uses absorption spectra of several gases and aerosols derived from MODTRAN to fit time-dependent component abundances to nightly observations of standard stars. The absolute radiance scale is based upon independent telescopic measurements of the star Vega. The fitting process yields uncertainties in lunar relative irradiance over small ranges of phase angle and the full range of lunar libration well under 0.5%. A larger source of uncertainty enters in the absolute solar spectral irradiance, especially in the SWIR, where solar models disagree by up to 6%. Results of ROLO model direct comparisons to spacecraft observations demonstrate the ability of the technique to track sensor responsivity drifts to sub-percent precision. Intercomparisons among instruments provide key insights into both calibration issues and the absolute scale for lunar irradiance.

  16. Development of 2-D Array of Superconducting Magnesium Diboride (MgB2) for Far-IR Investigations of the Outer Planets and Icy Moons

    NASA Astrophysics Data System (ADS)

    Lakew, Brook

    2009-09-01

    A 2-D array of superconducting Magnesium Diboride(MgB2) far -IR thermal detectors has been fabricated. Such an array is intended to be at the focal plane of future generation thermal imaging far-IR instruments that will investigate the outer planets and their icy moons. Fabrication and processing of the pixels of the array as well as noise characterization of architectured MgB2 thin films will be presented. Challenges and solutions for improving the performance of the array will be discussed.

  17. Carbonic acid as a reserve of carbon dioxide on icy moons: The formation of carbon dioxide (CO{sub 2}) in a polar environment

    SciTech Connect

    Jones, Brant M.; Kaiser, Ralf I.; Strazzulla, Giovanni

    2014-06-20

    Carbon dioxide (CO{sub 2}) has been detected on the surface of several icy moons of Jupiter and Saturn via observation of the ν{sub 3} band with the Near-Infrared Mapping Spectrometer on board the Galileo spacecraft and the Visible-Infrared Mapping Spectrometer on board the Cassini spacecraft. Interestingly, the CO{sub 2} band for several of these moons exhibits a blueshift along with a broader profile than that seen in laboratory studies and other astrophysical environments. As such, numerous attempts have been made in order to clarify this abnormal behavior; however, it currently lacks an acceptable physical or chemical explanation. We present a rather surprising result pertaining to the synthesis of carbon dioxide in a polar environment. Here, carbonic acid was synthesized in a water (H{sub 2}O)-carbon dioxide (CO{sub 2}) (1:5) ice mixture exposed to ionizing radiation in the form of 5 keV electrons. The irradiated ice mixture was then annealed, producing pure carbonic acid which was then subsequently irradiated, recycling water and carbon dioxide. However, the observed carbon dioxide ν{sub 3} band matches almost exactly with that observed on Callisto; subsequent temperature program desorption studies reveal that carbon dioxide synthesized under these conditions remains in solid form until 160 K, i.e., the sublimation temperature of water. Consequently, our results suggest that carbon dioxide on Callisto as well as other icy moons is indeed complexed with water rationalizing the shift in peak frequency, broad profile, and the solid state existence on these relatively warm moons.

  18. Stationkeeping of the First Earth-Moon Libration Orbiters: The ARTEMIS Mission

    NASA Technical Reports Server (NTRS)

    Folta, David; Woodard, Mark; Cosgrove, D.

    2011-01-01

    Libration point orbits near collinear locations are inherently unstable and must be controlled. For Acceleration Reconnection and Turbulence and Electrodynamics of the Moon's Interaction with the Sun (ARTEMIS) Earth-Moon Lissajous orbit operations, stationkeeping is challenging because of short time scales, large orbital eccentricity of the secondary, and solar gravitational and radiation pressure perturbations. ARTEMIS is the first NASA mission continuously controlled at both Earth-Moon L1 and L2 locations and uses a balance of optimization, spacecraft implementation and constraints, and multi-body dynamics. Stationkeeping results are compared to pre-mission research including mode directions.

  19. Preliminary Design Considerations for Access and Operations in Earth-Moon L1/L2 Orbits

    NASA Technical Reports Server (NTRS)

    Folta, David C.; Pavlak, Thomas A.; Haapala, Amanda F.; Howell, Kathleen C.

    2013-01-01

    Within the context of manned spaceflight activities, Earth-Moon libration point orbits could support lunar surface operations and serve as staging areas for future missions to near-Earth asteroids and Mars. This investigation examines preliminary design considerations including Earth-Moon L1/L2 libration point orbit selection, transfers, and stationkeeping costs associated with maintaining a spacecraft in the vicinity of L1 or L2 for a specified duration. Existing tools in multi-body trajectory design, dynamical systems theory, and orbit maintenance are leveraged in this analysis to explore end-to-end concepts for manned missions to Earth-Moon libration points.

  20. Impact chemistry of methanol: Implications for volatile evolution on icy satellites and dwarf planets, and cometary delivery to the Moon

    NASA Astrophysics Data System (ADS)

    Sekine, Yasuhito; Genda, Hidenori; Muto, Yuta; Sugita, Seiji; Kadono, Toshihiko; Matsui, Takafumi

    2014-11-01

    Methanol (CH3OH) is one of the primordial volatiles contained within icy solids in the outer solar nebula. This paper investigates the impact chemistry of CH3OH ice through a series of impact experiments. We discuss its fate during the accretion and evolution stages of large icy bodies, and assess the possibility of intact delivery of cometary volatiles to the lunar surface. Our experimental results show that the peak shock pressures for initial and complete dissociation of CH3OH ice are approximately 9 and 28 GPa, respectively. We also found that CO is more abundant than CH4 in the gas-phase products of impact-induced CH3OH dissociation. Our results further show that primordial CH3OH within icy planetesimals could have survived low-velocity impacts during accretion of icy satellites and dwarf planets. These results suggest that CH3OH may have been a source of soluble reducing carbon and that it may have acted as antifreeze in liquid interior oceans of large icy bodies. In contrast, CH3OH acquired by accretion on icy satellites and Ceres would have been dissociated efficiently by subsequent impacts, perhaps during the heavy bombardment period, owing to the expected high impact velocities. For example, if Callisto originally contained CH3OH, cometary impacts during the late heavy bombardment period would have resulted in the formation of a substantial atmosphere (ca. ⩾10-4 bar) composed of CO, H2, and CH4. To account for the current CO levels in Titan's atmosphere, the CH3OH content in its crust may have been much lower than that typical of comets. Our numerical simulations also indicate that intact delivery of cometary CH3OH to the lunar surface would not have occurred, which suggests that CH3OH found in a persistently-shadowed lunar region probably formed through low-temperature surface chemistry on regolith.

  1. Measuring the Orbital Period of the Moon Using a Digital Camera

    ERIC Educational Resources Information Center

    Hughes, Stephen W.

    2006-01-01

    A method of measuring the orbital velocity of the Moon around the Earth using a digital camera is described. Separate images of the Moon and stars taken 24 hours apart were loaded into Microsoft PowerPoint and the centre of the Moon marked on each image. Four stars common to both images were connected together to form a "home-made" constellation.…

  2. Earth and Moon encounters by the Galileo Jupiter orbiter

    NASA Technical Reports Server (NTRS)

    Clarke, T. C.

    1988-01-01

    The Galileo Venus-Earth-Earth-Gravity-Assist trajectory to Jupiter is discussed. It includes two encounters from deep space with the Earth and the Earth-Moon system. Fortuitous and unique opportunities therefore exist to observe and study the Earth and Earth's moon during both of these encounters. Given the Galileo science payload, a candidate set of Earth and Moon science objectives is presented. The conditions and constraints of the Earth and Moon encounters, which define the observing opportunity, and which bound the objectives, are reviewed.

  3. Monitoring of the Moon: unstable motion and regular orbits of lunar artificial satellites

    NASA Astrophysics Data System (ADS)

    Perov, N. I.; Kondratieva, A. V.

    2012-09-01

    In the model of the 4-body problem: the Moon and 3 artificial station - the stable trajectories for the chaotic motion and unstable orbits for the regular motion of the point with negligible mass are found.

  4. Report of the Terrestrial Bodies Science Working Group. Volume 4: The moon. [lunar polar orbiter mission

    NASA Technical Reports Server (NTRS)

    Haskin, L. A.; Duke, M. B.; Hubbard, N.; Johnson, T. V.; Malin, M. C.; Minear, J.

    1977-01-01

    A rationale for furture exploration of the moon is given. Topics discussed include the objectives of the lunar polar orbiter mission, the mission profile, and general characteristics of the spacraft to be used.

  5. The modal solution to the Moon's orbit using canonical Floquet perturbation theory

    NASA Astrophysics Data System (ADS)

    Vogel, Kurt A.

    1993-12-01

    Using the restricted three body problem, the equations of motion (EOM) and Hamiltonian are computed for the moon's orbit in physical variables. A periodic orbit is found in the vicinity of the moon's orbit, and classical Floquet theory is applied to the periodic orbit to give stability information and the complete solution to the equations of variation. Floquet theory also supplies a transformation from physical variables to modal variables. This transformation to modal variables is made canonical by constraining the initial transformation matrix to be symplectic. Actual lunar data is used to calculate the modes for the real moon's orbit. Once satisfied that the moon's real-world modes are in (or near) the linear regime of the periodic orbit, the modal EOM are found by doing a perturbation expansion on the new modal Hamiltonian. The modal results from the real lunar orbit are compared with the modal EOM/expansion results. The modal expansion proves to be an accurate solution to the moon's orbit given enough expansion terms.

  6. Evaluation of infrared emission spectroscopy for mapping the Moon's surface composition from lunar orbit

    NASA Technical Reports Server (NTRS)

    Nash, Douglas B.; Salisbury, John W.; Conel, James E.; Lucey, Paul G.; Christensen, Philip R.

    1993-01-01

    Infrared thermal emission spectroscopy is evaluated for its possible application to compositional mapping of the Moon's surface from lunar orbit. Principles of the mid-IR (approximately 4-25 microns) technique, previous lunar ground-based observations, and laboratory studies of Moon samples are reviewed and summarized. A lunar thermal emission spectrometer experiment is described, patterned after a similar instrument on the Mars Observer spacecraft. Thermal emission spectrometry from a polar-orbiting lunar spacecraft could provide a valuable mapping tool to aid in exploration for lunar resources and help provide understanding of the origin of the Moon and history of lunar surface processes.

  7. A numerical investigation of planetesimal collision trajectories with a Moon accumulating in Earth orbit

    NASA Technical Reports Server (NTRS)

    Cox, L. P.

    1984-01-01

    In the scenario of lunar origin in which the Moon is assumed to have accreted most of its mass while in orbit about the Earth, ismals on the accrea knowledge of the relative impact rates of heliocentric planetting Earth and Moon is essential for any attempt to establish dynamical constraints on lunar origin. Numerical integrations of the regularized equations of motion for four bodies (Sun, Earth, Moon, planetismal) were done. A planetismal impact trajectory was calculated by assuming that the planetismal has hit the surface of the Moon at an assumed location, traveling in an assumed direction, and with an assumed impact speed. Next, the equations of motion were numerically integrated backward in time in order to determine from where the planetismal has come. In this way those volumes in heliocentric orbital element space which contribute trajectories that directly impact the Moon.

  8. Moon formation and orbital evolution in extrasolar planetary systems - A literature review

    NASA Astrophysics Data System (ADS)

    Lewis, K.

    2011-02-01

    With over 450 extrasolar planets detected, the possibility of searching for moons of these planets is starting to be investigated. In order to make efficient use of limited observing resources, it would be useful if the types of moons that a given planet is likely to host was known prior to detection. Fortunately, informed by simulations of moon formation in our own solar system, as well as more general theoretical investigations of moon orbital evolution, such information is now available. I present a review of literature results concerning the likely physical and orbital properties of extra-solar moons, and how these properties are predicted to vary with the properties of their host planet.

  9. Large impacts and tectonism: the relative ages of the basin Odysseus and Ithaca Chasma on Saturn's icy moon Tethys

    NASA Astrophysics Data System (ADS)

    Wagner, Roland; Stephan, Katrin; Schmedemann, Nico; Roatsch, Thomas; Kersten, Elke; Neukum, Gerhard; Denk, Tilmann; Porco, Carolyn C.

    2014-05-01

    Large impact events forming craters of basin size (> 200 - 300 km in diameter) on planets, asteroids or planetary satellites can cause intense tectonic deformation on their surfaces, indicated by concentric and/or radial troughs or ridges [e.g., 1]. Recently, sets of parallel grooves on asteroid (4) Vesta have been discussed to be the result of impact-related deformation in connection with basin-forming events on Vesta's south polar area [2]. On Saturn's mid-sized icy satellites Tethys, 1072 km in diameter, major landforms are the 445 km large impact basin Odysseus and the huge graben system of Ithaca Chasma which were first imaged during the Voyager encounters in 1980 and 1981 [3][4]. Ithaca Chasma is a ~100 km wide terraced trough. It has been discussed that Ithaca Chasma could be the result of structural deformation caused by the impact event that created Odysseus [4][5]. Preliminary mapping and crater counts using Cassini ISS imaging data on Odysseus and Ithaca Chasma, however, infer that this has not been the case [6]. Cassini VIMS spectral data show that Ithaca Chasma has less ice compared to Odysseus which supports this finding that it is older than the basin [7]. Major problems to exactly define the stratigraphic position of Ithaca Chasma with respect to the basin Odysseus are (1) that only those craters are allowed to be used for crater counts which clearly superimpose the tectonic structures (e.g., the terraced scarps) across the chasm, and (2) further geologic processes that affected the chasm interior caused obliteration of craters which results in lower crater frequencies. Our preliminary crater counts [6] were carried out on lower-resolution Cassini imaging data. During Cassini's orbital tour since July 2004, the ISS cameras have provided almost complete global image coverage of Tethys at resolutions of 100 - 300 m/pxl. In this work we present results from our ongoing studies on Tethys' geology, based on these new imaging data, primarily focused on

  10. Circumlunar Free-Return Cycler Orbits for a Manned Earth-Moon Space Station

    NASA Technical Reports Server (NTRS)

    Genova, Anthony L.; Aldrin, Buzz

    2015-01-01

    Multiple free-return circumlunar cycler orbits were designed to allow regular travel between the Earth and Moon by a manned space station. The presented cycler orbits contain circumlunar free-return "figure-8" segments and yield lunar encounters every month. Smaller space "taxi" vehicles can rendezvous with (and depart from) the cycling Earth-Moon space station to enter lunar orbit (and/or land on the lunar surface), return to Earth, or reach destinations including Earth-Moon L1 and L2 halo orbits, near-Earth objects (NEOs), Venus, and Mars. To assess the practicality of the selected orbits, relevant cycler characteristics (including (Delta)V maintenance requirements) are presented and compared.

  11. Applications of High Etendue Line-Profile Spectro-Polarimetry to the Study of the Atmospheric and Magnetospheric Environments of the Jovian Icy Moons

    NASA Technical Reports Server (NTRS)

    Harris, Walter M.; Roesler, Fred L.; Jaffel, Lotfi Ben; Ballester, Gilda E.; Oliversen, Ronald J.; Morgenthaler, Jeffrey P.; Mierkiewicz, Edwin

    2003-01-01

    Electrodynamic effects play a significant, global role in the state and energization of the Earth's ionosphere/magnetosphere, but even more so on Jupiter, where the auroral energy input is four orders of magnitude greater than on Earth. The Jovian magnetosphere is distinguished from Earth's by its rapid rotation rate and contributions from satellite atmospheres and internal plasma sources. The electrodynamic effects of these factors have a key role in the state and energization of the ionosphere-corona- plasmasphere system of the planet and its interaction with Io and the icy satellites. Several large scale interacting processes determine conditions near the icy moons beginning with their tenuous atmospheres produced from sputtering, evaporative, and tectonic/volcanic sources, extending out to exospheres that merge with ions and neutrals in the Jovian magnetosphere. This dynamic environment is dependent on a complex network of magnetospheric currents that act on global scales. Field aligned currents connect the satellites and the middle and tail magnetospheric regions to the Jupiter's poles via flux tubes that produce as bright auroral and satellite footprint emissions in the upper atmosphere. This large scale transfer of mass, momentum, and energy (e.g. waves, currents) means that a combination of complementary diagnostics of the plasma, neutral, and and field network must be obtained near simultaneously to correctly interpret the results. This presentation discusses the applicability of UV spatial heterodyne spectroscopy (SHS) to the broad study of this system on scales from satellite surfaces to Jupiter's aurora and corona.

  12. Automated Estimation of the Orbital Parameters of Jupiter's Moons

    NASA Astrophysics Data System (ADS)

    Western, Emma; Ruch, Gerald T.

    2016-01-01

    Every semester the Physics Department at the University of St. Thomas has the Physics 104 class complete a Jupiter lab. This involves taking around twenty images of Jupiter and its moons with the telescope at the University of St. Thomas Observatory over the course of a few nights. The students then take each image and find the distance from each moon to Jupiter and plot the distances versus the elapsed time for the corresponding image. Students use the plot to fit four sinusoidal curves of the moons of Jupiter. I created a script that automates this process for the professor. It takes the list of images and creates a region file used by the students to measure the distance from the moons to Jupiter, a png image that is the graph of all the data points and the fitted curves of the four moons, and a csv file that contains the list of images, the date and time each image was taken, the elapsed time since the first image, and the distances to Jupiter for Io, Europa, Ganymede, and Callisto. This is important because it lets the professor spend more time working with the students and answering questions as opposed to spending time fitting the curves of the moons on the graph, which can be time consuming.

  13. Lunar Dynamics on Internal Structure of the Moon on the orbit around the planet Earth

    NASA Astrophysics Data System (ADS)

    Nakamura, Shigehisa

    2015-04-01

    This work concerns on problem of dynamics of the Moon rotating on the orbit around the Earth. First, the author introduces what about on the reference data which was updated by NASA in 2013. The NASA's mission of GRAIL (Gravity Recovery and Interior Laboratory)in 2012 was a key to obtain the lunar gravity field on the whole area of the Moon's surface. Now, the author introduces his dynamical model for obtaining an advanced understanding of the lunar internal structure inside of the Moon's surface. The data obtained by NASA had shown that the crust on the moon near side to the Earth was about 30 km thick and that on the moon far side to the Earth was was 50 km. Then, a bold modelling can be introduced for the existing Moon's internal structure referring to the fruuits of the research works in the field of the Earth's gravity found on the basis of the past contributions in the field of geodesy under several bold assumptions wich have been accepted in the fields of astronomy and of the space sciences. In brief, the Moon's gravity could reduce the lunar interface of the core must be surely excentric boldly about 10 km inside of the orbit on the radial line between the Moon and the Earth.Hence, the lunar magnetic field must be freezed to show the reversed polarity relative to that of the Earth. Neverthless, it should be updated to the details in the successive research.

  14. Measuring the orbital period of the Moon using a digital camera

    NASA Astrophysics Data System (ADS)

    Hughes, Stephen W.

    2006-03-01

    A method of measuring the orbital velocity of the Moon around the Earth using a digital camera is described. Separate images of the Moon and stars taken 24 hours apart were loaded into Microsoft PowerPoint and the centre of the Moon marked on each image. Four stars common to both images were connected together to form a 'home-made' constellation. On each image the Moon and constellation were grouped together. The group from one image was pasted onto the other image and translated and rotated so that the two constellations overlay each other. The distance between the Moon centres in pixels was converted into a physical distance on the CCD chip in order to calculate the angular separation on the sky. The angular movement was then used to calculate the orbital period of the Moon. A metre rule was photographed from a known distance in order to calculate the physical size of the CCD pixels. The orbital period of the Moon was measured as 27.1 days, which is within 0.7% of the actual period of 27.3 days.

  15. NEXT GENERATION OF TELESCOPES OR DYNAMICS REQUIRED TO DETERMINE IF EXO-MOONS HAVE PROGRADE OR RETROGRADE ORBITS

    SciTech Connect

    Lewis, Karen M.; Fujii, Yuka

    2014-08-20

    We survey the methods proposed in the literature for detecting moons of extrasolar planets in terms of their ability to distinguish between prograde and retrograde moon orbits, an important tracer of the moon formation channel. We find that most moon detection methods, in particular, sensitive methods for detecting moons of transiting planets, cannot observationally distinguishing prograde and retrograde moon orbits. The prograde and retrograde cases can only be distinguished where the dynamical evolution of the orbit due to, e.g., three body effects is detectable, where one of the two cases is dynamically unstable, or where new observational facilities, which can implement a technique capable of differentiating the two cases, come online. In particular, directly imaged planets are promising targets because repeated spectral and photometric measurements, which are required to determine moon orbit direction, could also be conducted with the primary interest of characterizing the planet itself.

  16. The Solar-Radiation Pressure Effects on the Orbital Evolution of Asteroid Moons

    NASA Astrophysics Data System (ADS)

    Troianskyi, V. V.; Bazyey, O. A.

    In the theory of motion, disturbances are divided into gravitational and non-gravitational ones. In this paper, we discuss the effects of solar-radiation pressure on the orbital evolution of asteroid moons. It is known from the laws of physics that the smaller an object is the more pressure is exerted on it by solar radiation. That is the reason why asteroid moons with their small sizes are exposed to the solar-radiation pressure so much.

  17. Dynamics of Orbits near 3:1 Resonance in the Earth-Moon System

    NASA Technical Reports Server (NTRS)

    Dichmann, Donald J.; Lebois, Ryan; Carrico, John P., Jr.

    2013-01-01

    The Interstellar Boundary Explorer (IBEX) spacecraft is currently in a highly elliptical orbit around Earth with a period near 3:1 resonance with the Moon. Its orbit is oriented so that apogee does not approach the Moon. Simulations show this orbit to be remarkably stable over the next twenty years. This article examines the dynamics of such orbits in the Circular Restricted 3-Body Problem (CR3BP). We look at three types of periodic orbits, each exhibiting a type of symmetry of the CR3BP. For each of the orbit types, we assess the local stability using Floquet analysis. Although not all of the periodic solutions are stable in the mathematical sense, any divergence is so slow as to produce practical stability over several decades. We use Poincare maps with twenty-year propagations to assess the nonlinear stability of the orbits, where the perturbation magnitudes are related to the orbit uncertainty for the IBEX mission. Finally we show that these orbits belong to a family of orbits connected in a bifurcation diagram that exhibits exchange of stability. The analysis of these families of period orbits provides a valuable starting point for a mission orbit trade study.

  18. A Free-Return Earth-Moon Cycler Orbit for an Interplanetary Cruise Ship

    NASA Technical Reports Server (NTRS)

    Genova, Anthony L.; Aldrin, Buzz

    2015-01-01

    A periodic circumlunar orbit is presented that can be used by an interplanetary cruise ship for regular travel between Earth and the Moon. This Earth-Moon cycler orbit was revealed by introducing solar gravity and modest phasing maneuvers (average of 39 m/s per month) which yields close-Earth encounters every 7 or 10 days. Lunar encounters occur every 26 days and offer the chance for a smaller craft to depart the cycler and enter lunar orbit, or head for a Lagrange point (e.g., EM-L2 halo orbit), distant retrograde orbit (DRO), or interplanetary destination such as a near-Earth object (NEO) or Mars. Additionally, return-to-Earth abort options are available from many points along the cycling trajectory.

  19. PHYSICAL CHARACTERISTICS AND NON-KEPLERIAN ORBITAL MOTION OF 'PROPELLER' MOONS EMBEDDED IN SATURN'S RINGS

    SciTech Connect

    Tiscareno, Matthew S.; Burns, Joseph A.; Hedman, Matthew M.; Milano, Anthony J.; Evans, Michael W.; Sremcevic, Miodrag; Beurle, Kevin; Cooper, Nicholas J.; Porco, Carolyn C.; Spitale, Joseph N.; Weiss, John W.

    2010-08-01

    We report the discovery of several large 'propeller' moons in the outer part of Saturn's A ring, objects large enough to be followed over the 5 year duration of the Cassini mission. These are the first objects ever discovered that can be tracked as individual moons, but do not orbit in empty space. We infer sizes up to 1-2 km for the unseen moonlets at the center of the propeller-shaped structures, though many structural and photometric properties of propeller structures remain unclear. Finally, we demonstrate that some propellers undergo sustained non-Keplerian orbit motion.

  20. Extension of Earth-Moon libration point orbits with solar sail propulsion

    NASA Astrophysics Data System (ADS)

    Heiligers, Jeannette; Macdonald, Malcolm; Parker, Jeffrey S.

    2016-07-01

    This paper presents families of libration point orbits in the Earth-Moon system that originate from complementing the classical circular restricted three-body problem with a solar sail. Through the use of a differential correction scheme in combination with a continuation on the solar sail induced acceleration, families of Lyapunov, halo, vertical Lyapunov, Earth-centred, and distant retrograde orbits are created. As the solar sail circular restricted three-body problem is non-autonomous, a constraint defined within the differential correction scheme ensures that all orbits are periodic with the Sun's motion around the Earth-Moon system. The continuation method then starts from a classical libration point orbit with a suitable period and increases the solar sail acceleration magnitude to obtain families of orbits that are parametrised by this acceleration. Furthermore, different solar sail steering laws are considered (both in-plane and out-of-plane, and either fixed in the synodic frame or fixed with respect to the direction of Sunlight), adding to the wealth of families of solar sail enabled libration point orbits presented. Finally, the linear stability properties of the generated orbits are investigated to assess the need for active orbital control. It is shown that the solar sail induced acceleration can have a positive effect on the stability of some orbit families, especially those at the L2 point, but that it most often (further) destabilises the orbit. Active control will therefore be needed to ensure long-term survivability of these orbits.

  1. DESTINATION MOON: A history of the Lunar Orbiter Program

    NASA Technical Reports Server (NTRS)

    Byers, B. A.

    1977-01-01

    The origins of the Lunar Orbiter Program and the activities of the missions then in progress are documented. The period 1963 - 1970 when lunar orbiters were providing the Apollo program with photographic and selenodetic data for evaluating proposed astronaut landing sites is covered.

  2. RADIATION SYNTHESIS OF CARBON DIOXIDE IN ICE-COATED CARBON: IMPLICATIONS FOR INTERSTELLAR GRAINS AND ICY MOONS

    SciTech Connect

    Raut, U.; Fulvio, D.; Baragiola, R. A.; Loeffler, M. J.

    2012-06-20

    We report the synthesis of carbon dioxide on an amorphous carbon-13 substrate coated with amorphous water ice from irradiation with 100 keV protons at 20 K and 120 K. The quantitative studies show that the CO{sub 2} is dispersed in the ice; its column density increases with ion fluence to a maximum value (in 10{sup 15} molecules cm{sup -2}) of {approx}1 at 20 K and {approx}3 at 120 K. The initial yield is 0.05 (0.1) CO{sub 2} per incident H{sup +} at 20 (120) K. The CO{sub 2} destruction process, which limits the maximum column density, occurs with an effective cross section of {approx}2.5 (4.1) Multiplication-Sign 10{sup -17} cm{sup 2} at 20 (120) K. We discuss radiation-induced oxidation by reactions of radicals in water with the carbon surface and demonstrate that these reactions can be a significant source of condensed carbon dioxide in interstellar grains and in icy satellites in the outer solar system.

  3. On the state of water ice on saturn's moon Titan and implications to icy bodies in the outer solar system.

    PubMed

    Zheng, Weijun; Jewitt, David; Kaiser, Ralf I

    2009-10-22

    The crystalline state of water ice in the Solar System depends on the temperature history of the ice and the influence of energetic particles to which it has been exposed. We measured the infrared absorption spectra of amorphous and crystalline water ice in the 10-50 K and 10-140 K temperature ranges, respectively, and conducted a systematic experimental study to investigate the amorphization of crystalline water ice via ionizing radiation irradiation at doses of up to 160 +/- 30 eV per molecule. We found that crystalline water ice can be converted only partially to amorphous ice by electron irradiation. The experiments showed that a fraction of the 1.65 microm band, which is characteristic for crystalline water ice, survived the irradiation, to a degree that strongly depends on the temperature. Quantitative kinetic fits of the temporal evolution of the 1.65 mum band clearly demonstrate that there is a balance between thermal recrystallization and irradiation-induced amorphization, with thermal recrystallizaton dominant at higher temperatures. Our experiments show the amorphization at 40 K was incomplete, in contradiction to Mastrapa and Brown's conclusion (Icarus 2006, 183, 207.). At 50 K, the recrystallization due to thermal effects is strong, and most of the crystalline ice survived. Temperatures of most icy objects in the Solar System, including Jovian satellites, Saturnian satellites (including Titan), and Kuiper Belt Objects, are equal to or above 50 K; this explains why water ice detected on those objects is mostly crystalline. PMID:19827849

  4. On-orbit modulation transfer function characterization of terra MODIS using the moon

    NASA Astrophysics Data System (ADS)

    Wang, Zhipeng; Choi, Taeyoung; Xiong, Xiaoxiong

    2011-10-01

    The on-orbit Modulation Transfer Function (MTF) of MODIS instrument can be accurately measured by its on-board SpectroRadiometirc Calibration Assembly (SRCA). For other Earth observing instruments without calibrators similar to SRCA, the sharp edge of moon provides a reasonable high-contrast target for their on-orbit MTF characterization. In this paper, we propose a procedure to measure MODIS on-orbit MTF from the moon image. For Terra MODIS, lunar calibration was performed nearly every month since its launch in 2000. For each lunar calibration, the images of the moon from multiple scans are taken and traced across the right edge to form an edge spread function (ESF). The ESF is used to calculate a line spread function (LSF) through differentiation. The MTF in along-scan direction is then derived through the Fourier Transform of the LSF. The same procedure can also be applied to MTF calculation in along-track direction. The results are compared with SRCA measured MTF, and the long-term trending of both MTF agrees. Lunar MTF characterization appears noisier mainly because of the non-uniformity of the moon surface and moderate spatial resolution of the moon image, which makes it difficult to accurately locate the circular lunar edge in sub-pixel level. Improvement of the current method is discussed in the end.

  5. Galileo view of Moon orbiting the Earth taken from 3.9 million miles

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Eight days after its encounter with the Earth, the Galileo spacecraft was able to look back and capture this remarkable view of the Moon in orbit about the Earth, taken from a distance of about 6.2 million kilometers (3.9 million miles). The picture was constructed from images taken through the violet, red, and 1.0-micron infrared filters. The Moon is in the foreground, moving from left to right. The brightly-colored Earth contrasts strongly with the Moon, which reflects only about one-third as much sunlight as the Earth. Contrast and color have been computer-enhanced for both objects to improve visibility. Antarctica is visible through clouds (bottom). The Moon's far side is seen; the shadowy indentation in the dawn terminator is the south-Pole/Aitken Basin, one of the largest and oldest lunar impact features. Alternate Jet Propulsion Laboratory (JPL) number is P-41508.

  6. Earth-Moon Libration Point Orbit Stationkeeping: Theory, Modeling and Operations

    NASA Technical Reports Server (NTRS)

    Folta, David C.; Pavlak, Thomas A.; Haapala, Amanda F.; Howell, Kathleen C.; Woodard, Mark A.

    2013-01-01

    Collinear Earth-Moon libration points have emerged as locations with immediate applications. These libration point orbits are inherently unstable and must be maintained regularly which constrains operations and maneuver locations. Stationkeeping is challenging due to relatively short time scales for divergence effects of large orbital eccentricity of the secondary body, and third-body perturbations. Using the Acceleration Reconnection and Turbulence and Electrodynamics of the Moon's Interaction with the Sun (ARTEMIS) mission orbit as a platform, the fundamental behavior of the trajectories is explored using Poincare maps in the circular restricted three-body problem. Operational stationkeeping results obtained using the Optimal Continuation Strategy are presented and compared to orbit stability information generated from mode analysis based in dynamical systems theory.

  7. Detecting Extrasolar Moons Akin to Solar System Satellites with an Orbital Sampling Effect

    NASA Astrophysics Data System (ADS)

    Heller, René

    2014-05-01

    Despite years of high accuracy observations, none of the available theoretical techniques has yet allowed the confirmation of a moon beyond the solar system. Methods are currently limited to masses about an order of magnitude higher than the mass of any moon in the solar system. I here present a new method sensitive to exomoons similar to the known moons. Due to the projection of transiting exomoon orbits onto the celestial plane, satellites appear more often at larger separations from their planet. After about a dozen randomly sampled observations, a photometric orbital sampling effect (OSE) starts to appear in the phase-folded transit light curve, indicative of the moons' radii and planetary distances. Two additional outcomes of the OSE emerge in the planet's transit timing variations (TTV-OSE) and transit duration variations (TDV-OSE), both of which permit measurements of a moon's mass. The OSE is the first effect that permits characterization of multi-satellite systems. I derive and apply analytical OSE descriptions to simulated transit observations of the Kepler space telescope assuming white noise only. Moons as small as Ganymede may be detectable in the available data, with M stars being their most promising hosts. Exomoons with the ten-fold mass of Ganymede and a similar composition (about 0.86 Earth radii in radius) can most likely be found in the available Kepler data of K stars, including moons in the stellar habitable zone. A future survey with Kepler-class photometry, such as Plato 2.0, and a permanent monitoring of a single field of view over five years or more will very likely discover extrasolar moons via their OSEs.

  8. Detecting extrasolar moons akin to solar system satellites with an orbital sampling effect

    SciTech Connect

    Heller, René

    2014-05-20

    Despite years of high accuracy observations, none of the available theoretical techniques has yet allowed the confirmation of a moon beyond the solar system. Methods are currently limited to masses about an order of magnitude higher than the mass of any moon in the solar system. I here present a new method sensitive to exomoons similar to the known moons. Due to the projection of transiting exomoon orbits onto the celestial plane, satellites appear more often at larger separations from their planet. After about a dozen randomly sampled observations, a photometric orbital sampling effect (OSE) starts to appear in the phase-folded transit light curve, indicative of the moons' radii and planetary distances. Two additional outcomes of the OSE emerge in the planet's transit timing variations (TTV-OSE) and transit duration variations (TDV-OSE), both of which permit measurements of a moon's mass. The OSE is the first effect that permits characterization of multi-satellite systems. I derive and apply analytical OSE descriptions to simulated transit observations of the Kepler space telescope assuming white noise only. Moons as small as Ganymede may be detectable in the available data, with M stars being their most promising hosts. Exomoons with the ten-fold mass of Ganymede and a similar composition (about 0.86 Earth radii in radius) can most likely be found in the available Kepler data of K stars, including moons in the stellar habitable zone. A future survey with Kepler-class photometry, such as Plato 2.0, and a permanent monitoring of a single field of view over five years or more will very likely discover extrasolar moons via their OSEs.

  9. The moon as a radiometric reference source for on-orbit sensor stability calibration

    USGS Publications Warehouse

    Stone, T.C.

    2009-01-01

    The wealth of data generated by the world's Earth-observing satellites, now spanning decades, allows the construction of long-term climate records. A key consideration for detecting climate trends is precise quantification of temporal changes in sensor calibration on-orbit. For radiometer instruments in the solar reflectance wavelength range (near-UV to shortwave-IR), the Moon can be viewed as a solar diffuser with exceptional stability properties. A model for the lunar spectral irradiance that predicts the geometric variations in the Moon's brightness with ???1% precision has been developed at the U.S. Geological Survey in Flagstaff, AZ. Lunar model results corresponding to a series of Moon observations taken by an instrument can be used to stabilize sensor calibration with sub-percent per year precision, as demonstrated by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS). The inherent stability of the Moon and the operational model to utilize the lunar irradiance quantity provide the Moon as a reference source for monitoring radiometric calibration in orbit. This represents an important capability for detecting terrestrial climate change from space-based radiometric measurements.

  10. Access to Mars from Earth-Moon Libration Point Orbits:. [Manifold and Direct Options

    NASA Technical Reports Server (NTRS)

    Kakoi, Masaki; Howell, Kathleen C.; Folta, David

    2014-01-01

    This investigation is focused specifically on transfers from Earth-Moon L(sub 1)/L(sub 2) libration point orbits to Mars. Initially, the analysis is based in the circular restricted three-body problem to utilize the framework of the invariant manifolds. Various departure scenarios are compared, including arcs that leverage manifolds associated with the Sun-Earth L(sub 2) orbits as well as non-manifold trajectories. For the manifold options, ballistic transfers from Earth-Moon L(sub 2) libration point orbits to Sun-Earth L(sub 1)/L(sub 2) halo orbits are first computed. This autonomous procedure applies to both departure and arrival between the Earth-Moon and Sun-Earth systems. Departure times in the lunar cycle, amplitudes and types of libration point orbits, manifold selection, and the orientation/location of the surface of section all contribute to produce a variety of options. As the destination planet, the ephemeris position for Mars is employed throughout the analysis. The complete transfer is transitioned to the ephemeris model after the initial design phase. Results for multiple departure/arrival scenarios are compared.

  11. Trajectory Optimization for Crewed Missions to an Earth-Moon L2 Halo Orbit

    NASA Astrophysics Data System (ADS)

    Dowling, Jennifer

    Baseline trajectories to an Earth-Moon L2 halo orbit and round trip trajectories for crewed missions have been created in support of an advanced Orion mission concept. Various transfer durations and orbit insertion locations have been evaluated. The trajectories often include a deterministic mid-course maneuver that decreases the overall change in velocity in the trajectory. This paper presents the application of primer vector theory to study the existence, location, and magnitude of the mid-course maneuver in order to understand how to build an optimal round trip trajectory to an Earth-Moon L2 halo orbit. The lessons learned about when to add mid-course maneuvers can be applied to other mission designs.

  12. Exploring the Moon and Mars Using an Orbiting Superconducting Gravity Gradiometer

    NASA Technical Reports Server (NTRS)

    Paik, Ho Jung; Strayer, Donald M.

    2004-01-01

    Gravity measurement is fundamental to understanding the interior structure, dynamics, and evolution of planets. High-resolution gravity maps will also help locating natural resources, including subsurface water, and underground cavities for astronaut habitation on the Moon and Mars. Detecting the second spatial derivative of the potential, a gravity gradiometer mission tends to give the highest spatial resolution and has the advantage of requiring only a single satellite. We discuss gravity missions to the Moon and Mars using an orbiting Superconducting Gravity Gradiometer and discuss the instrument and spacecraft control requirements.

  13. Lunar capture orbits, a method of constructing earth moon trajectories and the lunar GAS mission. [Get Away Specials

    NASA Technical Reports Server (NTRS)

    Belbruno, E. A.

    1987-01-01

    A method is described to construct trajectories from the earth to the moon which utilizes the existence of lunar capture orbits and the concept of 'stability boundary'. These orbits are ballistic and represent a new family of trajectories. They go into orbit about the moon from a suitable position about the earth with no required thrusting. This method is applied to a mission being studied at JPL called Lunar GAS (Get Away Special). Other applications are discussed.

  14. Electric Properties of Water Ice doped with Hydrogen Peroxide (H2O2): Implications for Icy Moons such as Europa

    NASA Astrophysics Data System (ADS)

    Keller, C.; Freund, F. T.; Cruikshank, D. P.

    2012-12-01

    Large floats of ice on Jupiter's moon Europa drift and collide. The float boundaries are marked by brownish-reddish colors. The origin of these colors is poorly understood. Maybe upwelling of water along the active float boundaries brings finely divided suspended matter or organic compounds from the ocean below to the surface, where the intense, high energy environment in Jupiter's radiation belt would lead to photochemical oxidation. At the same time it has been suggested that Europa's ice contains traces of H2O2, presumably due to micro-meteorite impacts and other processes. We measured the electric currents generated in pure and H2O2-doped water ice when we subjected one end of ice blocks to uniaxial stress. Ice samples with 0%, 0.3% and 0.03% H2O2 were formed in polyethylene troughs, 4.1 x 13.5 x 3.8 cm, with Cu contacts at both ends, at 263K (-10°C), 190K (-78°C, dry ice) and 77K (-196°C,liquid N2). At 77K the ice samples detached themselves from at least one of the Cu contacts, due to thermal contraction. At 190K, when stressing one end, essentially no currents were produced in the pure water ice. By contrast, H2O2-doped ices produced several hundred picoamperes (pA) of positive currents, indicating defect electrons (holes) flowing down the stress gradient. At 263K the results are ambiguous. These (as yet preliminary) results indicate that stresses might break the peroxy bonds of imbedded H2O2 molecules, releasing the same type of positive hole charge carriers as observed during stress experiments with silicate rocks. Since positive holes are defect electrons associated with O 2sp levels at the upper edge of the valence band, they seem to have the capability to spread through the ices. Chemically positive holes are equivalent to highly oxidizing oxygen radicals. They may be responsible for oxidation reactions along the boundaries of active ice floats on Europa.

  15. Low-Thrust Transfers from Distant Retrograde Orbits to L2 Halo Orbits in the Earth-Moon System

    NASA Technical Reports Server (NTRS)

    Parrish, Nathan L.; Parker, Jeffrey S.; Hughes, Steven P.; Heiligers, Jennette

    2016-01-01

    Enable future missions Any mission to a DRO or halo orbit could benefit from the capability to transfer between these orbits Chemical propulsion could be used for these transfers, but at high propellant cost Fill gaps in knowledge A variety of transfers using SEP or solar sails have been studied for the Earth-Moon system Most results in literature study a single transfer This is a step toward understanding the wide array of types of transfers available in an N-body force model.

  16. The Homoclinic and Heteroclinic Connections of Planar Symmetric Resonant Orbits in the Restricted Three-Body Earth-Moon System

    NASA Astrophysics Data System (ADS)

    Peng, Chao

    2016-07-01

    This study presents planar symmetric resonant orbits in the restricted three-body Earth-Moon system and their homoclinic and heteroclinic connections in the vicinity of the Moon are analyzed in details. In the rotating coordinate frame of the circular restricted three-body problem, there exist planar periodic orbits that appear symmetric about the line connecting the Earth and the Moon. The orbital periods of these orbits demonstrate approximately p:q resonance with respect to the Moon (a spacecraft completes p orbits while the Moon completes q orbits around the Earth in the same time interval). For a specified resonant ratio, four cases of these symmetric resonant orbits (those with resonant ratios of 1:1, 1:2, 1:3, 2:1, 2:3, 3:1, 3:2, 3:4 are presented as examples) are defined and computed in the restricted three-body Earth-Moon system. We focus our attention on those resonant orbits that pass through the vicinity of the Moon and compute the corresponding stable and unstable invariant manifolds. Poincare maps are plotted by observing the orbital states of resonant orbits at perilunes and we then identify the presence of the homoclinic connection and the heteroclinic connection. This characteristic of orbital transfers might provide a means for observing the Moon's low-latitude regions with different longitudes and the insertion into lunar orbitis not necessary. Besides, other potential utilizations of the homoclinic and heteroclinic connections for fully making use of lunar gravity assist are also discussed.

  17. Low-Thrust Transfers from Distant Retrograde Orbits to L2 Halo Orbits in the Earth-Moon System

    NASA Technical Reports Server (NTRS)

    Parrish, Nathan L.; Parker, Jeffrey S.; Hughes, Steven P.; Heiligers, Jeannette

    2016-01-01

    This paper presents a study of transfers between distant retrograde orbits (DROs) and L2 halo orbits in the Earth-Moon system that could be flown by a spacecraft with solar electric propulsion (SEP). Two collocation-based optimal control methods are used to optimize these highly-nonlinear transfers: Legendre pseudospectral and Hermite-Simpson. Transfers between DROs and halo orbits using low-thrust propulsion have not been studied previously. This paper offers a study of several families of trajectories, parameterized by the number of orbital revolutions in a synodic frame. Even with a poor initial guess, a method is described to reliably generate families of solutions. The circular restricted 3-body problem (CRTBP) is used throughout the paper so that the results are autonomous and simpler to understand.

  18. Estimates of the moon's geometry using lunar orbiter imagery and Apollo laser altimeter data

    NASA Technical Reports Server (NTRS)

    Jones, R. L.

    1973-01-01

    Selenographic coordinates for about 6000 lunar points identified on the Lunar Orbiter photographs are tabulated and have been combined with those lunar radii derived from the Apollo 15 laser altimeter data. These coordinates were used to derive that triaxial ellipsoid which best fits the moon's irregular surface. Fits were obtaind for different constraints on both the axial orientations and the displacement of the center of the ellipsoid. The semiaxes for the unconstrained ellipsoid were a = 1737.6 km, b = 1735.6 km, and c = 1735.0 km which correspond to a mean radius of about 1736.1 km. These axes were found to be nearly parallel to the moon's principal axes of inertia, and the origin was displaced about 2.0 km from the moon's center of gravity in a direction away from the earth and to the south of the lunar equator.

  19. Transfers to distant periodic orbits around the Moon via their invariant manifolds

    NASA Astrophysics Data System (ADS)

    Mingotti, G.; Topputo, F.; Bernelli-Zazzera, F.

    2012-10-01

    This paper presents two ways to transfer a spacecraft to distant periodic orbits in the Earth-Moon system. These unstable periodic orbits of the restricted three-body problem reveal a rich phase-portrait structure that can be used by space missions. Through the perspective of dynamical system theory, distant periodic orbits' invariant manifolds can be exploited to design novel low-energy trajectories in the Earth-Moon framework. Interior and exterior transfers are presented. The latter use impulsive, high-thrust propulsion to target the stable manifold from the exterior. Interior transfers are instead formulated with continuous, low-thrust propulsion. The attainable sets are used in both cases to handle families of either coast arcs or low-thrust orbits. First guess solutions are optimized in the framework of the Sun-Earth-Moon-Spacecraft restricted four-body problem through direct transcription and multiple shooting. The novelty of the presented solutions, as well as their efficiency, is demonstrated through examples.

  20. Autonomous optical navigation for orbits around Earth-Moon collinear libration points

    NASA Astrophysics Data System (ADS)

    Virgili Llop, Josep

    2013-05-01

    The analysis of optical navigation in an Earth-Moon libration point orbit is examined. Missions to libration points have been winning momentum during the last decades. Its unique characteristics make it suitable for a number of operational and scientific goals. Literature aimed to study dynamics, guidance and control of unstable orbits around collinear libration points is vast. In particular, several papers deal with the optimisation of the Δv budget associated to the station-keeping of these orbits. One of the results obtained in literature establishes the critical character of the Moon-Earth system in this aspect. The reason for this behaviour is twofold: high Δv cost and short optimal manoeuvre spacing. Optical autonomous navigation can address the issue of allowing a more flexible manoeuvre design. This technology has been selected to overcome similar difficulties in other critical scenarios. This paper analyses in detail this solution. A whole GNC system is defined to meet the requirements imposed by the unstable dynamic environment. Finally, a real simulation of a spacecraft following a halo orbit of the L2 Moon-Earth system is carried out to assess the actual capabilities of the optical navigation in this scenario.

  1. Millimeter Laser Ranging to the Moon: prospects and challenges in improving the orbital and rotational dynamics

    NASA Astrophysics Data System (ADS)

    Kopeikin, S.; Pavlis, E.; Pavlis, D.

    2008-09-01

    ABSTRACT Lunar Laser Ranging (LLR) measurements are crucial for advanced exploration of the laws of fundamental gravitational physics and geophysics as well as for future human and robotic missions to the Moon. The corner-cube reflectors (CCR) currently on the Moon require no power and still work perfectly since their installation during the project Apollo era. Current LLR technology allows us to measure distances to the Moon with a precision approaching one millimeter [1]. As NASA, ESA, and other space agencies pursues the vision of taking humans back to the Moon, new, more precise laser ranging applications will be demanded, including continuous tracking from more sites on Earth, placing new CCR arrays on the Moon, and possibly installing other devices such as transponders, etc. for multiple scientific and technical purposes [2]. Since this effort involves humans in space, then in all situations the accuracy, fidelity, and robustness of the measurements, their adequate interpretation, and any products based on them, are of utmost importance. Successful achievement of this goal strongly demands further significant improvement of the theoretical model of the orbital and rotational dynamics of the Earth-Moon system. This model should inevitably be based on the theory of general relativity, fully incorporate the relevant geophysical processes, lunar librations, tides, and should rely upon the most recent standards and recommendations of the IAU for data analysis [3]. This talk discusses theoretical ideas, methods and challenges in developing such an advanced mathematical model. The model will take into account all the classical and relativistic effects in the orbital and rotational motion of the Moon and Earth at the millimeter precision. The model is supposed to be implemented as a part of the computer code underlying NASA Goddard's orbital analysis and geophysical parameter estimation package GEODYN [4]. The new model will allow us to make more precise altimetry of

  2. The Earth transiting the Sun as seen from Jupiter's moons: detection of an inverse Rossiter-McLaughlin effect produced by the opposition surge of the icy Europa

    NASA Astrophysics Data System (ADS)

    Molaro, P.; Barbieri, M.; Monaco, L.; Zaggia, S.; Lovis, C.

    2015-10-01

    We report on a multiwavelength observational campaign which followed the Earth's transit on the Sun as seen from Jupiter on 2014 January 2014. Simultaneous observations of Jupiter's moons Europa and Ganymede obtained with high accuracy radial velocity planetary searcher (HARPS) from La Silla, Chile and HARPS-N from La Palma, Canary Islands were performed to measure the Rossiter-McLaughlin effect due to the Earth's passage using the same technique successfully adopted for the 2012 Venus Transit. The expected modulation in radial velocities was of ≈20 cm s-1 but an anomalous drift as large as ≈38 m s-1, i.e. more than two orders of magnitude higher and opposite in sign, was detected instead. The consistent behaviour of the two spectrographs rules out instrumental origin of the radial velocity drift and Birmingham Solar Oscillations Network observations rule out the possible dependence on the Sun's magnetic activity. We suggest that this anomaly is produced by the opposition surge on Europa's icy surface, which amplifies the intensity of the solar radiation from a portion of the solar surface centred around the crossing Earth which can then be observed as a sort of inverse Rossiter-McLaughlin effect. in fact, a simplified model of this effect can explain in detail most features of the observed radial velocity anomalies, namely the extensions before and after the transit, the small differences between the two observatories and the presence of a secondary peak closer to Earth passage. This phenomenon, observed here for the first time, should be observed every time similar Earth alignments occur with rocky bodies without atmospheres. We predict that it should be observed again during the next conjunction of Earth and Jupiter in 2026.

  3. Use of the moon to support on-orbit sensor calibration for climate change measurements

    USGS Publications Warehouse

    Stone, T.C.; Kieffer, H.H.

    2006-01-01

    Production of reliable climate datasets from multiple observational measurements acquired by remote sensing satellite systems available now and in the future places stringent requirements on the stability of sensors and consistency among the instruments and platforms. Detecting trends in environmental parameters measured at solar reflectance wavelengths (0.3 to 2.5 microns) requires on-orbit instrument stability at a level of 1% over a decade. This benchmark can be attained using the Moon as a radiometric reference. The lunar calibration program at the U.S. Geological Survey has an operational model to predict the lunar spectral irradiance with precision ???1%, explicitly accounting for the effects of phase, lunar librations, and the lunar surface photometric function. A system for utilization of the Moon by on-orbit instruments has been established. With multiple lunar views taken by a spacecraft instrument, sensor response characterization with sub-percent precision over several years has been achieved. Meteorological satellites in geostationary orbit (GEO) capture the Moon in operational images; applying lunar calibration to GEO visible-channel image archives has the potential to develop a climate record extending decades into the past. The USGS model and system can provide reliable transfer of calibration among instruments that have viewed the Moon as a common source. This capability will be enhanced with improvements to the USGS model absolute scale. Lunar calibration may prove essential to the critical calibration needs to cover a potential gap in observational capabilities prior to deployment of NPP/NPOESS. A key requirement is that current and future instruments observe the Moon.

  4. The Lunar Reconnaissance Orbiter Mission - Six years of science and exploration at the Moon

    NASA Astrophysics Data System (ADS)

    Keller, J. W.; Petro, N. E.; Vondrak, R. R.

    2016-07-01

    Since entering lunar orbit on June 23, 2009 the Lunar Reconnaissance Orbiter (LRO) has made comprehensive measurements of the Moon and its environment. The seven LRO instruments use a variety of primarily remote sensing techniques to obtain a unique set of observations. These measurements provide new information regarding the physical properties of the lunar surface, the lunar environment, and the location of volatiles and other resources. Scientific interpretation of these observations improves our understanding of the geologic history of the Moon, its current state, and what its history can tell us about the evolution of the Solar System. Scientific results from LRO observations overturned existing paradigms and deepened our appreciation of the complex nature of our nearest neighbor. This paper summarizes the capabilities, measurements, and some of the science and exploration results of the first six years of the LRO mission.

  5. Operating the Dual-Orbiter GRAIL Mission to Measure the Moon's Gravity

    NASA Technical Reports Server (NTRS)

    Beerer, Joseph G.; Havens, Glen G.

    2012-01-01

    NASA's mission to measure the Moon's gravity and determine the interior structure, from crust to core, has almost completed its 3-month science data collection phase. The twin orbiters of the Gravity Recovery and Interior Laboratory (GRAIL) mission were launched from Florida on September 10, 2011, on a Delta-II launch vehicle. After traveling for nearly four months on a low energy trajectory to the Moon, they were inserted into lunar orbit on New Year's Eve and New Year's Day. In January 2012 a series of circularization maneuvers brought the orbiters into co-planar near-circular polar orbits. In February a distant (75- km) rendezvous was achieved and the science instruments were turned on. A dual- frequency (Ka and S-band) inter-orbiter radio link provides a precise orbiter-to-orbiter range measurement that enables the gravity field estimation. NASA's Jet Propulsion Laboratory in Pasadena, CA, manages the GRAIL project. Mission management, mission planning and sequencing, and navigation are conducted at JPL. Lockheed Martin, the flight system manufacturer, operates the orbiters from their control center in Denver, Colorado. The orbiters together have performed 28 propulsive maneuvers to reach and maintain the science phase configuration. Execution of these maneuvers, as well as the payload checkout and calibration activities, has gone smoothly due to extensive pre-launch operations planning and testing. The key to the operations success has been detailed timelines for product interchange between the operations teams and proven procedures from previous JPL/LM planetary missions. Once in science phase, GRAIL benefitted from the payload operational heritage of the GRACE mission that measures the Earth's gravity.

  6. A Venus-mass Planet Orbiting a Brown Dwarf: A Missing Link between Planets and Moons

    NASA Astrophysics Data System (ADS)

    Udalski, A.; Jung, Y. K.; Han, C.; Gould, A.; Kozłowski, S.; Skowron, J.; Poleski, R.; Soszyński, I.; Pietrukowicz, P.; Mróz, P.; Szymański, M. K.; Wyrzykowski, Ł.; Ulaczyk, K.; Pietrzyński, G.; Shvartzvald, Y.; Maoz, D.; Kaspi, S.; Gaudi, B. S.; Hwang, K.-H.; Choi, J.-Y.; Shin, I.-G.; Park, H.; Bozza, V.

    2015-10-01

    The co-planarity of solar system planets led Kant to suggest that they formed from an accretion disk, and the discovery of hundreds of such disks around young stars as well as hundreds of co-planar planetary systems by the Kepler satellite demonstrate that this formation mechanism is extremely widespread. Many moons in the solar system, such as the Galilean moons of Jupiter, also formed out of the accretion disks that coalesced into the giant planets. Here we report the discovery of an intermediate system, OGLE-2013-BLG-0723LB/Bb, composed of a Venus-mass planet orbiting a brown dwarf, which may be viewed either as a scaled-down version of a planet plus a star or as a scaled-up version of a moon plus a planet orbiting a star. The latter analogy can be further extended since they orbit in the potential of a larger, stellar body. For ice-rock companions formed in the outer parts of accretion disks, like Uranus and Callisto, the scaled masses and separations of the three types of systems are similar, leading us to suggest that the formation processes of companions within accretion disks around stars, brown dwarfs, and planets are similar.

  7. Doubly-periodic orbits in the Sun-Earth-Moon system

    NASA Technical Reports Server (NTRS)

    Farohar, R.; Muhonen, D.; Dunham, D.

    1980-01-01

    A series of periodic orbits in the Earth-Moon circular restricted problem of three bodies was found which is ideally suited for exploring the Earth's geomagnetic tail. The mean apsidal motion of the basic highly elliptical Earth orbit was maintained at about one degree per day by a sequence of lunar swingbys, keeping the apogees in the anti-Sun direction. The orbits were periodic in reference frames rotating at both lunar and solar rates. Apogee distances were alternately raised and lowered by the lunar swingby maneuvers. Several categories of these Sun-synchronous double lunar swingby orbits were identified. The strength and flexibility of this trajectory concept was demonstrated with real world simulations.

