Nuclear radiation environment analysis for thermoelectric outer planet spacecraft

NASA Technical Reports Server (NTRS)

Davis, H. S.; Koprowski, E. F.

1972-01-01

Neutron and gamma ray transport calculations were performed using Monte Carlo methods and a three-dimensional geometric model of the spacecraft. The results are compared with similar calculations performed for an earlier design.

Quarantine constraints as applied to satellites

NASA Technical Reports Server (NTRS)

Hoffman, A. R.; Stavro, W.; Gonzalez, C. C.

1973-01-01

Plans for unmanned missions to planets beyond Mars in the 1970s include satellite encounters. Recently published observations of data for Titan, a satellite of Saturn, indicate that conditions may be hospitable for the growth of microorganisms. Therefore, the problem of satisfying possible quarantine constraints for outer planet satellites was investigated. This involved determining the probability of impacting a satellite of Jupiter or Saturn by a spacecraft for a planned satellite encounter during an outer planet mission. Mathematical procedures were formulated which determine the areas in the aim-plane that would result in trajectories that impact the satellite and provide a technique for numerically integrating the navigation error function over the impact area to obtain impact probabilities. The results indicate which of the planned spacecraft trajectory correction maneuvers are most critical in terms of satellite quarantine violation.

Trajectory correction propulsion for TOPS

NASA Technical Reports Server (NTRS)

Long, H. R.; Bjorklund, R. A.

1972-01-01

A blowdown-pressurized hydrazine propulsion system was selected to provide trajectory correction impulse for outer planet flyby spacecraft as the result of cost/mass/reliability tradeoff analyses. Present hydrazine component and system technology and component designs were evaluated for application to the Thermoelectric Outer Planet Spacecraft (TOPS); while general hydrazine technology was adequate, component design changes were deemed necessary for TOPS-type missions. A prototype hydrazine propulsion system was fabricated and fired nine times for a total of 1600 s to demonstrate the operation and performance of the TOPS propulsion configuration. A flight-weight trajectory correction propulsion subsystem (TCPS) was designed for the TOPS based on actual and estimated advanced components.

Outer-Planet Mission Analysis Using Solar-Electric Ion Propulsion

NASA Technical Reports Server (NTRS)

Woo, Byoungsam; Coverstone, Victoria L.; Hartmann, John W.; Cupples, Michael

2003-01-01

Outer-planet mission analysis was performed using three next generation solar-electric ion thruster models. Optimal trajectories are presented that maximize the delivered mass to the designated outer planet. Trajectories to Saturn and Neptune with a single Venus gravity assist are investigated. For each thruster model, the delivered mass versus flight time curve was generated to obtain thruster model performance. The effects of power to the thrusters and resonance ratio of Venutian orbital periods to spacecraft period were also studied. Multiple locally optimal trajectories to Saturn and Neptune have been discovered in different regions of the parameter search space. The characteristics of each trajectory are noted.

Self sterilization of bodies during outer planet entry. [atmospheric temperature effects

NASA Technical Reports Server (NTRS)

Hoffman, A. R.; Jaworski, W.; Taylor, D. M.

1975-01-01

As a body encounters the atmosphere of an outer planet, whether accidentally or by plan, it will be subjected to heat loads which could result in high temperature conditions that render terrestrial organisms on or within the body non-viable. To determine whether an irregularly shaped entering body, consisting of several different materials, would be sterilized during inadvertent entry at high velocity, the thermal response of a typical outer planet spacecraft instrument was studied. The results indicate that the Teflon-insulated cable and electronic circuit boards may not experience sterilizing temperatures during a Jupiter, Saturn, or Titan entry. Another conclusion of the study is that small plastic particles entering Saturn from outer space have wider survival corridors than do those at Jupiter.

Onboard Image Processing for Autonomous Spacecraft Detection of Volcanic Plumes

NASA Astrophysics Data System (ADS)

Thompson, D. R.; Bunte, M.; Castaño, R.; Chien, S.; Greeley, R.

2011-03-01

Onboard spacecraft image processing could enable long-term monitoring for volcanic plume activity in the outer planets. A new plume detection technique shows strong performance on images of Enceladus and Io taken by Cassini, Voyager, and Galileo.

Planetary quarantine: Principles, methods, and problems

NASA Technical Reports Server (NTRS)

Hall, L. B.

1975-01-01

Requirements for planetary quarantine programs focus on microbial life forms as the primary contamination threat carried by spacecraft to a planet, or back to earth from another planet or outer space. Constraints on planetary flight missions and forthcoming Martian landings are depicted.

Quarantine constraints as applied to satellites.

NASA Technical Reports Server (NTRS)

Hoffman, A. R.; Stavro, W.; Gonzalez, C.

1973-01-01

Plans for unmanned missions to planets beyond Mars in the 1970s include satellite encounters. Recently published observations of data for Titan, a satellite of Saturn, indicate that conditions may be hospitable for the growth of microorganisms. Therefore, the problem of satisfying possible quarantine constraints for outer planet satellites was investigated. This involved determining the probability of impacting a satellite of Jupiter or Saturn by a spacecraft for a planned satellite encounter during an outer planet mission. Mathematical procedures were formulated which (1) determine the areas in the aim-plane that would result in trajectories that impact the satellite and (2) provide a technique for numerically integrating the navigation error function over the impact area to obtain impact probabilities. The results indicate which of the planned spacecraft trajectory correction maneuvers are most critical in terms of satellite quarantine violation.

Explosive-actuated valve design concept that eliminates blow-by. [for the TOPS spacecraft trajectory correction propulsion subsystem

NASA Technical Reports Server (NTRS)

Hagler, R., Jr.

1974-01-01

A method of evaluating the normally open normally closed, explosive actuated valves that were selected for use in the trajectory correction propulsion subsystem of the Thermoelectric Outer Planet Spacecraft (TOPS) program is presented. The design philosophy which determined the requirements for highly reliable valves that could provide the performance capability during long duration (10 year) missions to the outer planets is discussed. The techniques that were used to fabricate the valves and manifold ten valves into an assembly with the capability of five propellant-flow initiation/isolation sequences are described. The test program, which was conducted to verify valve design requirements, is outlined and the more significant results are shown.

Power conditioning equipment for a thermoelectric outer planet spacecraft, volume 1, book 2

NASA Technical Reports Server (NTRS)

Andrews, R. E. (Editor)

1972-01-01

The design and development of power conditioning equipment for the thermoelectric outer planet spacecraft program are considered. One major aspect of the program included the design, assembly and test of various breadboard power conditioning elements. Among others these included a quad-redundant shunt regulator, a high voltage traveling wave tube dc-to-dc converter, two-phase gyro inverters and numerous solid state switching circuits. Many of these elements were arranged in a typical subsystem configuration and tests were conducted which demonstrated basic element compatibility. In parallel with the development of the basic power conditioning elements, system studies were continued. The salient features of the selected power subsystem configuration are presented.

Magnetour: Surfing planetary systems on electromagnetic and multi-body gravity fields

NASA Astrophysics Data System (ADS)

Lantoine, Gregory; Russell, Ryan P.; Anderson, Rodney L.; Garrett, Henry B.

2017-09-01

A comprehensive tour of the complex outer planet systems is a central goal in space science. However, orbiting multiple moons of the same planet would be extremely prohibitive using traditional propulsion and power technologies. In this paper, a new mission concept, named Magnetour, is presented to facilitate the exploration of outer planet systems and address both power and propulsion challenges. This approach would enable a single spacecraft to orbit and travel between multiple moons of an outer planet, without significant propellant or onboard power source. To achieve this free-lunch 'Grand Tour', Magnetour exploits the unexplored combination of magnetic and multi-body gravitational fields of planetary systems, with a unique focus on using a bare electrodynamic tether for power and propulsion. Preliminary results indicate that the Magnetour concept is sound and is potentially highly promising at Jupiter.

Guidance and Navigation Requirements for Unmanned Flyby and Swingby Missions to the Outer Planets. Volume 3; Low Thrust Missions, Phase B

NASA Technical Reports Server (NTRS)

1970-01-01

The guidance and navigation requirements for unmanned missions to the outer planets, assuming constant, low thrust, ion propulsion are discussed. The navigational capability of the ground based Deep Space Network is compared to the improvements in navigational capability brought about by the addition of guidance and navigation related onboard sensors. Relevant onboard sensors include: (1) the optical onboard navigation sensor, (2) the attitude reference sensors, and (3) highly sensitive accelerometers. The totally ground based, and the combination ground based and onboard sensor systems are compared by means of the estimated errors in target planet ephemeris, and the spacecraft position with respect to the planet.

Voyager Outreach Compilation

NASA Technical Reports Server (NTRS)

1998-01-01

This NASA JPL (Jet Propulsion Laboratory) video presents a collection of the best videos that have been published of the Voyager mission. Computer animation/simulations comprise the largest portion of the video and include outer planetary magnetic fields, outer planetary lunar surfaces, and the Voyager spacecraft trajectory. Voyager visited the four outer planets: Jupiter, Saturn, Uranus, and Neptune. The video contains some live shots of Jupiter (actual), the Earth's moon (from orbit), Saturn (actual), Neptune (actual) and Uranus (actual), but is mainly comprised of computer animations of these planets and their moons. Some of the individual short videos that are compiled are entitled: The Solar System; Voyage to the Outer Planets; A Tour of the Solar System; and the Neptune Encounter. Computerized simulations of Viewing Neptune from Triton, Diving over Neptune to Meet Triton, and Catching Triton in its Retrograde Orbit are included. Several animations of Neptune's atmosphere, rotation and weather features as well as significant discussion of the planet's natural satellites are also presented.

Radioisotope Electric Propulsion for Fast Outer Planetary Orbiters

NASA Technical Reports Server (NTRS)

Oleson, Steven; Benson, Scott; Gefert, Leon; Patterson, Michael; Schreiber, Jeffrey

2002-01-01

Recent interest in outer planetary targets by the Office of Space Science has spurred the search for technology options to enable relatively quick missions to outer planetary targets. Several options are being explored including solar electric propelled stages combined with aerocapture at the target and nuclear electric propulsion. Another option uses radioisotope powered electric thrusters to reach the outer planets. Past work looked at using this technology to provide faster flybys. A better use for this technology is for outer planet orbiters. Combined with medium class launch vehicles and a new direct trajectory these small, sub-kilowatt ion thrusters and Stirling radioisotope generators were found to allow missions as fast as 5 to 12 years for objects from Saturn to Pluto, respectively. Key to the development is light spacecraft and science payload technologies.

Planetary quarantine. Space research and technology

NASA Technical Reports Server (NTRS)

1973-01-01

The impact of satisfying satellite quarantine constraints on outer planet missions and spacecraft design are studied by considering the effects of planetary radiation belts, solar wind radiation, and space vacuum on microorganism survival. Post launch recontamination studies evaluate the effects of mission environments on particle distributions on spacecraft surfaces and effective cleaning and decontamination techniques.

Outer planet Pioneer imaging communications system study. [data compression

NASA Technical Reports Server (NTRS)

1974-01-01

The effects of different types of imaging data compression on the elements of the Pioneer end-to-end data system were studied for three imaging transmission methods. These were: no data compression, moderate data compression, and the advanced imaging communications system. It is concluded that: (1) the value of data compression is inversely related to the downlink telemetry bit rate; (2) the rolling characteristics of the spacecraft limit the selection of data compression ratios; and (3) data compression might be used to perform acceptable outer planet mission at reduced downlink telemetry bit rates.

Planetary quarantine: Space research and technology

NASA Technical Reports Server (NTRS)

1974-01-01

The impact of satisfying satellite quarantine constraints on current outer planet mission and spacecraft designs is considered. Tools required to perform trajectory and navigation analyses for determining satellite impact probabilities are developed.

Planetary quarantine, supporting research and technology

NASA Technical Reports Server (NTRS)

1975-01-01

The impact of satisfying satellite quarantine on current outer planet mission and spacecraft designs was determined and the tools required to perform trajectory and navigation analyses for determining satellite impact probabilities were developed.

JPL-20170720-VOYAGEs-0001-Voyager Media Reel 3

NASA Image and Video Library

2017-07-20

The continuing mission of Voyager 1 and Voyager 2 to Jupiter, Saturn, Uranus, Neptune and interstellar space is documented. Included: construction and launch of the spacecraft. Movies made by the spacecraft. Animation of the Voyagers at the outer planets. A description of the "solar system portrait." The sounds recorded by Voyager 1 passing through dense interstellar plasma.

Analysis of selected deep space missions

NASA Technical Reports Server (NTRS)

West, W. S.; Holman, M. L.; Bilsky, H. W.

1971-01-01

Task 1 of the NEW MOONS (NASA Evaluation With Models of Optimized Nuclear Spacecraft) study is discussed. Included is an introduction to considerations of launch vehicles, spacecraft, spacecraft subsystems, and scientific objectives associated with precursory unmanned missions to Jupiter and thence out of the ecliptic plane, as well as other missions to Jupiter and other outer planets. Necessity for nuclear power systems is indicated. Trajectories are developed using patched conic and n-body computer techniques.

Potential advantages of solar electric propulsion for outer planet orbiters.

NASA Technical Reports Server (NTRS)

Sauer, C. G.; Atkins, K. L.

1972-01-01

Past studies of solar electric propulsion for outer planet orbiters have generally emphasized the advantages of flight time reduction and payload increases. However, several subtle advantages exist, which may become important in an environment of increasingly difficult requirements as ways to extend current technology are sought. These advantages accrue primarily because of the inherent capability, unique to electric propulsion, to efficiently shape a trajectory while enroute. Stressed in this paper are: the ability to meet orbital constraints due to assumed radiation belts, science flexibility in a dual launch program, increased numbers of observational passes, and the lengthening of launch periods. These are examined for years representative of relatively easy and difficult ballistic missions. The results indicate that an early investment in solar electric technology will provide a strong performance foundation for a long range outer planet exploration program which evolves from current spacecraft technology.

Selection and Prioritization of Advanced Propulsion Technologies for Future Space Missions

NASA Technical Reports Server (NTRS)

Eberle, Bill; Farris, Bob; Johnson, Les; Jones, Jonathan; Kos, Larry; Woodcock, Gordon; Brady, Hugh J. (Technical Monitor)

2002-01-01

The exploration of our solar system will require spacecraft with much greater capability than spacecraft which have been launched in the past. This is particularly true for exploration of the outer planets. Outer planet exploration requires shorter trip times, increased payload mass, and ability to orbit or land on outer planets. Increased capability requires better propulsion systems, including increased specific impulse. Chemical propulsion systems are not capable of delivering the performance required for exploration of the solar system. Future propulsion systems will be applied to a wide variety of missions with a diverse set of mission requirements. Many candidate propulsion technologies have been proposed but NASA resources do not permit development of a] of them. Therefore, we need to rationally select a few propulsion technologies for advancement, for application to future space missions. An effort was initiated to select and prioritize candidate propulsion technologies for development investment. The results of the study identified Aerocapture, 5 - 10 KW Solar Electric Ion, and Nuclear Electric Propulsion as high priority technologies. Solar Sails, 100 Kw Solar Electric Hall Thrusters, Electric Propulsion, and Advanced Chemical were identified as medium priority technologies. Plasma sails, momentum exchange tethers, and low density solar sails were identified as high risk/high payoff technologies.

Petit Grand Tour: Mission Concepts to Outer Planet Satellites Using Non-Conic Low Energy Trajectories

NASA Technical Reports Server (NTRS)

Lo, M. W.

2001-01-01

Our Solar System is connected by a vast Interplanetary Superhighway System (ISSys) providing low energy transport throughout. The Outer Planets with their satellites and rings are smaller replicas of the Solar System with their own ISSys, also providing low energy transport within their own satellite systems. This low energy transport system is generated by all of the Lagrange points of the planets and satellites within the Solar System. Figures show the tubular passage-ways near L1 of Jupiter and the ISSys of Jupiter schematically. These delicate and resilient dynamics may be used to great effect to produce free temporary captures of a spacecraft by a planet or satellite, low energy interplanetary and inter-satellite transfers, as well as precision impact orbits onto the surface of the satellites. Additional information is contained in the original extended abstract.

Feasibility of infrared Earth tracking for deep-space optical communications.

PubMed

Chen, Yijiang; Hemmati, Hamid; Ortiz, Gerry G

2012-01-01

Infrared (IR) Earth thermal tracking is a viable option for optical communications to distant planet and outer-planetary missions. However, blurring due to finite receiver aperture size distorts IR Earth images in the presence of Earth's nonuniform thermal emission and limits its applicability. We demonstrate a deconvolution algorithm that can overcome this limitation and reduce the error from blurring to a negligible level. The algorithm is applied successfully to Earth thermal images taken by the Mars Odyssey spacecraft. With the solution to this critical issue, IR Earth tracking is established as a viable means for distant planet and outer-planetary optical communications. © 2012 Optical Society of America

Space Photography 1977 Index

NASA Technical Reports Server (NTRS)

1976-01-01

An index is provided to representative photographs and transparencies available from NASA. Subjects include spacecraft, astronauts, lunar surface, planets and outer space phenomena, earth observations, and aviation. High altitude aircraft infrared photographs are included along with artists' conceptions of space shuttle and space colonies.

Outer planet atmospheric entry probes - An overview of technology readiness

NASA Technical Reports Server (NTRS)

Vojvodich, N. S.; Reynolds, R. T.; Grant, T. L.; Nachtsheim, P. R.

1975-01-01

Entry probe systems for characterizing, by in situ measurements, the atmospheric properties, chemical composition, and cloud structure of the planets Saturn, Uranus, and Jupiter are examined from the standpoint of unique mission requirements, associated subsystem performance, and degree of commonality of design. Past earth entry vehicles (PAET) and current planetary spacecraft (Pioneer Venus probes and Viking lander) are assessed to identify the extent of potential subsystem inheritance, as well as to establish the significant differences, in both form and function, relative to outer planet requirements. Recent research results are presented and reviewed for the most critical probe technology areas, including: science accommodation, telecommunication, and entry heating and thermal protection. Finally presented is a brief discussion of the use of decision analysis techniques for quantifying various probe heat-shield test alternatives and performance risk.

The Voyager spacecraft /James Watt International Gold Medal Lecture/

NASA Technical Reports Server (NTRS)

Heacock, R. L.

1980-01-01

The Voyager Project background is reviewed with emphasis on selected features of the Voyager spacecraft. Investigations by the Thermo-electric Outer Planets Spacecraft Project are discussed, including trajectories, design requirements, and the development of a Self Test and Repair computer, and a Computer Accessed Telemetry System. The design and configuration of the spacecraft are described, including long range communications, attitude control, solar independent power, sequencing and control data handling, and spacecraft propulsion. The development program, maintained by JPL, experienced a variety of problems such as design deficiencies, and process control and manufacturing problems. Finally, the spacecraft encounter with Jupiter is discussed, and expectations for the Saturn encounter are expressed.

Voyager: The grandest tour. The mission to the outer planets

NASA Astrophysics Data System (ADS)

1991-04-01

A history and general accomplishments of the Voyager 1 and 2 missions to the outer planets are presented. Over the course of 12 years, these spacecraft drew back the curtain on nearly half the solar system. They brought into sharp focus the faces of the four giant outer planets - Jupiter, Saturn, Uranus, and Neptune - and their families of disparate moons. The Voyagers showed us unimagined worlds: frozen beauty in the rings of Saturn, and molten violence in the explosive sulfur volcanoes on Jupiter's moon Io. They brought us close-ups of the florid and intricate storms of Jupiter itself. Voyager 2 went on to reveal the peculiarities of cockeyed Uranus and its equally skewed rings and moons. Then finally, Neptune, nearly invisible from earth, was unveiled in all its big, blue splendor, circled by shadowy rings and a bright pastel moon called Triton. Both Voyagers are headed toward the outer boundary of the solar system in search of the heliopause, the region where the sun's influence wanes and the beginning of interstellar space can be sensed.

Voyager: The grandest tour. The mission to the outer planets

NASA Technical Reports Server (NTRS)

1991-01-01

A history and general accomplishments of the Voyager 1 and 2 missions to the outer planets are presented. Over the course of 12 years, these spacecraft drew back the curtain on nearly half the solar system. They brought into sharp focus the faces of the four giant outer planets - Jupiter, Saturn, Uranus, and Neptune - and their families of disparate moons. The Voyagers showed us unimagined worlds: frozen beauty in the rings of Saturn, and molten violence in the explosive sulfur volcanoes on Jupiter's moon Io. They brought us close-ups of the florid and intricate storms of Jupiter itself. Voyager 2 went on to reveal the peculiarities of cockeyed Uranus and its equally skewed rings and moons. Then finally, Neptune, nearly invisible from earth, was unveiled in all its big, blue splendor, circled by shadowy rings and a bright pastel moon called Triton. Both Voyagers are headed toward the outer boundary of the solar system in search of the heliopause, the region where the sun's influence wanes and the beginning of interstellar space can be sensed.

Fault tolerant, radiation hard, high performance digital signal processor

NASA Technical Reports Server (NTRS)

Holmann, Edgar; Linscott, Ivan R.; Maurer, Michael J.; Tyler, G. L.; Libby, Vibeke

1990-01-01

An architecture has been developed for a high-performance VLSI digital signal processor that is highly reliable, fault-tolerant, and radiation-hard. The signal processor, part of a spacecraft receiver designed to support uplink radio science experiments at the outer planets, organizes the connections between redundant arithmetic resources, register files, and memory through a shuffle exchange communication network. The configuration of the network and the state of the processor resources are all under microprogram control, which both maps the resources according to algorithmic needs and reconfigures the processing should a failure occur. In addition, the microprogram is reloadable through the uplink to accommodate changes in the science objectives throughout the course of the mission. The processor will be implemented with silicon compiler tools, and its design will be verified through silicon compilation simulation at all levels from the resources to full functionality. By blending reconfiguration with redundancy the processor implementation is fault-tolerant and reliable, and possesses the long expected lifetime needed for a spacecraft mission to the outer planets.

The effects of radiation on the outer planets grand tour

NASA Technical Reports Server (NTRS)

1971-01-01

A handbook is presented which was designed to accompany an oral presentation on the effects of radiation on the outer planets grand tour (OPGT). A summary of OPGT radiation environments expected from natural sources and the radioisotope thermoelectric generators and basic radiation effects and processes are reviewed, and ionization and displacement effects are examined. The presentation summarizes the effects of radiation on miscellaneous spacecraft materials and devices. The annealing and hardening of electronics are described. Special emphasis is placed on microcircuits. Mathematical modeling of circuits affected by radiation and radiation environmental testing are discussed. A review of means of evaluating the performance and correcting failures of irradiated devices is also presented.

Earth's magnetosphere and outer radiation belt under sub-Alfvénic solar wind

PubMed Central

Lugaz, Noé; Farrugia, Charles J.; Huang, Chia-Lin; Winslow, Reka M.; Spence, Harlan E.; Schwadron, Nathan A.

2016-01-01

The interaction between Earth's magnetic field and the solar wind results in the formation of a collisionless bow shock 60,000–100,000 km upstream of our planet, as long as the solar wind fast magnetosonic Mach (hereafter Mach) number exceeds unity. Here, we present one of those extremely rare instances, when the solar wind Mach number reached steady values <1 for several hours on 17 January 2013. Simultaneous measurements by more than ten spacecraft in the near-Earth environment reveal the evanescence of the bow shock, the sunward motion of the magnetopause and the extremely rapid and intense loss of electrons in the outer radiation belt. This study allows us to directly observe the state of the inner magnetosphere, including the radiation belts during a type of solar wind-magnetosphere coupling which is unusual for planets in our solar system but may be common for close-in extrasolar planets. PMID:27694887

Earth's magnetosphere and outer radiation belt under sub-Alfvénic solar wind.

PubMed

Lugaz, Noé; Farrugia, Charles J; Huang, Chia-Lin; Winslow, Reka M; Spence, Harlan E; Schwadron, Nathan A

2016-10-03

The interaction between Earth's magnetic field and the solar wind results in the formation of a collisionless bow shock 60,000-100,000 km upstream of our planet, as long as the solar wind fast magnetosonic Mach (hereafter Mach) number exceeds unity. Here, we present one of those extremely rare instances, when the solar wind Mach number reached steady values <1 for several hours on 17 January 2013. Simultaneous measurements by more than ten spacecraft in the near-Earth environment reveal the evanescence of the bow shock, the sunward motion of the magnetopause and the extremely rapid and intense loss of electrons in the outer radiation belt. This study allows us to directly observe the state of the inner magnetosphere, including the radiation belts during a type of solar wind-magnetosphere coupling which is unusual for planets in our solar system but may be common for close-in extrasolar planets.

Benefits of Nuclear Electric Propulsion for Outer Planet Exploration

NASA Technical Reports Server (NTRS)

Kos, Larry; Johnson, Les; Jones, Jonathan; Trausch, Ann; Eberle, Bill; Woodcock, Gordon; Brady, Hugh J. (Technical Monitor)

2002-01-01

Nuclear electric propulsion (NEP) offers significant benefits to missions for outer planet exploration. Reaching outer planet destinations, especially beyond Jupiter, is a struggle against time and distance. For relatively near missions, such as a Europa lander, conventional chemical propulsion and NEP offer similar performance and capabilities. For challenging missions such as a Pluto orbiter, neither chemical nor solar electric propulsion are capable while NEP offers acceptable performance. Three missions are compared in this paper: Europa lander, Pluto orbiter, and Titan sample return, illustrating how performance of conventional and advanced propulsion systems vary with increasing difficulty. The paper presents parametric trajectory performance data for NEP. Preliminary mass/performance estimates are provided for a Europa lander and a Titan sample return system, to derive net payloads for NEP. The NEP system delivers payloads and ascent/descent spacecraft to orbit around the target body, and for sample return, delivers the sample carrier system from Titan orbit to an Earth transfer trajectory. A representative scientific payload 500 kg was assumed, typical for a robotic mission. The resulting NEP systems are 100-kWe class, with specific impulse from 6000 to 9000 seconds.

Mariner Jupiter/Saturn 1977 - The mission frame.

NASA Technical Reports Server (NTRS)

Bourke, R. D.; Miles, R. F., Jr.; Penzo, P. A.; Van Dillen, S. L.; Wallace, R. A.

1972-01-01

Following the cancellation of the Outer Planet Grand Tour Project, NASA and JPL examined less ambitious, alternative missions for exploring the outer planets. The mission that proved most attractive scientifically and fits within the projected NASA budget constraints embraces dual flights to Jupiter and Saturn, with launch in 1977. NASA has implemented it as the Mariner Jupiter/Saturn 1977 (MJS77) Project. The MJS77 mission covers exploratory investigations of the Jupiter and Saturn planetary systems and the interplanetary medium out to Saturn. Items of special interest include Jupiter's great red spot, the question of Io's anomalous brightening and phenomena associated with its EM behavior. After Saturn encounter, the spacecraft will escape the solar system in the general direction of the solar apex.

Outer Planet Exploration with Advanced Radioisotope Electric Propulsion

NASA Technical Reports Server (NTRS)

Oleson, Steven; Gefert, Leon; Patterson, Michael; Schreiber, Jeffrey; Benson, Scott; McAdams, Jim; Ostdiek, Paul

2002-01-01

In response to a request by the NASA Deep Space Exploration Technology Program, NASA Glenn Research Center conducted a study to identify advanced technology options to perform a Pluto/Kuiper mission without depending on a 2004 Jupiter Gravity Assist, but still arriving before 2020. A concept using a direct trajectory with small, sub-kilowatt ion thrusters and Stirling radioisotope power systems was shown to allow the same or smaller launch vehicle class as the chemical 2004 baseline and allow a launch slip and still flyby in the 2014 to 2020 timeframe. With this promising result the study was expanded to use a radioisotope power source for small electrically propelled orbiter spacecraft for outer planet targets such as Uranus, Neptune, and Pluto.

Spacecraft microbial burden reduction due to atmospheric entry heating: Jupiter

NASA Technical Reports Server (NTRS)

Gonzalez, C. C.; Jaworski, W.; Mcronald, A. S.; Hoffman, A. R.

1973-01-01

Planetary quarantine analyses performed for recent unmanned Mars and Venus missions assumed that the probability of contamination by a spacecraft given accidental impact was equivalent to one. However, in the case of the gaseous outer planets, the heat generated during the inadvertent entry of a spacecraft into the planetary atmosphere might be sufficient to cause significant microbial burden reduction. This could affect navigation strategy by reducing the necessity for biasing the aim point away from the planets. An effort has been underway to develop the tools necessary to predict temperature histories for a typical spacecraft during inadvertent entry. In order that the results have general applicability, parametric analyses were performed. The thermal response of the spacecraft components and debris resulting from disintegration was determined. The temperature histories of small particles and composite materials, such as thermal blankets and an antenna, were given special attention. Guidelines are given to indicate the types of components and debris most likely to contain viable organisms, which could contaminate the lower layers of the Jovian atmosphere (approximately one atmosphere of pressure).

Technology requirements for a generic aerocapture system. [for atmospheric entry

NASA Technical Reports Server (NTRS)

Cruz, M. I.

1980-01-01

The technology requirements for the design of a generic aerocapture vehicle system are summarized. These spacecraft have the capability of completely eliminating fuel-costly retropropulsion for planetary orbit capture through a single aerodynamically controlled atmospheric braking pass from a hyperbolic trajectory into a near circular orbit. This generic system has application at both the inner and outer planets. Spacecraft design integration, navigation, communications, and aerothermal protection system design problems were assessed in the technology requirements study and are discussed in this paper.

NASA Facts: an Educational Publication of the National Aeronautics and Space Administration. the Voyager Mission. [Jupiter probes

NASA Technical Reports Server (NTRS)

1979-01-01

The evolution of Jupiter, as well as its rotation, atmosphere and magnetosphere are described in this third in a series of publications on the exploration of the outer planets by the Voyager spacecraft. Activities for student participation are included with a selected reading list.

Voyager to Jupiter and Saturn

NASA Technical Reports Server (NTRS)

1977-01-01

The NASA Voyager mission to explore planets of the outer solar system is summarized. The mission schedule and profiles for encounters with Jupiter and Saturn, and possibly with Uranus and Pluto are included along with a description of the spacecraft and its trajectories. Scientific investigations to be made and the instruments carried are also discussed.

Power conditioning equipment for a thermoelectric outer planet spacecraft, volume 1, book 1

NASA Technical Reports Server (NTRS)

Andrews, R. E. (Editor)

1972-01-01

Equipment was designed to receive power from a radioisotope thermoelectric generator source, condition, distribute, and control this power for the spacecraft loads. The TOPS mission, aimed at a representative tour of the outer planets, would operate for an estimated 12 year period. Unique design characteristics required for the power conditioning equipment results from the long mission time and the need for autonomous on-board operations due to large communications distances and the associated time delays of ground initiated actions. The salient features of the selected power subsystem configuration are: (1) The PCE regulates the power from the radioisotope thermoelectric generator power source at 30 vdc by means of a quad-redundant shunt regulator; (2) 30 vdc power is used by certain loads, but is more generally inverted and distributed as square-wave ac power; (3) a protected bus is used to assure that power is always available to the control computer subsystem to permit corrective action to be initiated in response to fault conditions; and (4) various levels of redundancy are employed to provide high subsystem reliability.

Algorithms for Autonomous Plume Detection on Outer Planet Satellites

NASA Astrophysics Data System (ADS)

Lin, Y.; Bunte, M. K.; Saripalli, S.; Greeley, R.

2011-12-01

We investigate techniques for automated detection of geophysical events (i.e., volcanic plumes) from spacecraft images. The algorithms presented here have not been previously applied to detection of transient events on outer planet satellites. We apply Scale Invariant Feature Transform (SIFT) to raw images of Io and Enceladus from the Voyager, Galileo, Cassini, and New Horizons missions. SIFT produces distinct interest points in every image; feature descriptors are reasonably invariant to changes in illumination, image noise, rotation, scaling, and small changes in viewpoint. We classified these descriptors as plumes using the k-nearest neighbor (KNN) algorithm. In KNN, an object is classified by its similarity to examples in a training set of images based on user defined thresholds. Using the complete database of Io images and a selection of Enceladus images where 1-3 plumes were manually detected in each image, we successfully detected 74% of plumes in Galileo and New Horizons images, 95% in Voyager images, and 93% in Cassini images. Preliminary tests yielded some false positive detections; further iterations will improve performance. In images where detections fail, plumes are less than 9 pixels in size or are lost in image glare. We compared the appearance of plumes and illuminated mountain slopes to determine the potential for feature classification. We successfully differentiated features. An advantage over other methods is the ability to detect plumes in non-limb views where they appear in the shadowed part of the surface; improvements will enable detection against the illuminated background surface where gradient changes would otherwise preclude detection. This detection method has potential applications to future outer planet missions for sustained plume monitoring campaigns and onboard automated prioritization of all spacecraft data. The complementary nature of this method is such that it could be used in conjunction with edge detection algorithms to increase effectiveness. We have demonstrated an ability to detect transient events above the planetary limb and on the surface and to distinguish feature classes in spacecraft images.

Open-systems Architecture of a Standardized Command Interface Chip-set for Switching and Control of a Spacecraft Power Bus

NASA Technical Reports Server (NTRS)

Ruiz, B. Ian; Burke, Gary R.; Lung, Gerald; Whitaker, William D.; Nowicki, Robert M.

2004-01-01

This viewgraph presentation reviews the architecture of the The CIA-AlA chip-set is a set of mixed-signal ASICs that provide a flexible high level interface between the spacecraft's command and data handling (C&DH) electronics and lower level functions in other spacecraft subsystems. Due to the open-systems architecture of the chip-set including an embedded micro-controller a variety of applications are possible. The chip-set was developed for the missions to the outer planets. The chips were developed to provide a single solution for both the switching and regulation of a spacecraft power bus. The Open-Systems Architecture allows for other powerful applications.

Automatic control in planetary exploration in the 1980s. [onboard spacecraft

NASA Technical Reports Server (NTRS)

Moore, J. W.

1973-01-01

Based on an examination of the planetary missions in the 1980s and their related objectives, a broad assessment of the automatic control capabilities required for these missions is presented. The ten outer-planet, terrestrial-planet, and small-body missions considered involve various operations encompassing a complex series of modes including cruise, maneuver, and powered flight control. In addition to routine navigation and attitude control, onboard control is required to point scientific instruments and antennas with respect to the vehicle and to maneuver the spacecraft in time-constrained or hazardous environments. These 1980 missions aimed at exploring new areas of the solar system will be more demanding. New design philosophies and increased performance capabilities will be required to meet the constraints imposed by science requirements and mission-cost effectiveness.

OPUS: A Comprehensive Search Tool for Remote Sensing Observations of the Outer Planets. Now with Enhanced Geometric Metadata for Cassini and New Horizons Optical Remote Sensing Instruments.

NASA Astrophysics Data System (ADS)

Gordon, M. K.; Showalter, M. R.; Ballard, L.; Tiscareno, M.; French, R. S.; Olson, D.

2017-06-01

The PDS RMS Node hosts OPUS - an accurate, comprehensive search tool for spacecraft remote sensing observations. OPUS supports Cassini: CIRS, ISS, UVIS, VIMS; New Horizons: LORRI, MVIC; Galileo SSI; Voyager ISS; and Hubble: ACS, STIS, WFC3, WFPC2.

(abstract) A Low-Cost Mission to 2060 Chiron Based on the Pluto Fast Flyby

NASA Technical Reports Server (NTRS)

Stern, S. A.; Salvo, C. G.; Wallace, R. A.; Weinstein, S. S.; Weissman, P. R.

1994-01-01

The Pluto Fast Flyby-based mission to Chiron described in this paper is a low cost, scientifically rewarding, focused mission in the outer solar system. The proposed mission will make a flyby of 2060 Chiron, an active 'comet' with over 10(sup 4) times the mass of Halley, and an eccentric, Saturn-crossing orbit which ranges from 8.5 to 19 AU. This mission concept achieves the flyby 4.2 years after launch on a direct trajectory from Earth, is independent of Jupiter launch windows, and fits within Discovery cost guidelines. This mission offers the scientific opportunity to examine a class of object left unsampled by the trail-blazing Mariners, Pioneers, Voyagers, and missions to Halley. Spacecraft reconnaissance of Chiron addresses unique objectives relating to cometary science, other small bodies, the structure of quasi-bound atmospheres on modest-sized bodies, and the origin of primitive bodies and the giant planets. Owing to Chiron's large size (180

Applications of the hybrid coordinate method to the TOPS autopilot

NASA Technical Reports Server (NTRS)

Fleischer, G. E.

1978-01-01

Preliminary results are presented from the application of the hybrid coordinate method to modeling TOPS (thermoelectric outer planet spacecraft) structural dynamics. Computer simulated responses of the vehicle are included which illustrate the interaction of relatively flexible appendages with an autopilot control system. Comparisons were made between simplified single-axis models of the control loop, with spacecraft flexibility represented by hinged rigid bodies, and a very detailed three-axis spacecraft model whose flexible portions are described by modal coordinates. While single-axis system, root loci provided reasonable qualitative indications of stability margins in this case, they were quantitatively optimistic when matched against responses of the detailed model.

Thermal structure and heat balance of the outer planets

NASA Technical Reports Server (NTRS)

Conrath, B. J.; Hanel, R. A.; Samuelson, R. E.

1989-01-01

Current knowledge of the thermal structure and energy balance of the outer planets is summarized. The Voyager spacecraft experiments have provided extensive new information on the atmospheric temperatures and energetics of Jupiter, Saturn and Uranus. All three planets show remarkably small global-scale horizontal thermal contrast, indicating efficient redistribution of heat within the atmospheres or interiors. Horizontal temperature gradients on the scale of the zonal jets indicate that the winds decay with height in the upper troposphere. This suggests that the winds are driven at deeper levels and are subjected to frictional damping of unknown origin at higher levels. Both Jupiter and Saturn have internal power sources equal to about 70 percent of the absorbed solar power. This result is consistent with the view that significant helium differentiation has occurred on Saturn. Uranus has an internal power no greater than 13 percent of the absorbed solar power, while earth-based observations suggest Neptune has an internal power in excess of 100 percent of the absorbed solar power.

Voyager 2 Uranus and Neptune targeting

NASA Technical Reports Server (NTRS)

Gray, D. L.; Cesarone, R. J.; Van Allen, R. E.

1982-01-01

Targeting strategies are developed for the Voyager 2 flybys of Uranus and Neptune/Triton. The need to maximize science return, conserve propellant, and maintain spacecraft safety presents a challenge, given the difficulty in estimating the spacecraft orbit relative to these outer planets. Expected propellant usage, science return, and targeting complexity are presented for each targeting strategy. For the dual encounter of Neptune and its satellite Triton, split targeting conditions are proposed to fix the most important conditions at each body, and thus minimize science losses resulting from Triton ephemeris uncertainties.

Nuclear Thermal Rocket (NTR) Propulsion and Power Systems for Outer Planetary Exploration Missions

NASA Technical Reports Server (NTRS)

Borowski, S. K.; Cataldo, R. L.

2001-01-01

The high specific impulse (I (sub sp)) and engine thrust generated using liquid hydrogen (LH2)-cooled Nuclear Thermal Rocket (NTR) propulsion makes them attractive for upper stage applications for difficult robotic science missions to the outer planets. Besides high (I (sub sp)) and thrust, NTR engines can also be designed for "bimodal" operation allowing substantial amounts of electrical power (10's of kWe ) to be generated for onboard spacecraft systems and high data rate communications with Earth during the course of the mission. Two possible options for using the NTR are examined here. A high performance injection stage utilizing a single 15 klbf thrust engine can inject large payloads to the outer planets using a 20 t-class launch vehicle when operated in an "expendable mode". A smaller bimodal NTR stage generating approx. 1 klbf of thrust and 20 to 40 kWe for electric propulsion can deliver approx. 100 kg using lower cost launch vehicles. Additional information is contained in the original extended abstract.

Outer planet entry probe system study. Volume 2: Supporting technical studies

NASA Technical Reports Server (NTRS)

1972-01-01

The environment, science investigations, and general mission analysis considerations are given first. These data are followed by discussions of the studies pertaining to the planets Jupiter, Saturn, Uranus, and Neptune. Except for Neptune, each planet discussion is divided into two parts: (1) parametric activities and (2) probe definition for that planet, or the application of a given probe for that planet. The Neptune discussion is limited to parametrics in the area of science and mission analysis. Each of the probe system definitions consists of system and subsystem details including telecommunications, data handling, power pyrotechnics, attitude control, structures, propulsion, thermal control, and probe to spacecraft integration. The first configuration is discussed in detail and the subsequent configuration discussions are limited to the differences. Finally, the hardware availability to support a probe system and commonality of science, missions, and subsystems for use at the various planets are considered.

Outer planet entry probe system study. Volume 4: Common Saturn/Uranus probe studies

NASA Technical Reports Server (NTRS)

1973-01-01

Results are summarized of a common scientific probe study to explore the atmospheres of Saturn and Uranus. This was a three-month follow-on effort to the Outer Planet Entry Probe System study. The report presents: (1) a summary, conclusions and recommendations of this study, (2) parametric analysis conducted to support the two system definitions, (3) common Saturn/Uranus probe system definition using the Science Advisory Group's exploratory payload and, (4) common Saturn/Uranus probe system definition using an expanded science complement. Each of the probe system definitions consists of detailed discussions of the mission, science, system and subsystems including telecommunications, data handling, power, pyrotechnics, attitude control, structures, propulsion, thermal control and probe-to-spacecraft integration. References are made to the contents of the first three volumes where it is feasible to do so.

Dual-telescope multi-channel thermal-infrared radiometer for outer planet fly-by missions

NASA Astrophysics Data System (ADS)

Aslam, Shahid; Amato, Michael; Bowles, Neil; Calcutt, Simon; Hewagama, Tilak; Howard, Joseph; Howett, Carly; Hsieh, Wen-Ting; Hurford, Terry; Hurley, Jane; Irwin, Patrick; Jennings, Donald E.; Kessler, Ernst; Lakew, Brook; Loeffler, Mark; Mellon, Michael; Nicoletti, Anthony; Nixon, Conor A.; Putzig, Nathaniel; Quilligan, Gerard; Rathbun, Julie; Segura, Marcia; Spencer, John; Spitale, Joseph; West, Garrett

2016-11-01

The design of a versatile dual-telescope thermal-infrared radiometer spanning the spectral wavelength range 8-200 μm, in five spectral pass bands, for outer planet fly-by missions is described. The dual-telescope design switches between a narrow-field-of-view and a wide-field-of-view to provide optimal spatial resolution images within a range of spacecraft encounters to the target. The switchable dual-field-of-view system uses an optical configuration based on the axial rotation of a source-select mirror along the optical axis. The optical design, spectral performance, radiometric accuracy, and retrieval estimates of the instrument are discussed. This is followed by an assessment of the surface coverage performance at various spatial resolutions by using the planned NASA Europa Mission 13-F7 fly-by trajectories as a case study.

Dual-Telescope Multi-Channel Thermal-Infrared Radiometer for Outer Planet Fly-By Missions

NASA Technical Reports Server (NTRS)

Aslam, Shahid; Amato, Michael; Bowles, Neil; Calcutt, Simon; Hewagama, Tilak; Howard, Joseph; Howett, Carly; Hsieh, Wen-Ting; Hurford, Terry; Hurley, Jane;

Assessment of in-flight anomalies of long life outer plant mission

NASA Technical Reports Server (NTRS)

Hoffman, Alan R.; Green, Nelson W.; Garrett, Henry B.

2004-01-01

Thee unmanned planetary spacecraft to the outer planets have been controlled and operated successfully in space for an accumulated total of 66 years. The Voyager 1 and 2 spacecraft each have been in space for more than 26 years. The Galileo spacecraft was in space for 14 years, including eight years in orbit about Jupiter. During the flight operations for these missions, anomalies for the ground data system and the flight systems have been tracked using the anomaly reporting tool at the Jet Propulsion Laboratory. A total of 3300 incidents, surprises, and anomaly reports have been recorded in the database. This paper describes methods and results for classifying and identifying trends relative to ground system vs. flight system, software vs. hardware, and corrective actions. There are several lessons learned from these assessments that significantly benefit the design and planning for long life missions of the future. These include the necessity for having redundancy for successful operation of the spacecraft, awareness that anomaly reporting is dependent on mission activity not the age of the spacecraft, and the need for having a program to maintain and transfer operation knowledge and tools to replacement flight team members.