  8. NPP VIIRS On-Orbit Calibration and Characterization Using the Moon

    NASA Technical Reports Server (NTRS)

    Sun, J.; Xiong, X.; Butler, J.

    2012-01-01

    The Visible Infrared Imager Radiometer Suite (VIIRS) is one of five instruments on-board the Suomi National Polar orbiting Partnership (NPP) satellite that launched from Vandenberg Air Force Base, Calif., on Oct. 28, 2011. VIIRS has been scheduled to view the Moon approximately monthly with a spacecraft roll maneuver after its NADIR door open on November 21, 2011. To reduce the uncertainty of the radiometric calibration due to the view geometry, the lunar phase angles of the scheduled lunar observations were confined in the range from -56 deg to -55 deg in the first three scheduled lunar observations and then changed to the range from -51.5 deg to -50.5 deg, where the negative sign for the phase angles indicates that the VIIRS views a waxing moon. Unlike the MODIS lunar observations, most scheduled VIIRS lunar views occur on the day side of the Earth. For the safety of the instrument, the roll angles of the scheduled VIIRS lunar observations are required to be within [-14 deg, 0 deg] and the aforementioned change of the phase angle range was aimed to further minimize the roll angle required for each lunar observation while keeping the number of months in which the moon can be viewed by the VIIRS instrument each year unchanged. The lunar observations can be used to identify if there is crosstalk in VIIRS bands and to track on-orbit changes in VIIRS Reflective Solar Bands (RSB) detector gains. In this paper, we report our results using the lunar observations to examine the on-orbit crosstalk effects among NPP VIIRS bands, to track the VIIRS RSB gain changes in first few months on-orbit, and to compare the gain changes derived from lunar and SD/SDSM calibration.

  9. Polyhedral representation of invariant manifolds applied to orbit transfers in the Earth-Moon system

    NASA Astrophysics Data System (ADS)

    Pontani, Mauro; Teofilatto, Paolo

    2016-02-01

    Recently, manifold dynamics has assumed an increasing relevance for analysis and design of low-energy missions, both in the Earth-Moon system and in alternative multibody environments. This work proposes and describes an intuitive polyhedral interpolative approach for each state component associated with manifold trajectories, both in two and in three dimensions. An adequate grid of data, coming from the numerical propagation of a finite number of manifold trajectories, is employed. Accuracy of this representation is evaluated with reference to the invariant manifolds associated with a two-dimensional Lyapunov orbit and a three-dimensional Halo orbit, and is proven to be satisfactory, with the exclusion of limited regions of the manifolds. As a first, preliminary application, the polyhedral interpolation technique allows identifying the orbits in the proximity of the interior collinear libration point as either asymptotic, transit, or bouncing trajectories. Then, two applications to orbital maneuvering are addressed. First, the globally optimal two-impulse transfer between a specified low Earth orbit and a Lyapunov orbit (through its stable manifold) is determined. Second, the minimum-time low-thrust transfer from the same terminal orbits is found using again the stable manifold. These applications prove the effectiveness of the polyhedral interpolative technique and represent the premise for its application also to different problems involving invariant manifold dynamics.

  10. Apollo 16 view of moon taken with Fairchild metric mapping camera in orbit

    NASA Technical Reports Server (NTRS)

    1972-01-01

    A newly-analyzed photograph of the southwest quadrant of the Moon with an overlay indicating where the launch vehicle stages from two Apollo missions, 13 and 14, hit the lunar surface. This is the first time two S-IVB stage impact points have been located in a single photo. The S-IVB stage is the thrid stage of the Saturn V launch vehicle. The Riphaeus Mountains run northward between the two impact points. The fresh, raised-rim crater at center left is Euclides; and the largest crater near the horizon at upper left is Landberg. The mare area at lower right is the Known Sea. The photograph was taken by the Apollo 16 Fairchild metric mapping camera in lunar orbit, at a 40-degree north oblique angle. The picture was taken during the Apollo 16 Command/Service Module's 59th revolution of the Moon, at an altitude of 124 kilometers. The Sun elevation was 18 degrees.

  11. Evidence of recent thrust faulting on the Moon revealed by the Lunar Reconnaissance Orbiter Camera.

    PubMed

    Watters, Thomas R; Robinson, Mark S; Beyer, Ross A; Banks, Maria E; Bell, James F; Pritchard, Matthew E; Hiesinger, Harald; van der Bogert, Carolyn H; Thomas, Peter C; Turtle, Elizabeth P; Williams, Nathan R

    2010-08-20

    Lunar Reconnaissance Orbiter Camera images reveal previously undetected lobate thrust-fault scarps and associated meter-scale secondary tectonic landforms that include narrow extensional troughs or graben, splay faults, and multiple low-relief terraces. Lobate scarps are among the youngest landforms on the Moon, based on their generally crisp appearance, lack of superposed large-diameter impact craters, and the existence of crosscut small-diameter impact craters. Identification of previously known scarps was limited to high-resolution Apollo Panoramic Camera images confined to the equatorial zone. Fourteen lobate scarps were identified, seven of which are at latitudes greater than +/-60 degrees, indicating that the thrust faults are globally distributed. This detection, coupled with the very young apparent age of the faults, suggests global late-stage contraction of the Moon. PMID:20724632

  12. Discussion paper on environmental hazards on the Moon, in low Earth orbit, and in low Mars orbit

    SciTech Connect

    Heiken, G.

    1990-09-01

    In a lunar base era, potential problems with dust will be serious. Lunar soils, which make up most of the regolith that covers the Moon's surface, are similar to silty sands on Earth, with mean grain sizes of 45--100 {mu}m. Lunar dust has very low electrical conductivity and dielectric losses, permitting accumulation of electric charge under ultraviolet irradiation. Dust coatings cover thermally-sensitive surfaces, windows and visors, clog moving parts, and create continual abrasion hazards. Reduced gravity on the Moon favors the stability of aerosolized lunar soil and thereby will prolong its availability for inhalation if it is not removed from habitat atmosphere by filtration systems. Some of the other hazards that must be considered include: Perception; on the lunar surface it is difficult to judge topographic details and distances, and Micrometeoroid impact; new materials are needed to protect astronauts and equipment at a lunar base. Spacecraft in low orbits around Earth and Mars experience strong chemical interactions where O{sub 2} and CO{sub 2} are photodissociated by sunlight. A ground-based facility at Los Alamos can be used to test these chemical interactions with materials proposed for use in spacecraft and satellites. Another component of the space exploration initiative is the environmental effects posed by man on the tenuous lunar and martian atmospheres. Before significant development occurs on these planets, these atmospheres must be measured. Orbiting sensors designed to measure these atmospheres can also be used to search for water.

  13. NPP VIIRS on-orbit calibration and characterization using the moon

    NASA Astrophysics Data System (ADS)

    Sun, J.; Xiong, X.; Butler, J.

    2012-09-01

    The Visible Infrared Imager Radiometer Suite (VIIRS) is one of five instruments on-board the Suomi National Polarorbiting Partnership (NPP) satellite that launched from Vandenberg Air Force Base, Calif., on Oct. 28, 2011. VIIRS has been scheduled to view the Moon approximately monthly with a spacecraft roll maneuver after its NADIR door open on November 21, 2012. To reduce the uncertainty of the radiometric calibration due to the view geometry, the lunar phase angles of the scheduled lunar observations were confined in the range from -56° to -55° in the first three scheduled lunar observations and then changed to the range from -51.5° to -50.5°, where the negative sign for the phase angles indicates that the VIIRS views a waxing moon. Unlike the MODIS lunar observations, most scheduled VIIRS lunar views occur on the day side of the Earth. For the safety of the instrument, the roll angles of the scheduled VIIRS lunar observations are required to be within [-14°, 0°] and the aforementioned change of the phase angle range was aimed to further minimize the roll angle required for each lunar observation while keeping the number of months in which the moon can be viewed by the VIIRS instrument each year unchanged. The lunar observations can be used to identify if there is crosstalk in VIIRS bands and to track on-orbit changes in VIIRS Reflective Solar Bands (RSB) detector gains. In this paper, we report our results using the lunar observations to examine the on-orbit crosstalk effects among NPP VIIRS bands, to track the VIIRS RSB gain changes in first few months on-orbit, and to compare the gain changes derived from lunar and SD/SDSM calibration.

  14. Effects of physical librations of the moon on the orbital elements of a lunar satellite.

    NASA Technical Reports Server (NTRS)

    Ferrari, A. J.; Heffron, W. G.

    1973-01-01

    Physical librations of the moon are small cyclic perturbations with periods of one month and longer, and amplitudes of 100 arc seconds or less. This paper gives data on the magnitude of the physical librations, the geometrical effects on the orbital elements, and the equivalent changes in the coefficients in the gravitational potential. It is shown that geometrical effects can be accommodated either by using an inertial axes system or by compensating for the lunar librations and precession when the selenographic axes are used. Further, it is shown that physical effects are small and negligible for all but the most exacting endeavors.

  15. On-Orbit Cross-Calibration of AM Satellite Remote Sensing Instruments using the Moon

    NASA Technical Reports Server (NTRS)

    Butler, James J.; Kieffer, Hugh H.; Barnes, Robert A.; Stone, Thomas C.

    2003-01-01

    On April 14,2003, three Earth remote sensing spacecraft were maneuvered enabling six satellite instruments operating in the visible through shortwave infrared wavelength region to view the Moon for purposes of on-orbit cross-calibration. These instruments included the Moderate Resolution Imaging Spectroradiometer (MODIS), the Multi-angle Imaging SpectroRadiometer (MISR), the Advanced Spaceborne Thermal Emission and Reflection (ASTER) radiometer on the Earth Observing System (EOS) Terra spacecraft, the Advanced Land Imager (ALI) and Hyperion instrument on Earth Observing-1 (EO-1) spacecraft, and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) on the SeaStar spacecraft. Observations of the Moon were compared using a spectral photometric mode for lunar irradiance developed by the Robotic Lunar Observatory (ROLO) project located at the United States Geological Survey in Flagstaff, Arizona. The ROLO model effectively accounts for variations in lunar irradiance corresponding to lunar phase and libration angles, allowing intercomparison of observations made by instruments on different spacecraft under different time and location conditions. The spacecraft maneuvers necessary to view the Moon are briefly described and results of using the lunar irradiance model in comparing the radiometric calibration scales of the six satellite instruments are presented here.

  16. Orbit optimization of Chang'E-2 by global adjustment using images of the moon

    NASA Astrophysics Data System (ADS)

    Yan, Wei; Liu, Jianjun; Ren, Xin; Wang, Fenfei; Wang, Wenrui; Li, Chunlai

    2015-12-01

    The orbit accuracy of the Chang'E-2 (CE-2) lunar probe is one of the most critical factors for a seamless mosaic of the global lunar topographic map. During the production of the CE-2 global lunar topographic map, a maximum deviation of kilometers magnitude existed in the horizontal direction of homologous points between neighboring images, while the maximum height deviation of these points is up to several hundred meters. This phenomenon indicates that current orbit determination results of CE-2 cannot truly reflect the relative position relationship between probe and lunar surface features. Against this background, global adjustment using images of the moon should be carried out to solve this problem. In this paper, the influence of CE-2 current orbit accuracy on the production of a global lunar topographic map will be analyzed based on the introduction of CE-2 observation data, including images and orbit data. Additionally, key technologies and technical processes of global adjustment using CE-2 images with high-resolution and large amounts of data will be researched. Finally, orbit optimization of CE-2 after global adjustment is analyzed, as well as the accuracy of the CE-2 global lunar topographic map for validation verification.

  17. A possible space VLBI constellation utilizing the stable orbits around the TLPs in the Earth-Moon system.

    NASA Astrophysics Data System (ADS)

    Liu, Bin; Tang, Jingshi; Hou, Xiyun

    2016-07-01

    Current studies indicate that there are stable orbits around but far away from the triangular libration points .Two special quasi-periodic orbits around each triangular libration points L4 , L5 in the Earth-Moon sys-tem perturbed by Sun are gain , and the stable orbits discussed in this work are ideal places for space colonies because no orbit control is needed. These stable orbits can also be used as nominal orbits for space VLBI (Very Long Baseline Interferometry) stations. The two stations can also form baselines with stations on the Earth and the Moon, or with stations located around another TLP. Due to the long distance between the stations, the observation precision can be greatly enhanced compared with the VLBI stations on the Earth. Such a VLBI constellation not only can advance the radio astronomy, but also can be used as a navigation system for human activities in the Earth-Moon system and even in the solar system. This paper will focus on the navigation constellation coverage issues, and the orbit determination accuracy problems within the Earth-Moon sys-tem and interplanetary space.

  18. Overview of a Preliminary Destination Mission Concept for a Human Orbital Mission to the Martial Moons

    NASA Technical Reports Server (NTRS)

    Mazanek, D. D.; Abell, P. A.; Antol, J.; Barbee, B. W.; Beaty, D. W.; Bass, D. S.; Castillo-Rogez, J. C.; Coan, D. A.; Colaprete, A.; Daugherty, K. J.; Drake, B. G.; Earle, K. D.; Graham, L. D.; Hembree, R. M.; Hoffman, S. J.; Jefferies, S. A.; Lupisella, M. L.; Reeves, David M.

    2012-01-01

    The National Aeronautics and Space Administration s Human Spaceflight Architecture Team (HAT) has been developing a preliminary Destination Mission Concept (DMC) to assess how a human orbital mission to one or both of the Martian moons, Phobos and Deimos, might be conducted as a follow-on to a human mission to a near-Earth asteroid (NEA) and as a possible preliminary step prior to a human landing on Mars. The HAT Mars-Phobos-Deimos (MPD) mission also permits the teleoperation of robotic systems by the crew while in the Mars system. The DMC development activity provides an initial effort to identify the science and exploration objectives and investigate the capabilities and operations concepts required for a human orbital mission to the Mars system. In addition, the MPD Team identified potential synergistic opportunities via prior exploration of other destinations currently under consideration.

  19. Weather, moons, and orbit of the brown dwarf Gl 229B

    NASA Astrophysics Data System (ADS)

    Burrows, Christopher

    1999-07-01

    Gl 229B is the only unambiguous brown dwarf. It can be imaged with high astrometric and photometric accuracy only by HST. For the first time, we have an opportunity to study the object over an extended period of time. The possibilities for detecting planets or moons orbiting Gl 229B are quite promising because Gl 229B's small size, mass, and distance from us amplify the expected signals. We will be able to detect a companion if it is almost as small as Earth, and in a close orbit {similar to those occupied by Jupiter's moons} that is favourably inclined. Such a body in such an orbit might well have formed in the accretion disk from which Gl 229B grew. On the other hand, a higher mass companion in a wider orbit will be detected by the reflex motion it induces on Gl 229B itself, with a search radius limited only by the time baseline over which the observations are carried out. Any detection of a companion will allow the immediate determination of the mass of Gl 229B. An additional benefit of the monitoring proposed here is that if there are stationary and long lived surface features on Gl 229B like Jupiter's giant red spot, we will detect them and hence measure the rotation period of the brown dwarf. Finally, variations in the intrinsic luminosity could be caused by weather in its highly convective atmosphere. Even if no planetary companion is detected, this proposal will establish the variability or lack thereof of this unique object.

  20. Quantum effects on Lagrangian points and displaced periodic orbits in the Earth-Moon system

    NASA Astrophysics Data System (ADS)

    Battista, Emmanuele; Dell'Agnello, Simone; Esposito, Giampiero; Simo, Jules

    2015-04-01

    Recent work in the literature has shown that the one-loop long distance quantum corrections to the Newtonian potential imply tiny but observable effects in the restricted three-body problem of celestial mechanics; i.e., at the Lagrangian libration points of stable equilibrium, the planetoid is not exactly at an equal distance from the two bodies of large mass, but the Newtonian values of its coordinates are changed by a few millimeters in the Earth-Moon system. First, we assess such a theoretical calculation by exploiting the full theory of the quintic equation, i.e., its reduction to Bring-Jerrard form and the resulting expression of roots in terms of generalized hypergeometric functions. By performing the numerical analysis of the exact formulas for the roots, we confirm and slightly improve the theoretical evaluation of quantum corrected coordinates of Lagrangian libration points of stable equilibrium. Second, we prove in detail that for collinear Lagrangian points the quantum corrections are also of the same order of magnitude in the Earth-Moon system. Third, we discuss the prospects of measuring, with the help of laser ranging, the above departure from the equilateral triangle picture, which is a challenging task. On the other hand, a modern version of the planetoid is the solar sail, and much progress has been made, in recent years, on the displaced periodic orbits of solar sails at all libration points, both stable and unstable. Therefore, the present paper investigates, eventually, a restricted three-body problem involving Earth, the Moon, and a solar sail. By taking into account the one-loop quantum corrections to the Newtonian potential, displaced periodic orbits of the solar sail at libration points are again found to exist.

  1. Measurement of Surface Composition for the Icy Galilean Moons Via Neutral and Ion Mass Spectrometry from Orbit with JIMO

    NASA Technical Reports Server (NTRS)

    Wong, M.; Berthelier, J.; Carlson, R.; Cooper, J.; Johnson, R.; Jurac, S.; Leblanc, F.; Shematovich, V.

    2003-01-01

    In this paper, we will provide insights into mass spectrometer requirements. In addition, we will describe the modeling of the neutrals ejected from likely surface materials and their ionization rates in the Jovian environment. We will use such models to connect the mass spectra measurements of the freshly formed ions to surface composition. We will also discuss what possible compositional signatures are for endogenic materials other than water ice. Finally, since a goal is to identify material composition with surface features, we will describe the transport of neutrals ejected from the surface prior to detection by either an ion or neutral mass spectrometer.

  2. The Lunar Reconnaissance Orbiter Mission: Seven Years at the Moon - Accomplishments, Data, and Future Prospects

    NASA Astrophysics Data System (ADS)

    Petro, Noah; Keller, John

    2016-07-01

    The LRO Spacecraft has been orbiting the Moon for over 7 years (~91 lunations), and in that time data from the seven instruments has contributed to a revolution in our understanding of the Moon. Since launch the mission goals and instruments science questions have evolved, from the initial characterization of the lunar surface and its environment to studying the variability of surface hydration and measuring the flux of new craters that have formed during LRO's time in lunar orbit. The growing LRO dataset in the PDS presents a unique archive that allows for an unprecedented opportunity to study how an airless body changes over time. The LRO instrument suite [1] is performing nominally, with no significant performance issues since the mission entered the current extended mission. The Mini-RF instrument team is investigating new methods for collecting bistatic data using an Earth-based X-band transmitter [2] during a possible upcoming extended mission starting in September 2016, pending NASA approval. The LRO spacecraft has been in an elliptical, polar orbit with a low perilune over the South Pole since December 2011. This orbit minimizes annual fuel consumption, enabling LRO to use fuel to maximize opportunities for obtaining unique science (e.g., lunar eclipse measurements from Diviner, measuring spacecraft impacts by GRAIL and LADEE). The LRO instrument teams deliver data to the PDS every three months, data that includes raw, calibrated, and gridded/map products [3]. As of January, over 681TB has been archived. These higher-level data products include a number of resources that are useful for mission planners, in addition to planetary scientists. A focus of the mission has been on the South Pole, therefore a number of special products (e.g., illumination maps, high resolution topography, hydration maps) are available. Beyond the poles, high-resolution (~1-2 m spatial resolution) topographic products are available for select areas, as well as maps of rock abundance

  3. Sensitivity Analysis for Key Payloads and Orbital Parameters from the Next-Generation Moon-Gradiometer Satellite Gravity Program

    NASA Astrophysics Data System (ADS)

    Zheng, Wei; Hsu, Houtse; Zhong, Min; Yun, Meijuan

    2015-01-01

    This research principally focuses on the requirements analysis in terms of the next-generation Moon-Gradiometer satellite gravity program. Firstly, the new single and combined analytical error models applied to estimate the accuracy of the lunar gravitational field (e.g., geopotential coefficients, cumulative geoid height and cumulative gravity anomaly) influenced by the main error sources consisting of the satellite gravity gradient and satellite orbital position are created for the next-generation Moon-Gradiometer program. Secondly, the dependability of the new single and combined analytical error models is validated by the conformity of the cumulative lunar geoid height errors between the gravity gradient and orbital position. Finally, taking the current GRAIL (Gravity Recovery and Interior Laboratory) satellite gravity mission for reference, the sensitivity analysis for the next-generation Moon-Gradiometer gravity satellite system is comprehensively carried out. We propose to equip this with the new-type pivotal payloads of the lunar spacecraft comprising the electrostatic suspension gravity gradiometer and the drag-free control system and bring forward the matching measurement precision of the space-borne instruments (involving 3 × 10-12/s2 in the gravity gradient and 60 m in the orbital position) and the preferred orbital parameters (including an orbital altitude of 25 km, an observation period of 28 days and a sampling interval of 1 s) in the next-generation Moon-Gradiometer program.

  4. Utilization of Libration Points an Halo Orbits for Human Space Exploration in the Sun-Earth-Moon System an Beyond

    NASA Astrophysics Data System (ADS)

    Farquhar, R. W.; Belbruno, E. A.; Dunham, D. W.; Guo, Y.; McAdams, J.

    2002-01-01

    A plan to extend human space operations beyond low Earth orbit is described. Key elements of this plan include the utilization of orbits in the vicinity of collinear libration points in the Earth-Moon and Sun-Earth systems. The unique advantages of stationing robotic spacecraft in "halo orbits" and "Lissajous orbits" around these libration points have already been exploited by five scientific missions beginning with the International Sun-Earth Explorer-3 (ISEE-3) in 1978. Libration-point orbits also offer special advantages as staging nodes for human missions to the Moon, near-Earth asteroids, and Mars. For instance, an Interplanetary Transfer Vehicle (ITV) stationed at the Earth-Moon L2 point could be used to rendezvous with a near-Earth asteroid and then return to the libration point. The journey would begin with a small V maneuver at the libration point followed by a lunar swingby and a perigee V maneuver to enter the desired interplanetary transfer trajectory. Another propulsive maneuver at the asteroid would complete the rendezvous. A reverse procedure would be used to return the ITV to the libration point. With this technique, the ITV would save approximately 6 km/sec in V cost compared with an ITV stationed in low-Earth orbit. Of course, another vehicle would be needed to transfer fuel for the ITV as well as the flight crew and cargo from low-Earth orbit to the libration point. This additional vehicle, called a Deep-Space Shuttle (DSS), could also be used to transfer astronauts to and from lunar orbit, Earth-Moon and Sun-Earth libration points, and geosynchronous orbit. An overall strategy to develop the infrastructure needed for a libration-point staging capability is outlined in this paper. The use of the DSS to service large telescopes that are located in the vicinity of the Sun-Earth L2 point is also discussed.

  5. Recent extensional tectonics on the Moon revealed by the Lunar Reconnaissance Orbiter Camera

    NASA Astrophysics Data System (ADS)

    Watters, Thomas R.; Robinson, Mark S.; Banks, Maria E.; Tran, Thanh; Denevi, Brett W.

    2012-03-01

    Large-scale expressions of lunar tectonics--contractional wrinkle ridges and extensional rilles or graben--are directly related to stresses induced by mare basalt-filled basins. Basin-related extensional tectonic activity ceased about 3.6 Gyr ago, whereas contractional tectonics continued until about 1.2 Gyr ago. In the lunar highlands, relatively young contractional lobate scarps, less than 1 Gyr in age, were first identified in Apollo-era photographs. However, no evidence of extensional landforms was found beyond the influence of mare basalt-filled basins and floor-fractured craters. Here we identify previously undetected small-scale graben in the farside highlands and in the mare basalts in images from the Lunar Reconnaissance Orbiter Camera. Crosscut impact craters with diameters as small as about 10m, a lack of superposed craters, and graben depths as shallow as ~1m suggest these pristine-appearing graben are less than 50 Myr old. Thus, the young graben indicate recent extensional tectonic activity on the Moon where extensional stresses locally exceeded compressional stresses. We propose that these findings may be inconsistent with a totally molten early Moon, given that thermal history models for this scenario predict a high level of late-stage compressional stress that might be expected to completely suppress the formation of graben.

  6. On-orbit radiometric calibration over time and between spacecraft using the moon

    USGS Publications Warehouse

    Kieffer, H.H.; Stone, T.C.; Barnes, R.A.; Bender, S.; Eplee, R.E., Jr.; Mendenhall, J.; Ong, L.

    2002-01-01

    The Robotic Lunar Observatory (ROLO) project has developed a spectral irradiance model of the Moon that accounts for variations with lunar phase through the bright half of a month, lunar librations, and the location of an Earth-orbiting spacecraft. The methodology of comparing spacecraft observations of the Moon with this model has been developed to a set of standardized procedures so that comparisons can be readily made. In the cases where observations extend over several years (e.g., SeaWiFS), instrument response degradation has been determined with precision of about 0.1% per year. Because of the strong dependence of lunar irradiance on geometric angles, observations by two spacecraft cannot be directly compared unless acquired at the same time and location. Rather, the lunar irradiance based on each spacecraft instrument calibration can be compared with the lunar irradiance model. Even single observations by an instrument allow inter-comparison of its radiometric scale with other instruments participating in the lunar calibration program. Observations by SeaWiFS, ALI, Hyperion and MTI are compared here.

  7. The Lunar Reconnaissance Orbiter - Six Years of Science and Exploration at the Moon

    NASA Astrophysics Data System (ADS)

    Keller, John W.; Petro, Noah E.; McClanahan, Timothy P.; Vondrak, Richard R.

    2015-11-01

    The LRO mission, currently in an extended mission phase, is producing a remotely sensed dataset that is unrivaled in planetary science. With an ever-increasing baseline of measurements the LRO data has revealed the Moon’s surface and environment to be dynamic, with new craters and distal ejecta, variations in volatiles at and near the surface, a variable exosphere, and a surface that responds to variations in the flux of radiation from the Sun. Taken together the LRO dataset has significant value in forming how we understand airless bodies work in the Solar System and how planets evolve. We will discuss recent observations from the mission including, geologically recent volcanism, contemparay impacts, and polar volatiles.We will also discuss the mission's support of future exploration of the Moon. As initially conceived, one of the primary objectives for the Lunar Reconnaissance Orbiter (LRO) was to identify safe landing sites for future human and robotic exploration, and LRO mission remains capable of targeted high resolution observations to support the planning of future robotic missions to the Moon. The LRO team seeks to engage with mission planners to discuss LRO's enabaling capabilities.

  8. Experimental determination of salt partition coefficients between aqueous fluids, ice VI and ice VII: implication for the composition of the deep ocean and the geodynamics of large icy moons and water rich planets

    NASA Astrophysics Data System (ADS)

    Journaux, Baptiste; Daniel, Isabelle; Cardon, Hervé; Petitgirard, Sylvain; Perrillat, Jean-Philippe; Caracas, Razvan; Mezouar, Mohamed

    2015-04-01

    The potential habitability of extraterrestrial large aqueous reservoir in icy moons and exoplanets requires an input of nutrients and chemicals that may come from the rocky part of planetary body. Because of the presence of high pressure (HP) water ices (VI, VII, etc.) between the liquid ocean and the silicates, such interactions are considered to be limited in large icy moons, like Ganymede and Titan, and water rich exoplanets. In the case of salty-rich oceans, recent experimental and modeling works have shown that aqueous fluids can be stable at higher pressures [1, 2]. This can ultimately allow direct interaction with the rocky core of icy moons. This effect is nevertheless limited and for larger bodies such as water rich exoplanets with much higher pressures in their hydrosphere, HP ice should be present between the rocky core and a putative ocean. Salts are highly incompatible with low pressure ice Ih, but recent experimental work has shown that alkali metal and halogen salts are moderately incompatible with ice VII, that can incorporate up to several mol/kg of salts [3, 4, 5]. As far as we know, no similar study has been done on ice VI, a HP ice phase expected inside large icy moons. We present here the first experimental data on the partition coefficient of RbI salt between aqueous fluids, ice VI and ice VII using in-situ synchrotron X-Ray single crystal diffraction and X-Ray fluorescence mapping (ESRF - ID-27 beam line [6]). Our experiment enable us to observe a density inversion between ice VI and the salty fluid, and to measure the values of salt partition coefficients between the aqueous fluid and ice VI (strongly incompatible) and ice VII (moderately incompatible). Using the volumes determined with X-Ray diffraction, we were able to measure the density of salty ice VI and ice VII and determine that salty ice VI is lighter than pure H2O ice VI. These results are very relevant for the study of water rich planetary bodies interior because the partition

  9. Dynamical sequestration of the Moon-forming impactor in co-orbital resonance with Earth

    NASA Astrophysics Data System (ADS)

    Kortenkamp, Stephen J.; Hartmann, William K.

    2016-09-01

    Recent concerns about the giant impact hypothesis for the origin of the Moon, and an associated "isotope crisis" may be assuaged if the impactor was a local object that formed near Earth. We investigated a scenario that may meet this criterion, with protoplanets assumed to originate in 1:1 co-orbital resonance with Earth. Using N-body numerical simulations we explored the dynamical consequences of placing Mars-mass companions in various co-orbital configurations with a proto-Earth of 0.9 Earth-masses (M⊕). We modeled 162 different configurations, some with just the four terrestrial planets and others that included the four giant planets. In both the 4- and 8-planet models we found that a single Mars-mass companion typically remained a stable co-orbital of Earth for the entire 250 million year (Myr) duration of our simulations (59 of 68 unique simulations). In an effort to destabilize such a system we carried out an additional 94 simulations that included a second Mars-mass co-orbital companion. Even with two Mars-mass companions sharing Earth's orbit about two-thirds of these models (66) also remained stable for the entire 250 Myr duration of the simulations. Of the 28 2-companion models that eventually became unstable 24 impacts were observed between Earth and an escaping co-orbital companion. The average delay we observed for an impact of a Mars-mass companion with Earth was 102 Myr, and the longest delay was 221 Myr. In 40% of the 8-planet models that became unstable (10 out of 25) Earth collided with the nearly equal mass Venus to form a super-Earth (loosely defined here as mass ≥1.7 M⊕). These impacts were typically the final giant impact in the system and often occurred after Earth and/or Venus has accreted one or more of the other large objects. Several of the stable configurations involved unusual 3-planet hierarchical co-orbital systems.

  10. Identification of new orbits to enable future mission opportunities for the human exploration of the Martian moon Phobos

    NASA Astrophysics Data System (ADS)

    Zamaro, Mattia; Biggs, James D.

    2016-02-01

    One of the paramount stepping stones towards NASA's long-term goal of undertaking human missions to Mars is the exploration of the Martian moons. Since a precursor mission to Phobos would be easier than landing on Mars itself, NASA is targeting this moon for future exploration, and ESA has also announced Phootprint as a candidate Phobos sample-and-return mission. Orbital dynamics around small planetary satellites are particularly complex because many strong perturbations are involved, and the classical circular restricted three-body problem (R3BP) does not provide an accurate approximation to describe the system's dynamics. Phobos is a special case, since the combination of a small mass-ratio and length-scale means that the sphere-of-influence of the moon moves very close to its surface. Thus, an accurate nonlinear model of a spacecraft's motion in the vicinity of this moon must consider the additional perturbations due to the orbital eccentricity and the complete gravity field of Phobos, which is far from a spherical-shaped body, and it is incorporated into an elliptic R3BP using the gravity harmonics series-expansion (ER3BP-GH). In this paper, a showcase of various classes of non-keplerian orbits is identified and a number of potential mission applications in the Mars-Phobos system are proposed: these results could be exploited in upcoming unmanned missions targeting the exploration of this Martian moon. These applications include: low-thrust hovering and orbits around Phobos for close-range observations; the dynamical substitutes of periodic and quasi-periodic Libration Point Orbits in the ER3BP-GH to enable unique low-cost operations for space missions in the proximity of Phobos; their manifold structure for high-performance landing/take-off maneuvers to and from Phobos' surface and for transfers from and to Martian orbits; Quasi-Satellite Orbits for long-period station-keeping and maintenance. In particular, these orbits could exploit Phobos' occulting bulk

  11. S-NPP VIIRS on-orbit Band to Band Registration Estimation using the Moon

    NASA Astrophysics Data System (ADS)

    Choi, T.

    2015-12-01

    The Soumi National Polar-orbit Partnership (S-NPP) was successfully launched and has been operational since October 28, 2011, which carries the Visible Infrared Radiometer Suite (VIIRS) with among other instruments. Since VIIRS does not include on-board spatial calibrator such as Spectroradiometric Calibration Assembly (SRCA) on the predecessor sensor called MODerate resolution Imaging Spectroradiometer (MODIS), the on-orbit estimation of the spatial parameters needs to be measured independently. As a well-known radiometric target, the moon is utilized to estimate Band-to-Band (BBR) results as a part of spatial quality factors using the lifetime scheduled lunar collections. The reference band of the BBR is chosen to be the VIIRS band of Imaging band 1 (I1), because of its high signal-to-noise ratio, and high spatial sampling frequency compared to other moderate (M) bands. In this study, the conventional BBR calculation applied MODIS called weighted sum method is applied providing along-track and along-scan direction results. The BBR differences based on the reference band I1 results are very stable over the 3 years of VIIRS operation. The along-scan direction BBR results are mostly within ± 0.5 nominal Ground Sampling Distance (GSD) and the along-track direction BBR values are mostly between + 0.1 and -0.4 GSD. The final BBR results are available publically at the National Oceanic Atmospheric Agency (NOAA) Integrated Calibration Validation System (ICVS) webpage.

  12. Moonlet induced wakes in planetary rings: Analytical model including eccentric orbits of moon and ring particles

    NASA Astrophysics Data System (ADS)

    Seiß, M.; Spahn, F.; Schmidt, Jürgen

    2010-11-01

    Saturn's rings host two known moons, Pan and Daphnis, which are massive enough to clear circumferential gaps in the ring around their orbits. Both moons create wake patterns at the gap edges by gravitational deflection of the ring material (Cuzzi, J.N., Scargle, J.D. [1985]. Astrophys. J. 292, 276-290; Showalter, M.R., Cuzzi, J.N., Marouf, E.A., Esposito, L.W. [1986]. Icarus 66, 297-323). New Cassini observations revealed that these wavy edges deviate from the sinusoidal waveform, which one would expect from a theory that assumes a circular orbit of the perturbing moon and neglects particle interactions. Resonant perturbations of the edges by moons outside the ring system, as well as an eccentric orbit of the embedded moon, may partly explain this behavior (Porco, C.C., and 34 colleagues [2005]. Science 307, 1226-1236; Tiscareno, M.S., Burns, J.A., Hedman, M.M., Spitale, J.N., Porco, C.C., Murray, C.D., and the Cassini Imaging team [2005]. Bull. Am. Astron. Soc. 37, 767; Weiss, J.W., Porco, C.C., Tiscareno, M.S., Burns, J.A., Dones, L. [2005]. Bull. Am. Astron. Soc. 37, 767; Weiss, J.W., Porco, C.C., Tiscareno, M.S. [2009]. Astron. J. 138, 272-286). Here we present an extended non-collisional streamline model which accounts for both effects. We describe the resulting variations of the density structure and the modification of the nonlinearity parameter q. Furthermore, an estimate is given for the applicability of the model. We use the streamwire model introduced by Stewart (Stewart, G.R. [1991]. Icarus 94, 436-450) to plot the perturbed ring density at the gap edges. We apply our model to the Keeler gap edges undulated by Daphnis and to a faint ringlet in the Encke gap close to the orbit of Pan. The modulations of the latter ringlet, induced by the perturbations of Pan (Burns, J.A., Hedman, M.M., Tiscareno, M.S., Nicholson, P.D., Streetman, B.J., Colwell, J.E., Showalter, M.R., Murray, C.D., Cuzzi, J.N., Porco, C.C., and the Cassini ISS team [2005]. Bull. Am

  13. Formation and evolution of a circumterrestrial disk Constraints on the origin of the moon in geocentric orbit

    NASA Technical Reports Server (NTRS)

    Herbert, Floyd; Davis, Donald R.; Weidenschilling, Stuart J.

    1986-01-01

    A data base of about 25,000 numerically integrated trajectories of earth-encountering planetesimals is used to study the angular momentum problem of forming the moon out of material captured into a circumterrestrial disk from heliocentric orbits. Mass-orbital element distributions of incoming planetesimals are combined with this data base to calculate, as a function of distance from earth, the net geocentric specific angular momentum of disk-encountering material on heliocentric orbits. Results suggest that a permanent disk population is not possible.

  14. Exploring the Moon at High-Resolution: First Results From the Lunar Reconnaissance Orbiter Camera (LROC)

    NASA Astrophysics Data System (ADS)

    Robinson, Mark; Hiesinger, Harald; McEwen, Alfred; Jolliff, Brad; Thomas, Peter C.; Turtle, Elizabeth; Eliason, Eric; Malin, Mike; Ravine, A.; Bowman-Cisneros, Ernest

    The Lunar Reconnaissance Orbiter (LRO) spacecraft was launched on an Atlas V 401 rocket from the Cape Canaveral Air Force Station Launch Complex 41 on June 18, 2009. After spending four days in Earth-Moon transit, the spacecraft entered a three month commissioning phase in an elliptical 30×200 km orbit. On September 15, 2009, LRO began its planned one-year nominal mapping mission in a quasi-circular 50 km orbit. A multi-year extended mission in a fixed 30×200 km orbit is optional. The Lunar Reconnaissance Orbiter Camera (LROC) consists of a Wide Angle Camera (WAC) and two Narrow Angle Cameras (NACs). The WAC is a 7-color push-frame camera, which images the Moon at 100 and 400 m/pixel in the visible and UV, respectively, while the two NACs are monochrome narrow-angle linescan imagers with 0.5 m/pixel spatial resolution. LROC was specifically designed to address two of the primary LRO mission requirements and six other key science objectives, including 1) assessment of meter-and smaller-scale features in order to select safe sites for potential lunar landings near polar resources and elsewhere on the Moon; 2) acquire multi-temporal synoptic 100 m/pixel images of the poles during every orbit to unambiguously identify regions of permanent shadow and permanent or near permanent illumination; 3) meter-scale mapping of regions with permanent or near-permanent illumination of polar massifs; 4) repeat observations of potential landing sites and other regions to derive high resolution topography; 5) global multispectral observations in seven wavelengths to characterize lunar resources, particularly ilmenite; 6) a global 100-m/pixel basemap with incidence angles (60° -80° ) favorable for morphological interpretations; 7) sub-meter imaging of a variety of geologic units to characterize their physical properties, the variability of the regolith, and other key science questions; 8) meter-scale coverage overlapping with Apollo-era panoramic images (1-2 m/pixel) to document

  15. Exploring the Moon at High-Resolution: First Results From the Lunar Reconnaissance Orbiter Camera (LROC)

    NASA Astrophysics Data System (ADS)

    Robinson, Mark; Hiesinger, Harald; McEwen, Alfred; Jolliff, Brad; Thomas, Peter C.; Turtle, Elizabeth; Eliason, Eric; Malin, Mike; Ravine, A.; Bowman-Cisneros, Ernest

    The Lunar Reconnaissance Orbiter (LRO) spacecraft was launched on an Atlas V 401 rocket from the Cape Canaveral Air Force Station Launch Complex 41 on June 18, 2009. After spending four days in Earth-Moon transit, the spacecraft entered a three month commissioning phase in an elliptical 30×200 km orbit. On September 15, 2009, LRO began its planned one-year nominal mapping mission in a quasi-circular 50 km orbit. A multi-year extended mission in a fixed 30×200 km orbit is optional. The Lunar Reconnaissance Orbiter Camera (LROC) consists of a Wide Angle Camera (WAC) and two Narrow Angle Cameras (NACs). The WAC is a 7-color push-frame camera, which images the Moon at 100 and 400 m/pixel in the visible and UV, respectively, while the two NACs are monochrome narrow-angle linescan imagers with 0.5 m/pixel spatial resolution. LROC was specifically designed to address two of the primary LRO mission requirements and six other key science objectives, including 1) assessment of meter-and smaller-scale features in order to select safe sites for potential lunar landings near polar resources and elsewhere on the Moon; 2) acquire multi-temporal synoptic 100 m/pixel images of the poles during every orbit to unambiguously identify regions of permanent shadow and permanent or near permanent illumination; 3) meter-scale mapping of regions with permanent or near-permanent illumination of polar massifs; 4) repeat observations of potential landing sites and other regions to derive high resolution topography; 5) global multispectral observations in seven wavelengths to characterize lunar resources, particularly ilmenite; 6) a global 100-m/pixel basemap with incidence angles (60° -80° ) favorable for morphological interpretations; 7) sub-meter imaging of a variety of geologic units to characterize their physical properties, the variability of the regolith, and other key science questions; 8) meter-scale coverage overlapping with Apollo-era panoramic images (1-2 m/pixel) to document

  16. Toward a Unified View of the Moon's Polar Volatiles from the Lunar Reconnaissance Orbiter

    NASA Astrophysics Data System (ADS)

    Hayne, Paul

    2016-04-01

    Although the scientific basis for the possibility of water and other volatiles in the cold traps of the lunar polar regions was developed in the 1960's and '70's [1,2], only recently have the data become available to test the theories in detail. Furthermore, comparisons with other planetary bodies, particularly Mercury, have revealed surprising differences that may point to inconsistencies or holes in our understanding of the basic processes involving volatiles on airless bodies [3]. Addressing these gaps in understanding is critical to the future exploration of the Moon, for which water is an important scientific and engineering resource [4]. Launched in 2009, NASA's Lunar Reconnaissance Orbiter (LRO) has been acquiring data from lunar orbit for more than six years. All seven of the remote sensing instruments on the payload have now contributed significantly to advancing understanding of volatiles on the Moon. Here we present results from these investigations, and discuss attempts to synthesize the disparate information to create a self-consistent model for lunar volatiles. In addition to the LRO data, we must take into account results from earlier missions [5,6], ground-based telescopes [7], and sample analyses [8]. The results from these inter-comparisons show that water is likely available in useful quantities, but key additional measurements may be required to resolve remaining uncertainties. [1] Watson, K., Murray, B. C., & Brown, H. (1961), J. Geophys. Res., 66(9), 3033-3045. [2] Arnold, J. R. (1979), J. Geophys. Res. (1978-2012), 84(B10), 5659-5668. [3] Paige, D. A., Siegler, M. A., Harmon, J. K., Neumann, G. A., Mazarico, E. M., Smith, D. E., ... & Solomon, S. C. (2013), Science, 339(6117), 300-303. [4] Hayne, P. O., et al. (2014), Keck Inst. Space Studies Report. [5] Nozette, S., Lichtenberg, C. L., Spudis, P., Bonner, R., Ort, W., Malaret, E., ... & Shoemaker, E. M. (1996), Science, 274(5292), 1495-1498. [6] Pieters, C. M., Goswami, J. N., Clark, R. N

  17. Prospects in the orbital and rotational dynamics of the Moon with the advent of sub-centimeter lunar laser ranging

    NASA Astrophysics Data System (ADS)

    Kopeikin, S. M.; Pavlis, E.; Pavlis, D.; Brumberg, V. A.; Escapa, A.; Getino, J.; Gusev, A.; Müller, J.; Ni, W.-T.; Petrova, N.

    2008-10-01

    Lunar laser ranging (LLR) measurements are crucial for advanced exploration of the laws of fundamental gravitational physics and geophysics as well as for future human and robotic missions to the Moon. The corner-cube reflectors (CCR) currently on the Moon require no power and still work perfectly since their installation during the project Apollo era. Current LLR technology allows us to measure distances to the Moon with a precision approaching 1 mm. As NASA pursues the vision of taking humans back to the Moon, new, more precise laser ranging applications will be demanded, including continuous tracking from more sites on Earth, placing new CCR arrays on the Moon, and possibly installing other devices such as transponders, etc. for multiple scientific and technical purposes. Since this effort involves humans in space, then in all situations the accuracy, fidelity, and robustness of the measurements, their adequate interpretation, and any products based on them, are of utmost importance. Successful achievement of this goal strongly demands further significant improvement of the theoretical model of the orbital and rotational dynamics of the Earth-Moon system. This model should inevitably be based on the theory of general relativity, fully incorporate the relevant geophysical processes, lunar librations, tides, and should rely upon the most recent standards and recommendations of the IAU for data analysis. This paper discusses methods and problems in developing such a mathematical model. The model will take into account all the classical and relativistic effects in the orbital and rotational motion of the Moon and Earth at the sub-centimeter level. The model is supposed to be implemented as a part of the computer code underlying NASA Goddard's orbital analysis and geophysical parameter estimation package GEODYN and the ephemeris package PMOE 2003 of the Purple Mountain Observatory. The new model will allow us to navigate a spacecraft precisely to a location on the

  18. Radiometric calibration stability and inter-calibration of solar-band instruments in orbit using the moon

    USGS Publications Warehouse

    Stone, T.C.

    2008-01-01

    With the increased emphasis on monitoring the Earth's climate from space, more stringent calibration requirements are being placed on the data products from remote sensing satellite instruments. Among these are stability over decade-length time scales and consistency across sensors and platforms. For radiometer instruments in the solar reflectance wavelength range (visible to shortwave infrared), maintaining calibration on orbit is difficult due to the lack of absolute radiometric standards suitable for flight use. The Moon presents a luminous source that can be viewed by all instruments in Earth orbit. Considered as a solar diffuser, the lunar surface is exceedingly stable. The chief difficulty with using the Moon is the strong variations in the Moon's brightness with illumination and viewing geometry. This mandates the use of a photometric model to compare lunar observations, either over time by the same instrument or between instruments. The U.S. Geological Survey in Flagstaff, Arizona, under NASA sponsorship, has developed a model for the lunar spectral irradiance that explicitly accounts for the effects of phase, the lunar librations, and the lunar surface reflectance properties. The model predicts variations in the Moon's brightness with precision ???1% over a continuous phase range from eclipse to the quarter lunar phases. Given a time series of Moon observations taken by an instrument, the geometric prediction capability of the lunar irradiance model enables sensor calibration stability with sub-percent per year precision. Cross-calibration of instruments with similar passbands can be achieved with precision comparable to the model precision. Although the Moon observations used for intercomparison can be widely separated in phase angle and/or time, SeaWiFS and MODIS have acquired lunar views closely spaced in time. These data provide an example to assess inter-calibration biases between these two instruments.

  19. Analysis of Periodic Orbits about the Triangular Solutions of the Restricted Sum-Jupiter and Earth-Moon Problem

    NASA Astrophysics Data System (ADS)

    Park, Sang-Young; Jo, Jung-Hyun; Lee, Byoung-Sun; Choi, Kyu-Hong

    1988-12-01

    Using the numerical solution in the plane restricted problem of three bodies, about 490 periodic orbits are computed numerically around the L5 of Sun-Jupiter and about 1600 periodic orbits also be done around the L5 of Earth-Moon system. As period increase, the energy and the shape of periodic orbits increase around the L5 of Sun-Jupiter system. But, in Earth-Moon system, the complex shapes and dents appear around the L5 and periodic orbits intersect one another in the place where dents are shown. And there is a region that three different periodic orbits exist with the same period in this region. The regions can exist around the L5 of Sun-Jupiter system where periodic orbit can be unstable by perturbation of other force besides the gravitational force of Jupiter. These regions which is close to L5 are a ¡­ 5.29 AU. The Trojan asteroids that have a small eccentricity and inclination can not exist in this region.

  20. MIDAS: Advanced Remote Sensing for the Exploration of Icy Satellites

    NASA Astrophysics Data System (ADS)

    Rieboldt, S. E.; Wong, M. H.; Adamkovics, M.; Delory, G. T.; de Pater, I.; Manga, M.; Lipps, J. H.; Dalton, J. B.; Pitman, J.; Kendrick, R. L.

    2005-12-01

    The Multiple Instrument Distributed Aperture Sensor (MIDAS) is a diffraction-limited, wide-field imaging spectrometer that utilizes distributed apertures and optical interferometer techniques to achieve simultaneous high spatial and spectral resolution. Here we describe the results of a science and technical feasibility study of MIDAS prototypes funded under the NASA High Capability Instrument Concepts and Technology (HCICT) program as a potential science payload for missions to the outer planets and their icy satellites. The high spatial resolution capabilities of MIDAS combined with nm spectral resolution will greatly advance our understanding of icy satellite surface composition in terms of minerals, organics, volatiles, and their mixtures. From 100 km mapping orbits, cm-scale imagery from MIDAS could revolutionize our understanding of the geology, dynamics, and history of icy moon surfaces. From higher orbits, MIDAS can engage in global, high resolution imaging spectroscopy with m-scale resolution for months at a time. Beyond traditional remote sensing, MIDAS is well suited to active techniques, including remote Raman, Fluorescence, and IR illumination investigations, in order to resolve surface composition and explore otherwise dim regions.

  1. Icy Satellite Science Today and in Cassini's Final Three Years

    NASA Astrophysics Data System (ADS)

    Buratti, B. J.

    2014-12-01

    The Cassini Mission has turned our view of Saturn's icy moons from scientific sketches to fully realized worlds. Among the major discoveries are: Activity on Enceladus and associated plumes that originate in small hot spots on its south pole and that appear to be modulated by tidal forces; a liquid subsurface water ocean on Enceladus that is a habitable environment; several new moons; debris rings associated with moons; a unique equatorial ridge on Iapetus; the identity of new constituents on the moons including carbon dioxide ice on most of them and polycyclic aromatic hydrocarbons (PAHs)on Iapetus; differentiated or partially differentiated interiors; nano-iron on the surfaces of the moons and in the rings; volatile segregation on Iapetus and Hyperion; and a bewildering array of geologic processes on the small moons. But our new view of these icy worlds has spawned new questions. Among these unanswered questions are: How variable are the plumes? Have any other moons had activity similar to that on Enceladus and did it continue up to the recent past? How much dust do the moons contribute to the region around Saturn? What caused the ridge on Iapetus? What are the interiors of the moons like? How differentiated and compensated are they? Five additional targeted flybys, two of Dione and three of Enceladus, have been designed to answer these questions and will be implemented during the remainder of the Solstice Mission. The Dione flybys both include gravity passes to determine its state of differentiation. One of the flybys is optimized to measure the fields and particle environment around Dione. One of the two remote-sensing flybys of Enceladus will scrutinize the south polar region to further understand the size, temperature, and variability of the emitting areas, while the other will observe the north pole to determine why it is so different from the south. The third Enceladus flyby involves an unprecedented pass less than 50 km above the surface into the midst of

  2. The H2O and O2 exospheres of Ganymede: The result of a complex interaction between the jovian magnetospheric ions and the icy moon

    NASA Astrophysics Data System (ADS)

    Plainaki, Christina; Milillo, Anna; Massetti, Stefano; Mura, Alessandro; Jia, Xianzhe; Orsini, Stefano; Mangano, Valeria; De Angelis, Elisabetta; Rispoli, Rosanna

    2015-01-01

    The H2O and O2 exospheres of Jupiter's moon Ganymede are simulated through the application of a 3D Monte Carlo modeling technique that takes into consideration the combined effect on the exosphere generation of the main surface release processes (i.e. sputtering, sublimation and radiolysis) and the surface precipitation of the energetic ions of Jupiter's magnetosphere. In order to model the magnetospheric ion precipitation to Ganymede's surface, we used as an input the electric and magnetic fields from the global MHD model of Ganymede's magnetosphere (Jia, X., Walker, R.J., Kivelson, M.G., Khurana, K.K., Linker, J.A. [2009]. J. Geophys. Res. 114, A09209). The exospheric model described in this paper is based on EGEON, a single-particle Monte Carlo model already applied for a Galilean satellite (Plainaki, C., Milillo, A., Mura, A., Orsini, S., Cassidy, T. [2010]. Icarus 210, 385-395; Plainaki, C., Milillo, A., Mura, A., Orsini, S., Massetti, S., Cassidy, T. [2012]. Icarus 218 (2), 956-966; Plainaki, C., Milillo, A., Mura, A., Orsini, S., Saur [2013]. Planet. Space Sci. 88, 42-52); nevertheless, significant modifications have been implemented in the current work in order to include the effect on the exosphere generation of the ion precipitation geometry determined strongly by Ganymede's intrinsic magnetic field (Kivelson, M.G. et al. [1996]. Nature 384, 537-541). The current simulation refers to a specific configuration between Jupiter, Ganymede and the Sun in which the Galilean moon is located close to the center of Jupiter's Plasma Sheet (JPS) with its leading hemisphere illuminated. Our results are summarized as follows: (a) at small altitudes above the moon's subsolar point the main contribution to the neutral environment comes from sublimated H2O; (b) plasma precipitation occurs in a region related to the open-closed magnetic field lines boundary and its extent depends on the assumption used to mimic the plasma mirroring in Jupiter's magnetosphere; (c) the

  3. Larger Icy Satellites

    NASA Astrophysics Data System (ADS)

    Vance, Steven; Buratti, B. J.; Hansen, C.; Hurford, T.; McKinnon, W. B.; Pappalardo, R. T.; Turtle, E. P.

    2009-09-01

    Outer planets exploration in the past three decades has revealed a diverse host of large icy bodies undergoing a myriad of geological and chemical processes remarkably similar yet alien to those occurring on Earth. The most active of these, including the Galilean satellites and Saturn's moons Enceladus and Titan, are obvious targets for future robotic exploration. The broader host of satellites larger than 100 km should also figure into NASA's goals, owing to their abundance and insights they offer into past and present geological processes, Solar System formation and planetary evolution. Included in this class are the enigmatic objects Dione, with its smooth planes and fractured regions; Mimas with its giant crater Herschel; Iapetus, which has an odd shape and a mysterious equatorial ridge; Miranda, which has been subjected to drastic geologic reconfiguration; and Triton, with its geyser-like plumes. Many bodies in this class are of sufficient size and density to have hosted internal liquid water oceans in their early history, or even in the present epoch, making them targets of astrobiological interest. We discuss the importance of larger icy satellites to NASA's objectives, their importance for understanding, geology, chemistry and dynamics in the Solar System, and observational and experimental challenges that need to be addressed in the next decade.

  4. The Moon Mineralogy Mapper (M3) imaging spectrometer for lunar science: Instrument description, calibration, on-orbit measurements, science data calibration and on-orbit validation

    USGS Publications Warehouse

    Green, R.O.; Pieters, C.; Mouroulis, P.; Eastwood, M.; Boardman, J.; Glavich, T.; Isaacson, P.; Annadurai, M.; Besse, S.; Barr, D.; Buratti, B.; Cate, D.; Chatterjee, A.; Clark, R.; Cheek, L.; Combe, J.; Dhingra, D.; Essandoh, V.; Geier, S.; Goswami, J.N.; Green, R.; Haemmerle, V.; Head, J.; Hovland, L.; Hyman, S.; Klima, R.; Koch, T.; Kramer, G.; Kumar, A.S.K.; Lee, Kenneth; Lundeen, S.; Malaret, E.; McCord, T.; McLaughlin, S.; Mustard, J.; Nettles, J.; Petro, N.; Plourde, K.; Racho, C.; Rodriquez, J.; Runyon, C.; Sellar, G.; Smith, C.; Sobel, H.; Staid, M.; Sunshine, J.; Taylor, L.; Thaisen, K.; Tompkins, S.; Tseng, H.; Vane, G.; Varanasi, P.; White, M.; Wilson, D.

    2011-01-01

    The NASA Discovery Moon Mineralogy Mapper imaging spectrometer was selected to pursue a wide range of science objectives requiring measurement of composition at fine spatial scales over the full lunar surface. To pursue these objectives, a broad spectral range imaging spectrometer with high uniformity and high signal-to-noise ratio capable of measuring compositionally diagnostic spectral absorption features from a wide variety of known and possible lunar materials was required. For this purpose the Moon Mineralogy Mapper imaging spectrometer was designed and developed that measures the spectral range from 430 to 3000 nm with 10 nm spectral sampling through a 24 degree field of view with 0.7 milliradian spatial sampling. The instrument has a signal-to-noise ratio of greater than 400 for the specified equatorial reference radiance and greater than 100 for the polar reference radiance. The spectral cross-track uniformity is >90% and spectral instantaneous field-of-view uniformity is >90%. The Moon Mineralogy Mapper was launched on Chandrayaan-1 on the 22nd of October. On the 18th of November 2008 the Moon Mineralogy Mapper was turned on and collected a first light data set within 24 h. During this early checkout period and throughout the mission the spacecraft thermal environment and orbital parameters varied more than expected and placed operational and data quality constraints on the measurements. On the 29th of August 2009, spacecraft communication was lost. Over the course of the flight mission 1542 downlinked data sets were acquired that provide coverage of more than 95% of the lunar surface. An end-to-end science data calibration system was developed and all measurements have been passed through this system and delivered to the Planetary Data System (PDS.NASA.GOV). An extensive effort has been undertaken by the science team to validate the Moon Mineralogy Mapper science measurements in the context of the mission objectives. A focused spectral, radiometric

  5. Station-keeping of real Earth-Moon libration point orbits using discrete-time sliding mode control

    NASA Astrophysics Data System (ADS)

    Lian, Yijun; Gómez, Gerard; Masdemont, Josep J.; Tang, Guojian

    2014-10-01

    In this work, station-keeping of real Earth-Moon libration point orbits is studied using discrete-time sliding mode control (DSMC). For comparison, a discrete linear quadratic regulator (DLQR) controller is also considered. The libration orbits are termed “real” in the sense that they are obtained in a complete Solar System model, taking into account all the gravitational forces of the planets, the Moon, and the Sun. This is a key point for any station-keeping study, that the use of far from real orbits as nominal ones increases unnecessarily the station-keeping cost. The resulting controlled system, linearised with respect to some nominal orbit, takes a discrete-time form suitable for applying impulsive maneuvers. The DSMC controller is designed by the reaching law with the parameters chosen in an adaptive way. A method for designing the sliding surface is proposed. In order to assess and compare the performance of the two controllers, simulations are done for six libration point orbits around the L2 point (three halo orbits and three Lissajous ones) during a time span of 10 years. Several practical constraints are also considered in the simulations. Extensive Monte Carlo results show that the proposed DSMC approach is able to maintain the spacecraft within a close vicinity of the nominal orbits with a maneuver cost less than 2 m/s per year, and it outperforms the DLQR approach in terms of the position controllability. Some comparison with previous results obtained by other authors with different procedures is also given.

  6. Experiment LEND of the NASA Lunar Reconnaissance Orbiter for high-resolution mapping of neutron emission of the Moon.

    PubMed

    Mitrofanov, I G; Sanin, A B; Golovin, D V; Litvak, M L; Konovalov, A A; Kozyrev, A S; Malakhov, A V; Mokrousov, M I; Tretyakov, V I; Troshin, V S; Uvarov, V N; Varenikov, A B; Vostrukhin, A A; Shevchenko, V V; Shvetsov, V N; Krylov, A R; Timoshenko, G N; Bobrovnitsky, Y I; Tomilina, T M; Grebennikov, A S; Kazakov, L L; Sagdeev, R Z; Milikh, G N; Bartels, A; Chin, G; Floyd, S; Garvin, J; Keller, J; McClanahan, T; Trombka, J; Boynton, W; Harshman, K; Starr, R; Evans, L

    2008-08-01

    The scientific objectives of neutron mapping of the Moon are presented as 3 investigation tasks of NASA's Lunar Reconnaissance Orbiter mission. Two tasks focus on mapping hydrogen content over the entire Moon and on testing the presence of water-ice deposits at the bottom of permanently shadowed craters at the lunar poles. The third task corresponds to the determination of neutron contribution to the total radiation dose at an altitude of 50 km above the Moon. We show that the Lunar Exploration Neutron Detector (LEND) will be capable of carrying out all 3 investigations. The design concept of LEND is presented together with results of numerical simulations of the instrument's sensitivity for hydrogen detection. The sensitivity of LEND is shown to be characterized by a hydrogen detection limit of about 100 ppm for a polar reference area with a radius of 5 km. If the presence of ice deposits in polar "cold traps" is confirmed, a unique record of many millions of years of lunar history would be obtained, by which the history of lunar impacts could be discerned from the layers of water ice and dust. Future applications of a LEND-type instrument for Mars orbital observations are also discussed. PMID:18844457

  7. NASA's Planned Return to the Moon: Global Access and Anytime Return Requirement Implications on the Lunar Orbit Insertion Burns

    NASA Technical Reports Server (NTRS)

    Garn, Michelle; Qu, Min; Chrone, Jonathan; Su, Philip; Karlgaard, Chris

    2008-01-01

    Lunar orbit insertion LOI is a critical maneuver for any mission going to the Moon. Optimizing the geometry of this maneuver is crucial to the success of the architecture designed to return humans to the Moon. LOI burns necessary to meet current NASA Exploration Constellation architecture requirements for the lunar sortie missions are driven mainly by the requirement for global access and "anytime" return from the lunar surface. This paper begins by describing the Earth-Moon geometry which creates the worst case (delta)V for both the LOI and the translunar injection (TLI) maneuvers over the full metonic cycle. The trajectory which optimizes the overall (delta)V performance of the mission is identified, trade studies results covering the entire lunar globe are mapped onto the contour plots, and the effects of loitering in low lunar orbit as a means of reducing the insertion (delta)V are described. Finally, the lighting conditions on the lunar surface are combined with the LOI and TLI analyses to identify geometries with ideal lighting conditions at sites of interest which minimize the mission (delta)V.

  8. Investigating at the Moon With new Eyes: The Lunar Reconnaissance Orbiter Mission Camera (LROC)

    NASA Astrophysics Data System (ADS)

    Hiesinger, H.; Robinson, M. S.; McEwen, A. S.; Turtle, E. P.; Eliason, E. M.; Jolliff, B. L.; Malin, M. C.; Thomas, P. C.

    The Lunar Reconnaissance Orbiter Mission Camera (LROC) H. Hiesinger (1,2), M.S. Robinson (3), A.S. McEwen (4), E.P. Turtle (4), E.M. Eliason (4), B.L. Jolliff (5), M.C. Malin (6), and P.C. Thomas (7) (1) Brown Univ., Dept. of Geological Sciences, Providence RI 02912, Harald_Hiesinger@brown.edu, (2) Westfaelische Wilhelms-University, (3) Northwestern Univ., (4) LPL, Univ. of Arizona, (5) Washington Univ., (6) Malin Space Science Systems, (7) Cornell Univ. The Lunar Reconnaissance Orbiter (LRO) mission is scheduled for launch in October 2008 as a first step to return humans to the Moon by 2018. The main goals of the Lunar Reconnaissance Orbiter Camera (LROC) are to: 1) assess meter and smaller- scale features for safety analyses for potential lunar landing sites near polar resources, and elsewhere on the Moon; and 2) acquire multi-temporal images of the poles to characterize the polar illumination environment (100 m scale), identifying regions of permanent shadow and permanent or near permanent illumination over a full lunar year. In addition, LROC will return six high-value datasets such as 1) meter-scale maps of regions of permanent or near permanent illumination of polar massifs; 2) high resolution topography through stereogrammetric and photometric stereo analyses for potential landing sites; 3) a global multispectral map in 7 wavelengths (300-680 nm) to characterize lunar resources, in particular ilmenite; 4) a global 100-m/pixel basemap with incidence angles (60-80 degree) favorable for morphologic interpretations; 5) images of a variety of geologic units at sub-meter resolution to investigate physical properties and regolith variability; and 6) meter-scale coverage overlapping with Apollo Panoramic images (1-2 m/pixel) to document the number of small impacts since 1971-1972, to estimate hazards for future surface operations. LROC consists of two narrow-angle cameras (NACs) which will provide 0.5-m scale panchromatic images over a 5-km swath, a wide

  9. The icy Jovian satellites after the Galileo mission

    NASA Astrophysics Data System (ADS)

    Greenberg, Richard

    2010-03-01

    The icy satellites of Jupiter, Callisto, Ganymede, Europa and Amalthea have diverse and remarkable characteristics. Their initial compositions were determined by conditions in the circum-Jovian nebula, just as the planets' initial properties were governed by their formation within the circumsolar nebula. The satellites subsequently evolved under the complex interplay of orbital and geophysical processes, especially the effects of orbital resonances, tides, internal differentiation and heat. The history and character of the satellites can be inferred from consideration of the formation of planets and the satellites, from studies of their plausible orbital evolution, from measurements of geophysical properties, especially gravitational and magnetic fields, from observations of the compositions and geological structure of their surfaces and from theoretical modeling of the processes that connect these lines of evidence. The three large icy satellites probably contain significant liquid water: Europa has a deep liquid water ocean under a thin surface layer of ice; Ganymede and Callisto likely have relatively thin liquid water layers deep below their surfaces. Models of formation are challenged by the surprising properties of the outermost and innermost of the group: Callisto is partially differentiated, with rock and ice mixed through much of its interior; and tiny Amalthea also appears to be largely composed of ice. Each of the four moons is fascinating in its own right, and the ensemble provides a powerful set of constraints on the processes that led to their formation and evolution.

  10. The Lunar Scout Program: An international program to survey the Moon from orbit for geochemistry, mineralogy, imagery, geodesy, and gravity

    NASA Technical Reports Server (NTRS)

    Morrison, Donald A. (Editor)

    1994-01-01

    The Lunar Scout Program was one of a series of attempts by NASA to develop and fly an orbiting mission to the moon to collect geochemical, geological, and gravity data. Predecessors included the Lunar Observer, the Lunar Geochemical Orbiter, and the Lunar Polar Orbiter - missions studied under the auspices of the Office of Space Science. The Lunar Scout Program, however, was an initiative of the Office of Exploration. It was begun in late 1991 and was transferred to the Office of Space Science after the Office of Exploration was disbanded in 1993. Most of the work was done by a small group of civil servants at the Johnson Space Center; other groups also responsible for mission planning included personnel from the Charles Stark Draper Laboratories, the Lawrence Livermore National Laboratory, Boeing, and Martin Marietta. The Lunar Scout Program failed to achieve new start funding in FY 93 and FY 94 as a result of budget downturns, the de-emphasis of the Space Exploration Initiative, and the fact that lunar science did not rate as high a priority as other planned planetary missions, and was cancelled. The work done on the Lunar Scout Program and other lunar orbiter studies, however, represents assets that will be useful in developing new approaches to lunar orbit science.

  11. The Lunar Scout Program: an international program to survey the Moon from orbit for geochemistry, mineralogy, imagery, geodesy, and gravity

    NASA Astrophysics Data System (ADS)

    Morrison, Donald A.

    1994-04-01

    The Lunar Scout Program was one of a series of attempts by NASA to develop and fly an orbiting mission to the moon to collect geochemical, geological, and gravity data. Predecessors included the Lunar Observer, the Lunar Geochemical Orbiter, and the Lunar Polar Orbiter - missions studied under the auspices of the Office of Space Science. The Lunar Scout Program, however, was an initiative of the Office of Exploration. It was begun in late 1991 and was transferred to the Office of Space Science after the Office of Exploration was disbanded in 1993. Most of the work was done by a small group of civil servants at the Johnson Space Center; other groups also responsible for mission planning included personnel from the Charles Stark Draper Laboratories, the Lawrence Livermore National Laboratory, Boeing, and Martin Marietta. The Lunar Scout Program failed to achieve new start funding in FY 93 and FY 94 as a result of budget downturns, the de-emphasis of the Space Exploration Initiative, and the fact that lunar science did not rate as high a priority as other planned planetary missions, and was cancelled. The work done on the Lunar Scout Program and other lunar orbiter studies, however, represents assets that will be useful in developing new approaches to lunar orbit science.

  12. Correlation of dark mantle deposits with high Mg/Al ratios. [from orbital X-ray fluorescence experiment on moon

    NASA Technical Reports Server (NTRS)

    Schonfeld, E.; Bielefeld, M. J.

    1978-01-01

    The Mg/Al concentration ratios from the orbital fluorescence X-ray experiment were used to characterize dark mantle deposits on the moon. The areas studied included the regions of Sulpicius Gallus, Taurus-Littrow, Hadley Rille, Mare Crisium (craters Picard and Pierce), and NE Mare Fecunditatis. In all these cases these deposits exhibit high Mg/Al ratios which suggest the presence of orange, black, and green pyroclastic glasses. The highest concentration of glasses was inferred in the Sulpicius Gallus Formation at about 35%. The depth of the initial pyroclastic deposits was estimated at 3 to 4 meters. Central Mare Serenitatis exhibits high Mg/Al values but does not possess dark mantle deposits. Orbital Al and Mg/Al data for this region is similar to the very low titanium mare basalts.

  13. The effects of laterally varying icy shell structure on the tidal response of Europa and Ganymede

    NASA Astrophysics Data System (ADS)

    Wahr, J. M.; A, G.; Zhong, S.

    2013-12-01

    One of the long-sought objectives of an icy moon orbiter or fly-by mission, has been to use tidal observations to help determine the existence of a liquid ocean and characteristics of the overlying icy shell. The radio science component of such a mission could be used to estimate the tidal potential Love number k2 for gravity. And if there is an on-board laser altimeter, it could be used to determine the radial displacement Love number h2. Knowledge of either of those Love numbers could provide information on the presence of an ocean beneath the icy outer shell, and the two Love numbers could be combined to place constraints on the thickness of the icy shell. Though if a subsurface ocean exists, complications could conceivably arise if the icy outer shell has significant lateral variations in elastic thickness or shear modulus, or if the ocean is not global in extent so that the icy shell is grounded in places but floating in others. In these cases, the tidal deformation pattern would not be represented as the sum of degree 2 harmonics, and so the results could not be characterized in terms of a single Love number. In this study, by solving a set of tidal loading problems with laterally variable icy shell structures (for which the existence of an ocean layer is assumed), we investigate how those structures might complicate the interpretation of the tide measurements, and we discuss how to extract information regarding the interior structure of Ganymede and Europa from measurements of their tidal response.

  14. Optimization of Return Trajectories for Orbital Transfer Vehicle between Earth and Moon

    NASA Technical Reports Server (NTRS)

    Funase, Ryu; Tsuda, Yuichi; Kawaguchi, Jun'ichiro

    2007-01-01

    In this paper, optimum trajectories in Earth Transfer Orbit (ETO) for a lunar transportation system are proposed. This paper aims at improving the payload ratio of the reusable orbital transfer vehicle (OTV), which transports the payload from Low Earth Orbit (LEO) to Lunar Low Orbit (LLO) and returns to LEO. In ETO, we discuss ballistic flight using chemical propulsion, multi-impulse flight using electrical propulsion, and aero-assisted flight using aero-brake. The feasibility of the OTV is considered.

  15. The interaction between Saturn's moons and their plasma environments

    NASA Astrophysics Data System (ADS)

    Simon, Sven; Roussos, Elias; Paty, Carol S.

    2015-11-01

    Since the arrival of the Cassini spacecraft at Saturn in July 2004, newly collected plasma and magnetic field data have greatly expanded our knowledge on the interaction between the giant planet's multifaceted family of moons and its magnetospheric environment. Cassini has already accomplished more than 200 orbits around Saturn, encompassing 111 flybys of the giant planet's largest moon Titan and 20 encounters of Enceladus. This small icy moon had been identified as the major source of magnetospheric plasma and neutral particles during the first year of Cassini's tour in the Saturnian system. In addition, the spacecraft has paid visits to several other icy satellites in the inner and middle magnetosphere: Rhea, Dione and Tethys. Depending on the ambient magnetospheric flow parameters as well as the properties of its atmosphere/ionosphere and surface, each of these moons generates a characteristic and unique set of perturbation signatures in the magnetospheric plasma incident upon it. Therefore, observations made during close flybys of Saturn's moons by the Cassini plasma and magnetic field detectors contain valuable diagnostic information on the properties of the moons' atmospheres, surfaces and even their interiors. However, the spacecraft can measure these plasma and magnetic field perturbations only along its trajectory, whereas the interaction between the moons and their plasma environments constitutes a complex three-dimensional process. Therefore, sophisticated models are required in order to place the data collected along Cassini's flyby trajectories within the context of the full three-dimensional moon-plasma interaction scenarios. In this review, we combine observations from the Cassini mission with sophisticated modeling results to draw a comprehensive picture of the interaction between Saturn's largest moons and their highly dynamic plasma environments.

  16. Determining parameters of Moon's orbital and rotational motion from LLR observations using GRAIL and IERS-recommended models

    NASA Astrophysics Data System (ADS)

    Pavlov, Dmitry A.; Williams, James G.; Suvorkin, Vladimir V.

    2016-07-01

    The aim of this work is to combine the model of orbital and rotational motion of the Moon developed for DE430 with up-to-date astronomical, geodynamical, and geo- and selenophysical models. The parameters of the orbit and physical libration are determined in this work from lunar laser ranging (LLR) observations made at different observatories in 1970-2013. Parameters of other models are taken from solutions that were obtained independently from LLR. A new implementation of the DE430 lunar model, including the liquid core equations, was done within the EPM ephemeris. The postfit residuals of LLR observations make evident that the terrestrial models and solutions recommended by the IERS Conventions are compatible with the lunar theory. That includes: EGM2008 gravitational potential with conventional corrections and variations from solid and ocean tides; displacement of stations due to solid and ocean loading tides; and precession-nutation model. Usage of these models in the solution for LLR observations has allowed us to reduce the number of parameters to be fit. The fixed model of tidal variations of the geopotential has resulted in a lesser value of Moon's extra eccentricity rate, as compared to the original DE430 model with two fit parameters. A mixed model of lunar gravitational potential was used, with some coefficients determined from LLR observations, and other taken from the GL660b solution obtained from the GRAIL spacecraft mission. Solutions obtain accurate positions for the ranging stations and the five retroreflectors. Station motion is derived for sites with long data spans. Dissipation is detected at the lunar fluid core-solid mantle boundary demonstrating that a fluid core is present. Tidal dissipation is strong at both Earth and Moon. Consequently, the lunar semimajor axis is expanding by 38.20 mm/yr, the tidal acceleration in mean longitude is -25.90 {{}^' ' }}/cy^2 , and the eccentricity is increasing by 1.48× 10^{-11} each year.

  17. The steepest slopes on the Moon from Lunar Orbiter Laser Altimeter (LOLA) Data: Spatial Distribution and Correlation with Geologic Features

    NASA Astrophysics Data System (ADS)

    Kreslavsky, Mikhail A.; Head, James W.

    2016-07-01

    We calculated topographic gradients over the surface of the Moon at a 25 m baseline using data obtained by the Lunar Orbiter Laser Altimeter (LOLA) instrument onboard the Lunar Reconnaissance Orbiter (LRO) spacecraft. The relative spatial distribution of steep slopes can be reliably obtained, although some technical characteristics of the LOLA dataset preclude statistical studies of slope orientation. The derived slope-frequency distribution revealed a steep rollover for slopes close to the angle of repose. Slopes significantly steeper than the angle of repose are almost absent on the Moon due to (1) the general absence of cohesion/strength of the fractured and fragmented megaregolith of the lunar highlands, and (2) the absence of geological processes producing steep-slopes in the recent geological past. The majority of slopes steeper than 32°-35° are associated with relatively young large impact craters. We demonstrate that these impact craters progressively lose their steepest slopes. We also found that features of Early Imbrian and older ages have almost no slopes steeper than 35°. We interpret this to be due to removal of all steep slopes by the latest basin-forming impact (Orientale), probably by global seismic shaking. The global spatial distribution of the steepest slopes correlates moderately well with the predicted spatial distribution of impact rate; however, a significant paucity of steep slopes in the southern farside remains unexplained.

  18. Icy Tendrils from Enceladus

    NASA Astrophysics Data System (ADS)

    Mitchell, C. J.; Porco, C.; Weiss, J. W.

    2015-12-01

    We extend our previous work (Mitchell et al., 2015) in simulating thelarge-scale, sinuous structures, dubbed 'tendrils', observed inCassini ISS images of the E ring near Enceladus. We follow thetrajectories of particles launched from the geyser sources locatedacross the moon's south polar terrain (Porco et al., 2014), assumingthe velocity distribution of Ingersoll and Ewald, (2011), andincluding forces due to the gravity of Saturn and Enceladus, as wellas Saturn's magnetic and electric fields. Charging currents arisingfrom interactions with magnetospheric plasma and Solar UV radiationare also included. The simulations are used to produce syntheticimages which we compare to Cassini ISS tendril images taken in 2006and 2013. We found that specific subsets of geysers appear to be thesources of identifiable tendril features present in the images.However, there remained features not captured by our initialsimulations: a shift in longitude for the brightest part of thetendrils and two features which only appear in some images.In this initial work, we neglected Enceladus' orbital eccentricity aswell as the periodicity and phase of the variability in geyseringactivity recently discovered and attributed to a ~5-hour delay in thediurnally variable tidal stresses at the surface (Nimmo et al. 2014).And we made no attempt to do a photometric determination of the masslost from the moon into orbit around Saturn.We will report on our progress in rectifying these inadequacies. Wewill present the result of including Enceladus's orbital eccentricity,as well as a diurnally variable particle flux out of each geyser, inaccord with the observed plume variability. Eventually, we will usethe absolute brightness of the tendrils, together with a photometricmodel and information on the particle size distribution from our work,and the work of other Cassini teams on E ring particles, to arrive atthe amount of mass leaving the moon and entering Saturn orbit.Mitchell et al., 2015, AJ, 149, 156

  19. Space Weathering on Icy Satellites in the Outer Solar System

    NASA Technical Reports Server (NTRS)

    Clark, R. N.; Perlman, Z.; Pearson, N.; Cruikshank, D. P.

    2014-01-01

    Space weathering produces well-known optical effects in silicate minerals in the inner Solar System, for example, on the Moon. Space weathering from solar wind and UV (ultraviolet radiation) is expected to be significantly weaker in the outer Solar System simply because intensities are low. However, cosmic rays and micrometeoroid bombardment would be similar to first order. That, combined with the much higher volatility of icy surfaces means there is the potential for space weathering on icy outer Solar System surfaces to show optical effects. The Cassini spacecraft orbiting Saturn is providing evidence for space weathering on icy bodies. The Cassini Visible and Infrared Mapping Spectrometer (VIMS) instrument has spatially mapped satellite surfaces and the rings from 0.35-5 microns and the Ultraviolet Imaging Spectrograph (UVIS) instrument from 0.1 to 0.2 microns. These data have sampled a complex mixing space between H2O ice and non-ice components and they show some common spectral properties. Similarly, spectra of the icy Galilean satellites and satellites in the Uranian system have some commonality in spectral properties with those in the Saturn system. The UV absorber is spectrally similar on many surfaces. VIMS has identified CO2, H2 and trace organics in varying abundances on Saturn's satellites. We postulate that through the spatial relationships of some of these compounds that they are created and destroyed through space weathering effects. For example, the trapped H2 and CO2 observed by VIMS in regions with high concentrations of dark material may in part be space weathering products from the destruction of H2O and organic molecules. The dark material, particularly on Iapetus which has the highest concentration in the Saturn system, is well matched by space-weathered silicates in the .4 to 2.6 micron range, and the spectral shapes closely match those of the most mature lunar soils, another indicator of space weathered material.

  20. Analysis of periodic orbits about the Martian moons by continuation techniques

    NASA Astrophysics Data System (ADS)

    Luria, Frank

    1990-12-01

    From a few known periodic orbits of Phobos and Deimos, continuation techniques were used to find entire families of stable orbits. These techniques involved varying a parameter, the Hamiltonian, of the system and analyzing how the orbital behavior changed with the parameter. Floquet multipliers, for stability analysis, were also computed. AUTO86, a continuation/bifurcation software package, was used in this study. Artificial energy dissipation had to be added to the conservative Hamiltonian system to enable use of AUTO.

  1. Modeling the Radiance of the Moon for On-orbit Calibration

    USGS Publications Warehouse

    Stone, T.C.; Kieffer, H.H.; Becker, K.J.

    2003-01-01

    The RObotic Lunar Observatory (ROLO) project has developed radiometric models of the Moon for disk-integrated irradiance and spatially resolved radiance. Although the brightness of the Moon varies spatially and with complex dependencies upon illumination and viewing geometry, the surface photometric properties are extremely stable, and therefore potentially knowable to high accuracy. The ROLO project has acquired 5+ years of spatially resolved lunar images in 23 VNIR and 9 SWIR filter bands at phase angles up to 90??. These images are calibrated to exoatmospheric radiance using nightly stellar observations in a band-coupled extinction algorithm and a radiometric scale based upon observations of the star Vega. An effort is currently underway to establish an absolute scale with direct traceability to NIST radiometric standards. The ROLO radiance model performs linear fitting of the spatially resolved lunar image data on an individual pixel basis. The results are radiance images directly comparable to spacecraft observations of the Moon. Model-generated radiance images have been produced for the ASTER lunar view conducted on 14 April 2003. The radiance model is still experimental - simplified photometric functions have been used, and initial results show evidence of computational instabilities, particularly at the lunar poles. The ROLO lunar image dataset is unique and extensive and presents opportunities for development of novel approaches to lunar photometric modeling.

  2. EuroMoonMars Field Campaign: Geology traverse planning using orbital sub-m imagery

    NASA Astrophysics Data System (ADS)

    Svendsen, Åse; van't Woud, Hans; Samurovic, Dejan; Nebergall, Kent; Battler, Melissa; Orgel, Csilla; Stoker, Carol; Tolboom, Iwan; Foing, Bernard; Team EuroMoonMars

    2013-04-01

    Most of the information we have from Moon and Mars surface, comes from satellite observations. During the selection of landing sites and planning of traverses on unfamiliar planetary sites, satellite images of high resolution is crucial. But what information are we missing from these images? What kind of surprises can be expected when exploring an area that has only been investigated from satellite images? During ILEWG EuroMoonMars 2013 campaign at MDRS Utah we made a comparative study where we looked at satellite images with a spatial resolution of 50-60 cm per pixel, something that is comparable to the resolution of MRO HiRise on Mars or LROC on the Moon. We then planned traverses at MDRS that were as similar to geomorphological features seen at the Gale crater as possible. Following this, we explored these traverses with a rover, drone and walked them in a Mars EVA simulation mode, before taking rocks and soil samples. We shal also discuss the usability of a drone for imaging reconnaissance. The poster will present the results, experiences and lessons learnt from this campaign concerning geological traverse planning based on high resolution satellite images.

  3. ICI Showcase House Prototype

    SciTech Connect

    2009-02-16

    Building Science Corporation collaborated with ICI Homes in Daytona Beach, FL on a 2008 prototype Showcase House that demonstrates the energy efficiency and durability upgrades that ICI currently promotes through its in-house efficiency program called EFactor.

  4. Abort Options for Human Missions to Earth-Moon Halo Orbits

    NASA Technical Reports Server (NTRS)

    Jesick, Mark C.

    2013-01-01

    Abort trajectories are optimized for human halo orbit missions about the translunar libration point (L2), with an emphasis on the use of free return trajectories. Optimal transfers from outbound free returns to L2 halo orbits are numerically optimized in the four-body ephemeris model. Circumlunar free returns are used for direct transfers, and cislunar free returns are used in combination with lunar gravity assists to reduce propulsive requirements. Trends in orbit insertion cost and flight time are documented across the southern L2 halo family as a function of halo orbit position and free return flight time. It is determined that the maximum amplitude southern halo incurs the lowest orbit insertion cost for direct transfers but the maximum cost for lunar gravity assist transfers. The minimum amplitude halo is the most expensive destination for direct transfers but the least expensive for lunar gravity assist transfers. The on-orbit abort costs for three halos are computed as a function of abort time and return time. Finally, an architecture analysis is performed to determine launch and on-orbit vehicle requirements for halo orbit missions.

  5. The Effects of Moon¡¯s Uneven Mass Distribution on the Critical Inclinations of a Lunar Orbiter

    NASA Astrophysics Data System (ADS)

    Rahoma, Walid A.; Abd El-Salam, Fawzy A.

    2014-12-01

    The uneven mass distribution of the Moon highly perturbs the lunar spacecrafts. This uneven mass distribution leads to peculiar dynamical features of the lunar orbiters. The critical inclination is the value of inclination which keeps the deviation of the argument of pericentre from the initial values to be zero. Considerable investigations have been performed for critical inclination when the gravity field is assumed to be symmetric around the equator, namely for oblate gravity field to which Earth¡¯s satellites are most likely to be subjected. But in the case of a lunar orbiter, the gravity field of mass distribution is rather asymmetric, that is, sectorial, and tesseral, harmonic coefficients are big enough so they can¡¯t be neglected. In the present work, the effects of the first sectorial and tesseral harmonic coefficients in addition to the first zonal harmonic coefficients on the critical inclination of a lunar artificial satellite are investigated. The study is carried out using the Hamiltonian framework. The Hamiltonian of the problem is cconstructed and the short periodic terms are eliminated using Delaunay canonical variables. Considering the above perturbations, numerical simulations for a hypothetical lunar orbiter are presented. Finally, this study reveals that the critical inclination is quite different from the critical inclination of traditional sense and/or even has multiple solutions. Consequently, different families of critical inclination are obtained and analyzed.

  6. Potential Biospheres of the icy world in our solar systems

    NASA Astrophysics Data System (ADS)

    de Vera, Jean-Pierre Paul; Baqué, Mickael

    2016-04-01

    The challenge in astrobiology and planetary research in the near future is to realize space missions to study the habitability of Mars and the icy moons of the Jovian and Saturnian systems. Mars is an interesting object to search for habitable environments and for fossilized (and potentially present) life because of its past water driven wet history. On the other hand the Jovian moon Europa and the Saturnian moon Enceladus are promising candidates, where liquid water oceans beneath the surface are expected. These oceans can be habitable environments and the next challenge is to search there for present life. Some examples on potential biospheres and their biosignatures in Mars-like environments and in environmental conditions with reference to the icy moons will be given, which might exist in such kind of icy environments.

  7. Composition of the Moon as Determined from Orbit by Gamma-Ray Spectroscopy

    NASA Technical Reports Server (NTRS)

    Metzger, A. E.

    1994-01-01

    A spacecraft placed in a planetary orbit of suitably high inclination will pass over all or most of the planet's surface in a matter of several weeks to months. The quite prodigious scientific potential of planetary orbiters lies in coupling this comprehensive coverage with observing systems capable of gathering data on properties that include elemental and mineralogic composition, exogenic and endogenic surface alterations, thermal balance, gravity, topography, stratigraphy, albedo and magnetism.

  8. Building Small Icy Bodies: the Process of Icy Grain Aggregation

    NASA Astrophysics Data System (ADS)

    Fraser, Helen Jane; Hill, Catherine Rachel; Blum, Jurgen; Heisselmann, Daniel

    2015-08-01

    The material remaining in proto-planetary disks provides the ingredients from which planetessimals, and eventually comets, asteroids and planets (including their ring and moon systems) evolve. Aggregation processes are thought to proceed much more rapidly beyond snow-lines in such disks, aided by icy mantles on dust grains, but we do not know nano- and micron-scale dust combines to kilometer-sizes. Recent ALMA observations have proven the existence of snow lines in other proto-planetary systems (Qi et al Science (2013)), so it is by studying icy collisions in the laboratory that we can begin to understand the assembly of the icy bodies in our Solar System.Icy particles (between 4.7 and 10.8 mm in diameter) were collided at relative collision velocities of 0.27 - 0.51 m s-1, at 131 - 160 K, under microgravity conditions using a purpose-built experiment (Salter et al Rev Sci Inst (2010)). Bouncing was observed in the majority of collisions, across a full range of normalized impact parameters (b/R = 0.0-1.0). Coefficients of restitution were evenly spread between 0.08 and 0.65 with an average value of 0.36, leading to a minimum of 58% of translational energy being lost in the collision. The range of coefficients of restitution was attributed to the surface roughness of the particles. Analysis of particle rotation showed that up to 17% of the energy of the particles before the collision was converted into rotational energy. Temperature did not affect the coefficients of restitution over the range studied (Hill et all A&A (2015a)). The effects of chemical composition on the collisional outcomes were also studied, at relative particle impact velocities between 0.01 and 0.19 ms-1, temperatures between 131 and 160 K and a pressure of around 10-5 mbar. Overall the collisional properties of the icy particles were unchanged (Hill et al A&A (2015b)).The implications of these experimental results will be discussed in terms of our understanding of the formation and evolution of

  9. 400th Anniversary of Marius's Book with the First Image of an Astronomical Telescope and of Orbits of Jovian Moons

    NASA Astrophysics Data System (ADS)

    Pasachoff, Jay M.; Leich, Pierre

    2015-01-01

    Simon Mayr's (Marius's) Mundus Iovialis Anno M·DC·IX Detectus Ope Perspicilli Belgici (The World of Jupiter...) was published in Nuremberg in 1614; Marius was the Ansbach court mathematician. The frontispiece includes not only a portrait of Marius (1573-1624) himself but also, in the foreground, a long tube labelled "perspicillum," the first known image of a telescopic device used for astronomy; the name "telescope" came later. A schematic diagram of Jupiter with four moons orbiting appears at upper left; Marius, following a suggestion from Kepler, gave these Galilean satellites the names now still in use: Io, Europa. Ganymede, and Callisto. The title continues Hoc est, Quatuor Joviali cum Planetarum, cum Theoria, tum Tabulae, Propriis Observationibus Maxime Fundate.... A pair of conferences was held in Germany in 2014 to commemorate the 400th anniversary of Marius's book and to discuss Marius's work and its relation to Galileo's work (http://www.simon-marius.net; http://www.simon-marius.net/index.php?lang=en&menu=1 28 languages are available). Marius (Mayr) had independently discovered the four satellites of Jupiter, apparently one day after Galileo, on December 29 O.S., 1609; by the time he published his work four years later (a local-circulation publication had appeared in Nuremberg in 1611 in Prognosticon Astrologicum auf das Jahr 1612), Galileo had gained fame and priority, and Galileo accused Marius of plagiarism in Il Saggiatore (1623). With his Belgian telescope, Marius also noted the tilt of the orbital plane of Jupiter's moons, sunspots (1611), and the Andromeda Nebula (1612). He claimed to have worked out a system of cosmology similar to the Tychonic system in 1596, contemporaneously to Kepler's Mysterium Cosmographicum. A crater, the Marius Hills, and the Rima Marius on the Moon are named for him by the I.A.U., as well as, to celebrate the quadricentennial, a main-belt asteroid, now (7984) Marius. Acknowledgment: JMP thanks Seth Fagen, PRPH Books in

  10. Our Battered Moon

    ERIC Educational Resources Information Center

    Damonte, Kathleen

    2004-01-01

    Most people have probably heard the tale about the Moon being made out of Swiss cheese because, on Earth, the Moon looks like it is full of holes. Those holes are actually impact craters, circular depressions that formed when objects, such as rocks that orbit the Sun, smashed into the surface of the Moon. The activity described in this article,…

  11. Chaos in navigation satellite orbits caused by the perturbed motion of the Moon

    NASA Astrophysics Data System (ADS)

    Rosengren, Aaron J.; Alessi, Elisa Maria; Rossi, Alessandro; Valsecchi, Giovanni B.

    2015-06-01

    Numerical simulations carried out over the past decade suggest that the orbits of the Global Navigation Satellite Systems are unstable, resulting in an apparent chaotic growth of the eccentricity. Here, we show that the irregular and haphazard character of these orbits reflects a similar irregularity in the orbits of many celestial bodies in our Solar system. We find that secular resonances, involving linear combinations of the frequencies of nodal and apsidal precession and the rate of regression of lunar nodes, occur in profusion so that the phase space is threaded by a devious stochastic web. As in all cases in the Solar system, chaos ensues where resonances overlap. These results may be significant for the analysis of disposal strategies for the four constellations in this precarious region of space.

  12. Lagrange L4/L5 points and the origin of our Moon and Saturn's moons and rings.

    PubMed

    Gott, J Richard

    2005-12-01

    The current standard theory of the origin of the Moon is that the Earth was hit by a giant impactor the size of Mars causing ejection of debris from its mantle that coalesced to form the moon; but where did this Mars-sized impactor come from? Isotopic evidence suggests that it came from 1 AU radius in the solar nebula, and computer simulations are consistent with its approaching Earth on a zero-energy parabolic trajectory. How could such a large object form at 1 AU in a quiescent disk of planetesimals without having already collided with the Earth at an earlier epoch before having the chance to grow large? Belbruno and Gott propose that the giant impactor could have formed in a stable orbit from debris at the Earth's Lagrange point L(5) (or L(4)). It would grow quietly by accretion at L(5) (or L(4)), but eventually gravitational perturbations by other growing planetesimals would kick it out into a horseshoe orbit and finally into a chaotic creeping orbit, which Belbruno and Gott show would, with high probability, hit the Earth on a near zero-energy parabolic trajectory. We can see other examples of this phenomenon occurring in the solar system. Asteroid 2002AA29 is in a horseshoe orbit relative to the Earth that looks exactly like the horseshoe orbits that Belbruno and Gott found for objects that had been perturbed from L(4)/L(5). The regular moons of Saturn are made of ice and have the same albedo as the ring particles (ice chunks, plus some dust). We (J. R. Gott, R. Vanderbei, and E. Belbruno) propose that the regular icy moons of Saturn (out to the orbit of Titan), which are all in nearly circular orbits, formed out of a thin disk of planetesimals (ice chunks) rather like the rings of Saturn today only larger in extent. In such a situation formation of objects at L(4)/L(5) might be expected. Indeed, Saturn's moon Dione is accompanied by moons (Helene and Polydeuces) at both L(4) and L(5) Lagrange points, and Saturn's moon Tethys is also accompanied by moons

  13. New Morphometric Measurements of Peak-Ring Basins on Mercury and the Moon: Results from the Mercury Laser Altimeter and Lunar Orbiter Laser Altimeter

    NASA Technical Reports Server (NTRS)

    Baker, David M. H.; Head, James W.; Prockter, Louise M.; Fassett, Caleb I.; Neumann, Gregory A.; Smith, David E.; Solomon, Sean C.; Zuber, Maria T.; Oberst, Juergen; Preusker, Frank; Gwiner, Klaus

    2012-01-01

    Peak-ring basins (large impact craters exhibiting a single interior ring) are important to understanding the processes controlling the morphological transition from craters to large basins on planetary bodies. New image and topography data from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) and Lunar Reconnaissance Orbiter (LRO) spacecraft have helped to update the catalogs of peak-ring basins on Mercury and the Moon [1,2] and are enabling improved calculations of the morphometric properties of these basins. We use current orbital altimeter measurements from the Mercury Laser Altimeter (MLA) [3] and the Lunar Orbiter Laser Altimeter (LOLA) [4], as well as stereo-derived topography [5], to calculate the floor depths and peak-ring heights of peak-ring basins on Mercury and the Moon. We present trends in these parameters as functions of rim-crest diameter, which are likely to be related to processes controlling the onset of peak rings in these basins.

  14. OASIS: Organics Analyzer for Sampling Icy Surfaces

    NASA Technical Reports Server (NTRS)

    Getty, S. A.; Dworkin, J. P.; Glavin, D. P.; Martin, M.; Zheng, Y.; Balvin, M.; Southard, A. E.; Ferrance, J.; Malespin, C.

    2012-01-01

    Liquid chromatography mass spectrometry (LC-MS) is a well established laboratory technique for detecting and analyzing organic molecules. This approach has been especially fruitful in the analysis of nucleobases, amino acids, and establishing chirol ratios [1 -3]. We are developing OASIS, Organics Analyzer for Sampling Icy Surfaces, for future in situ landed missions to astrochemically important icy bodies, such as asteroids, comets, and icy moons. The OASIS design employs a microfabricated, on-chip analytical column to chromatographically separate liquid ana1ytes using known LC stationary phase chemistries. The elution products are then interfaced through electrospray ionization (ESI) and analyzed by a time-of-flight mass spectrometer (TOF-MS). A particular advantage of this design is its suitability for microgravity environments, such as for a primitive small body.

  15. Utilizing the Lunar Laser Ranging datasets alongside the radioscience data from the Lunar Reconnaissance Orbiter to improve the dynamical model of the Moon

    NASA Astrophysics Data System (ADS)

    Viswanathan, Vishnu; Fienga, Agnes; Laskar, Jacques; Manche, Herve; Torre, Jean-Marie; Courde, Clément; Exertier, Pierre

    2015-08-01

    In this poster we elaborate the use of raw navigation data (range and Doppler observations) from the Lunar Reconnaissance Orbiter (LRO) available on the Planetary Data System (PDS), in order to study the orbit of this probe using the orbit determination software (GINS) developed by the French space agency (CNES). The constraints that are derived from this process on combining with the high precision Lunar Laser Ranging (LLR) datasets which are spread over 40 years, facilitates an improved dynamical modeling of the Moon. In addition, the possible advantages that could be exploited by the LLR experiments when operated with lasers in the IR wavelength are analyzed.

  16. Shepherd Moons

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Click on the image for movie of Shepherd Moons

    The New Horizons spacecraft took the best images of Jupiter's charcoal-black rings as it approached and then looked back at Jupiter in February 2007. This sequence of pictures from the Long Range Reconnaissance Imager (LORRI) shows the well-defined lanes of gravel- to boulder-sized material composing the bulk of the rings; labels point out how these narrow rings are confined in their orbits by small 'shepherding' moons (Metis and Adrastea).

  17. Strong orbital expansion of Saturn’s inner ice-rich moons through ring torques and mutual resonances during their accretion from a massive ring

    NASA Astrophysics Data System (ADS)

    Salmon, Julien; Canup, Robin M.

    2015-11-01

    Saturn has a diversity of moons with possibly diverse origins. Titan likely formed in Saturn’s sub-nebula (e.g., Canup & Ward 2006). The small moons interior to Mimas are likely recent aggregates of ring’s material spreading through the Roche limit (Charnoz et al. 2010). The origin of the mid-size moons, Mimas through Rhea, is debated. Charnoz et al. (2011) considered a massive ice-rock ring and strong tidal dissipation in Saturn (Q ~ 103), and found that moons out to Rhea could be spawned from such a ring. However such a small value for Q for Saturn is debated. In addition, capture into mutual Mean Motion Resonances (MMR) and resulting eccentricity growth (not included in the Charnoz et al. (2011) model) could lead to orbital destabilization as the moons tidally expand over such large distances (Peale & Canup 2015).Here we consider weak planetary tides (Q ≥ 104) and investigate whether Mimas, Enceladus and Tethys could have been spawned from a massive ice ring (Canup 2010). In this scenario, the rock in these moons would be delivered by material from outside the rings, e.g. by heliocentric impactors during the LHB (Canup 2013). We have expanded a numerical model developed to study the Moon’s accretion (Salmon and Canup 2012, 2014), which couples an analytic Roche-interior disk model to the N-body code SyMBA (Duncan et al. 1998) for satellites, so that we can directly track their accretion and mutual interactions (including MMRs), as well as their tidal interaction with the planet. We consider an initially large Saturn (Fortney et al. 2007) and its progressive contraction, which impacts the strength of tides and the location of the corotation resonance. We perform simulations with and without Dione and Rhea, and study the influence of tidal dissipation into the moons.We find that recoil of the moons due to ring torques, together with capture of moons into MMRs, can produce a distribution similar to that observed. If tidal dissipation in the moons was weak

  18. COMPASS Final Report: Saturn Moons Orbiter Using Radioisotope Electric Propulsion (REP): Flagship Class Mission

    NASA Technical Reports Server (NTRS)

    Oleson, Steven R.; McGuire, Melissa L.

    2011-01-01

    The COllaborative Modeling and Parametric Assessment of Space Systems (COMPASS) team was approached by the NASA Glenn Research Center (GRC) In-Space Project to perform a design session to develop Radioisotope Electric Propulsion (REP) Spacecraft Conceptual Designs (with cost, risk, and reliability) for missions of three different classes: New Frontier s Class Centaur Orbiter (with Trojan flyby), Flagship, and Discovery. The designs will allow trading of current and future propulsion systems. The results will directly support technology development decisions. The results of the Flagship mission design are reported in this document

  19. X-Ray Probes of Jupiter's Auroral Zones, Galilean Moons, and the Io Plasma Torus

    NASA Technical Reports Server (NTRS)

    Elsner, R. F.; Ramsey, B. D.; Swartz, D. A.; Rehak, P.; Waite, J. H., Jr.; Cooper, J. F.; Johnson, R. E.

    2005-01-01

    Remote observations from the Earth orbiting Chandra X-ray Observatory and the XMM-Newton Observatory have shown the the Jovian system is a rich and complex source of x-ray emission. The planet's auroral zones and its disk are powerful sources of x-ray emission, though with different origins. Chandra observations discovered x-ray emission from the Io plasma torus and from the Galilean moons Io, Europa, and possibly Ganymede. The emission from the moons is due to bombardment of their surfaces by highly energetic magnetospheric protons, and oxygen and sulfur ions, producing fluorescent x-ray emission lines from the elements in their surfaces against an intense background continuum. Although very faint when observed from Earth orbit, an imaging x-ray spectrometer in orbit around the icy Galilean moons would provide a detail mapping of the elemental composition in their surfaces. Here we review the results of Chandra and XMM-Newton observations of the Jovian system and describe the characteristics of X-MIME, an imaging x-ray spectrometer undergoing study for possible application to future missions to Jupiter such as JIMO. X-MIME has the ultimate goal of providing detailed high-resolution maps of the elemental abundances of the surfaces of Jupiter's icy moons and Io, as well as detailed study of the x-ray mission from the Io plasma torus, Jupiter's auroral zones, and the planetary disk.

  20. Computer simulation model for early post-capture phase of lunar orbital evolution: implications for thermal history of Earth and Moon

    SciTech Connect

    Malcuit, R.J.; Winters, R.R.

    1985-01-01

    Gravitational capture of a lunar-sized body entails dissipation of about 2 x 10/sup 35/ ergs within the bodies of Earth and Moon by body tides during a close gravitational encounter. For capture to occur, the deformation constants (Love numbers) must be sufficiently high and Q (specific energy dissipation factor) must be sufficiently low. Initial conditions for the two-body orbital simulation are perigee = 20 R/sub e/ (Earth radii), apogee = 270 R/sub e/, and semi-minor axis = 73 R/sub e/. This early post-capture orbit has angular momentum equivalent to a circular lunar orbit of 40 R/sub e/. For simplification, the effects of Earth rotation are neglected and Love numbers are held constant during each calculation. The main variable controlling orbital evolution is Q. Since about 7 x 10/sup 35/ ergs must be dissipated for capture and subsequent orbital circularization, the bodies of both Earth and Moon are heated considerably. Using the Love numbers given above, about 10% of the energy goes to Earth and about 90% goes to Moon. Although the 10% allocated to Earth would be sufficient to melt only a thin zone of mantle material, the combination of energy dissipation and tidal action during such as orbital circularization scenario could lead to enhanced rates of crustal spreading and subduction on an already warm Earth. The authors think that this thermal episode may be sufficient to cause widespread destruction and/or metamorphism of the ancient crust of Earth. They suggest that lunar capture and subsequent early geocentric orbital evolution occurred about 3.9 billion years ago.

  1. A Secondary Ion Mass Analyzer for Remote Surface Composition Analysis of the Galilean Moons

    NASA Technical Reports Server (NTRS)

    Krueger, H.; Srama, R.; Johnson, T. V.; Henkel, H.; vonHoerner, H.; Koch, A.; Horanyi, M.; Gruen, E.; Kissel, J.; Krueger, F.

    2003-01-01

    Galileo in-situ dust measurements have shown that the Galilean moons are surrounded by tenuous dust clouds formed by collisional ejecta from their icy surfaces, kicked up by impacts of interplanetary micrometeoroids. The majority of the ejecta dust particles have been sensed at altitudes below five between 0.5 and 1 micron, just above the detector threshold, indicating a size distribution decreasing towards bigger particles. their parent bodies. They carry information about the properties of the surface from which they have been kicked up. In particular, these grains may carry organic compounds and other chemicals of biological relevance if they exist on the icy Galilean moons. In-situ analysis of the grain composition with a sophisticated dust analyzer instrument flying on a Jupiter Icy Moons Orbiter can provide important information about geochemical and geophysical processes during the evolutionary histories of these moons which are not accessible with other techniques from an orbiter spacecraft. Thus, spacecraft-based in-situ dust measurements can be used as a diagnostic tool for the analysis of the surface composition of the moons. This way, the in-situ measurements turn into a remote sensing technique by using the dust instrument like a telescope for surface investigation. An instrument capable of very high resolution composition analysis of dust particles is the Cometary Secondary Ion Mass Analyzer (COSIMA). The instrument was originally developed for the Comet Rendezvous and Asteroid Flyby (CRAF) mission and has now been built for ESA'S comet orbiter Rosetta. Dust particles are collected on a target and are later located by an optical microscope camera. A pulsed primary indium ion gun partially ionizes the dust grains. The generated secondary ions are accelerated in an electric field and travel through a reflectron-type time-of-flight ion mass spectrometer.

  2. Inelastic neutron scatter iron concentrations of the moon from orbital gamma ray data

    NASA Technical Reports Server (NTRS)

    Davis, P. A., Jr.; Bielefeld, M. J.

    1981-01-01

    The considered investigation is concerned with the relation between KREEP and thermal neutron flux depression. The Fe(n, n-prime gamma) concentrations of selected lunar regions were calculated by energy-band analysis of the 0.803-0.872 MeV band. The result of the investigation will be used to evaluate the reliability of the previously determined Fe(n, gamma) values. A 0.803-0.872 MeV band was isolated from the Apollo 15 and 16 orbital gamma ray spectra. Preliminary regression analysis of regional ground truth count rates and Fe concentrations showed this energy interval to be optimum for the 0.8467 MeV inelastic scatter (n, n-prime gamma)Fe peak.

  3. Natural motion around the Martian moon Phobos: the dynamical substitutes of the Libration Point Orbits in an elliptic three-body problem with gravity harmonics

    NASA Astrophysics Data System (ADS)

    Zamaro, M.; Biggs, J. D.

    2015-07-01

    The Martian moon Phobos is becoming an appealing destination for future scientific missions. The orbital dynamics around this planetary satellite is particularly complex due to the unique combination of both small mass-ratio and length-scale of the Mars-Phobos couple: the resulting sphere of influence of the moon is very close to its surface, therefore both the classical two-body problem and circular restricted three-body problem (CR3BP) do not provide an accurate approximation to describe the spacecraft's dynamics in the vicinity of Phobos. The aim of this paper is to extend the model of the CR3BP to consider the orbital eccentricity and the highly-inhomogeneous gravity field of Phobos, by incorporating the gravity harmonics series expansion into an elliptic R3BP, named ER3BP-GH. Following this, the dynamical substitutes of the Libration Point Orbits (LPOs) are computed in this more realistic model of the relative dynamics around Phobos, combining methodologies from dynamical systems theory and numerical continuation techniques. Results obtained show that the structure of the periodic and quasi-periodic LPOs differs substantially from the classical case without harmonics. Several potential applications of these natural orbits are presented to enable unique low-cost operations in the proximity of Phobos, such as close-range observation, communication, and passive radiation shielding for human spaceflight. Furthermore, their invariant manifolds are demonstrated to provide high-performance natural landing and take-off pathways to and from Phobos' surface, and transfers from and to Martian orbits. These orbits could be exploited in upcoming and future space missions targeting the exploration of this Martian moon.

  4. Laser 'Footprints' on the Moon

    NASA Video Gallery

    As the Lunar Reconnaissance Orbiter (LRO) circles the moon, a sophisticated instrument bounces laser light off the moon's surface 28 times per second. An array of five sensors arranged in an X-shap...

  5. A new 4-D dynamical modelling of the Moon orbital and rotational motion developed at POLAC

    NASA Astrophysics Data System (ADS)

    Bourgoin, A.; Le Poncin-Lafitte, C.; Bouquillon, S.; Francou, G.; Angonin, M.-C.

    2015-12-01

    Nowadays, General Relativity (GR) is very well tested within the Solar System using observables given by the tracking of spacecraft tep{2003Natur.425..374B}, Very Long Baseline Interferometry tep{2009A&A...499..331L,2011A&A...529A..70L} and Lunar Laser Ranging -LLR- tep{2010LRR....13....7M}. These tests are mainly based on two frameworks: the Parametrized Post Newtonian (PPN) and the search for a fifth force. However other frameworks are available and can be used to look for deviations from GR. In this context, we present the ongoing work concerning LLR performed at POLAC (Paris Observatory Lunar Analysis Center) in SYRTE, Paris Observatory. We focus on a new generation of software that simulates the observable (the round trip time of photons) from a given space-time metric tep{2012CQGra..29w5027H}. This flexible approach allows to perform simulations in any alternative metric theories of gravity. The output of these software provides templates of anomalous residuals that should show up in real data if the underlying theory of gravity is not GR. Those templates can be used to give a rough estimation of the constraints on the additional parameters involved in the alternative theory. To succeed, we are building a numerical lunar ephemeris which integrates the differential equations governing the orbital and rotational motion of bodies in the Solar System. In addition, we integrate the difference between the Terrestrial Time (TT) and the Barycentric Dynamical Time (TDB) to make the ephemeris self-consistent. Special attention is paid to the computation of partial derivatives since they are integrated numerically from the variational equations.

  6. Rapid trajectory design in the Earth-Moon ephemeris system via an interactive catalog of periodic and quasi-periodic orbits

    NASA Astrophysics Data System (ADS)

    Guzzetti, Davide; Bosanac, Natasha; Haapala, Amanda; Howell, Kathleen C.; Folta, David C.

    2016-09-01

    Upcoming missions and prospective design concepts in the Earth-Moon system extensively leverage multi-body dynamics that may facilitate access to strategic locations or reduce propellant usage. To incorporate these dynamical structures into the mission design process, Purdue University and the NASA Goddard Flight Space Center have initiated the construction of a trajectory design framework to rapidly access and compare solutions from the circular restricted three-body problem. This framework, based upon a 'dynamic' catalog of periodic and quasi-periodic orbits within the Earth-Moon system, can guide an end-to-end trajectory design in an ephemeris model. In particular, the inclusion of quasi-periodic orbits further expands the design space, potentially enabling the detection of additional orbit options. To demonstrate the concept of a 'dynamic' catalog, a prototype graphical interface is developed. Strategies to characterize and represent periodic and quasi-periodic information for interactive trajectory comparison and selection are discussed. Two sample applications for formation flying near the Earth-Moon L2 point and lunar space infrastructures are explored to demonstrate the efficacy of a 'dynamic' catalog for rapid trajectory design and validity in higher-fidelity models.

  7. Moon Rise, Moon Set.

    ERIC Educational Resources Information Center

    Redman, Christine

    2001-01-01

    Points out the potential of the moon as a rich teaching resource for subject areas like astronomy, physics, and biology. Presents historical, scientific, technological, and interesting facts about the moon. Includes suggestions for maximizing student interest and learning about the moon. (YDS)

  8. Lighting Conditions for the Moon's Poles: Integrating Clementine, Kaguya, and Lunar Reconnaissance Orbiter Data Sets

    NASA Astrophysics Data System (ADS)

    Quinn, D. P.; Cahill, J.; Bussey, B.; McGovern, A.; Spudis, P.; Noda, H.; Ishihara, Y.

    2010-12-01

    Lunar poles experience extreme variations in illumination. Areas of permanent shadow and near-permanent illumination are located in close proximity and are attractive candidates for a sustained presence, exploration, and resource exploitation. Here we use Kaguya and Lunar Reconnaissance Orbiter (LRO) laser-altimeter (LALT and LOLA) digital topography models (DTMs) to simulate illumination conditions for both lunar poles using the software LunarShader. Previous comparisons between Clementine optical images and illumination maps derived from Kaguya LALT data suggest accurate and precise prediction of polar lighting conditions (Bussey et al. 2010). Here, maps predicting areas of illumination or shadow are generated at 12-hour intervals for the hypothetical year 2020. Average illumination maps computed from these data for time periods of one month to a year enable the identification and analysis of regions of both sustained illumination or permanent shadow and account for seasonal variations. Temporal illumination profiles are also generated for locations with more sustained illumination for more detailed analysis. Previous analyses focused on models derived from Kaguya DTM’s with high (64 pixels/degree) and low (128 pixels/degree) resolution data sets extending 5° and 10° from each pole (Bussey et al. 2010; Cahill et al. 2010). This work integrates LOLA data (~126 pixels/degree), which extends to 80° latitude. A comparison of average illumination for the three models prepared for the North pole predict similar durations of illumination during the year 2020. Kaguya low- and high-resolution models predict the region with the most sustained illumination will be lit 89% and 86% of the year, respectively. The illumination model computed from LRO’s LOLA data predicts this location will be lit 90% of year. At the South Pole, Kaguya high-resolution data simulations predict an illumination of 78%, 8-10% lower than the other data sets (86% for the Kaguya low

  9. The transition from complex craters to multi-ring basins on the Moon: Quantitative geometric properties from Lunar Reconnaissance Orbiter Lunar Orbiter Laser Altimeter (LOLA) data

    NASA Astrophysics Data System (ADS)

    Baker, David M. H.; Head, James W.; Neumann, Gregory A.; Smith, David E.; Zuber, Maria T.