Feasibility study of low angle planetary entry. [probe design for Jovian entry

NASA Technical Reports Server (NTRS)

Defrees, R. E.

1975-01-01

The feasibility of a Jovian entry by a probe originally designed for Saturn and Uranus entries is examined. An entry probe is described which is capable of release near an outer planet's sphere of influence and descent to a predetermined target entry point in the planet's atmosphere. The probe is designed so as to survive the trapped particle radiation belts and an entry heating pulse. Data is gathered and relayed to an overflying spacecraft bus during descent. Probe variations for two similar missions are described. In the first flyby of Jupiter by a Pioneer spacecraft launched during the 1979 opportunity is examined parametrically. In the second mission an orbiter based on Pioneer and launched in 1980 is defined in specific terms. The differences rest in the science payloads and directly affected wiring and electronics packages.

Dust Hazard Management in the Outer Solar System

NASA Technical Reports Server (NTRS)

Seal, David A.

2012-01-01

Most robotic missions to the outer solar system must grapple with the hazards posed by the dusty rings of the gas giants. Early assessments of these hazards led simply to ring avoidance due to insufficient data and high uncertainties on the dust population present in such rings. Recent approaches, principal among them the Cassini dust hazard management strategy, provide useful results from detailed modeling of spacecraft vulnerabilities and dust hazard regions, which along with the range of mission trajectories are used to to assess the risks posed by each passage through a zone of potential hazard. This paper shows the general approach used to implement the analysis for Cassini, with recommendations for future outer planet missions.

Frequency standards requirements of the NASA deep space network to support outer planet missions

NASA Technical Reports Server (NTRS)

Fliegel, H. F.; Chao, C. C.

1974-01-01

Navigation of Mariner spacecraft to Jupiter and beyond will require greater accuracy of positional determination than heretofore obtained if the full experimental capabilities of this type of spacecraft are to be utilized. Advanced navigational techniques which will be available by 1977 include Very Long Baseline Interferometry (VLBI), three-way Doppler tracking (sometimes called quasi-VLBI), and two-way Doppler tracking. It is shown that VLBI and quasi-VLBI methods depend on the same basic concept, and that they impose nearly the same requirements on the stability of frequency standards at the tracking stations. It is also shown how a realistic modelling of spacecraft navigational errors prevents overspecifying the requirements to frequency stability.

Planetary quarantine

NASA Technical Reports Server (NTRS)

1977-01-01

Those areas of future missions which will be impacted by planetary quarantine (PQ) constraints were identified. The specific objectives for this reporting period were (1) to perform an analysis of the effects of PQ on an outer planet atmospheric probe, and (2) to prepare a quantitative illustration of spacecraft microbial reduction resulting from exposure to space environments. The Jupiter Orbiter Probe mission was used as a model for both of these efforts.

Voyager at Neptune: 1989

NASA Technical Reports Server (NTRS)

1989-01-01

The Voyager mission has taken advantage of a rare planetary alignment that occurs at intervals of about 175 years and affords an extraordinary opportunity: a grand tour by a single spacecraft of the outer planets Jupiter, Saturn, Uranus, and Neptune. Voyager 2 will fly past Nepture and its large moon Triton on August 24, 1989. The discovery of Neptune, along with its current history is discussed. The imaging challenges, tracking and data acquisition, and the Voyager spacecraft are explained. Data will be gathered on the ring arcs of Neptune, the atmosphere and surface of Neptune, Triton, and Nereid (the smaller moon).

Beyond Electric Propulsion: Non-Propulsive Benefits of Nuclear Power for the Exploration of the Outer Solar System

NASA Astrophysics Data System (ADS)

Zubrin, Robert M.

1994-07-01

In the past, most studies dealing with the benefits of space nuclear electric power systems for solar system exploration have focused on the potential of nuclear electric propulsion (NEP) to enhance missions by increasing delivered payload, decreasing LEO mass, or reducing trip time. While important, such mission enhancements have failed to go to the heart of the concerns of the scientific community supporting interplanetary exploration. To put the matter succinctly, scientists don't buy delivered payload - they buy data returned. With nuclear power we can increase both the quantity of data returned, by enormously increasing data communication rates, and the quality of data by enabling a host of active sensing techniques otherwise impossible. These non-propulsive mission enhancement capabilities of space nuclear power have been known in principle for many years, but they have not been adequately documented. As a result, support for the development of space nuclear power by the interplanetary exploration community has been much less forceful than it might otherwise be. In this paper we shall present mission designs that take full advantage of the potential mission enhancements offered by space nuclear power systems in the 10 to 100 kWe range, not just for propulsion, but to radically improve, enrich, and expand the science return itself. Missions considered include orbiter missions to each of the outer planets. It will be shown that be using hybrid trajectories combining chemical propulsion with NEP and (in certain cases) gravity assists, that it is possible, using a Titan IV-Centaur launch vehicle, for high-powered spacecraft to be placed in orbit around each of the outer planets with electric propulsion burn times of less than 4 years. Such hybrid trajectories therefore make the outer solar-system available to near-term nuclear electric power systems. Once in orbit, the spacecraft will utilize multi-kilowatt communication systems, similar to those now employed by the U.S. military, to increase data return far beyond that possible utilizing the 40 W rf traveling wave tube antennas that are the current NASA standard. This higher data rate will make possible very high resolution multi-spectral imaging (with high resolutions both spatially and spectrally), a form of science hitherto impossible in the outer solar system. Large numbers of such images could be returned, allowing the creation of motion pictures of atmospheric phenomenon on a small scale and greatly increasing the probability of capturing transient phenomena such as lighting or volcanic activity. The multi-kilowatt power sources on the spacecraft also enables active sensing, including radar, which could be used to do topographic and subsurface studies of clouded bodies such as Titan, ground penetrating sounding of Pluto, the major planet's moons, and planetoids, and topside sounding of the electrically conductive atmospheres of Jupiter, Saturn, Uranus and Neptune to produce profiles of fluid density, conductivity, and horizontal and vertical velocity as a function of depth and global location. Radio science investigations of planetary atmospheres and ring systems would be greatly enhanced by increased transmitter power. The scientific benefits of utilizing such techniques are discussed, and a comparison is made with the quantity and quality of science that a low-powered spacecraft employing RTGs could return. It is concluded that the non-propulsive benefits of nuclear power for spacecraft exploring the outer solar system are enormous, and taken together with the well documented mission enhancements enabled by electric propulsion fully justify the expenditures needed to bring a space qualified nuclear electric power source into being.

Laboratory evaluation and application of microwave absorption properties under simulated conditions for planetary atmospheres

NASA Technical Reports Server (NTRS)

Steffes, Paul G.

1988-01-01

Radio absorptivity data for planetary atmospheres obtained from spacecraft radio occultation experiments and earth-based radio astronomical observations can be used to infer abundances of microwave absorbing atmospheric constituents in those atmospheres, as long as reliable information regarding the microwave absorbing properties of potential constituents is available. The key activity for this grant year has continued to be laboratory measurements of the microwave and millimeter-wave properties of the simulated atmospheres of the outer planets and their satellites. A Fabry-Perot spectrometer system capable of operation from 32 to 41 GHz was developed. Initially this spectrometer was used to complete laboratory measurements of the 7.5 to 9.3 mm absorption spectrum of ammonia. Laboratory measurements were begun at wavelengths near 3.2 mm, where a large number of observations of the emission from the outer planets were made. A description of this system is presented.

Voyager's Grand Tour

NASA Technical Reports Server (NTRS)

Uri, Joihn J.

2017-01-01

In the early days of the Space Age, scientists realized that given the right planetary alignments it might be possible to use the gravity of one planet to change the trajectory of a spacecraft and send it on to another planet without expending any fuel. This slingshot or gravity assist trajectory principle was first tested by Mariner 10, which used the gravity of Venus to slingshot its way to Mercury in 1974. A very rare planetary alignment would occur in the late 1970's allowing a spacecraft to visit all the outer planets (Jupiter, Saturn, Uranus, Neptune and Pluto) using gravity assists at each planet to send it on to the next. This unique alignment would not occur again for another 175 years! The initial ambitious plan, called the Grand Tour, was to send two pairs of spacecraft, one pair to visit Jupiter, Saturn and Pluto, the other to fly by Jupiter, Uranus and Neptune. However, the original plan was scaled back in the budget conscious early 1970's to just two less capable spacecraft visiting only Jupiter and Saturn, and Titan, Saturn's largest moon Taking advantage of this alignment would be two Voyager spacecraft, both beginning their long journeys in 1977. Voyager 2 launched first, on August 20, followed by Voyager 1 on September 5. Both spacecraft would first fly by Jupiter and use that planet's massive gravity to bend their trajectories to then fly by Saturn. Voyager 1 would also be targeted to fly by Saturn's moon Titan, which was known to have a dense atmosphere, a trajectory that would preclude any future planetary flybys. But the option was kept open, if Voyager 1's Titan flyby was successful, to retarget Voyager 2 to send it on to Uranus and maybe even Neptune - assuming it would survive that long! Just 13 days after its launch, Voyager 1 scored the first of its many firsts: at a distance of 7.25 million miles, it turned its camera back toward Earth and snapped the first ever photograph of the Earth-Moon system in a single frame, giving a sneak preview of the discoveries that lay ahead.

Mariner 10 magnetic field observations of the Venus wake

NASA Technical Reports Server (NTRS)

Lepping, R. P.; Behannon, K. W.

1977-01-01

Magnetic field measurements made over a 21-hour interval during the Mariner 10 encounter with Venus were used to study the down-stream region of the solar wind-Venus interaction over a distance of approximately 100 R sub v. For most of the day before closest approach the spacecraft was located in a sheath-like region which was apparently bounded by planetary bow shock on the outer side and either a planetary wake boundary or transient boundary-like feature on the inner side. The spacecraft made multiple encounters with the wake-like boundary during the 21-hour interval with an increasing frequency as it approached the planet. Each pass into the wake boundary from the sheath region was consistently characterized by a slight decrease in magnetic field magnitude, a marked increase in the frequency and amplitude of field fluctuations, and a systematic clockwise rotation of the field direction when viewed from above the plane of the planet orbit.

Grooves and Kinks in the Rings

NASA Image and Video Library

2017-06-19

Many of the features seen in Saturn's rings are shaped by the planet's moons. This view from NASA's Cassini spacecraft shows two different effects of moons that cause waves in the A ring and kinks in a faint ringlet. The view captures the outer edge of the 200-mile-wide (320-kilometer-wide) Encke Gap, in the outer portion of Saturn's A ring. This is the same region features the large propeller called Earhart. Also visible here is one of several kinked and clumpy ringlets found within the gap. Kinks and clumps in the Encke ringlet move about, and even appear and disappear, in part due to the gravitational effects of Pan -- which orbits in the gap and whose gravitational influence holds it open. The A ring, which takes up most of the image on the left side, displays wave features caused by Pan, as well as the moons Pandora and Prometheus, which orbit a bit farther from Saturn on both sides of the planet's F ring. This view was taken in visible light with the Cassini spacecraft narrow-angle camera on March 22, 2017, and looks toward the sunlit side of the rings from about 22 degrees above the ring plane. The view was acquired at a distance of approximately 63,000 miles (101,000 kilometers) from Saturn and at a phase angle (the angle between the sun, the rings and the spacecraft) of 59 degrees. Image scale is 1,979 feet (603 meters) per pixel. https://photojournal.jpl.nasa.gov/catalog/PIA21333

Reliability considerations in long-life outer planet spacecraft system design

NASA Technical Reports Server (NTRS)

Casani, E. K.

1975-01-01

A Mariner Jupiter/Saturn mission has been planned for 1977. System reliability questions are discussed, taking into account the actual and design lifetime, causes of mission termination, in-flight failures and their consequences for the mission, and the use of redundancy to avoid failures. The design process employed optimizes the use of proven subsystem and system designs and then makes the necessary improvements to increase the lifetime as required.

Cassini Attitude and Articulation Control Subsystem Fault Protection Challenges During Saturn Proximal Orbits

NASA Technical Reports Server (NTRS)

Bates, David M.

2015-01-01

NASA's Cassini Spacecraft, launched on October 15th, 1997 arrived at Saturn on June 30th, 2004, is the largest and most ambitious interplanetary spacecraft in history. As the first spacecraft to achieve orbit at Saturn, Cassini has collected science data throughout its four-year prime mission (2004-08), and has since been approved for a first and second extended mission through 2017. As part of the final extended mission, Cassini will begin an aggressive and exciting campaign of high inclination low altitude flybys within the inner most rings of Saturn, skimming Saturn's outer atmosphere, until the spacecraft is finally disposed of via planned impact with the planet. This final campaign, known as the proximal orbits, presents unique fault protection related challenges, the details of which are discussed in this paper.

Properties of ultra low frequency upstream waves at Venus and Saturn: A comparison

NASA Technical Reports Server (NTRS)

Orlowski, D. S.; Russell, C. T.; Krauss-Varban, D.; Omidi, N.

1995-01-01

The upstream regions of all planets, except Pluto, have been investigated, using in situ spacecraft measurements and a variety of analysis techniques. The detailed studies at Earth indicate that these waves are generated locally in the magnetically connected solar wind by the interaction with ions backstreaming from the shock. However, since the properties of the solar wind vary with heliocentric distance and since properties of planetary shocks depend on plasma beta, interplanetary magnetic field (IMF) spiral angle and Mach number, the amount of heating, acceleration efficiencies, etc. significantly change with heliocentric distance. In turn the waves seen at each planet propagate not in the same but different (physical) propagation modes. In this paper we compare the ULF wave observations at an outer and an inner planet. We use the results of the ratio, quantites easily derivable with sufficient accuracy at each planet. We use the full electromagnetic dispersion relation for comparison with theoretical predictions.

Jupiter and the Voyager mission

USGS Publications Warehouse

Soderblom, L.; Spall, Henry

1980-01-01

In 1977, the United States launched two unmanned Voyager spacecraft that were to take part in an extensive reconnaissance of the outer planets over a 12-year period visiting the environs of Jupiter, Saturn, Uranus, and Neptune. Their first encounter was with the complex Jupiter planetary system 400 million miles away. Sweeping by Jupiter and its five moons in 1979, the two spacecraft have sent back to Earth an enormous amount of data that will prove to be vital in understanding our solar system. Voyager 1 is scheduled to fly past Saturn on November 13 of this year; Voyager 2, in August of the following year. 

The effects of external planets on inner systems: multiplicities, inclinations and pathways to eccentric warm Jupiters

NASA Astrophysics Data System (ADS)

Mustill, Alexander J.; Davies, Melvyn B.; Johansen, Anders

2017-07-01

We study how close-in systems such as those detected by Kepler are affected by the dynamics of bodies in the outer system. We consider two scenarios: outer systems of giant planets potentially unstable to planet-planet scattering and wide binaries that may be capable of driving Kozai or other secular variations of outer planets' eccentricities. Dynamical excitation of planets in the outer system reduces the multiplicity of Kepler-detectable planets in the inner system in ˜20-25 per cent of our systems. Accounting for the occurrence rates of wide-orbit planets and binary stars, ≈18 per cent of close-in systems could be destabilized by their outer companions in this way. This provides some contribution to the apparent excess of systems with a single transiting planet compared to multiple; however, it only contributes at most 25 per cent of the excess. The effects of the outer dynamics can generate systems similar to Kepler-56 (two coplanar planets significantly misaligned with the host star) and Kepler-108 (two significantly non-coplanar planets in a binary). We also identify three pathways to the formation of eccentric warm Jupiters resulting from the interaction between outer and inner systems: direct inelastic collision between an eccentric outer and an inner planet; secular eccentricity oscillations that may 'freeze out' when scattering resolves in the outer system; and scattering in the inner system followed by 'uplift', where inner planets are removed by interaction with the outer planets. In these scenarios, the formation of eccentric warm Jupiters is a signature of a past history of violent dynamics among massive planets beyond ˜1 au.

Research in space physics at the University of Iowa

NASA Technical Reports Server (NTRS)

Vanallen, J. A.

1976-01-01

Energetic particles in outer space and their relationship to electric, magnetic, and electromagnetic fields associated with the earth, sun, moon, and planets, and the interplanetary medium are investigated. Special attention was given to observations of earth and moon satellites and interplanetary spacecraft; phenomenological analysis and interpretation were emphasized. Data also cover ground based on radio astronomical and optical techniques and theoretical problems in plasma physics as revelant to solar planetary and interplanetary phenomena.

Outer satellite atmospheres: Their nature and planetary interactions. [atmospheric models for Amalthea, Ganymede, Callisto, and Titan are presented

NASA Technical Reports Server (NTRS)

Smyth, W. H.

1978-01-01

Results show that Amalthea is likely to form a tightly-bound partial toroidal-shaped hydrogen cloud about its planet, while Ganymede, Callisto and Titan may have rather large, complete and nearly symmetric toroidal-shaped clouds. The toroidal cloud for Amalthea compares favorably with spacecraft data of Pioneer 10 for a satellite escape flux of order 10 to the 11th power atoms/sq cm/sec. Model results for Ganymede, Callisto and Titan suggest that these extended hydrogen atmospheres are likely to be detected by the Voyager spacecrafts and that Titan's cloud might also be detected by the Pioneer 11 spacecraft. Ions created because of atoms lost through ionization processes from these four extended hydrogen atmospheres and from the sodium cloud of Io are discussed.

Cassini Operational Sun Sensor Risk Management During Proximal Orbit Saturn Ring Plane Crossings

NASA Technical Reports Server (NTRS)

Bates, David M.

2016-01-01

NASA's Cassini Spacecraft, launched on October 15th, 1997 which arrived at Saturn on June 30th, 2004, is the largest and most ambitious interplanetary spacecraft in history. As the first spacecraft to achieve orbit at Saturn, Cassini has collected science data throughout its four-year prime mission (2004–08), and has since been approved for a first and second extended mission through 2017. As part of the final extended missions, Cassini will begin an aggressive and exciting campaign of high inclination, low altitude flybys within the inner most rings of Saturn, skimming Saturn’s outer atmosphere, until the spacecraft is finally disposed of via planned impact with the planet. This final campaign, known as the proximal orbits, requires a strategy for managing the Sun Sensor Assembly (SSA) health, the details of which are presented in this paper.

Outer planet mission guidance and navigation for spinning spacecraft

NASA Technical Reports Server (NTRS)

Paul, C. K.; Russell, R. K.; Ellis, J.

1974-01-01

The orbit determination accuracies, maneuver results, and navigation system specification for spinning Pioneer planetary probe missions are analyzed to aid in determining the feasibility of deploying probes into the atmospheres of the outer planets. Radio-only navigation suffices for a direct Saturn mission and the Jupiter flyby of a Jupiter/Uranus mission. Saturn ephemeris errors (1000 km) plus rigid entry constraints at Uranus result in very high velocity requirements (140 m/sec) on the final legs of the Saturn/Uranus and Jupiter/Uranus missions if only Earth-based tracking is employed. The capabilities of a conceptual V-slit sensor are assessed to supplement radio tracking by star/satellite observations. By processing the optical measurements with a batch filter, entry conditions at Uranus can be controlled to acceptable mission-defined levels (+ or - 3 deg) and the Saturn-Uranus leg velocity requirements can be reduced by a factor of 6 (from 139 to 23 m/sec) if nominal specified accuracies of the sensor can be realized.

Revolutionary Concepts for Human Outer Planet Exploration (HOPE)

NASA Technical Reports Server (NTRS)

Troutman, Patrick A.; Bethke, Kristen; Stillwagen, Fred; Caldwell, Darrell L., Jr.; Manvi, Ram; Strickland, Chris; Krizan, Shawn A.

2003-01-01

This paper summarizes the content of a NASA-led study performed to identify revolutionary concepts and supporting technologies for Human Outer Planet Exploration (HOPE). Callisto, the fourth of Jupiter's Galilean moons, was chosen as the destination for the HOPE study. Assumptions for the Callisto mission include a launch year of 2045 or later, a spacecraft capable of transporting humans to and from Callisto in less than five years, and a requirement to support three humans on the surface for a minimum of 30 days. Analyses performed in support of HOPE include identification of precursor science and technology demonstration missions and development of vehicle concepts for transporting crew and supplies. A complete surface architecture was developed to provide the human crew with a power system, a propellant production plant, a surface habitat, and supporting robotic systems. An operational concept was defined that provides a surface layout for these architecture components, a list of surface tasks, a 30-day timeline, a daily schedule, and a plan for communication from the surface.

Heliopause Electrostatic Rapid Transit System (HERTS)

NASA Technical Reports Server (NTRS)

Wiegmann, Bruce M.

2015-01-01

A recent six month investigation focused on: "Determining the benefits of propelling a scientific spacecraft by an 'Electric Sail' propulsion system to the edge of our solar system (the Heliopause), a distance of 100 to 120 AU, in ten years or less" has recently been completed by the Advance Concepts Office at NASA's MSFC. The concept investigated has been named the Heliopause Electrostatic Rapid Transit System (HERTS) by the MSFC team. The HERTS is a revolutionary propellant-less propulsion concept that is ideal for deep space missions to the Outer Planets, Heliopause, and beyond. It is unique in that it uses momentum exchange from naturally occurring solar wind protons to propel a spacecraft within the heliosphere. The propulsion system consists of an array of electrically positively-biased wires that extend outward 20 km from a rotating (one revolution per hour) spacecraft. It was determined that the HERTS system can accelerate a spacecraft to velocities as much as two to three times that possible by any realistic extrapolation of current state-of-the-art propulsion technologies- including solar electric and solar sail propulsion systems. The data produced show that a scientific spacecraft could reach distances of 100AU in less than 10 years. Moreover, it can be reasonably expected that this system could be developed within a decade and provide meaningful Heliophysics Science and Outer Planetary Science returns in the 2025-2035 timeframe.

Microwave communications from outer planets - The Voyager Project

NASA Technical Reports Server (NTRS)

Brejcha, A. G.

1980-01-01

The paper summarizes the Voyager Project, the mission objectives, and the spacecraft communications system required to meet the mission objectives. The primary emphasis of the mission is on comparative studies of the Jupiter and Saturn systems in the areas of: (1) the environment, atmosphere and body characteristics of the planets, and one or more of the satellites, (2) the nature of the recently discovered Jovian ring and the rings of Saturn, and (3) the interplanetary medium at increasing distances from the sun. The complexities and problems, such as power consumption, weight, and antenna pointing constraints are presented, along with a detailed description of the radio frequency and S/X-band antenna subsystems.

Epimetheus Above the Rings

NASA Image and Video Library

2015-11-09

Although Epimetheus appears to be lurking above the rings here, it's actually just an illusion resulting from the viewing angle. In reality, Epimetheus and the rings both orbit in Saturn's equatorial plane. Inner moons and rings orbit very near the equatorial plane of each of the four giant planets in our solar system, but more distant moons can have orbits wildly out of the equatorial plane. It has been theorized that the highly inclined orbits of the outer, distant moons are remnants of the random directions from which they approached the planets they orbit. This view looks toward the unilluminated side of the rings from about -0.3 degrees below the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 26, 2015. The view was obtained at a distance of approximately 500,000 miles (800,000 kilometers) from Epimetheus and at a Sun-Epimetheus-spacecraft, or phase, angle of 62 degrees. Image scale is 3 miles (5 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA18342

Reacting to nuclear power systems in space: American public protests over outer planetary probes since the 1980s

NASA Astrophysics Data System (ADS)

Launius, Roger D.

2014-03-01

The United States has pioneered the use of nuclear power systems for outer planetary space probes since the 1970s. These systems have enabled the Viking landings to reach the surface of Mars and both Pioneers 10 and 11 and Voyagers 1 and 2 to travel to the limits of the solar system. Although the American public has long been concerned about safety of these systems, in the 1980s a reaction to nuclear accidents - especially the Soviet Cosmos 954 spacecraft destruction and the Three Mile Island nuclear power plant accidents - heightened awareness about the hazards of nuclear power and every spacecraft launch since that time has been contested by opponents of nuclear energy. This has led to a debate over the appropriateness of the use of nuclear power systems for spacecraft. It has also refocused attention on the need for strict systems of control and rigorous checks and balances to assure safety. This essay describes the history of space radioisotope power systems, the struggles to ensure safe operations, and the political confrontation over whether or not to allow the launch the Galileo and Cassini space probes to the outer planets. Effectively, these efforts have led to the successful flights of 12 deep space planetary probes, two-thirds of them operated since the accidents of Cosmos 954, Three Mile Island, and Chernobyl.

The Outer Planetary Mission Design Project

NASA Astrophysics Data System (ADS)

Benfield, Michael; Turner, M. W.

2010-10-01

With the recent focus from the planetary science community on the outer planets of the solar system, The University of Alabama in Huntsville Integrated Product Team program is embarking on a new challenge to develop an outer planetary mission for the academic year 2010-2011. Currently four bodies are of interest for this mission: Titan, Europa, Triton, and Enceledus, with one body being chosen by the instructors by the beginning of the fall semester. This project will use the 2010 Discovery Announcement of Opportunity as its Request for Proposal (RFP). All of the teams competing in this project will use the AO to respond with a proposal to the instructors for their proposed mission and spacecraft concept. The project employs the two-semester design sequence of the IPT program to provide a framework for the development of this mission. This sequence is divided into four phases. Phase 1 - Requirements Development - focuses on the development of both the scientific and engineering requirements of the mission. During this phase the teams work very closely with the PI organization, represented by the College of Charleston. Phase 2 - Team Formation and Architecture Development - concentrates on the assessment of the overall mission architecture from the launch vehicle to the ground operations of the proposed spacecraft. Phase 3 - System Definition - provides for spacecraft subsystem trade studies and further refinement of the specific spacecraft to meet the scientific requirements and objectives developed in Phase 1. Phase 4 - Design - is the phase where the engineers provide the spacecraft design that is required for the mission of interest. At the conclusion of Phases 2 and 4, an external review board evaluates the proposed designs and chooses one winner of the competition.

Launch Vehicle Directorate and Centaur Rocket Model

NASA Image and Video Library

1979-05-21

The National Aeronautics and Space Administration (NASA) Lewis Research Center’s Launch Vehicle Directorate in front of a full-scale model of the Centaur second-stage rocket. The photograph was taken to mark Centaur’s fiftieth launch. NASA Lewis managed the Centaur Program since 1962. At that time, the only prior launch attempt ended in failure. Lewis improved the spacecraft and tested it extensively throughout the early 1960s. In May 1966 an Atlas-Centaur sent the Surveyor spacecraft to the moon. It was the first successful soft landing on another planet. The Launch Vehicles Division was formed in 1969 to handle the increasing number of Centaur launches. The Lewis team became experts at integrating the payload with the Centaur and calculating proper trajectories for the missions. Centaur’s first 50 missions included Orbiting Astronomical Observatories, the Mariner 6 and 7 flybys of Mars, Mariner 9 which was the first spacecraft to orbit around another planet, the Pioneer 10 and 11 missions to the outer solar system, the Mariner 10 flyby of Venus and Mercury, the Viking 1 and 2 Mars landers, Voyagers 1 and 2 missions to Jupiter, Saturn, Uranus, and Neptune, and the Pioneer 12 and 13 flights to Venus.

On the writing of programming systems for spacecraft computers.

NASA Technical Reports Server (NTRS)

Mathur, F. P.; Rohr, J. A.

1972-01-01

Consideration of the systems designed to generate programs for the increasingly complex digital computers being used on board unmanned deep-space probes. Such programming systems must accommodate the special-purpose features incorporated in the hardware. The use of higher-level language facilities in the programming system can significantly simplify the task. Computers for Mariner and for the Outer Planets Grand Tour are briefly described, as well as their programming systems. Aspects of the higher level languages are considered.

Nuclear electric propulsion mission engineering study. Volume 2: Final report

NASA Technical Reports Server (NTRS)

1973-01-01

Results of a mission engineering analysis of nuclear-thermionic electric propulsion spacecraft for unmanned interplanetary and geocentric missions are summarized. Critical technologies associated with the development of nuclear electric propulsion (NEP) are assessed, along with the impact of its availability on future space programs. Outer planet and comet rendezvous mission analysis, NEP stage design for geocentric and interplanetary missions, NEP system development cost and unit costs, and technology requirements for NEP stage development are studied.

CHARACTERIZING THE ATMOSPHERES OF THE HR8799 PLANETS WITH HST/WFC3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rajan, Abhijith; Patience, Jennifer; Barman, Travis

We present results from a Hubble Space Telescope (HST) program characterizing the atmospheres of the outer two planets in the HR8799 system. The images were taken over 15 orbits in three near-infrared (near-IR) medium-band filters—F098M, F127M, and F139M—using the Wide Field Camera 3. One of the three filters is sensitive to a water absorption band inaccessible from ground-based observations, providing a unique probe of the thermal emission from the atmospheres of these young giant planets. The observations were taken at 30 different spacecraft rolls to enable angular differential imaging (ADI), and the full data set was analyzed with the Karhunen–Loévemore » Image Projection routine, an advanced image processing algorithm adapted to work with HST data. To achieve the required high contrast at subarcsecond resolution, we utilized the pointing accuracy of HST in combination with an improved pipeline designed to combine the dithered ADI data with an algorithm designed to both improve the image resolution and accurately measure the photometry. The results include F127M (J) detections of the outer planets, HR8799b and c, and the first detection of HR8799b in the water-band (F139M) filter. The F127M photometry for HR8799c agrees well with fitted atmospheric models, resolving the longstanding difficulty in consistently modeling the near-IR flux of the planet.« less

Electrically Isolating Subsystems in SOAC Technologies

NASA Technical Reports Server (NTRS)

Boyd, R. M.; Mojarradi, M. M.; Kuhn, W. B.; Shumaker, E. A.

2001-01-01

Integrated circuit fabrication technology has evolved to the point that it is possible to construct complete systems, including power, data processing, and communications, on a single chip. Such System-on-a-chip (SOAC) technologies can enable drastic reductions in spacecraft size and weight, lowering the cost of missions and presenting new mission opportunities. This paper overviews some key enabling technologies unique to the needs of spacecraft for outer-planet exploration and missions requiring extreme resistance to radiation such as Europa orbiters and Europa Landers. The work is being carried out by Kansas State University (KSU) under direction of the Center for Integrated Space Microsystems (CISM) at NASA's Jet Propulsion Laboratory. Additional information is contained in the original extended abstract.

Approach guidance for outer planet pioneer missions

NASA Technical Reports Server (NTRS)

Bejczy, A. K.

1975-01-01

Onboard optical approach guidance measurements for spin-stabilized Pioneer-type spacecraft are discussed. Approach guidance measurement accuracy requirements are outlined. The application concept and operation principle of the V-slit star tracker are discussed within the context of approach guidance measurements and measurables. It is shown that the accuracy of onboard optical approach guidance measurements is inherently coupled to the stability characteristics of the spacecraft spin axis. Geometrical and physical measurement parameters are presented for Pioneer entry probe missions to Uranus via Jupiter or Saturn flyby. The impact of these parameters on both sensor instrumentation and measurement system design is discussed. The need for sensing extended objects is shown. The feasibility of implementing an onboard approach guidance measurement system for Pioneer-type spacecraft is indicated. Two Pioneer 10 onboard measurement experiments performed in May-June 1974 are described.

Deep space telecommunications and the solar cycle: A reappraisal

NASA Technical Reports Server (NTRS)

Berman, A. L.

1978-01-01

Observations of density enhancement in the near corona at solar cycle (sunspot) maximum have rather uncritically been interpreted to apply equally well to the extended corona, thus generating concern about the quality of outer planet navigational data at solar cycle maximum. Spacecraft have been deployed almost continuously during the recently completed solar cycle 20, providing two powerful new coronal investigatory data sources: (1) in-situ spacecraft plasma measurements at approximately 1 AU, and (2) plasma effects on monochromatic spacecraft signals at all signal closest approach points. A comprehensive review of these (solar cycle 20) data lead to the somewhat surprising conclusions that for the region of interest of navigational data, the highest levels of charged particle corruption of navigational data can be expected to occur at solar cycle minimum, rather than solar cycle maximum, as previously believed.

Distant Saturn Sighting

NASA Image and Video Library

2002-11-01

Saturn appears serene and majestic in the first color composite made of images taken by NASA's Cassini spacecraft on its approach to the ringed planet, with arrival still 20 months away. The planet was 285 million kilometers (177 million miles) away from the spacecraft, nearly twice the distance between the Sun and Earth, when Cassini took images of it in various filters as an engineering test on Oct. 21, 2002. It is summer in Saturn's southern hemisphere. The Sun is a lofty 27 degrees below the equator and casts a semi-circular shadow of the planet on the rings. The shadow extends partway across the rings, leaving the outer A ring in sunlight. The last Saturn-bound spacecraft, Voyager 2, arrived in early northern spring. Many features seen in Voyager images -- spoke-like markings on the rings, clouds and eddies in the hazy atmosphere, ring-shepherding moons -- are not yet visible to Cassini. Titan, Saturn's largest moon, appears in the upper left. It is the only moon resolved from this distance. This composite uses a threefold enhancement in the brightness of Titan relative to the brightness of Saturn. Titan is a major attraction for scientists of the Cassini-Huygens mission. They will study its haze-enshrouded atmosphere and peer down, with special instrumentation, to its surface to look for evidence of organic processes similar to those that might have occurred on the early Earth, prior to the emergence of life. http://photojournal.jpl.nasa.gov/catalog/PIA02884

Outer Planet Science Missions enabled by Solar Power

NASA Astrophysics Data System (ADS)

Kaplan, M.; Klaus, K.; Smith, D. B.

2009-12-01

Our studies demonstrate that New Frontiers-class science missions to the Jupiter and Saturn systems are possible with commercial solar powered space craft. These spacecraft are flight proven with more than 60 years of in-space operation and are equipped with highly efficient solar arrays capable of up to 25kW in low earth orbit. Such a vehicle could generate nearly 1kW in the Jovian System. Our analysis shows substantially greater power at the end of mission with this solar array system than the system that is planned for use in the Europa Jupiter System Flagship mission study. In the next few years, a new solar array technology will be developed and demonstrated by DARPA that will provide even higher power. DARPA’s Fast Access Space Testbed (FAST) program objective is to develop a revolutionary approach to spacecraft high power generation. This high power generation Subsystem, when combined with electric propulsion, will form the technological basis for a light weight, high power, highly mobile spacecraft platform. The FAST program will demonstrate the implementation of solar concentrators and high flux solar cells in conjunction with high specific impulse electric propulsion, to produce a high performance, lightweight power and propulsion system. A basic FAST spacecraft design provides about 60 kW in LEO, which scales to > 2 kW at 5 AU, or a little less than 1 kW at 10 AU. In principle, higher power levels (120 kW or even 180kW at 1 AU) could be accommodated with this technology. We envision missions using this FAST array and NASA’s NEXT engines for solar electric propulsion (SEP) Jovian and Saturn system maneuvers. We envision FAST arrays to cost in the tens of millions, making this an affordable, plutonium-free way to do outer planets science. Continued funding will mean flight experiments conducted in the 2012 timeframe that could make this technology flight proven for the New Frontiers 4 opportunity.

Testing space weather connections in the solar system

NASA Astrophysics Data System (ADS)

Grison, B.; Souček, J.; Krupař, V.; Píša, D.; Santolík, O.; Taubenschuss, U.; Němec, F.

2017-09-01

This study aims at testing and validating tools for prediction of the impact of solar events in the vicinity of inner and outer solar system planets using in-situ spacecraft data (primarily MESSENGER, STEREO and ACE, but also VEX and Cassini), remote Jovian observations (Hubble telescope, Nançay decametric array), existing catalogues (HELCATS and Tao et al. (2005)) and the tested propagating models (the ICME radial propagation tool of the CDPP and the 1-D MHD code propagation model presented in Tao et al. (2005)).

Mapping photopolarimeter spectrometer instrument feasibility study for future planetary flight missions

NASA Technical Reports Server (NTRS)

1990-01-01

Evaluations are summarized directed towards defining optimal instrumentation for performing planetary polarization measurements from a spacecraft platform. An overview of the science rationale for polarimetric measurements is given to point out the importance of such measurements for future studies and exploration of the outer planets. The key instrument features required to perform the needed measurements are discussed and applied to the requirements for the Cassini mission to Saturn. The resultant conceptual design of a spectro-polarimeter photometer for Cassini is described in detail.

Pioneer 10/11 data analysis of the trapped radiation experiment

NASA Technical Reports Server (NTRS)

Fillius, W.

1982-01-01

The data handling operations and the database produced by the Trapped Radiation Experiment on the NASA Pioneer 10 and 11 spacecraft are outlined. In situ measurements of trapped radiation at both Jupiter and Saturn, the extension of cosmic ray observations to the outer heliosphere, the presence of Jovian electrons in interplanetary space, analyses of the interaction between planetary satellites and the trapped radiation that engulfs them, and further investigations of the radiation enviroments of both planets are reported.

Preentry communications study. Outer planets atmospheric entry probe

NASA Technical Reports Server (NTRS)

Hinrichs, C. A.

1976-01-01

A pre-entry communications study is presented for a relay link between a Jupiter entry probe and a spacecraft in hyperbolic orbit. Two generic communications links of interest are described: a pre-entry link to a spun spacecraft antenna, and a pre-entry link to a despun spacecraft antenna. The propagation environment of Jupiter is defined. Although this is one of the least well known features of Jupiter, enough information exists to reasonably establish bounds on the performance of a communications link. Within these bounds, optimal carrier frequencies are defined. The next step is to identify optimal relative geometries between the probe and the spacecraft. Optimal trajectories are established for both spun and despun spacecraft antennas. Given the optimal carrier frequencies, and the optimal trajectories, the data carrying capacities of the pre-entry links are defined. The impact of incorporating pre-entry communications into a basic post entry probe is then assessed. This assessment covers the disciplines of thermal control, power source, mass properties and design layout. A conceptual design is developed of an electronically despun antenna for use on a Pioneer class of spacecraft.

(abstract) Follow-on Missions for the Pluto Spacecraft

NASA Technical Reports Server (NTRS)

Weinstein, Stacy; Salvo, Chris; Stern, Alan

1994-01-01

The Pluto Fast Flyby mission development baseline consists of 2 identical spacecraft (120 - 165 kg) to be launched to Pluto/Charon in the late 1990s. These spacecraft are intended to fly by Pluto and Charon in order to perform various remote-sensing scientific investigations and have a mission development cost less than $400M (FY92$) through launch plus 30 days. The long-life (6 - 10 years) mission duration and lightweight design make the Pluto spacecraft a good candidate for a number of other flyby missions to objects in the outer Solar System, and some of these were investigated by JPL in cooperation with NASA Code SL's (Solar System Exploration) Outer Planets Science Working Group (OPSWG) in 1993. The JPL team looked at what it would mean to fly one of these missions (if a third spacecraft were available) in terms of flight time, spacecraft modifications, and science payload resources; the OPSWG recommended science investigation modifications for the different targets based on the available resources. The missions could, in many cases, utilize less capable launch vehicles, thereby reducing life-cycle cost of the mission. Examples of the sort of targets which were investigated and looked attractive in terms of flight time are: Uranus, Neptune, Uranus/Neptune dual-mission, Trojan asteroids (624 Hektor, 617 Patroclus, others), 5145 Pholus (the reddest object known in the solar system), and Kuiper Belt objects (i.e., 1992 QB1) . This paper will present the results of this investigation in terms of potential science return, performance, and the potential for life-cycle cost reductions through inheritance from Pluto Fast Flyby .

Maximizing the science return of interplanetary missions using nuclear electric power

NASA Astrophysics Data System (ADS)

Zubrin, Robert M.

1995-01-01

In the past, most studies dealing with the benefits of space nuclear electric power systems for solar system exploration have focused on the potential of nuclear electric propulsion (NEP) to enhance missions by increasing delivered payload, decreasing LEO mass, or reducing trip time. While important, such mission enhancements have failed to go to the heart of the concerns of the scientific community supporting interplanetary exploration. To put the matter succintly, scientists don't buy delivered payload—they buy data returned. With nuclear power we can increase both the quantity of data returned, by enormously increasing data communication rates, and the quality of data by enabling a host of active sensing techniques otherwise impossible. These non-propulsive mission enhancement capabilities of space nuclear power have been known in principle for many years, but they have not been adequately documented. As a result, support for the development of space nuclear power by the interplanetary exploration community has been much less forceful than it might otherwise be. In this paper we shall present mission designs that take full advantage of the potential mission enhancements offered by space nuclear power systems in the 15 to 30 kWe range, not just for propulsion, but to radically improve, enrich, and expand the science return itself. Missions considered include orbiter missions to each of the outer planets. It will be shown that by using hybrid trajectories combining chemical propulsion with NEP and (in certain cases) gravity assists, that it is possible, using Proton, Tatan III or Titan IV-Centaur launch vehicles, for high-powered spacecraft to be placed in orbit around each of the outer planets with electric propulsion burn times of less than 4 years. Such hybrid trajectories therefore make the outer solar-system available to near-term nuclear electric power systems. Once in orbit, the spacecraft will utilize multi-kilowatt communication systems, similar to those now employed by the U.S. military, to increse data return far beyond that possible utilizing the 40 W rf traveling wave tube antennas that are the current NASA stadard. This higher data rate will make possible very high resolution multi-space imaging (with high resolutions both spatially and spectrally), a form of science hitherto impossible in the outer solar system. Larger numbers of such images could be returned, allowing the creation of motion pictures of atmospheric phenomenon on a small scale and greatly increasing the probability of capturing transient phenomena such as lighting or volcanic activity. The multi-kilowatt power sources on the spaecraft also enables active sensing, including radar, which could be used to do topographic and subsurface studies of clouded bodies such as Titan, ground pentrating sounding of Pluto, the major planet's moons, and planetoids, and topside sounding of the electrically conductive atmospheres of Jupiter, Saturn, Uranus and Neptune to produce profiles of fluid density, conductivity, and horizontal and vertical velocity as a function of depth and global location. Radio science investigations of planetary atmospheres and ring systems would be greatly enhanced by increased transmitter power. The scientific benefits of utilizing such techniques are discussed, and a comparison is made with the quantity and quality of science that a low-powered spacecraft employing RTGs could return. It is concluded that the non-propulsive benefits of nuclear power for spacecraft exploring the outer solar system are enormous, and taken together with the well documented mission enhancements enabled by electric propulsion fully justify the expanditures needed to bring a space qualified nuclear electric power source into being.

Performance comparison of earth and space storable bipropellant systems in interplanetary missions

NASA Technical Reports Server (NTRS)

Meissinger, H. F.

1978-01-01

The paper evaluates and compares the performance of earth-storable and space-storable liquid bipropellant propulsion systems in high-energy planetary mission applications, including specifically Saturn and Mercury orbiters, as well as asteroid and comet rendezvous missions. The discussion covers a brief review of the status of space-storable propulsion technology, along with an illustrative propulsion module design for a three-axis stabilized outer planet and cometary mission spacecraft of the Mariner class. The results take revised Shuttle/Upper Stage performance projections into account. It is shown that in some of the missions the performance improvement achievable in the ballistic transfer mode with space-storable spacecraft propulsion can provide a possible alternative to the use of solar-electric propulsion.

Ion Thruster Power Levels Extended by a Factor of 10

NASA Technical Reports Server (NTRS)

Patterson, Michael J.

2004-01-01

In response to two NASA Office of Space Science initiatives, the NASA Glenn Research Center is now developing a 7-kW-class xenon ion thruster system for near-term solar-powered spacecraft and a 25-kW ion engine for nuclear-electric spacecraft. The 7-kW ion thruster and power processor can be throttled down to 1 kW and are applicable to 25-kW flagship missions to the outer planets, asteroids, and comets. This propulsion system was scaled up from the 2.5-kW ion thruster and power processor that was developed successfully by Glenn, Boeing, the Jet Propulsion Laboratory (JPL), and Spectrum Astro for the Deep Space 1 spacecraft. The 7-kW ion thruster system is being developed under NASA's Evolutionary Xenon Thruster (NEXT) project, which includes partners from JPL, Aerojet, Boeing, the University of Michigan, and Colorado State University.

Advances in space power research and technology at the National Aeronautics and Space Administration

NASA Technical Reports Server (NTRS)

Mullin, J. P.; Randolph, L. P.; Hudson, W. R.; Ambrus, J. H.

1981-01-01

Progress and plans in various areas of the NASA Space Power Program are discussed. Solar cell research is narrowed to GaAs, multibandgap, and thin Si cells for arrays in planar and concentrator configurations, with further work to increase cell efficiency, radiation hardness, develop flexible encapsulants, and reduce cost. Electrochemical research is concentrating on increasing energy and power density, cycle and wet stand life, reliability and cost reduction of batteries. Further development of the Ni-H2 battery and O2-H2 fuel cell to multihundred kW with a 5 year life and 30,000 cycles is noted. Basic research is ongoing for alkali metal anodes for high energy density secondary cells. Nuclear thermoelectric propulsion is being developed for outer planets exploration propulsion systems, using Si-Ge generators, and studies with rare earth chalcogenides and sulfides are mentioned. Power Systems Management seeks to harmonize increasing power supply levels with inner and outer spacecraft environments, circuits, demands, and automatic monitoring. Concomitant development of bipolar transistors, an infrared rectenna, spacecraft charging measurement, and larger heat pipe transport capacity are noted.

Outer planet entry probe system study. Volume 1: Summary

NASA Technical Reports Server (NTRS)

1972-01-01

General mission considerations and science prospectus, which are of a general nature that applies to several or all planetary applications, are presented. Five probe systems are defined: nominal Jupiter probe system, and Jupiter probe-dedicated alternative probe system, Jupiter spacecraft radiation-compatible alternative probe system, Saturn probe system, and Saturn probe applicability for Uranus. Parametric analysis is summarized for mission analysis of a general nature, and then for specific missions to Jupiter, Saturn, Uranus, and Neptune. The program is also discussed from the hardware availability viewpoint and the aspect of commonality.

Nuclear electric propulsion mission engineering study. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1973-01-01

Results of a mission engineering analysis of nuclear-thermionic electric propulsion spacecraft for unmanned interplanetary and geocentric missions are summarized. Critical technologies associated with the development of nuclear electric propulsion (NEP) are assessed. Outer planet and comet rendezvous mission analysis, NEP stage design for geocentric and interplanetary missions, NEP system development cost and unit costs, and technology requirements for NEP stage development are studied. The NEP stage design provides both inherent reliability and high payload mass capability. The NEP stage and payload integration was found to be compatible with the space shuttle.

Reusable Hybrid Propellant Modules for Outer-Space Transport

NASA Technical Reports Server (NTRS)

Mazanek, Daniel D.; Mankins, John C.

2005-01-01

A report summarizes the concept of reusable hybrid propellant modules (HPMs), which would be used in outer space for long-term cryogenic storage of liquefied spacecraft-propellant gases, including for example, oxygen and hydrogen for combustion-based chemical rocket engines and xenon for electric thrusters. The HPM concept would provide the fundamental building block for an efficient, reusable in-space transportation system for both crewed and uncrewed missions. Each HPM would be equipped to implement an advanced zero-boil-off method of managing cryogenic fluids, and would include a fluid-transfer interface comprising standardized fittings that would be compatible with fittings on all supply facilities and on spacecraft to be supplied. The HPM, combined with a chemical or electric orbital transfer spacecraft, would provide an integrated propulsion system. HPMs would supply chemical propellant for time-critical transfers such as crewed missions, and utilize the more efficient electric-propulsion transfer vehicles to transport filled HPMs to the destinations and to return empty HPMs back to near-Earth orbits or other intermediate locations for replenishment and reuse. The HPM prepositioned using electric propulsion would provide the chemical propellant for the crew s return trip in a much more efficient manner than a chemical-only approach. The propellants to fill the HPMs would be delivered from the Earth or other initial supply locations to the intermediate locations by use of automated, compatible spacecraft designed specifically for that purpose. Additionally, multiple HPMs could be aggregated and positioned in orbits and on planets, moons, and asteroids to supply fluids to orbiting and interplanetary spacecraft.

Dance of the Planets

ERIC Educational Resources Information Center

Riddle, Bob

2005-01-01

As students continue their monthly plotting of the planets along the ecliptic they should start to notice differences between inner and outer planet orbital motions, and their relative position or separation from the Sun. Both inner and outer planets have direct eastward motion, as well as retrograde motion. Inner planets Mercury and Venus,…

The carbon budget in the outer solar nebula.

PubMed

Simonelli, D P; Pollack, J B; McKay, C P; Reynolds, R T; Summers, A L

1989-01-01

Detailed models of the internal structures of Pluto and Charon, assuming rock and water ice as the only constituents, indicate that the mean silicate mass fraction of this two-body system is on the order of 0.7; thus the Pluto/Charon system is significantly "rockier" than the satellites of the giant planets (silicate mass fraction approximately 0.55). This compositional contrast reflects different formation mechanisms: it is likely that Pluto and Charon formed directly from the solar nebula, while the circumplanetary nebulae that produced the giant planet satellites were derived from envelopes that surrounded the forming giant planets (envelopes in which icy planetesimals dissolved more readily than rocky planetesimals). Simple cosmic abundance calculations, and the assumption that the Pluto/Charon system formed directly from solar nebula condensates, strongly suggest that the majority of the carbon in the outer solar nebula was in the form of carbon monoxide; these results are consistent with (1) inheritance from the dense molecular clouds in the interstellar medium (where CH4/CO < 10(-2) in the gas phase) and/or (2) of the Lewis and Prinn kinetic inhibition model of solar nebula chemistry. Theoretical predictions of the C/H enhancements in the atmospheres of the giant planets, when compared to the actual observed enhancements, suggest that 10%, or slightly more, of the carbon in the outer solar nebula was in the form of condensed materials (although the amount of condensed C may have dropped slightly with increasing heliocentric distance). Strict compositional limits computed for the Pluto/Charon system using the densities of CH4 and CO ices indicate that these pure ices are at best minor components in the interiors of these bodies, and imply that CH4 and CO ices were not the dominant C-bearing solids in the outer nebula. Clathrate-hydrates could not have appropriated enough CH4 or CO to be the major form of condensed carbon, although such clathrates may be necessary to explain the presence of methane on Pluto after its formation from a CO-rich nebula. Laboratory studies of carbonaceous chondrites, and spacecraft observations of Comet Halley, strongly suggest that of the remaining possibilities, organic material, rather than elemental carbon, is the most likely candidate for the dominant C-bearing solid in the outer solar nebula. We conclude that the majority of the carbon in the outer solar nebula was in gaseous CO; 10% to a few tens of percent of the C was in condensed organic materials; and at least a trace amount of carbon was in methane gas.

In Space Nuclear Power as an Enabling Technology for Deep Space Exploration

NASA Technical Reports Server (NTRS)

Sackheim, Robert L.; Houts, Michael

2000-01-01

Deep Space Exploration missions, both for scientific and Human Exploration and Development (HEDS), appear to be as weight limited today as they would have been 35 years ago. Right behind the weight constraints is the nearly equally important mission limitation of cost. Launch vehicles, upper stages and in-space propulsion systems also cost about the same today with the same efficiency as they have had for many years (excluding impact of inflation). Both these dual mission constraints combine to force either very expensive, mega systems missions or very light weight, but high risk/low margin planetary spacecraft designs, such as the recent unsuccessful attempts for an extremely low cost mission to Mars during the 1998-99 opportunity (i.e., Mars Climate Orbiter and the Mars Polar Lander). When one considers spacecraft missions to the outer heliopause or even the outer planets, the enormous weight and cost constraints will impose even more daunting concerns for mission cost, risk and the ability to establish adequate mission margins for success. This paper will discuss the benefits of using a safe in-space nuclear reactor as the basis for providing both sufficient electric power and high performance space propulsion that will greatly reduce mission risk and significantly increase weight (IMLEO) and cost margins. Weight and cost margins are increased by enabling much higher payload fractions and redundant design features for a given launch vehicle (higher payload fraction of IMLEO). The paper will also discuss and summarize the recent advances in nuclear reactor technology and safety of modern reactor designs and operating practice and experience, as well as advances in reactor coupled power generation and high performance nuclear thermal and electric propulsion technologies. It will be shown that these nuclear power and propulsion technologies are major enabling capabilities for higher reliability, higher margin and lower cost deep space missions design to reliably reach the outer planets for scientific exploration.

Voyager First Science Meeting

NASA Image and Video Library

2016-10-27

This archival image was released as part of a gallery comparing JPL's past and present, commemorating the 80th anniversary of NASA's Jet Propulsion Laboratory on Oct. 31, 2016. In December 1972, the science steering group for a mission then-known as Mariner Jupiter Saturn 1977 -- later renamed Voyager -- met for the first time at NASA's Jet Propulsion Laboratory in Pasadena, Calif. They are gathered on the steps in front of the administration building (180). The mission was so named because it was planning to send Mariner-class spacecraft to Jupiter and Saturn. It was renamed Voyager a few months before the launch of the twin spacecraft in August and September 1977. This photo shows principal investigators and team leaders for the science experiments and several others from the project and NASA who attended the first meeting. In the first row: Radio Science Subsystem Team Leader Von Eshleman, Project Scientist Edward Stone, Project Manager Harris (Bud) Schurmeier, Mission Analysis and Engineering Manager Ralph Miles, Magnetometer Principal Investigator Norman Ness, NASA Planetary Program Office Deputy Director Ichtiaque Rasool, Robert Soberman (who was proposed to be the principal investigator of the Particulate Matter Investigation, which was not confirmed) and an unidentified member of the NASA Office of Space Science. In the second row: Infrared Interferometer Spectrometer Principal Investigator Rudolf Hanel, Planetary Radio Astronomy Principal Investigator James Warwick, Ultraviolet and Spectrometer Principal Investigator A. Lyle Broadfoot. In the third row: Low-Energy Charged Particles Principal Investigator Stamatios (Tom) Krimigis, Cosmic Ray Subsystem Principal Investigator Rochus (Robbie) Vogt, NASA Outer Planets Missions Program Manager Warren Keller, Imaging Science Subsystem Team Leader Bradford Smith and Photopolarimeter Principal Investigator Charles Lillie. In the fourth row: Plasma Investigation Principal Investigator Herbert Bridge, Spacecraft Systems Manager Raymond Heacock, NASA Outer Planets Missions Program Scientist Milton (Mike) Mitz and Science Manager James Long. http://photojournal.jpl.nasa.gov/catalog/PIA21122

The applicability of frame imaging from a spinning spacecraft. Volume 1: Summary report

NASA Technical Reports Server (NTRS)

Botticelli, R. A.; Johnson, R. O.; Wallmark, G. N.

1973-01-01

A detailed study was made of frame-type imaging systems for use on board a spin stabilized spacecraft for outer planets applications. All types of frame imagers capable of performing this mission were considered, regardless of the current state of the art. Detailed sensor models of these systems were developed at the component level and used in the subsequent analyses. An overall assessment was then made of the various systems based upon results of a worst-case performance analysis, foreseeable technology problems, and the relative reliability and radiation tolerance of the systems. Special attention was directed at restraints imposed by image motion and the limited data transmission and storage capability of the spacecraft. Based upon this overall assessment, the most promising systems were selected and then examined in detail for a specified Jupiter orbiter mission. The relative merits of each selected system were then analyzed, and the system design characteristics were demonstrated using preliminary configurations, block diagrams, and tables of estimated weights, volumes and power consumption.

Open-systems architecture of a standardized command interface chip-set for switching and control of a spacecraft power bus

NASA Technical Reports Server (NTRS)

Ruiz, Ian B.; Burke, Gary R.; Lung, Gerald; Whitaker, William D.; Nowicki, Robert M.

2004-01-01

The Jet Propulsion Laboratory (JPL) has developed a command interface chip-set that primarily consists of two mixed-signal ASICs'; the Command Interface ASIC (CIA) and Analog Interface ASIC (AIA). The Open-systems architecture employed during the design of this chip-set enables its use as both an intelligent gateway between the system's flight computer and the control, actuation, and activation of the spacecraft's loads, valves, and pyrotechnics respectfully as well as the regulator of the spacecraft power bus. Furthermore, the architecture is highly adaptable and employed fault-tolerant design methods enabling a host of other mission uses including reliable remote data collection. The objective of this design is to both provide a needed flight component that meets the stringent environmental requirements of current deep space missions and to add a new element to a growing library that can be used as a standard building block for future missions to the outer planets.

Voyager flight engineering - Preparing for Uranus

NASA Technical Reports Server (NTRS)

Mclaughlin, W. I.; Wolff, D. M.

1985-01-01

Two Voyager spacecraft are currently engaged in exploration of the outer solar system with Voyager 2 scheduled to conduct the first close-up investigation of the planet Uranus during the period November 4, 1985 through March 3, 1986. Flight engineering for the Voyager project has the objectives of delivering a functioning spacecraft containing observing sequences to the right places at the right times. Due to the changing environment as the mission has progressed outward from Jupiter to Saturn to Uranus (and on to Neptune), this engineering task has included the development of significant new capabilities. The paper utilizes the case-study method to examine some new spacecraft capabilities in three subsystems: data, attitude and articulation control, and power. The implementation of a new navigational data-type, delta DOR, is also reviewed. An overview is given of the Voyager sequencing process for the cruise and encounter phases with a case study focusing on late updating of part of the near encounter sequence. The prospective mission to Neptune is previewed.

Grand Tour outer planet missions definition phase. Part 1: Quantitative imaging of the outer planets and their satellites

NASA Technical Reports Server (NTRS)

Belton, M. J. S.; Aksnes, K.; Davies, M. E.; Hartmann, W. K.; Millis, R. L.; Owen, T. C.; Reilly, T. H.; Sagan, C.; Suomi, V. E.; Collins, S. A., Jr.

1972-01-01

A recommended imaging system is outlined for use aboard the Outer Planet Grand Tour Explorer. The system features the high angular resolution capacity necessary to accommodate large encounter distances, and to satisfy the demand for a reasonable amount of time coverage. Specifications for all components within the system are provided in detail.

Atmospheric entry probes for outer planet exploration. Outer planet entry probe technical summary

NASA Technical Reports Server (NTRS)

1974-01-01

The use of unmanned space probes for investigating the conditions existing on and around the outer planets of the solar system is discussed. The subjects included in the report are: (1) the design of a common entry probe for outer planet missions, (2) the significant trades related to the development of a common probe design, (3) the impact of bus selection on probe design, (4) the impact of probe requirements on bus modifications, and (5) the key technology elements recommended for advanced development. Drawings and illustrations of typical probes are included to show the components and systems used in the space probes.

Outer-planet scattering can gently tilt an inner planetary system

NASA Astrophysics Data System (ADS)

Gratia, Pierre; Fabrycky, Daniel

2017-01-01

Chaotic dynamics are expected during and after planet formation, and a leading mechanism to explain large eccentricities of gas giant exoplanets is planet-planet gravitational scattering. The same scattering has been invoked to explain misalignments of planetary orbital planes with respect to their host star's spin. However, an observational puzzle is presented by Kepler-56, which has two inner planets (b and c) that are nearly coplanar with each other, yet are more than 45° inclined to their star's equator. Thus, the spin-orbit misalignment might be primordial. Instead, we further develop the hypothesis in the discovery paper, that planets on wider orbits generated misalignment through scattering, and as a result gently torqued the inner planets away from the equator plane of the star. We integrated the equations of motion for Kepler-56 b and c along with an unstable outer system initialized with either two or three Jupiter-mass planets. We address here whether the violent scattering that generates large mutual inclinations can leave the inner system intact, tilting it gently. In almost all of the cases initially with two outer planets, either the inner planets remain nearly coplanar with each other in the star's equator plane, or they are scattered violently to high mutual inclination and high spin-orbit misalignment. On the contrary, of the systems with three unstable outer planets, a spin-orbit misalignment large enough to explain the observations is generated 28 per cent of the time for coplanar inner planets, which is consistent with the observed frequency of this phenomenon reported so far. We conclude that multiple-planet scattering in the outer parts of the system may account for this new population of coplanar planets hosted by oblique stars.

Mission Design for the Innovative Interstellar Explorer Vision Mission

NASA Technical Reports Server (NTRS)

Fiehler, Douglas I.; McNutt, Ralph L.

2005-01-01

The Innovative Interstellar Explorer, studied under a NASA Vision Mission grant, examined sending a probe to a heliospheric distance of 200 Astronomical Units (AU) in a "reasonable" amount of time. Previous studies looked at the use of a near-Sun propulsive maneuver, solar sails, and fission reactor powered electric propulsion systems for propulsion. The Innovative Interstellar Explorer's mission design used a combination of a high-energy launch using current launch technology, a Jupiter gravity assist, and electric propulsion powered by advanced radioisotope power systems to reach 200 AU. Many direct and gravity assist trajectories at several power levels were considered in the development of the baseline trajectory, including single and double gravity assists utilizing the outer planets (Jupiter, Saturn, Uranus, and Neptune). A detailed spacecraft design study was completed followed by trajectory analyses to examine the performance of the spacecraft design options.

Application of hybrid propulsion systems to planetary missions

NASA Technical Reports Server (NTRS)

Don, J. P.; Phen, R. L.

1971-01-01

The feasibility and application of hybrid rocket propulsion to outer-planet orbiter missions is assessed in this study and guidelines regarding future development are provided. A Jupiter Orbiter Mission was selected for evaluation because it is the earliest planetary mission which may require advanced chemical propulsion. Mission and spacecraft characteristics which affect the selection and design of propulsion subsystems are presented. Alternative propulsion subsystems, including space-storable bipropellant liquids, a solid/monopropellant vernier, and a hybrid, are compared on the basis of performance, reliability, and cost. Cost-effectiveness comparisons are made for a range of assumptions including variation in (1) the level of need for spacecraft performance (determined in part by launch vehicle injected mass capability), and (2) achievable reliability at corresponding costs. The results indicated that the hybrid and space-storable bipropellant mechanizations are competitive.

Evaluation of fluid behavior in spinning toroidal tanks

NASA Technical Reports Server (NTRS)

Anderson, J. E.; Fester, D. A.; Dugan, D. W.

1976-01-01

An experimental study was conducted to evaluate propellant behavior in spinning toroidal tanks that could be used in a retro-propulsion system of an advanced outer-planet Pioneer orbiter. Information on propellant slosh and settling and on ullage orientation and stability was obtained. The effects of axial acceleration, spin rate, spin rate change, and spacecraft wobble, both singly and in combination, were evaluated using a 1/8-scale transparent tank in one-g and low-g environments. Liquid loadings ranged from 5% to 96% full. The impact of a surface tension acquisition device was assessed. Testing simulated the behavior of F2/N2H4 and N2O4/MMH propellants. Results are presented which indicate no major fluid behavior problems would be encountered with any of the four propellants in the toroidal tanks of a spin-stabilized orbiter spacecraft.

Fluid interaction with spinning toroidal tanks

NASA Technical Reports Server (NTRS)

Fester, D. A.; Anderson, J. E.

1977-01-01

An experimental study was conducted to evaluate propellant behavior in spinning torroidal tanks that could be used in a retropropulsion system of an advanced outer-planet Pioneer orbiter. Information on propellant slosh and settling and on ullage orientation and stability was obtained. The effects of axial acceleration, spin rate, spin-rate change, and spacecraft wobble, both singly and in combination, were evaluated using a one-eighth scale transparent tank in one-g and low-g environments. Liquid loadings ranged from 5% to 96% full. The impact of a surface tension acquisition device was assessed by comparison with bare-tank results. The testing simulated the behavior of the fluorine/hydrazine and nitrogen textroxide/monomethylhydrazine propellants. Results are presented that indicate that no major fluid behavior problems would be encountered with any of the four propellants in the toroidal tanks of a spin-stabilized orbiter spacecraft.

From Galileo's telescope to the Galileo spacecraft: our changing views of the Jupiter system

NASA Astrophysics Data System (ADS)

Lopes, R. M.

2008-12-01

In four centuries, we have gone from the discovery of the four large moons of Jupiter - Io, Europa, Ganymede, and Callisto - to important discoveries about these four very different worlds. Galileo's telescopic discovery was a major turning point in the understanding of science. His observations of the moons' motion around Jupiter challenged the notion of an Earth-centric Universe. A few months later, Galileo discovered the phases of Venus, which had been predicted by the heliocentric model of the Solar System. Galileo also observed the rings of Saturn (which he mistook for planets) and sunspots, and was the first person to report mountains and craters on the Moon, whose existence he deduced from the patterns of light and shadow on the Moon's surface, concluding that the surface was topographically rough. Centuries later, the Galileo spacecraft's discoveries challenged our understanding of outer planet satellites. Results included the discovery of an icy ocean underneath Europa's surface, the possibility of life on Europa, the widespread volcanism on Io, and the detection of a magnetic field around Ganymede. All four of these satellites revealed how the major geologic processes - volcanism, tectonism, impact cratering and erosion - operate in these different bodies, from the total lack of impact craters on Io to the heavily cratered, ancient surface of Callisto. The Galileo spacecraft's journey also took it to Venus and the Moon, making important scientific observations about these bodies. The spacecraft discovered the first moon orbiting around an asteroid which, had Galileo the man observed, would have been another major blow for the geocentric model of our Solar System.

Thermomechanical piston pump development

NASA Technical Reports Server (NTRS)

Sabelman, E. E.

1971-01-01

A thermally powered reciprocating pump has been devised to replace or augment an electric pump for the transport of temperature-control fluid on the Thermoelectric Outer Planet Spacecraft (TOPS). The thermally powered pump operates cyclically by extracting heat energy from the fluid by means of a vapor-pressure expansion system and by using the heat to perform the mechanical work of pumping. A feasibility test unit has been constructed to provide an output of 7 cu in during a 10- to 100-second cycle. It operates with a fluid input temperature of 200 to 300 F and a heat sink temperature of 0 to 30 F.

Research in space physics at the University of Iowa. [astronomical observatories, spaceborne astronomy, satellite observation

NASA Technical Reports Server (NTRS)

Vanallen, J. A.

1974-01-01

Various research projects in space physics are summarized. Emphasis is placed on: (1) the study of energetic particles in outer space and their relationships to electric, magnetic, and electromagnetic fields associated with the earth, the sun, the moon, the planets, and interplanetary medium; (2) observational work on satellites of the earth and the moon, and planetary and interplanetary spacecraft; (3) phenomenological analysis and interpretation; (4) observational work by ground based radio-astronomical and optical techniques; and (5) theoretical problems in plasma physics. Specific fields of current investigations are summarized.

Orbital alignment of circumbinary planets that form in misaligned circumbinary discs: the case of Kepler-413b

NASA Astrophysics Data System (ADS)

Pierens, A.; Nelson, R. P.

2018-06-01

Although most of the circumbinary planets detected by the Kepler spacecraft are on orbits that are closely aligned with the binary orbital plane, the systems Kepler-413 and Kepler-453 exhibit small misalignments of ˜2.5°. One possibility is that these planets formed in a circumbinary disc whose midplane was inclined relative to the binary orbital plane. Such a configuration is expected to lead to a warped and twisted disc, and our aim is to examine the inclination evolution of planets embedded in these discs. We employed 3D hydrodynamical simulations that examine the disc response to the presence of a modestly inclined binary with parameters that match the Kepler-413 system, as a function of disc parameters and binary inclinations. The discs all develop slowly varying warps, and generally display very small amounts of twist. Very slow solid body precession occurs because a large outer disc radius is adopted. Simulations of planets embedded in these discs resulted in the planet aligning with the binary orbit plane for disc masses close to the minimum mass solar nebular, such that nodal precession of the planet was controlled by the binary. For higher disc masses, the planet maintains near coplanarity with the local disc midplane. Our results suggest that circumbinary planets born in tilted circumbinary discs should align with the binary orbit plane as the disc ages and loses mass, even if the circumbinary disc remains misaligned from the binary orbit. This result has important implications for understanding the origins of the known circumbinary planets.

Balloon/Parachute to Orbiter Communications Using a Dipole Antenna

NASA Technical Reports Server (NTRS)

Kantak, Anil V.; Danos, Monika J.

2001-01-01

Currently, quite a few missions are being studied to send satellites to the outer and inner planets and their moons of the solar system; a large percentage of these missions will have a landed element. NASA's Origins program, Solar System Exploration, Program and Sun Earth Connection (SEC) program, etc., will have a variety of spacecrafts to various solar system planets and their moons to sample and analyze the related atmospheres as well as the soil once the lander lands on the body. These sampling missions may involve a tender element sampling the atmosphere by performing experiments while descending into the atmosphere or a rover collecting samples to return to Earth or a station for experimentation on the planet surface. In either of these cases, the pertinent data generated will have to be sent to the Earth through a communication link. Communications with the Tender during the Entry, Decent and Landing (EDL) phases of a mission is of paramount importance. This article explores a particular method of passing through the atmosphere while communicating with the ground station (DSN station) before landing an instrument package (the lander) on the surface of the planet or moon of interest.

Joint NASA-ESA Outer Planet Mission study overview

NASA Astrophysics Data System (ADS)

Lebreton, J.-P.; Niebur, C.; Cutts, J.; Falkner, P.; Greeley, R.; Lunine, J.; Blanc, M.; Coustenis, A.; Pappalardo, R.; Matson, D.; Clark, K.; Reh, K.; Stankov, A.; Erd, C.; Beauchamp, P.

2009-04-01

In 2008, ESA and NASA performed joint studies of two highly capable scientific missions to the outer planets: the Europa Jupiter System Mission (EJSM) and the Titan Saturn System Mission (TSSM). Joint Science Definition Teams (JSDTs) were formed with U.S. and European membership to guide study activities that were conducted collaboratively by engineering teams working on both sides of the Atlantic. EJSM comprises the Jupiter Europa Orbiter (JEO) that would be provided by NASA and the Jupiter Ganymede Orbiter (JGO) that would be provided by ESA. Both spacecraft would be launched independently in 2020, and arrive 6 years later for a 3-4 year mission within the Jupiter System. Both orbiters would explore Jupiter's system on trajectories that include flybys of Io (JEO only), Europa (JEO only), Ganymede and Callisto. The operation of JEO would culminate in orbit around Europa while that of JGO would culminate in orbit around Ganymede. Synergistic and coordinated observations would be planned. The Titan Saturn System Mission (TSSM) comprises a Titan Orbiter provided by NASA that would carry two Titan in situ elements provided by ESA: the montgolfière and the lake lander. The mission would launch in 2020 and arrive 9 years later for a 4-year duration in the Saturn system. Following delivery of the ESA in situ elements to Titan, the Titan Orbiter would explore the Saturn system via a 2-year tour that includes Enceladus and Titan flybys. The montgolfière would last at least 6-12 months at Titan and the lake lander 8-10 hours. Following the Saturn system tour, the Titan Orbiter would culminate in a ~2-year orbit around Titan. Synergistic and coordinated observations would be planned between the orbiter and in situ elements. The ESA contribution to this joint endeavor will be implemented as the first Cosmic Vision Large-class (L1) mission; the NASA contribution will be implemented as the Outer Planet Flagship Mission. The contribution to each mission is being reviewed and evaluated by each agency between November 2008 and January 2009, and a joint decision as to which destination has been selected is expected to be announced in February 2009. The ESA Cosmic Vision selection process includes two additional competitive steps (that include two competing astronomy missions) before its contribution to the selected Outer Planet Mission is confirmed in 2012. NASA expects to proceed with the initial implementation of the mission in FY2009, while full implementation will start in FY2013, in line with ESA Cosmic Vision schedule. Should ESA select an astronomy mission instead, NASA would proceed in 2013 with the implementation of a NASA-only mission concept. This presentation will provide an overview of the selected Outer Planet Mission and outline the next steps towards its implementation.

Activities conducted during the definition phase of the outer planets missions program

NASA Technical Reports Server (NTRS)

1972-01-01

The activities are described of the Meteoroid Science Team for the definition phase of the outer planet missions. Studies reported include: (1) combined zodiacal experiment for the Grand Tour Missions of the outer planets, (2) optical transmission of a honeycomb panel and its effectiveness as a particle impact surface, (3) element identification data from the combined zodiacal OPGT experiment and (4) development of lightweight thermally stable mirrors.

A SUPER-EARTH-SIZED PLANET ORBITING IN OR NEAR THE HABITABLE ZONE AROUND A SUN-LIKE STAR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barclay, Thomas; Burke, Christopher J.; Howell, Steve B.

We present the discovery of a super-Earth-sized planet in or near the habitable zone of a Sun-like star. The host is Kepler-69, a 13.7 mag G4V-type star. We detect two periodic sets of transit signals in the 3-year flux time series of Kepler-69, obtained with the Kepler spacecraft. Using the very high precision Kepler photometry, and follow-up observations, our confidence that these signals represent planetary transits is >99.3%. The inner planet, Kepler-69b, has a radius of 2.24{sup +0.44}{sub -0.29} R{sub Circled-Plus} and orbits the host star every 13.7 days. The outer planet, Kepler-69c, is a super-Earth-sized object with a radiusmore » of 1.7{sup +0.34}{sub -0.23} R{sub Circled-Plus} and an orbital period of 242.5 days. Assuming an Earth-like Bond albedo, Kepler-69c has an equilibrium temperature of 299 {+-} 19 K, which places the planet close to the habitable zone around the host star. This is the smallest planet found by Kepler to be orbiting in or near the habitable zone of a Sun-like star and represents an important step on the path to finding the first true Earth analog.« less

Return to Mercury: a global perspective on MESSENGER's first Mercury flyby.

PubMed

Solomon, Sean C; McNutt, Ralph L; Watters, Thomas R; Lawrence, David J; Feldman, William C; Head, James W; Krimigis, Stamatios M; Murchie, Scott L; Phillips, Roger J; Slavin, James A; Zuber, Maria T

2008-07-04

In January 2008, the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft became the first probe to fly past the planet Mercury in 33 years. The encounter revealed that Mercury is a dynamic system; its liquid iron-rich outer core is coupled through a dominantly dipolar magnetic field to the surface, exosphere, and magnetosphere, all of which interact with the solar wind. MESSENGER images confirm that lobate scarps are the dominant tectonic landform and record global contraction associated with cooling of the planet. The history of contraction can be related to the history of volcanism and cratering, and the total contractional strain is at least one-third greater than inferred from Mariner 10 images. On the basis of measurements of thermal neutrons made during the flyby, the average abundance of iron in Mercury's surface material is less than 6% by weight.

Images From Comet’s Mars Flyby On This Week @NASA - October 24, 2014

NASA Image and Video Library

2014-10-24

Several Mars-based NASA spacecraft had prime viewing positions for comet Siding Spring’s October 19 close flyby of the Red Planet. Early images included a composite photo from NASA’s Hubble Space Telescope that combined shots of Mars, the comet, and a star background to illustrate Siding Spring’s distance from Mars at closest approach. Also, images from the Mars Reconnaissance Orbiter’s HiRISE camera, which represent the highest-resolution views ever acquired of a comet that came from the Oort Cloud, at the outer fringe of the solar system. The comet flyby – only about 87,000 miles from Mars – was much closer than any other known comet flyby of a planet. Also, Partial solar eclipse, Space station spacewalk, Preparing to release Dragon, Cygnus launch update, Welding begins on SLS, Astronaut class visits Glenn and more!

Preentry communication design elements for outer planets atmospheric entry probe

NASA Technical Reports Server (NTRS)

1976-01-01

Four related tasks are discussed for data transmission from a probe prior to entering the atmosphere of Jupiter to an orbiting spacecraft in a trajectory past the planet: (1) link analysis and design; (2) system conceptual design; (3) Doppler measurement analysis; and (4) an electronically despun antenna. For tasks 1, 3, and 4, an analytical approach was developed and combined with computational capability available to produce quantitative results corresponding to requirements and constraints given by NASA, ARC. One constraint having a major impact on the numerical results of the link analysis was the assumption of a nonsteerable antenna on a spinning orbiter. Other constraints included the interplanetary trajectory and the approach trajectory. Because the Jupiter Orbiter Probe (JOP) program is currently in a state of evolution, all requirements and constraints applied during this study are subject to change. However, the relationships of parameters as developed will remain valid and will aid in planning Jupiter missions.

Short Shadow

NASA Image and Video Library

2017-05-15

The projection of Saturn's shadow on the rings grows shorter as Saturn's season advances toward northern summer, thanks to the planet's permanent tilt as it orbits the sun. This will continue until Saturn's solstice in May 2017. At that point in time, the shadow will extend only as far as the innermost A ring, leaving the middle and outer A ring completely free of the planet's shadow. Over the course of NASA's Cassini mission, the shadow of Saturn first lengthened steadily until equinox in August 2009. Since then, the shadow has been shrinking. This view looks toward the sunlit side of the rings from about 10 degrees above the ring plane. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Feb. 3, 2017. The view was acquired at a distance of approximately 760,000 miles (1.2 million kilometers) from Saturn. Image scale is 46 miles (73 kilometers) per pixel. https://photojournal.jpl.nasa.gov/catalog/PIA21328

Planetary Protection for future missions to Europa and other icy moons: the more things change...

NASA Astrophysics Data System (ADS)

Conley, C. A.; Race, M.

2007-12-01

NASA maintains a planetary protection policy regarding contamination of extraterrestrial bodies by terrestrial microorganisms and organic compounds, and sets limits intended to minimize or prevent contamination resulting from spaceflight missions. Europa continues to be a high priority target for astrobiological investigations, and other icy moons of the outer planets are becoming increasingly interesting as data are returned from current missions. In 2000, a study was released by the NRC that provided recommendations on preventing the forward contamination of Europa. This study addressed a number of issues, including cleaning and sterilization requirements, the applicability of protocols derived from Viking and other missions to Mars, and the need to supplement spore based culture methods in assessing spacecraft bioload. The committee also identified a number of future studies that would improve knowledge of Europa and better define issues related to forward contamination of that body. The standard recommended by the 2000 study and adopted by NASA uses a probabilistic approach, such that spacecraft sent to Europa must demonstrate a probability less than 10-4 per mission of contaminating an europan ocean with one viable terrestrial organism. A number of factors enter into the equation for calculating this probability, including at least bioload at launch, probability of survival during flight, probability of reaching the surface of Europa, and probability of reaching an europan ocean. Recently, the NASA Planetary Protection Subcommittee of the NASA Advisory Council has recommended that the probabilistic approach recommended for Europa be applied to all outer planet icy moons, until another NRC study can be convened to reevaluate the issues in light of recent data. This presentation will discuss the status of current and anticipated planetary protection considerations for missions to Europa and other icy moons.

Constraints on Mercury's Core-Mantle Boundary Region

NASA Astrophysics Data System (ADS)

Hauck, S. A., II; Chabot, N. L.; Sun, P.; Jing, Z.; Johnson, C. L.; Margot, J. L.; Padovan, S.; Peale, S. J.; Phillips, R. J.; Solomon, S. C.

2014-12-01

Understanding the boundary between a planet's metallic core and silicate mantle is important for constraining processes that dominate on either side of this boundary. Geophysical measurements of the planet Mercury by the MESSENGER spacecraft have provided evidence of a core larger than earlier, less-constrained estimates. Further, these results, taken in concert with measurements of the elemental composition of the surface by MESSENGER, have led to the suggestion that the uppermost layer of the outer core may be highly enriched in sulfur, and the top of the core may consist of a solid sulfide layer. The low iron and relatively large sulfur contents of the surface indicate highly reducing conditions during planet formation, placing constraints on the potential composition of Mercury's core. Recent metal-silicate partitioning experiments have developed new limits on the amount of sulfur and silicon that may partition into the core as a function of sulfur abundance at the surface. Models for the planet's internal structure constrained by the current best estimates of the bulk density, normalized polar moment of inertia, and fraction of the polar moment of inertia of the solid layer that extends from the surface to the top of the liquid outer core provide an important view of the layering and bulk composition of Mercury. By combining the results of these internal structure models with the experimental relationship between core and mantle composition we place new limits on core composition and structure. Further, imposing measured compositional constraints on the miscibility of iron-sulfur-silicon alloys yields important limits on the presence or absence of an immiscible sulfur-rich liquid layer or a solid sulfide layer at the top of the core.

Life Beyond the Planet of Origin and Implications for the Search for Life on Mars

NASA Technical Reports Server (NTRS)

Mancinelli, Rocco L.

2015-01-01

Outer space is vast, cold, devoid of matter, radiation filled with essentially no gravity. These factors present an environmental challenge for any form of life. Earth's biosphere has evolved for more than 3 billion years shielded from the hostile environment of outer space by the protective blanket of the atmosphere and magnetosphere. Space is a nutritional wasteland with no liquid water and readily available organic carbon. Moving beyond a life's planet of origin requires a means for transport, the ability to withstand transport, and the ability to colonize, thrive and ultimately evolve in the new environment. Can life survive beyond its home planet? The key to answering this question is to identify organisms that first have the ability to withstand space radiation, space vacuum desiccation and time in transit, and second the ability to grow in an alien environment. Within the last 60 years space technology allowed us to transport life beyond Earth's protective shield so we may study, in situ, their responses to selected conditions of space. To date a variety of microbes ranging from viruses, to Bacteria, to Archaea, to Eukarya have been tested in the space environment. Most died instantly, but not all. These studies revealed that ultraviolet radiation is the near-term lethal agent, while hard radiation is the long-term lethal agent when the organism is shielded from ultraviolet radiation. In fact, bacterial spores, halophilic cyanobacteria and Archaea as well as some lichens survive very well if protected from ultraviolet radiation [1]. Some microbes, then, may be able to survive the trip in outer space to Mars on a spacecraft or in a meteorite. Once on Mars can a terrestrial microbe survive? Although the conditions on Mars are not as harsh as those in space, they are not hospitable for a terrestrial microbe. Studies, however, have shown that certain microbes that can survive in space for several years may also be able to survive on Mars if protected from ultraviolet radiation [1]. Laboratory simulation experiments using a mock-up of the Phoenix lander have shown that microbes transported to the surface of Mars on a spacecraft come off the spacecraft and mix into the Martian regolith [2]. Additionally, studies simulating Martian dust storms demonstrate that microbes can survive in the Martian wind blown dust and be scattered across the Martian surface away from the spacecraft. Would these microbes that may survive on Mars metabolize and propagate? Growth requires liquid water, a carbon source and an energy source. Survival on Mars also requires protection from ultraviolet radiation. In the cold, dry environment of Mars the probability of microbial metabolism and growth at or just beneath the surface is extremely low. Although the probability is low, Mars may be contaminated with potentially live terrestrial organisms. In light of that statistic we must be extremely diligent and cautious in our search for Martian life. If we are not cautious we may find life on Mars and it may be a contaminant from Earth.

Blue Marble: Remote Characterization of Habitable Planets

NASA Technical Reports Server (NTRS)

Woolf, Neville; Lewis, Brian; Chartres, James; Genova, Anthony

2009-01-01

The study of the nature and distribution of habitable environments beyond the Solar System is a key area for Astrobiology research. At the present time, our Earth is the only habitable planet that can be characterized in the same way that we might characterize planets beyond the Solar System. Due to limitations in our current and near-future technology, it is likely that extra-solar planets will be observed as single-pixel objects. To understand this data, we must develop skills in analyzing and interpreting the radiation obtained from a single pixel. These skills must include the study of the time variation of the radiation, and the range of its photometric, spectroscopic and polarimetric properties. In addition, to understand whether we are properly analyzing the single pixel data, we need to compare it with a ground truth of modest resolution images in key spectral bands. This paper discusses the concept for a mission called Blue Marble that would obtain data of the Earth using a combination of spectropolarimetry, spectrophotometry, and selected band imaging. To obtain imagery of the proper resolution, it is desirable to place the Blue Marble spacecraft no closer than the outer region of cis-lunar space. This paper explores a conceptual mission design that takes advantage of low-cost launchers, bus designs and mission elements to provide a cost effective observing platform located at one of the stable Earth-moon Lagrangian points (L4, L5). The mission design allows for the development and use of novel technologies, such as a spinning moon sensor for attitude control, and leverages lessons-learned from previous low-cost spacecraft such as Lunar Prospector to yield a low-risk mission concept.

Aerocapture Technology Development Needs for Outer Planet Exploration

NASA Technical Reports Server (NTRS)

Wercinski, Paul; Munk, Michelle; Powell, Richard; Hall, Jeff; Graves, Claude; Partridge, Harry (Technical Monitor)

2002-01-01

The purpose of this white paper is to identify aerocapture technology and system level development needs to enable NASA future mission planning to support Outer Planet Exploration. Aerocapture is a flight maneuver that takes place at very high speeds within a planet's atmosphere that provides a change in velocity using aerodynamic forces (in contrast to propulsive thrust) for orbit insertion. Aerocapture is very much a system level technology where individual disciplines such as system analysis and integrated vehicle design, aerodynamics, aerothermal environments, thermal protection systems (TPS), guidance, navigation and control (GN&C) instrumentation need to be integrated and optimized to meet mission specific requirements. This paper identifies on-going activities, their relevance and potential benefit to outer planet aerocapture that include New Millennium ST7 Aerocapture concept definition study, Mars Exploration Program aeroassist project level support, and FY01 Aeroassist In-Space Guideline tasks. The challenges of performing aerocapture for outer planet missions such as Titan Explorer or Neptune Orbiter require investments to advance the technology readiness of the aerocapture technology disciplines for the unique application of outer planet aerocapture. This white paper will identify critical technology gaps (with emphasis on aeroshell concepts) and strategies for advancement.

The Moon: Keystone to Understanding Planetary Geological Processes and History

NASA Technical Reports Server (NTRS)

2002-01-01

Extensive and intensive exploration of the Earth's Moon by astronauts and an international array of automated spacecraft has provided an unequaled data set that has provided deep insight into geology, geochemistry, mineralogy, petrology, chronology, geophysics and internal structure. This level of insight is unequaled except for Earth. Analysis of these data sets over the last 35 years has proven fundamental to understanding planetary surface processes and evolution, and is essential to linking surface processes with internal and thermal evolution. Much of the understanding that we presently have of other terrestrial planets and outer planet satellites derives from the foundation of these data. On the basis of these data, the Moon is a laboratory for understanding of planetary processes and a keystone for providing evolutionary perspective. Important comparative planetology issues being addressed by lunar studies include impact cratering, magmatic activity and tectonism. Future planetary exploration plans should keep in mind the importance of further lunar exploration in continuing to build solid underpinnings in this keystone to planetary evolution. Examples of these insights and applications to other planets are cited.

Gravity Field and Internal Structure of Mercury from MESSENGER

NASA Technical Reports Server (NTRS)

Smith, David E.; Zuber, Maria T.; Phillips, Roger J.; Solomon, Sean C.; Hauck, Steven A., II; Lemoine, Frank G.; Mazarico, Erwan; Neumann, Gregory A.; Peale, Stanton J.; Margot, Jean-Luc;

Gravity field and internal structure of Mercury from MESSENGER.

PubMed

Smith, David E; Zuber, Maria T; Phillips, Roger J; Solomon, Sean C; Hauck, Steven A; Lemoine, Frank G; Mazarico, Erwan; Neumann, Gregory A; Peale, Stanton J; Margot, Jean-Luc; Johnson, Catherine L; Torrence, Mark H; Perry, Mark E; Rowlands, David D; Goossens, Sander; Head, James W; Taylor, Anthony H

2012-04-13

Radio tracking of the MESSENGER spacecraft has provided a model of Mercury's gravity field. In the northern hemisphere, several large gravity anomalies, including candidate mass concentrations (mascons), exceed 100 milli-Galileos (mgal). Mercury's northern hemisphere crust is thicker at low latitudes and thinner in the polar region and shows evidence for thinning beneath some impact basins. The low-degree gravity field, combined with planetary spin parameters, yields the moment of inertia C/MR(2) = 0.353 ± 0.017, where M and R are Mercury's mass and radius, and a ratio of the moment of inertia of Mercury's solid outer shell to that of the planet of C(m)/C = 0.452 ± 0.035. A model for Mercury's radial density distribution consistent with these results includes a solid silicate crust and mantle overlying a solid iron-sulfide layer and an iron-rich liquid outer core and perhaps a solid inner core.

New Understanding of Mercury's Magnetosphere from MESSENGER'S First Flyby

NASA Technical Reports Server (NTRS)

Slavin, James A.; Acuna, Mario H.; Anderson, Brian J.; Baker, Daniel N.; Benna, Mehdi; Gloeckler, George; Gold, Robert E.; Ho, George C.; Killen, M.; Korth, Haje;

Design consideration for a nuclear electric propulsion system

NASA Technical Reports Server (NTRS)

Phillips, W. M.; Pawlik, E. V.