    2012-03-01

    The morphologic transition from complex impact craters, to peak-ring basins, and to multi-ring basins has been well-documented for decades. Less clear has been the morphometric characteristics of these landforms due to their large size and the lack of global high-resolution topography data. We use data from the Lunar Orbiter Laser Altimeter (LOLA) instrument onboard the Lunar Reconnaissance Orbiter (LRO) spacecraft to derive the morphometric characteristics of impact basins on the Moon, assess the trends, and interpret the processes involved in the observed morphologic transitions. We first developed a new technique for measuring and calculating the geometric/morphometric properties of impact basins on the Moon. This new method meets a number of criteria that are important for consideration in any topographic analysis of crater landforms (e.g., multiple data points, complete range of azimuths, systematic, reproducible analysis techniques, avoiding effects of post-event processes, robustness with respect to the statistical techniques). The resulting data more completely capture the azimuthal variation in topography that is characteristic of large impact structures. These new calculations extend the well-defined geometric trends for simple and complex craters out to basin-sized structures. Several new geometric trends for peak-ring basins are observed. Basin depth: A factor of two reduction in the depth to diameter (d/Dr) ratio in the transition from complex craters to peak-ring basins may be characterized by a steeper trend than known previously. The d/Dr ratio for peak-ring basins decreases with rim-crest diameter, which may be due to a non-proportional change in excavation cavity growth or scaling, as may occur in the simple to complex transition, or increased magnitude of floor uplift associated with peak-ring formation. Wall height, width, and slope: Wall height and width increase with increasing rim-crest diameter, while wall slope decreases; decreasing ratios

  10. Morphology and Scaling of Ejecta Deposits on Icy Satellites

    NASA Technical Reports Server (NTRS)

    Schenk, Paul M.; Ridolfi, Francis J.; Bredekamp, Joe (Technical Monitor)

    2002-01-01

    Continuous ejecta deposits on Ganymede consist of two major units, or facies: a thick inner hummocky pedestal facies, and a relatively thin outer radially scoured facies defined also by the inner limit of the secondary crater field. Both ejecta facies have a well-defined power-law relationship to crater diameter for craters ranging from 15 to approx. 600 km across. This relationship can be used to estimate the nominal crater diameter for impact features on icy satellites (such as palimpsests and multiring basins) for which the crater rim is no longer recognizable. Ejecta deposits have also been mapped on 4 other icy satellites. Although morphologically similar to eject deposits on the Moon, ejecta deposits for smaller craters are generally significantly broader in extent on the icy satellites, in apparent defiance of predictions of self-similarity. A greater degree of rim collapse and enlargement on the Moon may explain the observed difference.

  11. Phase transitions and convection in icy satellites

    NASA Technical Reports Server (NTRS)

    Bercovici, D.; Schubert, G.; Reynolds, R. T.

    1986-01-01

    The effects of solid-solid phase changes on subsolidus convection in the large icy moons of the outer solar system are considered. Phase transitions affect convection via processes that distort the phase change boundary and/or influence buoyancy through thermal expansion. Linear stability analyses are carried out for ice layers with a phase change at the midplane. Two exothermic phase transitions (ice I - ice II, ice VI - ice VIII) and two endothermic transitions (ice I - ice III, ice II - ice V) are considered. For the exothermic cases, the phase change can either impede or enhance whole-layer convection. For the endothermic cases, the phse change always inhibits whole-layer convective overturn and tends to enforce two-layer convection. These results play some constraints on possible models of icy satellite evolution and structure.

  12. Laboratory simulation of impacts shocks on icy surfaces: application to Europa

    NASA Astrophysics Data System (ADS)

    Nna Mvondo, D.; Khare, B. N.; McKay, C. P.

    Impact processing is an energy source that may have contributed to the supply of organic compounds in the planetary environments of our solar system. Numerous studies related to impact events and organic synthesis have focused on the chemistry occurring in the atmospheres of the early Earth and Titan (McKay and Borucki, 1997; Jones and Lewis, 1987; Borucki et al., 1984). Here we consider their implication for the chemistry occurring on the surface. Recently, it has been suggested that meteorite impacts could be an energy source for organic synthesis in ices (Borucki et al., 2002; McDonald et al., 1996). There is a great interest in meteorite impacts on icy surfaces of the saturnian and jovian moons because their ice crusts may contain carbon, oxygen, and nitrogen-bearing compounds that could participate in synthesizing prebiotic molecules. In Europa, hypervelocity meteorite impacts and fracture may release tidal and tectonic stresses into the icy crust in the form of electrical discharges. Such discharges may provide enough energy for in situ synthesis of organic solids and could be correlated with the orange-brown material observed in Europa in regions located at impact sites (Borucki et al., 2002). Here we investigate by laboratory experiments the possible contribution of meteorite impact as an energy to drive chemical reactions in Europa's icy shell. Shocks during impacts are simulated by energy deposition from a Neodymium-YAG laser emitting a pulse energy of 0.65 J/pulse at a wavelength of 1064 nm. We conduct a series of experiments irradiating ice mixtures of H2O / CH3OH / (NH4)2SO4 at 77K under vacuum. The volatile products of the irradiated ice are then analyzed by GC-MS. This experimental study could be applicable to other icy moons like Titan. Indeed organics accumulated on Titan's surface layer could have been subjected to impact processing (Artemieva et al., 2003;Thompson and Sagan, 1991) and even participate in the formation of products relevant to life

  13. Interior of the Moon

    NASA Technical Reports Server (NTRS)

    Weber, Renee C.

    2013-01-01

    A variety of geophysical measurements made from Earth, from spacecraft in orbit around the Moon, and by astronauts on the lunar surface allow us to probe beyond the lunar surface to learn about its interior. Similarly to the Earth, the Moon is thought to consist of a distinct crust, mantle, and core. The crust is globally asymmetric in thickness, the mantle is largely homogeneous, and the core is probably layered, with evidence for molten material. This chapter will review a range of methods used to infer the Moon's internal structure, and briefly discuss the implications for the Moon's formation and evolution.

  14. Feasibility demonstration for calibrating Suomi-National Polar-Orbiting Partnership Visible Infrared Imaging Radiometer Suite day/night band using Dome C and Greenland under moon light

    NASA Astrophysics Data System (ADS)

    Qiu, Shi; Shao, Xi; Cao, Changyong; Uprety, Sirish

    2016-01-01

    The day/night band (DNB) of the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard Suomi National Polar-orbiting Partnership (Suomi-NPP) represents a major advancement in night time imaging capabilities. DNB covers almost seven orders of magnitude in its dynamic range from full sunlight to half-moon. To achieve this large dynamic range, it uses four charge-coupled device arrays in three gain stages. The low gain stage (LGS) gain is calibrated using the solar diffuser. In operations, the medium and high gain stage values are determined by multiplying the gain ratios between the medium gain stage, and LGS, and high gain stage (HGS) and LGS, respectively. This paper focuses on independently verifying the radiometric accuracy and stability of DNB HGS using DNB observations of ground vicarious calibration sites under lunar illumination at night. Dome C in Antarctica in the southern hemisphere and Greenland in the northern hemisphere are chosen as the vicarious calibration sites. Nadir observations of these high latitude regions by VIIRS are selected during perpetual night season, i.e., from April to August for Dome C and from November to January for Greenland over the years 2012 to 2013. Additional selection criteria, such as lunar phase being more than half-moon and no influence of straylight effects, are also applied in data selection. The lunar spectral irradiance model, as a function of Sun-Earth-Moon distances and lunar phase, is used to determine the top-of-atmosphere reflectance at the vicarious site. The vicariously derived long-term reflectance from DNB observations agrees with the reflectance derived from Hyperion observations. The vicarious trending of DNB radiometric performance using DOME-C and Greenland under moon light shows that the DNB HGS radiometric variability (relative accuracy to lunar irradiance model and Hyperion observation) is within 8%. Residual variability is also discussed.

  15. Evidence for exposed water ice in the Moon's south polar regions from Lunar Reconnaissance Orbiter ultraviolet albedo and temperature measurements

    NASA Astrophysics Data System (ADS)

    Hayne, Paul O.; Hendrix, Amanda; Sefton-Nash, Elliot; Siegler, Matthew A.; Lucey, Paul G.; Retherford, Kurt D.; Williams, Jean-Pierre; Greenhagen, Benjamin T.; Paige, David A.

    2015-07-01

    We utilize surface temperature measurements and ultraviolet albedo spectra from the Lunar Reconnaissance Orbiter to test the hypothesis that exposed water frost exists within the Moon's shadowed polar craters, and that temperature controls its concentration and spatial distribution. For locations with annual maximum temperatures Tmax greater than the H2O sublimation temperature of ∼110 K, we find no evidence for exposed water frost, based on the LAMP UV spectra. However, we observe a strong change in spectral behavior at locations perennially below ∼110 K, consistent with cold-trapped ice on the surface. In addition to the temperature association, spectral evidence for water frost comes from the following spectral features: (a) decreasing Lyman-α albedo, (b) decreasing "on-band" (129.57-155.57 nm) albedo, and (c) increasing "off-band" (155.57-189.57 nm) albedo. All of these features are consistent with the UV spectrum of water ice, and are expected for water ice layers >∼100 nm in thickness. High regolith porosity, which would darken the surface at all wavelengths, cannot alone explain the observed spectral changes at low temperatures. Given the observed LAMP off-band/on-band albedo ratios at a spatial scale of 250 m, the range of water ice concentrations within the cold traps with Tmax < 110 K is ∼0.1-2.0% by mass, if the ice is intimately mixed with dry regolith. If pure water ice is exposed instead, then up to ∼10% of the surface area on the 250-m scale of the measurements may be ice-covered. The observed distribution of exposed water ice is highly heterogeneous, with some cold traps <110 K having little to no apparent water frost, and others with a significant amount of water frost. As noted by Gladstone et al. (Gladstone, G.R. et al. [2012]. J. Geophys. Res.: Planets 117(E12)), this heterogeneity may be a consequence of the fact that the net supply rate of H2O molecules to the lunar poles is very similar to the net destruction rate within the cold

  16. The shadow of Saturn's icy satellites in the E ring

    NASA Astrophysics Data System (ADS)

    Schmidt, J.; Sremcevic, M.

    2008-09-01

    We analyze shadows that Saturnian satellites cast in the E ring, a faint, broad dust ring composed of icy grains. The brightness contrast of a moon's shadow relative to the surrounding ring allows to infer local properties of the size distribution of ring particles. We derive the shadow contrast from a large number of Cassini images of Enceladus taken in various filters in a range of phase angles 144 to 164 degrees. For Tethys and Dione we identify a clear shadow in images with phase angles larger than 160 degrees. From the data we obtain the number density of E ring grains at the orbits of Tethys and Dione relative to the one near Enceladus. The latter we constrain from the variation of the shadow contrast with color and phase angle. From the Enceladus data we construct the phase curve of the E ring dust between 144 and 164 degrees. We compare to data obtained from Earth-bound observations by de Pater et al 2004 and in situ measurements by the Cosmic Dust Analyzer onboard Cassini.

  17. Unveiling the evolution and formation of icy giants

    NASA Astrophysics Data System (ADS)

    Maier, Andrea; Bocanegra, Tatiana; Bracken, Colm; Costa, Marc; Dirkx, Dominic; Gerth, Ingo; Konstantinidis, Konstantinos; Labrianidis, Christos; Laneuville, Matthieu; Luntzer, Armin; MacArthur, Jane; Morschhauser, Achim; Nordheim, Tom; Sallantin, Renaud; Tlustos, Reinhard

    2013-04-01

    The planet Uranus is one of two ice giants in the solar system, both of which have only been visited only once by the Voyager 2 spacecraft. Therefore, a dedicated mission to an ice giant is crucial to deepen our knowledge of the formation, evolution and current characteristics of such a planet and its system. We present the science objectives, architecture rationale and system design for a mission to the Uranian system. We conducted a detailed study on how to best fulfill the primary science goal, namely: To investigate Uranus and its system as an archetype for ice giants. To this end, we formulated specific science questions leading to measurement requirements and, finally, instrument requirements and suitable instruments. The primary science questions relate to investigating Uranus' deep interior and outer layers as these are directly related to the primary science goal. Additionally, investigations of the moons, rings and the magnetosphere will provide complementary observations of the Uranian system specifically and icy giants in general. A trade-off between several mission architectures was performed, such as an orbiter with an atmospheric entry probe and a flyby mission. In this process, the relative importance of the science questions, the capabilities of each concept to carry a certain payload and its capability to answer the science questions in the given architecture were traded off. Similarly, the feasibility of each concept from an engineering point-of-view was assessed, taking into account matters such as complexity, cost and risk. The results are presented as a function of relative engineering and science score weights, providing an envelope of optimal mission selections over a range of mission scenarios. We conclude that a Uranus orbiter with a single entry probe and an extended moon tour fulfills the primary science goal in an optimal manner. The mission scenario is based on a launch date in 2026 on an Ariane 5 ECA launcher and arrival at Uranus in

  18. A permanent, asymmetric dust cloud around the Moon

    NASA Astrophysics Data System (ADS)

    Horányi, M.; Szalay, J. R.; Kempf, S.; Schmidt, J.; Grün, E.; Srama, R.; Sternovsky, Z.

    2015-06-01

    Interplanetary dust particles hit the surfaces of airless bodies in the Solar System, generating charged and neutral gas clouds, as well as secondary ejecta dust particles. Gravitationally bound ejecta clouds that form dust exospheres were recognized by in situ dust instruments around the icy moons of Jupiter and Saturn, but have hitherto not been observed near bodies with refractory regolith surfaces. High-altitude Apollo 15 and 17 observations of a `horizon glow' indicated a putative population of high-density small dust particles near the lunar terminators, although later orbital observations yielded upper limits on the abundance of such particles that were a factor of about 104 lower than that necessary to produce the Apollo results. Here we report observations of a permanent, asymmetric dust cloud around the Moon, caused by impacts of high-speed cometary dust particles on eccentric orbits, as opposed to particles of asteroidal origin following near-circular paths striking the Moon at lower speeds. The density of the lunar ejecta cloud increases during the annual meteor showers, especially the Geminids, because the lunar surface is exposed to the same stream of interplanetary dust particles. We expect all airless planetary objects to be immersed in similar tenuous clouds of dust.

  19. A permanent, asymmetric dust cloud around the Moon.

    PubMed

    Horányi, M; Szalay, J R; Kempf, S; Schmidt, J; Grün, E; Srama, R; Sternovsky, Z

    2015-06-18

    Interplanetary dust particles hit the surfaces of airless bodies in the Solar System, generating charged and neutral gas clouds, as well as secondary ejecta dust particles. Gravitationally bound ejecta clouds that form dust exospheres were recognized by in situ dust instruments around the icy moons of Jupiter and Saturn, but have hitherto not been observed near bodies with refractory regolith surfaces. High-altitude Apollo 15 and 17 observations of a 'horizon glow' indicated a putative population of high-density small dust particles near the lunar terminators, although later orbital observations yielded upper limits on the abundance of such particles that were a factor of about 10(4) lower than that necessary to produce the Apollo results. Here we report observations of a permanent, asymmetric dust cloud around the Moon, caused by impacts of high-speed cometary dust particles on eccentric orbits, as opposed to particles of asteroidal origin following near-circular paths striking the Moon at lower speeds. The density of the lunar ejecta cloud increases during the annual meteor showers, especially the Geminids, because the lunar surface is exposed to the same stream of interplanetary dust particles. We expect all airless planetary objects to be immersed in similar tenuous clouds of dust. PMID:26085272

  20. The Transition from Complex Crater to Peak-Ring Basin on the Moon: New Observations from the Lunar Orbiter Laser Altimeter (LOLA) Instrument

    NASA Technical Reports Server (NTRS)

    Baker, David M. H.; Head, James W.; Fassett, Caleb I.; Kadish, Seth J.; Smith, Dave E.; Zuber, Maria T.; Neumann, Gregory A.

    2012-01-01

    Impact craters on planetary bodies transition with increasing size from simple, to complex, to peak-ring basins and finally to multi-ring basins. Important to understanding the relationship between complex craters with central peaks and multi-ring basins is the analysis of protobasins (exhibiting a rim crest and interior ring plus a central peak) and peak-ring basins (exhibiting a rim crest and an interior ring). New data have permitted improved portrayal and classification of these transitional features on the Moon. We used new 128 pixel/degree gridded topographic data from the Lunar Orbiter Laser Altimeter (LOLA) instrument onboard the Lunar Reconnaissance Orbiter, combined with image mosaics, to conduct a survey of craters >50 km in diameter on the Moon and to update the existing catalogs of lunar peak-ring basins and protobasins. Our updated catalog includes 17 peak-ring basins (rim-crest diameters range from 207 km to 582 km, geometric mean = 343 km) and 3 protobasins (137-170 km, geometric mean = 157 km). Several basins inferred to be multi-ring basins in prior studies (Apollo, Moscoviense, Grimaldi, Freundlich-Sharonov, Coulomb-Sarton, and Korolev) are now classified as peak-ring basins due to their similarities with lunar peak-ring basin morphologies and absence of definitive topographic ring structures greater than two in number. We also include in our catalog 23 craters exhibiting small ring-like clusters of peaks (50-205 km, geometric mean = 81 km); one (Humboldt) exhibits a rim-crest diameter and an interior morphology that may be uniquely transitional to the process of forming peak rings. Comparisons of the predictions of models for the formation of peak-ring basins with the characteristics of the new basin catalog for the Moon suggest that formation and modification of an interior melt cavity and nonlinear scaling of impact melt volume with crater diameter provide important controls on the development of peak rings. In particular, a power-law model of

  1. Supporting Mars exploration: BIOMEX in Low Earth Orbit and further astrobiological studies on the Moon using Raman and PanCam technology

    NASA Astrophysics Data System (ADS)

    de Vera, Jean-Pierre; Boettger, Ute; Noetzel, Rosa de la Torre; Sánchez, Francisco J.; Grunow, Dana; Schmitz, Nicole; Lange, Caroline; Hübers, Heinz-Wilhelm; Billi, Daniela; Baqué, Mickael; Rettberg, Petra; Rabbow, Elke; Reitz, Günther; Berger, Thomas; Möller, Ralf; Bohmeier, Maria; Horneck, Gerda; Westall, Frances; Jänchen, Jochen; Fritz, Jörg; Meyer, Cornelia; Onofri, Silvano; Selbmann, Laura; Zucconi, Laura; Kozyrovska, Natalia; Leya, Thomas; Foing, Bernard; Demets, René; Cockell, Charles S.; Bryce, Casey; Wagner, Dirk; Serrano, Paloma; Edwards, Howell G. M.; Joshi, Jasmin; Huwe, Björn; Ehrenfreund, Pascale; Elsaesser, Andreas; Ott, Sieglinde; Meessen, Joachim; Feyh, Nina; Szewzyk, Ulrich; Jaumann, Ralf; Spohn, Tilman

    2012-12-01

    The Low Earth Orbit (LEO) experiment Biology and Mars Experiment (BIOMEX) is an interdisciplinary and international space research project selected by ESA. The experiment will be accommodated on the space exposure facility EXPOSE-R2 on the International Space Station (ISS) and is foreseen to be launched in 2013. The prime objective of BIOMEX is to measure to what extent biomolecules, such as pigments and cellular components, are resistant to and able to maintain their stability under space and Mars-like conditions. The results of BIOMEX will be relevant for space proven biosignature definition and for building a biosignature data base (e.g. the proposed creation of an international Raman library). The library will be highly relevant for future space missions such as the search for life on Mars. The secondary scientific objective is to analyze to what extent terrestrial extremophiles are able to survive in space and to determine which interactions between biological samples and selected minerals (including terrestrial, Moon- and Mars analogs) can be observed under space and Mars-like conditions. In this context, the Moon will be an additional platform for performing similar experiments with negligible magnetic shielding and higher solar and galactic irradiation compared to LEO. Using the Moon as an additional astrobiological exposure platform to complement ongoing astrobiological LEO investigations could thus enhance the chances of detecting organic traces of life on Mars. We present a lunar lander mission with two related objectives: a lunar lander equipped with Raman and PanCam instruments which can analyze the lunar surface and survey an astrobiological exposure platform. This dual use of testing mission technology together with geo- and astrobiological analyses will significantly increase the science return, and support the human preparation objectives. It will provide knowledge about the Moon's surface itself and, in addition, monitor the stability of life

  2. The Lunar Reconnaissance Orbiter (LRO) at the Dynamic Moon: Five Years of Operations in Lunar Orbit - An Overview of the Mission, Key Science Results, Data Products, and Future Measurements

    NASA Astrophysics Data System (ADS)

    Petro, N. E.; Keller, J. W.

    2014-12-01

    The Lunar Reconnaissance Orbiter (LRO) has been orbiting the Moon for over five years. In that time, data from the seven instruments onboard the spacecraft have made significant advances in our understanding of the Moon and its environment. In September 2014 LRO completed its first Extended Science Mission (ESM) and began a second ESM (pending NASA approval). During the ESM and the second ESM, LRO has been in a quasi-stable, eccentric orbit of ~30 x 180 km with a periapse near the South Pole. This orbit enabled high-resolution measurements around the South Pole. LRO's seven instruments are operating nominally, and have experienced no significant degradation since beginning the ESM. The spacecraft has performed exceptionally well, with 98.4% uptime during the mission. LRO retains sufficient fuel so that its current orbit can be maintained for at least 8 years. LRO's science teams have been extremely productive, focusing on the distribution of volatiles, evidence for early differentiation, measuring the lunar impact record, and the Moon's interactions with its external environment. Three of the most exciting findings by LRO have been the identification of LRO-era impacts, global tectonic features, and the transient nature of some volatiles at the surface. These findings are areas of study for future LRO measurements. LRO's data is released to the PDS every 3 months, as of Aug. 2014 528.75 TB of data have been delivered by LRO. Many of the teams have delivered higher-level data products as part of their routine PDS deliveries (e.g., mosaics, maps, derived products). These products are intended to act as useful resources for the science community. Some higher-level LRO data products are of interest for future lunar landers. These products include illumination maps, meter-scale digital elevation models, roughness maps, and 50cm per pixel images of a range of possible landing sites. All of these products are available either from the PDS [1] or individual teams websites

  3. Orbits of Saturn's Inner Moons and Other Observations Connected with the 1995-1996 Saturnian Ring Plane Crossing

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Keck infrared observations of Saturn's E and G rings during Earth's 1995 Ring Plane Crossing are reported along with the NASA's Mauna Kea IR Telescope Facility (IRTF) observations of Saturn's faint outer rings and small moons in the Near-IR Astronomy Program. Observations of the rings and satellites with the 5-m Hale telescope at Palomar Observatory, following the solar crossing of Saturn's ring plane on 19 Nov. 1995, are also addressed. Images of Saturn at radio wavelengths, the data containing information on the structure and composition of the rings as well as the planet's deep atmosphere between the 1- and 10-bar pressure levels, are discussed.

  4. Moon Phases

    ERIC Educational Resources Information Center

    Riddle, Bob

    2010-01-01

    When teaching Moon phases, the focus seems to be on the sequence of Moon phases and, in some grade levels, how Moon phases occur. Either focus can sometimes be a challenge, especially without the use of models and observations of the Moon. In this month's column, the author describes some of the lessons that he uses to teach the phases of the Moon…

  5. Going for the Moon instead of Just Going into Orbit: The Quest for Approval of the United States' First Lunar-Probe Attempts, 1957-1958

    NASA Astrophysics Data System (ADS)

    Waff, C. B.

    2005-08-01

    The U.S. program for exploring the solar system with spacecraft began with the five Pioneer lunar-probe attempts of 1958-1959, which were initiated prior to the formation of NASA under the auspices of the Department of Defense's newly formed Advanced Research Projects Agency. Although most historical accounts of early U.S. solar-system exploration note the failure of all the probes to get anywhere near the moon (only the final Pioneer 4 probe succeeded in escaping the earth's gravity), virtually no attention has been paid to how these probe attempts came to be approved by President Eisenhower in March 1958. An examination of formerly classified documents at NASA's Jet Propulsion Laboratory and the Space Systems Division History Office at Los Angeles Air Force Base has revealed that while efforts were made to place scientific instrumentation aboard the probes, a major impetus for the approval of the probes and a major factor in their design was a desire by President's Scientific Advisory Committee (PSAC) members and ARPA officials to restore national prestige by surpassing in a very public way the Soviet Union's recent achievement of orbiting the world's first artificial satellite. Although PSAC members ultimately decided visual reconnaissance (i.e., close-up photographs of the lunar surface) was the best means to achieve this goal, they did briefly consider (but rejected) the idea of landing and exploding an atomic bomb on the moon. (This paper is based on research conducted under a NASA-JPL contract.)

  6. Going for the Moon instead of Just Going into Orbit: The Quest for Approval of the United States' First Lunar-Probe Attempts, 1957-1958

    NASA Astrophysics Data System (ADS)

    Waff, C. B.

    2005-12-01

    The U.S. program for exploring the solar system with spacecraft began with the five Pioneer lunar-probe attempts of 1958-1959, which were initiated prior to the formation of NASA under the auspices of the Department of Defense's newly formed Advanced Research Projects Agency. Although most historical accounts of early U.S. solar-system exploration note the failure of all the probes to get anywhere near the moon (only the final Pioneer 4 probe succeeded in escaping the earth's gravity), virtually no attention has been paid to how these probe attempts came to be approved by President Eisenhower in March 1958. An examination of formerly classified documents at NASA's Jet Propulsion Laboratory and the Space Systems Division History Office at Los Angeles Air Force Base has revealed that while efforts were made to place scientific instrumentation aboard the probes, a major impetus for the approval of the probes and a major factor in their design was a desire by President's Scientific Advisory Committee (PSAC) members and ARPA officials to restore national prestige by surpassing in a very public way the Soviet Union's recent achievement of orbiting the world's first artificial satellite. Although PSAC members ultimately decided visual reconnaissance (i.e., close-up photographs of the lunar surface) was the best means to achieve this goal, they did briefly consider (but rejected) the idea of landing and exploding an atomic bomb on the moon. (This paper is based on research conducted under a NASA-JPL contract.)

  7. Focus: Reaching for the Moon

    NASA Astrophysics Data System (ADS)

    Baldwin, Emily; Chadha, Kulvinder Singh

    2008-05-01

    The man in the moon. Blue moon. Heavy bombardment era. Black moon. Mechanics of the moon. Perigee/apogee. Blood moon. Harvest moon. Destination moon. Wet moon. Moon Britannia. Moon rocks come down to Earth. Fairy moon.

  8. The transition from complex crater to peak-ring basin on the Moon: New observations from the Lunar Orbiter Laser Altimeter (LOLA) instrument

    NASA Astrophysics Data System (ADS)

    Baker, David M. H.; Head, James W.; Fassett, Caleb I.; Kadish, Seth J.; Smith, Dave E.; Zuber, Maria T.; Neumann, Gregory A.

    2011-08-01

    Impact craters on planetary bodies transition with increasing size from simple, to complex, to peak-ring basins and finally to multi-ring basins. Important to understanding the relationship between complex craters with central peaks and multi-ring basins is the analysis of protobasins (exhibiting a rim crest and interior ring plus a central peak) and peak-ring basins (exhibiting a rim crest and an interior ring). New data have permitted improved portrayal and classification of these transitional features on the Moon. We used new 128 pixel/degree gridded topographic data from the Lunar Orbiter Laser Altimeter (LOLA) instrument onboard the Lunar Reconnaissance Orbiter, combined with image mosaics, to conduct a survey of craters >50 km in diameter on the Moon and to update the existing catalogs of lunar peak-ring basins and protobasins. Our updated catalog includes 17 peak-ring basins (rim-crest diameters range from 207 km to 582 km, geometric mean = 343 km) and 3 protobasins (137-170 km, geometric mean = 157 km). Several basins inferred to be multi-ring basins in prior studies (Apollo, Moscoviense, Grimaldi, Freundlich-Sharonov, Coulomb-Sarton, and Korolev) are now classified as peak-ring basins due to their similarities with lunar peak-ring basin morphologies and absence of definitive topographic ring structures greater than two in number. We also include in our catalog 23 craters exhibiting small ring-like clusters of peaks (50-205 km, geometric mean = 81 km); one (Humboldt) exhibits a rim-crest diameter and an interior morphology that may be uniquely transitional to the process of forming peak rings. A power-law fit to ring diameters ( Dring) and rim-crest diameters ( Dr) of peak-ring basins on the Moon [ Dring = 0.14 ± 0.10( Dr) 1.21±0.13] reveals a trend that is very similar to a power-law fit to peak-ring basin diameters on Mercury [ Dring = 0.25 ± 0.14( Drim) 1.13±0.10] [Baker, D.M.H. et al. [2011]. Planet. Space Sci., in press]. Plots of ring

  9. Tidally Heated ExoMoons (THEM)

    NASA Astrophysics Data System (ADS)

    Dobos, V.

    2014-04-01

    More than a thousand exoplanets have been identified to date (Schneider 2014); however, moons orbiting exoplanets have not been discovered, yet. Nevertheless, it is probable that exomoons will be detected in the near future if they are not much more rare in exoplanetary systems than they are in the Solar System (Heller & Barnes 2013, Peters & Turner 2013, Kaltenegger 2010). For this reason it is important to begin to develop basic theoretical models of exomoons in advance of the first detections. Habitability is a particularly important aspect, since life might well develop on a non-planetary body if it has suitable characteristics and environmentals. Tidal forces produced by the planet which the moon orbits can induce friction inside the satellite that will have a warming effect (Peale et al. 1979). In the Solar System there are several examples for moons that have significant heating due to tidal forces. On exomoons that are too far from their central star to have habitable surface temperatures due to radiative heating, it is possible that warmth area of the surface produced by tidal heating could allow the emergence of life (Scharf 2006). This investigation focuses on tidal heating, studying the surface temperature of hypothetical exomoons for different orbital and interior parameters of the body. The aim of our research is to describe the conditions that allow the existence of water reservoirs in the liquid phase state on or near the surface. We modified and extended the public code of Heller & Barnes (2013) for the purposes of this investigation. References Heller, R., Barnes, R. 2013 Exomoon Habitability Constrained by Illumination and Tidal Heating, Astrobiology 13, 18 Kaltenegger, L. 2010 Characterizing habitable exomoons, The Astrophysical Journal Letters 712, 125 Peale, S. J., Cassen, P., Reynolds, R. T. 1979 Melting of Io by Tidal Dissipation, Science 203, 892 Peters, M. A., Turner, E. L. 2013 On the direct imaging of tidally heated exomoons, The

  10. Lunar magnetism, space weathering, and icy satellite interiors

    NASA Astrophysics Data System (ADS)

    Hemingway, Douglas

    An enduring mystery since Apollo is that, in spite of the Moon's lack of a global magnetic field, the surface is nevertheless dotted with regional magnetic fields strong enough to be detected from orbit. Did the Moon once have an intrinsic global field that magnetized parts of the crust but has since decayed away? This is a question of fundamental importance to understanding the formation and evolution of solid planetary bodies, and yet it remains unanswered due in part to limitations in our knowledge of these crustal magnetic anomalies. Adding to the puzzle, many of these magnetic anomalies are accompanied by enigmatic optical features, known as swirls, which may hold the key to understanding "space weathering"---a process by which airless bodies change color over time due to exposure to solar wind and micrometeoroids. Here we show both that swirl morphology provides information about the structure of the underlying magnetic sources, and that the color of the lunar surface varies systematically with latitude in a way that allows us to distinguish between the effects of solar wind ion and micrometeoroid bombardment, addressing a decades-old problem in remote sensing, and aiding in the interpretation of the spectra of airless bodies throughout the solar system. The remarkable diversity of the outer solar system's satellites provides important clues about the formation and evolution of the solar system. Many of the satellites have surprisingly young surfaces, owing in some cases to on-going geologic activity. Moreover, the existence of subsurface oceans within some of the satellites raises the intriguing possibility of extant habitable environments in the outer solar system. Determining the properties of their ice shells and the structures of their deep interiors places fundamental constraints on how the icy satellites formed and evolved, and on what governs their behavior today. Using gravity and topography data from Cassini, we develop analytical models showing

  11. Improvement of the ephemerides of the Martian moons from the amelioration of the Martian spacecraft orbits: Investigating a data-arc splitting method

    NASA Astrophysics Data System (ADS)

    Kudryashova, M.; Rosenblatt, P.; Lainey, V.; Le Maistre, S.; Marty, J. C.

    2012-04-01

    Phobos and Deimos ephemerides have been recently improved, using numerical modeling of their motion and astrometric observations of their positions from images taken by both Earth-based telescopes and cameras onboard spacecraft. In order to compute moon ephemerides from the spacecraft images, the spacecraft position on the orbit has to be known as precisely as possible. We propose to investigate a data-arc splitting method, consisting of computing precise orbit of spacecraft using suitable data-arcs encompassing each astrometric observations instead of successive data-arcs disregarding the occurrence of these observations as usually done for spacecraft navigation orbits. In this study, we test our method on Phobos' photographic observations taken by the Mars Express (MEX) Super Resolution Camera (SRC). We especially investigate the impact of the data-arc length (2, 4 or 10 days) and of the position of photographic observations inside the data-arc (from near the starting epoch to near the ending epoch of the data-arc) on Phobos' positions. We first compute new MEX orbits from fitting a dynamical model of MEX motion to Doppler and ranging tracking data for these different data-arcs (using the GINS software developed by the French space agency CNES and further adapted at Royal Observatory of Belgium for planetary geodesy applications). Then, we compute the positions of Phobos as seen from our new MEX orbits and compare it with the positions obtained from astrometric observations in order to assess the improvement expected from our method. Once validated on the MEX data, we plan to apply our method to older spacecraft data (Mariner-9, Viking 1-2, …) in order to provide better spacecraft positions to derive better Phobos' positions. These new positions will then be used to re-compute a better Phobos' ephemeris. In fine, the goal of this new ephemeris is to improve the knowledge of several geophysical parameters of the Martian system (such as the secular acceleration

  12. Materials and Surface Processes at Gale Crater and the Moons of Mars Derived from High Spatial and Spectral Resolution Orbital Datasets

    NASA Astrophysics Data System (ADS)

    Fraeman, Abigail Ann

    This thesis is a collection of studies that use orbital remote sensing data to investigate the composition and geologic histories of Mars' moons, Phobos and Deimos, and Mt. Sharp, the destination for the Curiosity Mars rover. A final chapter focuses on Curiosity data and terrestrial analog studies to supplement orbital predictions about Mt. Sharp. Disk-resolved hyperspectral observations of Phobos acquired at a range of lighting and viewing geometries are fit with a Hapke photometric function to solve for the single particle phase function and single scattering albedos of Phobos and also disk-resolved hyperspectral observations of Deimos. Fe2+ electronic absorptions diagnostic of olivine and pyroxene are not detected. A broad absorption centered on 0.65 microm within the red spectral units of both moons is seen, and this feature is also evident in telescopic, Pathfinder, and Phobos-2 observations of Phobos. A 2.8 μm metal-OH combination absorption on both moons is also detected, and this absorption is shallower in the Phobos blue unit than in the Phobos red unit and Deimos. The strength, position, and shape of both absorptions are similar to features seen on low-albedo primitive asteroids. Two end-member hypotheses could explain these spectral features: the presence of highly desiccated Fe-phyllosilicate minerals indigenous to the bodies, or Rayleigh scattering and absorption of small iron particles formed by exogenic space weathering processing, coupled with implantation of H from solar wind. Phobos' and Deimos' low reflectances, lack of mafic absorption features, and red spectral slopes are incompatible with even highly space weathered chondritic or basaltic compositions. These results, coupled with similarities to laboratory spectra of Tagish Lake (possible D-type asteroid analog) and CM carbonaceous chondrite meteorites, show that Phobos and Deimos have primitive compositions. If the moons formed in situ rather than by capture of primitive bodies, primitive

  13. M2 ocean tide parameters and the deceleration of the moon's mean longitude from satellite orbit data

    NASA Technical Reports Server (NTRS)

    Felsentreger, T. L.; Marsh, J. G.; Williamson, R. G.

    1979-01-01

    An estimation is made of the principal long-period spherical harmonic parameters in the representation of the M2 ocean tide from the orbital histories of the three satellites 1967-92A, Starlette, and GEOS 3. The data used are primarily the evolution of the orbital inclinations of the satellites in conjunction with the longitude of the ascending node from GEOS 3. Analysis procedure and analytic formulation, as well as ocean tidal parameter estimation and deceleration of the lunar mean longitude are outlined. The credibility of the M2 ocean tide solution is further enhanced by the close accord between the computed value for the deceleration of the lunar mean longitude and other recently reported estimates. It is evident from the results presented that studies of close earth satellite orbits are able to provide important information about the tidal forces acting on the earth.

  14. Interactive Visualization of Parking Orbits Around the Moon: An X3D Application for a NASA Lunar Mission Study

    NASA Technical Reports Server (NTRS)

    Murphy, Douglas G.; Qu, Min; Salas, Andrea O.

    2006-01-01

    The NASA Integrated Modeling and Simulation (IM&S) project aims to develop a collaborative engineering system to include distributed analysis, integrated tools, and web-enabled graphics. Engineers on the IM&S team were tasked with applying IM&S capabilities to an orbital mechanics analysis for a lunar mission study. An interactive lunar globe was created to show 7 landing sites, contour lines depicting the energy required to reach a given site, and the optimal lunar orbit orientation to meet the mission constraints. Activation of the lunar globe rotation shows the change of the angle between the landing site latitude and the orbit plane. A heads-up-display was used to embed straightforward interface elements.

  15. GLGM-3: A degree-150 lunar gravity model from the historical tracking data of NASA Moon orbiters

    NASA Astrophysics Data System (ADS)

    Mazarico, E.; Lemoine, F. G.; Han, Shin-Chan; Smith, D. E.

    2010-05-01

    In preparation for the radio science experiment of the Lunar Reconnaissance Orbiter (LRO) mission, we analyzed the available radio tracking data of previous NASA lunar orbiters. Our goal was to use these historical observations in combination with the new low-altitude data to be obtained by LRO. We performed Precision Orbit Determination on trajectory arcs from Lunar Orbiter 1 in 1966 to Lunar Prospector in 1998, using the GEODYN II program developed at NASA Goddard Space Flight Center. We then created a set of normal equations and solved for the coefficients of a spherical harmonics expansion of the lunar gravity potential up to degree and order 150. The GLGM-3 solution obtained with a global Kaula constraint (2.5 × 10-4l-2) shows good agreement with model LP150Q from the Jet Propulsion Laboratory, especially over the nearside. The levels of data fit with both gravity models are very similar (Doppler RMS of ˜0.2 and ˜1-2 mm/s in the nominal and extended phases, respectively). Orbit overlaps and uncertainties estimated from the covariance matrix also agree well. GLGM-3 shows better correlation with lunar topography and admittance over the nearside at high degrees of expansion (l > 100), particularly near the poles. We also present three companion solutions, obtained with the same data set but using alternate inversion strategies that modify the power law constraint and expectation of the individual spherical harmonics coefficients. We give a detailed discussion of the performance of this family of gravity field solutions in terms of observation fit, orbit quality, and geophysical consistency.

  16. GLGM-3: A Degree-ISO Lunar Gravity Model from the Historical Tracking Data of NASA Moon Orbiters

    NASA Technical Reports Server (NTRS)

    Mazarico, E.; Lemoine, F. G.; Han, Shin-Chan; Smith, D. E.

    2010-01-01

    In preparation for the radio science experiment of the Lunar Reconnaissance Orbiter (LRO) mission, we analyzed the available radio tracking data of previous NASA lunar orbiters. Our goal was to use these historical observations in combination with the new low-altitude data to be obtained by LRO. We performed Precision Orbit Determination on trajectory arcs from Lunar Orbiter 1 in 1966 to Lunar Prospector in 1998, using the GEODYN II program developed at NASA Goddard Space Flight Center. We then created a set of normal equations and solved for the coefficients of a spherical harmonics expansion of the lunar gravity potential up to degree and order 150. The GLGM-3 solution obtained with a global Kaula constraint (2.5 x 10(exp -4)/sq l) shows good agreement with model LP150Q from the Jet Propulsion Laboratory, especially over the nearside. The levels of data fit with both gravity models are very similar (Doppler RMS of approx.0.2 and approx. 1-2 mm/s in the nominal and extended phases, respectiVely). Orbit overlaps and uncertainties estimated from the covariance matrix also agree well. GLGM-3 shows better correlation with lunar topography and admittance over the nearside at high degrees of expansion (l > 100), particularly near the poles. We also present three companion solutions, obtained with the same data set but using alternate inversion strategies that modify the power law constraint and expectation of the individual spherical harmonics coefficients. We give a detailed discussion of the performance of this family of gravity field solutions in terms of observation fit, orbit quality, and geophysical consistency.

  17. Stability of Frozen Orbits Around Europa

    NASA Astrophysics Data System (ADS)

    Cardoso Dos Santos, Josué; Vilhena de Moraes, R.; Carvalho, J. S.

    2013-05-01

    Abstract (2,250 Maximum Characters): A planetary satellite of interest at the present moment for the scientific community is Europa, one of the four largest moons of Jupiter. There are some missions planned to visit Europa in the next years, for example, Jupiter Europa Orbiter (JEO, NASA) and Jupiter IcyMoon Explorer (JUICE, ESA). In this work we are formulating theories and constructing computer programs to be used in the design of aerospace tasks as regards the stability of artificial satellite orbits around planetary satellites. The studies are related to translational motion of orbits around planetary satellites considering polygenic perturbations due to forces, such as the nonspherical shape of the central body and the perturbation of the third body. The equations of motion will be developed in closed form to avoid expansions in eccentricity and inclination. For a description of canonical formalism are used the Delaunay canonical variables. The canonical set of equations, which are nonlinear differential equations, will be used to study the stability of orbits around Europa. We will use a simplified dynamic model, which considers the effects caused by non-uniform distribution of mass of Europa (J2, J3 and C22) and the gravitational attraction of Jupiter. Emphasis will be given to the case of frozen orbits, defined as having almost constant values of eccentricity, inclination, and argument of pericentre. An approach will be used to search for frozen orbits around planetary satellites and study their stability by applying a process of normalization of Hamiltonian. Acknowledges: FAPESP

  18. Radar-Sounding of Icy Mantles and Comets Using Natural Radio Noise

    NASA Astrophysics Data System (ADS)

    Winebrenner, D. P.; Sahr, J. D.

    2011-10-01

    Radar-sounding of ice sheets on Earth yields crucial information on ice history and dynamics, including discoveries of subglacial lakes beneath 3-4 km of ice [1]. Mars Express and the Mars Reconnaissance Orbiter (MRO) have now demonstrated the corresponding power of orbital radar sounding for planetary exploration, in particular by imaging structures within and beneath kilometers of Martian water ice [2-4]. Based on this experience, a sophisticated orbital radar sounder is planned for a flagship mission to Europa, with the aim of imaging stratigraphy, faults, diapirs and other geological structure in the upper few kilometers of the water-ice mantle there, and possibly even detecting the upper surface of the (likely) underlying ocean [5]. Recent modeling of the formation and evolution of volatilerich bodies suggests that oceans or lakes of liquid water occur beneath water-ice mantles in a surprising variety of places, including Ceres in the outer asteroid belt [6], 3 of the 4 Galilean moons of Jupiter as well as Enceladus and Titan in the Saturnian system [7], and possibly even Pluto [8]. Thus there is now a wide scope for low-cost missions to bodies of exceptional interest, and for radar sounding of icy mantles to image near-surface structural geology related to underlying water (whether past or present).

  19. Considerations for a Radar System to Detect an Ocean Underneath the Icy Shell of Europa

    NASA Technical Reports Server (NTRS)

    Markus, Thorsten; Gogineni, Prasad; Green, James; Cooper, John; Fung, Shing; Taylor, William; Benson, Robert; Reinisch, Bodo; Song, Paul

    2004-01-01

    The detection of an ocean underneath Europa is one of the primary objectives of the Jupiter Icy Moons Orbiter (JIMO) mission. An orbiting surface penetrating radar has the potential of providing that measurement thus yielding information regarding the possibility of life support on Europa. Radars in the MHz range have successfully monitored the kilometer-deep ice shelves of Greenland and Antarctica, including the detection of Lake Vostok (and others) below an ice sheet thickness of about 4 km. The performance of a radar system orbiting Europa will be subject to several potential complications and unknowns. Besides ionospheric dispersion and the actual depth of the ocean, which is estimated between 2 and 30 km, major unknowns affecting radar performance are the temperature profile, the amount of salt and other impurities within the ice crust as well as the surface roughness. These impurities can in part be produced at the highly irradiated surface by magnetospheric interactions and transported downward into the ice crust by geologic processes. The ionospheric interference must also be modeled from effects of these interactions on production of the thin neutral atmosphere and subsequent ionization of the neutrals. We investigated these uncertainties through radar simulations using different surface and ice characteristics over a frequency range from 10 to 50 MHz. The talk will present results from these simulations discussing potential limitations.

  20. Photon-counting lidars for contiguous high resolution topographic mapping of planets and moons

    NASA Astrophysics Data System (ADS)

    Degnan, John J.

    2007-08-01

    moon Europa, and the Saturnian moons, Titan and Enceladus. A recently completed study for NASA's Jupiter Icy Moons Orbiter (JIMO) mission concluded that the three primary Jovian moons (Ganymede, Callisto, and Europa) could be contiguously and globally mapped, at few meter horizontal resolutions, by a photon-counting lidar in a matter of months from orbital altitudes of 100 km. Work is also underway to include a technical demonstration of a photon-counting lidar ("Swath Mapper") on NASA's ICESat-II mission, which is scheduled for a 2011 launch into a 600 km orbit. Swath Mapper would use a single low energy, high repetition rate laser (nominally 1 mJ@ 10 kHz = 10W) to measure surface topography along 16 uniformly spaced ground tracks spread over roughly 2.1 km.

  1. Impact origin of the Moon

    SciTech Connect

    Slattery, W.L.

    1998-12-31

    A few years after the Apollo flights to the Moon, it became clear that all of the existing theories on the origin of the Moon would not satisfy the growing body of constraints which appeared with the data gathered by the Apollo flights. About the same time, researchers began to realize that the inner (terrestrial) planets were not born quietly -- all had evidences of impacts on their surfaces. This fact reinforced the idea that the planets had formed by the accumulation of planetesimals. Since the Earth`s moon is unique among the terrestrial planets, a few researchers realized that perhaps the Moon originated in a singular event; an event that was quite probable, but not so probable that one would expect all the terrestrial planets to have a large moon. And thus was born the idea that a giant impact formed the Moon. Impacts would be common in the early solar system; perhaps a really large impact of two almost fully formed planets of disparate sizes would lead to material orbiting the proto-earth, a proto-moon. This idea remained to be tested. Using a relatively new, but robust, method of doing the hydrodynamics of the collision (Smoothed-Particle Hydrodynamics), the author and his colleagues (W. Benz, Univ. of Arizona, and A.G.W. Cameron, Harvard College Obs.) did a large number of collision simulations on a supercomputer. The author found two major scenarios which would result in the formation of the Moon. The first was direct formation; a moon-sized object is boosted into orbit by gravitational torques. The second is when the orbiting material forms a disk, which, with subsequent evolution can form the Moon. In either case the physical and chemical properties of the newly formed Moon would very neatly satisfy the physical and chemical constraints of the current Moon. Also, in both scenarios the surface of the Earth would be quite hot after the collision. This aspect remains to be explored.

  2. Characterizing the Moon's radiation environment

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2013-05-01

    The radiation environment near the Moon could be damaging to humans and electronics on future missions. To characterize this potentially hazardous environment, the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) on board the Lunar Reconnaissance Orbiter mission, which orbits at 50 kilometers above the Moon's surface, measures the radiation that would be absorbed by either electronic parts or human tissue behind the shielding of a spacecraft.

  3. The Chemist's Moon

    ERIC Educational Resources Information Center

    Arnold, James R.

    1973-01-01

    Summarizes chemical information about the lunar surface on the basis of experiments performed in orbit and analyses of lunar soil and rocks. Indicates that the Apollo program completes chemical mapping of about 20 percent of the Moon with 80 percent remaining to be solved in the future. (CC)

  4. Morphometric analysis of small-scale lobate scarps on the Moon using data from the Lunar Reconnaissance Orbiter

    NASA Astrophysics Data System (ADS)

    Banks, M. E.; Watters, T. R.; Robinson, M. S.; Tornabene, L. L.; Tran, T.; Ojha, L.; Williams, N. R.

    2012-03-01

    Prior to Lunar Reconnaissance Orbiter (LRO), the morphology and dimensions of only a limited number of lobate scarps, all located near the equator (within 21°), had been characterized. Topography derived from LRO Camera stereo images and Lunar Orbiter Laser Altimeter (LOLA) ranging is used to measure the relief and analyze the morphology of previously known and newly detected low and high latitude lobate scarps. The asymmetric profiles and maximum slopes on scarp faces (˜5° to 29°) of lunar lobate scarps are similar to those of lobate scarps observed on Mars and Mercury. Scarp lengths range from ˜0.6 to 21.6 km (mean = ˜6.0 km, median = ˜4.4 km, n = 79), and measured relief ranges from ˜5 to 150 m (mean = ˜35 m, median = ˜20 m, n = 26). Assuming a range of 20° to 40° for the fault plane dip, estimated lower limits for the horizontal shortening (S) expressed by the lobate scarp thrust faults range from ˜10 to 410 m. The range in S estimated for the lunar scarps is roughly an order of magnitude lower than estimates of S for lobate scarp thrust faults on Mars and Mercury. The relatively small range of S estimated for the growing number of well-characterized lunar scarps is consistent with a small amount of global contraction.

  5. M2 ocean tide parameters and the deceleration of the moon's mean longitude from satellite orbit data

    NASA Technical Reports Server (NTRS)

    Felsentreger, T. L.; Marsh, J. G.; Williamson, R. G.

    1978-01-01

    An estimation was made of the principal long period spherical harmonic parameters in the representation for the M sub 2 ocean tide from the orbital histories of three satellites - 1967-92A (TRANSIT), Starlette, and GEOS-3. The data used were primarily the evolution of the orbital inclinations of the satellites, with the addition of the longitude of the ascending node from GEOS-3. The results are: (1) C sub 22 superscript + = 3.42 plus or minus 0.24 cm; (2) sub 42 superscript + = 0.97 plus or minus 0.12 cm; (3) epsilon subscript 22 superscript + = 325 D.5 plus or minus 3.D9; (4) epsilon subscript 42 superscript + = 42 = 124D.0 plus or minus 6 D.9. These values agree quite well with recent numerical models and another recent determination from satellite data. The M sub 2 parameters obtained here infer an N of -25 plus or minus 3 arc seconds/century squared, in good agreement with other investigators. The range of current determinations of N is from -24.6 to 27.2 arc second/century squared.

  6. Geosciences at the Galilean Moons With the Multiple Instrument Distributed Aperture Sensor (MIDAS)

    NASA Astrophysics Data System (ADS)

    Delory, G. T.; Lipps, J. H.; de Pater, I.; Manga, M.; Rieboldt, S.; Dalton, J. B.; Bierhaus, E. B.; Pitman, J.; Duncan, A.

    2004-05-01

    Geosciences at the Galilean Moons With the Multiple Instrument Distributed Aperture Sensor (MIDAS) The Voyager and Galileo missions have revealed the Galilean Icy Moons and Io to be dynamic worlds, possessing possible subsurface oceans, magnetism, spectacular volcanic activity, and potentially extinct or extant life. While our knowledge of the Galilean moons has indeed been revolutionized by the missions conducted to date, modest spectral and spatial resolution data sets achieved on Galileo due to high gain antenna problems, difficulties in coordinated instrument operations, and inherent instrument design limits leave many unanswered questions: What is the state and distribution of ice and liquid water on Europa? What processes control the distribution and composition of the non-icy material on the surface? What is the extent of tectonic and volcanic activity? These and other questions have an important bearing not only on our knowledge of the geology and origin of these moons, but are also highly relevant to an assessment of their past or present habitability. A limited number of flybys have yielded km-scale and some m-scale images that provide some context for these and other questions, but it is unlikely we will be able to apply all of these lessons learned to the numerous features that are almost certain to exist at or below the current detection limits. To advance our understanding of these moons to the next step, global coverage at spatial scales ranging from ~cm to m combined with simultaneous spectral measurements with ~nm precision over long timescales are required. Here we describe how these science objectives can be fulfilled on the Jupiter Icy Moons Orbiter (JIMO) mission by the Multiple Instrument Distributed Aperture Sensor (MIDAS). MIDAS is a unique distributed aperture imaging spectrometer capable of high spectral and spatial resolutions using less mass, volume, and power than systems with similar capabilities, and is compatible with the Prometheus

  7. The origin of the moon.

    PubMed

    Boss, A P

    1986-01-24

    The origin of the moon is considered within the theory of formation of the terrestrial planets by accumulation of planetesimals. The theory predicts the occurrence of giant impacts, suggesting that the moon formed after a roughly Mars-sized body impacted on the protoearth. The impact blasted portions of the protoearth and the impacting body into geocentric orbit, forming a prelunar disk from which the moon later accreted. Although other mechanisms for formation of the moon appear to be dynamically impossible or implausible, fundamental questions must be answered before a giant impact origin can be considered both possible and probable. PMID:17735007

  8. Jupiter's Moons: Family Portrait

    NASA Technical Reports Server (NTRS)

    2007-01-01

    This montage shows the best views of Jupiter's four large and diverse 'Galilean' satellites as seen by the Long Range Reconnaissance Imager (LORRI) on the New Horizons spacecraft during its flyby of Jupiter in late February 2007. The four moons are, from left to right: Io, Europa, Ganymede and Callisto. The images have been scaled to represent the true relative sizes of the four moons and are arranged in their order from Jupiter.

    Io, 3,640 kilometers (2,260 miles) in diameter, was imaged at 03:50 Universal Time on February 28 from a range of 2.7 million kilometers (1.7 million miles). The original image scale was 13 kilometers per pixel, and the image is centered at Io coordinates 6 degrees south, 22 degrees west. Io is notable for its active volcanism, which New Horizons has studied extensively.

    Europa, 3,120 kilometers (1,938 miles) in diameter, was imaged at 01:28 Universal Time on February 28 from a range of 3 million kilometers (1.8 million miles). The original image scale was 15 kilometers per pixel, and the image is centered at Europa coordinates 6 degrees south, 347 degrees west. Europa's smooth, icy surface likely conceals an ocean of liquid water. New Horizons obtained data on Europa's surface composition and imaged subtle surface features, and analysis of these data may provide new information about the ocean and the icy shell that covers it.

    New Horizons spied Ganymede, 5,262 kilometers (3,268 miles) in diameter, at 10:01 Universal Time on February 27 from 3.5 million kilometers (2.2 million miles) away. The original scale was 17 kilometers per pixel, and the image is centered at Ganymede coordinates 6 degrees south, 38 degrees west. Ganymede, the largest moon in the solar system, has a dirty ice surface cut by fractures and peppered by impact craters. New Horizons' infrared observations may provide insight into the composition of the moon's surface and interior.

    Callisto, 4,820 kilometers (2,995 miles) in diameter, was imaged

  9. Trajectory determination support and analysis for ISEE-3 from halo orbit to escape from the earth/moon system

    NASA Technical Reports Server (NTRS)

    Joyce, J. B.; Schanzle, A. F.

    1984-01-01

    The analyses performed in altering the ISEE-3 spacecraft path from a liberation point to a helicocentric orbit for intercepting the Giacobini-Zimmer cometary tail are reviewed. The initial calculations considered the expected accuracy, the best temporal lengths to be used for the calculations and the maneuver points. The early maneuvers were also constrained to a maximum number of crossings of the terrestrial magnetotail for data collection purposes. Three earth-based tracking stations trajectory data collection schedules were projected, and programs were prepared for comparing tracking data with predictions. Delta- V maneuvers were set for perigee locations in order to conserve fuel. A 21-day span was selected for tracking, expect during maneuver periods. Accuracies of 0.1-10 km and 0.3-2.0 cm/sec were obtained.