1978-01-01

A study is currently underway to design a nuclear electric propulsion vehicle capable of performing detailed exploration of the outer-planets. Primary emphasis is on the power subsystem. Secondary emphasis includes integration into a spacecraft, and integration with the thrust subsystem and science package or payload. The results of several design iterations indicate an all-heat-pipe system offers greater reliability, elimination of many technology development areas and a specific weight of under 20 kg/kWe at the 400 kWe power level. The system is compatible with a single Shuttle launch and provides greater safety than could be obtained with designs using pumped liquid metal cooling. Two configurations, one with the reactor and power conversion forward on the spacecraft with the ion engines aft and the other with reactor, power conversion and ion engines aft were selected as dual baseline designs based on minimum weight, minimum required technology development and maximum growth potential and flexibility.

Using Drained Spacecraft Propellant Tanks for Habitation

NASA Technical Reports Server (NTRS)

Thomas, Andrew S. W.

2009-01-01

A document proposes that future spacecraft for planetary and space exploration be designed to enable reuse of drained propellant tanks for occupancy by humans. This proposal would enable utilization of volume and mass that would otherwise be unavailable and, in some cases, discarded. Such utilization could enable reductions in cost, initial launch mass, and number of launches needed to build up a habitable outpost in orbit about, or on the surface of, a planet or moon. According to the proposal, the large propellant tanks of a spacecraft would be configured to enable crews to gain access to their interiors. The spacecraft would incorporate hatchways, between a tank and the crew volume, that would remain sealed while the tank contained propellant and could be opened after the tank was purged by venting to outer space and then refilled with air. The interior of the tank would be pre-fitted with some habitation fixtures that were compatible with the propellant environment. Electrical feed-throughs, used originally for gauging propellants, could be reused to supply electric power to equipment installed in the newly occupied space. After a small amount of work, the tank would be ready for long-term use as a habitation module.

Environmental Impact Specification for Direct Space Weathering of Kuiper Belt and Oort Cloud Objects

NASA Technical Reports Server (NTRS)

Cooper, John F.

2010-01-01

The Direct Space Weathering Project of NASA's Outer Planets Research Program addresses specification of the plasma and energetic particle environments for irradiation and surface chemical processing of icy bodies in the outer solar system and the local interstellar medium. Knowledge of the radiation environments is being expanded by ongoing penetration of the twin Voyager spacecraft into the heliosheath boundary region of the outer heliosphere and expected emergence within the next decade into the very local interstellar medium. The Voyager measurements are being supplemented by remote sensing from Earth orbit of energetic neutral atom emission from this boundary region by NASA's Interstellar Boundary Explorer (IBEX). Although the Voyagers long ago passed the region of the Classical Kuiper Belt, the New Horizons spacecraft will encounter Pluto in 2015 and thereafter explore one or more KBOs, meanwhile providing updated measurements of the heliospheric radiation environment in this region. Modeling of ion transport within the heliosphere allows specification of time-integrated irradiation effects while the combination of Voyager and IBEX data supports projection of the in-situ measurements into interstellar space beyond the heliosheath. Transformation of model ion flux distributions into surface sputtering and volume ionization profiles provides a multi-layer perspective for space weathering impact on the affected icy bodies and may account for some aspects of color and compositional diversity. Other important related factors may include surface erosion and gardening by meteoritic impacts and surface renewal by cryovolcanism. Chemical products of space weathering may contribute to energy resources for the latter.

Dust Impacts In the Outer Solar System Detected by Voyagers 1 and 2

NASA Astrophysics Data System (ADS)

Gurnett, D. A.; Persoon, A. M.; Granroth, L. J.; Kurth, W. S.

2011-12-01

The plasma wave instruments (PWS) on the Voyager 1 and 2 spacecraft, which are currently at about 119 and 97 AU, have been consistently detecting a low rate of dust impacts as the spacecraft proceed outward from the Sun into interstellar space. Because of the high radial velocity of the spacecraft, ~ 17 and 15 km/sec, when a dust particle strikes the spacecraft it is almost instantly vaporized and ionized, thereby producing a rapidly expanding cloud of plasma that causes a voltage pulse in the PWS electric antenna. The voltage pulse has a very rapid rise time of about 10 μs and is an easily identifiable waveform in the wideband electric field data. Due to a failure in the Voyager 2 waveform receiver no impact data are available from Voyager 2 beyond about 60 AU. However, the Voyager 1 waveform receiver is still working. Because of the very high data rates involved, 115.2 kb/s, antenna voltage waveforms can only be recorded for less than a minute per week, so the effective observing time is very small. Nonetheless, once the regions around the outer planets are excluded, a consistent background impact rate of a few impacts per hour is observed by both spacecraft. The impact rate appears to be increasing slightly with increasing radial distance, from about 3 ± 1 impacts per hour at 30 AU, to 6 ± 4 impacts per hour at 110 AU. If the impact cross-section of the spacecraft is assumed to be determined by the spacecraft high gain antenna, which has an area of 10.75 square meters, the corresponding particle flux varies from about 0.75 x 10-14 m-2 s-1 at 30 AU, to about 1.5 x 10-14 m-2 s-1 at 110 AU. Although we have no reliable method of estimating the size or origin of the particles, we note that this flux is consistent with the flux of submicron particles (10-15 to 10-9 g) arriving from interstellar space as detected by the Ulysses spacecraft at radial distances inside of 5 AU. Therefore, we believe that the particles are probably of interstellar origin.

Emerging communications technologies for outer-planet exploration

NASA Technical Reports Server (NTRS)

Stelzried, C.; Lesh, J.

2001-01-01

Communication over long free space distances is extremely difficult due to the inverse squared propagation losses associated with link distance. That makes communications particularly difficult from outer planet destinations.

A nuclear electric propulsion vehicle for planetary exploration

NASA Technical Reports Server (NTRS)

Pawlik, E. V.; Phillips, W. M.

1976-01-01

A study is currently underway at JPL to design a nuclear electric-propulsion vehicle capable of performing detailed exploration of the outer planets. Evaluation of the design indicates that it is also applicable to orbit raising. Primary emphasis is on the power subsystem. Work on the design of the power system, the mission rationale, and preliminary spacecraft design are summarized. A propulsion system at a 400-kWe power level with a specific weight goal of no more than 25-kg/kW was selected for this study. The results indicate that this goal can be realized along with compatibility with the shuttle launch-vehicle constraints.

Planet-Planet Scattering in Planetesimal Disks. II. Predictions for Outer Extrasolar Planetary Systems

NASA Astrophysics Data System (ADS)

Raymond, Sean N.; Armitage, Philip J.; Gorelick, Noel

2010-03-01

We develop an idealized dynamical model to predict the typical properties of outer extrasolar planetary systems, at radii comparable to the Jupiter-to-Neptune region of the solar system. The model is based upon the hypothesis that dynamical evolution in outer planetary systems is controlled by a combination of planet-planet scattering and planetary interactions with an exterior disk of small bodies ("planetesimals"). Our results are based on 5000 long duration N-body simulations that follow the evolution of three planets from a few to 10 AU, together with a planetesimal disk containing 50 M ⊕ from 10 to 20 AU. For large planet masses (M >~ M Sat), the model recovers the observed eccentricity distribution of extrasolar planets. For lower-mass planets, the range of outcomes in models with disks is far greater than that which is seen in isolated planet-planet scattering. Common outcomes include strong scattering among massive planets, sudden jumps in eccentricity due to resonance crossings driven by divergent migration, and re-circularization of scattered low-mass planets in the outer disk. We present the distributions of the eccentricity and inclination that result, and discuss how they vary with planet mass and initial system architecture. In agreement with other studies, we find that the currently observed eccentricity distribution (derived primarily from planets at a <~ 3 AU) is consistent with isolated planet-planet scattering. We explain the observed mass dependence—which is in the opposite sense from that predicted by the simplest scattering models—as a consequence of strong correlations between planet masses in the same system. At somewhat larger radii, initial planetary mass correlations and disk effects can yield similar modest changes to the eccentricity distribution. Nonetheless, strong damping of eccentricity for low-mass planets at large radii appears to be a secure signature of the dynamical influence of disks. Radial velocity measurements capable of detecting planets with K ≈ 5 m s-1 and periods in excess of 10 years will provide constraints on this regime. Finally, we present an analysis of the predicted separation of planets in two-planet systems, and of the population of planets in mean-motion resonances (MMRs). We show that, if there are systems with ~ Jupiter-mass planets that avoid close encounters, the planetesimal disk acts as a damping mechanism and populates MMRs at a very high rate (50%-80%). In many cases, resonant chains (in particular the 4:2:1 Laplace resonance) are set up among all three planets. We expect such resonant chains to be common among massive planets in outer planetary systems.

The Dynamics of Tightly-packed Planetary Systems in the Presence of an Outer Planet: Case Studies Using Kepler-11 and Kepler-90

NASA Astrophysics Data System (ADS)

Granados Contreras, A. P.; Boley, A. C.

2018-03-01

We explore the effects of an undetected outer giant planet on the dynamics, observability, and stability of Systems with Tightly-packed Inner Planets (STIPs). We use direct numerical simulations along with secular theory and synthetic secular frequency spectra to analyze how analogues of Kepler-11 and Kepler-90 behave in the presence of a nearly co-planar, Jupiter-like outer perturber with semimajor axes between 1 and 5.2 au. Most locations of the outer perturber do not affect the evolution of the inner planetary systems, apart from altering precession frequencies. However, there are locations at which an outer planet causes system instability due to, in part, secular eccentricity resonances. In Kepler-90, there is a range of orbital distances for which the outer perturber drives planets b and c, through secular interactions, onto orbits with inclinations that are ∼16° away from the rest of the planets. Kepler-90 is stable in this configuration. Such secular resonances can thus affect the observed multiplicity of transiting systems. We also compare the synthetic apsidal and nodal precession frequencies with the secular theory and find some misalignment between principal frequencies, indicative of strong interactions between the planets (consistent with the system showing TTVs). First-order libration angles are calculated to identify MMRs in the systems, for which two near-MMRs are shown in Kepler-90, with a 5:4 between b and c, as well as a 3:2 between g and h.

Solar system formation and the distribution of volatile species

NASA Technical Reports Server (NTRS)

Lunine, Jonathan I.

1994-01-01

To understand how the solar system formed we must understand the compositional distribution of the current system. Volatile species are particularly important in that their stability as condensed phases is limited in temperature-pressure space, and hence variations in their distribution at present potentially contain an imprint of processes by which temperature and pressure varied in the solar nebula. In this talk we restrict ourselves to species more volatile than water ice, and address issues related to processes in the outer solar system and the formation of bodies there; others in this conference will cover volatile species relevant to inner solar system processes. Study of the outer solar system is relevant both to understanding the interface between the solar nebula and the progenitor giant molecular cloud (since the chemical links to present-day observables in molecular clouds are species like methane, carbon monoxide, etc.), as well as the origin of terrestrial planet atmospheres and oceans (the latter to be covered by Owen). The wealth of compositional information on outer solar system bodies which has become available from spacecraft and ground-based observations challenges traditional simplistic views of the composition and hence dynamics of the solar nebula. The basic assumption of thermochemical equilibrium, promulgated in the 1950's, in which methane and ammonia dominate nitrogen- and carbon-bearing species, is demonstrably incorrect on both observational and theoretical grounds. However, the kinetic inhibition model which replaced it, in which carbon monoxide and molecular nitrogen dominate a nebula which is fully mixed and hence cycles outer solar system gases through a hot, chemically active zone near the disk center, is not supported either by observations. Instead, a picture of the outer solar system emerges in which the gas and grains are a mixture of relatively unaltered, or modestly altered, molecular cloud material, along with a fraction which has been chemically altered in the solar nebula itself (and perhaps giant planet nebulae).

Gravitational tides in the outer planets. I - Implications of classical tidal theory. II - Interior calculations and estimation of the tidal dissipation factor

NASA Technical Reports Server (NTRS)

Ioannou, Petros J.; Lindzen, Richard S.

1993-01-01

Classical tidal theory is applied to the atmospheres of the outer planets. The tidal geopotential due to satellites of the outer planets is discussed, and the solution of Laplace's tidal equation for Hough modes appropriate to tides on the outer planets is examined. The vertical structure of tidal modes is described, noting that only relatively high-order meridional mode numbers can propagate vertically with growing amplitude. Expected magnitudes for tides in the visible atmosphere of Jupiter are discussed. The classical theory is extended to planetary interiors taking the effects of spherically and self-gravity into account. The thermodynamic structure of Jupiter is described and the WKB theory of the vertical structure equation is presented. The regions for which inertial, gravity, and acoustic oscillations are possible are delineated. The case of a planet with a neutral interior is treated, discussing the various atmospheric boundary conditions and showing that the tidal response is small.

Mercury's Interior from MESSENGER Radio Science Data

NASA Astrophysics Data System (ADS)

Genova, A.; Mazarico, E.; Goossens, S. J.; Lemoine, F. G.; Neumann, G. A.; Smith, D. E.; Zuber, M. T.

2017-12-01

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft provided precise radio tracking data in orbit about Mercury for more than 4 years, from March 2011 to April 2015. These geodetic measurements enable us to investigate the interior structure of the planet from the inner core to the crust. The first three years of radio data allowed us to determine the gravity field of Mercury with a resolution of 150 km in the northern hemisphere (degree and order 50 in spherical harmonics) since the periapsis was located at higher latitudes (>65˚N) and 200-500 km altitudes. The comparison of this gravity solution with Mercury's topography, which was retrieved by using over 25 million individual measurements of the Mercury Laser Altimeter (MLA), resulted in a preliminary map of the crustal thickness of the planet. However, those results were limited by the resolution of the gravity field since the topography was defined in spherical harmonics up to degree and order 125. The last year of the MESSENGER extended mission was dedicated to a low-altitude campaign, where the spacecraft periapsis was maintained at altitudes between 25 and 100 km. The radio data collected during this mission phase allowed us to significantly improve the resolution of the gravity field locally in the northern hemisphere up to degree and order 100 in spherical harmonics. We present the gravity anomalies and crustal thickness maps that lead to a better understanding on the formation and evolution of specific regions. We present our estimated orientation model, which slightly differs from the solutions that were obtained by using Earth-based radar measurements and the co-registration of MESSENGER imaging and altimetry data. These previous estimates provide a direct measurement of the surface response, whereas the orientation model from gravity is more sensitive to the inner and outer core. A discrepancy between core and surface obliquities may provide fundamental information on the status of the outer core and the presence of a solid inner core. We also present the latest solution of the tidal Love number k2 that enables us to constrain the basal temperature and rigidity of the outer molten core.

Hubble 2020: Outer Planet Atmospheres Legacy (OPAL) Program

NASA Astrophysics Data System (ADS)

Simon, Amy

2017-08-01

Long time base observations of the outer planets are critical in understanding the atmospheric dynamics and evolution of the gas giants. We propose yearly monitoring of each giant planet for the remainder of Hubble's lifetime to provide a lasting legacy of increasingly valuable data for time-domain studies. The Hubble Space Telescope is a unique asset to planetary science, allowing high spatial resolution data with absolute photometric knowledge. For the outer planets, gas/ice giant planets Jupiter, Saturn, Uranus and Neptune, many phenomena happen on timescales of years to decades, and the data we propose are beyond the scope of a typical GO program. Hubble is the only platform that can provide high spatial resolution global studies of cloud coloration, activity, and motion on a consistent time basis to help constrain the underlying mechanics.

PIONEER VENUS 2 MULTI PROBE IS ENCAPSULATED IN PROTECTIVE SHROUD

NASA Technical Reports Server (NTRS)

1978-01-01

Encapsulation of the Pioneer Venus Multiprobe in its protective nose fairing is closely monitored by technicians in Hangar AO. The 2,000-pound spacecraft is one of two being launched toward the planet Venus. The Multiprobe is scheduled for launch aboard an Atlas Centaur rocket on August 7. Flying a direct path to the cloud-shrouded planet, the Multiprobe will reach Venus five days after the arrival of its sister spacecraft, the Pioneer Venus Orbiter, which was launched May 20, 1978. Three weeks before the Multiprobe reaches Venus, its four heavily instrumented scientific probes (seen on top of the spacecraft's main body or ''bus'') will be released and will impact at various points on the planet's surface. Together, the two spacecraft will conduct a thorough scientific exploration of the planet Venus.

Planetary and deep space requirements for photovoltaic solar arrays

NASA Technical Reports Server (NTRS)

Bankston, C. P.; Bennett, R. B.; Stella, P. M.

1995-01-01

In the past 25 years, the majority of interplanetary spacecraft have been powered by nuclear sources. However, as the emphasis on smaller, low cost missions gains momentum, the majority of missions now being planned will use photovoltaic solar arrays. This will present challenges to the solar array builders, inasmuch as planetary requirements usually differ from earth orbital requirements. In addition, these requirements often differ greatly, depending on the specific mission; for example, inner planets vs. outer planets, orbiters vs. flybys, spacecraft vs. landers, and so on. Also, the likelihood of electric propulsion missions will influence the requirements placed on solar array developers. The paper will discuss representative requirements for a range of planetary missions now in the planning stages. Insofar as inner planets are concerned, a Mercury orbiter is being studied with many special requirements. Solar arrays would be exposed to high temperatures and a potentially high radiation environment, and will need to be increasingly pointed off sun as the vehicle approaches Mercury. Identification and development of cell materials and arrays at high incidence angles will be critical to the design. Missions to the outer solar system that have been studied include a Galilean orbiter and a flight to the Kuiper belt. While onboard power requirements would be small (as low as 10 watts), the solar intensity will require relatively large array areas. As a result, such missions will demand extremely compact packaging and low mass structures to conform to launch vehicle constraints. In turn, the large are, low mass designs will impact allowable spacecraft loads. Inflatable array structures, with and without concentration, and multiband gap cells will be considered if available. In general, the highest efficiency cell technologies operable under low intensity, low temperature conditions are needed. Solar arrays will power missions requiring as little as approximately 100 watts, up to several kilowatts (at Earth) in the case of solar electric propulsion missions. Thus, mass and stowage volume minimization will be required over a range of array sizes. Concentrator designs, inflatable structures, and the combination of solar arrays with the telecommunications system have been proposed. Performance, launch vehicle constraints, an cost will be the principal parameters in the design trade space. Other special applications will also be discussed, including requirements relating to planetary landers and probes. In those cases, issues relating to shock loads on landing, operability in (possibly dusty) atmospheres, and extreme temperature cycles must be considered, in addition to performance, stowed volume, and costs.

Distant Saturn Sighting

NASA Technical Reports Server (NTRS)

2002-01-01

Saturn appears serene and majestic in the first color composite made of images taken by NASA's Cassini spacecraft on its approach to the ringed planet, with arrival still 20 months away.

The planet was 285 million kilometers (177 million miles) away from the spacecraft, nearly twice the distance between the Sun and Earth, when Cassini took images of it in various filters as an engineering test on Oct. 21, 2002.

It is summer in Saturn's southern hemisphere. The Sun is a lofty 27 degrees below the equator and casts a semi-circular shadow of the planet on the rings. The shadow extends partway across the rings, leaving the outer A ring in sunlight. The last Saturn-bound spacecraft, Voyager 2, arrived in early northern spring. Many features seen in Voyager images -- spoke-like markings on the rings, clouds and eddies in the hazy atmosphere, ring-shepherding moons -- are not yet visible to Cassini.

Titan, Saturn's largest moon, appears in the upper left. It is the only moon resolved from this distance. This composite uses a threefold enhancement in the brightness of Titan relative to the brightness of Saturn. Titan is a major attraction for scientists of the Cassini-Huygens mission. They will study its haze-enshrouded atmosphere and peer down, with special instrumentation, to its surface to look for evidence of organic processes similar to those that might have occurred on the early Earth, prior to the emergence of life.

Cassini will enter orbit around Saturn on July 1, 2004. It will release a piggybacked probe, Huygens, which will descend through Titan's atmosphere on Jan. 14, 2005.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. Information about the mission is available online at http://saturn.jpl.nasa.gov . The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Office of Space Science, Washington, D.C.

Outer planet probe engineering model structural tests

NASA Technical Reports Server (NTRS)

Smittkamp, J. A.; Gustin, W. H.; Griffin, M. W.

1977-01-01

A series of proof of concept structural tests was performed on an engineering model of the Outer Planets Atmospheric Entry Probe. The tests consisted of pyrotechnic shock, dynamic and static loadings. The tests partially verified the structural concept.

Environmental Test Program for the Mars Exploration Rover Project

NASA Technical Reports Server (NTRS)

Fisher, Terry C.; VanVelzer, Paul L.

2004-01-01

On June 10 and July 7, 2003 the National Aeronautics and Space Administration (NASA) launched two spacecraft from Cape Canaveral, Florida for a six (6) months flight to the Red Planet, Mars. The two Mars Exploration Rover spacecraft landed safely on the planet in January 2004. Prior to the successful launch, both of the spacecraft were involved in a comprehensive test campaign that included development, qualification, and protoflight test programs. Testing was performed to simulate the environments associated with launch, inter-planetary cruise, landing on the planet and Mars surface operations. Unique test requirements included operating the spacecraft while the chamber pressure was controlled to simulate the decent to the planet from deep space, high impact landing loads and rover operations on the surface of the planet at 8 Torr and -130 C. This paper will present an overview of the test program that included vibration, pyro-shock, landing loads, acoustic noise, thermal vacuum and solar simulation testing at the Jet Propulsion Laboratory (JPL) Environmental Test Laboratory facilities in Pasadena, California.

a Numerical Study of Close Approaches for a Cloud of Debris Considering Atmospheric Drag and Lift

NASA Astrophysics Data System (ADS)

Gomes, Vivian; Golebiewska, Justyna; Prado, Antonio

The present paper study close approaches between a group of debris and a planet. The dynamical model considers the atmosphere of the planet, both in terms of drag as well as lift. This cloud is created during the passage of the spacecraft by the atmosphere of the planet, which is the responsible by the explosion of the spacecraft. The dynamical system is compos by the planet, the Sun, and the spacecraft, which explodes and becomes a cloud of debris. The planet and the Sun are in circular planar orbits. The equations of motion are the ones of the circular planar restricted three-body problem with the addition of the forces given by the atmospheric: drag and lift. The planet Jupiter is used for the numerical simulations. The initial conditions of the spacecraft and the debris are specified at the periapsis, which is the point where the explosion occurs. The equations of motion are numerically integrated forward in time for each particle, until a point where the particle is at a distance that can be considered far enough from the planet and it is possible to disregard the effects of the planet and consider the Sun-particle as a two-body system. Then we compute the velocity, energy and angular momentum after the passage by the planet, for each particle, based in the two-body celestial mechanics. From those results, the eccentricity and the semi-major axis of each particle can be obtained. Then, the orbit of the spacecraft is integrated backwards in time, as a single body. The difference from the usual close approaches technique is the presence of the atmosphere of the planet, which generates a drag and a lift forces in the spacecraft, which causes the explosion and modifies the trajectories of the debris generated by the explosion. The primary objective of the present paper is to map the modifications of the orbits of the debris that compose the cloud due to the close approach with the planet. Emphasis is given to map the orbital parameters of the debris after the close approach with the planet. Then, the effects are compared with the same maneuvers performed without the inclusion of the atmosphere. This type of research is useful, because it helps to obtain the size and density of the cloud of debris after the passage, as a function of time. That information has impact on the evaluations of the risks that spacecrafts suffer when passing by shorter distances from this cloud.

Feasibility test of a solid state spin-scan photo-imaging system

NASA Technical Reports Server (NTRS)

Laverty, N. P.

1973-01-01

The feasibility of using a solid-state photo-imaging system to obtain resolution imagery from a Pioneer-type spinning spacecraft in future exploratory missions to the outer planets is discussed. Evaluation of the photo-imaging system performance, based on electrical video signal analysis recorded on magnetic tape, shows that the signal-to-noise (S/N) ratios obtained at low spatial frequencies exceed the anticipated performance and that measured modulation transfer functions exhibited some degradation in comparison with the estimated values, primarily owing to the difficulty in obtaining a precise focus of the optical system in the laboratory with the test patterns in close proximity to the objective lens. A preliminary flight model design of the photo-imaging system is developed based on the use of currently available phototransistor arrays. Image quality estimates that will be obtained are presented in terms of S/N ratios and spatial resolution for the various planets and satellites. Parametric design tradeoffs are also defined.

Dawn Auroral Breakup at Saturn Initiated by Auroral Arcs: UVIS/Cassini Beginning of Grand Finale Phase

NASA Astrophysics Data System (ADS)

Radioti, A.; Grodent, D.; Yao, Z. H.; Gérard, J.-C.; Badman, S. V.; Pryor, W.; Bonfond, B.

2017-12-01

We present Cassini auroral observations obtained on 11 November 2016 with the Ultraviolet Imaging Spectrograph at the beginning of the F-ring orbits and the Grand Finale phase of the mission. The spacecraft made a close approach to Saturn's southern pole and offered a remarkable view of the dayside and nightside aurora. With this sequence we identify, for the first time, the presence of dusk/midnight arcs, which are azimuthally spread from high to low latitudes, suggesting that their source region extends from the outer to middle/inner magnetosphere. The observed arcs could be auroral manifestations of plasma flows propagating toward the planet from the magnetotail, similar to terrestrial "auroral streamers." During the sequence the dawn auroral region brightens and expands poleward. We suggest that the dawn auroral breakup results from a combination of plasma instability and global-scale magnetic field reconfiguration, which is initiated by plasma flows propagating toward the planet. Alternatively, the dawn auroral enhancement could be triggered by tail magnetic reconnection.

The program at JPL to investigate the nuclear interaction of RTG's with scientific instruments on deep space probes

NASA Technical Reports Server (NTRS)

Truscello, V.

1972-01-01

A major concern in the integration of a radioisotope thermoelectric generator (RTG) with a spacecraft designed to explore the outer planets is the effect of the emitted radiation on the normal operation of scientific instruments. The necessary techniques and tools developed to allow accurate calculation of the neutron and gamma spectrum emanating from the RTG. The specific sources of radiation were identified and quantified. Monte Carlo techniques are then employed to perform the nuclear transport calculations. The results of these studies are presented. An extensive experimental program was initiated to measure the response of a number of scientific components to the nuclear radiation.

Testing for Dark Matter Trapped in the Solar System

NASA Technical Reports Server (NTRS)

Krisher, Timothy P.

1996-01-01

We consider the possibility of dark matter trapped in the solar system in bound solar orbits. If there exist mechanisms for dissipating excess kinetic energy by an amount sufficient for generating bound solar orbits, then trapping of galactic dark matter might have taken place during formation of the solar system, or could be an ongoing process. Possible locations for acumulation of trapped dark matter are orbital resonances with the planets or regions in the outer solar system. It is posible to test for the presence of unseen matter by detecting its gravitational effects. Current results for dynamical limits obtained from analyses of planetary ephemeris data and spacecraft tracking data are presented. Possible future improvements are discussed.

Laboratory evaluation and application of microwave absorption properties under simulated conditions for planetary atmospheres

NASA Technical Reports Server (NTRS)

Steffes, Paul G.

1987-01-01

Radio absorptivity data for planetary atmospheres obtained from spacecraft radio occultation experiments and Earth-based radio astronomical observations can be used to infer abundances of microwave absorbing atmospheric constituents in those atmospheres, as long as reliable information regarding the microwave absorping properties of potential constituents is available. The use of theoretically derived microwave absorption properties for such atmospheric constituents, or laboratory measurements of such properties under environmental conditions which are significantly different than those of the planetary atmosphere being studied, often leads to significant misinterpretation of available opacity data. Laboratory measurement of the microwave properties of atmospheric gases under simulated conditions for the outer planets were conducted. Results of these measurements are discussed.

Galileo magnetometer measurements: a stronger case for a subsurface ocean at Europa.

PubMed

Kivelson, M G; Khurana, K K; Russell, C T; Volwerk, M; Walker, R J; Zimmer, C

2000-08-25

On 3 January 2000, the Galileo spacecraft passed close to Europa when it was located far south of Jupiter's magnetic equator in a region where the radial component of the magnetospheric magnetic field points inward toward Jupiter. This pass with a previously unexamined orientation of the external forcing field distinguished between an induced and a permanent magnetic dipole moment model of Europa's internal field. The Galileo magnetometer measured changes in the magnetic field predicted if a current-carrying outer shell, such as a planet-scale liquid ocean, is present beneath the icy surface. The evidence that Europa's field varies temporally strengthens the argument that a liquid ocean exists beneath the present-day surface.

Galileo Magnetometer Measurements: A Stronger Case for a Subsurface Ocean at Europa

NASA Astrophysics Data System (ADS)

Kivelson, Margaret G.; Khurana, Krishan K.; Russell, Christopher T.; Volwerk, Martin; Walker, Raymond J.; Zimmer, Christophe

2000-08-01

On 3 January 2000, the Galileo spacecraft passed close to Europa when it was located far south of Jupiter's magnetic equator in a region where the radial component of the magnetospheric magnetic field points inward toward Jupiter. This pass with a previously unexamined orientation of the external forcing field distinguished between an induced and a permanent magnetic dipole moment model of Europa's internal field. The Galileo magnetometer measured changes in the magnetic field predicted if a current-carrying outer shell, such as a planet-scale liquid ocean, is present beneath the icy surface. The evidence that Europa's field varies temporally strengthens the argument that a liquid ocean exists beneath the present-day surface.

Ground Based Studies of the Outer Planets

NASA Technical Reports Server (NTRS)

Trafton, Laurence M.

2005-01-01

This report covers progress to date under this grant on our continuing program to conduct ground based studies of the outer solar system planets and satellites, with emphasis on spectroscopy and atmospheric phenomena. The research continues under our new PAST grant, NNG04G131G beginning 5/1/2004. The original period of performance of the subject grant was 3/1/2001 to 2/28/2004, but was extended one year at no cost. Although there is some overlap in the scientific projects conducted during the extended year with those of the new grant, this report is confined to the portion of the work funded under NAG5-10435. The primary goals for this grant period were a comparative study of outer planet thermospheres/ionospheres near solar maximum, extended to the mid-IR, and the investigation of molecular dimers in outer solar system atmospheres. This project supports NASA's planned space missions, Jupiter Polar Orbiter, outer Planet Microprobes, and the recent Cassini flyby of Jupiter. It also supports the OSS strategic plan themes, The Exploration of the Solar System and The Sun-Earth Connection/ Understanding comparative planetary space environments.

A Distant Solar System Artist Concept

NASA Image and Video Library

2004-12-09

This artist concept depicts a distant hypothetical solar system, similar in age to our own. Looking inward from the system outer fringes, a ring of dusty debris can be seen, and within it, planets circling a star the size of our Sun. This debris is all that remains of the planet-forming disk from which the planets evolved. Planets are formed when dusty material in a large disk surrounding a young star clumps together. Leftover material is eventually blown out by solar wind or pushed out by gravitational interactions with planets. Billions of years later, only an outer disk of debris remains. These outer debris disks are too faint to be imaged by visible-light telescopes. They are washed out by the glare of the Sun. However, NASA's Spitzer Space Telescope can detect their heat, or excess thermal emission, in infrared light. This allows astronomers to study the aftermath of planet building in distant solar systems like our own. http://photojournal.jpl.nasa.gov/catalog/PIA07096

Constraining the Properties of Small Stars and Small Planets Observed by K2

NASA Astrophysics Data System (ADS)

Dressing, Courtney D.; Newton, Elisabeth R.; Charbonneau, David; Schlieder, Josh; Hawaii/California/Arizona/Indiana K2 Follow-up Consortium, HARPS-N Consortium

2016-01-01

We are using the results of the NASA K2 mission (the second career of the Kepler spacecraft) to study how the frequency and architectures of planetary systems orbiting M dwarfs throughout the ecliptic plane compare to those of the early M dwarf planetary systems observed by Kepler. In a previous analysis of the Kepler data set, we found that planets orbiting early M dwarfs are common: we measured a cumulative planet occurrence rate of 2.45 +/- 0.22 planets per M dwarf with periods of 0.5-200 days and planet radii of 1-4 Earth radii. Within a conservative habitable zone based on the moist greenhouse inner limit and maximum greenhouse outer limit, we estimated an occurrence rate of 0.15 (+0.18/-0.06) Earth-size planets and 0.09 (+0.10/-0.04) super-Earths per M dwarf HZ. Applying these occurrence rates to the population of nearby stars and assuming that mid- and late-M dwarfs host planets at the same rate as early M dwarfs, we predicted that the nearest potentially habitable Earth-size planet likely orbits an M dwarf a mere 2.6 ± 0.4 pc away. We are now testing the assumption of equal planet occurrence rates for M dwarfs of all types by inspecting the population of planets detected by K2 and conducting follow-up observations of planet candidate host stars to identify false positives and better constrain system parameters. I will present the results of recent observing runs with SpeX on the IRTF to obtain near-infrared spectra of low-mass stars targeted by K2 and determine the radii, temperatures, and metallicities of our target stars using empirical relations. We gratefully acknowledge funding from the NASA XRP Program, the John Templeton Foundation, and the NASA Sagan Fellowship Program.

Giant planets: Clues on current and past organic chemistry in the outer solar system

NASA Technical Reports Server (NTRS)

Pollack, James B.; Atreya, Sushil K.

1992-01-01

The giant planets of the outer solar system - Jupiter, Saturn, Uranus, and Neptune - were formed in the same flattened disk of gas and dust, the solar nebula, as the terrestrial planets were. Yet, the giant planets differ in some very fundamental ways from the terrestrial planets. Despite enormous differences, the giant planets are relevant to exobiology in general and the origin of life on the Earth in particular. The giant planets are described as they are today. Their basic properties and the chemistry occurring in their atmospheres is discussed. Theories of their origin are explored and aspects of these theories that may have relevance to exobiology and the origin of life on Earth are stressed.

Effects of Extreme Obliquity Variations on the Habitability of Exoplanets

NASA Technical Reports Server (NTRS)

Armstrong, J. C.; Barnes, R.; Domagal-Goldman, S.; Breiner, J.; Quinn, T. R.; Meadows, V. S.

2014-01-01

We explore the impact of obliquity variations on planetary habitability in hypothetical systems with high mutual inclination. We show that large-amplitude, high-frequency obliquity oscillations on Earth-like exoplanets can suppress the ice-albedo feedback, increasing the outer edge of the habitable zone. We restricted our exploration to hypothetical systems consisting of a solar-mass star, an Earth-mass planet at 1 AU, and 1 or 2 larger planets. We verified that these systems are stable for 108 years with N-body simulations and calculated the obliquity variations induced by the orbital evolution of the Earth-mass planet and a torque from the host star. We ran a simplified energy balance model on the terrestrial planet to assess surface temperature and ice coverage on the planet's surface, and we calculated differences in the outer edge of the habitable zone for planets with rapid obliquity variations. For each hypothetical system, we calculated the outer edge of habitability for two conditions: (1) the full evolution of the planetary spin and orbit and (2) the eccentricity and obliquity fixed at their average values. We recovered previous results that higher values of fixed obliquity and eccentricity expand the habitable zone, but we also found that obliquity oscillations further expand habitable orbits in all cases. Terrestrial planets near the outer edge of the habitable zone may be more likely to support life in systems that induce rapid obliquity oscillations as opposed to fixed-spin planets. Such planets may be the easiest to directly characterize with space-borne telescopes.

The Initial Physical Conditions of Kepler-36 b and c

NASA Astrophysics Data System (ADS)

Owen, James E.; Morton, Timothy. D.

2016-03-01

The Kepler-36 planetary system consists of two exoplanets at similar separations (0.115 and 0.128 au), which have dramatically different densities. The inner planet has a density consistent with an Earth-like composition, while the outer planet is extremely low density, such that it must contain a voluminous H/He envelope. Such a density difference would pose a problem for any formation mechanism if their current densities were representative of their composition at formation. However, both planets are at close enough separations to have undergone significant evaporation in the past. We constrain the core mass, core composition, initial envelope mass, and initial cooling time of each planet using evaporation models conditioned on their present-day masses and radii, as inferred from Kepler photometry and transit timing analysis. The inner planet is consistent with being an evaporatively stripped core, while the outer planet has retained some of its initial envelope due to its higher core mass. Therefore, both planets could have had a similar formation pathway, with the inner planet having an initial envelope-mass fraction of ≲10% and core mass of ˜4.4 M⊕, while the outer had an initial envelope-mass fraction of the order of 15%-30% and core mass ˜7.3 M⊕. Finally, our results indicate that the outer planet had a long (≳30 Myr) initial cooling time, much longer than would naively be predicted from simple timescale arguments. The long initial cooling time could be evidence for a dramatic early cooling episode such as the recently proposed “boil-off” process.

Shaping HR8799's outer dust belt with an unseen planet

NASA Astrophysics Data System (ADS)

Read, M. J.; Wyatt, M. C.; Marino, S.; Kennedy, G. M.

2018-04-01

HR8799 is a benchmark system for direct imaging studies. It hosts two debris belts, which lie internally and externally to four giant planets. This paper considers how the four known planets and a possible fifth planet interact with the external population of debris through N-body simulations. We find that when only the known planets are included, the inner edge of the outer belt predicted by our simulations is much closer to the outermost planet than recent ALMA observations suggest. We subsequently include a fifth planet in our simulations with a range of masses and semimajor axes, which is external to the outermost known planet. We find that a fifth planet with a mass and semimajor axis of 0.1 MJ and 138 au predicts an outer belt that agrees well with ALMA observations, whilst remaining stable for the lifetime of HR8799 and lying below current direct imaging detection thresholds. We also consider whether inward scattering of material from the outer belt can input a significant amount of mass into the inner belt. We find that for the current age of HR8799, only ˜1 per cent of the mass-loss rate of the inner disc can be replenished by inward scattering. However, we find that the higher rate of inward scattering during the first ˜10 Myr of HR8799 would be expected to cause warm dust emission at a level similar to that currently observed, which may provide an explanation for such bright emission in other systems at ˜10 Myr ages.

Effects of extreme obliquity variations on the habitability of exoplanets.

PubMed

Armstrong, J C; Barnes, R; Domagal-Goldman, S; Breiner, J; Quinn, T R; Meadows, V S

2014-04-01

We explore the impact of obliquity variations on planetary habitability in hypothetical systems with high mutual inclination. We show that large-amplitude, high-frequency obliquity oscillations on Earth-like exoplanets can suppress the ice-albedo feedback, increasing the outer edge of the habitable zone. We restricted our exploration to hypothetical systems consisting of a solar-mass star, an Earth-mass planet at 1 AU, and 1 or 2 larger planets. We verified that these systems are stable for 10(8) years with N-body simulations and calculated the obliquity variations induced by the orbital evolution of the Earth-mass planet and a torque from the host star. We ran a simplified energy balance model on the terrestrial planet to assess surface temperature and ice coverage on the planet's surface, and we calculated differences in the outer edge of the habitable zone for planets with rapid obliquity variations. For each hypothetical system, we calculated the outer edge of habitability for two conditions: (1) the full evolution of the planetary spin and orbit and (2) the eccentricity and obliquity fixed at their average values. We recovered previous results that higher values of fixed obliquity and eccentricity expand the habitable zone, but we also found that obliquity oscillations further expand habitable orbits in all cases. Terrestrial planets near the outer edge of the habitable zone may be more likely to support life in systems that induce rapid obliquity oscillations as opposed to fixed-spin planets. Such planets may be the easiest to directly characterize with space-borne telescopes.

Debris disks as signposts of terrestrial planet formation. II. Dependence of exoplanet architectures on giant planet and disk properties

NASA Astrophysics Data System (ADS)

Raymond, S. N.; Armitage, P. J.; Moro-Martín, A.; Booth, M.; Wyatt, M. C.; Armstrong, J. C.; Mandell, A. M.; Selsis, F.; West, A. A.

2012-05-01

We present models for the formation of terrestrial planets, and the collisional evolution of debris disks, in planetary systems that contain multiple marginally unstable gas giants. We previously showed that in such systems, the dynamics of the giant planets introduces a correlation between the presence of terrestrial planets and cold dust, i.e., debris disks, which is particularly pronounced at λ ~ 70 μm. Here we present new simulations that show that this connection is qualitatively robust to a range of parameters: the mass distribution of the giant planets, the width and mass distribution of the outer planetesimal disk, and the presence of gas in the disk when the giant planets become unstable. We discuss how variations in these parameters affect the evolution. We find that systems with equal-mass giant planets undergo the most violent instabilities, and that these destroy both terrestrial planets and the outer planetesimal disks that produce debris disks. In contrast, systems with low-mass giant planets efficiently produce both terrestrial planets and debris disks. A large fraction of systems with low-mass (M ≲ 30 M⊕) outermost giant planets have final planetary separations that, scaled to the planets' masses, are as large or larger than the Saturn-Uranus and Uranus-Neptune separations in the solar system. We find that the gaps between these planets are not only dynamically stable to test particles, but are frequently populated by planetesimals. The possibility of planetesimal belts between outer giant planets should be taken into account when interpreting debris disk SEDs. In addition, the presence of ~ Earth-mass "seeds" in outer planetesimal disks causes the disks to radially spread to colder temperatures, and leads to a slow depletion of the outer planetesimal disk from the inside out. We argue that this may explain the very low frequency of >1 Gyr-old solar-type stars with observed 24 μm excesses. Our simulations do not sample the full range of plausible initial conditions for planetary systems. However, among the configurations explored, the best candidates for hosting terrestrial planets at ~1 AU are stars older than 0.1-1 Gyr with bright debris disks at 70 μm but with no currently-known giant planets. These systems combine evidence for the presence of ample rocky building blocks, with giant planet properties that are least likely to undergo destructive dynamical evolution. Thus, we predict two correlations that should be detected by upcoming surveys: an anti-correlation between debris disks and eccentric giant planets and a positive correlation between debris disks and terrestrial planets. Three movies associated to Figs. 1, 3, and 7 are available in electronic form at http://www.aanda.org

A planetary dust ring generated by impact-ejection from the Galilean satellites

NASA Astrophysics Data System (ADS)

Sachse, Manuel

2018-03-01

All outer planets in the Solar System are surrounded by a ring system. Many of these rings are dust rings or they contain at least a high proportion of dust. They are often formed by impacts of micro-meteoroids onto embedded bodies. The ejected material typically consists of micron-sized charged particles, which are susceptible to gravitational and non-gravitational forces. Generally, detailed information on the dynamics and distribution of the dust requires expensive numerical simulations of a large number of particles. Here we develop a relatively simple and fast, semi-analytical model for an impact-generated planetary dust ring governed by the planet's gravity and the relevant perturbation forces for the dynamics of small charged particles. The most important parameter of the model is the dust production rate, which is a linear factor in the calculation of the dust densities. We apply our model to dust ejected from the Galilean satellites using production rates obtained from flybys of the dust sources. The dust densities predicted by our model are in good agreement with numerical simulations and with in situ measurements by the Galileo spacecraft. The lifetimes of large particles are about two orders of magnitude greater than those of small ones, which implies a flattening of the size distribution in circumplanetary space. Information about the distribution of circumplanetary dust is also important for the risk assessment of spacecraft orbits in the respective regions.

The Neptune/Triton Explorer Mission: A Concept Feasibility Study

NASA Technical Reports Server (NTRS)

Esper, Jaime

2003-01-01

Technological advances over the next 10 to 15 years promise to enable a number of smaller, more capable science missions to the outer planets. With the inception of miniaturized spacecraft for a wide range of applications, both in large clusters around Earth, and for deep space missions, NASA is currently in the process of redefining the way science is being gathered. Technologies such as 3-Dimensional Multi-Chip Modules, Micro-machined Electromechanical Devices, Multi Functional Structures, miniaturized transponders, miniaturized propulsion systems, variable emissivity thermal coatings, and artificial intelligence systems are currently in research and development, and are scheduled to fly (or have flown) in a number of missions. This study will leverage on these and other technologies in the design of a lightweight Neptune orbiter unlike any other that has been proposed to date. The Neptune/Triton Explorer (NExTEP) spacecraft uses solar electric earth gravity assist and aero capture maneuvers to achieve its intended target orbit. Either a Taurus or Delta-class launch vehicle may be used to accomplish the mission.

Reactor/Brayton power systems for nuclear electric spacecraft

NASA Technical Reports Server (NTRS)

Layton, J. P.

1980-01-01

Studies are currently underway to assess the technological feasibility of a nuclear-reactor-powered spacecraft propelled by electric thrusters. This vehicle would be capable of performing detailed exploration of the outer planets of the solar system during the remainder of this century. The purpose of this study was to provide comparative information on a closed cycle gas turbine power conversion system. The results have shown that the performance is very competitive and that a 400 kWe space power system is dimensionally compatible with a single Space Shuttle launch. Performance parameters of system mass and radiator area were determined for systems from 100 to 1000 kWe. A 400 kWe reference system received primary attention. The components of this system were defined and a conceptual layout was developed with encouraging results. The preliminary mass determination for the complete power system was very close to the desired goal of 20 kg/kWe. Use of more advanced technology (higher turbine inlet temperature) will substantially improve system performance characteristics.