  10. Orbiters for Callisto and Titan - the Affordable Options

    NASA Astrophysics Data System (ADS)

    Wenkert, Daniel; Elliott, John O.

    2014-11-01

    Low cost missions to orbit the icy satellites of outer planets are possible. Recent studies by the “A Team” at the Jet Propulsion Laboratory have investigated possible configurations and costs of Callisto and Titan orbiters. The Callisto study was done as a demonstration that a scientifically valuable icy moon orbiter could be accomplished within the current Discovery mission cost cap. A solar-powered concept was defined, whose cost was estimated to be below the cost cap, including full reserves. The mission would operate from a low circular orbit (100 km altitude); would carry a medium-resolution visible imaging camera, a laser altimeter, and a magnetometer; and would use Ka-band tracking for gravity studies. The Titan orbiter study was done as part of a set of studies focused on decreasing the costs of several different types of Titan missions. The cost estimated for the orbiter was below the most recent New Frontiers cost cap. The mission would operate from a high circular orbit (1500 km altitude) to reduce atmospheric drag and would carry a medium-resolution infrared imaging camera and a mass spectrometer. Callisto’s distance from Jupiter allows a lower cost orbiter than one for Ganymede or Europa. At Callisto’s distance, the radiation environment is drastically more benign, decreasing the need for electronics hardening and/or radiation shielding and its associated mass. Being further from Jupiter’s gravity well decreases the fuel needed for capture into a Jupiter orbit appropriate for an eventual capture by Callisto. Finally, its lower mass allows Callisto orbit insertion with less fuel than that needed for a similar maneuver at Ganymede. Although costing for the Titan orbiter mission assumed a normal propulsive capture into Saturn orbit, the great extent of Titan’s relatively benign atmosphere should make it possible to aerocapture directly into Titan orbit from interplanetary cruise, at potentially lower cost.

  11. Earth - Moon Conjunction

    NASA Technical Reports Server (NTRS)

    1992-01-01

    On December 16, 1992, 8 days after its encounter with Earth, the Galileo spacecraft looked back from a distance of about 6.2 million kilometers (3.9 million miles) to capture this remarkable view of the Moon in orbit about Earth. The composite photograph was constructed from images taken through visible (violet, red) and near-infrared (1.0-micron) filters. The Moon is in the foreground; its orbital path is from left to right. Brightly colored Earth contrasts strongly with the Moon, which reacts only about one-third as much sunlight as our world. To improve the visibility of both bodies, contrast and color have been computer enhanced. At the bottom of Earth's disk, Antarctica is visible through clouds. The Moon's far side can also be seen. The shadowy indentation in the Moon's dawn terminator--the boundary between its dark and lit sides--is the South Pole-Aitken Basin, one of the largest and oldest lunar impact features. This feature was studied extensively by Galileo during the first Earth flyby in December 1990.

  12. LRO Exposes the Moon's Complex, Turbulent Youth

    NASA Video Gallery

    Using the Lunar Reconnaissance Orbiter’s Lunar Orbiter Laser Altimeter (LOLA), NASA scientists have created the first-ever comprehensive catalog of large craters on the moon. In this animation, lun...

  13. THE EVOLUTION OF CIRCUMPLANETARY DISKS AROUND PLANETS IN WIDE ORBITS: IMPLICATIONS FOR FORMATION THEORY, OBSERVATIONS, AND MOON SYSTEMS

    SciTech Connect

    Shabram, Megan; Boley, Aaron C.

    2013-04-10

    Using radiation hydrodynamics simulations, we explore the evolution of circumplanetary disks around wide-orbit proto-gas giants. At large distances from the star ({approx}100 AU), gravitational instability followed by disk fragmentation can form low-mass substellar companions (massive gas giants and/or brown dwarfs) that are likely to host large disks. We examine the initial evolution of these subdisks and their role in regulating the growth of their substellar companions, as well as explore consequences of their interactions with circumstellar material. We find that subdisks that form in the context of GIs evolve quickly from a very massive state. Long-term accretion rates from the subdisk onto the proto-gas giant reach {approx}0.3 Jupiter masses kyr{sup -1}. We also find consistency with previous simulations, demonstrating that subdisks are truncated at {approx}1/3 of the companion's Hill radius and are thick, with (h/r) of {approx}> 0.2. The thickness of subdisks draws to question the use of thin-disk approximations for understanding the behavior of subdisks, and the morphology of subdisks has implications for the formation and extent of satellite systems. These subdisks create heating events in otherwise cold regions of the circumstellar disk and serve as planet formation beacons that can be detected by instruments such as ALMA.

  14. Space missions orbits around small worlds

    NASA Astrophysics Data System (ADS)

    Cardoso dos Santos, Josué; dos Santos Carvalho, Jean Paulo; Vilhena de Moraes, Rodolpho; Bertachini de Almeida Prado, Antônio Fernando

    2015-08-01

    Space missions under study to visit icy moons and small worlds in our solar system will requires orbits with low-altitude and high inclinations. These orbits provides a better coverage to map the surface and to analyse the gravitational and magnetic fields. In this context, obtain these orbits has become important in planning of these missions. Celestial bodies like Haumea, Europa, Ganymede, Callisto, Enceladus, Titan and Triton are among the objects under study study to receive missions in a near future. In order to obtain low-altitude and high inclined orbits for future exploration of these bodies, this work aims to present an analytical study to describe and evaluate gravitational disturbances over a spacecraft's orbit around a minor body. An analytical model for the third-body perturbation is presented. Perturbations due to the non-sphericity of the minor body are considered. The effects on spacecraft's orbital elements are analyzed to provide the the more useful and desired orbits. The dynamic of these orbits is explored by numerical simulations. The results present good accordance with the literature.

  15. Spectral properties of icy satellites

    NASA Astrophysics Data System (ADS)

    Stephan, Katrin; Jaumann, Ralf; Wagner, Roland; Clark, Roger; Cruikshank, Dale; Brown, Robert; Roatsch, Thomas; Buratti, Bonnie; Matson, Dennis; Dalle Ore, Cristina; Filacchione, Gianrico; Capaccioni, Fabrizio; Nicholson, Phil; Baines, Kevin; Sotin, Christoph

    2015-08-01

    Since 2004 Cassini is orbiting the Saturnian system with its instruments investigating the chemical and physical properties of Saturn ‘s atmosphere, its magnetosphere, its numerous satellites and rings. The VIMS instrument onboard Cassini enables not only to identify the Saturn satellites’ compositional units but also to map their distribution across the surfaces, to relate their location and extension to specific geological and/or geomorphological surface features and to characterize surface alterations induced by the space environment. Although, the VIMS spectra of the Saturnian satellites’ surfaces are dominated by H2O-ice, its distribution and physical characteristics differ distinctly from one satellite to the other. Global hemispherical differences are mostly related to the satellite’s orbital position within the Saturnian system, i.e. the distance to Saturn and its E ring, with particles originating from Saturn’s magnetosphere and/or the ice grains coming from the E ring impacting their surfaces. Often, these hemispherical differences are characterized by a dark non-icy contaminant more concentrated on their trailing hemispheres, while the more water ice-rich leading hemispheres appear covered by fresh material ejected by an impact event and/or by impacting E-ring particles. Tethys, however, situated closer to Enceladus and the E ring and deeper within Saturn’s magnetosphere, shows a more complex pattern. Compositional changes on a regional and local scale could be identified and related to the geological processes, i.e. impact cratering, tectonics, and erosion. Particularly, young impact craters and tectonic features reveal clean H2O ice of relatively large grain size while the “fresh” (unaltered) surface material offers a unique view into the crustal properties and evolution of its satellite. Whereas, prominent graben systems on Dione and Rhea are characterized by a pronounced ice signature - Ithaca Chasma on Tethys is barely recognizable

  16. N-BODY SIMULATIONS OF SATELLITE FORMATION AROUND GIANT PLANETS: ORIGIN OF ORBITAL CONFIGURATION OF THE GALILEAN MOONS

    SciTech Connect

    Ogihara, Masahiro; Ida, Shigeru E-mail: ida@geo.titech.ac.jp

    2012-07-01

    As the number of discovered extrasolar planets has been increasing, diversity of planetary systems requires studies of new formation scenarios. It is important to study satellite formation in circumplanetary disks, which is often viewed as analogous to formation of rocky planets in protoplanetary disks. We investigated satellite formation from satellitesimals around giant planets through N-body simulations that include gravitational interactions with a circumplanetary gas disk. Our main aim is to reproduce the observable properties of the Galilean satellites around Jupiter through numerical simulations, as previous N-body simulations have not explained the origin of the resonant configuration. We performed accretion simulations based on the work of Sasaki et al., in which an inner cavity is added to the model of Canup and Ward. We found that several satellites are formed and captured in mutual mean motion resonances outside the disk inner edge and are stable after rapid disk gas dissipation, which explains the characteristics of the Galilean satellites. In addition, owing to the existence of the disk edge, a radial compositional gradient of the Galilean satellites can also be reproduced. An additional objective of this study is to discuss orbital properties of formed satellites for a wide range of conditions by considering large uncertainties in model parameters. Through numerical experiments and semianalytical arguments, we determined that if the inner edge of a disk is introduced, a Galilean-like configuration in which several satellites are captured into a 2:1 resonance outside the disk inner cavity is almost universal. In fact, such a configuration is produced even for a massive disk {approx}> 10{sup 4} g cm{sup -2} and rapid type I migration. This result implies the inevitability of a Galilean satellite formation in addition to providing theoretical predictions for extrasolar satellites. That is, we can predict a substantial number of exomoon systems in the 2

  17. The Tethered Moon

    NASA Technical Reports Server (NTRS)

    Zahnle, Kevin; Lupu, Roxana Elena; Dubrovolskis, A. R.

    2014-01-01

    that the Moon's orbit evolves is limited by the modest radiative cooling rate of Earth's atmosphere, which in effect tethers the Moon to the Earth. Consequently the Moon's orbit evolves orders of magnitude more slowly than in conventional models. Slow orbital evolution promotes capture by orbital resonances that may have been important in the Earth-Moon system

  18. The cryo-penetrator: an approach to exploration of icy bodies in the solar system.

    NASA Astrophysics Data System (ADS)

    Boynton, W. V.; Reinert, R. P.

    The nuclei of comets and the small icy moons of the outer planets are thought to be the most primitive objects in the solar system. Because of their pristine nature, in-situ measurements of composition, temperature, and mechanical properties will be a powerful tool in realization of one of NASA's major objectives: determination of the Solar System's origins and evolution. Cryo penetrators are specifically optimized for penetration and operation in icy bodies at temperatures below 150K. The CRAF studies were directed at investigation of comet nuclei, but the same design should be applicable to the icy moons of the outer planets and, with appropriate delivery systems, to the Martian polar caps. The paper describes the design of a cryopenetrator based on the CRAF configuration and designed for in-situ measurements of a comet nucleus as part of the Comet Nucleus Penetrator Discovery mission. The ROSETTA nucleus rendezvous mission is another potential cryo penetrator application.

  19. Recent Formation of Saturnian Moons: Constraints from Their Cratering Records

    NASA Astrophysics Data System (ADS)

    Dones, Henry C. Luke; Charnoz, Sebastien; Robbins, Stuart J.; Bierhaus, Edward B.

    2015-05-01

    Charnoz et al. (2010) proposed that Saturn's small "ring moons" out to Janus and Epimetheus consist of ring material that viscously spread beyond the Roche limit and coagulated into moonlets. The moonlets evolve outward due to the torques they exert at resonances in the rings. More massive moonlets migrate faster; orbits can cross and bodies can merge, resulting in a steep trend of mass vs. distance from the planet. Canup (2010) theorized that Saturn's rings are primordial and originated when a differentiated, Titan-like moon migrated inward when the planet was still surrounded by a gas disk. The satellite's icy shell could have been tidally stripped, and would have given rise to today's rings and the mid-sized moons out to Tethys. Charnoz et al. (2011) investigated the formation of satellites out to Rhea from a spreading massive ring, and Crida and Charnoz (2012) extended this scenario to other planets. Once the mid-sized moons recede far from the rings, tidal interaction with the planet determines the rate at which the satellites migrate. Charnoz et al. (2011) found that Mimas would have formed about 1 billion years more recently than Rhea. The cratering records of these moons (Kirchoff and Schenk 2010; Robbins et al. 2015) provide a test of this scenario. If the mid-sized moons are primordial, most of their craters were created through hypervelocity impacts by ecliptic comets from the Kuiper Belt/Scattered Disk (Zahnle et al. 2003; Dones et al. 2009). In the Charnoz et al. scenario, the oldest craters on the moons would result from low-speed accretionary impacts. We thank the Cassini Data Analysis program for support.ReferencesCanup, R. M. (2010). Nature 468, 943Charnoz, S.; Salmon, J., Crida, A. (2010). Nature 465, 752Charnoz, S., et al. (2011). Icarus 216, 535Crida, A.; Charnoz, S. (2012). Science 338, 1196Dones, L., et al. (2009). In Saturn from Cassini-Huygens, p. 613Kirchoff, M. R.; Schenk, P. (2010). Icarus 206, 485Robbins, S. J.; Bierhaus, E. B.; Dones, L

  20. Europe reaches the Moon

    NASA Astrophysics Data System (ADS)

    2004-11-01

    A complex package of tests on new technologies was successfully performed during the cruise to the Moon, while the spacecraft was getting ready for the scientific investigations which will come next. These technologies pave the way for future planetary missions. SMART-1 reached its closest point to the lunar surface so far - its first ‘perilune’ - at an altitude of about 5000 kilometres at 18:48 Central European Time (CET) on 15 November. Just hours before that, at 06:24 CET, SMART-1’s solar-electric propulsion system (or ‘ion engine’) was started up and is now being fired for the delicate manoeuvre that will stabilise the spacecraft in lunar orbit. During this crucial phase, the engine will run almost continuously for the next four days, and then for a series of shorter burns, allowing SMART-1 to reach its final operational orbit by making ever-decreasing loops around the Moon. By about mid-January, SMART-1 will be orbiting the Moon at altitudes between 300 kilometres (over the lunar south pole) and 3000 kilometres (over the lunar north pole), beginning its scientific observations. The main purpose of the first part of the SMART-1 mission, concluding with the arrival at the Moon, was to demonstrate new spacecraft technologies. In particular, the solar-electric propulsion system was tested over a long spiralling trip to the Moon of more than 84 million kilometres. This is a distance comparable to an interplanetary cruise. For the first time ever, gravity-assist manoeuvres, which use the gravitational pull of the approaching Moon, were performed by an electrically-propelled spacecraft. The success of this test is important to the prospects for future interplanetary missions using ion engines. SMART-1 has demonstrated new techniques for eventually achieving autonomous spacecraft navigation. The OBAN experiment tested navigation software on ground computers to determine the exact position and velocity of the spacecraft using images of celestial objects taken

  1. The Tethered Moon

    NASA Astrophysics Data System (ADS)

    Zahnle, Kevin; Lupu, R.; Fegley, B.; Marley, M.; Sleep, N.; Dobrovolskis, A.

    2013-10-01

    Cosmic collisions between terrestrial planets resemble somewhat the life cycle of the phoenix: worlds collide, are consumed in flame, and after the debris has cleared, shiny new worlds emerge aglow with possibilities. And glow they do, for they are molten. How brightly they glow, and for how long, is determined by their atmospheres, and by their moons. stop. It is well known that the atmosphere's thermal blanketing effect prevents a magma ocean from cooling rapidly. Several models have considered thick H2O-CO2 atmospheres over cooling magma oceans. These models address how the magma ocean freezes, how long it takes to freeze, and how, when, and what is degassed. stop. The atmosphere over a magmasphere is very hot and so contains the geochemical volatiles that can evaporate from a magma ocean, such as sulfur, alkalis and halogens, in addition to H2O and CO2. We compute 1-D non-gray radiative-convective atmospheric structure models that include all the molecular and atomic opacity sources that would be present in equilibrium over a magma ocean. We use these to compute cooling rates for hot post-giant-impact terrestrial planets. Our model is in excellent asymptotic agreement with two recent independent calculations of the runaway greenhouse limit for H2O-CO2 atmosphere. For cooling of the magma ocean itself, we use parameterizations recommended by Solomatov. stop. Tidal heating of the Earth by the Moon is important, because it is a big term, and because it occurs mostly in mantle materials that are just beginning to freeze, which frustrates freezing. The Moon is entwined with Earth by a negative feedback between thermal blanketing and tidal heating that comes from the temperature-dependent viscosity of the magma ocean. Because of this feedback, the rate that the Moon's orbit evolves is limited by the modest radiative cooling rate of Earth's atmosphere, which in effect tethers the Moon to the Earth. Consequently the Moon's orbit evolves orders of magnitude more slowly

  2. Studying the Surfaces of the Icy Galilean Satellites With JIMO

    NASA Astrophysics Data System (ADS)

    Prockter, L.; Schenk, P.; Pappalardo, R.

    2003-12-01

    The Geology subgroup of the Jupiter Icy Moons Orbiter (JIMO) Science Definition Team (SDT) has been working with colleagues within the planetary science community to determine the key outstanding science goals that could be met by the JIMO mission. Geological studies of the Galilean satellites will benefit from the spacecraft's long orbital periods around each satellite, lasting from one to several months. This mission plan allows us to select the optimal viewing conditions to complete global compositional and morphologic mapping at high resolution, and to target geologic features of key scientific interest at very high resolution. Community input to this planning process suggests two major science objectives, along with corresponding measurements proposed to meet them. Objective 1: Determine the origins of surface features and their implications for geological history and evolution. This encompasses investigations of magmatism (intrusion, extrusion, and diapirism), tectonism (isostatic compensation, and styles of faulting, flexure and folding), impact cratering (morphology and distribution), and gradation (erosion and deposition) processes (impact gardening, sputtering, mass wasting and frosts). Suggested measurements to meet this goal include (1) two dimensional global topographic mapping sufficient to discriminate features at a spatial scale of 10 m, and with better than or equal to 1 m relative vertical accuracy, (2) nested images of selected target areas at a range of resolutions down to the submeter pixel scale, (3) global (albedo) mapping at better than or equal to 10 m/pixel, and (4) multispectral global mapping in at least 3 colors at better than or equal to 100 m/pixel, with some subsets at better than 30 m/pixel. Objective 2. Identify and characterize potential landing sites for future missions. A primary component to the success of future landed missions is full characterization of potential sites in terms of their relative age, geological interest, and

  3. Sounding of Icy Galilean Satellites by Surface Observatories

    NASA Technical Reports Server (NTRS)

    Khurana, K. K.; Banerdt, W. B.; Johnson, T. V.; Russell, C. T.; Kivelson, M. G.; Davis, P. M.; Vidale, J. E.

    2001-01-01

    Several independent geological and geophysical investigations suggest that Europa and Ganymede contain subsurface oceans. Using Jupiter's rotating magnetic field as a primary signal, the magnetometer experiment onboard Galileo has measured secondary induction signals emanating from Europa, Ganymede, and surprisingly Callisto. The strong electromagnetic induction from these moons suggests that large global electrical conductors are located just below their icy crusts. A detailed analysis reveals that global salty oceans with salinity similar to the Earth's ocean and thicknesses in the range of approx. 6-100 kms can explain the induction observed by the Galileo magnetometer. Additional information is contained in the original extended abstract.

  4. The tethered Moon

    NASA Astrophysics Data System (ADS)

    Zahnle, Kevin J.; Lupu, Roxana; Dobrovolskis, Anthony; Sleep, Norman H.

    2015-10-01

    We address the thermal history of the Earth after the Moon-forming impact, taking tidal heating and thermal blanketing by the atmosphere into account. The atmosphere sets an upper bound of ∼100 W/m2 on how quickly the Earth can cool. The liquid magma ocean cools over 2-10 Myr, with longer times corresponding to high angular-momentum events. Tidal heating is focused mostly in mantle materials that are just beginning to freeze. The atmosphere's control over cooling sets up a negative feedback between viscosity-dependent tidal heating and temperature-dependent viscosity of the magma ocean. While the feedback holds, evolution of the Moon's orbit is limited by the modest radiative cooling rate of Earth's atmosphere. Orbital evolution is orders of magnitude slower than in conventional constant Q models, which promotes capture by resonances. The evection resonance is encountered early, when the Earth is molten. Capture by the evection resonance appears certain but unlikely to generate much eccentricity because it is encountered early when the Earth is molten and Q⊕ ≫Q☾. Tidal dissipation in the Earth becomes more efficient (Q⊕ ≪Q☾) later when the Moon is between ∼ 20R⊕ and ∼ 40R⊕. If lunar eccentricity grew great, this was when it did so, perhaps setting the table for some other process to leave its mark on the inclination of the Moon.

  5. The interesting case of the Iota-Cygnids (525 ICY)

    NASA Astrophysics Data System (ADS)

    Andreić, Željko; Šegon, Damir; Vida, Denis; Novoselnik, Filip; Skokić, Ivica

    2014-01-01

    One of the showers recently reported by the Croatian Meteor Network, the Iota-Cygnids (525 ICY), is described. From the 40 available orbits, the mean orbit of the shower and some other parameters were obtained. The Iota-Cygnids were detected from October 16 (Sol.Lon. = 203◦) to November, 19th (Sol.Lon. = 237◦), with a slightly higher activity around October 31 (Sol.Lon. = 218◦). The possible parent body is Asteroid 2001 SS287, with DSH = 0.16, indicating that 525 ICY is probably asteroidal in origin. However, a few more asteroids have DSH < 0.20, so the question of the parent body requires a more detailed study to be solved. In depth analysis of IAU MDC has found two showers that are quite similar to the 525 ICY: 83 OCG and 282 DCY. By gathering additional data outside the IAU MDC, we found out that 282 DCY is a rediscovery of 83 OCG. Also, 525 ICY is identical to 83 OCG, but this fact was not recognized before, probably due to incorrect coordinates for the 83 OCG radiant in the IAU MDC database and the lack of information about the activity period of the showers in the IAU MDC database.

  6. Ferry to the moon

    NASA Astrophysics Data System (ADS)

    Aston, Graeme

    1987-06-01

    Solar-electric propulsion for a fleet of lunar ferry vehicles may allow the creation of a permanent lunar base not long after the turn of the century with greater cost effectiveness than a fleet of chemically powered spacecraft. After delivery by the Space Shuttle to a 300-km earth orbit, the lunar ferry envisioned would travel in spiral trajectory to the moon under the power of 300-kW solar arrays and ten 30-kW Xe-ion engines; each of the solar arrays would be 12 x 61 m long. Each trip between the earth parking orbit and the moon would take about 1 year, so that a fleet of four ferries operating simultaneously could deliver 20 metric tons to a lunar base every 100 days.

  7. Radiation reduction for a spacecraft in low-altitude orbit around Ganymede

    NASA Astrophysics Data System (ADS)

    André, Nicolas

    2010-05-01

    Future missions to the Jupiter System are currently being defined in more detail in collaboration between various space agencies. Radiation will be a major constraint on the available choice of mission profiles. The ESA-led Jupiter Ganymede Orbiter, as part of an international Europa Jupiter System Mission, will focus on the two icy outer Galilean satellites, Ganymede and Callisto, and will avoid the most intense radiation belts of Jupiter, where the doses are maximal. However, it will spend a considerable amount of time within 16 Rj where the dose accumulates most rapidly, since it will be ultimately injected first into an elliptical orbit and then into a polar circular low-altitude orbit around Ganymede. Current radiation models indicate that the spacecraft will accumulate the highest radiation dose during the phase when it will orbit Ganymede for months. However, these models are not appropriate to estimate the dose in orbit around any of the Jovian moons (and, hence, Ganymede) since they do not take into account the local radiation environment of the moons, which differs significantly from the Jovian radiation environment. Jovian moons themselves are indeed shielding a spacecraft from charged particles and, therefore, a significant reduction of the dose should be expected. In this paper we re-analyze available Galileo energetic particle data and provide quantitative estimates for the radiation reduction in a low-altitude orbit around Ganymede.

  8. Compositional Remote Sensing of Icy Planets and Satellites Beyond Jupiter

    NASA Technical Reports Server (NTRS)

    Roush, Ted L.

    2002-01-01

    The peak of the solar energy distribution occurs at visual wavelengths and falls off rapidly in the infrared. This fact, improvements in infrared detector technology, and the low surface temperatures for most icy objects in the outer solar system have resulted in the bulk of telescopic and spacecraft observations being performed at visual and near-infrared wavelengths. Such observations, begun in the early 1970's and continuing to present, have provided compositional information regarding the surfaces of the satellites of Saturn and Uranus, Neptune's moon Triton, Pluto, Pluto's moon Charon, Centaur objects, and Kuiper belt objects. Because the incident sunlight penetrates the surface and interacts with the materials present there, the measured reflected sunlight contains information regarding the surface materials, and the ratio of the reflected to incident sunlight provides a mechanism of identifying the materials that are present.

  9. Infrared astronomy from the Moon

    NASA Technical Reports Server (NTRS)

    Lester, Dan

    1988-01-01

    The Moon offers some remarkable opportunities for performing infrared astronomy. Although the transportation overhead can be expected to be very large compared with that for facilities in Earth orbit, certain aspects of the lunar environment should allow significant simplifications in the design of telescopes with background limited performance, at least in some parts of the thermal infrared spectrum. Why leave the Earth to perform infrared astronomy is addressed as is the reasons for going all the way to the Moon for its environment.

  10. Moon Rise

    NASA Video Gallery

    Aboard the International Space Station in May 2012, Expedition 31 astronaut Don Pettit opened the shutters covering the cupola observation windows in time to watch the moon rise. The time-lapse sce...

  11. Moon Zoo: a Citizen Science Project

    NASA Astrophysics Data System (ADS)

    Bugiolacchi, R.; Crawford, I. A.; Joy, K. H.

    2013-09-01

    Moon Zoo is a citizen science project that utilises internet crowd-sourcing techniques. Moon Zoo users are asked to review images from NASA's Lunar Reconnaissance Orbiter (LRO)[1] spacecraft and perform tasks such as measuring impact crater sizes and identifying morphologically interesting features. The tasks are designed to address issues in lunar science and to aid future exploration of the Moon. In addition to its potential in delivering high quality science outputs, Moon Zoo is also an important educator resource, providing information about the geology of the Moon and geophysical processes in the inner solar system.

  12. Energetic Neutral Atoms from the Moon: Populations, physics, applications, and the future

    NASA Astrophysics Data System (ADS)

    Futaana, Yoshifumi; Barabash, Stas; Wieser, Martin; Bhardwaj, Anil; Wurz, Peter

    the effective protection of the surface from the solar wind proton. Recently, we also developed a new method to obtain the electrostatic surface potential inside the anomaly from ENA observations. Improved ENA sensor will fly to Mercury by a Europe-Japan joint Mercury exploration, BepiColombo, as a part of Mercury Plasma Particle Experiment on board Mercury Magnetospheric Orbiter. The ENA experiment will image precipitating plasma at the surface of Mercury. Field-aligned potential in the precipitating regions is also to be derived. European Jupiter mission, JUpiter ICy moons Explorer (JUICE), will also equip an ENA sensor. ENA environment of the icy moons will be addressed as well.

  13. Low Force Icy Regolith Penetration Technology

    NASA Technical Reports Server (NTRS)

    Metzger, P. T.; Galloway, G. M.; Mantovani, J. G.; Zacny, K.; Zacny, Kris; Craft, Jack

    2011-01-01

    Recent data from the Moon, including LCROSS data, indicate large quantities of water ice and other volatiles frozen into the soil in the permanently shadowed craters near the poles. If verified and exploited, these volatiles will revolutionize spaceflight as an inexpensive source of propellants and other consumables outside Earth's gravity well. This report discusses a preliminary investigation of a method to insert a sensor through such a soiVice mixture to verify the presence, nature, and concentration of the ice. It uses percussion to deliver mechanical energy into the frozen mixture, breaking up the ice and decompacting the soil so that only low reaction forces are required from a rover or spacecraft to push the sensor downward. The tests demonstrate that this method may be ideal for a small platform in lunar gravity. However, there are some cases where the system may not be able to penetrate the icy soil, and there is some risk ofthe sensor becoming stuck so that it cannot be retracted, so further work is needed. A companion project (ISDS for Water Detection on the Lunar Surface) has performed preliminary investigation of a dielectric/thermal sensor for use with this system.

  14. Protecting the Moon

    NASA Astrophysics Data System (ADS)

    Rummel, John

    Historically speaking, the Earth's Moon has been subject to a wide variety of protections and cautions associated with space exploration. Early lunar missions (cf., the Ranger series) were initially subjected to sterilization procedures to protect the Moon from biological contamination, and though these were relaxed in later periods (e.g., Surveyor, Apollo), those measures were never entirely abandoned until the mid-1980s. More recent lunar missions (e.g., Clementine, Lunar Prospector, SMART-1) have only been inadvertently concerned with protection of the Moon—Clementine in the attempt to have it leave the vicinity of the Earth entirely, Lunar Prospector in it end-of-mission crash into the lunar south pole (with a resultant outcry by the Navajo population in the US), and SMART-1 because of the keen attention paid by the astronomical community to its end-of-mission location. While operations on the Moon are not constrained by current COSPAR planetary protection restrictions, an increasing interest in the Moon suggests that additional protections should be imposed in the future. For example, if lunar ices exist as a repository of past impact volatiles, then the contamination of lunar ices with non-organically-clean spacecraft and tools presents an initial concern for the potentially lost science, as well as future resource contamination concerns if such ices are found and can be used to as part of a comprehensive life-support strategy for human outposts. Requirements for the protection of this aspect of the lunar environment, as well as others, has been initiated both within COSPAR and by NASA, which (in NPR 8715.6) now requires orbital debris protection for spacecraft in lunar orbit, and prior approval of any future landing (or crashing) sites on the Moon, requiring those to "be chosen (or precluded) with due regard to the planned usage of those sites in future exploration or scientific study and the interests of other spacefaring nations."

  15. Simulating the Phases of the Moon Shortly After Its Formation

    NASA Astrophysics Data System (ADS)

    Noordeh, Emil; Hall, Patrick; Cuk, Matija

    2014-04-01

    The leading theory for the origin of the Moon is the giant impact hypothesis, in which the Moon was formed out of the debris left over from the collision of a Marssized body with the Earth. Soon after its formation, the orbit of the Moon may have been very different than it is today. We have simulated the phases of the Moon in a model for its formation wherein the Moon develops a highly elliptical orbit with its major axis tangential to the Earth's orbit. This note describes these simulations and their pedagogical value.

  16. Moon (Form-Origin)

    NASA Astrophysics Data System (ADS)

    Tsiapas, Elias

    2014-05-01

    above mentioned process, the thick clouds surrounding Earth-Moon were causing heavy storms and on the outer surface of the rolling Moon, wherever small cavities - or pockets - existed, these would fill up with water. Then, due to the Moon's changing tilt, these pockets were sealed by sediments and as a result, small water tanks are scattered on the successive layers of the Moon, from its centre to its surface. . As this sphere (the Moon) continued to grow, the Earth-Moon system was displaying a double-planet image. The Moon's reverse rolling velocity increased according to the increase of its mass and volume. As the temperature on the surface of the Earth continued to fall, a larger number of bigger sized solid masses were descending from the poles towards the equator, and the Moon could no longer aggregate them. The gathering and interference of solid rocks of great mass acted as the catapult on which the Moon bounced off the Earth and was put into orbit around it..

  17. Moon (Form-Origin)

    NASA Astrophysics Data System (ADS)

    Tsiapas, Elias

    2015-04-01

    above mentioned process, the thick clouds surrounding Earth-Moon were causing heavy storms and on the outer surface of the rolling Moon, wherever small cavities - or pockets - existed, these would fill up with water. Then, due to the Moon's changing tilt, these pockets were sealed by sediments and as a result, small water tanks are scattered on the successive layers of the Moon, from its centre to its surface. . As this sphere (the Moon) continued to grow, the Earth-Moon system was displaying a double-planet image. The Moon's reverse rolling velocity increased according to the increase of its mass and volume. As the temperature on the surface of the Earth continued to fall, a larger number of bigger sized solid masses were descending from the poles towards the equator, and the Moon could no longer aggregate them. The gathering and interference of solid rocks of great mass acted as the catapult on which the Moon bounced off the Earth and was put into orbit around it.

  18. Moon (Form-Origin)

    NASA Astrophysics Data System (ADS)

    Tsiapas, Elias

    2016-04-01

    above mentioned process, the thick clouds surrounding Earth-Moon were causing heavy storms and on the outer surface of the rolling Moon, wherever small cavities - or pockets - existed, these would fill up with water. Then, due to the Moon's changing tilt, these pockets were sealed by sediments and as a result, small water tanks are scattered on the successive layers of the Moon, from its centre to its surface. . As this sphere (the Moon) continued to grow, the Earth-Moon system was displaying a double-planet image. The Moon's reverse rolling velocity increased according to the increase of its mass and volume. As the temperature on the surface of the Earth continued to fall, a larger number of bigger sized solid masses were descending from the poles towards the equator, and the Moon could no longer aggregate them. The gathering and interference of solid rocks of great mass acted as the catapult on which the Moon bounced off the Earth and was put into orbit around it.

  19. Technologies for Icy Bodies Access

    NASA Technical Reports Server (NTRS)

    Carsey, F. D.; Anderson, F. S.; French, L. C.; Green, J. R.; Jones, J. A.; Lane, A. L.; Leger, P. C.; Zimmerman, W. F.

    2001-01-01

    Recent events in planetary exploration have profoundly changed the way both space scientists and the public regard the solar system and our place in it. These events include the Galileo data suggesting subsurface oceans in the Jovian system, ever stronger suggestions of near-surface water on Mars, as well as the complex structure observed for the Mars polar caps. And, of course, interest in icy cometary bodies is as old as humankind. Finally, the Mars north polar cap may conceivably cover and protect an ancient ocean floor, an obvious candidate ancient or extant habitat. In short, our interest in searching for life embraced early on the search for liquid water, and that has led us to an additional appreciation for water ice as both a commonplace partner with liquid water and as an issue to be addressed in the exploration of a host of interesting sites. In general, the spectrum of specialized technology for space exploration has not yet been broadened to include the requirements brought about by exploration of icy sites. We argue that technologies for access, operations, and science in icy solar system sites must be examined and their prioritized development initiated in order to successfully plan missions to these compelling sites over the next two decades. Additional information is contained in the original extended abstract.

  20. ARTEMIS Maneuvers into Lunar Orbit

    NASA Video Gallery

    This animation visualizes the maneuvers required to move the ARTEMIS spacecraft from their kidney-shaped paths on each side of the moon to orbiting the moon. It took one and a half years, over 90 o...

  1. The Icy Cold Heart of Pluto

    NASA Astrophysics Data System (ADS)

    Hamilton, Douglas P.

    2015-11-01

    The locations of large deposits of frozen volatiles on planetary surfaces are largely coincident with areas receiving the minimum annual influx of solar energy; familiar examples include the polar caps of Earth and Mars. For planets tilted by more than 45 degrees, however, the poles actually receive more energy than some other latitudes. Pluto, with its current obliquity of 119 degrees, has minima in its average annual insolation at +/- 27 degrees latitude, with ~1.5% more energy flux going to the equator and ~15% more to the poles. Remarkably, the fraction of annual solar energy incident on different latitudes depends only on the obliquity of the planet and not on any of its orbital parameters.Over millions of years, Pluto's obliquity varies sinusoidally from 102-126 degrees, significantly affecting the latitudinal profile of solar energy deposition. Roughly 1Myr ago, the poles received 15% more energy that today while the equator received 13% less. The energy flux to latitudes between 25-35 degrees is far more stable, remaining low over the presumably billions of years since Pluto acquired its current spin properties. Like the poles at Earth, these mid latitudes on Pluto should be favored for the long-term deposition of volatile ices. This is, indeed, the location of the bright icy heart of Pluto, Sputnik Planum.Reflected light and emitted thermal radiation from Charon increases annual insolation to one side of Pluto by of order 0.02%. Although small, the bulk of the energy is delivered at night to Pluto's cold equatorial regions. Furthermore, Charon's thermal infrared radiation is easily absorbed by icy deposits on Pluto, slowing deposition and facilitating sublimation of volatiles. We argue that the slight but persistent preference for ices to form and survive in the anti-Charon Pluto's heart.

  2. Aperture synthesis imaging from the moon

    NASA Technical Reports Server (NTRS)

    Burns, Jack O.

    1991-01-01

    Four candidate imaging aperture synthesis concepts are described for possible emplacement on the moon beginning in the next decade. These include an optical interferometer with 10 microarcsec resolution, a submillimeter array with 6 milliarcsec resolution, a moon-earth VLBI experiment, and a very low frequency interferometer in lunar orbit.

  3. A testable gravitational capture model for the origin of the Earth's Moon

    NASA Technical Reports Server (NTRS)

    Malcuit, R. J.; Winters, R. R.; Mickelson, M. E.

    1984-01-01

    A gravitational capture model is proposed to explain lunar evolution. The model is divided into five orbital eras. In the first era, it is postulated that the pre-capture Moon formed as a small planetary unit on the inner edge of the Asteroid Zone. Orbital era 2 commenced when the Moon's orbit became Earth-crossing. As the Moon underwent periodic gravitational encounters with Earth in a near Earth orbit (orbital era 3), the lunar body because warmer and thus more easily capture. Era 4 saw the Moon inserted into a geocentric orbit that gradually became more circular. Following orbital circulation, the lunar orbit gradually expanded to its present dimensions (era 5).

  4. Cratering at the Icy Satellites: Experimental Insights

    NASA Astrophysics Data System (ADS)

    Bruck Syal, M.; Schultz, P. H.

    2013-12-01

    Impact cratering processes play a central role in shaping the evolution of icy satellites and in guiding interpretations of various geologic features at these bodies. Accurate reconstruction of icy satellite histories depends in large part upon observed impact crater size-frequency distributions. Determining the extent of impact-induced thermal processing and the retention rates for impact-delivered materials of interest, e.g. organics, at these outer solar system moons is of fundamental importance for assessing their habitability and explaining differing geophysical histories. Hence, knowledge of how the impact process operates in ices or ice-rich materials is critically important. Recent progress in the development of water equations of state, coupled with increasingly efficient 3-D hydrocode calculations, has been used to construct careful numerical studies of melt and vapor generation for water ice targets. Complementary to this approach is experimental work to constrain the effects of differing ice target conditions, including porosity, rock mass fraction, and impact angle. Here we report on results from hypervelocity impact experiments (v~5.5 km/s) into water ice targets, performed at the NASA Ames Vertical Gun Range (AVGR). The setup at the AVGR allows for the use of particulate targets, which is useful for examining the effects of target porosity. Photometry and geophysical modeling both suggest that regolith porosity at the icy satellites is significant. We use a combination of half-space and quarter-space geometries, enabling analysis of the impact-generated vapor plume (half-space geometry), along with shock wave and transient crater growth tracking in a cross-sectional view (quarter-space geometry). Evaluating the impact-generated vapor from porous (φ = 0.5) and non-porous water ice targets provides an extension to previously published vapor production results for dolomite and CO2 ice targets. For the case of a 90 degree impact into porous ice, we

  5. Geochemical Exploration of the Moon.

    ERIC Educational Resources Information Center

    Adler, Isidore

    1984-01-01

    Provides information based on explorations of the Apollo program about the geochemistry of the moon and its importance in developing an understanding of formation/evolution of the solar system. Includes description and some results of orbital remote sensing, lunar x-ray experiments, gamma-ray experiments, alpha-particle experiments, and the Apollo…

  6. EVAPORATION OF ICY PLANETESIMALS DUE TO BOW SHOCKS

    SciTech Connect

    Tanaka, Kyoko K.; Yamamoto, Tetsuo; Tanaka, Hidekazu; Miura, Hitoshi; Nagasawa, Makiko; Nakamoto, Taishi

    2013-02-20

    We present the novel concept of evaporation of planetesimals as a result of bow shocks associated with planetesimals orbiting with supersonic velocities relative to the gas in a protoplanetary disk. We evaluate the evaporation rates of the planetesimals based on a simple model describing planetesimal heating and evaporation by the bow shock. We find that icy planetesimals with radius {approx}>100 km evaporate efficiently even outside the snow line in the stage of planetary oligarchic growth, where strong bow shocks are produced by gravitational perturbations from protoplanets. The obtained results suggest that the formation of gas giant planets is suppressed owing to insufficient accretion of icy planetesimals onto the protoplanet within the {approx}<5 AU disk region.

  7. Are There Oceans Under the Ice of Small Saturnian and Uranian Moons?

    NASA Astrophysics Data System (ADS)

    England, C.

    2003-05-01

    Thermal analysis of the large outer-planetary moons (Titan, Callisto, Ganymede) argue strongly for substantial subsurface oceans if they are made up mostly of rock and ice, and if the rock exhibits radioactivity not too different from that of meteoric and lunar material [1]. For Titania, Rhea, Oberon and Iapetus (the TROI moons) with radii just over 700 km, the existence of oceans is less clear. In these bodies, a subsurface ocean may be likely if the rock has sunk to the center of the moon (i.e., the moon is differentiated) and (1) the radiogenic heating rate is on the higher end of that of lunar samples, (2) the bodies experience tidal heating, or (3) the oceans contain compounds such as ammonia that reduce the freezing point of the aqueous environment. A combination of these occurrences would weigh for a subsurface ocean, perhaps of substantial size. That outer-planetary moons with radii larger than about 200 km (e.g.; Enceladus at 250 km) are spherical argues for separation of light and heavy materials, especially in the larger bodies. Otherwise, the moon exhibits an irregular shape (e.g.; Hyperion at 133 km). Primordial radioactivity and collision events may have aided separation. If present-day radiogenicity is that of lunar samples, natural heating is available to maintain global aqueous environments on all of the TROI moons. The ammonia-water eutectics suggested for Titan [2] provide additional margin. The maintenance of oceans in smaller bodies depends on a balance of internal heat generation and thermal isolation by ice or other insulating material. The more important parameter may be the insulating ice, without which an outer-planetary ocean is not possible. The reduced thermal conductivity for impure ice [3] provides even more likelihood for oceans. Calculations for tidal heating within Europa due to orbital resonances [4] suggest that tidal heating amounts to over 40 times its internal radiogenic heating. A value equal only to natural radiogenic

  8. The tectonics of icy satellites

    NASA Astrophysics Data System (ADS)

    Murchie, S. L.

    The formation of tectonic structures on icy satellites may have resulted from one or more of several geologic processes: global volume change due to internal temperature change, H2O-ice phase changes, or ice-silicate differentiation; mantle convection driven by thermal or compositional heterogeneities; tidal deformation; and impact-related processes including formation of fracture systems, seismic disruption of areas antipodal to impact sites, basin collapse, and global reorientation. Observed tectonic structures and their associated volcanic deposits are classified herein into six basic assemblages: (1) pervasive troughs and scarps occurring at globally coherent orientations; (2) throughgoing troughs and bands of troughs, generally associated with volcanic materials; (3) linear to curvilinear ridges; (4) volcanically modified systems of concentric and radial scarps and furrows; (5) regional volcanic and tectonic centers; and (6) grooved terrain intimately associated with light-colored volcanic deposits. Comparison of these assemblages with predicted manifestations of different geologic processes may lead to some understanding of the relationship of volcanic and tectonic features to the endogenic and exogenic processes that have affected icy satellites.

  9. The Motion of a Satellite of the Moon

    NASA Technical Reports Server (NTRS)

    Lass, Harry

    1960-01-01

    The motion of a satellite of the Moon depends on the potential field due to the Moon as well as the gravitational effects of the Earth and Sun. If one chooses a frame of reference attached to the Moon, it can be shown that the force field resulting from the Sun can be neglected when compared with the perturbing field of the Moon resulting from its oblateness. The effect of the Earth's field on the satellite is of the some order of magnitude as the Moon's perturbing field and must be included in an analysis of the motion of a satellite of the Moon. We will assume that the distance between Earth and Moon remains constant, and we will consider satellite orbits of small eccentricity. It will be shown that a nearly circular polar orbit will digress less than 1 deg from a polar orbit and that the change in eccentricity is less than a factor of e in one year.

  10. Cassini Orbit Determination Performance during Saturn Satellite Tour: August 2005 - January 2006

    NASA Technical Reports Server (NTRS)

    Antreasian, Peter G.; Bordi, J. J.; Criddle, K. E.; Ionasescu, R.; Jacobson, R. A.; Jones, J. B.; MacKenzie, R. A.; Parcher, D. W.; Pelletier, F. J.; Roth, D. C.; Stauch, J. R.

    2007-01-01

    During the period spanning the second Enceladus flyby in July 2005 through the eleventh Titan encounter in January 2006, the Cassini spacecraft was successfully navigated through eight close-targeted satellite encounters. Three of these encounters included the 500 km flybys of the icy satellites Hyperion, Dione and Rhea and five targeted flybys of Saturn's largest moon, Titan. This paper will show how our refinements to Saturn's satellite ephemerides have improved orbit determination predictions. These refinements include the mass estimates of Saturn and its satellites by better than 0.5%. Also, it will be shown how this better orbit determination performance has helped to eliminate several statistical maneuvers that were scheduled to clean-up orbit determination and/or maneuver-execution errors.

  11. The Impact History Of The Moon

    NASA Technical Reports Server (NTRS)

    Cohen, B. A.

    2010-01-01

    The bombardment history of the Earth-Moon system has been debated since the first recognition that the circular features on the Moon may be impact craters. Because the lunar impact record is the only planetary impact record to be calibrated with absolute ages, it underpins our understanding of geologic ages on every other terrestrial planet. One of the more remarkable results to come out of lunar sample analyses is the hypothesis that a large number of impact events occurred on the Moon during a narrow window in time approximately 3.8 to 4.1 billion years ago (the lunar cataclysm ). Subsequent work on the lunar and martian meteorite suites; remote sensing of the Moon, Mars, asteroids, and icy satellites; improved dynamical modeling; and investigation of terrestrial zircons extend the cataclysm hypothesis to the Earth, other terrestrial planets, and possibly the entire solar system. Renewed US and international interest in exploring the Moon offers new potential to constrain the Earth-Moon bombardment history. This paper will review the lunar bombardment record, timing and mechanisms for cataclysmic bombardment, and questions that may be answered in a new age of exploration.

  12. Experimental constraints on the chemical evolution of icy satellites

    SciTech Connect

    Scott, H P; Williams, Q; Ryerson, F J

    2000-01-18

    The inferred internal structure of large icy satellites hinges on the degree to which their rock component has been hydrated: this is due to the low density of hydrated silicates relative to anhydrous silicates. Accordingly, interior models of icy satellites have varied greatly in their estimates of ice thickness due to uncertainties in the density of the underlying rock. Furthermore, as both H{sub 2}O (potentially liquid) and organic materials are likely to be present, icy moons have been postulated to be possible hosts for extraterrestrial life; therefore, the stability of organic material under relevant hydrothermal conditions is an important issue. For example, Ganymede, Titan, and Triton are similar in that high pressure hydrothermal processing of silicates has likely been important in their chemical evolution. With mean densities between 1.8 and 2.1 g/cm{sup 3}, compositional models of these bodies incorporate approximately 50--80% silicate minerals by weight, with ices constituting the remaining mass. Moment of inertia constraints on the internal structure of Ganymede demonstrate that differentiation between rock and ice has occurred: such differentiation has also likely occurred in Titan and Triton. During accretion and differentiation (which could be ongoing), the silicate fraction of their interiors would have interacted with aqueous fluids at moderate to high temperatures and pressures. Indeed, a strong magnetic field appears to be generated by Ganymede implying that interior temperatures are high enough (in excess of 1,000 K) to maintain a liquid iron alloy in this satellite. High temperature/pressure hydrothermal processing at rock-water interfaces would profoundly influence the bulk mineralogy and internal structure of these bodies: the degree of hydration of the rocky fraction of these bodies has been a source of ongoing uncertainty. Surprisingly few phase equilibria data exist for compositions of relevance to hydrothermal interactions on icy

  13. Simulating the Phases of the Moon Shortly after Its Formation

    ERIC Educational Resources Information Center

    Noordeh, Emil; Hall, Patrick; Cuk, Matija

    2014-01-01

    The leading theory for the origin of the Moon is the giant impact hypothesis, in which the Moon was formed out of the debris left over from the collision of a Mars sized body with the Earth. Soon after its formation, the orbit of the Moon may have been very different than it is today. We have simulated the phases of the Moon in a model for its…

  14. Water on the Moon

    NASA Astrophysics Data System (ADS)

    Pendleton, Yvonne

    2015-08-01

    After years of thinking the Moon is dry, we now know there are three ways in which water appears on the Moon today:1) The hypothesized buried deposits of volatiles at the lunar poles were found at Cabeus crater. There are questions about the origin of such volatiles (i.e., in-falling comets & meteorites, migrating surficial OH/H2O, and accumulated release from the interior), but there is no doubt the water is there. This long suspected polar water was the most recent form to be confirmed on the Moon.2) Widespread, thinly- distributed, surficial OH (or H2O) is the most recently formed lunar water, and its discovery was completely unexpected. It occurs across all types of lunar terrain, but is more difficult to detect in the warmer equatorial terrain where thermal emission is strongest. The consensus is that this OH is indeed derived from solar wind H linked to O from the surface silicate rocks. Although pervasive, we don’t know how quickly it forms, nor how mobile it is.3) The amount of water present when the Moon formed is now documented in lunar materials from Apollo samples (preserved in the lunar mantle material found in volcanic glass beads). Sample analyses made during the Apollo days were not sufficiently precise to distinguish between indigenous lunar water and terrestrial contamination. Measurements with modern equipment are not only more precise (both elemental and isotopic), but can be made in a manner to constrain a host of processes (e.g. diffusion, thermal cycling) that have acted on these samples during their residence on the Moon. The mysteries associated with all these ‘water’ forms are being pursued by teams and scientists around the world. The paradigm-shifting work that reported these discoveries in recent years are from: the NASA LCROSS (lunar impact mission) team (2010), M3 team/ on the Indian Chandrayan Mission (2009), and lunar sample chemists (2008). NASA Lunar Reconnaissance Orbiter, GRAIL, ESA Smart-1, Japanese Kaguya, and other

  15. Moon Taxi - A European view

    NASA Astrophysics Data System (ADS)

    Lacaze, J. H.; Grimard, M.; Fazi, C.; Theillier, F.

    1992-08-01

    A review is conducted of transportation concepts for relatively small transfer vehicles for earth-to-lunar orbits, lunar shuttles, and earth-return vehicles. Attention is given to the use of Ariane-5 derivatives to accomplish these tasks specifically in the areas of propellant supply, and vehicle maintenance/logistics. Launcher optimization is considered for these tasks with orbital and payload considerations taken into account. A 'lunar vicinity shuttle' is proposed that can accomplish both lunar landings and returns to lunar orbit. The combination of the vehicles is named the Moon Taxi transportation system, and a preliminary feasibility study indicates the suitability of Ariane-5 products for the mass and Isp targets. Specific technological areas critical for the Moon Taxi concept are: cryogenic propellant control, restartable 10-t-thrust engines, and capsule reentry technologies.

  16. The Brick Moon

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Science fiction writers, like Jules Verne in France and Edward Everett Hale in America, had discovered one of the most vital elements in the formula for space travel-a fertile imagination. The first known proposal for a marned-satellite appears in a story by Hale entitled 'The Brick Moon' published in 1899. The story involved a group of young Bostonians who planned to put an artificial satellite into polar orbit for sailors to use to determine longitude accurately and easily. They planned to send a brick satellite into orbit because the satellite would have to withstand fire very well. The Satellite's 37 inhabitants signaled the Earth in morse code by jumping up and down on the outside of the satellite.

  17. The Moon

    NASA Astrophysics Data System (ADS)

    Warren, P. H.

    2003-12-01

    Oxygen isotopic data suggest that there is a genetic relationship between the constituent matter of the Moon and Earth (Wiechert et al., 2001). Yet lunar materials are obviously different from those of the Earth. The Moon has no hydrosphere, virtually no atmosphere, and compared to the Earth, lunar materials uniformly show strong depletions of even mildly volatile constituents such as potassium, in addition to N2, O2, and H2O (e.g., Wolf and Anders, 1980). Oxygen fugacity is uniformly very low ( BVSP, 1981) and even the earliest lunar magmas seem to have been virtually anhydrous. These features have direct and far-reaching implications for mineralogical and geochemical processes. Basically, they imply that mineralogical diversity and thus variety of geochemical processes are subdued; a factor that to some extent offsets the comparative dearth of available data for lunar geochemistry.The Moon's gross physical characteristics play an important role in the more limited range of selenochemical compared to terrestrial geochemical processes. Although exceptionally large (radius=1,738 km) in relation to its parent planet, the Moon is only 0.012 times as massive as Earth. By terrestrial standards, pressures inside the Moon are feeble: the upper mantle gradient is 0.005 GPa km -1 (versus 0.033 GPa km -1 in Earth) and the central pressure is slightly less than 5 GPa. However, lunar interior pressures are sufficient to profoundly influence igneous processes (e.g., Warren and Wasson, 1979b; Longhi, 1992, 2002), and in this sense the Moon more resembles a planet than an asteroid.Another direct consequence of the Moon's comparatively small size was early, rapid decay of its internal heat engine. But the Moon's thermal disadvantage has resulted in one great advantage for planetology. Lunar surface terrains, and many of the rock samples acquired from them, retain for the most part characteristics acquired during the first few hundred million years of solar system existence. The

  18. A numerical study on collisions of icy bodies using SPH method combined with GRAPE

    NASA Astrophysics Data System (ADS)

    Nakajima, M.; Genda, H.; Ida, S.

    2009-12-01

    We have worked on the collisions of icy bodies using Smoothed Particles Hydrodynamics (SPH) method combined with Gravity PipE (GRAPE) in order to understand the basic behavior of icy bodies during impacts. Collisions of Mars-size rocky bodies have been investigated well, because those collisions are related to the origin of the moon and the formation of the terrestrial planets. On the other hand, collisions of icy bodies have not been studied yet, although these collisions would frequently occur in the solar and extra-solar systems, such as the formation of icy exoplanets. Through our research, we figure out the effect of ice during impact in detail. Our SPH code has two special features. First, GRAvity PipE computer (GRAPE) is used, which calculates the gravitational force of each particle up to 100 times faster than usual computers. Second, SESAME equation of state database is used to build a realistic model, taking into account the effect of phase change. In this research, we focused on differences and similarities between collisions of icy bodies and those of rocky ones, such as a merging criterion. Agnor & Asphaug (2004) have shown that a collision of rocky Mars-size protoplanets leads to an inelastic collision when its relative velocities are smaller than 1.4-1.5v, 1.1-1.2v, 1.1-1.2v when its impact angles are 30, 45, and 60 degrees, respectively. Here, v means escape velocity. The same calculations for icy bodies are performed in our numerical code. They have shown that the merging criterion of icy bodies is the same as that of rocky bodies. In addition to the merging criterion, we also clarify the relationship between impact parameters and the change of solid, liquid/vapor mass ratio due to impacts.

  19. Buzz Aldrin on the Moon

    NASA Technical Reports Server (NTRS)

    1969-01-01

    Astronaut Buzz Aldrin, lunar module pilot, walks on the surface of the Moon near the leg of the Lunar Module (LM) 'Eagle' during the Apollo 11 exravehicular activity (EVA). Astronaut Neil A. Armstrong, commander, took this photograph with a 70mm lunar surface camera. While astronauts Armstrong and Aldrin descended in the Lunar Module (LM) 'Eagle' to explore the Sea of Tranquility region of the Moon, astronaut Michael Collins, command module pilot, remained with the Command and Service Modules (CSM) 'Columbia' in lunar orbit.

  20. The Cold and Icy Heart of Pluto

    NASA Astrophysics Data System (ADS)

    Hamilton, D. P.