Saturn B Ring, Finer Than Ever

NASA Image and Video Library

2017-01-30

This image shows a region in Saturn's outer B ring. NASA's Cassini spacecraft viewed this area at a level of detail twice as high as it had ever been observed before. And from this view, it is clear that there are still finer details to uncover. Researchers have yet to determine what generated the rich structure seen in this view, but they hope detailed images like this will help them unravel the mystery. In order to preserve the finest details, this image has not been processed to remove the many small bright blemishes, which are created by cosmic rays and charged particle radiation near the planet. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Dec. 18, 2016. The view was obtained at a distance of approximately 32,000 miles (51,000 kilometers) from the rings, and looks toward the unilluminated side of the rings. Image scale is about a quarter-mile (360 meters) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA21058

Rocket exhaust plume impingement on the Voyager spacecraft

NASA Technical Reports Server (NTRS)

Baerwald, R. K.

1978-01-01

In connection with the conduction of the long-duration Voyager missions to the outer planets and the sophisticated propulsion systems required, it was necessary to carry out an investigation to avoid exhaust plume impingement problems. The rarefied gas dynamics literature indicates that, for most engineering surfaces, the assumption of diffuse reemission and complete thermal accommodation is warranted in the free molecular flow regime. This assumption was applied to an analysis of a spacecraft plume impingement problem in the near-free molecular flow regime and yielded results to within a few percent of flight data. The importance of a correct treatment of the surface temperature was also demonstrated. Specular reflection, on the other hand, was shown to yield results which may be unconservative by a factor of 2 or 3. It is pointed out that one of the most difficult portions of an exhaust plume impingement analysis is the simulation of the impinged hardware. The geometry involved must be described as accurately and completely as possible.

Formation of Large Regular Satellites of Giant Planets in an Extended Gaseous Nebula: Subnebula Model and Accretion of Satellites

NASA Technical Reports Server (NTRS)

Mosqueira, I.; Estrada, P. R.

2000-01-01

We model the subnebulae of Jupiter and Saturn wherein satellite accretion took place. We expect a giant planet subnebula to be composed of an optically thick (given gaseous opacity) inner region inside of the planet's centrifugal radius (located at r(sub c, sup J) = l5R(sub J) for Jupiter and r(sub c, sup S) = 22R(sub S) for Saturn), and an optically thin, extended outer disk out to a fraction of the planet's Roche lobe, which we choose to be R(sub roche)/5 (located at approximately 150R(sub J) near the inner irregular satellites for Jupiter, and approximately 200R(sub S) near Phoebe for Saturn). This places Titan and Ganymede in the inner disk, Callisto and Iapetus in the outer disk, and Hyperion in the transition region. The inner disk is the leftover of the gas accreted by the protoplanet. The outer disk results from the solar torque on nebula gas flowing into the protoplanet during the time of giant planet gap opening. For the sake of specificity, we use a cosmic mixture 'minimum mass' model to constrain the gas densities of the inner disks of Jupiter and Saturn (and also Uranus). For the total mass of the outer disk we use the simple scaling M(sub disk) = M(sub P)tau(sub gap)/tau(sub acc), where M(sub P) is the mass of the giant planet, tau(sub gap) is the gap opening timescale, and tau(sub acc) is the giant planet accretion time. This gives a total outer disk mass of approximately 100M(sub Callisto) for Jupiter and possibly approximately 200M(sub Iapetus) for Saturn (which contain enough condensables to form Callisto and Iapetus respectively). Our model has Ganymede at a subnebula temperature of approximately 250 K and Titan at approximately 100 K. The outer disks of Jupiter and Saturn have constant temperatures of 130 K and 90 K respectively.

Laboratory Simulations of Martian and Venusian Aeolian Processes

NASA Technical Reports Server (NTRS)

Greeley, Ronald

1999-01-01

With the flyby of the Neptune system by Voyager, the preliminary exploration of the Solar System was accomplished. Data have been returned for all major planets and satellites except the Pluto system. Results show that the surfaces of terrestrial planets and satellites have been subjected to a wide variety of geological processes. On solid- surface planetary objects having an atmosphere, aeolian processes are important in modifying their surfaces through the redistribution of fine-grained material by the wind. Bedrock may be eroded to produce particles and the particles transported by wind for deposition in other areas. This process operates on Earth today and is evident throughout the geological record. Aeolian processes also occur on Mars, Venus, and possibly Titan and Triton, both of which are outer planet satellites that have atmospheres. Mariner 9 and Viking results show abundant wind-related landforms on Mars, including dune fields and yardangs (wind-eroded hills). On Venus, measurements made by the Soviet Venera and Vega spacecraft and extrapolations from the Pioneer Venus atmospheric probes show that surface winds are capable of transporting particulate materials and suggest that aeolian processes may operate on that planet as well. Magellan radar images of Venus show abundant wind streaks in some areas, as well as dune fields and a zone of possible yardangs. The study of planetary aeolian processes must take into account diverse environments, from the cold, low-density atmosphere of Mars to the extremely hot, high- density Venusian atmosphere. Factors such as threshold wind speeds (minimum wind velocity needed to move particles), rates of erosion and deposition, trajectories of windblown particles, and aeolian flow fields over various landforms are all important aspects of the problem. In addition, study of aeolian terrains on Earth using data analogous to planetary data-collection systems is critical to the interpretation of spacecraft information and places constraints on results from numerical models and laboratory simulations.

The planet Saturn (1970)

NASA Technical Reports Server (NTRS)

1972-01-01

The present-day knowledge on Saturn and its environment are described for designers of spacecraft which are to encounter and investigate the planet. The discussion includes physical properties of the planet, gravitational field, magnetic and electric fields, electromagnetic radiation, satellites and meteoroids, the ring system, charged particles, atmospheric composition and structure, and clouds and atmospheric motions. The environmental factors which have pertinence to spacecraft design criteria are also discussed.

Patched Conic Trajectory Code

NASA Technical Reports Server (NTRS)

Park, Brooke Anderson; Wright, Henry

2012-01-01

PatCon code was developed to help mission designers run trade studies on launch and arrival times for any given planet. Initially developed in Fortran, the required inputs included launch date, arrival date, and other orbital parameters of the launch planet and arrival planets at the given dates. These parameters include the position of the planets, the eccentricity, semi-major axes, argument of periapsis, ascending node, and inclination of the planets. With these inputs, a patched conic approximation is used to determine the trajectory. The patched conic approximation divides the planetary mission into three parts: (1) the departure phase, in which the two relevant bodies are Earth and the spacecraft, and where the trajectory is a departure hyperbola with Earth at the focus; (2) the cruise phase, in which the two bodies are the Sun and the spacecraft, and where the trajectory is a transfer ellipse with the Sun at the focus; and (3) the arrival phase, in which the two bodies are the target planet and the spacecraft, where the trajectory is an arrival hyperbola with the planet as the focus.

Advanced space storable propellants for outer planet exploration

NASA Technical Reports Server (NTRS)

Thunnissen, Daniel P.; Guernsey, Carl S.; Baker, Raymond S.; Miyake, Robert N.

2004-01-01

An evaluation of the feasibility and mission performance benefits of using advanced space storable propellants for outer planet exploration was performed. For the purpose of this study, space storable propellants are defined to be propellants which can be passively stored without the need for active cooling.

Effects of Extreme Obliquity Variations on the Habitability of Exoplanets

PubMed Central

Barnes, R.; Domagal-Goldman, S.; Breiner, J.; Quinn, T.R.; Meadows, V.S.

2014-01-01

Abstract We explore the impact of obliquity variations on planetary habitability in hypothetical systems with high mutual inclination. We show that large-amplitude, high-frequency obliquity oscillations on Earth-like exoplanets can suppress the ice-albedo feedback, increasing the outer edge of the habitable zone. We restricted our exploration to hypothetical systems consisting of a solar-mass star, an Earth-mass planet at 1 AU, and 1 or 2 larger planets. We verified that these systems are stable for 108 years with N-body simulations and calculated the obliquity variations induced by the orbital evolution of the Earth-mass planet and a torque from the host star. We ran a simplified energy balance model on the terrestrial planet to assess surface temperature and ice coverage on the planet's surface, and we calculated differences in the outer edge of the habitable zone for planets with rapid obliquity variations. For each hypothetical system, we calculated the outer edge of habitability for two conditions: (1) the full evolution of the planetary spin and orbit and (2) the eccentricity and obliquity fixed at their average values. We recovered previous results that higher values of fixed obliquity and eccentricity expand the habitable zone, but we also found that obliquity oscillations further expand habitable orbits in all cases. Terrestrial planets near the outer edge of the habitable zone may be more likely to support life in systems that induce rapid obliquity oscillations as opposed to fixed-spin planets. Such planets may be the easiest to directly characterize with space-borne telescopes. Key Words: Exoplanets—Habitable zone—Energy balance models. Astrobiology 14, 277–291. PMID:24611714

Signatures of Young Planets in the Continuum Emission from Protostellar Disks

NASA Astrophysics Data System (ADS)

Isella, Andrea; Turner, Neal J.

2018-06-01

Many protostellar disks show central cavities, rings, or spiral arms likely caused by low-mass stellar or planetary companions, yet few such features are conclusively tied to bodies embedded in the disks. We note that even small features on the disk surface cast shadows, because the starlight grazes the surface. We therefore focus on accurately computing the disk thickness, which depends on its temperature. We present models with temperatures set by the balance between starlight heating and radiative cooling, which are also in vertical hydrostatic equilibrium. The planet has 20, 100, or 1000 M ⊕, ranging from barely enough to perturb the disk significantly, to clearing a deep tidal gap. The hydrostatic balance strikingly alters the appearance of the model disk. The outer walls of the planet-carved gap puff up under starlight heating, throwing a shadow across the disk beyond. The shadow appears in scattered light as a dark ring that could be mistaken for a gap opened by another more distant planet. The surface brightness contrast between outer wall and shadow for the 1000 M ⊕ planet is an order of magnitude greater than a model neglecting the temperature disturbances. The shadow is so deep that it largely hides the planet-launched outer arm of the spiral wave. Temperature gradients are such that outer low-mass planets undergoing orbital migration will converge within the shadow. Furthermore, the temperature perturbations affect the shape, size, and contrast of features at millimeter and centimeter wavelengths. Thus radiative heating and cooling are key to the appearance of protostellar disks with embedded planets.

Self-Organization of Zonal Jets in Outer Planet Atmospheres: Uranus and Neptune

NASA Technical Reports Server (NTRS)

Friedson, A. James

1997-01-01

The statistical mechnical theory of a two-dimensional Euler fluid is appleid for the first time to explore the spontaneous self-oganization of zonal jets in outer planet atmospheres. Globally conserved integralls of motion are found to play a central role in defining jet structure.

Gravity, Topography, and Magnetic Field of Mercury from Messenger

NASA Technical Reports Server (NTRS)

Neumann, Gregory A.; Solomon, Sean C.; Zuber, Maria T.; Phillips, Roger J.; Barnouin, Olivier; Ernst, Carolyn; Goosens, Sander; Hauck, Steven A., II; Head, James W., III; Johnson, Catherine L.;

Spacecraft transfer trajectory design exploiting resonant orbits in multi-body environments

NASA Astrophysics Data System (ADS)

Vaquero Escribano, Tatiana Mar

Historically, resonant orbits have been employed in mission design for multiple planetary flyby trajectories and, more recently, as a source of long-term orbital stability. For instance, in support of a mission concept in NASA's Outer Planets Program, the Jupiter Europa Orbiter spacecraft is designed to encounter two different resonances with Europa during the 'endgame' phase, leading to Europa orbit insertion on the final pass. In 2011, the Interstellar Boundary Explorer spacecraft was inserted into a stable out-of-plane lunar-resonant orbit, the first of this type for a spacecraft in a long-term Earth orbit. However, resonant orbits have not yet been significantly explored as transfer mechanisms between non-resonant orbits in multi-body systems. This research effort focuses on incorporating resonant orbits into the design process to potentially enable the construction of more efficient or even novel transfer scenarios. Thus, the goals in this investigation are twofold: i) to expand the orbit architecture in multi-body environments by cataloging families of resonant orbits, and ii) to assess the role of such families in the design of transfer trajectories with specific patterns and itineraries. The benefits and advantages of employing resonant orbits in the design process are demonstrated through a variety of astrodynamics applications in several multi-body systems. In the Earth-Moon system, locally optimal transfer trajectories from low Earth orbit to selected libration point orbits are designed by leveraging conic arcs and invariant manifolds associated with resonant orbits. Resonant manifolds in the Earth-Moon system offer trajectories that tour the entire space within reasonable time intervals, facilitating the design of libration point orbit tours as well as Earth-Moon cyclers. In the Saturnian system, natural transitions between resonant and libration point orbits are sought and the problem of accessing Hyperion from orbits that are resonant with Titan is also examined. To add versatility to the proposed design method, a system translation technique enables the straightforward transition of solutions from the Earth-Moon system to any Sun-planet or planet-moon three-body system. The circular restricted three-body problem serves as a basis to quickly generate solutions that meet specific requirements, but candidate transfer trajectories are then transitioned to an ephemeris model for validation.

Solar Power System Analyses for Electric Propulsion Missions

NASA Technical Reports Server (NTRS)

Kerslake, Thomas W.; Gefert, Leon P.

1999-01-01

Solar electric propulsion (SEP) mission architectures are applicable to a wide range of NASA missions including human Mars exploration and robotic exploration of the outer planets. In this paper, we discuss the conceptual design and detailed performance analysis of an SEP stage electric power system (EPS). EPS performance, mass and area predictions are compared for several PV array technologies. Based on these studies, an EPS design for a 1-MW class, Human Mars Mission SEP stage was developed with a reasonable mass, 9.4 metric tons, and feasible deployed array area, 5800 sq m. An EPS was also designed for the Europa Mapper spacecraft and had a mass of 151 kg and a deployed array area of 106 sq m.

Guidance and navigation requirements for unmanned flyby and swingby missions to the outer planets. Volume 2: impulsive high thrust missions, phase A

NASA Technical Reports Server (NTRS)

1969-01-01

The impulsive, high thrust missions portion of a study on guidance and navigation requirements for unmanned flyby and swingby missions to the outer planet is presented. The proper balance between groundbased navigational capability, using the deep space network (DSN) alone, and an onboard navigational capability with and without supplemental use of DSN tracking, for unmanned missions to the outer planets of the solar system is defined. A general guidance and navigation requirements program is used to survey parametrically the characteristics associated with three types of navigation systems: (1) totally onboard, (2) totally Earth-based, and (3) a combination of these two.

NEWLY DISCOVERED PLANETS ORBITING HD 5319, HD 11506, HD 75784 AND HD 10442 FROM THE N2K CONSORTIUM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Giguere, Matthew J.; Fischer, Debra A.; Brewer, John M.

2015-01-20

Initially designed to discover short-period planets, the N2K campaign has since evolved to discover new worlds at large separations from their host stars. Detecting such worlds will help determine the giant planet occurrence at semi-major axes beyond the ice line, where gas giants are thought to mostly form. Here we report four newly discovered gas giant planets (with minimum masses ranging from 0.4 to 2.1 M {sub Jup}) orbiting stars monitored as part of the Next 2000 target stars (N2K) Doppler Survey program. Two of these planets orbit stars already known to host planets: HD 5319 and HD 11506. Themore » remaining discoveries reside in previously unknown planetary systems: HD 10442 and HD 75784. The refined orbital period of the inner planet orbiting HD 5319 is 641 days. The newly discovered outer planet orbits in 886 days. The large masses combined with the proximity to a 4:3 mean motion resonance make this system a challenge to explain with current formation and migration theories. HD 11506 has one confirmed planet, and here we confirm a second. The outer planet has an orbital period of 1627.5 days, and the newly discovered inner planet orbits in 223.6 days. A planet has also been discovered orbiting HD 75784 with an orbital period of 341.7 days. There is evidence for a longer period signal; however, several more years of observations are needed to put tight constraints on the Keplerian parameters for the outer planet. Lastly, an additional planet has been detected orbiting HD 10442 with a period of 1043 days.« less

History of Hubble Space Telescope (HST)

NASA Image and Video Library

1980-01-01

This illustration shows the Hubble Space Telescope's (HST's) major configuration elements. The spacecraft has three interacting systems: The Support System Module (SSM), an outer structure that houses the other systems and provides services such as power, communication, and control; The Optical Telescope Assembly (OTA), which collects and concentrates the incoming light in the focal plane for use by the Scientific Instruments (SI); and five SIs. The SI Control and Data Handling (CDH) unit controls the five SI's, four that are housed in an aft section focal plane structure and one that is placed along the circumference of the spacecraft. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST detects objects 25 times fainter than the dimmest objects seen from Earth and provides astronomers with an observable universe 250 times larger than visible from ground-based telescopes, perhaps as far away as 14 billion light-years. The HST views galaxies, stars, planets, comets, possibly other solar systems, and even unusual phenomena such as quasars, with 10 times the clarity of ground-based telescopes. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Cornecticut, developed the optical system and guidance sensors. The Lockheed Missile and Space Company of Sunnyvale, California produced the protective outer shroud and spacecraft systems, and assembled and tested the finished telescope.

Remote Thermal IR Spectroscopy of our Solar System

NASA Technical Reports Server (NTRS)

Kostiuk, Theodor; Hewagama, Tilak; Goldstein, Jeffrey; Livengood, Timothy; Fast, Kelly

1999-01-01

Indirect methods to detect extrasolar planets have been successful in identifying a number of stars with companion planets. No direct detection of an extrasolar planet has yet been reported. Spectroscopy in the thermal infrared region provides a potentially powerful approach to detection and characterization of planets and planetary systems. We can use knowledge of our own solar system, its planets and their atmospheres to model spectral characteristics of planets around other stars. Spectra derived from modeling our own solar system seen from an extrasolar perspective can be used to constrain detection strategies, identification of planetary class (terrestrial vs. gaseous) and retrieval of chemical, thermal and dynamical information. Emission from planets in our solar system peaks in the thermal infrared region, approximately 10 - 30 microns, substantially displaced from the maximum of the much brighter solar emission in the visible near 0.5 microns. This fact provides a relatively good contrast ratio to discriminate between stellar (solar) and planetary emission and optimize the delectability of planetary spectra. Important molecular constituents in planetary atmospheres have rotational-vibrational spectra in the thermal infrared region. Spectra from these molecules have been well characterized in the laboratory and studied in the atmospheres of solar system planets from ground-based and space platforms. The best example of such measurements are the studies with Fourier transform spectrometers, the Infrared Interferometer Spectrometers (IRIS), from spacecraft: Earth observed from NIMBUS 8, Mars observed from Mariner 9, and the outer planets observed from Voyager spacecraft. An Earth-like planet is characterized by atmospheric spectra of ozone, carbon dioxide, and water. Terrestrial planets have oxidizing atmospheres which are easily distinguished from reducing atmospheres of gaseous giant planets which lack oxygen-bearing species and are characterized by spectra containing hydrocarbons such as methane and ethane. Spectroscopic information on extrasolar planets thus can permit their classification. Spectra and spectral lines contain information on the temperature structure of the atmosphere. Line and band spectra can be used to identify the molecular constituents and retrieve species abundances, thereby classifying and characterizing the planet. At high enough spectral resolution characteristic planetary atmospheric dynamics and unique phenomena such as failure of local thermodynamic equilibrium can be identified. Dynamically induced effects such as planetary rotation and orbital velocity shift and change the shape of spectral features and must be modeled in detailed spectral studies. We will use our knowledge of the compositional, thermal and dynamical characteristics of planetary atmospheres in our own solar system to model spectra observed remotely on similar planets in extrasolar planetary systems. We will use a detailed radiative transfer and beam integration program developed for the modeling and interpretation of thermal infrared spectra measured from nearby planet planets to generate models of an extra-solar "Earth" and "Jupiter". From these models we will show how key spectral features distinguish between terrestrial and gaseous planets, what information can be obtained with different spectral resolution, what spectral features can be used to search for conditions for biogenic activity, and how dynamics and distance modify the observed spectra. We also will look at unique planetary phenomena such as atmospheric lasing and discuss their utility as probes for detection and identification of planets. Results of such studies will provide information to constrain design for instrumentation needed to directly detect extrasolar planets.

ScienceCast 136: A Sudden Multiplication of Planets

NASA Image and Video Library

2014-02-26

Today, NASA announced a breakthrough addition to the catalog of new planets. Researchers using Kepler have confirmed 715 new worlds, almost quadrupling the number of planets previously confirmed by the planet-hunting spacecraft.

Solar System, in Perspective

NASA Image and Video Library

2014-03-24

This artist's concept puts solar system distances in perspective. The scale bar is in astronomical units, with each set distance beyond 1 AU representing 10 times the previous distance. One AU is the distance from the sun to the Earth, which is about 93 million miles or 150 million kilometers. Neptune, the most distant planet from the sun, is about 30 AU. Informally, the term "solar system" is often used to mean the space out to the last planet. Scientific consensus, however, says the solar system goes out to the Oort Cloud, the source of the comets that swing by our sun on long time scales. Beyond the outer edge of the Oort Cloud, the gravity of other stars begins to dominate that of the sun. The inner edge of the main part of the Oort Cloud could be as close as 1,000 AU from our sun. The outer edge is estimated to be around 100,000 AU. NASA's Voyager 1, humankind's most distant spacecraft, is around 125 AU. Scientists believe it entered interstellar space, or the space between stars, on Aug. 25, 2012. Much of interstellar space is actually inside our solar system. It will take about 300 years for Voyager 1 to reach the inner edge of the Oort Cloud and possibly about 30,000 years to fly beyond it. Alpha Centauri is currently the closest star to our solar system. But, in 40,000 years, Voyager 1 will be closer to the star AC +79 3888 than to our own sun. AC +79 3888 is actually traveling faster toward Voyager 1 than the spacecraft is traveling toward it. The Voyager spacecraft were built and continue to be operated by NASA's Jet Propulsion Laboratory, in Pasadena, Calif. Caltech manages JPL for NASA. The Voyager missions are a part of NASA's Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate at NASA Headquarters in Washington. For more information about Voyager, visit: www.nasa.gov/voyager and voyager.jpl.nasa.gov . Image credit: NASA/JPL-Caltech NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

The Constraint of Coplanarity: Compact multi-planet system outer architectures and formation.-UP

NASA Astrophysics Data System (ADS)

Jontof-Hutter, Daniel

The Kepler mission discovered 92 systems with 4 or more transiting exoplanets. Systems like Kepler-11 with six "mini-Neptunes" on orbital periods well inside that of Venus pose a challenge to planet formation theory which is broadly split into two competing paradigms. One theory invokes the formation of Neptunes beyond the "snow line", followed by inward migration and assembly into compact configurations near the star. The alternative is that low density planets form in situ at all distances in the protoplanetary nebula. The two paradigms disagree on the occurrence of Jovian planets at longer orbital periods than the transiting exoplanets since such massive planets would impede the inward migration of multiple volatile-rich planets to within a fraction of 1 AU. The likelihood of all the known planets at systems like Kepler-11 to be transiting is very sensitive to presence of outer Jovian planets for a wide range in orbital distance and relative inclination of the Jovian planet. This can put upper limits on the occurrence of Jovian planets by the condition that the six known planets have to have low mutual inclinations most of the time in order for their current cotransiting state to be plausible. Most of these systems have little or no RV data. Hence, our upper limits may be the best constraints on the occurrence of Jovian planets in compact co-planar systems for years to come, and may help distinguish the two leading paradigms of planet formation theory. Methodology. We propose to use an established n-body code (MERCURY) to perform long-term simulations of systems like Kepler-11 with the addition of a putative Jovian planet considering a range of orbital distances. These simulations will test for which initial conditions a Jovian planet would prevent the known planets from all transiting at the same time. We will 1) determine at what orbital distances and inclinations an outer Jovian planet would make the observed configuration of Kepler-11 very unlikely. 2) Test the effect of an undetected planet in the large dynamical space between Kepler-11 f and Kepler 11 g on our upper limits on a Jovian outer planet. 3) Repeat the analysis for all compact systems of 4 or more transiting planets with published planetary masses (including Kepler-79, Kepler-33, and Kepler-80) 5) Repeat the analysis for all systems of 4 or more transiting planets where the condition of long-term orbital stability provides useful upper limits on planetary masses, using their orbital periods and an appropriate mass-radius relation. 6) Measure an upper limit on the occurrence rate of outer Jovian planets. If we find an occurrence rate significantly lower than the known occurrence rate of Jovian planets from RV surveys, this would be evidence in support of the migration model as Jovian planets are expected impede the assembly of compact coplanar systems of low-density planets close to the host star. Relevance. According to the XRP Solicitation, investigations are expected to directly support the goal of "understanding exoplanetary systems", by doing one or more of the following..."improve understanding of the origins of exoplanetary systems". This proposal will help distinguish between competing paradigms in planet formation with dynamical modeling, and hence will improve our understanding of the origins of exoplanetary systems. This proposal will in no way require analysis of archival Kepler data, and relies only on the published masses, radii and orbital periods of high muliplicity systems discovered by Kepler. Therefore, our proposal is not appropriate for ADAP.

Small space reactor power systems for unmanned solar system exploration missions

NASA Technical Reports Server (NTRS)

Bloomfield, Harvey S.

1987-01-01

A preliminary feasibility study of the application of small nuclear reactor space power systems to the Mariner Mark II Cassini spacecraft/mission was conducted. The purpose of the study was to identify and assess the technology and performance issues associated with the reactor power system/spacecraft/mission integration. The Cassini mission was selected because study of the Saturn system was identified as a high priority outer planet exploration objective. Reactor power systems applied to this mission were evaluated for two different uses. First, a very small 1 kWe reactor power system was used as an RTG replacement for the nominal spacecraft mission science payload power requirements while still retaining the spacecraft's usual bipropellant chemical propulsion system. The second use of reactor power involved the additional replacement of the chemical propulsion system with a small reactor power system and an electric propulsion system. The study also provides an examination of potential applications for the additional power available for scientific data collection. The reactor power system characteristics utilized in the study were based on a parametric mass model that was developed specifically for these low power applications. The model was generated following a neutronic safety and operational feasibility assessment of six small reactor concepts solicited from U.S. industry. This assessment provided the validation of reactor safety for all mission phases and generatad the reactor mass and dimensional data needed for the system mass model.

Visible and Near-IR Imaging of Giant Planets: Outer Manifestations of Deeper Secrets

NASA Astrophysics Data System (ADS)

Hammel, Heidi B.

1996-09-01

Visible and near-infrared imaging of the giant planets -- Jupiter, Saturn, Uranus, and Neptune -- probes the outermost layers of clouds in these gaseous atmospheres. Not only are the images beautiful and striking in their color and diversity of detail, they also provide quantitative clues to the dynamical and chemical processes taking place both at the cloud tops and deeper in the interior: zonal wind profiles can be extracted; wavelength-dependent center-to-limb brightness variations yield valuable data for modeling vertical aerosol structure; the presence of planetary-scale atmospheric waves can sometimes be deduced; variations of cloud color and brightness with latitude provide insight into the underlying mechanisms driving circulation; development and evolution of discrete atmospheric features trace both exogenic and endogenic events. During the 1980's, our understanding of the giant planets was revolutionized by detailed visible-wavelength images taken by the Voyager spacecraft of these planets' atmospheres. However, those images were static: brief snapshots in time of four complex and dynamic atmospheric systems. In short, those images no longer represent the current appearance of these planets. Recently, our knowledge of the atmospheres of the gas giant planets has undergone major new advances, due in part to the excellent imaging capability and longer-term temporal sampling of the Hubble Space Telescope (HST) and the Galileo Mission to Jupiter. In this talk, I provide an update on our current understanding of the gas giants based on recent visible and near-infrared imaging, highlighting results from the collision of Comet Shoemaker-Levy 9 with Jupiter, Saturn's White Spots, intriguing changes in the atmosphere of Uranus, and Neptune's peripatetic clouds.

Pioneer 10: Beyond the Known Planets.

ERIC Educational Resources Information Center

Waller, Peter

1983-01-01

On June 13, 1983, the U.S. unmanned spacecraft, "Pioneer 10," will cross the orbit of Neptune. This first flight beyond the planets is being celebrated by the National Aeronautics and Space Administration and other groups. Discusses what the spacecraft will observe and types of data it will collect. (JN)

Dynamical Constraints on Nontransiting Planets Orbiting TRAPPIST-1

NASA Astrophysics Data System (ADS)

Jontof-Hutter, Daniel; Truong, Vinh H.; Ford, Eric B.; Robertson, Paul; Terrien, Ryan C.

2018-06-01

We derive lower bounds on the orbital distance and inclination of a putative planet beyond the transiting seven planets of TRAPPIST-1, for a range of masses ranging from 0.08 M Jup to 3.5 M Jup. While the outer architecture of this system will ultimately be constrained by radial velocity measurements over time, we present dynamical constraints from the remarkably coplanar configuration of the seven transiting planets, which is sensitive to modestly inclined perturbers. We find that the observed configuration is unlikely if a Jovian-mass planet inclined by ≥3° to the transiting planet exists within 0.53 au, exceeding any constraints from transit timing variations (TTV) induced in the known planets from an undetected perturber. Our results will inform RV programs targeting TRAPPIST-1, and for near coplanar outer planets, tighter constraints are anticipated for radial velocity (RV) precisions of ≲140 m s‑1. At higher inclinations, putative planets are ruled out to greater orbital distances with orbital periods up to a few years.

A likely planet-induced gap in the disc around T Cha

NASA Astrophysics Data System (ADS)

Hendler, Nathanial P.; Pinilla, Paola; Pascucci, Ilaria; Pohl, Adriana; Mulders, Gijs; Henning, Thomas; Dong, Ruobing; Clarke, Cathie; Owen, James; Hollenbach, David

2018-03-01

We present high-resolution (0.11 × 0.06 arcsec2) 3 mm ALMA observations of the highly inclined transition disc around the star T Cha. Our continuum image reveals multiple dust structures: an inner disc, a spatially resolved dust gap, and an outer ring. When fitting sky-brightness models to the real component of the 3 mm visibilities, we infer that the inner emission is compact (≤1 au in radius), the gap width is between 18 and 28 au, and the emission from the outer ring peaks at ˜36 au. We compare our ALMA image with previously published 1.6 μm VLT/SPHERE imagery. This comparison reveals that the location of the outer ring is wavelength dependent. More specifically, the peak emission of the 3 mm ring is at a larger radial distance than that of the 1.6 μm ring, suggesting that millimeter-sized grains in the outer disc are located farther away from the central star than micron-sized grains. We discuss different scenarios to explain our findings, including dead zones, star-driven photoevaporation, and planet-disc interactions. We find that the most likely origin of the dust gap is from an embedded planet, and estimate - for a single planet scenario - that T Cha's gap is carved by a 1.2MJup planet.

Limit cycles at the outer edge of the habitable zone

NASA Astrophysics Data System (ADS)

Haqq-Misra, J. D.; Kopparapu, R.; Batalha, N. E.; Harman, C.; Kasting, J. F.

2016-12-01

The liquid water habitable zone (HZ) describes the orbital distance at which a terrestrial planet can maintain above-freezing conditions through regulation by the carbonate-silicate cycle. Calculations with one-dimensional climate models predict that the inner edge of the HZ is limited by water loss through a runaway greenhouse, while the outer edge of the HZ is bounded by the maximum greenhouse effect of carbon dioxide. This classic picture of the HZ continues to guide interpretation of exoplanet discoveries; however, recent calculations have shown that terrestrial planets near the outer edge of the HZ may exhibit other behaviors that affect their habitability. Here I discuss results from a hierarchy of climate models to understand the stellar environments most likely to support a habitable planet. I present energy balance climate model calculations showing the conditions under which planets in the outer regions of the habitable zone should oscillate between long, globally glaciated states and shorter periods of climatic warmth, known as `limit cycles.' Such conditions would be inimical to the development of complex land life, including intelligent life. Limit cycles may also provide an explanation for fluvial features on early Mars, although this requires additional greenhouse warming by hydrogen. These calculations show that the net volcanic outgassing rate and the propensity for plant life to sequester carbon dioxide are critical factors that determine the susceptibility of a planet to limit cycling. I argue that planets orbiting mid G- to mid K-type stars offer more opportunity for supporting advanced life than do planets around F-type stars or M-type stars.

Chairmanship of the Neptune/Pluto Outer Planets Science Working Group

NASA Technical Reports Server (NTRS)

Stern, S. Alan

1992-01-01

The Outer Planets Science Working Group (OPSWG) is the NASA Solar System Exploration Division (SSED) scientific steering committee for the Outer Solar Systems missions. The FY92 activities of OPSWG are summarized. A set of objectives for OPSWG over FY93 are described. OPSWG's activities for subsequent years are outlined. A paper which examines scientific questions motivating renewed exploration of the Neptune/Triton system and which reviews the technical results of the mission studies completed to date is included in the appendix.

HAT-P-44b, HAT-P-45b, AND HAT-P-46b: Three transiting hot Jupiters in possible multi-planet systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hartman, J. D.; Bakos, G. Á.; Bhatti, W.

2014-06-01

We report the discovery by the HATNet survey of three new transiting extrasolar planets orbiting moderately bright (V = 13.2, 12.8, and 11.9) stars. The planets have orbital periods of 4.3012, 3.1290, and 4.4631 days, masses of 0.35, 0.89, and 0.49 M {sub J}, and radii of 1.24, 1.43, and 1.28 R {sub J}. The stellar hosts have masses of 0.94, 1.26, and 1.28 M {sub ☉}. Each system shows significant systematic variations in its residual radial velocities, indicating the possible presence of additional components. Based on its Bayesian evidence, the preferred model for HAT-P-44 consists of two planets, includingmore » the transiting component, with the outer planet having a period of 872 days, eccentricity of 0.494 ± 0.081, and a minimum mass of 4.0 M {sub J}. Due to aliasing we cannot rule out alternative solutions for the outer planet having a period of 220 days or 438 days. For HAT-P-45, at present there is not enough data to justify the additional free parameters included in a multi-planet model; in this case a single-planet solution is preferred, but the required jitter of 22.5 ± 6.3 m s{sup –1} is relatively high for a star of this type. For HAT-P-46 the preferred solution includes a second planet having a period of 78 days and a minimum mass of 2.0 M {sub J}, however the preference for this model over a single-planet model is not very strong. While substantial uncertainties remain as to the presence and/or properties of the outer planetary companions in these systems, the inner transiting planets are well characterized with measured properties that are fairly robust against changes in the assumed models for the outer planets. Continued radial velocity monitoring is necessary to fully characterize these three planetary systems, the properties of which may have important implications for understanding the formation of hot Jupiters.« less

An extrasolar planetary system with three Neptune-mass planets.

PubMed

Lovis, Christophe; Mayor, Michel; Pepe, Francesco; Alibert, Yann; Benz, Willy; Bouchy, François; Correia, Alexandre C M; Laskar, Jacques; Mordasini, Christoph; Queloz, Didier; Santos, Nuno C; Udry, Stéphane; Bertaux, Jean-Loup; Sivan, Jean-Pierre

2006-05-18

Over the past two years, the search for low-mass extrasolar planets has led to the detection of seven so-called 'hot Neptunes' or 'super-Earths' around Sun-like stars. These planets have masses 5-20 times larger than the Earth and are mainly found on close-in orbits with periods of 2-15 days. Here we report a system of three Neptune-mass planets with periods of 8.67, 31.6 and 197 days, orbiting the nearby star HD 69830. This star was already known to show an infrared excess possibly caused by an asteroid belt within 1 au (the Sun-Earth distance). Simulations show that the system is in a dynamically stable configuration. Theoretical calculations favour a mainly rocky composition for both inner planets, while the outer planet probably has a significant gaseous envelope surrounding its rocky/icy core; the outer planet orbits within the habitable zone of this star.

Stability Analysis of the Planetary System Orbiting Upsilon Andromedae

NASA Technical Reports Server (NTRS)

Lissauer, Jack J.; Rivera, Eugenio J.; DeVincenzi, Donald (Technical Monitor)

2000-01-01

We present results of long-term numerical orbital integrations designed to test the stability of the three-planet system orbiting Upsilon Andromedae and short-term integrations to test whether mutual perturbations among the planets can be used to determine planetary masses. Our initial conditions are based on the latest fits to the radial velocity data obtained by the planet-search group at Lick Observatory. The new fits result in significantly more stable systems than did the initially announced planetary parameters. An analytic analysis of the star and the two outer planets shows that this subsystem is Hill stable up to five. Our integrations involving all three planets show that the system is stable for at least 100 Myr for up to four. In our simulations, we still see a secular resonance between the outer two planets and in some cases large oscillations in the eccentricity of the inner planet.

NASA 1981 photography index

NASA Technical Reports Server (NTRS)

1982-01-01

An index of representative photographs is presented. Color transparencies and black and white glossies of major launches, Mariner spacecraft, Pioneer spacecraft, planets and other space phenomena, Skylab, space shuttle, Viking spacecraft, and Voyager spacecraft are included.

Planet Formation by Coagulation: A Focus on Uranus and Neptune

NASA Astrophysics Data System (ADS)

Goldreich, Peter; Lithwick, Yoram; Sari, Re'em

2004-09-01

Planets form in the circumstellar disks of young stars. We review the basic physical processes by which solid bodies accrete each other and alter each others' random velocities, and we provide order-of-magnitude derivations for the rates of these processes. We discuss and exercise the two-groups approximation, a simple yet powerful technique for solving the evolution equations for protoplanet growth. We describe orderly, runaway, neutral, and oligarchic growth. We also delineate the conditions under which each occurs. We refute a popular misconception by showing that the outer planets formed quickly by accreting small bodies. Then we address the final stages of planet formation. Oligarchy ends when the surface density of the oligarchs becomes comparable to that of the small bodies. Dynamical friction is no longer able to balance viscous stirring and the oligarchs' random velocities increase. In the inner-planet system, oligarchs collide and coalesce. In the outer-planet system, some of the oligarchs are ejected. In both the inner- and outer-planet systems, this stage ends once the number of big bodies has been reduced to the point that their mutual interactions no longer produce large-scale chaos. Subsequently, dynamical friction by the residual small bodies circularizes and flattens their orbits. The final stage of planet formation involves the clean up of the residual small bodies. Clean up has been poorly explored.

Variety in planetary systems

NASA Technical Reports Server (NTRS)

Wetherill, George W.

1993-01-01

Observation of circumstellar disks, regular satellite systems of outer planets, and planet-size objects orbiting pulsars support the supposition that formation of planetary systems is a robust, rather than a fragile, byproduct of the formation and evolution of stars. The extent to which these systems may be expected to resemble one another and our Solar System, either in overall structure or in detail remains uncertain. When the full range of possible stellar masses, disk masses, and initial specific angular momenta are considered, the possible variety of planetary configurations is very large. Numerical modeling indicates a difference between the formation of small, inner, terrestrial planets and the outer planets.

Mars’ Growth Stunted by an Early Giant Planet Instability

NASA Astrophysics Data System (ADS)

Clement, Matthew; Kaib, Nathan A.; Raymond, Sean N.; Walsh, Kevin J.

2017-10-01

Many dynamical aspects of the solar system can be explained by the outer planets experiencing a period of orbital instability. Though often correlated with a perceived delayed spike in the lunar cratering record known as the Late Heavy Bombardment (LHB), recent work suggests that this event may have occurred during the epoch of terrestrial planet formation. Though current simulations of terrestrial accretion can reproduce many observed qualities of the solar system, replicating the small mass of Mars requires modification to standard planet formation models. Here we use direct numerical simulations to show that an early instability in the outer solar system regularly yields properly sized Mars analogues. In 80% of simulations, we produce a Mars of the appropriate mass. Our most successful outcomes occur when the terrestrial planets evolve 10 million years (Myr), and accrete several Mars sized embryos in the Mars forming region before the instability takes place. Mars is left behind as a stranded embryo, while the remainder of these bodies are either ejected from the system or scattered towards the inner solar system where they deliver water to Earth. An early giant planet instability can thus replicate both the inner and outer solar system in a single model.

NASA's Dawn Mission to Asteroid 4 Vesta

NASA Technical Reports Server (NTRS)

McFadden, Lucyann A.

2011-01-01

NASA's Dawn Mission to asteroid 4 Vesta is part of a 13-year robotic space project designed to reveal the nature of two of the largest asteroids in the Main Asteroid Belt of our Solar System. Ceres and Vesta are two complementary terrestrial protoplanets whose accretion was probably terminated by the formation of Jupiter. They provide a bridge in our understanding between the rocky bodies of the inner solar system and the icy bodies of the outer solar system. Ceres appears to be undifferentiated Vesta has experienced significant heating and likely differentiation. Both formed very early in history of the solar system and while suffering many impacts have remained intact, thereby retaining a record of events and processes from the time of planet formation. Detailed study of the geophysics and geochemistry of these two bodies provides critical benchmarks for early solar system conditions and processes that shaped its subsequent evolution. Dawn provides the missing context for both primitive and evolved meteoritic data, thus playing a central role in understanding terrestrial planet formation and the evolution of the asteroid belt. Dawn is to he launched in 2006 arriving at Vesta in 20l0 and Ceres in 2014, stopping at each to make 11 months of orbital measurements. The spacecraft uses solar electric propulsion, both in cruise and in orbit, to make most efficient use of its xenon propellant. The spacecraft carries a framing camera, visible and infrared mapping spectrometer, gamma ray/neutron magnetometer, and radio science.

Definition phase of Grand Tour missions/radio science investigations study for outer planets missions

NASA Technical Reports Server (NTRS)

Tyler, G. L.

1972-01-01

Scientific instrumentation for satellite communication and radio tracking systems in the outer planet exploration mission is discussed. Mission planning considers observations of planetary and satellite-masses, -atmospheres, -magnetic fields, -surfaces, -gravitational fields, solar wind composition, planetary radio emissions, and tests of general relativity in time delay and ray bending experiments.

Dynamics of a Probable Earth-mass Planet in the GJ 832 System

NASA Astrophysics Data System (ADS)

Satyal, S.; Griffith, J.; Musielak, Z. E.

2017-08-01

The stability of planetary orbits around the GJ 832 star system, which contains inner (GJ 832c) and outer (GJ 832b) planets, is investigated numerically and a detailed phase-space analysis is performed. Special attention is given to the existence of stable orbits for a planet less than 15 M ⊕ that is injected between the inner and outer planets. Thus, numerical simulations are performed for three and four bodies in elliptical orbits (or circular for special cases) by using a large number of initial conditions that cover the selected phase-spaces of the planet’s orbital parameters. The results presented in the phase-space maps for GJ 832c indicate the least deviation of eccentricity from its nominal value, which is then used to determine its inclination regime relative to the star-outer planet plane. Also, the injected planet is found to display stable orbital configurations for at least one billion years. Then, the radial velocity curves based on the signature from the Keplerian motion are generated for the injected planets with masses 1 M ⊕ to 15 M ⊕ in order to estimate their semimajor axes and mass limits. The synthetic RV signal suggests that an additional planet of mass ≤15 M ⊕ with a dynamically stable configuration may be residing between 0.25 and 2.0 au from the star. We have provided an estimated number of RV observations for the additional planet that is required for further observational verification.

An Overview of the Juno Mission to Jupiter

NASA Technical Reports Server (NTRS)

Grammier, Richard S.

2006-01-01

Arriving in orbit around the planet Jupiter in 2016 after a five-year journey, the Juno spacecraft will begin a one-year investigation of the gas giant in order to understand its origin and evolution by determining its water abundance and constraining its core mass. In addition, Juno will map the planet's magnetic and gravitational fields, map its atmosphere, and explore the three-dimensional structure of Jupiter's polar magnetosphere and auroras. Juno will discriminate among different models for giant planet formation. These investigations will be conducted over the course of thirty-two 11-day elliptical polar orbits of the planet. The orbits are designed to avoid Jupiter's highest radiation regions. The spacecraft is a spinning, solar-powered system carrying a complement of eight science instruments for conducting the investigations. The spacecraft systems and instruments take advantage of significant design and operational heritage from previous space missions.