    2015-12-01

    The locations of large deposits of frozen volatiles on planetary surfaces are largely coincident with areas receiving the minimum annual influx of solar energy. Thus we have the familiar polar caps of Earth and Mars, but cold equatorial regions for planets with obliquities between 54 and 126 degrees. Furthermore, for tilts between 45-66 degrees and 114-135 degrees the minimum incident energy occurs neither at the pole nor the equator. We find that the annual average insolation is always symmetric about Pluto's equator and is fully independent of the relative locations of the planet's pericenter and equinoxes. Remarkably, this symmetry holds for arbitrary orbital eccentricities and obliquities, and so we provide a short proof in the margin of this abstract. The current obliquity of Pluto is 119 degrees, giving it minima in average annual insolation at +/- 27 degrees latitude, with ~1.5% more flux to the equator and ~15% more to the poles. But the obliquity of Pluto also varies sinusoidally from 102-126 degrees and so, over the past million years, Pluto's annual equatorial and polar fluxes have changed by +15% and -13%, respectively. Interestingly, the energy flux received by latitudes between 25-35 degrees remains nearly constant over the presumably billions of years since Pluto acquired its current orbit and spin properties. Thus these latitudes are continuously cold and should be favored for the long-term deposition of volatile ices; the bright heart of Pluto, Sputnik Planum, extends not coincidentally across these latitudes. Reflected light and emitted thermal radiation from Charon increases annual insolation to one side of Pluto by of order 0.02%. Although small, the bulk of the energy is delivered at night to Pluto's cold equatorial regions. Furthermore, Charon's thermal IR is delivered very efficiently to icy deposits. Over billions of years, ices have preferentially formed and survived in the anti-Charon hemisphere.

  1. The Cold and Icy Heart of Pluto

    NASA Astrophysics Data System (ADS)

    Hamilton, D. P.

    2015-12-01

    The locations of large deposits of frozen volatiles on planetary surfaces are largely coincident with areas receiving the minimum annual influx of solar energy. Thus we have the familiar polar caps of Earth and Mars, but cold equatorial regions for planets with obliquities between 54 and 126 degrees. Furthermore, for tilts between 45-66 degrees and 114-135 degrees the minimum incident energy occurs neither at the pole nor the equator. We find that the annual average insolation is always symmetric about Pluto's equator and is fully independent of the relative locations of the planet's pericenter and equinoxes. Remarkably, this symmetry holds for arbitrary orbital eccentricities and obliquities, and so we provide a short proof in the margin of this abstract. The current obliquity of Pluto is 119 degrees, giving it minima in average annual insolation at /- 27 degrees latitude, with ~1.5% more flux to the equator and ~15% more to the poles. But the obliquity of Pluto also varies sinusoidally from 102-126 degrees and so, over the past million years, Pluto's annual equatorial and polar fluxes have changed by 15% and -13%, respectively. Interestingly, the energy flux received by latitudes between 25-35 degrees remains nearly constant over the presumably billions of years since Pluto acquired its current orbit and spin properties. Thus these latitudes are continuously cold and should be favored for the long-term deposition of volatile ices; the bright heart of Pluto, Sputnik Planum, extends not coincidentally across these latitudes. Reflected light and emitted thermal radiation from Charon increases annual insolation to one side of Pluto by of order 0.02%. Although small, the bulk of the energy is delivered at night to Pluto's cold equatorial regions. Furthermore, Charon's thermal IR is delivered very efficiently to icy deposits. Over billions of years, ices have preferentially formed and survived in the anti-Charon hemisphere.

  2. ICI optical data storage tape

    NASA Technical Reports Server (NTRS)

    Mclean, Robert A.; Duffy, Joseph F.

    1992-01-01

    Optical data storage tape is now a commercial reality. The world's first successful development of a digital optical tape system is complete. This is based on the Creo 1003 optical tape recorder with ICI 1012 write-once optical tape media. Flexible optical media offers many benefits in terms of manufacture; for a given capital investment, continuous, web-coating techniques produce more square meters of media than batch coating. The coated layers consist of a backcoat on the non-active side; on the active side there is a subbing layer, then reflector, dye/polymer, and transparent protective overcoat. All these layers have been tailored for ease of manufacture and specific functional characteristics.

  3. Methone as an icy cosmic model of Earth

    NASA Astrophysics Data System (ADS)

    Kochemasov, G. G.

    2013-09-01

    Developed by the wave comparative planetology conception on priorities of structures (shapes) of celestial bodies over their inner processes [1, 2 & others] is supported by recently imaged small icy saturnian satellites Methone (Fig. 1). With its size about 3 km and thus negligible inner energy it has very spectacular shape of an egg and no traces of impacts (what very surprises impact planetologists!). Any body moving in non-circular keplerian orbit with periodically changing accelerations is a subject of an inertia-gravity forces action (Fig. 3). This action inevitably results in oscillations of body shells. An interference of these oscillations, having in rotating bodies four ortho- and diagonal directions, makes their shapes and structures. The longest fundamental wave 1 forms the tectonic dichotomy - an opposition of convex and concave hemispheres-segments (Fig. 7-9). At Earth they are the Pacific and continental hemispheres. The first overtone wave 2 twice-shorter and long πR brings antipodean tectonic sectors of different levels but joining in an octahedron (Fig.. 4-6, 10-11). At Earth one of examples of such antipodean sectors are the pressed in Arctic and bulging Antarctic. Long ago known, this opposition was very intriguing but never was adequately explained. For the small bodies - asteroids also was noticed an opposition of a sharp (convex) and blunt (concave) ends. Recently obtained an image of a miniature icy saturnian satellite Methone confirms principles of the wave planetology. Having length only about 3 km (radius 1.6 ± 0.6 km) it shows an opposition of convex and flat sides (the fundamental dichotomy) and sharp and blunt ends (a second order dichotomy). In this sense it presents a small cosmic model of Earth. It orbits Saturn between orbits of Mimas and Enceladus, close to the first. One might suspect that Enceladus' gaseous plumes (Fig. 2) could finally accumulate themselves in a small icy body - Methone.

  4. Chemical Processes in the Icy Plumes of Enceladus

    NASA Astrophysics Data System (ADS)

    Boice, D. C.; Goldstein, R.

    2012-12-01

    The icy plumes from Saturn's moon Enceladus are unusual phenomena that have raised several challenging questions about the relationship of this small satellite to its surrounding environment. In addition, they offer a unique window to probe the interior structure and composition of this icy satellite. Measurements of the neutral and ion composition of the plumes by instruments aboard Cassini reveal the presence of water group species, nitrogen-bearing molecules, and other species that are the major volatiles in cometary ices. Our cometary coma model with chemistry (SUISEI) has been adapted to study this problem. SUISEI produces abundances of the gas species; velocities of the bulk gas, light atomic and molecular hydrogen with escape, and electrons; gas and electron temperatures; column densities to facilitate comparison with observations; energy budget quantities; attenuation of the solar irradiance; and other quantities that can be related readily to the in situ measurements. Likely ion-molecule chemistry and other issues are discussed to gain a perspective on our current understanding of Enceladus. Acknowledgements: We acknowledge funding and support from the SwRI Internal Research and Development Program, the NASA Cassini (CAPS) Mission, and the NSF Planetary Astronomy Program.

  5. Very High Resolution Image of Icy Cliffs on Europa

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This image, taken by the camera onboard NASA's Galileo spacecraft, is a very high resolution view of the Conamara Chaos region on Jupiter's moon Europa. It shows an area where icy plates have been broken apart and moved around laterally. The top of this image is dominated by corrugated plateaus ending in icy cliffs over a hundred meters (a few hundred feet) high. Debris piled at the base of the cliffs can be resolved down to blocks the size of a house. A fracture that runs horizontally across and just below the center of the Europa image is about the width of a freeway.

    North is to the top right of the image, and the sun illuminates the surface from the east. The image is centered at approximately 9 degrees north latitude and 274 degrees west longitude. The image covers an area approximately 1.7 kilometers by 4 kilometers (1 mile by 2.5 miles). The resolution is 9 meters (30 feet) per picture element. This image was taken on December 16, 1997 at a range of 900 kilometers (540 miles) by Galileo's solid state imaging system.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

  6. More Surprises from the Moon

    NASA Technical Reports Server (NTRS)

    Petro, Noah

    2011-01-01

    Even with the naked eye, the dark, extensive plains of the lunar maria can be clearly seen on the surface of the Moon. The maria formed after meteorite impacts created large craters that later filled with lava flows. Mare volcanism is the dominant type of volcanic activity on the Moon and the lavas are made up of basaltic rocks. However, non-mare volcanic deposits, though rare, have been observed on the lunar nearside. The deposits are distinguished from the maria because they are compositionally more evolved rich in silica, potassium and thorium. The deposits are limited in surface extent and it was unknown whether similar non-mare volcanism occurred at all on the Moon s farside. Writing in Nature Geoscience, Jolliff et al. report using Lunar Reconnaissance Orbiter images and compositional data to identify the rare occurrence of more compositionally evolved volcanic deposits in an isolated area on the Moon s farside. In the 1960s and 1970s, rock and soil samples were collected by the Apollo and Luna missions, by the USA and USSR respectively. This material represents a geologic treasure trove that continues to provide a wealth of information about the Moon and its evolution, and it was a very small fraction of these samples that gave the first hint that non-mare volcanic activity might have occurred. The samples contained fragments of complex volcanic rocks that were unrelated to the maria basalts. Violent bombardment of the Moon by meteorite impacts has caused significant mixing of the rocks at its surface, so the fragments could have had a source hundreds or thousands of kilometres away. The origin of the fragments was unknown. Several decades later, the Lunar Prospector mission used a gamma-ray spectrometer to map the distribution and abundance of various elements, including thorium, on the Moon s surface. The maps identified a distinct and large area of high thorium concentration, as well as several smaller, but equally peculiar areas of high thorium

  7. Evolution of the Moon

    NASA Video Gallery

    From year to year, the moon never seems to change. Craters and other formations appear to be permanent now, but the moon didn't always look like this. Learn about how the moon evolved from its earl...

  8. Origin and Evolution of the Moon

    NASA Astrophysics Data System (ADS)

    Zhong, Cuixiang

    2014-01-01

    Since the Moon is the only natural satellite of the Earth, the research on the formation of the Moon can not only find out the formation mechanism of the satellites of Solar System planets but also reveal the evolution law of galaxies in the universe. Hence many hypotheses have been proposed for the Moon's formation, including fission,capture,condensation,and impact event hypothesis, but they all have problems. Recently, the author of this abstract discovered the formation mechanism of the Moon, which can be called ``evolution theory'', and described as follows: During some violent volcanic eruptions of the Earth, some rock debris such as pumice through deep rock hole could achieve a velocity no less than the first cosmic velocity (7.9 km/s) to enter an orbit around the Earth, one of the biggest debris is the young Moon. The orbit of the young Moon might be much closer to the Earth than it is today. There were a lot of ejecta from the Earth in the space. Hence, the Moon has merged these ejecta to become larger and larger, and farther and farther away from the Earth.This can be proved as follows: When the Moon moved around the Earth normally, the centrifugal force produced by the Moon's rotation around the Earth and the Earth's gravitation pull on the Moon had the same size. Let M be the mass of the Earth, m 1 be the mass of the Moon, r m be the radius of the Moon, r be the centroid distance between the Earth and the Moon, v be the tangential velocity of the Moon around the Earth, then Gm 1 M/r 2=m 1 v 2/r, therefore $v=\\sqrt{GM/r}$ . Near the orbit of the Moon, there were also many smaller prograde planetesimals moving around the Earth in circular orbits of radius r x (r-r m \\sqrt{GM/r}$ , which implies v x > v, these planetesimals would finally catch and merge with the Moon.Especially,if a planetesimals was large enough, it would impact the Moon forcefully, making the Moon's velocity increase to a larger

  9. MIGRATION OF SMALL MOONS IN SATURN's RINGS

    SciTech Connect

    Bromley, Benjamin C.; Kenyon, Scott J. E-mail: skenyon@cfa.harvard.edu

    2013-02-20

    The motions of small moons through Saturn's rings provide excellent tests of radial migration models. In theory, torque exchange between these moons and ring particles leads to radial drift. We predict that moons with Hill radii r {sub H} {approx} 2-24 km should migrate through the A ring in 1000 yr. In this size range, moons orbiting in an empty gap or in a full ring eventually migrate at the same rate. Smaller moons or moonlets-such as the propellers-are trapped by diffusion of disk material into corotating orbits, creating inertial drag. Larger moons-such as Pan or Atlas-do not migrate because of their own inertia. Fast migration of 2-24 km moons should eliminate intermediate-size bodies from the A ring and may be responsible for the observed large-radius cutoff of r {sub H} {approx} 1-2 km in the size distribution of the A ring's propeller moonlets. Although the presence of Daphnis (r {sub H} Almost-Equal-To 5 km) inside the Keeler gap challenges this scenario, numerical simulations demonstrate that orbital resonances and stirring by distant, larger moons (e.g., Mimas) may be important factors. For Daphnis, stirring by distant moons seems the most promising mechanism to halt fast migration. Alternatively, Daphnis may be a recent addition to the ring that is settling into a low inclination orbit in {approx}10{sup 3} yr prior to a phase of rapid migration. We provide predictions of observational constraints required to discriminate among possible scenarios for Daphnis.

  10. Global Moon Coverage via Hyperbolic Flybys

    NASA Technical Reports Server (NTRS)

    Buffington, Brent; Strange, Nathan; Campagnola, Stefano

    2012-01-01

    The scientific desire for global coverage of moons such as Jupiter's Galilean moons or Saturn's Titan has invariably led to the design of orbiter missions. These orbiter missions require a large amount of propellant needed to insert into orbit around such small bodies, and for a given launch vehicle, the additional propellant mass takes away from mass that could otherwise be used for scientific instrumentation on a multiple flyby-only mission. This paper will present methods--expanding upon techniques developed for the design of the Cassini prime and extended missions--to obtain near global moon coverage through multiple flybys. Furthermore we will show with proper instrument suite selection, a flyby-only mission can provide science return similar (and in some cases greater) to that of an orbiter mission.

  11. More Saturnian Moons

    NASA Astrophysics Data System (ADS)

    2000-10-01

    Saturn takes the lead Following the discovery of at least four additional moons of that planet, Saturn has again taken the lead as the planet with the greatest number of known natural satellites. A corresponding announcement was made today by an international team of astronomers [1] at a meeting of the Division for Planetary Sciences (DPS) of the American Astronomical Society (AAS) in Pasadena (California, USA). The four new faint bodies were spotted during observations in August-September 2000 at several astronomical telescopes around the world. Subsequent orbital calculations have indicated that these objects are almost certainly new satellites of the giant planet. Two Saturnian moons found at La Silla ESO PR Photo 29a/00 ESO PR Photo 29a/00 [Preview - JPEG: 263 x 400 pix - 26k] [Normal - JPEG: 525 x 800 pix - 93k] ESO PR Photo 29b/00 ESO PR Photo 29b/00 [Preview - JPG: 289 x 400 pix - 43k] [Normal - JPG: 578 x 800 pix - 432k] ESO PR Photo 29c/00 ESO PR Photo 29c/00 [Animated GIF: 330 x 400 pix - 208k] Captions : The photos show the discovery images of two new Saturnian moons, as registered on August 7, 2000, with the Wide-Field Imager (WFI) camera at the MPG/ESO 2.2-m telescope at the La Silla Observatory. Photo PR 29a/00 displays the faint image of the newly discovered moon S/2000 S 1 in the lower right corner of the field. A spiral galaxy is seen in the upper left corner of this photo. The other objects are (background) stars in the Milky Way. Photo PR 29b/00 is a combination of three successive WFI exposures of the second moon, S/2000 S 2 . Because of its motion, there are three images (to the left). Photo PR 29c/00 is an animated GIF image of the same three exposures that demonstrates this motion. Technical details are found below. The observations of the first two objects are described on a Circular of the International Astronomical Union (IAU) that was issued today [2]. The images of these new moons were first registered on exposures made on August 7, 2000

  12. Cost-Effective Icy Bodies Exploration using Small Satellite Missions

    NASA Technical Reports Server (NTRS)

    Jonsson, Jonas; Mauro, David; Stupl, Jan; Nayak, Michael; Aziz, Jonathan; Cohen, Aaron; Colaprete, Anthony; Dono-Perez, Andres; Frost, Chad; Klamm, Benjamin; McCafferty, Julian; McKay, Chris; Sears, Derek; Soulage, Michael; Swenson, Jason; Weston, Sasha; Yang Yang, Fan

    2015-01-01

    It has long been known that Saturn's moon Enceladus is expelling water-rich plumes into space, providing passing spacecraft with a window into what is hidden underneath its frozen crust. Recent discoveries indicate that similar events could also occur on other bodies in the solar system, such as Jupiter's moon Europa and the dwarf planet Ceres in the asteroid belt. These plumes provide a possible giant leap forward in the search for organics and assessing habitability beyond Earth, stepping stones toward the long-term goal of finding extraterrestrial life. The United States Congress recently requested mission designs to Europa, to fit within a cost cap of $1B, much less than previous mission designs' estimates. Here, innovative cost-effective small spacecraft designs for the deep-space exploration of these icy worlds, using new and emerging enabling technologies, and how to explore the outer solar system on a budget below the cost horizon of a flagship mission, are investigated. Science requirements, instruments selection, rendezvous trajectories, and spacecraft designs are some topics detailed. The mission concepts revolve around a comparably small-sized and low-cost Plume Chaser spacecraft, instrumented to characterize the vapor constituents encountered on its trajectory. In the event that a plume is not encountered, an ejecta plume can be artificially created by a companion spacecraft, the Plume Maker, on the target body at a location timed with the passage of the Plume Chaser spacecraft. Especially in the case of Ceres, such a mission could be a great complimentary mission to Dawn, as well as a possible future Europa Clipper mission. The comparably small volume of the spacecraft enables a launch to GTO as a secondary payload, providing multiple launch opportunities per year. Plume Maker's design is nearly identical to the Plume Chaser, and fits within the constraints for a secondary payload launch. The cost-effectiveness of small spacecraft missions enables the

  13. Lunar Reconnaissance Orbiter Mission Highlights

    NASA Video Gallery

    Since launch on June 18, 2009 as a precursor mission, the Lunar Reconnaissance Orbiter (LRO) has remained in orbit around the moon, collecting vast amounts of science data in support of NASA's expl...

  14. Numerical Study of Orbits around Europa

    NASA Astrophysics Data System (ADS)

    Mourao, Decio; Carvalho, Jean Paulo; Vilhena de Moraes, Rodolpho; Cardoso dos Santos, Josué; Campos de Carvalho Costa, Luis Fernando

    NASA's Galileo spacecraft probe recently discovered what appears to be a body of liquid water locked inside the icy shell of Jupiter’s moon Europa. The improved likelihood of life on Europa motivated new mission proposals. In this work we used numerical simulations to compare several possible orbits of satellites near the surface of Europa. We spread a set of particles around the satellite with different initially conditions, from 50 to 500km altitude and inclinations higher than 35 degrees, and we monitored the evolution of the test particles during the numerical integrations. We consider the effect of the oblateness of Europa by considering the C22,J2 and J4 parameters and Jupiter gravitational perturbation. These perturbations were first accounted for separately in order to better understand the importance of each effect, and then considered jointly. All particles collide with the Europa surface in a few days. The oblateness of Jupiter alone causes particles with high inclination to collide with the surface of Europa, while the oblateness of Europa affects low orbits decreasing the lifetime of most of the particles. We identified a stable region of orbits with initial altitudes around 300 km of altitude and 90 degrees of inclination. Particles in this region survived more than 200 days. In most of the simulations pericenter initial values near 90 or 270 degrees favor a higher lifetime for the particles, even when considering Europa oblateness.

  15. Emergence of Habitable Environments in Icy World Interiors

    NASA Astrophysics Data System (ADS)

    Neveu, Marc

    2016-07-01

    Finding habitable worlds is a key driver of solar system exploration. Many solar system missions seek environments providing liquid water, energy, and nutrients, the three ingredients necessary to sustain life [1]. Such environments include hydrothermal systems, spatially confined systems where hot aqueous fluid circulates through rock by convection. Hydrothermal activity may be widespread in the solar system. Most solar system worlds larger than 200 km in radius are icy moons and dwarf planets, likely composed of an icy, cometary mantle surrounding a rocky, chondritic core [2]. By improving an icy world evolution code [3] to include the effects of core fracturing and hydrothermal circulation, I show that several icy moons and dwarf planets likely have undergone extensive water-rock interaction [4,5]. This supports observations of aqueous products on their surfaces [6,7]. I simulated the alteration of chondritic rock [8] by pure water or fluid of cometary composition [9] to show that aqueous alteration feeds back on geophysical evolution: it modifies the fluid antifreeze content, affecting its persistence over geological timescales; and the distribution of radionuclides, whose decay is a chief heat source on dwarf planets [10]. Hydrothermal circulation also efficiently transports heat from the core into the ocean, thereby increasing ocean persistence [4]. Thus, these coupled geophysical-geochemical models provide a comprehensive picture of icy world evolution and the emergence of liquid environments in chemical disequilibrium with underlying rock in their interiors. Habitable settings also require a suitable supply of bioessential elements; but what constitutes "suitable"? I sought to quantify the bulk elemental composition of hydrothermal microbial communities, collected in hot spring sediments and mats at Yellowstone National Park, USA. To do so, one must minimize the contribution of non-biological material to the samples analyzed. This was achieved using a

  16. Plume Collection Strategies for Icy World Sample Return

    NASA Technical Reports Server (NTRS)

    Neveu, M.; Glavin, D. P.; Tsou, P.; Anbar, A. D.; Williams, P.

    2015-01-01

    Three icy worlds in the solar system display evidence of pluming activity. Water vapor and ice particles emanate from cracks near the south pole of Saturn's moon Enceladus. The plume gas contains simple hydrocarbons that could be fragments of larger, more complex organics. More recently, observations using the Hubble and Herschel space telescopes have hinted at transient water vapor plumes at Jupiter's moon Europa and the dwarf planet Ceres. Plume materials may be ejected directly from possible sub-surface oceans, at least on Enceladus. In such oceans, liquid water, organics, and energy may co-exist, making these environments habitable. The venting of habitable ocean material into space provides a unique opportunity to capture this material during a relatively simple flyby mission and return it to Earth. Plume collection strategies should enable investigations of evidence for life in the returned samples via laboratory analyses of the structure, distribution, isotopic composition, and chirality of the chemical components (including biomolecules) of plume materials. Here, we discuss approaches for the collection of dust and volatiles during flybys through Enceladus' plume, based on Cassini results and lessons learned from the Stardust comet sample return mission. We also highlight areas where sample collector and containment technology development and testing may be needed for future plume sample return missions.

  17. Modeling Radar Scatter from Icy and Young Rough Lunar Craters

    NASA Technical Reports Server (NTRS)

    Thompson, Thomas (Tommy); Ustinov, Eugene; Spudis, Paul; Fessler, Brian

    2012-01-01

    For lunar orbital synthetic aperture radars, such as the Chandrayaan Mini-RF operating at S- band (13-cm) wavelength and the Lunar Reconnaissance Orbiter Mini-RF operating at S- band and X-band (3-cm) wavelengths, it is important to understand the radar backscattering characteristics of the icy and young, rough craters. Assuming a mixing model consisting of diffuse and quasi-specular scattering components, we have modeled the opposite-sense circular (OC) and same-sense circular (SC) backscattering characteristics. The specular component, consisting of only OC echoes, represents the echoes from the surface and subsurface layers that are oriented perpendicular to the radar's line-of-sight. The diffuse component, consisting of both SC and OC echoes, represents the echoes associated with either rocks or ice. Also, diffuse echoes have backscatter that is proportional to the cosine of the incidence angle. We modeled how these two (specular and diffuse) radar scattering components could be modulated by factors such as surface roughness associated with young craters. We also modeled how ice radar scattering components could be modulated by a thin regolith covering, and/or by the situation where ice occupies small patches within a larger radar pixel. We tested this modeling by examining 4 nonpolar craters and 12 polar craters using LRO Mini-RF data. Results indicate that icy and young rough craters can be distinguished based upon their SC enhancements (Alpha) and OC enhancements (Gamma). In addition, we also examined the craters that have unusual circular polarization ratios (CPRs) that likely result from a double bounce mode of scattering. Blocky fresh craters, icy craters, and craters exhibiting double bounce scattering can be separated based on the values of Alpha, Gamma, the ratio of Alpha/Gamma and the weighted sum of Alpha and Gamma.

  18. MAJIS, the Moons And Jupiter Imaging Spectrometer, designed for the future ESA/JUICE mission

    NASA Astrophysics Data System (ADS)

    Piccioni, Giuseppe; Langevin, Yves; Filacchione, Gianrico; Poulet, Francois; Tosi, Federico; Eng, Pascal; Dumesnil, Cydalise; Zambelli, Massimo; Saggin, Bortolino; Fonti, Sergio; Grassi, Davide; Altieri, Francesca

    2014-05-01

    The Moons And Jupiter Imaging Spectrometer (MAJIS) is the VIS-IR spectral mapper selected for JUICE (Jupiter Icy Moon Explorer), the first Large-class mission in the ESA Cosmic Vision Programme. Scheduled for a launch in 2022, JUICE will perform a comprehensive exploration of the Jovian system thanks to several flybys of Callisto, Ganymede and Europa, before finally entering orbit around Ganymede. During these phases, MAJIS will acquire hyperspectral data necessary to unveil and map the surface composition of different geologic units of the satellites. Transfers between successive satellites' flybys shall be devoted to remote observations of Jupiter's atmosphere and auroras. MAJIS' instrument design relies on a 75 mm pupil, f/3.2 aperture TMA telescope matching two Czerny-Turner imaging spectrometers. A dichroic element is used to split the beam between the two spectral channels. The VIS-NIR spectral channel covers the 0.4-1.9 μm range with a sampling of 2.3 nm/band. The IR channel works in the 1.5-5.7 μm range with a 6.6 nm/band sampling. The entire optical structure is passively cooled at cryogenic temperature

  19. The cryo-penetrator: An approach to exploration of icy bodies in the solar system

    NASA Astrophysics Data System (ADS)

    Boynton, W. V.; Reinert, R. P.

    1995-01-01

    The nuclei of comets and the small icy moons of the outer planets are thought to be the most primitive objects in the solar system. Because of their pristine nature, in-situ measurements of composition, temperature, and mechanical properties will be a powerful tool in realization of one of NASA's major objectives: determination of the Solar System's origins and evolution. Cryo penetrators are a new class of penetrator vehicle investigated intensively since 1985 for NASA's Comet Rendezvous/Asteroid Flyby (CRAF) mission. They are specifically optimized for penetration and operation in icy bodies at temperatures below 150 degrees K. The CRAF studies were directed at investigation of comet nuclei, but the same design should be applicable to the icy moons of the outer planets and, with appropriate delivery systems, (similar to those envisioned for NASA's MESUR mission) to the Martian polar caps. This paper describes the design of a cryopenetrator based on the CRAF Configuration and designed for in-situ measurements of a comet nucleus as part of the Comet Nucleus Penetrator (CNP) Discovery mission. The ROSETTA nucleus rendezvous mission recently selected by ESA is another potential cryo penetrator application.

  20. Russian Scientific Project: "The Moon - 2012+"

    NASA Astrophysics Data System (ADS)

    Gusev, A.; Petrova, N.

    2006-08-01

    The realization of the modern long-time programs of comprehensive investigation of the Moon in the framework: "SMART-1" (ESA, 2003+), "SELENE" (JAXA, 2007), "Chandrayaan" (India, 2007), "CHANG'E-I" (CNSA, 2007), "LRO" (NASA, 2008), and "Luna Glob" (Russia, 2012) are aimed at obtaining of broad information about lunar gravity field, precision position in the inertial coordinate system, geometrical and dynamical figure and lunar interior: qualitative parameter Q, Love number k[2], core's radius R[c], core's density etc. Russian scientific project "The Moon - 2012+" is directed on the decision of fundamental problems of celestial mechanics, selenodesy and geophysics of the Moon connected to carrying out of complex theoretical researches and computer modelling: 1. Spin-orbital long-time evolution and physical librations the multilayered Moon: ?) construction of the analytical theory of rotation of the two/ three-layer Moon and reception on its basis of physical libration tables for their application at processing precision supervisions; construction of a lunar annual book. b) The analysis of spin-orbital evolution of the early Moon, an estimation of internal energy dissipation, modelling of the long-term mechanism of maintenance free librations the Moon. 2. Geodynamics of a lunar core: the analysis of differentiation of a lunar core, detailed elaboration of plume-tectonics of a mantle and a core of the early Moon, evolution of a boundary layer a core - mantle, reconstruction of gravitational and viscous - mechanical interaction of a lunar core and a mantle, resonant dissipation of internal energy, calculation free and forced nutations a lunar core, free fluctuations of system a core - mantle. 3. Selenodesy of lunar far - side: the decision of a return problem lunar gravimetry, construction of geodynamic model of a lunar crust, a mantle and a core, border Moho, reconstruction initial mascons on the Moon, creation precision topographical and gravitational models of the

  1. More Saturnian Moons

    NASA Astrophysics Data System (ADS)

    2000-10-01

    Saturn takes the lead Following the discovery of at least four additional moons of that planet, Saturn has again taken the lead as the planet with the greatest number of known natural satellites. A corresponding announcement was made today by an international team of astronomers [1] at a meeting of the Division for Planetary Sciences (DPS) of the American Astronomical Society (AAS) in Pasadena (California, USA). The four new faint bodies were spotted during observations in August-September 2000 at several astronomical telescopes around the world. Subsequent orbital calculations have indicated that these objects are almost certainly new satellites of the giant planet. Two Saturnian moons found at La Silla ESO PR Photo 29a/00 ESO PR Photo 29a/00 [Preview - JPEG: 263 x 400 pix - 26k] [Normal - JPEG: 525 x 800 pix - 93k] ESO PR Photo 29b/00 ESO PR Photo 29b/00 [Preview - JPG: 289 x 400 pix - 43k] [Normal - JPG: 578 x 800 pix - 432k] ESO PR Photo 29c/00 ESO PR Photo 29c/00 [Animated GIF: 330 x 400 pix - 208k] Captions : The photos show the discovery images of two new Saturnian moons, as registered on August 7, 2000, with the Wide-Field Imager (WFI) camera at the MPG/ESO 2.2-m telescope at the La Silla Observatory. Photo PR 29a/00 displays the faint image of the newly discovered moon S/2000 S 1 in the lower right corner of the field. A spiral galaxy is seen in the upper left corner of this photo. The other objects are (background) stars in the Milky Way. Photo PR 29b/00 is a combination of three successive WFI exposures of the second moon, S/2000 S 2 . Because of its motion, there are three images (to the left). Photo PR 29c/00 is an animated GIF image of the same three exposures that demonstrates this motion. Technical details are found below. The observations of the first two objects are described on a Circular of the International Astronomical Union (IAU) that was issued today [2]. The images of these new moons were first registered on exposures made on August 7, 2000

  2. Cryovolcanism on the icy satellites

    NASA Astrophysics Data System (ADS)

    Kargel, J. S.

    1994-01-01

    Evidence of past cryovolcanism is widespread and extremely varied on the icy satellites. Some cryovolcanic landscapes, notably on Triton, are similar to many silicate volcanic terrains, including what appear to be volcanic rifts, calderas and solidified lava lakes, flow fields, breached cinder cones or stratovolcanoes, viscous lava domes, and sinuous rilles. Most other satellites have terrains that are different in the important respect that no obvious volcanoes are present. The preserved record of cryovolcanism generally is believed to have formed by eruptions of aqueous solutions and slurries. Even Triton's volcanic crust, which is covered by nitrogen-rich frost, is probably dominated by water ice. Nonpolar and weakly polar molecular liquids (mainly N2, CH4, CO, CO2, and Ar), may originate by decomposition of gas-clathrate hydrates and may have been erupted on some icy satellites, but without water these substances do not form rigid solids that are stable against sublimation or melting over geologic time. Triton's plumes, active at the time of Voyager 2's flyby, may consist of multicomponent nonpolar gas mixtures. The plumes may be volcanogenic fumaroles or geyserlike emissions powered by deep internal heating, and, thus, the plumes may be indicating an interior that is still cryomagmatically active; or Triton's plumes may be powered by solar heating of translucent ices very near the surface. The Uranian and Neptunian satellites Miranda, Ariel, and Triton have flow deposits that are hundreds to thousands of meters thick (implying highly viscous lavas); by contrast, the Jovian and Saturnian satellites generally have plains-forming deposits composed of relatively thin flows whose thicknesses have not been resolved in Voyager images (thus implying relatively low-viscosity lavas). One possible explanation for this inferred rheological distinction involves a difference in volatile composition of the Uranian and Neptunian satellites on one hand and of the Jovian and

  3. Cryovolcanism on the icy satellites

    USGS Publications Warehouse

    Kargel, J.S.

    1994-01-01

    Evidence of past cryovolcanism is widespread and extremely varied on the icy satellites. Some cryovolcanic landscapes, notably on Triton, are similar to many silicate volcanic terrains, including what appear to be volcanic rifts, calderas and solidified lava lakes, flow fields, breached cinder cones or stratovolcanoes, viscous lava domes, and sinuous rilles. Most other satellites have terrains that are different in the important respect that no obvious volcanoes are present. The preserved record of cryovolcanism generally is believed to have formed by eruptions of aqueous solutions and slurries. Even Triton's volcanic crust, which is covered by nitrogen-rich frost, is probably dominated by water ice. Nonpolar and weakly polar molecular liquids (mainly N2, CH4, CO, CO2, and Ar), may originate by decomposition of gas-clathrate hydrates and may have been erupted on some icy satellites, but without water these substances do not form rigid solids that are stable against sublimation or melting over geologic time. Triton's plumes, active at the time of Voyager 2's flyby, may consist of multicomponent nonpolar gas mixtures. The plumes may be volcanogenic fumaroles or geyserlike emissions powered by deep internal heating, and, thus, the plumes may be indicating an interior that is still cryomagmatically active; or Triton's plumes may be powered by solar heating of translucent ices very near the surface. The Uranian and Neptunian satellites Miranda, Ariel, and Triton have flow deposits that are hundreds to thousands of meters thick (implying highly viscous lavas); by contrast, the Jovian and Saturnian satellites generally have plains-forming deposits composed of relatively thin flows whose thicknesses have not been resolved in Voyager images (thus implying relatively low-viscosity lavas). One possible explanation for this inferred rheological distinction involves a difference in volatile composition of the Uranian and Neptunian satellites on one hand and of the Jovian and

  4. The Second Ring-Moon System of Uranus: Discovery and Dynamics

    NASA Technical Reports Server (NTRS)

    Showalter, M. R.; Lissauer, J. J.

    2005-01-01

    Deep exposures of Uranus taken with the Hubble Space Telescope reveal two small moons and two faint rings. All orbit outside of Uranus's previously known (main) ring system, but interior to the large, classical moons. The outer new moon, U XXVI Mab, orbits at roughly twice the radius of the main rings and shares its orbit with a dust ring. The second moon, U XXVII Cupid, orbits just interior to the satellite Belinda. A second ring falls between the orbits of Portia and Rosalind, in a region with no known source bodies. Collectively, these constitute a densely-packed, rapidly varying and possibly unstable dynamica1 system.

  5. The second ring-moon system of Uranus: discovery and dynamics.

    PubMed

    Showalter, Mark R; Lissauer, Jack J

    2006-02-17

    Deep exposures of Uranus taken with the Hubble Space Telescope reveal two small moons and two faint rings. All of them orbit outside of Uranus's previously known (main) ring system but are interior to the large, classical moons. The outer new moon, U XXVI Mab, orbits at roughly twice the radius of the main rings and shares its orbit with a dust ring. The second moon, U XXVII Cupid, orbits just interior to the satellite Belinda. A second ring falls between the orbits of Portia and Rosalind, in a region with no known source bodies. Collectively, these constitute a densely packed, rapidly varying, and possibly unstable dynamical system. PMID:16373533

  6. MOA-2011-BLG-262Lb: A Sub-Earth-Mass Moon Orbiting a Gas Giant Primary or a High Velocity Planetary System in the Galactic Bulge

    NASA Astrophysics Data System (ADS)

    Bennett, D. P.; Batista, V.; Bond, I. A.; Bennett, C. S.; Suzuki, D.; Beaulieu, J.-P.; Udalski, A.; Donatowicz, J.; Bozza, V.; Abe, F.; Botzler, C. S.; Freeman, M.; Fukunaga, D.; Fukui, A.; Itow, Y.; Koshimoto, N.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Namba, S.; Ohnishi, K.; Rattenbury, N. J.; Saito, To.; Sullivan, D. J.; Sumi, T.; Sweatman, W. L.; Tristram, P. J.; Tsurumi, N.; Wada, K.; Yock, P. C. M.; MOA Collaboration; Albrow, M. D.; Bachelet, E.; Brillant, S.; Caldwell, J. A. R.; Cassan, A.; Cole, A. A.; Corrales, E.; Coutures, C.; Dieters, S.; Dominis Prester, D.; Fouqué, P.; Greenhill, J.; Horne, K.; Koo, J.-R.; Kubas, D.; Marquette, J.-B.; Martin, R.; Menzies, J. W.; Sahu, K. C.; Wambsganss, J.; Williams, A.; Zub, M.; PLANET Collaboration; Choi, J. Y.; DePoy, D. L.; Dong, Subo; Gaudi, B. S.; Gould, A.; Han, C.; Henderson, C. B.; McGregor, D.; Lee, C.-U.; Pogge, R. W.; Shin, I.-G.; Yee, J. C.; μFUN Collaboration; Szymański, M. K.; Skowron, J.; Poleski, R.; Kozłowski, S.; Wyrzykowski, Ł.; Kubiak, M.; Pietrukowicz, P.; Pietrzyński, G.; Soszyński, I.; Ulaczyk, K.; OGLE Collaboration; Tsapras, Y.; Street, R. A.; Dominik, M.; Bramich, D. M.; Browne, P.; Hundertmark, M.; Kains, N.; Snodgrass, C.; Steele, I. A.; RoboNet Collaboration; Dekany, I.; Gonzalez, O. A.; Heyrovský, D.; Kandori, R.; Kerins, E.; Lucas, P. W.; Minniti, D.; Nagayama, T.; Rejkuba, M.; Robin, A. C.; Saito, R.

    2014-04-01

    We present the first microlensing candidate for a free-floating exoplanet-exomoon system, MOA-2011-BLG-262, with a primary lens mass of M host ~ 4 Jupiter masses hosting a sub-Earth mass moon. The argument for an exomoon hinges on the system being relatively close to the Sun. The data constrain the product ML πrel where ML is the lens system mass and πrel is the lens-source relative parallax. If the lens system is nearby (large πrel), then ML is small (a few Jupiter masses) and the companion is a sub-Earth-mass exomoon. The best-fit solution has a large lens-source relative proper motion, μrel = 19.6 ± 1.6 mas yr-1, which would rule out a distant lens system unless the source star has an unusually high proper motion. However, data from the OGLE collaboration nearly rule out a high source proper motion, so the exoplanet+exomoon model is the favored interpretation for the best fit model. However, there is an alternate solution that has a lower proper motion and fits the data almost as well. This solution is compatible with a distant (so stellar) host. A Bayesian analysis does not favor the exoplanet+exomoon interpretation, so Occam's razor favors a lens system in the bulge with host and companion masses of M_host = 0.12^{+0.19}_{ -0.06}\\,M_\\odot and m_comp = 18^{+28}_{ -10}\\,{M_\\oplus }, at a projected separation of a_\\perp = 0.84^{+0.25}_{ -0.14} AU. The existence of this degeneracy is an unlucky accident, so current microlensing experiments are in principle sensitive to exomoons. In some circumstances, it will be possible to definitively establish the mass of such lens systems through the microlensing parallax effect. Future experiments will be sensitive to less extreme exomoons.

  7. The optimal launching of a space vehicle from the surface of the moon to a fixed point on the circular orbit of its artificial satellite

    NASA Astrophysics Data System (ADS)

    Grigor'ev, K. G.; Zapletina, E. V.; Zapletin, M. P.

    1992-06-01

    The paper presents an analysis and results of a numerical solution, based on the maximum principle, of three types of problems concerning the optimal launching of a space vehicle with a high-thrust rocket engine from the lunar surface to a fixed point on the circular orbit of a lunar artificial satellite. Attention is given to the problems of the fastest possible launching time, launching with minimal mass expenditure, and minimal trade-off functional (a compromise between expenditures for launch time and mass). The shooting method is used to obtain exact numerical solutions for the appropriate maximum principle boundary problems.

  8. Organics Analyzer for Sampling Icy Surfaces: A liquid chromatograph-mass spectrometer for future in situ small body missions

    NASA Astrophysics Data System (ADS)

    Getty, Stephanie A.; Dworkin, Jason P.; Glavin, Daniel P.; Martin, Mildred; Zheng, Yun; Balvin, Manuel; Southard, Adrian E.; Feng, Steven; Ferrance, Jerome; Kotecki, Carl; Malespin, Charles; Mahaffy, Paul R.

    Liquid chromatography mass spectrometry (LC-MS) is an important laboratory technique for the detection and analysis of organic molecules with high sensitivity and selectivity. This approach has been especially fruitful in the analysis of nucleobases, amino acids, and measuring amino acid enantiomeric ratios in extraterrestrial materials. We are developing OASIS, Organics Analyzer for Sampling Icy Surfaces, for in situ analysis on future landed missions to astrochemically important icy bodies, such as asteroids, comets, and icy moons. The OASIS design employs a microfabricated, on-chip analytical column to chromatographically separate liquid analytes using known LC stationary phase chemistries. The elution products are then interfaced through spray ionization and analyzed by a time-of-flight mass spectrometer (TOF-MS). A particular advantage of our design is its suitability for microgravity environments, such as for a primitive small body.

  9. The rheology of icy satellites

    NASA Technical Reports Server (NTRS)

    Sammis, C. G.

    1984-01-01

    High-temperature creep in orthoenstatite under conditions of controlled oxygen fugacity was studied. It was found that creep was conttrolled by the extremely thin layer of SiO2 which wetted the grain boundaries. Slight reduction of the (Mg, Fe)SiO3 enstatite during hot pressing produced microscopic particles of Fe and the thin film of intergranular SiO2. This result highlights another complication in determining the flow properties of iron bearing silicates which constitute the bulk of terrestrial planets and moons. The Phenomenon may be important in the ductile formation of any extraterrestrial body which is formed in a reducing environment. The rheology of dirty ice was studied. This involves micromechanical modeling of hardening phenomena due to contamination by a cosmic distribution of silicate particles. The larger particles are modeled by suspension theory. In order to handle the distribution of particles sizes, the hardening is readed as a critical phenomenon, and real space renormalization group techniques are used. Smaller particles interact directly with the dislocations. The particulate hardening effect was studied in metals. The magnitude of such hardening in ice and the defect chemistry of ice are studied to assess the effects of chemical contamination by methane, ammonia, or other likely contaminants.

  10. MOA-2011-BLG-262Lb: A sub-Earth-mass moon orbiting a gas giant primary or a high velocity planetary system in the galactic Bulge

    SciTech Connect

    Bennett, D. P.; Batista, V.; Bond, I. A.; Ling, C. H.; Bennett, C. S.; Suzuki, D.; Koshimoto, N.; Beaulieu, J.-P.; Udalski, A.; Donatowicz, J.; Bozza, V.; Abe, F.; Fukunaga, D.; Itow, Y.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Botzler, C. S.; Freeman, M.; Fukui, A.; Collaboration: MOA Collaboration; PLANET Collaboration; μFUN Collaboration; OGLE Collaboration; RoboNet Collaboration; and others

    2014-04-20

    We present the first microlensing candidate for a free-floating exoplanet-exomoon system, MOA-2011-BLG-262, with a primary lens mass of M {sub host} ∼ 4 Jupiter masses hosting a sub-Earth mass moon. The argument for an exomoon hinges on the system being relatively close to the Sun. The data constrain the product M{sub L} π{sub rel} where M{sub L} is the lens system mass and π{sub rel} is the lens-source relative parallax. If the lens system is nearby (large π{sub rel}), then M{sub L} is small (a few Jupiter masses) and the companion is a sub-Earth-mass exomoon. The best-fit solution has a large lens-source relative proper motion, μ{sub rel} = 19.6 ± 1.6 mas yr{sup –1}, which would rule out a distant lens system unless the source star has an unusually high proper motion. However, data from the OGLE collaboration nearly rule out a high source proper motion, so the exoplanet+exomoon model is the favored interpretation for the best fit model. However, there is an alternate solution that has a lower proper motion and fits the data almost as well. This solution is compatible with a distant (so stellar) host. A Bayesian analysis does not favor the exoplanet+exomoon interpretation, so Occam's razor favors a lens system in the bulge with host and companion masses of M{sub host}=0.12{sub −0.06}{sup +0.19} M{sub ⊙} and m{sub comp}=18{sub −10}{sup +28} M{sub ⊕}, at a projected separation of a{sub ⊥}=0.84{sub −0.14}{sup +0.25} AU. The existence of this degeneracy is an unlucky accident, so current microlensing experiments are in principle sensitive to exomoons. In some circumstances, it will be possible to definitively establish the mass of such lens systems through the microlensing parallax effect. Future experiments will be sensitive to less extreme exomoons.

  11. Icy Satellites of Saturn: Impact Cratering and Age Determination

    NASA Technical Reports Server (NTRS)

    Dones, L.; Chapman, C. R.; McKinnon, William B.; Melosh, H. J.; Kirchoff, M. R.; Neukum, G.; Zahnle, K. J.

    2009-01-01

    Saturn is the first giant planet to be visited by an orbiting spacecraft that can transmit large amounts of data to Earth. Crater counts on satellites from Phoebe inward to the regular satellites and ring moons are providing unprecedented insights into the origin and time histories of the impacting populations. Many Voyager-era scientists concluded that the satellites had been struck by at least two populations of impactors. In this view, the Population I impactors, which were generally judged to be comets orbiting the Sun, formed most of the larger and older craters, while Population II impactors, interpreted as Saturn-orbiting ejecta from impacts on satellites, produced most of the smaller and younger craters. Voyager data also implied that all of the ring moons, and probably some of the midsized classical moons, had been catastrophically disrupted and reaccreted since they formed. We examine models of the primary impactor populations in the Saturn system. At the present time, ecliptic comets, which likely originate in the Kuiper belt/scattered disk, are predicted to dominate impacts on the regular satellites and ring moons, but the models require extrapolations in size (from the observed Kuiper belt objects to the much smaller bodies that produce the craters) or in distance (from the known active Jupiter family comets to 9.5 AU). Phoebe, Iapetus, and perhaps even moons closer to Saturn have been struck by irregular satellites as well. We describe the Nice model, which provides a plausible mechanism by which the entire Solar System might have experienced an era of heavy bombardment long after the planets formed. We then discuss the three cratering chronologies, including one based upon the Nice model, that have been used to infer surface ages from crater densities on the saturnian satellites. After reviewing scaling relations between the properties of impactors and the craters they produce, we provide model estimates of the present-day rate at which comets impact

  12. Origin and evolution of the earth-moon system.

    NASA Technical Reports Server (NTRS)

    Alfven, H.; Arrhenius, G.

    1972-01-01

    The general problem of formation of secondary bodies around a central body is studied, and comparison is made with other satellite systems (Jupiter, Saturn, Uranus). The normal satellite systems of Neptune and the earth are reconstructed. The capture theory, the tidal evolution of the lunar orbit, destruction of a normal satellite system, asteroids and the earth-moon system, and accretion and heat structure of the moon are discussed. It is concluded that the moon originated as a planet accreted in a jet stream near the orbit of the earth, and was probably captured in a retrograde orbit.

  13. Laboratory Reference Spectroscopy of Icy Satellite Candidate Surface Materials (Invited)

    NASA Astrophysics Data System (ADS)

    Dalton, J. B.; Jamieson, C. S.; Shirley, J. H.; Pitman, K. M.; Kariya, M.; Crandall, P.

    2013-12-01

    Pitman, 2012). We will report on recent results, including spectra of sulfate hydrates, simple organic molecules, and volatile ices measured at PICL in support of past, present and planned missions. We gratefully acknowledge the support of JPL's Research and Technology Development and Strategic Hire Programs, and of the NASA Outer Planets Research and Planetary Geology and Geophysics programs. Dalton, III, J.B., Spectroscopy of icy moon surface materials, Space Sci. Rev. 153:219-247, 2010. Dalton, III, J.B., and Pitman, K.M., Low temperature optical constants of some hydrated sulfates relevant to planetary surfaces, J. Geophys. Res. 117:E09001, doi:10.1029/2011JE004036, 2012. Hapke, B.W., Bidirectional reflectance spectroscopy I. Theory, J. Geophys. Res. 86, 3039-3054, 1981. Shkuratov, Y., L. Starukhina, H. Hoffmann, and G. Arnold, A model of spectral albedo of particulate surfaces: Implications for optical properties of the Moon, Icarus 137, 235-246, 1999.

  14. Evolution of the Earth-Moon system

    NASA Technical Reports Server (NTRS)

    Touma, Jihad; Wisdom, Jack

    1994-01-01

    The tidal evolution of the Earth-Moon system is reexamined. Several models of tidal friction are first compared in an averaged Hamiltonian formulation of the dynamics. With one of these models, full integrations of the tidally evolving Earth-Moon system are carried out in the complete, fully interacting, and chaotically evolving planetary system. Classic results on the history of the lunar orbit are confirmed by our more general model. A detailed history of the obliquity of the Earth which takes into account the evolving lunar orbit is presented.

  15. Diagnosing Evaporation of Icy Planetesimals in Protoplanetary Disks

    NASA Astrophysics Data System (ADS)

    Nomura, Hideko; Ishimoto, Daiki; Nagasawa, Makiko; Tanaka, Kyoko K.; Miura, Hitoshi; Nakamoto, Taishi; Tanaka, Hidekazu; Yamamoto, Tetsuo

    2015-08-01

    It is thought that eccentricities of planetesimals are excited due to gravitational interaction with protoplanets in protoplanetary disks. As a result, bow shocks are formed around the icy planetesimals and the ice is evaporated via the shock heating. Evaporation rates and orbital evolution of such planetesimals have been investigated (Tanaka et al. 2013, Nagasawa et al. 2014). In this work, we examine a possibility of diagnosing the shock heating and evaporation of icy planetesimals, using ALMA observations of lines of molecules evaporated from the planetesimals.Evaporation of ice has been studied observationally and theoretically well, for example, at a shock front of outflows associated with young stellar objects. The evaporated molecules will be destroyed via chemical reactions with other species and/or depletion on dust grains. The evaporated molecules can survive in gas-phase for around 104years in the region hotter than their evaporation temperatures, while they freeze out immediately in the cold region. As parent species evaporated from ice, saturated nitrogen- or sulphur-bearing species and organic molecules are often considered.Our calculations show that evaporated H2S is destroyed via gas-phase reactions, and SO and then SO2 are produced via chemicalreactions. The timescale of these reactions is about 104years. Therefore, H2S and SO are good tracers of shock heating and evaporation of icy planetesimals if it occurs in the region hotter than the evaporation temperatures of H2S and SO. The evaporation temperature of SO2 is higher than those of H2S and SO.Molecular lines of H2S, SO, and SO2 have not yet been detected towards protoplanetary disks by the previous radio observations. ALMA observations with high sensitivity and high spatial resolution, however, will make it possible to detect the lines of these molecules. Conditions that molecular lines of H2S and SO becomes strong enough to be detected by ALMA observations will also be discussed.

  16. Modelling Ocean Dissipation in Icy Satellites: A Comparison of Linear and Quadratic Friction

    NASA Astrophysics Data System (ADS)

    Hay, H.; Matsuyama, I.

    2015-12-01

    Although subsurface oceans are confirmed in Europa, Ganymede, Callisto, and strongly suspected in Enceladus and Titan, the exact mechanism required to heat and maintain these liquid reservoirs over Solar System history remains a mystery. Radiogenic heating can supply enough energy for large satellites whereas tidal dissipation provides the best explanation for the presence of oceans in small icy satellites. The amount of thermal energy actually contributed to the interiors of these icy satellites through oceanic tidal dissipation is largely unquantified. Presented here is a numerical model that builds upon previous work for quantifying tidally dissipated energy in the subsurface oceans of the icy satellites. Recent semi-analytical models (Tyler, 2008 and Matsuyama, 2014) have solved the Laplace Tidal Equations to estimate the time averaged energy flux over an orbital period in icy satellite oceans, neglecting the presence of a solid icy shell. These models are only able to consider linear Rayleigh friction. The numerical model presented here is compared to one of these semi-analytical models, finding excellent agreement between velocity and displacement solutions for all three terms to the tidal potential. Time averaged energy flux is within 2-6% of the analytical values. Quadratic (bottom) friction is then incorporated into the model, replacing linear friction. This approach is commonly applied to terrestrial ocean dissipation studies where dissipation scales nonlinearly with velocity. A suite of simulations are also run for the quadratic friction case which are then compared to and analysed against recent scaling laws developed by Chen and Nimmo (2013).

  17. UV-IR Spectra of the Icy Saturnian Satellites

    NASA Astrophysics Data System (ADS)

    Hendrix, A. R.; Filacchione, G.; Schenk, P.; Clark, R. N.; Cuzzi, J. N.; Noll, K. S.; Spencer, J. R.

    2014-12-01

    Cassini's multi-instrument suite allows simultaneous observations of the icy satellites of Saturn over a wide range of wavelengths. We present composite UV-IR spectra (0.1-5 microns) of the leading and trailing hemispheres of the icy moons using data from Cassini supplemented with spectra from Hubble Space Telescope (STIS). We use data of Mimas, Enceladus, Tethys, Dione and Rhea from the Ultraviolet Imaging Spectrograph (UVIS), the Imaging Subsystem (ISS) and the Visual-Near Infrared Mapping Spectrometer (VIMS) taken during simultaneous measurements, or using similar observational geometries. The well-studied phase curve behaviors of the satellites are utilized to readily combine Earth-based STIS data with the Cassini datasets to create composite spectra. Focusing primarily on the UV-visible region so far, we find that the spectra of all satellites are bright and spectrally relatively flat at visible wavelengths longer than 500-600 nm; shortward of 500-600 nm the surfaces become absorbing with wavelength, resulting in reddish spectra. The satellites exhibit flattish-to-bowl-shaped spectra in the ~200-350 nm range and demonstrate the 165 nm water ice absorption edge, in varying strengths. These composite spectra are used to study the system-wide surface compositions of the satellites to understand large-scale exogenic effects (e.g., E-ring grain bombardment and radiolytic processing) at a variety of regolith sensing depths, and in particular to study implications for the presence and distribution of organics, ammonia, and other non-H2O-ice species in the system.

  18. Modeling Icy Saturnian Satellite Compositions Using Cryogenic Reflectance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Dalton, James B.

    2006-09-01

    Surface compositions among the icy Saturnian satellites range from nearly pure water ice at Mimas and Tethys to dark, nitrile-laced compounds at Phoebe and Dione. New measurements from the Cassini Visual and Infrared Mapping Spectrometer (VIMS) coupled with laboratory measurements of relevant compounds at cryogenic temperatures, are beginning to reveal some of the subtle variations in compounds on these worlds. By comparing spectral observations for each of these moons to the others, inferences may be drawn which help to reveal their varying formation histories. Spectral modeling of Tethys observations, for example, indicates a surface dominated by water ice with only small contributions by other materials such as carbon dioxide or amorphous carbon; yet, requires an unusual mixture of grain sizes ranging from less than ten microns to as much as 2.5 millimeters in diameter. At the other extreme, Phoebe has been shown to exhibit much clearer evidence (cf. Clark et al., 2005) for a host of compounds, including iron-bearing materials, carbon dioxide, nitriles, and organics. Comparison of Cassini VIMS spectra of Phoebe, Dione, and Hyperion indicate many of the same spectral features. Mapping of these spectral features using automated feature extraction algorithms, cryogenic laboratory reflectance measurements, and standard Hapke reflectance models allows insights into the nature and distribution of these materials on the icy Saturnian satellites. In addition, this exercise allows examination of the methods and suggests ways in which the models might be improved. These include improved formulations of phase and scattering functions, as well as laboratory investigations of both pure compounds and mixtures.

  19. Discovery of a Makemakean Moon

    NASA Astrophysics Data System (ADS)

    Parker, Alex H.; Buie, Marc W.; Grundy, Will M.; Noll, Keith S.