Thermodynamics of clathrate hydrate at low and high pressures with application to the outer solar system

NASA Technical Reports Server (NTRS)

Lunine, J. I.; Stevenson, D. J.

1985-01-01

The thermodynamic stability of clathrate hydrate is calculated to predict the formation conditions corresponding to a range of solar system parameters. The calculations were performed using the statistical mechanical theory developed by van der Waals and Platteeuw (1959) and existing experimental data concerning clathrate hydrate and its components. Dissociation pressures and partition functions (Langmuir constants) are predicted at low pressure for CO clathrate (hydrate) using the properties of chemicals similar to CO. It is argued that nonsolar but well constrained noble gas abundances may be measurable by the Galileo spacecraft in the Jovian atmosphere if the observed carbon enhancement is due to bombardment of the atmosphere by clathrate-bearing planetesimals sometime after planetary formation. The noble gas abundances of the Jovian satellite Titan are predicted, assuming that most of the methane in Titan is accreted as clathrate. It is suggested that under thermodynamically appropriate conditions, complete clathration of water ice could have occurred in high-pressure nebulas around giant planets, but probably not in the outer solar nebula. The stability of clathrate in other pressure ranges is also discussed.

Quasi-periodic 1-hour pulsations in the Saturn's outer magnetosphere

NASA Astrophysics Data System (ADS)

Rusaitis, L.; Khurana, K. K.; Walker, R. J.; Kivelson, M.

2017-12-01

Pulsations in the Saturn's magnetic field and particle fluxes of approximately 1-hour periodicity have been frequently detected in the outer Saturnian magnetosphere by the Cassini spacecraft since 2004. These particle and magnetic field enhancements have been typically observed more often in the dusk sector of the planet, and mid to high latitudes. We investigate nearly 200 of these events as detected by the magnetometer and the Cassini Low-Energy Magnetospheric Measurement System detector (LEMMS) data during the 2004-2015 time frame to characterize these pulsations and suggest their origin. The mechanism needed to produce these observed enhancements needs to permit the acceleration of the energetic electrons to a few MeV and a variable periodicity of enhancements from 40 to 90 minutes. We examine the relation of the oscillations to the periodic power modulations in Saturn kilometric radiation (SKR), using the SKR phase model of Kurth et al. [2007] and Provan et al. [2011]. Finally, we show that similar pulsations can also be observed at 2.5-D MHD simulations of Saturn's magnetosphere.

Interior Studies with BepiColombo's MPO

NASA Astrophysics Data System (ADS)

Benkhoff, Johannes; Zender, Joe

2017-04-01

NASA's MESSENGER mission has fundamentally changed our view of the innermost planet. Mercury is in many ways a very different planet from what we were expecting. Now BepiColombo has to follow up on answering the fundamental questions that MESSENGER raised and go beyond. BepiColombo is a joint project between ESA and the Japanese Aerospace Exploration Agency (JAXA). The Mission consists of two orbiters, the Mercury Planetary Orbiter (MPO) and the Mercury Magnetospheric Orbiter (MMO). The mission scenario foresees a launch of both spacecraft with an ARIANE V in October 2018 and an arrival at Mercury in 2025. From their dedicated orbits the two spacecraft will be studying the planet and its environment. The MPO scientific payload comprises eleven instruments/instrument packages; several of them dedicated to the study of the interior. Together, these instruments will perform measurements to enhance our knowledge of the planets figure and internal structure and composition. Expected results will provide further clues to the origin and evolution of a planet close to its parent star. In this presentation we will give an overview on the expected science return of BepiColombo with respect to the interior. In addition we give a brief update on the latest development status of the mission. All scientific instruments have been integrated into the spacecraft and both spacecraft are now under final acceptance testing.

The effects of correlated noise in intra-complex DSN arrays for S-band Galileo telemetry reception

NASA Technical Reports Server (NTRS)

Dewey, R. J.

1992-01-01

A number of the proposals for supporting a Galileo S-band (2.3-GHz) mission involve arraying several antennas to maximize the signal-to-noise ratio (and bit rate) obtainable from a given set of antennas. Arraying is no longer a new idea, having been used successfully during the Voyager encounters with Uranus and Neptune. However, arraying for Galileo's tour of Jupiter is complicated by Jupiter's strong radio emission, which produces correlated noise effects. This article discusses the general problem of correlated noise due to a planet, or other radio source, and applies the results to the specific case of an array of antennas at the DSN's Tidbinbilla, Australia, complex (DSS 42, DSS 43, DSS 45, and the yet-to-be-built DSS 34). The effects of correlated noise are highly dependent on the specific geometry of the array and on the spacecraft-planet configuration; in some cases, correlated noise effects produce an enhancement, rather than a degradation, of the signal-to-noise ratio. For the case considered here--an array of the DSN's Australian antennas observing Galileo and Jupiter--there are three regimes of interest. If the spacecraft-planet separation is approximately less than 75 arcsec, the average effect of correlated noise is a loss of signal to noise (approximately 0.2 dB as the spacecraft-planet separation approaches zero). For spacecraft-planet separations approximately greater than 75 arcsec, but approximately less than 400 arcsec, the effects of correlated noise cause signal-to-noise variations as large as several tenths of a decibel over time scales of hours or changes in spacecraft-planet separation of tens of arcseconds; however, on average its effects are small (less than 0.01 dB). When the spacecraft is more than 400 arcsec from Jupiter (as is the case for about half of Galileo's tour), correlated noise is a less than 0.05-dB effect.

Gravity-assist engine for space propulsion

NASA Astrophysics Data System (ADS)

Bergstrom, Arne

2014-06-01

As a possible alternative to rockets, the present article describes a new type of engine for space travel, based on the gravity-assist concept for space propulsion. The new engine is to a great extent inspired by the conversion of rotational angular momentum to orbital angular momentum occurring in tidal locking between astronomical bodies. It is also greatly influenced by Minovitch's gravity-assist concept, which has revolutionized modern space technology, and without which the deep-space probes to the outer planets and beyond would not have been possible. Two of the three gravitating bodies in Minovitch's concept are in the gravity-assist engine discussed in this article replaced by an extremely massive ‘springbell' (in principle a spinning dumbbell with a powerful spring) incorporated into the spacecraft itself, and creating a three-body interaction when orbiting around a gravitating body. This makes gravity-assist propulsion possible without having to find suitably aligned astronomical bodies. Detailed numerical simulations are presented, showing how an actual spacecraft can use a ca 10-m diameter springbell engine in order to leave the earth's gravitational field and enter an escape trajectory towards interplanetary destinations.

Bi-lobed Shape of Comet 67P from a Collapsed Binary

NASA Astrophysics Data System (ADS)

Nesvorný, David; Parker, Joel; Vokrouhlický, David

2018-06-01

The Rosetta spacecraft observations revealed that the nucleus of comet 67P/Churyumov–Gerasimenko consists of two similarly sized lobes connected by a narrow neck. Here, we evaluate the possibility that 67P is a collapsed binary. We assume that the progenitor of 67P was a binary and consider various physical mechanisms that could have brought the binary components together, including small-scale impacts and gravitational encounters with planets. We find that 67P could be a primordial body (i.e., not a collisional fragment) if the outer planetesimal disk lasted ≲10 Myr before it was dispersed by migrating Neptune. The probability of binary collapse by impact is ≃30% for tightly bound binaries. Most km-class binaries become collisionally dissolved. Roughly 10% of the surviving binaries later evolve to become contact binaries during the disk dispersal, when bodies suffer gravitational encounters with Neptune. Overall, the processes described in this work do not seem to be efficient enough to explain the large fraction (∼67%) of bi-lobed cometary nuclei inferred from spacecraft imaging.

BepiColombo the next step to explore Mercury - Status update and Science goals

NASA Astrophysics Data System (ADS)

Benkhoff, Johannes; Fujimoto, Masaki; Zender, Joe

2016-04-01

NASA's MESSENGER mission has fundamentally changed our view of the innermost planet. Mercury is in many ways a very different planet from what we were expecting. Now BepiColombo has to follow up on answering the fundamental questions that MESSENGER raised and go beyond. BepiColombo is a joint project between ESA and the Japanese Aerospace Exploration Agency (JAXA). The Mission consists of two orbiters, the Mercury Planetary Orbiter (MPO) and the Mercury Magnetospheric Orbiter (MMO). The mission scenario foresees a launch of both spacecraft with an ARIANE V in late 2017/early 2018 and an arrival at Mercury in 2024. From their dedicated orbits the two spacecraft will be studying the planet and its environment. The MPO scientific payload comprises eleven instruments/instrument packages; the MMO scientific payload consists of five instruments/instrument packages. Together, the scientific payload of both spacecraft will perform measurements to find clues to the origin and evolution of a planet close to its parent star. The MPO on BepiColombo will focus on a global characterization of Mercury through the investigation of its interior, surface, exosphere and magnetosphere. In addition, it will be testing Einstein's theory of general relativity. The MMO provided by JAXA focuses on investigating the wave and particle environment of the planet from an eccentric orbit. Together, the scientific payload of both spacecraft will provide the detailed information necessary to understand the process of planetary formation and evolution in the hottest part of the proto-planetary nebula as well as the similarities and differences between the magnetospheres of Mercury and the Earth. All scientific instruments have been integrated into the spacecraft and both spacecraft are now under final acceptance testing.

PVOL: The Planetary Virtual Observatory & Laboratory. An online database of the Outer Planets images.

NASA Astrophysics Data System (ADS)

Morgado, A.; Sánchez-Lavega, A.; Rojas, J. F.; Hueso, R.

2005-08-01

The collaboration between amateurs astronomers and the professional community has been fruitful on many areas of astronomy. The development of the Internet has allowed a better than ever capability of sharing information worldwide and access to other observers data. For many years now the International Jupiter Watch (IJW) Atmospheric discipline has coordinated observational efforts for long-term studies of the atmosphere of Jupiter. The International Outer Planets Watch (IOPW) has extended its labours to the four Outer Planets. Here we present the Planetary Virtual Observatory & Laboratory (PVOL), a website database where we integer IJW and IOPW images. At PVOL observers can submit their data and professionals can search for images under a wide variety of useful criteria such as date and time, filters used, observer, or central meridian longitude. PVOL is aimed to grow as an organized easy to use database of amateur images of the Outer Planets. The PVOL web address is located at http://www.pvol.ehu.es/ and coexists with the traditional IOPW site: http://www.ehu.es/iopw/ Acknowledgements: This work has been funded by Spanish MCYT PNAYA2003-03216, fondos FEDER and Grupos UPV 15946/2004. R. Hueso acknowledges a post-doc fellowship from Gobierno Vasco.

The International Outer Planets Watch atmospheres node database of giant-planet images

NASA Astrophysics Data System (ADS)

Hueso, R.; Legarreta, J.; Sánchez-Lavega, A.; Rojas, J. F.; Gómez-Forrellad, J. M.

2011-10-01

The Atmospheres Node of the International Outer Planets Watch (IOPW) is aimed to encourage the observations and study of the atmospheres of the Giant Planets. One of its main activities is to provide an interaction between the professional and amateur astronomical communities maintaining an online and fully searchable database of images of the giant planets obtained from amateur astronomers and available to both professional and amateurs [1]. The IOPW database contains about 13,000 image observations of Jupiter and Saturn obtained in the visible range with a few contributions of Uranus and Neptune. We describe the organization and structure of the database as posted in the Internet and in particular the PVOL software (Planetary Virtual Observatory & Laboratory) designed to manage the site and based in concepts from Virtual Observatory projects.

Photo by Voyager 1 (JPL) The spacecraft took this photo of the planet Jupiter on Jan 24, while still

NASA Technical Reports Server (NTRS)

1979-01-01

Photo by Voyager 1 (JPL) The spacecraft took this photo of the planet Jupiter on Jan 24, while still more than 25 million miles (40 million kilometers) away. As the spacecraft draws closer to the planet (about 1 million kilometers a day) more details are emergng in the turbulent clouds. The Great Red Spot shows prominently below center, surrounded by what scientists call a remarkably complex region of the giant planet's atmosphere. An elongated yellow cloud within the Great Red Spot is swirling around the spot's interior boundary in a counterclockwise direction with a period of a little less than six days, confirming the whirlpool-like circulation that astronomers have suspected from ground-based photographs. Ganymede, Jupiter's largest satellite, can be seen to the lower left of the planet. Ganymede is a planet-sized body larger than Mercury. This color photo was assembled at Jet Propulsion Laboratory's Image Processing Lab from there black and white images taken through filters. The Voyagers are managed for NASA's Office of Space Science by Jet Propulsion Laboratory. (ref: P-20945C Mission Image 1-9)

Ceres' Global Cryosphere

NASA Astrophysics Data System (ADS)

Sizemore, H. G.; Prettyman, T. H.; De Sanctis, M. C.; Schmidt, B. E.; Hughson, K.; Chilton, H.; Castillo, J. C.; Platz, T.; Schorghofer, N.; Bland, M. T.; Sori, M.; Buczkowski, D.; Byrne, S.; Landis, M. E.; Fu, R.; Ermakov, A.; Raymond, C. A.; Schwartz, S. J.

2017-12-01

Prior to the arrival of the Dawn spacecraft at Ceres, the dwarf planet was anticipated to have a deep global cryosphere protected by a thin silicate lag. Gravity science along with data collected by Dawn's Framing Camera (FC), Gamma Ray and Neutron Detector (GRaND), and Visible and Infrared Mapping Spectrometer (VIR-MS) during the primary mission at Ceres have confirmed the existence of a global, silicate-rich cryosphere, and suggest the existence of deeper ice, brine, or mud layers. As such, Ceres' surface morphology has characteristics in common with both Mars and the small icy bodies of the outer solar system. We will summarize the evidence for the existence and global extent of the Cerean cryosphere. We will also discuss the range of morphological features that have been linked to subsurface ice, and highlight outstanding science questions.

Highly integrated Pluto payload system (HIPPS): a sciencecraft instrument for the Pluto mission

NASA Astrophysics Data System (ADS)

Stern, S. Alan; Slater, David C.; Gibson, William; Reitsema, Harold J.; Delamere, W. Alan; Jennings, Donald E.; Reuter, D. C.; Clarke, John T.; Porco, Carolyn C.; Shoemaker, Eugene M.; Spencer, John R.

1995-09-01

We describe the design concept for the highly integrated Pluto payload system (HIPPS): a highly integrated, low-cost, light-weight, low-power instrument payload designed to fly aboard the proposed NASA Pluto flyby spacecraft destined for the Pluto/Charon system. The HIPPS payload is designed to accomplish all of the Pluto flyby prime (IA) science objectives, except radio science, set forth by NASA's Outer Planets Science Working Group (OPSWG) and the Pluto Express Science Definition Team (SDT). HIPPS contains a complement of three instrument components within one common infrastructure; these are: (1) a visible/near UV CCD imaging camera; (2) an infrared spectrograph; and (3) an ultraviolet spectrograph. A detailed description of each instrument is presented along with how they will meet the IA science requirements.

Micrometeorite Impact Test of Flex Solar Array Coupon

NASA Technical Reports Server (NTRS)

Wright, K. H.; Schneider, T. A.; Vaughn, J. A.; Hoang, B.; Wong, F.; Gardiner, G.

2016-01-01

Spacecraft with solar arrays operate throughout the near earth environment and are planned for outer planet missions. An often overlooked test condition for solar arrays that is applicable to these missions is micrometeoroid impacts and possibly electrostatic discharge (ESD) events resulting from these impacts. NASA Marshall Space Flight Center (MSFC) is partnering with Space Systems/Loral, LLC (SSL) to examine the results of simulated micrometeoroid impacts on the electrical performance of an advanced, lightweight flexible solar array design. The test is performed at MSFC's Micro Light Gas Gun Facility with SSL-provided coupons. Multiple impacts were induced at various locations on a powered test coupon under different string voltage (0V-150V) and string current (1.1A - 1.65A) conditions. The setup, checkout, and results from the impact testing are discussed.

Under Jupiter's Cloud Tops

NASA Image and Video Library

2017-05-25

NASA's Juno spacecraft carries an instrument called the Microwave Radiometer, which examines Jupiter's atmosphere beneath the planet's cloud tops. This image shows the instrument's view of the outer part of Jupiter's atmosphere. Before Juno began using this instrument, scientists expected the atmosphere to be uniform at depths greater than 60 miles (100 kilometers). But with the Microwave Radiometer, scientists have discovered that the atmosphere has variations down to at least 220 miles (350 kilometers), as deep as the instrument can see. In the cut-out image to the right, orange signifies high ammonia abundance and blue signifies low ammonia abundance. Jupiter appears to have a band around its equator high in ammonia abundance, with a column shown in orange. This is contrary to scientists' expectations that ammonia would be uniformly mixed. https://photojournal.jpl.nasa.gov/catalog/PIA21642

Methods for utilizing maximum power from a solar array

NASA Technical Reports Server (NTRS)

Decker, D. K.

1972-01-01

A preliminary study of maximum power utilization methods was performed for an outer planet spacecraft using an ion thruster propulsion system and a solar array as the primary energy source. The problems which arise from operating the array at or near the maximum power point of its 1-V characteristic are discussed. Two closed loop system configurations which use extremum regulators to track the array's maximum power point are presented. Three open loop systems are presented that either: (1) measure the maximum power of each array section and compute the total array power, (2) utilize a reference array to predict the characteristics of the solar array, or (3) utilize impedance measurements to predict the maximum power utilization. The advantages and disadvantages of each system are discussed and recommendations for further development are made.

Biology on the outer planets. [life possibility in atmospheres and moons

NASA Technical Reports Server (NTRS)

Young, R. S.; Macelroy, R. D.

1976-01-01

A brief review is given of information on the structure and composition of the outer planets and the organic reactions that may be occurring on them. The possibility of life arising or surviving in the atmospheres of these planets is considered, and the problem of contamination during future unmanned missions is assessed. Atmospheric models or available atmospheric data are reviewed for Jupiter, Saturn, Uranus, Neptune, Pluto, the Galilean satellites, and Titan. The presence of biologically interesting gases on Jupiter and Saturn is discussed, requirements for life on Jupiter are summarized, and possible sources of biological energy are examined. Proposals are made for protecting these planets and satellites from biological contamination by spacecraftborne terrestrial organisms.

Samara Probe For Remote Imaging

NASA Technical Reports Server (NTRS)

Burke, James D.

1989-01-01

Imaging probe descends through atmosphere of planet, obtaining images of ground surface as it travels. Released from aircraft over Earth or from spacecraft over another planet. Body and single wing shaped like samara - winged seed like those of maple trees. Rotates as descends, providing panoramic view of terrain below. Radio image obtained by video camera to aircraft or spacecraft overhead.

Retrograde and Direct Powered Aero-Gravity-Assist Trajectories around Mars

NASA Astrophysics Data System (ADS)

Murcia, J. O.; Prado, A. F. B. A.; Gomes, V. M.

2018-04-01

A Gravity-Assist maneuver is used to reduce fuel consumption and/or trip times in interplanetary missions. It is based in a close approach of a spacecraft to a celestial body. Missions like Voyager and Ulysses used this concept. The present paper performs a study of a maneuver that combines three effects: the gravity of the planet, the application of an impulsive maneuver when the spacecraft is passing by the periapsis and the effects of the atmosphere of the planet. Direct and retrograde trajectories are considered, with particular attention to the differences due to the higher relative velocity between the spacecraft and the atmosphere, which increases the effects of the atmosphere. The planet Mars is used for the numerical examples.

Testing giant planet formation in the transitional disk of SAO 206462 using deep VLT/SPHERE imaging

NASA Astrophysics Data System (ADS)

Maire, A.-L.; Stolker, T.; Messina, S.; Müller, A.; Biller, B. A.; Currie, T.; Dominik, C.; Grady, C. A.; Boccaletti, A.; Bonnefoy, M.; Chauvin, G.; Galicher, R.; Millward, M.; Pohl, A.; Brandner, W.; Henning, T.; Lagrange, A.-M.; Langlois, M.; Meyer, M. R.; Quanz, S. P.; Vigan, A.; Zurlo, A.; van Boekel, R.; Buenzli, E.; Buey, T.; Desidera, S.; Feldt, M.; Fusco, T.; Ginski, C.; Giro, E.; Gratton, R.; Hubin, N.; Lannier, J.; Le Mignant, D.; Mesa, D.; Peretti, S.; Perrot, C.; Ramos, J. R.; Salter, G.; Samland, M.; Sissa, E.; Stadler, E.; Thalmann, C.; Udry, S.; Weber, L.

2017-05-01

Context. The SAO 206462 (HD 135344B) disk is one of the few known transitional disks showing asymmetric features in scattered light and thermal emission. Near-infrared scattered-light images revealed two bright outer spiral arms and an inner cavity depleted in dust. Giant protoplanets have been proposed to account for the disk morphology. Aims: We aim to search for giant planets responsible for the disk features and, in the case of non-detection, to constrain recent planet predictions using the data detection limits. Methods: We obtained new high-contrast and high-resolution total intensity images of the target spanning the Y to the K bands (0.95-2.3 μm) using the VLT/SPHERE near-infrared camera and integral field spectrometer. Results: The spiral arms and the outer cavity edge are revealed at high resolutions and sensitivities without the need for aggressive image post-processing techniques, which introduce photometric biases. We do not detect any close-in companions. For the derivation of the detection limits on putative giant planets embedded in the disk, we show that the knowledge of the disk aspect ratio and viscosity is critical for the estimation of the attenuation of a planet signal by the protoplanetary dust because of the gaps that these putative planets may open. Given assumptions on these parameters, the mass limits can vary from 2-5 to 4-7 Jupiter masses at separations beyond the disk spiral arms. The SPHERE detection limits are more stringent than those derived from archival NaCo/L' data and provide new constraints on a few recent predictions of massive planets (4-15 MJ) based on the spiral density wave theory. The SPHERE and ALMA data do not favor the hypotheses on massive giant planets in the outer disk (beyond 0.6''). There could still be low-mass planets in the outer disk and/or planets inside the cavity. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programmes 095.C-0298 and 090.C-0443.

A charging model for three-axis stabilized spacecraft

NASA Technical Reports Server (NTRS)

Massaro, M. J.; Green, T.; Ling, D.

1977-01-01

A charging model was developed for geosynchronous, three-axis stabilized spacecraft when under the influence of a geomagnetic substorm. The differential charging potentials between the thermally coated or blanketed outer surfaces and metallic structure of a spacecraft were determined when the spacecraft was immersed in a dense plasma cloud of energetic particles. The spacecraft-to-environment interaction was determined by representing the charged particle environment by equivalent current source forcing functions and by representing the spacecraft by its electrically equivalent circuit with respect to the plasma charging phenomenon. The charging model included a sun/earth/spacecraft orbit model that simulated the sum illumination conditions of the spacecraft outer surfaces throughout the orbital flight on a diurnal as well as a seasonal basis. Transient and steady-state numerical results for a three-axis stabilized spacecraft are presented.

MECHANISM FOR EXCITING PLANETARY INCLINATION AND ECCENTRICITY THROUGH A RESIDUAL GAS DISK

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen Yuanyuan; Liu Huigen; Zhao Gang

2013-05-20

According to the theory of Kozai resonance, the initial mutual inclination between a small body and a massive planet in an outer circular orbit is as high as {approx}39. Degree-Sign 2 for pumping the eccentricity of the inner small body. Here we show that with the presence of a residual gas disk outside two planetary orbits, the inclination can be reduced to as low as a few degrees. The presence of the disk changes the nodal precession rates and directions of the planet orbits. At the place where the two planets achieve the same nodal processing rate, vertical secular resonancemore » (VSR) occurs so that the mutual inclination of the two planets will be excited, which might further trigger the Kozai resonance between the two planets. However, in order to pump an inner Jupiter-like planet, the conditions required for the disk and the outer planet are relatively strict. We develop a set of evolution equations, which can fit the N-body simulation quite well but can be integrated within a much shorter time. By scanning the parameter spaces using the evolution equations, we find that a massive planet (10 M{sub J} ) at 30 AU with an inclination of 6 Degree-Sign to a massive disk (50 M{sub J} ) can finally enter the Kozai resonance with an inner Jupiter around the snowline. An inclination of 20 Degree-Sign of the outer planet to the disk is required for flipping the inner one to a retrograde orbit. In multiple planet systems, the mechanism can happen between two nonadjacent planets or can inspire a chain reaction among more than two planets. This mechanism could be the source of the observed giant planets in moderate eccentric and inclined orbits, or hot Jupiters in close-in, retrograde orbits after tidal damping.« less

Outer planet probe navigation. [considering Pioneer space missions

NASA Technical Reports Server (NTRS)

Friedman, L.

1974-01-01

A series of navigation studies in conjunction with outer planet Pioneer missions are reformed to determine navigation requirements and measurement systems in order to target probes. Some particular cases are established where optical navigation is important and some cases where radio alone navigation is suffucient. Considered are a direct Saturn mission, a Saturn Uranus mission, a Jupiter Uranus mission, and a Titan probe mission.

Fluxgate magnetometers for outer planets exploration

NASA Technical Reports Server (NTRS)

Acuna, M. H.

1974-01-01

The exploration of the interplanetary medium and the magnetospheres of the outer planets requires the implementation of magnetic field measuring instrumentation with wide dynamic range, high stability, and reliability. The fluxgate magnetometers developed for the Pioneer 11 and Mariner-Jupiter-Saturn missions are presented. These instruments cover the range of .01 nT to 2 million nT with optimum performance characteristics and low power consumption.

Ten bar probe technical summary. [feasibility of outer planet common atmospheric probe

NASA Technical Reports Server (NTRS)

Ellis, T. R.

1974-01-01

The feasibility of an outer planet common atmospheric probe is studied with emphasis on entry heating rates and improved ephemeris. It is concluded that a common probe design is possible except for Jupiter; the basic technology exists except for Jupiter heat shielding. A Mariner class bus provides for better bus science and probe bus communications than a Pioneer class bus.

Operational Planetary Space Weather Services for the Europlanet 2020 Research Infrastructure

NASA Astrophysics Data System (ADS)

André, Nicolas; Grande, Manuel

2017-04-01

Under Horizon 2020, the Europlanet 2020 Research Infrastructure (EPN2020-RI, http://www.europlanet-2020-ri.eu) includes an entirely new Virtual Access Service, "Planetary Space Weather Services" (PSWS) that will extend the concepts of space weather and space situational awareness to other planets in our Solar System and in particular to spacecraft that voyage through it. PSWS will provide at the end of 2017 12 services distributed over 4 different service domains - 1) Prediction, 2) Detection, 3) Modelling, 4) Alerts. These services include 1.1) A 1D MHD solar wind prediction tool, 1.2) Extensions of a Propagation Tool, 1.3) A meteor showers prediction tool, 1.4) A cometary tail crossing prediction tool, 2.1) Detection of lunar impacts, 2.2) Detection of giant planet fireballs, 2.3) Detection of cometary tail events, 3.1) A Transplanet model of magnetosphere-ionosphere coupling, 3.2) A model of the Mars radiation environment, 3.3.) A model of giant planet magnetodisc, 3.4) A model of Jupiter's thermosphere, 4) A VO-event based alert system. We will detail in the present paper some of these services with a particular emphasis on those already operational at the time of the presentation (1.1, 1.2, 1.3, 2.2, 3.1, 4). The proposed Planetary Space Weather Services will be accessible to the research community, amateur astronomers as well as to industrial partners planning for space missions dedicated in particular to the following key planetary environments: Mars, in support of ESA's ExoMars missions; comets, building on the success of the ESA Rosetta mission; and outer planets, in preparation for the ESA JUpiter ICy moon Explorer (JUICE). These services will also be augmented by the future Solar Orbiter and BepiColombo observations. This new facility will not only have an impact on planetary space missions but will also allow the hardness of spacecraft and their components to be evaluated under variety of known conditions, particularly radiation conditions, extending their knownflight-worthiness for terrestrial applications. Europlanet 2020 RI has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 654208.

Spacecraft Solar Sails Containing Electrodynamic Tethers

NASA Technical Reports Server (NTRS)

Johnson, Les; Matloff, Greg

2005-01-01

A report discusses a proposal to use large, lightweight solar sails embedded with electrodynamic tethers (essentially, networks of wires) to (1) propel robotic spacecraft to distant planets, then (2) exploit the planetary magnetic fields to capture the spacecraft into orbits around the planets. The purpose of the proposal is, of course, to make it possible to undertake long interplanetary missions without incurring the large cost and weight penalties of conventional rocket-type propulsion systems. Through transfer of momentum from reflected solar photons, a sail would generate thrust outward from the Sun. Upon arrival in the vicinity of a planet, the electrodynamic tethers would be put to use: Motion of the spacecraft across the planetary magnetic field would induce electric currents in the tether wires, giving rise to an electromagnetic drag force that would be exploited to brake the spacecraft for capture into orbit. The sail with embedded tethers would be made to spin to provide stability during capture. Depending upon the requirements of a particular application, it could be necessary to extend the tether to a diameter greater than that of the sail.

Characterizing Cold Giant Planets in Reflected Light: Lessons from 50 Years of Outer Solar System Exploration and Observation

NASA Technical Reports Server (NTRS)

Marley, Mark Scott; Hammel, Heidi

2014-01-01

A space based coronagraph, whether as part of the WFIRST/AFTA mission or on a dedicated space telescope such as Exo-C or -S, will be able to obtain photometry and spectra of multiple gas giant planets around nearby stars, including many known from radial velocity detections. Such observations will constrain the masses, atmospheric compositions, clouds, and photochemistry of these worlds. Giant planet albedo models, such as those of Cahoy et al. (2010) and Lewis et al. (this meeting), will be crucial for mission planning and interpreting the data. However it is equally important that insights gleaned from decades of solar system imaging and spectroscopy of giant planets be leveraged to optimize both instrument design and data interpretation. To illustrate these points we will draw on examples from solar system observations, by both HST and ground based telescopes, as well as by Voyager, Galileo, and Cassini, to demonstrate the importance clouds, photochemical hazes, and various molecular absorbers play in sculpting the light scattered by solar system giant planets. We will demonstrate how measurements of the relative depths of multiple methane absorption bands of varying strengths have been key to disentangling the competing effects of gas column abundances, variations in cloud height and opacity, and scattering by high altitude photochemical hazes. We will highlight both the successes, such as the accurate remote determination of the atmospheric methane abundance of Jupiter, and a few failures from these types of observations. These lessons provide insights into technical issues facing spacecraft designers, from the selection of the most valuable camera filters to carry to the required capabilities of the flight spectrometer, as well as mission design questions such as choosing the most favorable phase angles for atmospheric characterization.

Theories of the origin and evolution of the giant planets

NASA Technical Reports Server (NTRS)

Pollack, J. B.; Bodenheimer, P.

1989-01-01

Following the accretion of solids and gases in the solar nebula, the giant planets contracted to their present sizes over the age of the solar system. It is presently hypothesized that this contraction was rapid, but not hydrodynamic; at a later stage, a nebular disk out of which the regular satellites formed may have been spun out of the outer envelope of the contracting giant planets due to a combination of total angular momentum conservation and the outward transfer of specific angular momentum in the envelope. If these hypotheses are true, the composition of the irregular satellites directly reflects the composition of planetesimals from which the giant planets formed, while the composition of the regular satellites is indicative of the composition of the less volatile components of the outer envelopes of the giant planets.

The Voyager flights to Jupiter and Saturn

NASA Technical Reports Server (NTRS)

1982-01-01

The results of the mini-Grand Tour to Jupiter and Saturn by the Voyager 1 and 2 spacecraft are highlighted. Features of the spacecraft are depicted including the 11 instruments designed to probe the planets and their magnetic environments, the rings of Saturn, the fleets of satellites escorting the planets, and the interplanetary medium. Major scientific discoveries relating to these phenomena are summarized.

The Elephant in the Room: Effects of Distant, Massive Companions on Planetary System Architectures

NASA Astrophysics Data System (ADS)

Knutson, Heather

2016-06-01

Over the past two decades ongoing radial velocity and transit surveys have been astoundingly successful in detecting thousands of new planetary systems around nearby stars. These systems include apparently single gas giant planets on short period orbits, closely packed systems of up to 5-6 “super-Earths”, and relatively empty systems with either one or no small planets interior to 0.5 AU. Despite our success in cataloguing the diverse properties of these systems, we are still struggling to develop narratives that can explain their apparently divergent formation and migration histories. This is in large part due to our lack of knowledge about the potential presence of massive outer companions in these systems, which can play a pivotal role in the shaping the final properties of the inner planets. In my talk I will discuss current efforts to complete the census for known planetary systems by searching for outer gas giant planets with long term radial velocity monitoring and wide separation stellar companions with high contrast imaging and spectroscopy. I will then demonstrate how statistical constraints on this population of outer companions can be used to test current theories for planet formation and migration.

Progress in four-beam nulling: results from the Terrestrial Planet Finder planet detection testbed

NASA Technical Reports Server (NTRS)

Martin, Stefan

2006-01-01

The Terrestrial Planet Finder Interferometer (TPF-I) is a large space telescope consisting of four 4 meter diameter telescopes flying in formation in space together with a fifth beam combiner spacecraft.

Progress in four-beam nulling: results from the Terrestrial Planet Finder Planet Detection Testbed

NASA Technical Reports Server (NTRS)

Martin, Stefan

2006-01-01

The Terrestrial Planet Finder Interferometer (TPF-I) is a large space telescope consisting of four 4 meter diameter telescopes flying in formation in space together with a fifth beam combiner spacecraft.

Nonrelativistic Contribution to Mercury's Perihelion Precession.

ERIC Educational Resources Information Center

Price, Michael P.; Rush, William F.

1979-01-01

Presents a calculation of the precession of the perihelion of Mercury due to the perturbations from the outer planets. The time-average effect of each planet is calculated by replacing that planet with a ring of linear mass density equal to the mass of the planet divided by the circumference of its orbit. (Author/GA)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bromley, Benjamin C.; Kenyon, Scott J., E-mail: bromley@physics.utah.edu, E-mail: skenyon@cfa.harvard.edu

Correlations in the orbits of several minor planets in the outer solar system suggest the presence of a remote, massive Planet Nine. With at least 10 times the mass of the Earth and a perihelion well beyond 100 au, Planet Nine poses a challenge to planet formation theory. Here we expand on a scenario in which the planet formed closer to the Sun and was gravitationally scattered by Jupiter or Saturn onto a very eccentric orbit in an extended gaseous disk. Dynamical friction with the gas then allowed the planet to settle in the outer solar system. We explore thismore » possibility with a set of numerical simulations. Depending on how the gas disk evolves, scattered super-Earths or small gas giants settle on a range of orbits, with perihelion distances as large as 300 au. Massive disks that clear from the inside out on million-year timescales yield orbits that allow a super-Earth or gas giant to shepherd the minor planets as observed. A massive planet can achieve a similar orbit in a persistent, low-mass disk over the lifetime of the solar system.« less

Vega's hot dust from icy planetesimals scattered inwards by an outward-migrating planetary system

NASA Astrophysics Data System (ADS)

Raymond, Sean N.; Bonsor, Amy

2014-07-01

Vega has been shown to host multiple dust populations, including both hot exozodiacal dust at sub-au radii and a cold debris disc extending beyond 100 au. We use dynamical simulations to show how Vega's hot dust can be created by long-range gravitational scattering of planetesimals from its cold outer regions. Planetesimals are scattered progressively inwards by a system of 5-7 planets from 30 to 60 au to very close-in. In successful simulations, the outermost planets are typically Neptune mass. The back-reaction of planetesimal scattering causes these planets to migrate outwards and continually interact with fresh planetesimals, replenishing the source of scattered bodies. The most favourable cases for producing Vega's exozodi have negative radial mass gradients, with sub-Saturn- to Jupiter-mass inner planets at 5-10 au and outer planets of 2.5 - 20 M⊕ . The mechanism fails if a Jupiter-sized planet exists beyond ˜15 au because the planet preferentially ejects planetesimals before they can reach the inner system. Direct-imaging planet searches can therefore directly test this mechanism.

Chairmanship of the Neptune/Pluto outer planets science working group

NASA Astrophysics Data System (ADS)

Stern, S. Alan

1993-11-01

The Outer Planets Science Working Group (OPSWG) is the NASA Solar System Exploration Division (SSED) scientific steering committee for the Outer Solar System missions. OPSWG consists of 19 members and is chaired by Dr. S. Alan Stern. This proposal summarizes the FY93 activities of OPSWG, describes a set of objectives for OPSWG in FY94, and outlines the SWG's activities for FY95. As chair of OPSWG, Dr. Stern will be responsible for: organizing priorities, setting agendas, conducting meetings of the Outer Planets SWG; reporting the results of OPSWG's work to SSED; supporting those activities relating to OPSWG work, such as briefings to the SSES, COMPLEX, and OSS; supporting the JPL/SAIC Pluto study team; and other tasks requested by SSED. As the Scientific Working Group (SWG) for Jupiter and the planets beyond, OPSWG is the SSED SWG chartered to study and develop mission plans for all missions to the giant planets, Pluto, and other distant objects in the remote outer solar system. In that role, OPSWG is responsible for: defining and prioritizing scientific objectives for missions to these bodies; defining and documenting the scientific goals and rationale behind such missions; defining and prioritizing the datasets to be obtained in these missions; defining and prioritizing measurement objectives for these missions; defining and documenting the scientific rationale for strawman instrument payloads; defining and prioritizing the scientific requirements for orbital tour and flyby encounter trajectories; defining cruise science opportunities plan; providing technical feedback to JPL and SSED on the scientific capabilities of engineering studies for these missions; providing documentation to SSED concerning the scientific goals, objectives, and rationale for the mission; interfacing with other SSED and OSS committees at the request of SSED's Director or those committee chairs; providing input to SSED concerning the structure and content of the Announcement of Opportunity for payload and scientific team selection for such missions; and providing other technical or programmatic inputs concerning outer solar system missions at the request of the Director of SSED.

Chairmanship of the Neptune/Pluto outer planets science working group

NASA Technical Reports Server (NTRS)

Stern, S. Alan

1993-01-01

The Outer Planets Science Working Group (OPSWG) is the NASA Solar System Exploration Division (SSED) scientific steering committee for the Outer Solar System missions. OPSWG consists of 19 members and is chaired by Dr. S. Alan Stern. This proposal summarizes the FY93 activities of OPSWG, describes a set of objectives for OPSWG in FY94, and outlines the SWG's activities for FY95. As chair of OPSWG, Dr. Stern will be responsible for: organizing priorities, setting agendas, conducting meetings of the Outer Planets SWG; reporting the results of OPSWG's work to SSED; supporting those activities relating to OPSWG work, such as briefings to the SSES, COMPLEX, and OSS; supporting the JPL/SAIC Pluto study team; and other tasks requested by SSED. As the Scientific Working Group (SWG) for Jupiter and the planets beyond, OPSWG is the SSED SWG chartered to study and develop mission plans for all missions to the giant planets, Pluto, and other distant objects in the remote outer solar system. In that role, OPSWG is responsible for: defining and prioritizing scientific objectives for missions to these bodies; defining and documenting the scientific goals and rationale behind such missions; defining and prioritizing the datasets to be obtained in these missions; defining and prioritizing measurement objectives for these missions; defining and documenting the scientific rationale for strawman instrument payloads; defining and prioritizing the scientific requirements for orbital tour and flyby encounter trajectories; defining cruise science opportunities plan; providing technical feedback to JPL and SSED on the scientific capabilities of engineering studies for these missions; providing documentation to SSED concerning the scientific goals, objectives, and rationale for the mission; interfacing with other SSED and OSS committees at the request of SSED's Director or those committee chairs; providing input to SSED concerning the structure and content of the Announcement of Opportunity for payload and scientific team selection for such missions; and providing other technical or programmatic inputs concerning outer solar system missions at the request of the Director of SSED.

Electrodynamic Tether Propulsion and Power Generation at Jupiter

NASA Technical Reports Server (NTRS)

Gallagher, D. L.; Johnson, L.; Moore, J.; Bagenal, F.

1998-01-01

The results of a study performed to evaluate the feasibility and merits of using an electrodynamic tether for propulsion and power generation for a spacecraft in the Jovian system are presented. The environment of the Jovian system has properties which are particularly favorable for utilization of an electrodynamic tether. Specifically, the planet has a strong magnetic field and the mass of the planet dictates high orbital velocities which, when combined with the planet's rapid rotation rate, can produce very large relative velocities between the magnetic field and the spacecraft. In a circular orbit close to the planet, tether propulsive forces are found to be as high as 50 N and power levels as high as 1 MW.

Straw in the B Ring Edge

NASA Image and Video Library

2017-01-30

This image shows a region in Saturn's outer B ring. NASA's Cassini spacecraft viewed this area at a level of detail twice as high as it had ever been observed before. The view here is of the outer edge of the B ring, at left, which is perturbed by the most powerful gravitational resonance in the rings: the "2:1 resonance" with the icy moon Mimas. This means that, for every single orbit of Mimas, the ring particles at this specific distance from Saturn orbit the planet twice. This results in a regular tugging force that perturbs the particles in this location. A lot of structure is visible in the zone near the edge on the left. This is likely due to some combination of the gravity of embedded objects too small to see, or temporary clumping triggered by the action of the resonance itself. Scientists informally refer to this type of structure as "straw." This image was taken using a fairly long exposure, causing the embedded clumps to smear into streaks as they moved in their orbits. Later Cassini orbits will bring shorter exposures of the same region, which will give researchers a better idea of what these clumps look like. But in this case, the smearing does help provide a clearer idea of how the clumps are moving. This image is a lightly processed version, with minimal enhancement; this version preserves all original details present in the image. Another other version (Figure 1) has been processed to remove the small bright blemishes due to cosmic rays and charged particle radiation near the planet -- a more aesthetically pleasing image, but with a slight softening of the finest details. The image was taken in visible light with the Cassini spacecraft wide-angle camera on Dec. 18, 2016. The view was obtained at a distance of approximately 32,000 miles (52,000 kilometers) from the rings and looks toward the unilluminated side of the rings. Image scale is about a quarter-mile (360 meters) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA21057

The Mars Climate Orbiter at Launch Complex 17A, CCAS

NASA Technical Reports Server (NTRS)

1998-01-01

At Launch Complex 17A, Cape Canaveral Air Station, workers place aside a piece of the canister surrounding the Mars Climate Orbiter. Targeted for liftoff on Dec. 10, 1998, aboard a Boeing Delta II (7425) rocket, the orbiter will be the first spacecraft to be launched in the pair of Mars '98 missions. After its arrival at the red planet, the Mars Climate Orbiter will be used primarily to support its companion Mars Polar Lander spacecraft, scheduled for launch on Jan. 3, 1999. The orbiter will then monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year, the equivalent of about two Earth years. The spacecraft will observe the appearance and movement of atmospheric dust and water vapor, and characterize seasonal changes on the planet's surface.

The Mars Climate Orbiter at Launch Complex 17A, CCAS

NASA Technical Reports Server (NTRS)

1998-01-01

At Launch Complex 17A, Cape Canaveral Air Station, workers remove the canister surrounding the Mars Climate Orbiter. Targeted for liftoff on Dec. 10, 1998, aboard a Boeing Delta II (7425) rocket, the orbiter will be the first spacecraft to be launched in the pair of Mars '98 missions. After its arrival at the red planet, the Mars Climate Orbiter will be used primarily to support its companion Mars Polar Lander spacecraft, scheduled for launch on Jan. 3, 1999. The orbiter will then monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year, the equivalent of about two Earth years. The spacecraft will observe the appearance and movement of atmospheric dust and water vapor, and characterize seasonal changes on the planet's surface.

KSC-98pc1813

NASA Image and Video Library

1998-12-01

KENNEDY SPACE CENTER, FLA. -- At Launch Complex 17A, Cape Canaveral Air Station, workers remove the canister surrounding the Mars Climate Orbiter. Targeted for liftoff on Dec. 10, 1998, aboard a Boeing Delta II (7425) rocket, the orbiter will be the first spacecraft to be launched in the pair of Mars '98 missions. After its arrival at the red planet, the Mars Climate Orbiter will be used primarily to support its companion Mars Polar Lander spacecraft, scheduled for launch on Jan. 3, 1999. The orbiter will then monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year, the equivalent of about two Earth years. The spacecraft will observe the appearance and movement of atmospheric dust and water vapor, and characterize seasonal changes on the planet's surface

KSC-98pc1814

NASA Image and Video Library

1998-12-04

KENNEDY SPACE CENTER, FLA. -- At Launch Complex 17A, Cape Canaveral Air Station, workers place aside a piece of the canister surrounding the Mars Climate Orbiter. Targeted for liftoff on Dec. 10, 1998, aboard a Boeing Delta II (7425) rocket, the orbiter will be the first spacecraft to be launched in the pair of Mars '98 missions. After its arrival at the red planet, the Mars Climate Orbiter will be used primarily to support its companion Mars Polar Lander spacecraft, scheduled for launch on Jan. 3, 1999. The orbiter will then monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year, the equivalent of about two Earth years. The spacecraft will observe the appearance and movement of atmospheric dust and water vapor, and characterize seasonal changes on the planet's surface

Missions to Venus

NASA Astrophysics Data System (ADS)

Titov, D. V.; Baines, K. H.; Basilevsky, A. T.; Chassefiere, E.; Chin, G.; Crisp, D.; Esposito, L. W.; Lebreton, J.-P.; Lellouch, E.; Moroz, V. I.; Nagy, A. F.; Owen, T. C.; Oyama, K.-I.; Russell, C. T.; Taylor, F. W.; Young, R. E.

2002-10-01

Venus has always been a fascinating objective for planetary studies. At the beginning of the space era Venus became one of the first targets for spacecraft missions. Our neighbour in the solar system and, in size, the twin sister of Earth, Venus was expected to be very similar to our planet. However, the first phase of Venus spacecraft exploration in 1962-1992 by the family of Soviet Venera and Vega spacecraft and US Mariner, Pioneer Venus, and Magellan missions discovered an entirely different, exotic world hidden behind a curtain of dense clouds. These studies gave us a basic knowledge of the conditions on the planet, but generated many more questions concerning the atmospheric composition, chemistry, structure, dynamics, surface-atmosphere interactions, atmospheric and geological evolution, and the plasma environment. Despite all of this exploration by more than 20 spacecraft, the "morning star" still remains a mysterious world. But for more than a decade Venus has been a "forgotten" planet with no new missions featuring in the plans of the world space agencies. Now we are witnessing the revival of interest in this planet: the Venus Orbiter mission is approved in Japan, Venus Express - a European orbiter mission - has successfully passed the selection procedure in ESA, and several Venus Discovery proposals are knocking at the doors of NASA. The paper presents an exciting story of Venus spacecraft exploration, summarizes open scientific problems, and builds a bridge to the future missions.

The solar system/interstellar medium connection - Gas phase abundances

NASA Technical Reports Server (NTRS)

Lutz, Barry L.

1987-01-01

Gas-phase abundances in the outer solar system are presented as diagnostics of the interstellar medium at the time of the solar system formation, some 4.55 billion years ago. Possible influences of the thermal and chemical histories of the primitive solar nebula and of the processes which led to the formation and evolution of the outer planets and comets on the elemental and molecular composition of the primordial matter are outlined. The major components of the atmospheres of the outer planets and of the comae of comets are identified, and the cosmogonical and cosmological implications are discussed.

Possible misinterpretation of lunar cratering record in Voyager team analyses of outer planet satellites

NASA Technical Reports Server (NTRS)

Hartmann, William K.

1991-01-01

While interpreting outer planetary satellites, the Voyager imaging team repeatedly referred to a lunar frontside highland calibration curve. It was assumed that it is unmodified and not in steady state equilibrium, but rather records all impacts that have occurred. It was also assumed that it records the size distribution of an early population of impactors, called Population I, evidence for which was found on various satellites. New evidence is reported that the Voyager team interpretation of this population is wrong, a conclusion that seriously affects the cratering histories reported for outer planet satellites.

Outer planet probe cost estimates: First impressions

NASA Technical Reports Server (NTRS)

Niehoff, J.

1974-01-01

An examination was made of early estimates of outer planetary atmospheric probe cost by comparing the estimates with past planetary projects. Of particular interest is identification of project elements which are likely cost drivers for future probe missions. Data are divided into two parts: first, the description of a cost model developed by SAI for the Planetary Programs Office of NASA, and second, use of this model and its data base to evaluate estimates of probe costs. Several observations are offered in conclusion regarding the credibility of current estimates and specific areas of the outer planet probe concept most vulnerable to cost escalation.

Rings Research in the Next Decade

NASA Astrophysics Data System (ADS)

Tiscareno, Matthew S.; Albers, N.; Brahic, A.; Brooks, S. M.; Burns, J. A.; Chavez, C.; Colwell, J. E.; Cuzzi, J. N.; de Pater, I.; Dones, L.; Durisen, R. H.; Filacchione, G.; Giuliatti Winter, S. M.; Gordon, M. K.; Graps, A.; Hamilton, D. P.; Hedman, M. M.; Horanyi, M.; Kempf, S.; Krueger, H.; Lewis, M. C.; Lissauer, J. J.; Murray, C. D.; Nicholson, P. D.; Olkin, C. B.; Pappalardo, R. T.; Salo, H.; Schmidt, J.; Showalter, M. R.; Spahn, F.; Spilker, L. J.; Srama, R.; Sremcevic, M.; Stewart, G. R.; Yanamandra-Fisher, P.

2009-12-01

The study of planetary ring systems is a key component of planetary science for several reasons: 1) The evolution and current states of planets and their satellites are affected in many ways by rings, while 2) conversely, properties of planets and moons and other solar system populations are revealed by their effects on rings; 3) highly structured and apparently delicate ring systems may be bellwethers, constraining various theories of the origin and evolution of their entire planetary system; and finally, 4) planetary rings provide an easily observable analogue to other astrophysical disk systems, enabling real "ground truth” results applicable to disks much more remote in space and/or time, including proto-planetary disks, circum-stellar disks, and even galaxies. Significant advances have been made in rings science in the past decade. The highest-priority rings research recommendations of the last Planetary Science Decadal Survey were to operate and extend the Cassini orbiter mission at Saturn; this has been done with tremendous success, accounting for much of the progress made on key science questions, as we will describe. Important progress in understanding the rings of Saturn and other planets has also come from Earth-based observational and theoretical work, again as prioritized by the last Decadal Survey. However, much important work remains to be done. At Saturn, the Cassini Solstice Mission must be brought to a successful completion. Priority should also be placed on sending spacecraft to Neptune and/or Uranus, now unvisited for more than 20 years. At Jupiter and Pluto, opportunities afforded by visiting spacecraft capable of studying rings should be exploited. On Earth, the need for continued research and analysis remains strong, including in-depth analysis of rings data already obtained, numerical and theoretical modeling work, laboratory analysis of materials and processes analogous to those found in the outer solar system, and continued Earth-based observations.

Proceedings: Outer Planet Probe Technology Workshop, summary volume

NASA Technical Reports Server (NTRS)

1974-01-01

A summary report and overview of the Outer Planet Probe Technology Conference are given. Summary data cover: (1) state of the art concerning mission definitions, probe requirements, systems, subsystems, and mission peculiar hardware, (2) mission and equipment trade-offs associated with Saturn/Uranus baseline configuration and the influence of Titan and Jupiter options on mission performance and costs, and (3) identification of critically required future R and D activities.

TPS for Outer Planets

NASA Technical Reports Server (NTRS)

Venkatapathy, Ethiraj; Ellerby, D.; Gage, P.; Gasch, M.; Hwang, H.; Prabhu, D.; Stackpoole, M.; Wercinski, Paul

2018-01-01

This invited talk will provide an assessment of the TPS needs for Outer Planet In-situ missions to destinations with atmosphere. The talk will outline the drivers for TPS from destination, science, mission architecture and entry environment. An assessment of the readiness of the TPS, both currently available and under development, for Saturn, Titan, Uranus and Neptune are provided. The challenges related to sustainability of the TPS for future missions are discussed.

Nuclear Electric Propulsion for Outer Space Missions

NASA Technical Reports Server (NTRS)

Barret, Chris

2003-01-01

Today we know of 66 moons in our very own Solar System, and many of these have atmospheres and oceans. In addition, the Hubble (optical) Space Telescope has helped us to discover a total of 100 extra-solar planets, i.e., planets going around other suns, including several solar systems. The Chandra (X-ray) Space Telescope has helped us to discover 33 Black Holes. There are some extremely fascinating things out there in our Universe to explore. In order to travel greater distances into our Universe, and to reach planetary bodies in our Solar System in much less time, new and innovative space propulsion systems must be developed. To this end NASA has created the Prometheus Program. When one considers space missions to the outer edges of our Solar System and far beyond, our Sun cannot be relied on to produce the required spacecraft (s/c) power. Solar energy diminishes as the square of the distance from the Sun. At Mars it is only 43% of that at Earth. At Jupiter, it falls off to only 3.6% of Earth's. By the time we get out to Pluto, solar energy is only .066% what it is on Earth. Therefore, beyond the orbit of Mars, it is not practical to depend on solar power for a s/c. However, the farther out we go the more power we need to heat the s/c and to transmit data back to Earth over the long distances. On Earth, knowledge is power. In the outer Solar System, power is knowledge. It is important that the public be made aware of the tremendous space benefits offered by Nuclear Electric Propulsion (NEP) and the minimal risk it poses to our environment. This paper presents an overview of the reasons for NEP systems, along with their basic components including the reactor, power conversion units (both static and dynamic), electric thrusters, and the launch safety of the NEP system.

Mars Observer trajectory and orbit design

NASA Technical Reports Server (NTRS)

Beerer, Joseph G.; Roncoli, Ralph B.

1991-01-01

The Mars Observer launch, interplanetary, Mars orbit insertion, and mapping orbit designs are described. The design objective is to enable a near-maximum spacecraft mass to be placed in orbit about Mars. This is accomplished by keeping spacecraft propellant requirements to a minimum, selecting a minimum acceptable launch period, equalizing the spacecraft velocity change requirement at the beginning and end of the launch period, and constraining the orbit insertion maneuvers to be coplanar. The mapping orbit design objective is to provide the opportunity for global observation of the planet by the science instruments while facilitating the spacecraft design. This is realized with a sun-synchronous near-polar orbit whose ground-track pattern covers the planet at progressively finer resolution.

Jet Propulsion Laboratory: Annual Report 2002

NASA Technical Reports Server (NTRS)

2003-01-01

The year 2002 brought advances on many fronts in our space exploration ventures. A new orbiter settled in at Mars and delivered tantalizing science results suggesting a vast store of water ice under the planet's surface, a discovery that may have profound consequences for exploring Mars. A long-lived spacecraft made its final fly-bys of Jupiter's moons, while another started its final approach toward Saturn and yet another flew by an asteroid on its way to a comet. A new ocean satellite began science observations, joined in Earth orbit by a pair of spacecraft measuring our home planets gravity field, as well as JPL instruments on NASA and Japanese satellites. A major new infrared observatory and a pair of Mars rovers were readied for launch. All told, JPL is now communicating with 14 spacecraft cast like gems across the velvet expanses of the solar system. It is a far cry from the early 1960's, when JPL engineers made prodigious efforts to get the first planetary explorers off the ground and into space - an achievement of which we were especially mindful this year, as 2002 marked the 40th anniversary of the first successful planetary mission, Mariner 2, which barely reached our closest planetary neighbor, Venus. Added to this anniversary were celebrations surrounding the 25th anniversaries of the launches of Voyagers 1 and 2, two remarkable spacecraft that are still flying and are actively probing the outer realms of the solar system. These events of the past and present provide an occasion for reflection on the remarkable era of exploration that we at the Jet Propulsion Laboratory are privileged to be a part of. As 2002 neared its end, the Laboratory had yet another reason for celebration, as a new five-year management contract between NASA and the California Institute of Technology was signed that calls for a closer working relationship with NASA and other NASA centers as a member of the 'One NASA' team. There is a strong emphasis on cost control and management, areas in which we can improve, enabling us to become more competitive. This new agreement again confirms NASA's trust and faith in Caltech and JPL, in which we should all take great pride. If the history of JPL were a book, we are on the verge of turning the page to one that promises to be one of the most exciting and busiest chapters in JPL's history. In 2003 and 2004, we will launch 11 spacecraft or major payloads. We will land two rovers on Mars; put a spacecraft in orbit around Saturn, deliver a probe to the surface of its largest moon, Titan, and map Titan's surface withimaging radar; send a spacecraft past a comet collecting samples from its tail, while another one is launched toward a comet impact; bring a capsule back to Earth with the first samples ever collected beyond the orbit of the Moon; map the skies in the ultraviolet as well as the infrared spectrum to unprecedented accuracy; and continue the mapping of ocean topography and winds on our home planet, Earth.

Space Science in Action: Planets and the Solar System [Videotape].

ERIC Educational Resources Information Center

1999

This videotape recording teaches students about the key characteristics of each planet, the differences between inner and outer planets, and which planets have their own moons. Students look at how remote-control rovers are designed to explore other surfaces in the solar system. A hands-on activity demonstrates how gravity keeps all the members of…

Geodesy at Mercury with MESSENGER

NASA Technical Reports Server (NTRS)

Smith, David E.; Zuber, Maria t.; Peale, Stanley J.; Phillips, Roger J.; Solomon, Sean C.

2006-01-01

In 2011 the MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft will enter Mercury orbit and begin the mapping phase of the mission. As part of its science objectives the MESSENGER mission will determine the shape and gravity field of Mercury. These observations will enable the topography and the crustal thickness to be derived for the planet and will determine the small libration of the planet about its axis, the latter critical to constraining the state of the core. These measurements require very precise positioning of the MESSENGER spacecraft in its eccentric orbit, which has a periapsis altitude as low as 200 km, an apoapsis altitude near 15,000 km, and a closest approach to the surface varying from latitude 60 to about 70 N. The X-band tracking of MESSENGER and the laser altimetry are the primary data that will be used to measure the planetary shape and gravity field. The laser altimeter, which has an expected range of 1000 to 1200 km, is expected to provide significant data only over the northern hemisphere because of MESSENGER's eccentric orbit. For the southern hemisphere, radio occultation measurements obtained as the spacecraft passes behind the planet as seen from Earth and images obtained with the imaging system will be used to provide the long-wavelength shape of the planet. Gravity, derived from the tracking data, will also have greater resolution in the northern hemisphere, but full global models for both topography and gravity will be obtained at low harmonic order and degree. The limiting factor for both gravity and topography is expected to be knowledge of the spacecraft location. Present estimations are that in a combined tracking, altimetry, and occultation solution the spacecraft position uncertainty is likely to be of order 10 m. This accuracy should be adequate for establishing an initial geodetic coordinate system for Mercury that will enable positioning of imaged features on the surface, determination of the planet's obliquity, and detection of the librational motion of the planet about its axis.

Searching for organics on the dwarf planet Ceres

NASA Astrophysics Data System (ADS)

Nayak, Michael

The Herschel Space Observatory recently detected the presence of water vapor in observations of Ceres, bringing it into the crosshairs of the search for the building blocks of life in the solar system. I present a mission concept designed in collaboration with the NASA Ames Research Center for a two-probe mission to the dwarf planet Ceres, utilizing a pair of small low-cost spacecraft. The primary spacecraft will carry both a mass and an infrared spectrometer to characterize the detected vapor. Shortly after its arrival a second and largely similar spacecraft will impact Ceres to create an impact ejecta "plume" timed to enable a rendezvous and sampling by the primary spacecraft. This enables additional subsurface chemistry, volatile content and material characterization, and new science complementary to the Dawn spacecraft, the first to arrive at Ceres. Science requirements, candidate instruments, rendezvous trajectories, spacecraft design and comparison with Dawn science are detailed.

Planet population synthesis driven by pebble accretion in cluster environments

NASA Astrophysics Data System (ADS)

Ndugu, N.; Bitsch, B.; Jurua, E.

2018-02-01

The evolution of protoplanetary discs embedded in stellar clusters depends on the age and the stellar density in which they are embedded. Stellar clusters of young age and high stellar surface density destroy protoplanetary discs by external photoevaporation and stellar encounters. Here, we consider the effect of background heating from newly formed stellar clusters on the structure of protoplanetary discs and how it affects the formation of planets in these discs. Our planet formation model is built on the core accretion scenario, where we take the reduction of the core growth time-scale due to pebble accretion into account. We synthesize planet populations that we compare to observations obtained by radial velocity measurements. The giant planets in our simulations migrate over large distances due to the fast type-II migration regime induced by a high disc viscosity (α = 5.4 × 10-3). Cold Jupiters (rp > 1 au) originate preferably from the outer disc, due to the large-scale planetary migration, while hot Jupiters (rp < 0.1 au) preferably form in the inner disc. We find that the formation of gas giants via pebble accretion is in agreement with the metallicity correlation, meaning that more gas giants are formed at larger metallicity. However, our synthetic population of isolated stars host a significant amount of giant planets even at low metallicity, in contradiction to observations where giant planets are preferably found around high metallicity stars, indicating that pebble accretion is very efficient in the standard pebble accretion framework. On the other hand, discs around stars embedded in cluster environments hardly form any giant planets at low metallicity in agreement with observations, where these changes originate from the increased temperature in the outer parts of the disc, which prolongs the core accretion time-scale of the planet. We therefore conclude that the outer disc structure and the planet's formation location determines the giant planet occurrence rate and the formation efficiency of cold and hot Jupiters.

The Giant Planet Satellite Exospheres

NASA Technical Reports Server (NTRS)

McGrath, Melissa A.

2014-01-01

Exospheres are relatively common in the outer solar system among the moons of the gas giant planets. They span the range from very tenuous, surface-bounded exospheres (e.g., Rhea, Dione) to quite robust exospheres with exobase above the surface (e.g., lo, Triton), and include many intermediate cases (e.g., Europa, Ganymede, Enceladus). The exospheres of these moons exhibit an interesting variety of sources, from surface sputtering, to frost sublimation, to active plumes, and also well illustrate another common characteristic of the outer planet satellite exospheres, namely, that the primary species often exists both as a gas in atmosphere, and a condensate (frost or ice) on the surface. As described by Yelle et al. (1995) for Triton, "The interchange of matter between gas and solid phases on these bodies has profound effects on the physical state of the surface and the structure of the atmosphere." A brief overview of the exospheres of the outer planet satellites will be presented, including an inter-comparison of these satellites exospheres with each other, and with the exospheres of the Moon and Mercury.

Compositional Remote Sensing of Icy Planets and Satellites Beyond Jupiter

NASA Technical Reports Server (NTRS)

Roush, T. 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.

TWO SMALL PLANETS TRANSITING HD 3167

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vanderburg, Andrew; Bieryla, Allyson; Latham, David W.

2016-09-20

We report the discovery of two super-Earth-sized planets transiting the bright (V = 8.94, K = 7.07) nearby late G-dwarf HD 3167, using data collected by the K2 mission. The inner planet, HD 3167 b, has a radius of 1.6 R {sub ⊕} and an ultra-short orbital period of only 0.96 days. The outer planet, HD 3167 c, has a radius of 2.9 R {sub ⊕} and orbits its host star every 29.85 days. At a distance of just 45.8 ± 2.2 pc, HD 3167 is one of the closest and brightest stars hosting multiple transiting planets, making HD 3167more » b and c well suited for follow-up observations. The star is chromospherically inactive with low rotational line-broadening, ideal for radial velocity observations to measure the planets’ masses. The outer planet is large enough that it likely has a thick gaseous envelope that could be studied via transmission spectroscopy. Planets transiting bright, nearby stars like HD 3167 are valuable objects to study leading up to the launch of the James Webb Space Telescope .« less

Geomorphological evidence for ground ice on dwarf planet Ceres

USGS Publications Warehouse

Schmidt, Britney E.; Hughson, Kynan H.G.; Chilton, Heather T.; Scully, Jennifer E. C.; Platz, Thomas; Nathues, Andreas; Sizemore, Hanna; Bland, Michael T.; Byrne, Shane; Marchi, Simone; O'Brien, David; Schorghofer, Norbert; Hiesinger, Harald; Jaumann, Ralf; Hendrick Pasckert, Jan; Lawrence, Justin D.; Buzckowski, Debra; Castillo-Rogez, Julie C.; Sykes, Mark V.; Schenk, Paul M.; DeSanctis, Maria-Cristina; Mitri, Giuseppe; Formisano, Michelangelo; Li, Jian-Yang; Reddy, Vishnu; Le Corre, Lucille; Russell, Christopher T.; Raymond, Carol A.

2017-01-01

Five decades of observations of Ceres suggest that the dwarf planet has a composition similar to carbonaceous meteorites and may have an ice-rich outer shell protected by a silicate layer. NASA’s Dawn spacecraft has detected ubiquitous clays, carbonates and other products of aqueous alteration across the surface of Ceres, but surprisingly it has directly observed water ice in only a few areas. Here we use Dawn Framing Camera observations to analyse lobate morphologies on Ceres’ surface and we infer the presence of ice in the upper few kilometres of Ceres. We identify three distinct lobate morphologies that we interpret as surface flows: thick tongue-shaped, furrowed flows on steep slopes; thin, spatulate flows on shallow slopes; and cuspate sheeted flows that appear fluidized. The shapes and aspect ratios of these flows are different from those of dry landslides—including those on ice-poor Vesta—but are morphologically similar to ice-rich flows on other bodies, indicating the involvement of ice. Based on the geomorphology and poleward increase in prevalence of these flows, we suggest that the shallow subsurface of Ceres is comprised of mixtures of silicates and ice, and that ice is most abundant near the poles.

Science goals and concepts of a Saturn probe for the future L2/L3 ESA call

NASA Astrophysics Data System (ADS)

Schmider, F.-X.; Mousis, O.; Fletcher, L. N.; Altwegg, K.; André, N.; Blanc, M.; Coustenis, A.; Gautier, D.; Geppert, W. D.; Guillot, T.; Irwin, P.; Lebreton, J.-P.; Marty, B.; Sánchez-Lavega, A.; Waite, J. H.; Wurz, P.

2013-11-01

Comparative studies of the elemental enrichments and isotopic abundances measured on Saturn can provide unique insights into the processes at work within our planetary system and are related to the time and location of giant planet formation. In situ measurements via entry probes remain the only reliable, unambiguous method for determining the atmospheric composition from the thermosphere to the deep cloud-forming regions of their complex weather layers. Furthermore, in situ experiments can reveal the meteorological properties of planetary atmospheres to provide ``ground truth'' for orbital remote sensing. Following the orbital reconnaissance of the Galileo and Cassini spacecraft, and the single-point in situ measurement of the Galileo probe to Jupiter, we believe that an in situ measurement of Saturn's atmospheric composition should be an essential element of ESA's future cornerstone missions, providing the much-needed comparative planetology to reveal the origins of our outer planets. This quest for understanding the origins of our solar system and the nature of planetary atmospheres is in the heart of ESA's Cosmic Vision, and has vast implications for the origins of planetary systems around other stars.

WASP-47 and the Origin of Hot Jupiters

NASA Astrophysics Data System (ADS)

Vanderburg, Andrew; Becker, Juliette; Latham, David W.; Adams, Fred; Bryan, Marta; Buchhave, Lars; Haywood, Raphaelle; Khain, Tali; Lopez, Eric; Malavolta, Luca; Mortier, Annelies; HARPS-N Consortium

2018-01-01

WASP-47 b is a transiting hot Jupiter in a system with two additional short-period transiting planets and a long-period outer Jovian companion. WASP-47 b is the only known hot Jupiter with such close-in companions and therefore may hold clues to the origins of hot Jupiter systems. We report on precise radial velocity observations of WASP-47 to measure planet masses and determine their orbits to high precision. Using these improved masses and orbital elements, we perform a dynamical analysis to constrain the inclination of the outer planet, which we find likely orbits near the same plane as the inner transiting system. A similar dynamical analysis for five other hot Jupiter systems with long-period companions around cool host stars (Teff < 6200 K) shows that these outer companions likely also orbit close to the plane of the hot Jupiters. These constraints disfavor hot Jupiter models involving strong dynamical interactions like Kozai-Lidov migration.

Connection Between the ICRF and the Dynamical Reference Frame for the Outer Planets

NASA Astrophysics Data System (ADS)

da Silva Neto, D. N.; Assafin, M.; Andrei, A. H.; Vieira Martins, R.

2005-01-01

This work brings an approach intending to improve the connection between the Dynamical Reference Frame and the Extragalactic Reference Frame. For that, close encounters of outer Solar System objects and quasars are used. With this goal, Uranus, Neptune and two quasars were observed at Laborat´orio Nacional de Astrof´ısica (LNA), Brazil. The optical reference frame is the HCRF, as given by the UCAC2 catalogue. The first results show an accuracy of 45 mas - 50 mas in the optical positions. The optical minus radio offsets give the local orientation between the catalogue and radio frame. From this, it is possible to place the optical planet coordinates on the extragalactic frame. A comparison between the new corrected optical coordinates and the respective DE ephemeris to these planets can give the instant orientations of the Dynamical Reference Frame with regard to the ICRS, for this zone of outer Solar System.

The Mars Climate Orbiter at Launch Complex 17A, CCAS

NASA Technical Reports Server (NTRS)

1998-01-01

At Launch Complex 17A, Cape Canaveral Air Station, the Mars Climate Orbiter is free of the protective canister that surrounded it during the move to the pad. Targeted for liftoff on Dec. 10, 1998, aboard a Boeing Delta II (7425) rocket, the orbiter will be the first spacecraft to be launched in the pair of Mars '98 missions. After its arrival at the red planet, the Mars Climate Orbiter will be used primarily to support its companion Mars Polar Lander spacecraft, scheduled for launch on Jan. 3, 1999. The orbiter will then monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year, the equivalent of about two Earth years. The spacecraft will observe the appearance and movement of atmospheric dust and water vapor, and characterize seasonal changes on the planet's surface.

The Mars Climate Orbiter at Launch Complex 17A, CCAS

NASA Technical Reports Server (NTRS)

1998-01-01

At Launch Complex 17A, Cape Canaveral Air Station, workers get ready to remove the last piece of the canister surrounding the Mars Climate Orbiter. Targeted for liftoff on Dec. 10, 1998, aboard a Boeing Delta II (7425) rocket, the orbiter will be the first spacecraft to be launched in the pair of Mars '98 missions. After its arrival at the red planet, the Mars Climate Orbiter will be used primarily to support its companion Mars Polar Lander spacecraft, scheduled for launch on Jan. 3, 1999. The orbiter will then monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year, the equivalent of about two Earth years. The spacecraft will observe the appearance and movement of atmospheric dust and water vapor, and characterize seasonal changes on the planet's surface.

KSC-98pc1815

NASA Image and Video Library

1998-12-01

KENNEDY SPACE CENTER, FLA. -- At Launch Complex 17A, Cape Canaveral Air Station, workers get ready to remove the last piece of the canister surrounding the Mars Climate Orbiter. Targeted for liftoff on Dec. 10, 1998, aboard a Boeing Delta II (7425) rocket, the orbiter will be the first spacecraft to be launched in the pair of Mars '98 missions. After its arrival at the red planet, the Mars Climate Orbiter will be used primarily to support its companion Mars Polar Lander spacecraft, scheduled for launch on Jan. 3, 1999. The orbiter will then monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year, the equivalent of about two Earth years. The spacecraft will observe the appearance and movement of atmospheric dust and water vapor, and characterize seasonal changes on the planet's surface

KSC-98pc1816

NASA Image and Video Library

1998-12-01

KENNEDY SPACE CENTER, FLA. -- At Launch Complex 17A, Cape Canaveral Air Station, the Mars Climate Orbiter is free of the protective canister that surrounded it during the move to the pad. Targeted for liftoff on Dec. 10, 1998, aboard a Boeing Delta II (7425) rocket, the orbiter will be the first spacecraft to be launched in the pair of Mars '98 missions. After its arrival at the red planet, the Mars Climate Orbiter will be used primarily to support its companion Mars Polar Lander spacecraft, scheduled for launch on Jan. 3, 1999. The orbiter will then monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year, the equivalent of about two Earth years. The spacecraft will observe the appearance and movement of atmospheric dust and water vapor, and characterize seasonal changes on the planet's surface

The California-Kepler Survey. V. Peas in a Pod: Planets in a Kepler Multi-planet System Are Similar in Size and Regularly Spaced

NASA Astrophysics Data System (ADS)

Weiss, Lauren M.; Marcy, Geoffrey W.; Petigura, Erik A.; Fulton, Benjamin J.; Howard, Andrew W.; Winn, Joshua N.; Isaacson, Howard T.; Morton, Timothy D.; Hirsch, Lea A.; Sinukoff, Evan J.; Cumming, Andrew; Hebb, Leslie; Cargile, Phillip A.

2018-01-01

We have established precise planet radii, semimajor axes, incident stellar fluxes, and stellar masses for 909 planets in 355 multi-planet systems discovered by Kepler. In this sample, we find that planets within a single multi-planet system have correlated sizes: each planet is more likely to be the size of its neighbor than a size drawn at random from the distribution of observed planet sizes. In systems with three or more planets, the planets tend to have a regular spacing: the orbital period ratios of adjacent pairs of planets are correlated. Furthermore, the orbital period ratios are smaller in systems with smaller planets, suggesting that the patterns in planet sizes and spacing are linked through formation and/or subsequent orbital dynamics. Yet, we find that essentially no planets have orbital period ratios smaller than 1.2, regardless of planet size. Using empirical mass–radius relationships, we estimate the mutual Hill separations of planet pairs. We find that 93% of the planet pairs are at least 10 mutual Hill radii apart, and that a spacing of ∼20 mutual Hill radii is most common. We also find that when comparing planet sizes, the outer planet is larger in 65% ± 0.4% of cases, and the typical ratio of the outer to inner planet size is positively correlated with the temperature difference between the planets. This could be the result of photo-evaporation. Based on observations obtained at the W. M. Keck Observatory, which is operated jointly by the University of California and the California Institute of Technology. Keck time has been granted by the University of California, and California Institute of Technology, and the University of Hawaii.

Studies on possible propagation of microbial contamination in planetary clouds

NASA Technical Reports Server (NTRS)

Dimmick, R. L.; Chatigny, M. A.; Wolochow, H.

1973-01-01

One of the key parameters in estimation of the probability of contamintion of the outer planets (Jupiter, Saturn, Uranus, etc.) is the probability of growth (Pg) of terrestrial microorganisms on or near these planets. For example, Jupiter appears to have an atmosphere in which some microbial species could metabolize and propagate. This study includes investigation of the likelihood of metabolism and propagation of microbes suspended in dynamic atmospheres. It is directed toward providing experimental information needed to aid in rational estimation of Pg for these outer planets. Current work is directed at demonstration of aerial metabolism under near optimal conditions and tests of propagation in simulated Jovian atmospheres.

Studies on possible propagation of microbial contamination in planetary clouds

NASA Technical Reports Server (NTRS)

Dimmick, R. L.; Chatigny, M. A.

1973-01-01

Current U.S. planetary quarantine standards based on international agreements require consideration of the probability of contamination (Pc) of the outer planets, Venus, Jupiter, Saturn, etc. One of the key parameters in estimation of the Pc of these planets is the probability of growth (Pg) of terrestrial microorganisms on or near these planets. For example, Jupiter and Saturn appear to have an atmosphere in which some microbial species could metabolize and propagate. This study includes investigation of the likelihood of metabolism and propagation of microbes suspended in dynamic atmospheres. It is directed toward providing experimental information needed to aid in rational estimation of Pg for these outer plants.

Automated design of gravity-assist trajectories to Mars and the outer planets

NASA Technical Reports Server (NTRS)

Longuski, James M.; Williams, Steve N.

1991-01-01

In this paper, a new approach to planetary mission design is described which automates the search for gravity-assist trajectories. This method finds all conic solutions given a range of launch dates, a range of launch energies and a set of target planets. The new design tool is applied to the problems of finding multiple encounter trajectories to the outer planets and Venus gravity-assist trajectories to Mars. The last four-planet grand tour opportunity (until the year 2153) is identified. It requires an earth launch in 1996 and encounters Jupiter, Uranus, Neptune, and Pluto. Venus gravity-assist trajectories to Mars for the 30 year period 1995-2024 are examined. It is shown that in many cases these trajectories require less launch energy to reach Mars than direct ballistic trajectories.

Preliminary science results of Voyager 1 Saturn encounter

NASA Technical Reports Server (NTRS)

Bane, D.

1981-01-01

Preliminary science results of the Voyager 1 encounter of the planet Saturn are reported. On August 22, 1980, the spacecraft was 109 million km (68 million mi) from Saturn. Closest approach to Saturn took place on November 12, at 3:46 p.m. (PDT), when the spacecraft passed 126,000 km (78,000 mi) from the cloud tops. Measurements of the atmosphere, wind speed, radiation, six surrounding rings, and the planet's old and newly found satellites were recorded. The encounter ended December 15, 1980. The spacecraft took more than 17,500 photographs of Saturn and its satellites.

Obtaining coincident image observations for Mission to Planet Earth science data return

NASA Technical Reports Server (NTRS)

Newman, Lauri Kraft; Folta, David C.; Farrell, James P.

1994-01-01

One objective of the Mission to Planet Earth (MTPE) program involves comparing data from various instruments on multiple spacecraft to obtain a total picture of the Earth's systems. To correlate image data from instruments on different spacecraft, these spacecraft must be able to image the same location on the Earth at approximately the same time. Depending on the orbits of the spacecraft involved, complicated operational details must be considered to obtain such observations. If the spacecraft are in similar orbits, close formation flying or synchronization techniques may be used to assure coincident observations. If the orbits are dissimilar, the launch time of the second satellite may need to be restricted in order to align its orbit with that of the first satellite launched. This paper examines strategies for obtaining coincident observations for spacecraft in both similar and dissimilar orbits. Although these calculations may be performed easily for coplanar spacecraft, the non-coplanar case involves additional considerations which are incorporated into the algorithms presented herein.

Searching for Chips of Kuiper Belt Objects in Meteorites

NASA Technical Reports Server (NTRS)

Zolensky, M. E.; Ohsumi, K.; Briani, G.; Gounelle, M.; Mikouchi, T.; Satake, W.; Kurihara, T.; Weisberg, M. K.; Le, L.

2009-01-01

The Nice model [1&2] describes a scenario whereby the Jovian planets experienced a violent reshuffling event approx.3:9 Ga the giant planets moved, existing small body reservoirs were depleted or eliminated, and new reservoirs were created in particular locations. The Nice model quantitatively explains the orbits of the Jovian planets and Neptune [1], the orbits of bodies in several different small body reservoirs in the outer solar system (e.g., Trojans of Jupiter [2], the Kuiper belt and scattered disk [3], the irregular satellites of the giant planets [4], and the late heavy bombardment on the terrestrial planets approx.3:9 Ga [5]. This model is unique in plausibly explaining all of these phenomena. One issue with the Nice model is that it predicts that transported Kuiper Belt Objects (KBOs) (things looking like D class asteroids) should predominate in the outer asteroid belt, but we know only about 10% of the objects in the outer main asteroid belt appear to be D-class objects [6]. However based upon collisional modeling, Bottke et al. [6] argue that more than 90% of the objects captured in the outer main belt could have been eliminated by impacts if they had been weakly-indurated objects. These disrupted objects should have left behind pieces in the ancient regoliths of other, presumably stronger asteroids. Thus, a derived prediction of the Nice model is that ancient regolith samples (regolith-bearing meteorites) should contain fragments of collisionally-destroyed Kuiper belt objects. In fact KBO pieces might be expected to be present in most ancient regolith- bearing meteorites [7&8].

Time Synchronization and Distribution Mechanisms for Space Networks

NASA Technical Reports Server (NTRS)

Woo, Simon S.; Gao, Jay L.; Clare, Loren P.; Mills, David L.

2011-01-01

This work discusses research on the problems of synchronizing and distributing time information between spacecraft based on the Network Time Protocol (NTP), where NTP is a standard time synchronization protocol widely used in the terrestrial network. The Proximity-1 Space Link Interleaved Time Synchronization (PITS) Protocol was designed and developed for synchronizing spacecraft that are in proximity where proximity is less than 100,000 km distant. A particular application is synchronization between a Mars orbiter and rover. Lunar scenarios as well as outer-planet deep space mother-ship-probe missions may also apply. Spacecraft with more accurate time information functions as a time-server, and the other spacecraft functions as a time-client. PITS can be easily integrated and adaptable to the CCSDS Proximity-1 Space Link Protocol with minor modifications. In particular, PITS can take advantage of the timestamping strategy that underlying link layer functionality provides for accurate time offset calculation. The PITS algorithm achieves time synchronization with eight consecutive space network time packet exchanges between two spacecraft. PITS can detect and avoid possible errors from receiving duplicate and out-of-order packets by comparing with the current state variables and timestamps. Further, PITS is able to detect error events and autonomously recover from unexpected events that can possibly occur during the time synchronization and distribution process. This capability achieves an additional level of protocol protection on top of CRC or Error Correction Codes. PITS is a lightweight and efficient protocol, eliminating the needs for explicit frame sequence number and long buffer storage. The PITS protocol is capable of providing time synchronization and distribution services for a more general domain where multiple entities need to achieve time synchronization using a single point-to-point link.

Unraveling the Reaction Chemistry of Icy Ocean World Surfaces

NASA Astrophysics Data System (ADS)

Hudson, R.; Loeffler, M. J.; Gerakines, P.

2017-12-01

The diverse endogenic chemistry of ocean worlds can be divided among interior, surface, and above-surface process, with contributions from exogenic agents such as solar, cosmic, and magnetospheric radiation. Bombardment from micrometeorites to comets also can influence chemistry by both delivering new materials and altering pre-existing ones, and providing energy to drive reactions. Geological processes further complicate the chemistry by transporting materials from one environment to another. In this presentation the focus will be on some of the thermally driven and radiation-induced changes expected from icy materials, primarily covalent and ionic compounds. Low-temperature conversions of a few relatively simple molecules into ions possessing distinct infrared (IR) features will be covered, with an emphasis on such features as might be identified through either orbiting spacecraft or landers. The low-temperature degradation of a few bioorganic molecules, such as DNA nucleobases and some common amino acids, will be used as examples of the more complex, and potentially misleading, chemistry expected for icy moons of the outer solar system. This work was supported by NASA's Emerging Worlds and Outer Planets Research programs, as well as the NASA Astrobiology Institute's Goddard Center for Astrobiology.

Proceedings of the 39th Lunar and Planetary Science Conference

NASA Technical Reports Server (NTRS)

2008-01-01

Sessions with oral presentations include: A SPECIAL SESSION: MESSENGER at Mercury, Mars: Pingos, Polygons, and Other Puzzles, Solar Wind and Genesis: Measurements and Interpretation, Asteroids, Comets, and Small Bodies, Mars: Ice On the Ground and In the Ground, SPECIAL SESSION: Results from Kaguya (SELENE) Mission to the Moon, Outer Planet Satellites: Not Titan, Not Enceladus, SPECIAL SESSION: Lunar Science: Past, Present, and Future, Mars: North Pole, South Pole - Structure and Evolution, Refractory Inclusions, Impact Events: Modeling, Experiments, and Observations, Mars Sedimentary Processes from Victoria Crater to the Columbia Hills, Formation and Alteration of Carbonaceous Chondrites, New Achondrite GRA 06128/GRA 06129 - Origins Unknown, The Science Behind Lunar Missions, Mars Volcanics and Tectonics, From Dust to Planets (Planetary Formation and Planetesimals):When, Where, and Kaboom! Astrobiology: Biosignatures, Impacts, Habitability, Excavating a Comet, Mars Interior Dynamics to Exterior Impacts, Achondrites, Lunar Remote Sensing, Mars Aeolian Processes and Gully Formation Mechanisms, Solar Nebula Shake and Bake: Mixing and Isotopes, Lunar Geophysics, Meteorites from Mars: Shergottite and Nakhlite Invasion, Mars Fluvial Geomorphology, Chondrules and Chondrule Formation, Lunar Samples: Chronology, Geochemistry, and Petrology, Enceladus, Venus: Resurfacing and Topography (with Pancakes!), Overview of the Lunar Reconnaissance Orbiter Mission, Mars Sulfates, Phyllosilicates, and Their Aqueous Sources, Ordinary and Enstatite Chondrites, Impact Calibration and Effects, Comparative Planetology, Analogs: Environments and Materials, Mars: The Orbital View of Sediments and Aqueous Mineralogy, Planetary Differentiation, Titan, Presolar Grains: Still More Isotopes Out of This World, Poster sessions include: Education and Public Outreach Programs, Early Solar System and Planet Formation, Solar Wind and Genesis, Asteroids, Comets, and Small Bodies, Carbonaceous Chondrites, Chondrules and Chondrule Formation, Chondrites, Refractory Inclusions, Organics in Chondrites, Meteorites: Techniques, Experiments, and Physical Properties, MESSENGER and Mercury, Lunar Science Present: Kaguya (SELENE) Results, Lunar Remote Sensing: Basins and Mapping of Geology and Geochemistry, Lunar Science: Dust and Ice, Lunar Science: Missions and Planning, Mars: Layered, Icy, and Polygonal, Mars Stratigraphy and Sedimentology, Mars (Peri)Glacial, Mars Polar (and Vast), Mars, You are Here: Landing Sites and Imagery, Mars Volcanics and Magmas, Mars Atmosphere, Impact Events: Modeling, Experiments, and Observation, Ice is Nice: Mostly Outer Planet Satellites, Galilean Satellites, The Big Giant Planets, Astrobiology, In Situ Instrumentation, Rocket Scientist's Toolbox: Mission Science and Operations, Spacecraft Missions, Presolar Grains, Micrometeorites, Condensation-Evaporation: Stardust Ties, Comet Dust, Comparative Planetology, Planetary Differentiation, Lunar Meteorites, Nonchondritic Meteorites, Martian Meteorites, Apollo Samples and Lunar Interior, Lunar Geophysics, Lunar Science: Geophysics, Surface Science, and Extralunar Components, Mars, Remotely, Mars Orbital Data - Methods and Interpretation, Mars Tectonics and Dynamics, Mars Craters: Tiny to Humongous, Mars Sedimentary Mineralogy, Martian Gullies and Slope Streaks, Mars Fluvial Geomorphology, Mars Aeolian Processes, Mars Data and Mission,s Venus Mapping, Modeling, and Data Analysis, Titan, Icy Dwarf Satellites, Rocket Scientist's Toolbox: In Situ Analysis, Remote Sensing Approaches, Advances, and Applications, Analogs: Sulfates - Earth and Lab to Mars, Analogs: Remote Sensing and Spectroscopy, Analogs: Methods and Instruments, Analogs: Weird Places!. Print Only Early Solar System, Solar Wind, IDPs, Presolar/Solar Grains, Stardust, Comets, Asteroids, and Phobos, Venus, Mercury, Moon, Meteorites, Mars, Astrobiology, Impacts, Outer Planets, Satellites, and Rings, Support for Mission Operations, Analog Education and Public Outreach.

Chaos in Kepler's Multiple Planet Systems and K2s Observations of the Atmospheres of Uranus Neptune

NASA Technical Reports Server (NTRS)

Lissauer, Jack J.

2016-01-01

More than one-third of the 4700 planet candidates found by NASA's Kepler spacecraft during its prime mission are associated with target stars that have more than one planet candidate, and such "multis" account for the vast majority of candidates that have been verified as true planets. The large number of multis tells us that flat multiplanet systems like our Solar System are common. Virtually all of the candidate planetary systems are stable, as tested by numerical integrations that assume a physically motivated mass-radius relationship, but some of the systems lie in chaotic regions close to instability. The characteristics of some of the most interesting confirmed Kepler multi-planet systems will be discussed. The Kepler spacecraft's 'second life' in theK2 mission has allowed it to obtain long time-series observations of Solar System targets, including the giant planets Uranus & Neptune. These observations show variability caused by the chaotic weather patterns on Uranus & Neptune.

A radiometric Bode's Law: Predictions for Uranus

NASA Technical Reports Server (NTRS)

Desch, M. D.; Kaiser, M. L.

1984-01-01

The magnetospheres of three planets, Earth, Jupiter, and Saturn, are known to be sources of intense, nonthermal radio bursts. The emissions from these sources undergo pronounced long term intensity fluctuations that are caused by the solar wind interaction with the magnetosphere of each planet. Determinations by spacecraft of the low frequency radio spectra and radiation beam geometry now permit a reliable assessment of the overall efficiency of the solar wind in stimulating these emissions. Earlier estimates of how magnetospheric radio output scales with the solar wind energy input must be revised greatly, with the result that, while the efficiency is much lower than previously thought, it is remarkably uniform from planet to planet. The formulation of a radiometric Bode's Law from which a planet's magnetic moment is estimated from its radio emission output is presented. Applying the radiometric scaling law to Uranus, the low-frequency radio power is likely to be measured by the Voyager 2 spacecraft as it approaches this planet.