    2016-07-01

    We describe the discovery of a satellite in orbit about the dwarf planet (136472) Makemake. This satellite, provisionally designated S/2015 (136472) 1, was detected in imaging data collected with the Hubble Space Telescope’s Wide Field Camera 3 on UTC 2015 April 27 at 7.80 ± 0.04 mag fainter than Makemake and at a separation of 0.″57. It likely evaded detection in previous satellite searches due to a nearly edge-on orbital configuration, placing it deep within the glare of Makemake during a substantial fraction of its orbital period. This configuration would place Makemake and its satellite near a mutual event season. Insufficient orbital motion was detected to make a detailed characterization of its orbital properties, prohibiting a measurement of the system mass with the discovery data alone. Preliminary analysis indicates that if the orbit is circular, its orbital period must be longer than 12.4 days and must have a semimajor axis ≳21,000 km. We find that the properties of Makemake’s moon suggest that the majority of the dark material detected in the system by thermal observations may not reside on the surface of Makemake, but may instead be attributable to S/2015 (136472) 1 having a uniform dark surface. This “dark moon hypothesis” can be directly tested with future James Webb Space Telescope observations. We discuss the implications of this discovery for the spin state, figure, and thermal properties of Makemake and the apparent ubiquity of trans-Neptunian dwarf planet satellites.

  20. ARTEMIS Lunar Orbit Insertion and Science Orbit Design Through 2013

    NASA Technical Reports Server (NTRS)

    Broschart, Stephen B.; Sweetser, Theodore H.; Angelopoulos, Vassilis; Folta, David; Woodard, Mark

    2015-01-01

    As of late-July 2011, the ARTEMIS mission is transferring two spacecraft from Lissajous orbits around Earth-Moon Lagrange Point #1 into highly-eccentric lunar science orbits. This paper presents the trajectory design for the transfer from Lissajous orbit to lunar orbit insertion, the period reduction maneuvers, and the science orbits through 2013. The design accommodates large perturbations from Earth's gravity and restrictive spacecraft capabilities to enable opportunities for a range of heliophysics and planetary science measurements. The process used to design the highly-eccentric ARTEMIS science orbits is outlined. The approach may inform the design of future planetary moon missions.

  1. The Fatigue of Water Ice: Insight into the Tectonic Resurfacing of Tidally Deformed Icy Satellites

    NASA Astrophysics Data System (ADS)

    Hammond, N. P.; Barr, A. C.; Hirth, G.; Cooper, R. F.

    2015-12-01

    Fatigue is a process that causes materials to weaken during cyclic loading and experience brittle failure at much lower applied stresses. We perform laboratory experiments to study the fatigue behavior of water ice at conditions relevant to the surfaces of icy satellites, to test the hypothesis that the lithospheres of some icy satellites are weakened by fatigue. Many icy moons of the outer solar system, such as Europa and Enceladus, experience cyclic stresses driven by tidal forces from their parent planet. Stresses generated by tides and other physical processes, such as solid-state convection of the ice shell, are weak compared to laboratory derived yield stress values of ice. The surface geology on many icy moons, however, suggests that these processes are capable of deforming the surface, suggesting that their surfaces may have been weakened. During fatigue, microcracks slowly grow under the action of cyclic loads. Cracks grow until the stress intensity reaches a critical value and the sample fractures. The rate of microcrack growth varies with material, temperature, and loading frequency, but under most conditions the growth rate can be characterized by Paris' Law. We use a servo-hydraulic loading machine to perform cyclic 4-point bending tests on polycrystalline ice samples to measure the rate of fatigue crack growth. Ice samples are formed using the standard ice method in a sample mold with dimensions of 10x4x2 cm with an average grain size of 1.2 mm. An initial flaw is cut into the sample and loaded such that the flaw experiences the maximum tensile stress in the sample. Our initial experiments were performed at T=223 K, loading frequencies of 0.5 Hz, and stress intensities ranging from 0.3 to 0.8 of the plane-strain fracture toughness. Sample compliance is used to estimate crack length according to analytical solutions [1]. Experiments show an increase in compliance with time, consistent with substantial subcritical crack growth. Future experiments will

  2. Pluto's Spinning Moons

    NASA Video Gallery

    Most inner moons in the solar system keep one face pointed toward their central planet; this animation shows that certainly isn’t the case with the small moons of Pluto, which behave like spinning ...

  3. Kaguya Orbit Determination from JPL

    NASA Technical Reports Server (NTRS)

    Haw, Robert J.; Mottinger, N. A.; Graat, E. J.; Jefferson, D. C.; Park, R.; Menom, P.; Higa, E.

    2008-01-01

    Selene (re-named 'Kaguya' after launch) is an unmanned mission to the Moon navigated, in part, by JPL personnel. Launched by an H-IIA rocket on September 14, 2007 from Tanegashima Space Center, Kaguya entered a high, Earth-centered phasing orbit with apogee near the radius of the Moon's orbit. After 19 days and two orbits of Earth, Kaguya entered lunar orbit. Over the next 2 weeks the spacecraft decreased its apolune altitude until reaching a circular, 100 kilometer altitude orbit. This paper describes NASA/JPL's participation in the JAXA/Kaguya mission during that 5 week period, wherein JPL provided tracking data and orbit determination support for Kaguya.

  4. Origin of Martian Moons from Binary Asteroid Dissociation

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Lyons, Valerie J. (Technical Monitor)

    2001-01-01

    The origin of the Martian moons Deimos and Phobos is controversial. A common hypothesis for their origin is that they are captured asteroids, but the moons show no signs of having been heated by passage through a (hypothetical) thick martian atmosphere, and the mechanism by which an asteroid in solar orbit could shed sufficient orbital energy to be captured into Mars orbit has not been previously elucidated. Since the discovery by the space probe Galileo that the asteroid Ida has a moon 'Dactyl', a significant number of asteroids have been discovered to have smaller asteroids in orbit about them. The existence of asteroid moons provides a mechanism for the capture of the Martian moons (and the small moons of the outer planets). When a binary asteroid makes a close approach to a planet, tidal forces can strip the moon from the asteroid. Depending on the phasing, either or both can then be captured. Clearly, the same process can be used to explain the origin of any of the small moons in the solar system.

  5. The Moon's Origin.

    ERIC Educational Resources Information Center

    Cadogan, Peter

    1983-01-01

    Presents findings and conclusions about the origin of the moon, favoring the capture hypothesis of lunar origin. Advantage of the hypothesis is that it allows the moon to have been formed elsewhere, specifically in a hotter part of the solar nebula, accounting for chemical differences between earth and moon. (JN)

  6. Pluto's Intriguing Moons

    NASA Video Gallery

    We talk a lot about Charon, Pluto's largest moon that's about half the size of its host planet. But what about Pluto’s other moons? They're strange, to say the least. Pluto’s four smaller moons —...

  7. Perceptions about Moon Phases.

    ERIC Educational Resources Information Center

    Rider, Steven

    2002-01-01

    Presents research on different techniques to determine the level of understanding among middle school students regarding the phases of the moon. Quotes student responses to provide some insight into students' level of understanding of general knowledge about the moon, moon phases, and modeling the phases. Presents implications for teachers. (KHR)

  8. Look to the Moon.

    ERIC Educational Resources Information Center

    Foster, Gerald Wm.

    1996-01-01

    Presents a strategy that helps students visualize and comprehend moon phase changes through activities that use an Earth-centered point of view along with direct observations of the moon. Describes activities that parents can use at home to help children become familiar with observing moon phases. (JRH)

  9. The Earth, the Moon and Conservation of Momentum

    ERIC Educational Resources Information Center

    Brunt, Marjorie; Brunt, Geoff

    2013-01-01

    We consider the application of both conservation of momentum and Newton's laws to the Moon in an assumed circular orbit about the Earth. The inadequacy of some texts in applying Newton's laws is considered.

  10. The origin of the Martian moons revisited

    NASA Astrophysics Data System (ADS)

    Rosenblatt, Pascal

    2011-08-01

    The origin of the Martian moons, Phobos and Deimos, is still an open issue: either they are asteroids captured by Mars or they formed in situ from a circum-Mars debris disk. The capture scenario mainly relies on the remote-sensing observations of their surfaces, which suggest that the moon material is similar to outer-belt asteroid material. This scenario, however, requires high tidal dissipation rates inside the moons to account for their current orbits around Mars. Although the in situ formation scenarios have not been studied in great details, no observational constraints argue against them. Little attention has been paid to the internal structure of the moons, yet it is pertinent for explaining their origin. The low density of the moons indicates that their interior contains significant amounts of porous material and/or water ice. The porous content is estimated to be in the range of 30-60% of the volume for both moons. This high porosity enhances the tidal dissipation rate but not sufficiently to meet the requirement of the capture scenario. On the other hand, a large porosity is a natural consequence of re-accretion of debris at Mars' orbit, thus providing support to the in situ formation scenarios. The low density also allows for abundant water ice inside the moons, which might significantly increase the tidal dissipation rate in their interiors, possibly to a sufficient level for the capture scenario. Precise measurements of the rotation and gravity field of the moons are needed to tightly constrain their internal structure in order to help answering the question of the origin.

  11. Citizen Science: Mapping the Moon and Mercury

    NASA Astrophysics Data System (ADS)

    Bracey, G.; Costello, K.; Gay, P.; Reilly, E.

    2012-08-01

    The familiar face of our Moon is brought even closer to home by experiencing "Moon Zoo," an engaging online citizen science project from the creators of Galaxy Zoo. Using high-resolution images from the Lunar Reconnaissance Orbiter, Moon Zoo lets the public explore the lunar surface in breathtaking detail, mapping craters and discovering new features as they go. The maps that they generate will be used by scientists to understand solar system ages and to comparatively study geology across worlds. The less-familiar face of Mercury is also being explored and mapped through Mercury Zoo, thanks to images from MESSENGER, the first spacecraft to orbit Mercury. As citizen science projects, both of these Zoos let the public participate in authentic scientific research. This workshop offers participants the opportunity to make new and stronger connections to both of these solar system objects while getting a glimpse of the process and nature of science.

  12. Icy Collisions - Planet Building beyond the snowline

    NASA Astrophysics Data System (ADS)

    Gaertner, Sabrina; Hill, Catherine; Heisselmann, Daniel; Blum, Juergen; Fraser, Helen

    2015-11-01

    Collisions of small icy and dust particles beyond the “snow-line” are a key step in planet formation. Whilst the physical forces that underpin the aggregation of the smallest grains (van der Waals) and the largest planetessimals (gravity) are well understood, the processes involving mm - cm sized particles remain a mystery.In a unique set of experiments, we investigated low velocity collisions of dust and icy particles in this size range under microgravity conditions - utilizing parabolic flight (e.g. Salter 2009, Hill 2015 (a) & (b)). Experiments were performed at cryogenic temperatures (below 140 K) for icy aggregates and ambient as well as cryogenic temperatures (80 - 220 K) for dust aggregates.The kinetic analysis of the observed collisions of different aggregate types in different shapes and sizes revealed astonishing results - as the collisional properties of all investigated particles differ strongly from the usual assumptions in models of planet formation.Here, we present a summary of the results on the collisions of icy particles as well as first results on the collisions of dust aggregates. Focus will be on the coefficient of restitution, which measures the loss of translational energy in bouncing collisions and is a key parameter in models of planet formation.

  13. Modeling of light scattering by icy bodies

    NASA Astrophysics Data System (ADS)

    Kolokolova, L.; Mackowski, D.; Pitman, K.; Verbiscer, A.; Buratti, B.; Momary, T.

    2014-07-01

    As a result of ground-based, space-based, and in-situ spacecraft mission observations, a great amount of photometric, polarimetric, and spectroscopic data of icy bodies (satellites of giant planets, Kuiper Belt objects, comet nuclei, and icy particles in cometary comae and rings) has been accumulated. These data have revealed fascinating light-scattering phenomena, such as the opposition surge resulting from coherent backscattering and shadow hiding and the negative polarization associated with them. Near-infrared (NIR) spectra of these bodies are especially informative as the depth, width, and shape of the absorption bands of ice are sensitive not only to the ice abundance but also to the size of icy grains. Numerous NIR spectra obtained by Cassini's Visual and Infrared Mapping Spectrometer (VIMS) have been used to map the microcharacteristics of the icy satellites [1] and rings of Saturn [2]. VIMS data have also permitted a study of the opposition surge for icy satellites of Saturn [3], showing that coherent backscattering affects not only brightness and polarization of icy bodies but also their spectra [4]. To study all of the light-scattering phenomena that affect the photopolarimetric and spectroscopic characteristics of icy bodies, including coherent backscattering, requires computer modeling that rigorously considers light scattering by a large number of densely packed small particles that form either layers (in the case of regolith) or big clusters (ring and comet particles) . Such opportunity has appeared recently with a development of a new version MSTM4 of the Multi-Sphere T-Matrix code [5]. Simulations of reflectance and absorbance spectra of a ''target'' (particle layer or cluster) require that the dimensions of the target be significantly larger than the wavelength, sphere radius, and layer thickness. For wavelength-sized spheres and packing fractions typical of regolith, targets can contain dozens of thousands of spheres that, with the original MSTM

  14. Conference on the Origin of the Moon

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Various topics relating to lunar evolution are discussed. The Moon's ancient orbital history, geophysical and geochemical constraints favoring the capture hypothesis, the site of the lunar core, chemical and petrological constraints, dynamical constraints, and mathematical models are among the topics discussed.

  15. Galileo's Medicean Moons (IAU S269)

    NASA Astrophysics Data System (ADS)

    Barbieri, Cesare; Chakrabarti, Supriya; Coradini, Marcello; Lazzarin, Monica

    2010-11-01

    Preface; 1. Galileo's telescopic observations: the marvel and meaning of discovery George V. Coyne, S. J.; 2. Popular perceptions of Galileo Dava Sobel; 3. The slow growth of humility Tobias Owen and Scott Bolton; 4. A new physics to support the Copernican system. Gleanings from Galileo's works Giulio Peruzzi; 5. The telescope in the making, the Galileo first telescopic observations Alberto Righini; 6. The appearance of the Medicean Moons in 17th century charts and books. How long did it take? Michael Mendillo; 7. Navigation, world mapping and astrometry with Galileo's moons Kaare Aksnes; 8. Modern exploration of Galileo's new worlds Torrence V. Johnson; 9. Medicean Moons sailing through plasma seas: challenges in establishing magnetic properties Margaret G. Kivelson, Xianzhe Jia and Krishan K. Khurana; 10. Aurora on Jupiter: a magnetic connection with the Sun and the Medicean Moons Supriya Chakrabarti and Marina Galand; 11. Io's escaping atmosphere: continuing the legacy of surprise Nicholas M. Schneider; 12. The Jovian Rings Wing-Huen Ip; 13. The Juno mission Scott J. Bolton and the Juno Science Team; 14. Seeking Europa's ocean Robert T. Pappalardo; 15. Europa lander mission: a challenge to find traces of alien life Lev Zelenyi, Oleg Korablev, Elena Vorobyova, Maxim Martynov, Efraim L. Akim and Alexander Zakahrov; 16. Atmospheric moons Galileo would have loved Sushil K. Atreya; 17. The study of Mercury Louise M. Prockter and Peter D. Bedini; 18. Jupiter and the other giants: a comparative study Thérèse Encrenaz; 19. Spectroscopic and spectrometric differentiation between abiotic and biogenic material on icy worlds Kevin P. Hand, Chris McKay and Carl Pilcher; 20. Other worlds, other civilizations? Guy Consolmagno, S. J.; 21. Concluding remarks Roger M. Bonnet; Posters; Author index; Object index.

  16. A proposed space mission around the Moon to measure the Moon Radio-Quiet Zone

    NASA Astrophysics Data System (ADS)

    Antonietti, N.; Pagana, G.; Pluchino, S.; Maccone, C.

    In a series of papers published since 2000 mainly in Acta Astronautica the senior author Maccone dealt with the advantages of the Farside of the Moon for future utilization Clearly the Moon Farside is free from RFI Radio Frequency Interference produced in larger and larger amounts by the increasing human exploitation of radio technologies That author suggested that crater Daedalus located at the center of the Farside was the best possible location to build up in the future one or more radiotelescopes or phased arrays to achieve the maximum sensitivity in radioastronomical and SETI searches Also a radio-quiet region of space above the Farside of the Moon exists and is called the Quiet Cone The Quiet Cone actual size however is largely unknown since it depends on the orbits of radio-emitting satellites around the Earth that are themselves largely unknown due to the military involvements In addition diffraction of electromagnetic waves grazing the surface of the Moon causes further changes in the geometrical shape of the Quiet Cone This riddle can be solved only by direct measurements of the radio attenuation above the Farside of the Moon performed by satellites orbiting the Moon itself In this paper we propose to let one or more low cost radiometers be put into orbit around the Moon to measure the RFI attenuation at different frequencies and altitudes above the Moon The opportunity of adding more payload s such as an ion detector and or a temperature sensor is evaluated also In this regard we present in this paper the experience gained by

  17. Thickness Constraints on the Icy Shells of the Galilean Satellites from a Comparison of Crater Shapes

    NASA Technical Reports Server (NTRS)

    Schenk, Paul M.

    2002-01-01

    A thin outer ice shell on Jupiter's large moon Europa would imply easy exchange between the surface and any organic or biotic material in its putative subsurface ocean. The thickness of the outer ice shell is poorly constrained, however, with model-dependent estimates ranging from a few kilometers of depths of impact craters on Europa, Ganymede and Callisto that reveal two anomalous transitions in crater shape with diameter. The first transition is probably related to temperature-dependent ductility of the crust at shallow depths (7-8 km on Europa). The second transition is attributed to the influence of subsurface oceans on all three satellites, which constrains Europa's icy shell to be at least 19 km thick. The icy lithospheres of Ganymede and Callisto are equally ice-rich, but Europa's icy shell has a thermal structure about 0.25-0.5 times the thickness of Ganymede's or Callisto's shells, depending on epoch. The appearances of the craters on Europa are inconsistent with thin-ice-shell models and indicate that exchange of oceanic and surface material could be difficult.

  18. Smart-1 Moon Impact Operations

    NASA Technical Reports Server (NTRS)

    Ayala, Andres; Rigger, Ralf

    2007-01-01

    This paper describes the operations to control the Moon impact of the 3-axis stabilized spacecraft SMART-1 in September 2006. SMART-1 was launched on 27/09/2003. It was the first ESA mission to use an Electric Propulsion (EP) engine as the main motor to spiral out of the Earth gravity field and reach a scientific moon orbit [1]. During September 2005 the last EP maneuvers were performed using the remaining Xenon, in order to compensate for the 3rd body perturbations of the Sun and Earth. These operations extended the mission for an additional year. Afterwards the EP performance became unpredictable and low, so that no meaningful operation for the moon impact could be done. To move the predicted impact point on the 16/8/2006 into visibility from Earth an alternative Delta-V strategy was designed. Due to their alignment, the attitude thrusters could not be used directly to generate the Delta-V, so this strategy was based on controlled angular momentum biasing. Firing along the velocity vector around apolune, the remaining Hydrazine left from the attitude control budget was used, to shift the impact to the required coordinates.

  19. Unveiling the evolution and formation of icy giants

    NASA Astrophysics Data System (ADS)

    Dirkx, D.; Bocanegra, T.; Bracken, C.; Costa, M.; Gerth, I.; Konstantinidis, K.; Labrianidis, C.; Laneuville, M.; Luntzer, A.; MacArthur, J.; Maier, A.; Morschhauser, A.; Nordheim, T.; Sallantin, R.; Tlustos, R.

    2013-09-01

    The planet Uranus is one of two ice giants in the solar system, both of which have only been visited only once by the Voyager 2 spacecraft. Ice giants represent a fundamental class of planet, and in fact, many known exoplanets fall in this category. Therefore, a dedicated mission to an ice giant is crucial to deepen our understanding of the formation, evolution and current characteristics of such planetary and exoplanetary systems. Here we present the results of a detailed study of a mission to investigate the Uranus system as an archetype for ice giants. Our detailed trade-off study has resulted in a mission configuration consisting of an orbiter with a deep atmospheric probe and an extensive orbital tour of the main moons of the Uranus system.

  20. Water Ice Lines and the Formation of Giant Moons around Super-Jovian Planets

    NASA Astrophysics Data System (ADS)

    Heller, René; Pudritz, Ralph

    2015-06-01

    Most of the exoplanets with known masses at Earth-like distances to Sun-like stars are heavier than Jupiter, which raises the question of whether such planets are accompanied by detectable, possibly habitable moons. Here we simulate the accretion disks around super-Jovian planets and find that giant moons with masses similar to Mars can form. Our results suggest that the Galilean moons formed during the final stages of accretion onto Jupiter, when the circumjovian disk was sufficiently cool. In contrast to other studies, with our assumptions, we show that Jupiter was still feeding from the circumsolar disk and that its principal moons cannot have formed after the complete photoevaporation of the circumsolar nebula. To counteract the steady loss of moons into the planet due to type I migration, we propose that the water ice line around Jupiter and super-Jovian exoplanets acted as a migration trap for moons. Heat transitions, however, cross the disk during the gap opening within ≈104 years, which makes them inefficient as moon traps and indicates a fundamental difference between planet and moon formation. We find that icy moons larger than the smallest known exoplanet can form at about 15-30 Jupiter radii around super-Jovian planets. Their size implies detectability by the Kepler and PLATO space telescopes as well as by the European Extremely Large Telescope. Observations of such giant exomoons would be a novel gateway to understanding planet formation, as moons carry information about the accretion history of their planets.

  1. Condensing the Moon from a MAD Earth

    NASA Astrophysics Data System (ADS)

    Lock, S. J.; Stewart, S. T.; Petaev, M. I.; Leinhardt, Z. M.; Mace, M.; Jacobsen, S. B.; Cuk, M.

    2015-12-01

    The favored theory for lunar origin is the giant impact hypothesis, where a protoplanet collides with the growing Earth and creates an orbiting disk of material that forms the Moon. However, the astonishing isotopic similarity between the Earth and Moon cannot be explained by current giant impact models without appealing to highly specific circumstances. Here, we demonstrate that a condensation model for lunar origin, achieved via a previously unrecognized class of post-impact states, produces the Moon's major characteristics. The required class of post-impact states is defined by (i) a high degree of vaporization and (ii) rapid rotation. When these two criteria are met, the mantle, atmosphere and disk (MAD) form a dynamically and thermodynamically continuous structure that quickly mixes, thereby diluting initial compositional heterogeneities. Then, partial condensation from the pressure-supported mass beyond the Roche limit produces a Moon that is isotopically similar to the bulk silicate Earth and depleted in volatile and moderately volatile elements. Initially, the condensed liquid is composed of silicates. As the structure cools, metal exsolves in the accreting Moon and moonlets. We calculate ~2wt% metal is exsolved from a bulk silicate Earth composition, which is consistent with estimates of the mass of the lunar core. Thus, similar tungsten isotopes are established in the Earth and Moon as metal is exsolved in both bodies after mixing. In our model, the criterion for lunar origin shifts, away from specific impact parameters that inject terrestrial material into orbit, to any collision that transforms the Earth into a rapidly rotating and substantially vaporized MAD planet. Impacts that can transform the Earth are common during the end stages of planet formation. Therefore, the characteristics of our Moon are a natural consequence of forming the Earth.

  2. Observing the new Moon

    NASA Astrophysics Data System (ADS)

    Hoffman, Roy E.

    2003-04-01

    The first appearance of the new Moon has been used throughout history and is still used today to determine religious calendars. Many methods for predicting the Moon's appearance have been proposed throughout history and new models are still being developed. All these models have to be tested against observations to test their validity. To this end, ancient and modern astronomers have collected observations of new and old crescent Moons. Here we present the results of 539 observations of the Moon made over several years by many experienced observers in good weather conditions. In addition to determining whether or not the Moon was seen, the times of its first and last appearance were also carefully recorded. The addition of the appearance time means that even an easily visible Moon, recorded when it can barely be seen, may be compared with a visibility criterion. The observational data base greatly expands on previously published reports.

  3. Atmospheric/Exospheric Characteristics of Icy Satellites

    NASA Astrophysics Data System (ADS)

    Coustenis, A.; Tokano, T.; Burger, M. H.; Cassidy, T. A.; Lopes, R. M.; Lorenz, R. D.; Retherford, K. D.; Schubert, G.

    2010-06-01

    The atmospheres/exospheres of icy satellites greatly vary from one to the next in terms of density, composition, structure or steadiness. Titan is the only icy satellite with a dense atmosphere comparable in many ways to that of the Earth’s atmosphere. Titan’s atmosphere prevents the surface from direct interaction with the plasma environment, but gives rise to Earth-like exchanges of energy, matter and momentum. The atmospheres of other satellites are tenuous. Enceladus’ atmosphere manifests itself in a large water vapor plume emanating from surface cracks near the south pole. Io’s SO2 atmosphere originates from volcanoes. Europa’s tenuous O2 atmosphere is produced by intense radiation bombardment. This chapter reviews the characteristics of the atmospheres of Titan, Enceladus, Io and Europa based on observations.

  4. Thermal Conductivity Measurements on Icy Satellite Analogs

    NASA Technical Reports Server (NTRS)

    Javeed, Aurya; Barmatz, Martin; Zhong, Fang; Choukroun, Mathieu

    2012-01-01

    With regard to planetary science, NASA aspires to: "Advance scientific knowledge of the origin and history of the solar system, the potential for life elsewhere, and the hazards and resources present as humans explore space". In pursuit of such an end, the Galileo and Cassini missions garnered spectral data of icy satellite surfaces implicative of the satellites' structure and material composition. The potential for geophysical modeling afforded by this information, coupled with the plausibility of life on icy satellites, has pushed Jupiter's Europa along with Saturn's Enceladus and Titan toward the fore of NASA's planetary focus. Understanding the evolution of, and the present processes at work on, the aforementioned satellites falls squarely in-line with NASA's cited goal.

  5. The Moon in the UV

    NASA Astrophysics Data System (ADS)

    Hendrix, Amanda

    2014-11-01

    While the Moon has been observed in the UV for decades, the real utility of this spectral region for unlocking some of the Moon’s secrets has only recently been understood. Previously the domain of atmospheric studies, the UV has now emerged as an important spectral region for studying surfaces. The ultraviolet regime is very sensitive to both space weathering effects and composition, including hydration. This presentation will cover a review of early UV lunar observations (e.g., Apollo 17, International Ultraviolet Explorer), as well as early laboratory studies that first shone a light on the importance of this spectral region. The Lyman Alpha Mapping Project (LAMP) instrument, currently in orbit on the Lunar Reconnaissance Orbiter (LRO) spacecraft, is providing critical mapping capabilities of UV signatures, including signals from the permanently shadowed regions of the poles. I will discuss some of these exciting results, and extend these to implications for other airless bodies in the solar system.

  6. Moon Farside, Quiet Cone and the "RLI" Experiment

    NASA Astrophysics Data System (ADS)

    Maccone, C.

    The Farside of the Moon is a unique place. Radio emissions coming from the Earth, and notably the from Telecommunication Satellites orbiting the Earth, don't get there since shielded by the Moon's spherical body. A radio telescope placed inside Crater Daedalus (just at the center of the Farside) would thus sense no man-made RFI (Radio Frequency Interference) and would be ideal for all radio astronomical and SETI searches. Above the Farside, a conical region extends into space, the ``Quiet Cone'', tangent to the Moon surface and with apex a few thousands of kilometers above the Moon. The size of the Quiet Cone, however, is only vaguely known, and changes in time, because the orbits of secret military satellites around the Earth are of course unknown. The only way to know the current, actual size of the Quiet Cone is to send a radiometer into orbit around the Moon and find out where the RFI coming from the Earth is actually shielded and where it is not. The RLI Experiment (RLI is an acronym for ``Radiometro Lunare Italiano'', i.e. Italian Moon Radiometer), is currently under construction by an Italian team coordinated by this author as Principal Investigator. The RLI is hopefully going to be put into orbit around the Moon before 2007. This will be done by placing the RLI radiometer aboard the ``Trailbalzer'', the first American commercial Moon spacecraft, built by TransOrbital Inc.. The RLI Experiment will take direct measurements of the intensity of man-made RFI around two frequencies: The band in between 10.7 and 11.8 GHz (main frequency band of European TV transmissions and, in part, also of American TV transmissions) and The band in between 10 Hz and 10 kHz, to get a Fourier spectrum of the very thin Moon atmosphere. A scientific and technical description of the RLI mission is given in this paper.

  7. On the possibility of a 'cuckoo-effect' in the earth-moon system

    NASA Astrophysics Data System (ADS)

    Pauwels, T.

    In this paper an investigation is made of the possibility that the moon could have depleted the earth satellite system of all natural satellites by a combination of orbit-orbit resonances and tidal evolution. Simulations show that for a satellite closer than 150 earth radii, avoiding all resonances is definitely impossible, but it can be captured in a stable resonant orbit as well as in a resonant orbit leading to a close approach to the moon.

  8. Distinct Aqueous and Hydrocarbon Cryovolcanism on Titan and Other Icy Satellites (Invited)

    NASA Astrophysics Data System (ADS)

    Kargel, J. S.; Furfaro, R.; Candelaria, P.

    2010-12-01

    Almost as soon as low-temperature solar nebula condensation sequences were first computed, it was realized that icy satellites have an internal heat source in long-lived radioactivities and could undergo differentiation; furthermore, freezing-point depressants, such as ammonia, and apolar gases, such as methane, could enable icy satellites to undergo aqueous cryovolcanism. The subsequent recognition of tidal and gravitational potential energy sources increased expectations for cryovolcanism. Voyager imaging and discovery of apparent cryovolcanic landforms—best exhibited by Triton, more ambiguous elsewhere-- motivated studies of the phase relations, phase densities and other thermodynamic properties, solid- and liquid-state rheologies, and possible cryovolcanic eruptive behaviors and landform characteristics. Ironically, the closer we examined Jovian icy moons with Galileo, the rarer cryovolcanic landforms appeared to be, with only a few compelling and very well characterized cases found mainly on Europa. Compelling examples of effusive cryovolcanism mainly occupied local topographic lows, whereas cases not in low spots tended to exhibit signs of explosive emplacement. Spectacular evidence of explosive cryovolcanism or geyser-like behavior was found by Cassini on Enceladus, but most other icy Saturnian moons did not reveal any compelling indicators of eruptions. Titan has so far been a mixed case, where some indicators of cryovolcanism have been reported, but there is scant compelling evidence for the process. We think that the sparseness of compelling effusive cryovolcanic features on icy satellites is because free, unreacted ammonia is less common than previously thought, and the main aqueous liquids are salt-water solutions denser than ice I; hence, they tend not to erupt, or they erupt only if driven by gas exsolution; even then, a thin ice shell and high heat flow is needed to allow aqueous liquids near enough to the surface to erupt. On satellites with thick

  9. Space Environmental Erosion of Polar Icy Regolith

    NASA Technical Reports Server (NTRS)

    Farrell, William M.; Killen, R. M.; Vondrak, R. R.; Hurley, D. M.; Stubbs, T. J.; Delory, G. T.; Halekas, J. S.; Zimmerman, M. I.

    2011-01-01

    While regions at the floors of permanently shadowed polar craters are isolated from direct sunlight, these regions are still exposed to the harsh space environment, including the interplanetary Lyman-a background, meteoric impacts, and obstacle-affected solar wind. We demonstrate that each of these processes can act to erode the polar icy regolith located at or near the surface along the crater floor. The Lyman-a background can remove/erode the icy-regolith via photon stimulated desorption [1], meteoric impacts can vaporize the regolith [2], and redirected solar wind ions can sputter the ice-regolith mix [3]. As an example we shall examine in detail the inflow of solar wind ions and electrons into polar craters, One might expect such ions to flow horizontally over the crater top (see Figure). However, we find that plasma ambipolar processes act to deflect passing ions into the craters [3]. We examine this plasma process and determine the ion flux as a function of position across a notional crater floor. We demonstrate that inflowing solar wind ions can indeed create sputtering along the crater floor, effectively eroding the surface. Erosion time scales rrom sputtering will be presented. We shall also consider the effect of impact vaporization on buried icy-regolith regions. There will also be a discussion of solar wind electrons that enter into the PSR, demonstrating that these also have the ability rree surface-bound atoms via electron stimulated desorption processes [l].

  10. Martian Moon Eclipses Sun, in Stages

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This panel illustrates the transit of the martian moon Phobos across the Sun. It is made up of images taken by the Mars Exploration Rover Opportunity on the morning of the 45th martian day, or sol, of its mission. This observation will help refine our knowledge of the orbit and position of Phobos. Other spacecraft may be able to take better images of Phobos using this new information. This event is similar to solar eclipses seen on Earth in which our Moon passes in front of the Sun. The images were taken by the rover's panoramic camera.

  11. Laboratory permittivity measurements of icy planetary analogs in the millimeter and submillimeter domains, in relation with JUICE mission.

    NASA Astrophysics Data System (ADS)

    Brouet, Y.; Jacob, K.; Murk, A.; Poch, O.; Pommerol, A.; Thomas, N.; Levasseur-Regourd, A. C.

    2015-12-01

    The European Space Agency's JUpiter ICy moons Explorer (JUICE) spacecraft is planned for launch in 2022 and arrival at Jupiter in 2030. It will observe the planet Jupiter and three of its largest moons, Ganymede, Callisto and Europa. One instrument on the JUICE spacecraft is the Sub-millimeter Wave Instrument (SWI), which will measure brightness temperatures from Jupiter's stratosphere and troposphere, and from subsurfaces of Jupiter's icy moons. In the baseline configuration SWI consists of two tunable sub-millimeter wave receivers operating from 530 to 625 GHz. As an alternative one of the receivers could cover the range of 1080 and 1275 GHz. Inversion models are strongly dependent on the knowledge of the complex relative permittivity (hereafter permittivity) of the target material to retrieve the physical properties of the subsurface (e.g. [1][2]). We set up a laboratory experiment allowing us to perform reproducible measurements of the complex scattering parameters S11 and S21 in the ranges of 70 to 110 GHz, of 100 to 160 GHz, of 140 to 220 GHz, of 140 to 220 GHz and of 510 to 715 GHz. These scattering parameters can be used to retrieve the permittivity of icy analogs of the surfaces and subsurfaces of Jupiter's icy moons in order to prepare the data interpretation of SWI [3]. The measurements are performed under laboratory conditions with a quasi-optical bench (Institute of Applied Physics, University of Bern). The icy analogs that we prepare in the Laboratory for Outflow Studies of Sublimating Materials (LOSSy, Physics Institute, University of Bern), include two different porous water ice samples composed of fine-grained ice particles with a size range of 4 to 6 microns and ice particles with a size range of 50 to 100 microns [4][5]; and possibly CO2 ice. We will present the general experimental set-up and the first results in the context to prepare the data interpretation of SWI. [1] Ulaby, F. T., Long, D. G., 2014. Microwave radar and radiometric remote

  12. ON THE DYNAMICS AND ORIGIN OF HAUMEA'S MOONS

    SciTech Connect

    Ćuk, Matija; Ragozzine, Darin; Nesvorný, David

    2013-10-01

    The dwarf planet Haumea has two large satellites, Namaka and Hi'iaka, which orbit at relatively large separations. Both moons have significant eccentricities and inclinations in a pattern that is consistent with a past orbital resonance. Based on our analysis, we find that the present system is not consistent with satellite formation close to the primary and tidal evolution through mean-motion resonances. We propose that Namaka experienced only limited tidal evolution, leading to the mutual 8:3 mean-motion resonance which redistributed eccentricities and inclinations between the moons. This scenario requires that the original orbit of Hi'iaka was mildly eccentric; we propose that this eccentricity was either primordial or acquired through encounters with other trans-Neptunian objects. Both dynamical stability and our preferred tidal evolution model imply that the moons' masses are only about one-half of previously estimated values, suggesting high albedos and low densities. Because the present orbits of the moons strongly suggest formation from a flat disk close to their present locations, we conclude that Hi'iaka and Namaka may be second-generation moons, formed after the breakup of a larger past moon, previously proposed as the parent body of the Haumea family. We derive plausible parameters of that moon, consistent with the current models of Haumea's formation. An interesting implication of this hypothesis is that Hi'iaka and Namaka may orbit retrograde with respect to Haumea's spin. Retrograde orbits of Haumea's moons would be in full agreement with available observations and our dynamical analysis, and could provide a unique confirmation of the ''disrupted satellite'' scenario for the origin of the family.

  13. A Holographic Microscope for Detection of Microorganisms on Icy Worlds

    NASA Astrophysics Data System (ADS)

    Lindensmith, C. A.; Nadeau, J. L.; Deming, J. W.; Showalter, G. M.; Rider, S.; Bedrossian, M.

    2015-12-01

    Holography is a well-established imaging technique that uses the interference of light to record and reproduce three-dimensional images of objects. Its use began in the 1960s with the invention of the laser. Digital holographic microscopy (DHM) has several advantages over ordinary imaging microscopy which make it ideal for field and astrobiology use, including no need for focus or scanning so that instruments are readily made autonomous. DHM can produce simultaneous bright-field and quantitative phase-contrast images of the same field, providing additional information about transparent objects, e.g., refractive index and/or thickness; thus it inherently supports effective label-free imaging. We have built a fieldable DHM for detection of microorganisms in bodies of water and in brines collected from sea ice. Ice that appears solid to the eye contains interconnected brine-filled microscopic pores and veins which are occupied by populations of prokaryotes and eukaryotes. The presence of life in "solid" ice has important implications for exploration of icy worlds, where it is unlikely that the first missions will be able to access the subsurface oceans. Using this new instrument, we examined several dozen samples from three different sites around Nuuk, Greenland. In all samples, mixed populations of both prokaryotic and eukaryotic microorganisms were observed. Many of the organisms were motile immediately upon extraction from sea ice, and others became motile after warming or addition of sugars and/or amino acids. Meaningful motility was readily distinguished from turbulence or fluid flow. The spatial resolution of the instrument was better than 1 μm, leading to unambiguous recognition of subcellular structures in eukaryotes, including nuclei and chloroplasts. We present mission scenrios for both orbiters and landers in which DHM may be used as a valuable complement to chemical-based life detection techniques for discovery of cellular life on icy worlds.

  14. Bodily tides near spin-orbit resonances

    NASA Astrophysics Data System (ADS)

    Efroimsky, Michael

    2012-03-01

    Spin-orbit coupling can be described in two approaches. The first method, known as the "MacDonald torque", is often combined with a convenient assumption that the quality factor Q is frequency-independent. This makes the method inconsistent, because derivation of the expression for the MacDonald torque tacitly fixes the rheology of the mantle by making Q scale as the inverse tidal frequency. Spin-orbit coupling can be treated also in an approach called "the Darwin torque". While this theory is general enough to accommodate an arbitrary frequency-dependence of Q, this advantage has not yet been fully exploited in the literature, where Q is often assumed constant or is set to scale as inverse tidal frequency, the latter assertion making the Darwin torque equivalent to a corrected version of the MacDonald torque. However neither a constant nor an inverse-frequency Q reflect the properties of realistic mantles and crusts, because the actual frequency-dependence is more complex. Hence it is necessary to enrich the theory of spin-orbit interaction with the right frequency-dependence. We accomplish this programme for the Darwin-torque-based model near resonances. We derive the frequency-dependence of the tidal torque from the first principles of solid-state mechanics, i.e., from the expression for the mantle's compliance in the time domain. We also explain that the tidal torque includes not only the customary, secular part, but also an oscillating part. We demonstrate that the lmpq term of the Darwin-Kaula expansion for the tidal torque smoothly passes zero, when the secondary traverses the lmpq resonance (e.g., the principal tidal torque smoothly goes through nil as the secondary crosses the synchronous orbit). Thus, we prepare a foundation for modeling entrapment of a despinning primary into a resonance with its secondary. The roles of the primary and secondary may be played, e.g., by Mercury and the Sun, correspondingly, or by an icy moon and a Jovian planet. We also

  15. Lunar Prospector Orbit Determination Results

    NASA Technical Reports Server (NTRS)

    Beckman, Mark; Concha, Marco

    1998-01-01

    The orbit support for Lunar Prospector (LP) consists of three main areas: (1) cislunar orbit determination, (2) rapid maneuver assessment using Doppler residuals, and (3) routine mapping orbit determination. The cislunar phase consisted of two trajectory correction maneuvers during the translunar cruise followed by three lunar orbit insertion burns. This paper will detail the cislunar orbit determination accuracy and the real-time assessment of the cislunar trajectory correction and lunar orbit insertion maneuvers. The non-spherical gravity model of the Moon is the primary influence on the mapping orbit determination accuracy. During the first two months of the mission, the GLGM-2 lunar potential model was used. After one month in the mapping orbit, a new potential model was developed that incorporated LP Doppler data. This paper will compare and contrast the mapping orbit determination accuracy using these two models. LP orbit support also includes a new enhancement - a web page to disseminate all definitive and predictive trajectory and mission planning information. The web site provides definitive mapping orbit ephemerides including moon latitude and longitude, and four week predictive products including: ephemeris, moon latitude/longitude, earth shadow, moon shadow, and ground station view periods. This paper will discuss the specifics of this web site.

  16. CIRCUMBINARY CHAOS: USING PLUTO'S NEWEST MOON TO CONSTRAIN THE MASSES OF NIX AND HYDRA

    SciTech Connect

    Youdin, Andrew N.; Kratter, Kaitlin M.; Kenyon, Scott J.

    2012-08-10

    The Pluto system provides a unique local laboratory for the study of binaries with multiple low-mass companions. In this paper, we study the orbital stability of P4, the most recently discovered moon in the Pluto system. This newfound companion orbits near the plane of the Pluto-Charon (PC) binary, roughly halfway between the two minor moons Nix and Hydra. We use a suite of few body integrations to constrain the masses of Nix and Hydra, and the orbital parameters of P4. For the system to remain stable over the age of the solar system, the masses of Nix and Hydra likely do not exceed 5 Multiplication-Sign 10{sup 16} kg and 9 Multiplication-Sign 10{sup 16} kg, respectively. These upper limits assume a fixed mass ratio between Nix and Hydra at the value implied by their median optical brightness. Our study finds that stability is more sensitive to their total mass and that a downward revision of Charon's eccentricity (from our adopted value of 0.0035) is unlikely to significantly affect our conclusions. Our upper limits are an order of magnitude below existing astrometric limits on the masses of Nix and Hydra. For a density at least that of ice, the albedos of Nix and Hydra would exceed 0.3. This constraint implies they are icy, as predicted by giant impact models. Even with these low masses, P4 only remains stable if its eccentricity e {approx}< 0.02. The 5:1 commensurability with Charon is particularly unstable, combining stability constraints with the observed mean motion places the preferred orbit for P4 just exterior to the 5:1 resonance. These predictions will be tested when the New Horizons satellite visits Pluto. Based on the results for the PC system, we expect that circumbinary, multi-planet systems will be more widely spaced than their singleton counterparts. Further, circumbinary exoplanets close to the three-body stability boundary, such as those found by Kepler, are less likely to have other companions nearby.

  17. Phoebe and the Icy Saturnian Satellites: Implications for Satellite Origins

    NASA Astrophysics Data System (ADS)

    Mosqueira, I.; Estrada, P. R.

    2004-11-01

    Phoebe's retrograde, eccentric and inclined orbit marks it as an object captured from heliocentric orbit. Accordingly, its composition may be indicative of its origin in the solar nebula. Analogous arguments have been made extensively in connection with the origin of Pluto-Charon (see, e.g., McKinnon et al. 1997) as well as Triton (McKinnon and Mueller 1989). Indeed, the demarcation between nebula and subnebula objects has led a number of workers (see, e.g., Johnson et al. 1987; Lunine et al. 1993; Podolak et al. 1993) to argue that the regular satellites of the giant planets did not derive the bulk of their material directly from heliocentric orbit. The recent Cassini flyby of Phoebe has yielded a mass for this object of GM = 0.5527 ± 0.001 km3/s2 Jacobson et al. 2004 (this conference). Its density of 1.6 g/cm3 indicates a rock to ice ratio of at least 50 % (Porco et al. 2004; Science, to be submitted). Phoebe's high rock/ice ratio when compared to the icy Saturnian satellites reinforces the argument that Phoebe is an object that formed in heliocentric orbit and became captured. Yet, given that it may be misleading to lump together satellites with quite different formation histories, we refine the comparison on the basis of models for regular satellite formation. Because it derives condensables directly from heliocentric orbit and fails to consider planetesimals, the model of Canup and Ward (2002) does not provide a context for understanding such compositional differences. We will therefore discuss two models of satellite formation we are developing, which differ mainly in their treatment of turbulence (decaying vs steady). In both models the inner (located inside Titan's orbit), icy Saturnian satellites represent a second generation of objects. Mosqueira and Estrada (2003a,b) has these satellites forming 104-10^5 years after Titan as the disk became optically thin and water rich due to preferential gas drag loss of silicates as Saturn cooled. On the other hand

  18. Phoebe and the Icy Saturnian Satellites: Implications for Satellite Origins

    NASA Astrophysics Data System (ADS)

    Mosqueira, I.; Estrada, P. R.

    2004-12-01

    Phoebe's retrograde, eccentric and inclined orbit marks it as an object captured from heliocentric orbit. Accordingly, its composition may be indicative of its origin in the solar nebula. Analogous arguments have been made extensively in connection with the origin of Pluto-Charon (see, e.g., McKinnon et al. 1997) as well as Triton (McKinnon and Mueller 1989). Indeed, the demarcation between nebula and subnebula objects has led a number of workers (see, e.g., Johnson et al. 1987; Lunine et al. 1993; Podolak et al. 1993) to argue that the regular satellites of the giant planets did not derive the bulk of their material directly from heliocentric orbit. The recent Cassini flyby of Phoebe has yielded a mass for this object of GM = 0.5527 ± 0.001 km3/s2 Jacobson et al. 2004. Its density of 1.6 g/cm3 indicates a rock to ice ratio of at least 50 % (Porco et al. 2004; Science, to be submitted). Phoebe's high rock/ice ratio when compared to the icy Saturnian satellites reinforces the argument that Phoebe is an object that formed in heliocentric orbit and became captured. Yet, given that it may be misleading to lump together satellites with quite different formation histories, we refine the comparison on the basis of models for regular satellite formation. Because it derives condensables directly from heliocentric orbit and fails to consider planetesimals, the model of Canup and Ward (2002) does not provide a context for understanding such compositional differences. We will therefore discuss two models of satellite formation we are developing, which differ mainly in their treatment of turbulence (decaying vs steady). In both models the inner (located inside Titan's orbit), icy Saturnian satellites represent a second generation of objects. Mosqueira and Estrada (2003a,b) has these satellites forming 104-10^5 years after Titan as the disk became optically thin and water rich due to preferential gas drag loss of silicates as Saturn cooled. On the other hand, the gas

  19. New `Moons' of Saturn May Be Transient Objects

    NASA Astrophysics Data System (ADS)

    1996-01-01

    ADONIS Observes Pandora, S/1995 S6 and Others How many moons has Saturn, the second-largest planet in the solar system ? Until recently, the best answer was eighteen, ranging from innermost Pan that circles the planet 75,000 km above the cloud tops in a little less than 14 hours, to distant Phoebe , 13 million km away in a reverse (`retrograde') 550-day orbit [1]. Now the situation is less clear. New observations have become available which raise some questions about the actual number and nature of small `moons' near this planet. In particular, there is now evidence that some of the recent sightings may in fact refer to temporary condensations of material (dust clouds) in the inner rings rather than solid bodies. Most of these observations have been made with the Hubble Space Telescope (HST), but important supplementary data [2] was also obtained with the high-resolution ADONIS camera at the ESO 3.6-m telescope. When the Sun and Earth Cross the Plane of the Rings Saturn is surrounded by a spectacular ring system in which a large number of small (probably cm- to m-size) icy bodies are moving. Soon after the invention of the telescope in the early 17th century, it was found to consist of an inner B- and an outer A-ring, separated by the dark `Cassini division'. The faint F-ring was discovered further out by the Pioneer 11 spacecraft in 1979; it is separated from the A-ring by the 3000-km wide `Pioneer division'. All of these rings are very flat and quite thin. They are apparently no more than 2 kilometres thick in a global sense, and probably much less locally (10 - 100 metres). They all lie in the same plane which is inclined by 26.7 degrees, relative to the planet's orbital plane. One revolution of Saturn around the Sun lasts 29.455 years and twice during each orbital period, i.e. once about every 15 years, the Sun is situated exactly in this ring plane. This happened most recently on November 19, 1995. Astronomers refer to these relatively rare events as solar

  20. China targets the Moon

    NASA Astrophysics Data System (ADS)

    2011-08-01

    China has already launched two spacecraft to the Moon and wants to send rovers and astronauts there as well - and to eventually build its own lunar base. Ziuyan Ouyang, chief scientist of China's lunarprogramme, talks about the country's ambitious Moon plans.

  1. Moon: Old and New

    NASA Technical Reports Server (NTRS)

    1970-01-01

    This video presents the moon as studied by man for more than 20 centuries. It reviews the history of lunar studies before the first moon landing, the major things learned since Apollo 11, and closes with a resume of lunar investigations scientists would like to undertake in the future.

  2. Apollo 11 Moon Landing

    NASA Technical Reports Server (NTRS)

    1969-01-01

    The crowning achievement for the Saturn V rocket came when it launched Apollo 11 astronauts, Neil Armstrong, Edwin (Buzz) Aldrin, and Michael Collins, to the Moon in July 1969. In this photograph, astronaut Aldrin takes his first step onto the surface of the Moon.

  3. Photograph of surface of moon showing Sinus Medii near center of the moon

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Ellipse II-P-8, located in Sinus Medii near the center of the moon. The center coordinates for the ellipse are 0 degrees 25 minutes north longitude and 1 degree 20 minutes west latitude. It was the eighth primary site photographed by Lunar Orbiter II. Surveyor VI landed approximately five kilometers to the northwest from the center of the ellipse.

  4. Ion processing of ices and the origin of SO2 and O3 on the icy surfaces of the icy jovian satellites

    NASA Astrophysics Data System (ADS)

    Boduch, P.; Brunetto, R.; Ding, J. J.; Domaracka, A.; Kaňuchová, Z.; Palumbo, M. E.; Rothard, H.; Strazzulla, G.

    2016-10-01

    We present new experimental results relative to 144 keV S9+ or Ar9+ ion implantation in targets made of oxygen rich frozen gases (O2, CO2) and mixtures with water ice. Spectra in the UV (200-400 nm) range have been obtained before and after implantation. The targets have been selected because they can be representative of the parent molecules from which SO2 and O3, observed to be present on the surfaces of Jupiter's icy Moons, could be formed due to radiolysis induced by the abundant magnetospheric ions. The results indicate that sulfur dioxide is not detectable after sulfur implantation in oxygen bearing species. Ozone is formed after argon and sulfur ion implantation. Sulfur implantation in O2 and CO2 targets also induces the formation of a band centered at about 255 nm (that we tentatively attribute to SO3- radicals). In the mixtures with water the band appears initially at the same wavelength and shifts to about 247 nm at higher ion fluences possibly indicating the formation of sulfite (HSO3-) ions. An absorption band observed on Ganymede is well fitted by using three components: ozone, sulfite ions and a not identified component having an absorption band centered at 298 nm. In all of the studied cases ion implantation produces a spectral reddening over the investigated spectral range (200-400 nm) that well mimics the observed spectral slopes of Jupiter's icy satellites.

  5. Towards A Moon Village: Vision and Opportunities

    NASA Astrophysics Data System (ADS)

    Foing, Bernard

    2016-04-01

    . Building on previous studies (EuroMoon, lunar polar lander) ESA should develop a mid-class lunar lander (affordable in cost 300 Meu class), demonstrating the expertise at system level for a platform, that could carry innovative competitive robotic payload contributed and already with advance development from member states and international or commercial partners. With teleoperations from Earth and cis-lunar orbit, this will advance progress towards the next steps of Moon Village and beyond. Recommendations: The participants encourage the design and operations of a Moon base simulation at EAC with facility and activities in the context of SpaceShip EAC, with the support of EAC, DLR, ESTEC, ISU and other partners, and collaborations with other Lunar Research Parks worldwide. It was also proposed to have an "ESTEC Moon Village pilot project" where 20 young professional in-terns could be hosted to work concurrently on various aspects (technology, science, instruments platforms, Moon base design, human factors, programmatics, outreach, community events) with links and support activities from ESTEC senior experts, and interactions with colleagues in member states, academia and industries . The workshop finalized with some hands-on experiments, organized with some students demonstrating their work on a lunar lander with tele-operated instruments and systems, and on the measuring spectra of Moon-Mars analogue minerals. The day ended with a refreshing lunar music session, and a networking event on ESTEC ESCAPE where the last informal conversations marked a great wrap up of such exciting day. Follow up Moon Village events are planned in 2016 at ESTEC, EAC and at international community venues. New means of outreach, communications and social media must be developed. You can follow Moon Village tweets, using #MoonVillage, and contribute to the virtual discussions. ESA is really looking forward to engage all stakeholders into the discussion, no matter of their background, nationality

  6. Automated Spacecraft Conjunction Assessment at Mars and the Moon

    NASA Technical Reports Server (NTRS)

    Berry, David; Guinn, Joseph; Tarzi, Zahi; Demcak, Stuart

    2012-01-01

    Conjunction assessment and collision avoidance are areas of current high interest in space operations. Most current conjunction assessment activity focuses on the Earth orbital environment. Several of the world's space agencies have satellites in orbit at Mars and the Moon, and avoiding collisions there is important too. Smaller number of assets than Earth, and smaller number of organizations involved, but consequences similar to Earth scenarios.This presentation will examine conjunction assessment processes implemented at JPL for spacecraft in orbit at Mars and the Moon.

  7. Compositions of Oceans on Icy Solar System Bodies (Invited)

    NASA Astrophysics Data System (ADS)

    Zolotov, M. Y.

    2010-12-01

    Interior oceans may exist on at least several solar system bodies: Europa, Enceladus, Ganymede, Titan and Triton. Compositions of the oceans could reflect bulk chemistries on the bodies, degree and timing of differendentition, current temperature and pressure conditions, and chemical exchanges between icy shells, liquid layers, and suboceanic solids (rocks, sediments, ices and clathrates). Observational signs are sparse and modeling is the major approach to evaluate oceanic compositions. On Europa, a presence of S(VI) species and CO2 at endogenic surface features [1] suggests sulfates and C species (organic and/or inorganic) in the ocean. The detection of NaCl and Na2CO3/NaHCO3-bearing grains emitted from Enceladus [2] implies the dominance of Na, Cl and carbonate/bicarbonate ions in the past and/or present alkaline fluids in the interior. These observations are consistent with independent models for water-rock interaction [3]. Evaluated low contents of other elements (Mg, Fe, Ca, K, S, P, etc.) in initial oceanic waters [3] are accounted for by low solubilities of minerals deposited from water solutions (serpentine, saponite, magnetite, carbonates, sulfides and phosphates). Oceanic redox states are affected by the composition of accreted ices and rocks, hydrogen production through oxidation of solids (mainly Fe-Ni metal) by water and an efficiency of H2 escape. Formation of a sulfate-bearing ocean (as on Europa) through oxidation of sulfides could have been driven by radiolytically-formed oxidants (H2O2, O2), high-temperature (>500 K) hydrothermal activity and H2 escape. Formation of sulfate facilitates leaching of Mg from minerals leading to the Mg-SO4-Na-Cl ocean. Although some of these factors could have played roles on the Galilean satellites, formation of sulfate-bearing oceans beyond Jupiter is unlikely. Accretion of cometary-type ices on moons allows an existence of water-methanol-ammonia liquids at ~153 K, although ammonia could have been sequestered in

  8. Overview of the Project Prometheus Program

    NASA Technical Reports Server (NTRS)

    Burdick, G. M.

    2003-01-01

    This presentation will give an overview of the Project Prometheus Program (PPP, formerly the Nuclear Systems Initiative, NSI) and the Jupiter Icy Moons Orbiter (JIMO) Project (a component of PPP), a mission to the three icy Galilean moons of Jupiter.

  9. Two Moons and the Pleiades from Mars

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Inverted image of two moons and the Pleiades from Mars

    Taking advantage of extra solar energy collected during the day, NASA's Mars Exploration Rover Spirit recently settled in for an evening of stargazing, photographing the two moons of Mars as they crossed the night sky. In this view, the Pleiades, a star cluster also known as the 'Seven Sisters,' is visible in the lower left corner. The bright star Aldebaran and some of the stars in the constellation Taurus are visible on the right. Spirit acquired this image the evening of martian day, or sol, 590 (Aug. 30, 2005). The image on the right provides an enhanced-contrast view with annotation. Within the enhanced halo of light is an insert of an unsaturated view of Phobos taken a few images later in the same sequence.

    On Mars, Phobos would be easily visible to the naked eye at night, but would be only about one-third as large as the full Moon appears from Earth. Astronauts staring at Phobos from the surface of Mars would notice its oblong, potato-like shape and that it moves quickly against the background stars. Phobos takes only 7 hours, 39 minutes to complete one orbit of Mars. That is so fast, relative to the 24-hour-and-39-minute sol on Mars (the length of time it takes for Mars to complete one rotation), that Phobos rises in the west and sets in the east. Earth's moon, by comparison, rises in the east and sets in the west. The smaller martian moon, Deimos, takes 30 hours, 12 minutes to complete one orbit of Mars. That orbital period is longer than a martian sol, and so Deimos rises, like most solar system moons, in the east and sets in the west.

    Scientists will use images of the two moons to better map their orbital positions, learn more about their composition, and monitor the presence of nighttime clouds or haze. Spirit took the five images that make up this composite with the panoramic camera, using the camera's broadband filter, which

  10. Phase behavior and thermodynamic modeling of ices - implications for the geophysics of icy satellites. (Invited)

    NASA Astrophysics Data System (ADS)

    Choukroun, M.

    2010-12-01

    Ground-based observations and space missions to the outer Solar System (Voyager, Galileo, Cassini-Huygens) have evidenced recent geologic activity on many satellites of the giant planets. The diversity in surface expression of these icy moons’ activity is striking: from a scarred and young surface on Europa,1 with hydrated salts that may originate from a liquid layer buried at depth,2 to the South Polar plumes of Enceladus,3 where water ice particles are expelled along with a myriad of more complex molecules,4 to Titan, largest satellite of Saturn, with a dense atmosphere and a hydrocarbon cycle similar to the hydrological cycle on Earth.5 Large icy moons, i.e. with a radius greater than 500 km, share two particularities: a high content in water (on the order of a 30-70% bulk composition), and an interior segregated between a water-dominated mantle and a silicate-dominated core. The many forms water may have beneath the surface (ice polymorphs, liquid, hydrated compounds) bear a crucial role in the detected or alleged activity, and in the potential for astrobiological relevance. Indeed, any endogenic activity can only be approached through geophysical modelling of the internal structure and the thermal evolution. Current internal structure models for the icy moonse.g.,6 rely mainly on the contribution of each internal layer to the moment of inertia, generating non-unique solutions due to the large variability in density of H2O-bearing phases. Thermal evolution models,e.g.,7 can help constrain further the internal structure and geophysical activity, by starting with a given initial composition and state and investigating the thickening of icy layers through time. However, such models require both observational datasets and a precise description, as a function of pressure, temperature, and composition, of the thermophysical properties of the individual layers. Over the past century, experimental studies have provided a comprehensive view of the phase diagram of

  11. Coupling of the Matched Gravity and Electromagnetic Fields of the Sun with Jupiter and its Moons Together in Nearest Portion of Jupiter's Orbit to the Sun as the Main Cause of the Peak of Approximately 11 Yearly Solar Cycles and Hazards from Solar Storms

    NASA Astrophysics Data System (ADS)

    Gholibeigian, Kazem; Gholibeigian, Hassan

    2016-04-01

    On March 13, 1989 the entire province of Quebec Blackout by solar storm during solar cycle 22. The solar storm of 1859, also known as the Carrington event, was a powerful geomagnetic solar storm during solar cycle 10. The solar storm of 2012 during solar cycle 24 was of similar magnitude, but it passed Earth's orbit without striking the plane. All of these solar storms occurred in the peak of 11 yearly solar cycles. In this way, the White House in its project which is focusing on hazards from solar system, in a new strategy and action plan to increase protection from damaging solar emissions, should focus on coupling of the matched Gravity and Electromagnetic Fields)GEFs) of the Sun with Jupiter and its moons together. On the other hand, in solar system, the Jupiter's gravity has largest effect to the Sun's core and its dislocation, because the gravity force between the Jupiter and the Sun is 11.834 times, In addition overlapping of the solar cycles with the Jupiter's orbit period is 11.856 years. These observable factors lead us to the effect of the Jupiter and Sun gravity fields coupling as the main cause of the approximately 11 years duration for solar cycles. Its peak in each cycle is when the Jupiter is in nearest portion to the Sun in its orbit. In this way, the other planets in their coupling with Sun help to the variations and strengthening solar cycles. [Gholibeigian, 7/24/2015http://adsabs.harvard.edu/abs/2014EGU]. In other words, the both matched GEFs are generating by the large scale forced convection system inside the stars and planets [Gholibeigian et. al, AGU Fall Meeting 2015]. These two fields are couple and strengthening each other. The Jupiter with its 67 moons generate the largest coupled and matched GEFs in its core and consequently strongest effect on the Sun's core. Generation and coupling of the Jupiter's GEFs with its moons like Europa, Io and Ganymede make this planet of thousands of times brighter and many times bigger than Earth as the

  12. Examples of the nonlinear dynamics of ballistic capture and escape in the earth-moon system

    NASA Technical Reports Server (NTRS)

    Belbruno, Edward A.

    1990-01-01

    An example of a trajectory is given which is initially captured in an elliptic resonant orbit about the earth and then ballistically escapes the earth-moon system. This is demonstrated by a numerical example in three-dimensions using a planetary ephemeris. Another example shows a mechanism of how an elliptic orbit about the earth can increase its energy by performing a complex nonlinear transition to an elliptic orbit of a larger semi-major axis. Capture is also considered. An application of ballistic capture at the moon via an unstable periodic orbit using the four-body sun-earth-moon-S/C interaction is described.

  13. Icy Schwedeneck field may provide reference

    SciTech Connect

    Not Available

    1985-05-01

    Situated in an icy region of the Baltic Sea, Germany's first offshore field may provide the nation with the reference needed to encroach the arctic market. Production began last winter from one platform in the Schwedeneck-See field, located about three miles off the Baltic Coast. Total reserves have been estimated at more than 18 million bbl. Yearly production by the end of 1986 has been estimated at 294,000 bbl. The first two production platforms were installed in late 1983 in water depths ranging from 50 to 80 ft. Because of the ice hazards inherent in the Baltic, the platforms are concrete designed with steel decks.

  14. Division of Icy Bodies into Groups Based on Surface Properties

    NASA Astrophysics Data System (ADS)

    Schaefer, Bradley E.; Rabinowitz, D. L.; Tourtellottte, S. W.

    2008-09-01

    We propose the division of the icy bodies in the outer Solar System into five groups based on their surface properties. This division can be equivalently made by three definitions involving: size/orbit/color; measured surface properties; the physical mechanisms that reprocess the surfaces. Our first group is the Small/Red bodies (including the red Centaurs, Kuiper Belt Objects, and Scattered Disk Objects) which are 1.5 mag. These surfaces all have albedo <16; percent, and have lost their volatile ices by Jeans escape with cosmic rays reddening the remaining ices. Our second group is the Small/Gray bodies (including the gray Centaurs, Scattered Disk Objects, and Trojans) which are <800; km in diameter and with B-R<1.5 mag. These surfaces all have very low albedo (<6; percent) because their surface ices have been lost due to heating by the Sun at some time in their past orbital history leaving only their original rocky material to cover the surface. Our third group is the Intermediate bodies (Quaoar, Orcus, and Charon) with diameters 800-1400 km. Their surfaces have lost some of the volatile ices (methane and nitrogen in particular) to Jeans escape, while the remaining ices contain ammonia and crystalline water ice with some cryovolcanism. Our fourth group is the Large bodies (Pluto, Eris, Sedna, Triton, and 2005 FY9) with diameters >1400; km. These bodies are large enough to support active cryovolcanism plus seasonal frost formation/sublimation and are large enough so that the methane and nitrogen ices dominate because they have not been lost to Jeans escape. Our fifth group is the Collisional bodies (including the 2003 EL61 collisional family) which all have similar orbits. Their surfaces all have very neutral colors, low opposition surges, and relatively high albedos, because the volatile ices were all lost during the collision leaving a young surface with only water ice.

  15. Lunar orbiting prospector

    NASA Technical Reports Server (NTRS)

    1988-01-01

    One of the prime reasons for establishing a manned lunar presence is the possibility of using the potential lunar resources. The Lunar Orbital Prospector (LOP) is a lunar orbiting platform whose mission is to prospect and explore the Moon from orbit in support of early lunar colonization and exploitation efforts. The LOP mission is divided into three primary phases: transport from Earth to low lunar orbit (LLO), operation in lunar orbit, and platform servicing in lunar orbit. The platform alters its orbit to obtain the desired surface viewing, and the orbit can be changed periodically as needed. After completion of the inital remote sensing mission, more ambitious and/or complicated prospecting and exploration missions can be contemplated. A refueled propulsion module, updated instruments, or additional remote sensing packages can be flown up from the lunar base to the platform.

  16. The Moon Village Concept

    NASA Astrophysics Data System (ADS)

    Messina, Piero; Foing, Bernard H.; Hufenbach, Bernhard; Haignere, Claudie; Schrogl, Kai-Uwe

    2016-07-01

    The "Moon Village" concept Space exploration is anchored in the International Space Station and in the current and future automatic and planetary automatic and robotic missions that pave the way for future long-term exploration objectives. The Moon represents a prime choice for scientific, operational and programmatic reasons and could be the enterprise that federates all interested Nations. On these considerations ESA is currently elaborating the concept of a Moon Village as an ensemble where multiple users can carry out multiple activities. The Moon Village has the ambition to serve a number of objectives that have proven to be of interest (including astronomy, fundamental research, resources management, moon science, etc. ) to the space community and should be the catalyst of new alliances between public and private entities including non-space industries. Additionally the Moon Village should provide a strong inspirational and education tool for the younger generations . The Moon Village will rely both on automatic, robotic and human-tendered structures to achieve sustainable moon surface operations serving multiple purposes on an open-architecture basis. This Europe-inspired initiative should rally all communities (across scientific disciplines, nations, industries) and make it to the top of the political agendas as a the scientific and technological undertaking but also political and inspirational endeavour of the XXI century. The current reflections are of course based on the current activities and plans on board the ISS and the discussion held in international fora such as the ISECG. The paper will present the status of these reflections, also in view of the ESA Council at Ministerial Level 2016, and will give an overview of the on-going activities being carried out to enable the vision of a Moon Village.

  17. Survivability of bacteria ejected from icy surfaces after hypervelocity impact.

    PubMed

    Burchell, Mark J; Galloway, James A; Bunch, Alan W; Brandão, Pedro F B

    2003-02-01

    Both the Saturnian and Jovian systems contain satellites with icy surfaces. If life exists on any of these icy bodies (in putative subsurface oceans for example) then the possibility exists for transfer of life from icy body to icy body. This is an application of the idea of Panspermia, wherein life migrates naturally through space. A possible mechanism would be that life, here taken as bacteria, could become frozen in the icy surface of one body. If a high-speed impact occurred on that surface, ejecta containing the bacteria could be thrown into space. It could then migrate around the local region of space until it arrived at a second icy body in another high-speed impact. In this paper we consider some of the necessary steps for such a process to occur, concentrating on the ejection of ice bearing bacteria in the initial impact, and on what happens when bacteria laden projectiles hit an icy surface. Laboratory experiments using high-speed impacts with a light gas gun show that obtaining icy ejecta with viable bacterial loads is straightforward. In addition to demonstrating the viability of the bacteria carried on the ejecta, we have also measured the angular and size distribution of the ejecta produced in hypervelocity impacts on ice. We have however been unsuccessful at transferring viable bacteria to icy surfaces from bacteria laden projectiles impacting at hypervelocities. PMID:12967273

  18. Origin of earth's moon

    NASA Technical Reports Server (NTRS)

    Wood, J. A.

    1977-01-01

    The major geochemical properties of the moon are briefly considered along with the significant facts of the moon's geologic history, and then the three current hypotheses regarding the moon's origin, namely, fission, capture, and binary accretion, are reviewed. The individual merits and improbabilities associated with each mechanism are taken into consideration. Special attention is given to the binary accretion model as the most promising one. In the variants of this model, of crucial importance is the nature of the more general hypothesis assumed for planetary formation from the solar nebula. The two main models differ considerably in the amount of chemical fractionation they allow to accompany planetary formation.

  19. Why the Moon?

    NASA Technical Reports Server (NTRS)

    Gaier, James R.

    2009-01-01

    In 2004, President George W. Bush proposed a new set of goals for NASA which have since been formalized by Congress as the revised United States Space Policy. A major goal is to return humans to the moon by 2020. This prompted a world-wide discussion about what our goals in space ought to be. In 2006 NASA surveyed potential stakeholders asking the question, "Why the Moon?" Responses were received from over 1000 entities including business, industry, academia, and 13 other space agencies. This presentation reports the responses to that questionnaire, as well as current plans for how the return to the moon will be accomplished.

  20. Realistic ice sputtering experiments for the surfaces of Galilean moons

    NASA Astrophysics Data System (ADS)

    Galli, A.; Pommerol, A.; Wurz, P.; Jost, B.; Scheer, J. A.; Vorburger, A.; Tulej, M.; Thomas, N.; Wieser, M.; Barabash, S.

    2015-10-01

    We use an existing laboratory facility for space hardware calibration in vacuum to study the impact of energetic ions on water ice. The experiment is intended to simulate the conditions on the surface of Jupiter's icy moons. The first results of hydrogen, oxygen, and sulphur ions sputtering a sample of porous salty ice confirmed extrapolations from previous sputtering experiments obtained at different impact angles for nonporous water ice [3]. Here, we present additional measurements for a larger range of ion impact angles and different ice samples.

  1. Flow and fracture of ices, with application to icy satellites (Invited)

    NASA Astrophysics Data System (ADS)

    Durham, W. B.; Stern, L. A.; Pathare, A.; Golding, N.

    2013-12-01

    large icy moons; flow of very low melting temperature, weakly bonded solids such as N2, CH4, and CO2; and the behavior of ice-rich, large exoplanets. We will review recent results on the rheological behavior of water ice I in the regime of combined flow by grain size sensitive and grain size insensitive mechanisms of deformation, and in particular the possibility that grain size is not a free variable when ice I deforms over large strains for long periods of time, but rather is defined by stress and temperature. Existing rheological laws suggest that viscosity of an ice-I-rich outer layer on a large icy moon, including a moon as small as Enceladus, may be strongly grain size dependent. We will also review developments in two-phase flow, with implications for geysers on Enceladus and methane in Titan's atmosphere.

  2. Looking for planetary moons in the spectra of distant Jupiters.

    PubMed

    Williams, D M; Knacke, R F

    2004-01-01

    More than 100 nearby stars are known to have at least one Jupiter-sized planet. Whether any of these giant gaseous planets has moons is unknown, but here we suggest a possible way of detecting Earth-sized moons with future technology. The planned Terrestrial Planet Finder observatory, for example, will be able to detect objects comparable in size to Earth. Such Earth-sized objects might orbit their stars either as isolated planets or as moons to giant planets. Moons of Jovian-sized planets near the habitable zones of main-sequence stars should be noticeably brighter than their host planets in the near-infrared (1-4 microm) if their atmospheres contain methane, water, and water vapor, because of efficient absorption of starlight by these atmospheric components. By taking advantage of this spectral contrast, future space observatories will be able to discern which extrasolar giant planets have Earth-like moons capable of supporting life. PMID:15383243

  3. ISA accelerometer and Moon science

    NASA Astrophysics Data System (ADS)

    Iafolla, Valerio; Peron, Roberto; Santoli, Francesco; Fiorenza, Emiliano; Lefevre, Carlo; Nozzoli, Sergio; Reale, Andrea

    2010-05-01

    In recent years the Moon has become again a target for exploration activities, as shown by many performed, ongoing or foreseen missions. The reason for this new wave are manifold. The knowledge of formation and evolution of the Moon to current state is important in order to trace the overall history of Solar System. An effective driving factor is the possibility of building a human settlement on its surface, with all the related issues of environment characterization, safety, resources, communication and navigation. Our natural satellite is also an important laboratory for fundamental physics: Lunar Laser Ranging is continuing to provide important data that constrain possible theories of gravitation. All these topics are providing stimulus and inspirations for new experiments. ISA (Italian Spring Accelerometer) can provide an important tool for lunar studies. Thanks to its structure (three one-dimensional sensors assembled in a composite structure) it works both in-orbit and on-ground, with the same configuration. It therefore can be used onboard a spacecraft, as a support to a radio science mission, and on the surface of the Moon, as a seismometer. The first option has been explorated in the context of MAGIA (Missione Altimetrica Gravimetrica geochImica lunAre), a proposal for an exploration mission with a noteworthy part dedicated to gravimetry and fundamental physics. The second option is candidate to be hosted on NASA ILN (International Lunar Network) and ESA First Lunar Lander. After a description of the instrument, both of them will be described and discussed, giving emphasis on the integration of the instrument with the other components of the respective experiments.

  4. Porosity and the ecology of icy satellites

    NASA Technical Reports Server (NTRS)

    Croft, Steven K.

    1993-01-01

    The case for a significant role for porosity in the structure and evolution of icy bodies in the Solar System has been difficult to establish. We present a relevant new data set and a series of structure models including a mechanical compression, not thermal creep, model for porosity that accounts satisfactorily for observed densities, moments of inertia, geologic activity, and sizes of tectonic features on icy satellites. Several types of observational data sets have been used to infer significant porosity, but until recently, alternative explanations have been preferred. Our first area of concern is the occurrence of cryovolcanism as a function of satellite radius; simple radiogenic heating models of icy satellites suggest minimum radii for melting and surface cryovolcanism to be 400 to 500 km, yet inferred melt deposits are seen on satellites half that size. One possible explanation is a deep, low conductivity regolith which lowers conductivity and raises internal temperatures, but other possibilities include tidal heating or crustal compositions of low conductivity. Our second area of concern is the occurrence and magnitude of tectonic strain; tectonic structures have been seen on icy satellites as small as Mimas and Proteus. The structures are almost exclusively extensional, with only a few possible compression Al features, and inferred global strains are on the order of 1 percent expansion. Expansions of this order in small bodies like Mimas and prevention of late compressional tectonics due to formation of ice mantles in larger bodies like Rhea are attained only in structure models including low-conductivity, and thus possibly high porosity, crusts. Thirdly, inferred moments of inertia less than 0.4 in Mimas and Tethys can be explained by high-porosity crusts, but also by differentiation of a high density core. Finally, the relatively low densities of smaller satellites like Mimas and Miranda relative to larger neighbors can be explained by deep porosity

  5. Launching to the Moon, Mars, and Beyond

    NASA Technical Reports Server (NTRS)

    Shivers, C. Herbert

    2008-01-01

    This viewgraph presentation reviews the planned launching to the Moon, and Mars. It is important to build beyond the capacity to ferry astronauts and cargo to low Earth orbit. NASA is starting to design new vehicles using the past lessons to minimize cost, and technical risks. The training and education of engineers that will continue the work of designing, testing and flying the vehicles is important to NASA.

  6. Return to the Moon: Lunar robotic science missions

    NASA Technical Reports Server (NTRS)

    Taylor, Lawrence A.

    1992-01-01

    There are two important aspects of the Moon and its materials which must be addressed in preparation for a manned return to the Moon and establishment of a lunar base. These involve its geologic science and resource utilization. Knowledge of the Moon forms the basis for interpretations of the planetary science of the terrestrial planets and their satellites; and there are numerous exciting explorations into the geologic science of the Moon to be conducted using orbiter and lander missions. In addition, the rocks and minerals and soils of the Moon will be the basic raw materials for a lunar outpost; and the In-Situ Resource Utilization (ISRU) of lunar materials must be considered in detail before any manned return to the Moon. Both of these fields -- planetary science and resource assessment -- will necessitate the collection of considerable amounts of new data, only obtainable from lunar-orbit remote sensing and robotic landers. For over fifteen years, there have been a considerable number of workshops, meetings, etc. with their subsequent 'white papers' which have detailed plans for a return to the Moon. The Lunar Observer mission, although grandiose, seems to have been too expensive for the austere budgets of the last several years. However, the tens of thousands of man-hours that have gone into 'brainstorming' and production of plans and reports have provided the precursor material for today's missions. It has been only since last year (1991) that realistic optimism for lunar orbiters and soft landers has come forth. Plans are for 1995 and 1996 'Early Robotic Missions' to the Moon, with the collection of data necessary for answering several of the major problems in lunar science, as well as for resource and site evaluation, in preparation for soft landers and a manned-presence on the Moon.

  7. System description and operating guide for DSAS illumination and moon conflict programs

    NASA Technical Reports Server (NTRS)

    Dunker, S. C.

    1973-01-01

    The DSAS Illumination and Moon Conflict programs are described which during an orbit when the DSAS (Digital Solar Aspect Sensor) will record the direct rays of the sun, and the periods of time when the horizon scanners will come in conflict with the moon. The DSAS Illumination Program makes use of an orbit tape (or epoch time and orbital elements) in addition to an ephemeris tape containing positions of the sun and moon. The Moon Conflict Program makes use of the same ephemeris tape with sun and moon positions, but uses only epoch time and orbital elements for the satellite positions. These programs were designed for the TIROS or ITOS series spacecraft but may be utilized by any spacecraft with similar sensors.

  8. What's New on the Moon?

    ERIC Educational Resources Information Center

    French, Bevan M.

    This document presents an overview of knowledge gained from the scientific explorations of the moon between 1969 and 1972 in the Apollo Program. Answers are given to questions regarding life on the moon, surface composition of rocks on the moon, the nature of the moon's interior, characteristics of lunar "soil," the age, history and origin of the…

  9. TRANSIT MODEL OF PLANETS WITH MOON AND RING SYSTEMS

    SciTech Connect

    Tusnski, Luis Ricardo M.; Valio, Adriana E-mail: avalio@craam.mackenzie.br

    2011-12-10

    Since the discovery of the first exoplanets, those most adequate for life to begin and evolve have been sought. Due to observational bias, however, most of the discovered planets so far are gas giants, precluding their habitability. However, if these hot Jupiters are located in the habitable zones of their host stars, and if rocky moons orbit them, then these moons may be habitable. In this work, we present a model for planetary transit simulation considering the presence of moons and planetary rings around a planet. The moon's orbit is considered to be circular and coplanar with the planetary orbit. The other physical and orbital parameters of the star, planet, moon, and rings can be adjusted in each simulation. It is possible to simulate as many successive transits as desired. Since the presence of spots on the surface of the star may produce a signal similar to that of the presence of a moon, our model also allows for the inclusion of starspots. The result of the simulation is a light curve with a planetary transit. White noise may also be added to the light curves to produce curves similar to those obtained by the CoRoT and Kepler space telescopes. The goal is to determine the criteria for detectability of moons and/or ring systems using photometry. The results show that it is possible to detect moons with radii as little as 1.3 R{sub Circled-Plus} with CoRoT and 0.3 R{sub Circled-Plus} with Kepler.

  10. The Moon: Biogenic elements

    NASA Technical Reports Server (NTRS)

    Gibson, Everett K., Jr.; Chang, Sherwood

    1992-01-01

    The specific objectives of the organic chemical exploration of the Moon involve the search for molecules of possible biological or prebiological origin. Detailed knowledge of the amount, distribution, and exact structure of organic compounds present on the Moon is extremely important to our understanding of the origin and history of the Moon and to its relationship to the history of the Earth and solar system. Specifically, such knowledge is essential for determining whether life on the Moon exists, ever did exist, or could develop. In the absence of life or organic matter, it is still essential to determine the abundance, distribution, and origin of the biogenic elements (e.g., H, C, O, N, S, P) in order to understand how the planetary environment may have influenced the course of chemical evolution. The history and scope of this effort is presented.

  11. Full Moon Feeling

    NASA Astrophysics Data System (ADS)

    Ortiz-Gil, A.; Ballesteros Roselló, F.; Fernández-Soto, A.; Lanzara, M.; Moya, M. J.

    2012-09-01

    The Moon is, together with the Sun, the very first astronomical object that we experience in our life. As this is an exclusively visual experience, people with visual impairments need to follow a different path to experience it too. Here we will show the process of designing and testing a tactile 3D Moon sphere whose goal is to reproduce on a tactile support the experience of observing the Moon visually. We have used imaging data obtained by NASA's mission Clementine, along with free image processing and 3D rendering software. This method is also useful to produce other artifacts that can be employed in the communication of astronomy to all kinds of public. The tactile Moon project for the blind has been funded partially by the 2011 Europlanet Outreach Funding Scheme.

  12. Geometry and Moon Phases.

    ERIC Educational Resources Information Center

    Thompson, Kenneth W.; Harrell, Marvin E.

    1997-01-01

    Describes an activity, designed to comply with the National Science Education Standards, that integrates science and mathematics concepts. Mathematical modeling of the moon's phases is employed to show students the role of mathematics in describing scientific phenomena. (DKM)

  13. Cassini's Grand Finale: The Final Orbits

    NASA Astrophysics Data System (ADS)

    Spilker, Linda; Edgington, Scott

    2016-04-01

    The Cassini-Huygens mission, a joint collaboration between NASA, ESA and the Italian Space Agency, is approaching its last year of operations after nearly 12 years in orbit around Saturn. Cassini will send back its final bits of unique data on September 15th, 2017 as it plunges into Saturn's atmosphere, vaporizing and satisfying planetary protection requirements. Before that time Cassini will continue its legacy of exploration and discovery with 12 close flybys of Titan in 2016 and 2017 that will return new science data as well as sculpt the inclinations and periods of the final orbits. Even though all of our close icy satellite flybys, including those of Enceladus, are now completed, numerous Voyager-class flybys (<100,000 km) of Mimas and Enceladus remain as well as some of our best flybys of the tiny ring moons. Cassini will also continue to study seasonal and temporal changes in the system as northern summer solstice approaches. In November 2016 Cassini will transition to a series of orbits with peripases just outside Saturn's F ring. These 20 orbits will include close flybys of some tiny ring moons and excellent views of the F ring and outer A ring. The 126th and final close flyby of Titan will propel Cassini across Saturn's main rings and into its final orbits. Cassini's Grand Finale, starting in April 2017, is comprised of 22 orbits at an inclination of 63 degrees. Cassini will repeatedly dive between the innermost rings and the upper atmosphere of the planet providing insights into fundamental questions unattainable during the rest of the mission. Cassini will be the first spacecraft to explore this region. These close orbits provide the highest resolution observations of both the rings and Saturn, and direct in situ sampling of the ring particles, composition, plasma, Saturn's exosphere and the innermost radiation belts. Saturn's gravitational field will be measured to unprecedented accuracy, providing information on the interior structure of the planet

  14. Habitable moons around extrasolar giant planets

    NASA Technical Reports Server (NTRS)

    Williams, D. M.; Kasting, J. F.; Wade, R. A.

    1997-01-01

    Possible planetary objects have now been discovered orbiting nine different main-sequence stars. These companion objects (some of which might actually be brown dwarfs) all have a mass at least half that of Jupiter, and are therefore unlikely to be hospitable to Earth-like life: jovian planets and brown dwarfs support neither a solid nor a liquid surface near which organisms might dwell. Here we argue that rocky moons orbiting these companions could be habitable if the planet-moon system orbits the parent star within the so-called 'habitable zone', where life-supporting liquid water could be present. The companions to the stars 16 Cygni B and 47 Ursae Majoris might satisfy this criterion. Such a moon would, however, need to be large enough (>0.12 Earth masses) to retain a substantial and long-lived atmosphere, and would also need to possess a strong magnetic field in order to prevent its atmosphere from being sputtered away by the constant bombardment of energetic ions from the planet's magnetosphere.

  15. Habitable moons around extrasolar giant planets.

    PubMed

    Williams, D M; Kasting, J F; Wade, R A

    1997-01-16

    Possible planetary objects have now been discovered orbiting nine different main-sequence stars. These companion objects (some of which might actually be brown dwarfs) all have a mass at least half that of Jupiter, and are therefore unlikely to be hospitable to Earth-like life: jovian planets and brown dwarfs support neither a solid nor a liquid surface near which organisms might dwell. Here we argue that rocky moons orbiting these companions could be habitable if the planet-moon system orbits the parent star within the so-called 'habitable zone', where life-supporting liquid water could be present. The companions to the stars 16 Cygni B and 47 Ursae Majoris might satisfy this criterion. Such a moon would, however, need to be large enough (>0.12 Earth masses) to retain a substantial and long-lived atmosphere, and would also need to possess a strong magnetic field in order to prevent its atmosphere from being sputtered away by the constant bombardment of energetic ions from the planet's magnetosphere. PMID:9000072

  16. SUDA: A Dust Mass Spectrometer for compositional surface mapping for the JUICE mission to the Galilean moons

    NASA Astrophysics Data System (ADS)

    Kempf, S.; Briois, C.; Cottin, H.; Engrand, C.; Gruen, E.; Hand, K. P.; Henkel, H.; Horanyi, M.; Lankton, M. R.; Lebreton, J.; Postberg, F.; Schmidt, J.; Srama, R.; Sternovsky, Z.; Thissen, R.; Tobie, G.; Szopa, C.; Zolotov, M. Y.

    2012-12-01

    We developed a dust mass spectrometer to measure the composition of ballistic dust particles populating the thin exospheres that were detected around each of the Galilean moons. Since these grains are direct samples from the moons' icy surfaces, unique composition data will be obtained that will help to define and constrain the geological activities on and below the moons' surface. The proposed instrument will make a vital contribution to ESA's planned JUICE mission and provide key answers to its main scientific questions about the surface composition, habitability, the icy crust, and exchange processes with the deeper interior of the Jovian icy moons Europa, Ganymede, and Callisto. The SUrface Dust Aanalyser (SUDA) is a time-of-flight, reflectron-type impact mass spectrometer, opti-mised for a high mass resolution which only weakly depends on the impact location. The small size (268×250×171 mm3), low mass (< 4 kg) and large sen-sitive area (220 cm2) makes the instrument well suited for the challenging demands of the JUICE mission to the Galilean moons Europa, Ganymede, and Callisto. A full-size prototype SUDA instrument was built in order to demonstrate its performance through calibra-tion experiments at the Heidelberg dust accelerator with a variety of cosmo-chemically relevant dust ana-logues. The effective mass resolution of m/Δm of 150-200 is achieved for mass range of interest m = 1-150.

  17. Approaching Moons from Resonance via Invariant Manifolds

    NASA Technical Reports Server (NTRS)

    Anderson, Rodney L.

    2012-01-01

    In this work, the approach phase from the final resonance of the endgame scenario in a tour design is examined within the context of invariant manifolds. Previous analyses have typically solved this problem either by using numerical techniques or by computing a catalog of suitable trajectories. The invariant manifolds of a selected set of libration orbits and unstable resonant orbits are computed here to serve as guides for desirable approach trajectories. The analysis focuses on designing an approach phase that may be tied into the final resonance in the endgame sequence while also targeting desired conditions at the moon.

  18. Supporting Crewed Missions using LiAISON Navigation in the Earth-Moon System

    NASA Astrophysics Data System (ADS)

    Leonard, Jason M.

    Crewed navigation in certain regions of the Earth-Moon system provides a unique challenge due to the unstable dynamics and observation geometry relative to standard Earth-based tracking systems. The focus of this thesis is to advance the understanding of navigation precision in the Earth-Moon system, analyzing the observability of navigation data types frequently used to navigate spacecraft, and to provide a better understanding of the influence of a crewed vehicle disturbance model for future manned missions in the Earth-Moon system. In this research, a baseline for navigation performance of a spacecraft in a Lagrange point orbit in the Earth-Moon system is analyzed. Using operational ARTEMIS tracking data, an overlap analysis of the reconstructed ARTEMIS trajectory states is conducted. This analysis provides insight into the navigation precision of a spacecraft traversing a Lissajous orbit about the Earth-Moon L1 point. While the ARTEMIS analysis provides insight into the navigation precision using ground based tracking methods, an examination of the benefits of introducing Linked Autonomous Interplanetary Satellite Orbit Navigation (LiAISON) is investigated. This examination provides insight into the benefits and disadvantages of LiAISON range and range-rate measurements for trajectories in the Earth-Moon system. In addition to the characterization of navigation precision for spacecraft in the Earth-Moon system, an analysis of the uncertainty propagation for noisy crewed vehicles and quiet robotic spacecraft is given. Insight is provided on the characteristics of uncertainty propagation and how it is correlated to the instability of the Lagrange point orbit. A crewed vehicle disturbance model is provided based on either Gaussian or Poisson assumptions. The natural tendency for the uncertainty distribution in a Lagrange point orbit is to align with the unstable manifold after a certain period of propagation. This behavior is influenced directly by the unstable

  19. Cassini UVIS Results from Occultations of Stars by Saturn's Icy Moons

    NASA Astrophysics Data System (ADS)

    Hansen, Candice; Hendrix, A.

    2009-09-01

    The Cassini Ultraviolet Imaging Spectrograph (UVIS) has observed occultations of stars by Enceladus, Tethys, Dione, Rhea and Iapetus. Stellar occultations are a sensitive probe for gases and have been extremely valuable for understanding the composition (predominantly water), flux and structure of Enceladus’ plume [1, 2]. More recently we have been looking for trace gases in the plume such as ethylene and methanol. A much-anticipated solar occultation will be observed next year to quantify the existence and amount of N2. At Tethys and Iapetus upper limits are set for the column densities of local volatiles (water, O2, CO2, and CO), all of which have absorption features at far ultraviolet wavelengths. The Rhea occultation data, in addition to setting upper limits on surrounding gases, have been analyzed to look for the presence of the debris disk reported by Cassini's MIMI instrument [3]. No material was detected with 2 sigma certainty, however the low optical depth of the material suggests that the probability of its detection by UVIS is < 1 in 1000. An occultation of epsilon Canis Majoris by Dione will take place in September 2009. Results of that occultation will be presented. This work was partially supported by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. [1] Hansen, C. J. et al., Science 311:1422 (2006). [2] Hansen, C. J. et al., Nature 456 (2008). [3] Jones, G. H. et al., Science 319:1380 (2008).

  20. High-powered Radar Sounders for the Investigation of Jupiter's Icy Moons

    NASA Technical Reports Server (NTRS)

    Safaeinili, A.; Rodriguez, E.; Edelstein, Wendy

    2003-01-01

    This talk will address the main drivers in the design of a radar sounder for the JIMO mission and provide a potential solution that will optimize the chances of success in the detection of ice/water interface and sub-surface stratigraphy.

  1. An Open-Source GUI for Calculating Icy Moon Tidal Stresses Using SatStress

    NASA Astrophysics Data System (ADS)

    Kay, J. P.; Kattenhorn, S. A.

    2010-03-01

    We have used the open-source program SatStress to develop a graphic user interface (GUI) for calculating tidal stresses on the surface of a satellite with both elastic and viscoelastic rheology. SatStress GUI will eventually be open-source.

  2. Two Moons and the Pleiades from Mars

    NASA Technical Reports Server (NTRS)

    2005-01-01

    the surface of Mars would notice its oblong, potato-like shape and that it moves quickly against the background stars. Phobos takes only 7 hours, 39 minutes to complete one orbit of Mars. That is so fast, relative to the 24-hour-and-39-minute sol on Mars (the length of time it takes for Mars to complete one rotation), that Phobos rises in the west and sets in the east. Earth's moon, by comparison, rises in the east and sets in the west. The smaller martian moon, Deimos, takes 30 hours, 12 minutes to complete one orbit of Mars. That orbital period is longer than a martian sol, and so Deimos rises, like most solar system moons, in the east and sets in the west.

    Scientists will use images of the two moons to better map their orbital positions, learn more about their composition, and monitor the presence of nighttime clouds or haze. Spirit took the five images that make up this composite with the panoramic camera, using the camera's broadband filter, which was designed specifically for acquiring images under low-light conditions.

  3. Radiation Induced Chemistry of Icy Surfaces: Laboratory Simulations

    NASA Technical Reports Server (NTRS)

    Gudipati, Murthy S.; Lignell, Antti; Li, Irene; Yang, Rui; Jacovi, Ronen

    2011-01-01

    We will discuss laboratory experiments designed to enhance our understanding the chemical processes on icy solar system bodies, enable interpretation of in-situ and remote-sensing data, and help future missions to icy solar system bodies, such as comets, Europa, Ganymede, Enceladus etc.

  4. Hybrid simulations of moon-magnetosphere interactions at Saturn (Invited)

    NASA Astrophysics Data System (ADS)

    Kriegel, H.

    2010-12-01

    Saturn's moons offer a huge variety of different types of plasma interactions of the planet's dipole field and magnetospheric plasma with the moon's solid body, its atmosphere in the case of Titan or plume in the case of Enceladus. These objects are embedded in rather different environments resulting e.g. in subalfvenic or superalfvenic interaction types with very different spatial and temporal scales. To all these diverse scenarios we successfully apply our hybrid simulation code A.I.K.E.F. (adaptive ion kinetic electron fluid) and investigate the underlying physical processes: The icy satellites Tethys and Rhea do not possess a significant atmosphere, leading to a direct absorption of the impinging magnetospheric plasma at the moons' surfaces. We analyze how the density void is refilled by counter-streaming ions as well as the weak magnetic perturbations measured by Cassini in the moons’ wakes. At Titan, the ion gyroradii are comparable to the radius of the moon, requiring a kinetic description of the asymmetric pick-up tail. We present real-time simulations of Titan's plasma interaction in a dynamical environment like the magnetopause crossing that was observed during Cassini's T32 flyby. The different field and plasma flow orientations in magnetosphere and -sheath result in fossil fields in Titan's lower ionosphere as well as in a large-scale reconfiguration of the pick-up tail, which can only be resolved simultaneously by using an adaptive mesh. Enceladus represents a unique combination of both, the icy-satellite-type-interaction and the interaction with a spatially displaced dense atmosphere, i.e. its plume. Our model is the first one to connect a realistic model of the multiple jets forming the neutral plume with a self-consistent description of the momentum loading process due to charge exchange. By comparing our latest simulation results with Cassini magnetometer data (MAG), we investigate the highly twisted structure of the Alfven wing system triggered

  5. Galilean Moons, Kepler's Third Law, and the Mass of Jupiter

    NASA Astrophysics Data System (ADS)

    Bates, Alan

    2013-10-01

    Simulations of physical systems are widely available online, with no cost, and are ready to be used in our classrooms. ,2 Such simulations offer an accessible tool that can be used for a range of interactive learning activities. The Jovian Moons Applet2 allows the user to track the position of Jupiter's four Galilean moons with a variety of viewing options. For this activity, data are obtained from the orbital period and orbital radii charts. Earlier experiments have used telescopes to capture the orbital motion of the Galilean moons,3 although observation of astronomical events and the measurement of quantities may be difficult to achieve due to a combination of cost, training, and observing conditions. The applet allows a suitable set of data to be generated and data analysis that verifies Kepler's third law of planetary motion, which leads to a calculated value for the mass of Jupiter.

  6. Properties of the solar nebula and the origin of the moon.

    NASA Technical Reports Server (NTRS)

    Cameron, A. G. W.

    1973-01-01

    The basic geochemical model of the structure of the moon proposed by Anderson, in which the moon is formed by differentiation of the calcium, aluminium, and titanium-rich inclusions in the Allende meteorite, is accepted, and the conditions for formation of this moon within the solar nebula models of Cameron and Pine are discussed. The basic material condenses while iron remains in the gaseous phase, which places the formation of the moon slightly inside the orbit of Mercury. Some condensed metallic iron is likely to enter the moon in this position, and since the moon is assembled at a very high temperature, it is likely to have been fully molten, so that the iron can remove the iridium from the silicate material and carry it down to form a small core. Interactions between the moon and Mercury lead to the present rather eccentric Mercury orbit and to a much more eccentric orbit for the moon, reaching past the orbit of the earth, establishing conditions which are necessary for capture of the moon by the earth.

  7. Saturn's icy satellites - Thermal and structural models

    NASA Technical Reports Server (NTRS)

    Ellsworth, K.; Schubert, G.

    1983-01-01

    Thermal history models which assume formation as homogeneous ice-silicate mixtures are constructed for the small, icy Saturnian satellites Mimas, Tethys, Dione, Rhea, and Iapetus, including the effects of radiogenic and accretional heating, conductive and subsolidus convective heat transfer, and lithosphgeric growth. Accretional heating is not likely to have melted the water ice in the interiors of these bodies, and solid state creep of the ice-dominated material precludes melting by radiogenic heating. The four largest satellites are sufficiently large and rich in heat-producing silicates to possess a solid state convection system beneath a rigid lithosphere, irrespective of initial conditions. The model thermal histories are qualitatively consistent with the present appearances of these satellites.

  8. Processing of icy mantles in protostellar envelopes

    NASA Technical Reports Server (NTRS)

    Chiar, J. E.; Gerakines, P. A.; Whittet, D. C.; Pendleton, Y. J.; Tielens, A. G.; Adamson, A. J.; Boogert, A. C.

    1998-01-01

    We have obtained CO absorption profiles of several young stellar objects (YSOs), spanning a range of mass and luminosity, in order to investigate their ice mantle composition. We present the first detection of CO toward the class I YSO L1489 IRS in the Taurus dark cloud. In general, the CO profiles for YSOs show evidence for both processed and pristine ices in the same line of sight, strong indirect evidence for CO, is suggested in R CrA IRS 7, L1489 IRS, Elias 18, and GL 961E. Toward other sources (R CrA IRS 1, IRS 2, W33A, NGC 7538 IRS 9, Mon R2 IRS 2) CO is present in (nearly) pure form. We propose an evolutionary scenario to explain the chemical diversity of the icy mantles toward these objects.

  9. Internal translational dynamics of large icy bodies

    NASA Astrophysics Data System (ADS)

    Escapa, A.

    2012-09-01

    Rotational dynamics is broadly used as a way to obtain some insight into the interior of solar system celestial bodies (e.g., see [4]). This is due to the fact that, to some extent, the rotational motion is affected by the internal characteristics of the body like its stratification, rheological properties, etc. Running a parallel way, some interior models of the celestial bodies also lead to the existence of another different rigid motion related with the translations of the body constituents with respect to its barycenter. It is the case, for example, of differentiated bodies containing a fluid layer enclosed between two solid layers. These kind of motions, like the rotational ones, might provide some constrains on the physical properties of the body, hence the interest in their study. This question has been recently addressed in [1] within the context of icy bodies. In that work it was established a mathematical framework, based on Lagrangian mechanics methods, that allowed the analytical modeling of the internal translational motions of a simple body differentiated into three homogeneous layers: an external ice-I layer, a subsurface ammonia-water ocean, and a rocky inner core. It was shown that the nature of the motion is oscillatory, with a single frequency, analogous to the Earth Slichter mode, that depends on the densities and masses of the layers. Although this three-layer internal structure represents a good approximation for some possible models of the interior of medium-sized icy bodies containing a subsurface ocean (e.g., see [2]), it is not the case when considering other models of larger icy bodies like Ganymede or Titan, since for them the subsurface ocean is not in contact with the rocky inner core but with a high-pressure ice layer (e.g., see [3], [5] or [6]). Bearing in mind these considerations, we aim at modeling the internal translational motions of a body composed of an ice crust, a subsurface ocean, and an inner core differentiated in two

  10. Low Force Penetration of Icy Regolith

    NASA Technical Reports Server (NTRS)

    Mantovani, J. G.; Galloway, G. M.; Zacny, K.

    2016-01-01

    A percussive cone penetrometer measures the strength of granular material by using percussion to deliver mechanical energy into the material. A percussive cone penetrometer was used in this study to penetrate a regolith ice mixture by breaking up ice and decompacting the regolith. As compared to a static cone penetrometer, percussion allows low reaction forces to push a penetrometer probe tip more easily into dry regolith in a low gravity environment from a planetary surface rover or a landed spacecraft. A percussive cone penetrates icy regolith at ice concentrations that a static cone cannot penetrate. In this study, the percussive penetrator was able to penetrate material under 65 N of down-force which could not be penetrated using a static cone under full body weight. This paper discusses using a percussive cone penetrometer to discern changes in the concentration of water-ice in a mixture of lunar regolith simulant and ice to a depth of one meter. The rate of penetration was found to be a function of the ice content and was not significantly affected by the down-force. The test results demonstrate that this method may be ideal for a small platform in a reduced gravity environment. However, there are some cases where the system may not be able to penetrate the icy regolith, and there is some risk of the probe tip becoming stuck so that it cannot be retracted. It is also shown that a percussive cone penetrometer could be used to prospect for water ice in regolith at concentrations as high as 8 by weight.

  11. Lageos orbit and solar eclipses

    NASA Technical Reports Server (NTRS)

    Rubincam, D. P.

    1984-01-01

    The objective was to assess the importance of solar eclipses on Lageos' orbit. Solar radiation pressure perturbs the orbit of the Lageos satellite. The GEODYN orbit determination computer program includes solar radiation pressure as one of the forces operating on the satellite as it integrates the orbit. GEODYN also takes into account the extinction of sunlight when Lageos moves into the Earth's shadow. The effect of solar eclipses on the semimajor axis of Lageos' orbit was computed analytically by assuming Lageos to be in a circular orbit, the Sun and the Moon to be in the plane of the orbit, and the Moon to be stationary in the sky in front of the Sun. Also, the magnitude of the radiation pressure is assumed to be linearly related to the angular separation of the Sun and Moon, and that Lageos is a perfect absorber of radiation. The computation indicates that an eclipse of the Sun by the Moon as seen by Lageos can affect the semimajor axis at the 1 centimeter (1 cm) level. Such a change is significant enough to include in GEODYN, in order to get an accurate orbit for Lageos.

  12. Semi-brittle behavior of a multi-phase crust and its influence on the tectonics of icy satellites

    NASA Astrophysics Data System (ADS)

    McCarthy, Christine; Cooper, Reid F.

    2010-05-01

    -ductile transition by 55% and reduce the strength in both the plastic and the brittle regimes, thereby blunting the ends of a lithospheric strength envelope, effectively reducing the failure limit for contractional surface features from 10MPa to ~6MPa. Our study thus provides a potential explanation for zones of weakness, such as folds and buckling, observed in the crusts of icy satellites. We have derived a constitutive equation for the eutectic aggregates that includes eutectic-colony boundary sliding, intracolony flow and cavitation. The stress-strain relationships we have obtained will improve our understanding of tectonics and surface features on icy moons of the outer solar system.

  13. Moon - False Color Mosaic

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This false-color photograph is a composite of 15 images of the Moon taken through three color filters by Galileo's solid-state imaging system during the spacecraft's passage through the Earth-Moon system on December 8, 1992. When this view was obtained, the spacecraft was 425,000 kilometers (262,000 miles) from the Moon and 69,000 kilometers (43,000 miles) from Earth. The false-color processing used to create this lunar image is helpful for interpreting the surface soil composition. Areas appearing red generally correspond to the lunar highlands, while blue to orange shades indicate the ancient volcanic lava flow of a mare, or lunar sea. Bluer mare areas contain more titanium than do the orange regions. Mare Tranquillitatis, seen as a deep blue patch on the right, is richer in titanium than Mare Serenitatis, a slightly smaller circular area immediately adjacent to the upper left of Mare Tranquillitatis. Blue and orange areas covering much of the left side of the Moon in this view represent many separate lava flows in Oceanus Procellarum. The small purple areas found near the center are pyroclastic deposits formed by explosive volcanic eruptions. The fresh crater Tycho, with a diameter of 85 kilometers (53 miles), is prominent at the bottom of the photograph, where part of the Moon's disk is missing.

  14. Tidal dissipation in the large icy satellites: implications for their thermal evolution.

    NASA Astrophysics Data System (ADS)

    Tobie, G.; Mocquet, A.; Sotin, C.

    2003-04-01

    Tidal dissipation is a large heat source that controls the thermal evolution of several bodies of the Solar system, notably Europa and Titan. In order to investigate how tidal heating affects the present and past thermal states of these icy satellites, we perform numerical calculations of tidal dissipation distribution for different internal structures and different viscoelastic properties of their interiors. The numerical method is developed after the elastic formulation of free spheroidal oscillations of a compressible self-gravitating planet and adapted to a tidally forced viscoelastic response of the body. We test systematically the dependence of tidal dissipation on the rheological parameters namely, the viscosity eta, the shear modulus μ, and the bulk modulus K, as well as on the orbital parameters, i.e. the eccentricity e and the forcing frequency ω. The effects of tidal dissipation on heat balance in the outer icy layers are investigated with a 2D thermal convection model. We show that the tidal dissipation in the icy layers of Europa and Titan is very large, and that it allows for the long-term existence of a subsurface ocean below a convective ice I layer. We are also investigating thermal evolution models of the rocky core to address the question of tidal dissipation in the silicates. Although tidal dissipation in the rocky core is not required for an ocean to exist, it may provide an additional heating source for seafloor volcanism to occur. In addition, we show that the tidal dissipation in a floating icy layer mainly depends on its viscous structure and that the lateral viscosity variations modify the local dissipation and the value of the global dissipation up to 30%.

  15. Malapert Mountain: Gateway to the Moon

    NASA Astrophysics Data System (ADS)

    Schrunk, D.; Sharpe, B.

    The long lunar nights at the equatorial and mid-latitude regions of the Moon place severe limitations on the solar power and thermal management requirements of an unmanned lunar base. A solution to this problem is to locate sunlight-dependent facilities in polar regions, where nights can be very short due to chance interactions of lunar topography and orbital mechanics. Based on analyses of Clementine and Earth-based radar imaging of the Moon, the authors conclude that the summit of Malapert Mountain near the South Pole has the best combination of factors for a sunlight-dependent lunar base. Using a commercial software product, they determined that the Mountain summit receives full or partial sunlight for 93% of the lunar year and always has the Earth in view for direct Earth-Moon communications. By exploiting these optimum conditions, a remotely operated base at the summit could coordinate the scientific exploration of the entire south polar region. The base could also expedite the development of a permanent utility infrastructure and of facilities for human settlement. The authors conclude that the fortuitous and highly advantageous combination of physical factors of Malapert Mountain makes it the optimum site for beginning the human exploration and settlement of the Moon.

  16. Malapert mountain: Gateway to the moon

    NASA Astrophysics Data System (ADS)

    Sharpe, Burton L.; Schrunk, David G.

    2003-06-01

    The long lunar nights at the equatorial and mid-latitude regions of the Moon place severe limitations on the solar power and thermal management requirements of an unmanned lunar base. A solution to this problem is to locate sunlight-dependent facilities in polar regions where nights can be very short due to chance interactions of lunar topography and orbital mechanics. Based on analyses of Clementine and Earth-based radar imaging of the Moon, the authors conclude that the summit of Malapert Mountain near the South Pole has the best combination of factors for a sunlight-dependent lunar base. Using a commercial software product, they determined that the Mountain summit receives full or partial sunlight for 93% of the lunar year and always has the Earth in view for direct Earth-Moon communications. By exploiting these optimum conditions, a remotely operated base at the summit could coordinate the scientific exploration of the entire south polar region. The base could also expedite the development of a permanent utility infrastructure and facilities for human settlement. The authors conclude that the fortuitous and highly advantageous combination of physical factors of Malapert Mountain makes it the optimum site for beginning the human exploration and settlement of the Moon.

  17. Radioactivity of the moon and planets

    NASA Astrophysics Data System (ADS)

    Surkov, Iu. A.

    The major results of studies of the radioactivity of the moon and terrestrial planets are reviewed. Measurements of the cosmogenic and natural radioactivity of the moon and Mars were obtained from planetary orbiter measurements, and those of Venus by in situ measurements, in addition to measurements of lunar samples brought back to earth. For the case of the moon, the Western maria on the near side are found to be the most radioactive areas, with highlands on both sides of the moon exhibiting lower radioactivity than the maria and lunar radioactivity levels in general less than those of the earth, which is correlated with different chemical compositions of the two bodies. The potassium, uranium and thorium contents of the landing sites of Veneras 8, 9 and 10 are shown to differ from each other, but be similar to those of terrestrial basalts, which they also resemble in density. Gamma-radiation and X-ray fluorescence measurements of Mars indicate the content of natural radioelements to be similar to that of the eruptive rocks of the earth crust, with Martian rocks of volcanic formations similar to terrestrial and lunar basalts, and those of the ancient terra formations more closely resembling the anorthosite-norite-troctolite association of the lunar highlands. It is pointed out that natural radioelements contents of all the bodies examined indicate a single chemical differentiation process, while cosmogenic radiation contents can aid in determining cosmic ray intensities as well as the sequences of geological events.

  18. Heliophysics From the Surface of the Moon

    NASA Astrophysics Data System (ADS)

    Kasper, Justin C.

    2012-05-01

    Heliophysics, a combination of the disciplines of solar physics, space physics, and space weather, is the study of the system composed of the Sun’s heliosphere and the objects that interact with it, including the moon. Heliophysics science has been tightly coupled with exploration since the beginning of the space program, as scientists work to both understand the physics of the Sun-Earth-Moon system and to develop predictive capabilities that enable operational planning for lunar, deep space, and eventually Mars missions. Renewed robotic and human exploration of the moon creates opportunities for several new classes of experiments on the lunar surface and in lunar orbit that will both provide real-time awareness of space weather conditions during manned missions and advance the field of heliophysics science. The purpose of this talk is to summarize the scientific motivations and exploration benefits of heliophysics science experiments described in the 2007 NASA report “Heliophysics Science and the Moon: Potential Solar and Space Physics Science for Lunar Exploration”. A series of potential experiments will be discussed, ranging from small dust and particle sensors to sophisticated radio and optical telescopes.

  19. Changing Perspectives on Mercury and the Moon

    NASA Astrophysics Data System (ADS)

    Denevi, Brett W.

    2015-11-01

    Airless, cratered, and not so different in size, the Moon and Mercury form a natural pair in the inner Solar System. For decades after the 1974 and 1975 Mariner 10 flybys of Mercury, with little compositional information, no concrete evidence for volcanism, and images of less than half of the planet, it was thought that Mercury’s surface may be similar to the lunar highlands: an ancient anorthositic flotation crust subsequently shaped mainly by impact cratering. However, observations from the recently completed MESSENGER mission to Mercury have upended our view of the innermost planet, revealing, for example, a crust that may be rich in graphite and that has been extensively resurfaced by volcanic activity, and geologic activity that may continue today to produce enigmatic “hollows” - a crust very different from that of the Moon. Meanwhile, the Moon has undergone its own revolution, as data from recent spacecraft such as the Lunar Reconnaissance Orbiter reveal sites of silicic volcanism indicative of complex differentiation in the mantle, tectonic activity that may be ongoing, recent volcanic activity that alters the paradigm that volcanism died on the Moon over a billion years ago, and evidence that the early chronology of the inner Solar System may not be as well known as once thought. As our views of these two bodies evolve, a new understanding of their differences informs our knowledge of the variety of processes and styles of planetary evolution, and their similarities point to commonalities among all airless bodies.

  20. Santa and the Moon

    NASA Astrophysics Data System (ADS)

    Barthel, P.

    2012-05-01

    This article reflects on the use of illustrations of the Moon in images of Santa Claus, on Christmas gift-wrapping paper and in children's books, in two countries which have been important in shaping the image of Santa Claus and his predecessor Sinterklaas: the USA and the Netherlands. The appearance of the Moon in Halloween illustrations is also considered. The lack of either knowledge concerning the physical origin of the Moon's phases, or interest in understanding them, is found to be widespread in the Netherlands, but is also clearly present in the USA, and is quite possibly global. Certainly incomplete, but surely representative, lists that compile occurrences of both scientifically correct and scientifically incorrect gift- wrapping paper and children's books are also presented.

  1. Moon - North Pole Mosaic

    NASA Technical Reports Server (NTRS)

    1992-01-01

    This view of the Moon's north pole is a mosaic assembled from 18 images taken by Galileo's imaging system through a green filter as the spacecraft flew by on December 7, 1992. The left part of the Moon is visible from Earth; this region includes the dark, lava-filled Mare Imbrium (upper left); Mare Serenitatis (middle left); Mare Tranquillitatis (lower left), and Mare Crisium, the dark circular feature toward the bottom of the mosaic. Also visible in this view are the dark lava plains of the Marginis and Smythii Basins at the lower right. The Humboldtianum Basin, a 650-kilometer (400-mile) impact structure partly filled with dark volcanic deposits, is seen at the center of the image. The Moon's north pole is located just inside the shadow zone, about a third of the way from the top left of the illuminated region.

  2. LRO Enters Lunar Orbit (Highlights) - Duration: 2 minutes, 33 seconds.

    NASA Video Gallery