Reaching for the red planet

PubMed

David, L

1996-05-01

The distant shores of Mars were reached by numerous U.S. and Russian spacecraft throughout the 1960s to mid 1970s. Nearly 20 years have passed since those successful missions which orbited and landed on the Martian surface. Two Soviet probes headed for the planet in July, 1988, but later failed. In August 1993, the U.S. Mars Observer suddenly went silent just three days before it was to enter orbit around the planet and was never heard from again. In late 1996, there will be renewed activity on the launch pads with three probes departing for the red planet: 1) The U.S. Mars Global Surveyor will be launched in November on a Delta II rocket and will orbit the planet for global mapping purposes; 2) Russia's Mars '96 mission, scheduled to fly in November on a Proton launcher, consists of an orbiter, two small stations which will land on the Martian surface, and two penetrators that will plow into the terrain; and finally, 3) a U.S. Discovery-class spacecraft, the Mars Pathfinder, has a December launch date atop a Delta II booster. The mission features a lander and a microrover that will travel short distances over Martian territory. These missions usher in a new phase of Mars exploration, setting the stage for an unprecedented volley of spacecraft that will orbit around, land on, drive across, and perhaps fly at low altitudes over the planet.

Thermal Protection System with Staggered Joints

NASA Technical Reports Server (NTRS)

Simon, Xavier D. (Inventor); Robinson, Michael J. (Inventor); Andrews, Thomas L. (Inventor)

2014-01-01

The thermal protection system disclosed herein is suitable for use with a spacecraft such as a reentry module or vehicle, where the spacecraft has a convex surface to be protected. An embodiment of the thermal protection system includes a plurality of heat resistant panels, each having an outer surface configured for exposure to atmosphere, an inner surface opposite the outer surface and configured for attachment to the convex surface of the spacecraft, and a joint edge defined between the outer surface and the inner surface. The joint edges of adjacent ones of the heat resistant panels are configured to mate with each other to form staggered joints that run between the peak of the convex surface and the base section of the convex surface.

Trajectory and System Analysis For Outer-Planet Solar-Electric Propulsion Missions

NASA Technical Reports Server (NTRS)

Cupples, Michael; Woo, Byoungsam; Coverstone, Victoria L.; Hartmann, John W.

2004-01-01

Outer-planet mission and systems analyses are performed using three next generation solar-electric ion thruster models. The impact of variations in thruster model, flight time, launch vehicle, propulsion and power systems characteristics is investigated. All presented trajectories have a single Venus gravity assist and maximize the delivered mass to Saturn or Neptune. The effect of revolution ratio - the ratio of Venusian orbital period to the flight time between launch and flyby dates - is also discussed.

Habitable zone limits for dry planets.

PubMed

Abe, Yutaka; Abe-Ouchi, Ayako; Sleep, Norman H; Zahnle, Kevin J

2011-06-01

Most discussion of habitable planets has focused on Earth-like planets with globally abundant liquid water. For an "aqua planet" like Earth, the surface freezes if far from its sun, and the water vapor greenhouse effect runs away if too close. Here we show that "land planets" (desert worlds with limited surface water) have wider habitable zones than aqua planets. For planets at the inner edge of the habitable zone, a land planet has two advantages over an aqua planet: (i) the tropics can emit longwave radiation at rates above the traditional runaway limit because the air is unsaturated and (ii) the dry air creates a dry stratosphere that limits hydrogen escape. At the outer limits of the habitable zone, the land planet better resists global freezing because there is less water for clouds, snow, and ice. Here we describe a series of numerical experiments using a simple three-dimensional global climate model for Earth-sized planets. Other things (CO(2), rotation rate, surface pressure) unchanged, we found that liquid water remains stable at the poles of a low-obliquity land planet until net insolation exceeds 415 W/m(2) (170% that of modern Earth), compared to 330 W/m(2) (135%) for the aqua planet. At the outer limits, we found that a low-obliquity land planet freezes at 77%, while the aqua planet freezes at 90%. High-obliquity land and aqua planets freeze at 58% and 72%, respectively, with the poles offering the last refuge. We show that it is possible that, as the Sun brightens, an aqua planet like Earth can lose most of its hydrogen and become a land planet without first passing through a sterilizing runaway greenhouse. It is possible that Venus was a habitable land planet as recently as 1 billion years ago.

Massive Gas Cloud Around Jupiter

NASA Technical Reports Server (NTRS)

2003-01-01

An innovative instrument on NASA's Cassini spacecraft makes the space environment around Jupiter visible, revealing a donut-shaped gas cloud encircling the planet.

The image was taken with the energetic neutral atom imaging technique by the Magnetospheric Imaging Instrument on Cassini as the spacecraft flew past Jupiter in early 2001 at a distance of about 10 million kilometers (6 million miles). This technique provides information about a source by detecting neutral atoms emitted by the source, comparable to how a camera reveals information about an object by detecting photons coming from the object.

The central object in this image represents energetic neutral atom emissions from Jupiter itself. The outer two objects represent emissions from a donut-shaped cloud, or torus, that shares an orbit with Jupiter's moon Europa. The cloud's emissions appear dot-like because of the viewing angle. The torus is viewed edge-on, and the image is brightest at the line-of-sight angles that pass through the greatest volume of it.

Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages Cassini for NASA's Office of Space Science, Washington, D.C.

Nuclear Electric Propulsion for Deep Space Exploration

NASA Astrophysics Data System (ADS)

Schmidt, G.

Nuclear electric propulsion (NEP) holds considerable promise for deep space exploration in the future. Research and development of this technology is a key element of NASA's Nuclear Systems Initiative (NSI), which is a top priority in the President's FY03 NASA budget. The goal is to develop the subsystem technologies that will enable application of NEP for missions to the outer planets and beyond by the beginning of next decade. The high-performance offered by nuclear-powered electric thrusters will benefit future missions by (1) reducing or eliminating the launch window constraints associated with complex planetary swingbys, (2) providing the capability to perform large spacecraft velocity changes in deep space, (3) increasing the fraction of vehicle mass allocated to payload and other spacecraft systems, and, (3) in some cases, reducing trip times over other propulsion alternatives. Furthermore, the nuclear energy source will provide a power-rich environment that can support more sophisticated science experiments and higher- speed broadband data transmission than current deep space missions. This paper addresses NASA's plans for NEP, and discusses the subsystem technologies (i.e., nuclear reactors, power conversion and electric thrusters) and system concepts being considered for the first generation of NEP vehicles.

Time-lapse Sequence of Jupiter's South Pole

NASA Image and Video Library

2018-02-22

This series of images captures cloud patterns near Jupiter's south pole, looking up towards the planet's equator. NASA's Juno spacecraft took the color-enhanced time-lapse sequence of images during its eleventh close flyby of the gas giant planet on Feb. 7 between 7:21 a.m. and 8:01 a.m. PST (10:21 a.m. and 11:01 a.m. EST). At the time, the spacecraft was between 85,292 to 124,856 miles (137,264 to 200,937 kilometers) from the tops of the clouds of the planet with the images centered on latitudes from 84.1 to 75.5 degrees south. At first glance, the series might appear to be the same image repeated. But closer inspection reveals slight changes, which are most easily noticed by comparing the far left image with the far right image. Directly, the images show Jupiter. But, through slight variations in the images, they indirectly capture the motion of the Juno spacecraft itself, once again swinging around a giant planet hundreds of millions of miles from Earth. https://photojournal.jpl.nasa.gov/catalog/PIA21979

Juno on Jupiter Doorstep

NASA Image and Video Library

2016-06-24

NASA's Juno spacecraft obtained this color view on June 21, 2016, at a distance of 6.8 million miles (10.9 million kilometers) from Jupiter. As Juno makes its initial approach, the giant planet's four largest moons -- Io, Europa, Ganymede and Callisto -- are visible, and the alternating light and dark bands of the planet's clouds are just beginning to come into view. Juno is approaching over Jupiter's north pole, affording the spacecraft a unique perspective on the Jupiter system. Previous missions that imaged Jupiter on approach saw the system from much lower latitudes, closer to the planet's equator. The scene was captured by the mission's imaging camera, called JunoCam, which is designed to acquire high resolution views of features in Jupiter's atmosphere from very close to the planet. http://photojournal.jpl.nasa.gov/catalog/PIA20701

Geologic Exploration of the Planets: The First 50 Years

NASA Astrophysics Data System (ADS)

Carr, Michael H.

2013-01-01

Fifty years ago, on 14 December 1962, the Mariner 2 spacecraft flew by Venus and inaugurated the modern era of planetary exploration. Since that first Venus flyby, roughly 80 spacecraft have successfully probed, orbited, flown by, landed on, or roved on other planets, satellites, asteroids, and comets. As Carl Sagan used to say, only one generation of humankind can be the first explorers of the solar system, and we are that generation.

KSC-98pc1046

NASA Image and Video Library

1998-09-11

The Mars Climate Orbiter spacecraft arrives at KSC's Shuttle Landing Facility aboard an Air Force C-17 cargo plane early this morning following its flight from the Lockheed Martin Astronautics plant in Denver, Colo. When the spacecraft arrives at the red planet, it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (1.8 Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Delta II 7425 rocket

The Mars Climate Orbiter is lifted up the Pad 17A gantry

NASA Technical Reports Server (NTRS)

1998-01-01

Wrapped in a protective covering, the Mars Climate Orbiter with its upper stage booster is lifted up at Launch Complex 17, Pad A, Cape Canaveral Air Station, in preparation for mating to the second stage of a Boeing Delta II (7425) rocket. Targeted for liftoff on Dec. 10, 1998, the orbiter will be the first spacecraft to be launched in the pair of Mars '98 missions. After its arrival at the red planet, the Mars Climate Orbiter will be used primarily to support its companion Mars Polar Lander spacecraft, scheduled for launch on Jan. 3, 1999. The orbiter will then monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year, the equivalent of about two Earth years. The spacecraft will observe the appearance and movement of atmospheric dust and water vapor, and characterize seasonal changes on the planet's surface.

The Mars Climate Orbiter is lifted up the Pad 17A gantry

NASA Technical Reports Server (NTRS)

1998-01-01

The Mars Climate Orbiter with its upper stage booster, wrapped in a protective covering, is mated to the second stage of a Boeing Delta II (7425) rocket at Launch Complex 17, Pad A, Cape Canaveral Air Station. Targeted for liftoff on Dec. 10, 1998, the orbiter will be the first spacecraft to be launched in the pair of Mars '98 missions. After its arrival at the red planet, the Mars Climate Orbiter will be used primarily to support its companion Mars Polar Lander spacecraft, scheduled for launch on Jan. 3, 1999. The orbiter will then monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year, the equivalent of about two Earth years. The spacecraft will observe the appearance and movement of atmospheric dust and water vapor, and characterize seasonal changes on the planet's surface.

The Mars Climate Orbiter is lifted up the Pad 17A gantry

NASA Technical Reports Server (NTRS)

1998-01-01

Wrapped in a protective covering, the Mars Climate Orbiter with its upper stage booster is lowered in preparation for mating to the second stage of a Boeing Delta II (7425) rocket at Launch Complex 17, Pad A, Cape Canaveral Air Station. Targeted for liftoff on Dec. 10, 1998, the orbiter will be the first spacecraft to be launched in the pair of Mars '98 missions. After its arrival at the red planet, the Mars Climate Orbiter will be used primarily to support its companion Mars Polar Lander spacecraft, scheduled for launch on Jan. 3, 1999. The orbiter will then monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year, the equivalent of about two Earth years. The spacecraft will observe the appearance and movement of atmospheric dust and water vapor, and characterize seasonal changes on the planet's surface.

Juno Arrival at Jupiter Artist Concept

NASA Image and Video Library

2015-07-07

This artist's rendering shows NASA's Juno spacecraft making one of its close passes over Jupiter. Launched in 2011, the Juno spacecraft will arrive at Jupiter in 2016 to study the giant planet from an elliptical, polar orbit. Juno will repeatedly dive between the planet and its intense belts of charged particle radiation, traveling from pole to pole in about an hour, and coming within 5,000 kilometers (about 3,000 miles) of the cloud tops at closest approach. Juno's primary goal is to improve our understanding of Jupiter's formation and evolution. The spacecraft will spend a little over a year investigating the planet's origins, interior structure, deep atmosphere and magnetosphere. Juno's study of Jupiter will help us to understand the history of our own solar system and provide new insight into how planetary systems form and develop in our galaxy and beyond. http://photojournal.jpl.nasa.gov/catalog/PIA19639

Planetary Interiors

NASA Technical Reports Server (NTRS)

Banerdt, W. Bruce; Abercrombie, Rachel; Keddie, Susan; Mizutani, Hitoshi; Nagihara, Seiichi; Nakamura, Yosio; Pike, W. Thomas

1996-01-01

This report identifies two main themes to guide planetary science in the next two decades: understanding planetary origins, and understanding the constitution and fundamental processes of the planets themselves. Within the latter theme, four specific goals related to interior measurements addressing the theme. These are: (1) Understanding the internal structure and dynamics of at least one solid body, other than the Earth or Moon, that is actively convecting, (2) Determine the characteristics of the magnetic fields of Mercury and the outer planets to provide insight into the generation of planetary magnetic fields, (3) Specify the nature and sources of stress that are responsible for the global tectonics of Mars, Venus, and several icy satellites of the outer planets, and (4) Advance significantly our understanding of crust-mantle structure for all the solid planets. These goals can be addressed almost exclusively by measurements made on the surfaces of planetary bodies.

Jupiter: Cosmic Jekyll and Hyde.

PubMed

Grazier, Kevin R

2016-01-01

It has been widely reported that Jupiter has a profound role in shielding the terrestrial planets from comet impacts in the Solar System, and that a jovian planet is a requirement for the evolution of life on Earth. To evaluate whether jovians, in fact, shield habitable planets from impacts (a phenomenon often referred to as the "Jupiter as shield" concept), this study simulated the evolution of 10,000 particles in each of the jovian inter-planet gaps for the cases of full-mass and embryo planets for up to 100 My. The results of these simulations predict a number of phenomena that not only discount the "Jupiter as shield" concept, they also predict that in a Solar System like ours, large gas giants like Saturn and Jupiter had a different, and potentially even more important, role in the evolution of life on our planet by delivering the volatile-laden material required for the formation of life. The simulations illustrate that, although all particles occupied "non-life threatening" orbits at their onset of the simulations, a significant fraction of the 30,000 particles evolved into Earth-crossing orbits. A comparison of multiple runs with different planetary configurations revealed that Jupiter was responsible for the vast majority of the encounters that "kicked" outer planet material into the terrestrial planet region, and that Saturn assisted in the process far more than has previously been acknowledged. Jupiter also tends to "fix" the aphelion of planetesimals at its orbit irrespective of their initial starting zones, which has the effect of slowing their passages through the inner Solar System, and thus potentially improving the odds of accretion of cometary material by terrestrial planets. As expected, the simulations indicate that the full-mass planets perturb many objects into the deep outer Solar System, or eject them entirely; however, planetary embryos also did this with surprising efficiency. Finally, the simulations predict that Jupiter's capacity to shield or intercept Earth-bound comets originating in the outer Solar System is poor, and that the importance of jovian planets on the formation of life is not that they act as shields, but rather that they deliver life-enabling volatiles to the terrestrial planets.

NASA’s Hubble Telescope Finds Potential Kuiper Belt Targets for New Horizons Pluto Mission

NASA Image and Video Library

2017-12-08

This is an artist’s impression of a Kuiper Belt object (KBO), located on the outer rim of our solar system at a staggering distance of 4 billion miles from the Sun. A HST survey uncovered three KBOs that are potentially reachable by NASA’s New Horizons spacecraft after it passes by Pluto in mid-2015. Credit: NASA, ESA, and G. Bacon (STScI) --- Peering out to the dim, outer reaches of our solar system, NASA’s Hubble Space Telescope has uncovered three Kuiper Belt objects (KBOs) the agency’s New Horizons spacecraft could potentially visit after it flies by Pluto in July 2015. The KBOs were detected through a dedicated Hubble observing program by a New Horizons search team that was awarded telescope time for this purpose. “This has been a very challenging search and it’s great that in the end Hubble could accomplish a detection – one NASA mission helping another,” said Alan Stern of the Southwest Research Institute (SwRI) in Boulder, Colorado, principal investigator of the New Horizons mission. The Kuiper Belt is a vast rim of primordial debris encircling our solar system. KBOs belong to a unique class of solar system objects that has never been visited by spacecraft and which contain clues to the origin of our solar system. The KBOs Hubble found are each about 10 times larger than typical comets, but only about 1-2 percent of the size of Pluto. Unlike asteroids, KBOs have not been heated by the sun and are thought to represent a pristine, well preserved deep-freeze sample of what the outer solar system was like following its birth 4.6 billion years ago. The KBOs found in the Hubble data are thought to be the building blocks of dwarf planets such as Pluto. Read more: 1.usa.gov/1vzUcyK NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Structure of the Iconic Vega Debris Disk

NASA Astrophysics Data System (ADS)

Su, Kate

2015-10-01

Debris structures provide the best means to explore planets down to ice-giant masses in the outer (>5 AU) parts of extrasolar planetary systems. It is thought that the iconic Vega debris disk composes of two separate belts shepherded by unseen planets, similar to the Solar System. We will probe this possibility with SOFIA at 35 microns by: 1.) documenting the structure of the debris with sufficient resolution to distinguish a separate warm belt from the alternative model of dust flowing inward from the outer debris ring; and 2.) testing for traces of dust in its 15-60 AU zone and thus probing the possibility that ice giant planets may be shepherding the debris belts.

The Deep Space Network as an instrument for radio science research

NASA Technical Reports Server (NTRS)

Asmar, S. W.; Renzetti, N. A.

1993-01-01

Radio science experiments use radio links between spacecraft and sensor instrumentation that is implemented in the Deep Space Network. The deep space communication complexes along with the telecommunications subsystem on board the spacecraft constitute the major elements of the radio science instrumentation. Investigators examine small changes in the phase and/or amplitude of the radio signal propagating from a spacecraft to study the atmospheric and ionospheric structure of planets and satellites, planetary gravitational fields, shapes, masses, planetary rings, ephemerides of planets, solar corona, magnetic fields, cometary comae, and such aspects of the theory of general relativity as gravitational waves and gravitational redshift.

Formation Algorithms and Simulation Testbed

NASA Technical Reports Server (NTRS)

Wette, Matthew; Sohl, Garett; Scharf, Daniel; Benowitz, Edward

2004-01-01

Formation flying for spacecraft is a rapidly developing field that will enable a new era of space science. For one of its missions, the Terrestrial Planet Finder (TPF) project has selected a formation flying interferometer design to detect earth-like planets orbiting distant stars. In order to advance technology needed for the TPF formation flying interferometer, the TPF project has been developing a distributed real-time testbed to demonstrate end-to-end operation of formation flying with TPF-like functionality and precision. This is the Formation Algorithms and Simulation Testbed (FAST) . This FAST was conceived to bring out issues in timing, data fusion, inter-spacecraft communication, inter-spacecraft sensing and system-wide formation robustness. In this paper we describe the FAST and show results from a two-spacecraft formation scenario. The two-spacecraft simulation is the first time that precision end-to-end formation flying operation has been demonstrated in a distributed real-time simulation environment.

Vibration signal models for fault diagnosis of planet bearings

NASA Astrophysics Data System (ADS)

Feng, Zhipeng; Ma, Haoqun; Zuo, Ming J.

2016-05-01

Rolling element bearings are key components of planetary gearboxes. Among them, the motion of planet bearings is very complex, encompassing spinning and revolution. Therefore, planet bearing vibrations are highly intricate and their fault characteristics are completely different from those of fixed-axis case, making planet bearing fault diagnosis a difficult topic. In order to address this issue, we derive the explicit equations for calculating the characteristic frequency of outer race, rolling element and inner race fault, considering the complex motion of planet bearings. We also develop the planet bearing vibration signal model for each fault case, considering the modulation effects of load zone passing, time-varying angle between the gear pair mesh and fault induced impact force, as well as the time-varying vibration transfer path. Based on the developed signal models, we derive the explicit equations of Fourier spectrum in each fault case, and summarize the vibration spectral characteristics respectively. The theoretical derivations are illustrated by numerical simulation, and further validated experimentally and all the three fault cases (i.e. outer race, rolling element and inner race localized fault) are diagnosed.

MARSIS Data Bad Time Stamp: Analysis and Solution of an Anomaly Event in a Space Mission

NASA Astrophysics Data System (ADS)

Giuppi, S.; Cartacci, M.; Cicchetti, A.; Frigeri, A.; Noschese, R.; Orosei, R.

2012-04-01

Mars Express is Europe's first spacecraft to the Red Planet. The spacecraft has been orbiting Mars since December 2003, carrying a suite of instruments that are investigating many scientific aspects of this planet in unprecedented detail. The observations are particularly focused on martian atmosphere, surface and subsurface. The most innovative instrument on board of Mars Express is MARSIS, a subsurface radar sounder with a 40-meter antenna. The main objective of MARSIS is to look for water from the martian surface down to about 5 kilometers below the surface. It provides the first opportunity to detect liquid water directly. It is also able to characterize the surface elevation, roughness, and radar reflectivity of the planet and to study the interaction of the atmosphere and solar wind in the red planet's ionosphere. MARSIS Data are stored on the on-board memory and periodically sent to Earth ground stations. Spacecraft Event Time (SCET) is the time an event occurs in relation to a spacecraft as measured by the spacecraft clock. Since it takes time for a radio transmission to reach the spacecraft from the earth, the usual operation of a spacecraft is done via an uploaded commanding script containing SCET markers to ensure a certain timeline of events. Occasionally the generation time (SCET) of the MARSIS science packets recorded during an observation gets corrupted. This means that while some of the data have the correct SCET, some other data have a SCET not compliant with the effective generation time. For this reason with the standard procedure it is possible to retrieve only partial data. In this paper we describe the cause of the anomaly occurrence and the procedures to be applied depending on the circumstances that arise. The application of these procedures is been successful and allowed to circumvent the problem.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quintana, Elisa V.; Lissauer, Jack J., E-mail: elisa.quintana@nasa.gov

Models of planet formation have shown that giant planets have a large impact on the number, masses, and orbits of terrestrial planets that form. In addition, they play an important role in delivering volatiles from material that formed exterior to the snow line (the region in the disk beyond which water ice can condense) to the inner region of the disk where terrestrial planets can maintain liquid water on their surfaces. We present simulations of the late stages of terrestrial planet formation from a disk of protoplanets around a solar-type star and we include a massive planet (from 1 Mmore » {sub ⊕} to 1 M {sub J}) in Jupiter's orbit at ∼5.2 AU in all but one set of simulations. Two initial disk models are examined with the same mass distribution and total initial water content, but with different distributions of water content. We compare the accretion rates and final water mass fraction of the planets that form. Remarkably, all of the planets that formed in our simulations without giant planets were water-rich, showing that giant planet companions are not required to deliver volatiles to terrestrial planets in the habitable zone. In contrast, an outer planet at least several times the mass of Earth may be needed to clear distant regions of debris truncating the epoch of frequent large impacts. Observations of exoplanets from radial velocity surveys suggest that outer Jupiter-like planets may be scarce, therefore, the results presented here suggest that there may be more habitable planets residing in our galaxy than previously thought.« less

Observing outer planet satellites (except Titan) with JWST: Science justification and observational requirements

USGS Publications Warehouse

Kestay, Laszlo P.; Grundy, Will; Stansberry, John; Sivaramakrishnan, Anand; Thatte, Deepashri; Gudipati, Murthy; Tsang, Constantine; Greenbaum, Alexandra; McGruder, Chima

2016-01-01

The James Webb Space Telescope (JWST) will allow observations with a unique combination of spectral, spatial, and temporal resolution for the study of outer planet satellites within our Solar System. We highlight the infrared spectroscopy of icy moons and temporal changes on geologically active satellites as two particularly valuable avenues of scientific inquiry. While some care must be taken to avoid saturation issues, JWST has observation modes that should provide excellent infrared data for such studies.

Grand Tour outer planet missions definition phase. Part 2: Minutes of meetings and official correspondence

NASA Technical Reports Server (NTRS)

Belton, M. J. S.; Aksnes, K.; Davies, M. E.; Hartmann, W. K.; Millis, R. L.; Owen, T. C.; Reilly, T. H.; Sagan, C.; Suomi, V. E.; Collins, S. A., Jr.

1972-01-01

A variety of imaging systems proposed for use aboard the Outer Planet Grand Tour Explorer are discussed and evaluated in terms of optimal resolution capability and efficient time utilization. It is pointed out that the planetary and satellite alignments at the time of encounter dictate a high degree of adaptability and versatility in order to provide sufficient image enhancement over earth-based techniques. Data compression methods are also evaluated according to the same criteria.

Twist planet drive

NASA Technical Reports Server (NTRS)

Vranish, John M. (Inventor)

1996-01-01

A planetary gear system includes a sun gear coupled to an annular ring gear through a plurality of twist-planet gears, a speeder gear, and a ground structure having an internal ring gear. Each planet gear includes a solid gear having a first half portion in the form of a spur gear which includes vertical gear teeth and a second half portion in the form of a spur gear which includes helical gear teeth that are offset from the vertical gear teeth and which contact helical gear teeth on the speeder gear and helical gear teeth on the outer ring gear. One half of the twist planet gears are preloaded downward, while the other half are preloaded upwards, each one alternating with the other so that each one twists in a motion opposite to its neighbor when rotated until each planet gear seats against the sun gear, the outer ring gear, the speeder gear, and the inner ring gear. The resulting configuration is an improved stiff anti-backlash gear system.

Hot-start Giant Planets Form with Radiative Interiors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berardo, David; Cumming, Andrew, E-mail: david.berardo@mcgill.ca, E-mail: andrew.cumming@mcgill.ca

In the hot-start core accretion formation model for gas giants, the interior of a planet is usually assumed to be fully convective. By calculating the detailed internal evolution of a planet assuming hot-start outer boundary conditions, we show that such a planet will in fact form with a radially increasing internal entropy profile, so that its interior will be radiative instead of convective. For a hot outer boundary, there is a minimum value for the entropy of the internal adiabat S {sub min} below which the accreting envelope does not match smoothly onto the interior, but instead deposits high entropymore » material onto the growing interior. One implication of this would be to at least temporarily halt the mixing of heavy elements within the planet, which are deposited by planetesimals accreted during formation. The compositional gradient this would impose could subsequently disrupt convection during post-accretion cooling, which would alter the observed cooling curve of the planet. However, even with a homogeneous composition, for which convection develops as the planet cools, the difference in cooling timescale will change the inferred mass of directly imaged gas giants.« less

Geologic Exploration of the Planets: A Personal Retrospective of the First 50 years

NASA Astrophysics Data System (ADS)

Carr, M. H.

2013-12-01

The modern era of exploration of planets and satellites beyond the Earth-Moon system began on 14 December 1962 when the Mariner 2 spacecraft flew by Venus. Since that time roughly 80 spacecraft have successfully visited other planets and their satellites. In 1962 we knew nothing of the geology of the non-terrestrial planets and satellites; they were just variously shaded discs and dots. Most of us entering the new field of planetary geology at the time did so in anticipation of the Apollo lunar landings. I was hired by Gene Shoemaker to work on lunar issues and to participate in the lunar geologic mapping program that he had initiated at the USGS. Lunar studies led naturally to planetary studies but none of us could have anticipated the geologic variety that exists within the Solar System as exemplified by the coronae of Venus, the canyons of Mars, the volcanoes of Io, the ice tectonics of Europa and Ganymede, the geysers of Enceladus and the methane-carved valleys of Titan. Although Mars appeared lunar-like in the first close-up images from the Mariner 4 (1965) and Mariners 6 and 7 (1969) fly-bys, the Mariner 9 (1971) orbiter soon revealed Mars' geologic variety. Planning imaging for Mariner 9 was challenging; aids were primitive and we essentially had a blank sheet to fill. By 1971, the Viking Project with its main objective to land on Mars and search for signs of life was well underway. In 1969 I was appointed leader of the Viking Orbiter imaging team. The main function of the cameras was to ensure that the landing sites were safe before landing. In 1976 when we acquired the first close-up images of the pre-chosen landing sites they were greeted with elation and horror, elation because of their quality, horror because of the roughness of the terrain that had seemed so smooth in the Mariner 9 images. There followed an intense period of searching for safer sites and ultimately the two landers did land safely. The search for life then followed with hopes soaring as the initial results seemed to be positive then falling as abiotic explanations of the results seemed more plausible. Meanwhile several Soviet spacecraft successfully landed on and returned images from the surface of Venus (1975, 1981), and a radar imager on Pioneer Venus (1978) gave a preview of a complex geology that was to be subsequently revealed in detail by Magellan in 1990. In 1979 attention shifted to the outer planets as the two Voyager spacecraft flew by Jupiter revealing the volcanic plumes of Io and the distinctive geology of each of the Galilean satellites. In 1978 I joined the Galileo imaging team but the mission suffered a series of mishaps and we spent almost 20 years repeatedly re-planning the Galilean satellite tour and the imaging sequences before we were rewarded in 1995 with unprecedented views of the satellites, particularly of Io's volcanoes and Europa's ice rafts. Meanwhile the Mars program had stalled. Orbiters, landers, sample returns, penetrators, networks, balloons, airplanes were all studied and restudied. After a 20 year gap, Mars exploration was successfully renewed in 1997 with Pathfinder and Global Surveyor. Failure of two Mars missions in 1999 caused another re-structuring of the program but since that time the Mars program has been remarkably successful, although we still await sample return.

InSight Spacecraft Arrival

NASA Image and Video Library

2018-02-28

At Vandenberg Air Force Base in California, NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, or InSight, spacecraft arrives at the Astrotech processing facility. InSight was developed and built by Lockheed-Martin Space Systems in Denver, Colorado, and is scheduled for liftoff is May 5, 2018. InSight is the first mission to land on Mars and explore the Red Planet's deep interior. It will investigate processes that shaped the rocky planets of the inner solar system including Earth.

Moon Shadow, Planet Shadow

NASA Image and Video Library

2010-05-12

Saturn moon Prometheus casts a narrow shadow on the rings near the much larger shadow cast by the planet in this image taken by NASA Cassini spacecraft about five months after Saturn August 2009 equinox.

First Results of the Juno Magnetometer Investigation in Jupiter's Magnetosphere

NASA Astrophysics Data System (ADS)

Connerney, Jack; Oliversen, Ronald; Espley, Jared; Kotsiaros, Stavros; Joergensen, John; Joergensen, Peter; Merano, Jose; Denver, Troelz; Benn, Mathias; Bloxham, Jeremy; Bolton, Scott; Levin, Steve

2017-04-01

The Juno spacecraft entered polar orbit about Jupiter on July 4, 2016, after a Jupiter Orbit Insertion (JOI) main engine burn lasting 35 minutes. Juno's science instruments were not powered during the critical maneuver sequence ( 5 days) but were fully operational shortly afterward. The 53.5-day capture orbit provides Juno's science instruments with the opportunity to sample the Jovian environment close up (to 1.06 Jovian radii, Rj) and in polar orbit extending to the outer reaches of the Jovian magnetosphere. Jupiter's gravity and magnetic fields will be globally mapped with unprecedented accuracy as Juno conducts a study of Jupiter's interior structure and composition, as well as the first comprehensive exploration of the polar magnetosphere. The magnetic field investigation onboard Juno is equipped with two magnetometer sensor suites, located at 10 and 12 m from the spacecraft body at the end of one of the three solar panel wings. Each contains a vector fluxgate magnetometer (FGM) sensor and a pair of co-located non-magnetic star tracker camera heads which provide accurate attitude determination for the FGM sensors. The first few periapsis passes available to date revealed an extraordinary spatial variation of the magnetic field close to the planet's surface, suggesting that Juno may be sampling the field closer to the dynamo region than widely anticipated, i.e., portending a dynamo surface extending to relatively large radial distance ( 0.9Rj?). We present the first observations of Jupiter's magnetic field obtained in close proximity to the planet, and speculate on what wonders await as more longitudes are drawn across the global map (32 polar orbits separated by <12° longitude) that the Juno mission was designed to acquire.

Characterizing Exoplanets with WFIRST

NASA Astrophysics Data System (ADS)

Robinson, Tyler D.; Stapelfeldt, Karl R.; Marley, Mark S.; Marchis, Franck; Fortney, Jonathan J.

2017-01-01

The Wide-Field Infrared Survey Telescope (WFIRST) mission is expected to be equipped with a Coronagraph Instrument (CGI) that will study and explore a diversity of exoplanets in reflected light. Beyond being a technology demonstration, the CGI will provide our first glimpses of temperate worlds around our nearest stellar neighbors. In this presentation, we explore how instrumental and astrophysical parameters will affect the ability of the WFIRST/CGI to obtain spectral and photometric observations that are useful for characterizing its planetary targets. We discuss the development of an instrument noise model suitable for studying the spectral characterization potential of a coronagraph-equipped, space-based telescope. To be consistent with planned technologies, we assume a baseline set of telescope and instrument parameters that include a 2.4 meter diameter primary aperture, an up-to-date filter set spanning the visible wavelength range, a spectroscopic wavelength range of 600-970 nm, and an instrument spectral resolution of 70. We present applications of our baseline model to a variety of spectral models of different planet types, emphasizing warm jovian exoplanets. With our exoplanet spectral models, we explore wavelength-dependent planet-star flux ratios for main sequence stars of various effective temperatures, and discuss how coronagraph inner and outer working angle constraints will influence the potential to study different types of planets. For planets most favorable to spectroscopic characterization—gas giants with extensive water vapor clouds—we study the integration times required to achieve moderate signal-to-noise ratio spectra. We also explore the sensitivity of the integration times required to detect key methane absorption bands to exozodiacal light levels. We conclude with a discussion of the opportunities for characterizing smaller, potentially rocky, worlds under a “rendezvous” scenario, where an external starshade is later paired with the WFIRST spacecraft.

Twins Image

NASA Image and Video Library

2005-08-02

NASA MESSENGER Earth flyby on Aug. 2, 2005, not only adjusted the spacecraft path to Mercury - the gravity assist maneuver allowed the spacecraft team to test several MESSENGER science instruments by observing its home planet.

The Voyager Neptune travel guide

NASA Technical Reports Server (NTRS)

Kohlhase, Charles (Editor)

1989-01-01

The Voyager mission to the giant outer planets of our solar system is described. Scientific highlights include interplanetary cruise, Jupiter, Saturn, Uranus, and their vast satellite and ring systems. Detailed plans are provided for the August 1989 Neptune encounter and subsequent interstellar journey to reach the heliopause. As background, the elements of an unmanned space mission are explained, with emphasis on the capabilities of the spacecraft and the scientific sensors. Other topics include the Voyager Grand Tour trajectory design, deep-space navigation, and gravity-assist concepts. The Neptune flyby is animated through the use of computer-generated, flip-page movie frames that appear in the corners of the publication. Useful historical information is also presented, including facts associated with the Voyager mission. Finally, short summaries are provided to describe the major objectives and schedules for several space missions planned for the remainder of the 20th century.

Design and analysis study of a spacecraft optical transceiver package

NASA Technical Reports Server (NTRS)

Lambert, S. G.

1985-01-01

A detailed system level design of an Optical Transceiver Package (OPTRANSPAC) for a deep space vehicle whose mission is outer planet exploration is developed. In addition to the terminal design, this study provides estimates of the dynamic environments to be encountered by the transceiver throughout its mission life. Optical communication link analysis, optical thin lens design, electronic functional design and mechanical layout and packaging are employed in the terminal design. Results of the study describe an Optical Transceiver Package capable of communicating to an Earth Orbiting Relay Station at a distance of 10 Astronomical Units (AU) and data rates up to 100 KBPS. The transceiver is also capable of receiving 1 KBPS of command data from the Earth Relay. The physical dimensions of the terminal are contained within a 3.5' x 1.5' x 2.0' envelope and the transceiver weight and power are estimated at 52.2 Kg (115 pounds) and 57 watts, respectively.

Technology Assessment of Doe's 55-we Stirling Technology Demonstrator Convector (TDC)

NASA Technical Reports Server (NTRS)

Furlong, Richard; Shaltens, Richard

2000-01-01

The Department of Energy (DOE), Germantown, Maryland and the NASA Glenn Research Center (GRC), Cleveland, Ohio are developing a Stirling Convertor for an advanced radioisotope power system as a potential power source for spacecraft on-board electric power for NASA deep space science missions. The Stirling Convertor is being evaluated as an alternative high efficiency power source to replace Radioisotope Thermoelectric Generators (RTGs). Stirling Technology Company (STC), Kennewick, Washington, is developing the highly efficient, long life 55-We free-piston Stirling Convertor known as the Technology Demonstrator Convertor (TDC) under contract to DOE. GRC provides Stirling technology expertise under a Space Act Agreement with the DOE. Lockheed Martin Astronautics (LMA), Valley Forge, Pennsylvania is the current power system integrator for the Advanced Radioisotope Power System (ARPS) Project for the DOE. JPL is responsible for the Outer Planets/Solar Probe Project for NASA.

Planetary science. Low-altitude magnetic field measurements by MESSENGER reveal Mercury's ancient crustal field.

PubMed

Johnson, Catherine L; Phillips, Roger J; Purucker, Michael E; Anderson, Brian J; Byrne, Paul K; Denevi, Brett W; Feinberg, Joshua M; Hauck, Steven A; Head, James W; Korth, Haje; James, Peter B; Mazarico, Erwan; Neumann, Gregory A; Philpott, Lydia C; Siegler, Matthew A; Tsyganenko, Nikolai A; Solomon, Sean C

2015-05-22

Magnetized rocks can record the history of the magnetic field of a planet, a key constraint for understanding its evolution. From orbital vector magnetic field measurements of Mercury taken by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft at altitudes below 150 kilometers, we have detected remanent magnetization in Mercury's crust. We infer a lower bound on the average age of magnetization of 3.7 to 3.9 billion years. Our findings indicate that a global magnetic field driven by dynamo processes in the fluid outer core operated early in Mercury's history. Ancient field strengths that range from those similar to Mercury's present dipole field to Earth-like values are consistent with the magnetic field observations and with the low iron content of Mercury's crust inferred from MESSENGER elemental composition data. Copyright © 2015, American Association for the Advancement of Science.

Nuclear Power in Space

DOE R&D Accomplishments Database

1994-01-01

In the early years of the United States space program, lightweight batteries, fuel cells, and solar modules provided electric power for space missions. As missions became more ambitious and complex, power needs increased and scientists investigated various options to meet these challenging power requirements. One of the options was nuclear energy. By the mid-1950s, research had begun in earnest on ways to use nuclear power in space. These efforts resulted in the first radioisotope thermoelectric generators (RTGs), which are nuclear power generators build specifically for space and special terrestrial uses. These RTGs convert the heat generated from the natural decay of their radioactive fuel into electricity. RTGs have powered many spacecraft used for exploring the outer planets of the solar system and orbiting the sun and Earth. They have also landed on Mars and the moon. They provide the power that enables us to see and learn about even the farthermost objects in our solar system.

Attitude propulsion technology for TOPS

NASA Technical Reports Server (NTRS)

Moynihan, P. I.

1972-01-01

The thermoelectric outer planet spacecraft (TOPS) attitude propulsion subsystem (APS) effort is discussed. It includes the tradeoff rationale that went into the selection of an anhydrous hydrazine baseline system, followed by a discussion of the 0.22 N thruster and its integration into a portable, self-contained propulsion module that was designed, developed, and man rated to support the TOPS single-axis attitude control tests. The results of a cold-start feasibility demonstration with a modified thruster are presented. A description of three types of 0.44 thrusters that were procured for in-house evaluation is included along with the results of the test program. This is followed by a description of the APS feed system components, their evaluations, and a discussion of an evaluation of elastomeric material for valve seat seals. A list of new technology items which will be of value for application to future systems of this type is included.

The mass of the Mars-sized exoplanet Kepler-138 b from transit timing.

PubMed

Jontof-Hutter, Daniel; Rowe, Jason F; Lissauer, Jack J; Fabrycky, Daniel C; Ford, Eric B

2015-06-18

Extrasolar planets that pass in front of their host star (transit) cause a temporary decrease in the apparent brightness of the star, providing a direct measure of the planet's size and orbital period. In some systems with multiple transiting planets, the times of the transits are measurably affected by the gravitational interactions between neighbouring planets. In favourable cases, the departures from Keplerian orbits (that is, unaffected by gravitational effects) implied by the observed transit times permit the planetary masses to be measured, which is key to determining their bulk densities. Characterizing rocky planets is particularly difficult, because they are generally smaller and less massive than gaseous planets. Therefore, few exoplanets near the size of Earth have had their masses measured. Here we report the sizes and masses of three planets orbiting Kepler-138, a star much fainter and cooler than the Sun. We determine that the mass of the Mars-sized inner planet, Kepler-138 b, is 0.066(+0.059)(-0.037) Earth masses. Its density is 2.6(+2.4)(-1.5) grams per cubic centimetre. The middle and outer planets are both slightly larger than Earth. The middle planet's density (6.2(+5.8)(-3.4) grams per cubic centimetre) is similar to that of Earth, and the outer planet is less than half as dense at 2.1(+2.2)(-1.2) grams per cubic centimetre, implying that it contains a greater portion of low-density components such as water and hydrogen.

On Mars: Exploration of the Red Planet, 1958 - 1978

NASA Technical Reports Server (NTRS)

Ezell, E. C. (Editor); Ezell, L. N. (Editor)

1984-01-01

The exploration of Mars is covered by the following topics: Mariner spacecraft and launch vehicles, search for Martian life; Voyager spacecraft; creation of Viking; Viking Orbiter and its Mariner inheritance; Viking lander; building a complex spacecraft; selecting landing sites; site certification, and data from Mars.

Earth-type planets (Mercury, Venus, and Mars)

NASA Technical Reports Server (NTRS)

Marov, M. Y.; Davydov, V. D.

1975-01-01

Spacecraft- and Earth-based studies on the physical nature of the planets Mercury, Venus, and Mars are reported. Charts and graphs are presented on planetary surface properties, rotational parameters, atmospheric compositions, and astronomical characteristics.

Circles on Saturn

NASA Image and Video Library

2014-04-14

Saturn winds race furiously around the planet, blowing at high speeds which form distinct belts and zones which encircle the planet pole, as well as its famous hexagon as seen in this image from NASA Cassini spacecraft.

Magnetospheres of the outer planets

NASA Technical Reports Server (NTRS)

Vanallen, James A.

1987-01-01

The five qualitatively different types of magnetism that a planet body can exhibit are outlined. Potential sources of energetic particles in a planetary magnetosphere are discussed. The magnetosphere of Uranus and Neptune are then described using Pioneer 10 data.

Planetary Atmospheres and the Search for Life.

ERIC Educational Resources Information Center

Owen, Tobias

1982-01-01

Different ways in which the atmospheres of different planets have originated and evolved are discussed. Includes tables on the atmospheric composition of: (1) Earth; (2) Mars; (3) Venus; (4)Titan (Saturn's Satellite); and (5) the outer planets. (SK)

Employment of Asteroids for Movement Space Ship and Probes

NASA Technical Reports Server (NTRS)

Bolonkin, Alexander

2002-01-01

At present, rockets are used to change the trajectory of space ships and probes. This method is very expensive and requires a lot of fuel, which limits the feasibility of space stations, interplanetary space ships, and probes. Sometimes space probes use the gravity field of a planet. However, there are only 9 planets in our solar system and they are separated by great distances. There are tens of millions of asteroids in outer space. The author offers a revolutionary method for changing the trajectory of space probes. This method uses the kinetic or rotary energy of asteroids, meteorites or other space bodies (small planets, natural planet satellites, etc.). to increase (to decrease) ship (probe) speed up to 1000 m/sec (or more) and to get any new direction in outer space. The flight possibilities of space ships and probes are increased by a factor of millions.

The planets Uranus, Neptune, and Pluto (1971)

NASA Technical Reports Server (NTRS)

Palluconi, F. D.

1972-01-01

Design criteria relating to spacecraft intended to investigate the planets of Uranus, Neptune, and Pluto are presented. Assessments were made of the potential effects of environmental properties on vehicle performance. Pertinent data on the mass, radius, shape, mean density, rotational pole location, and mean orbital elements for the three planets are given in graphs and tables.

Debris disks as signposts of terrestrial planet formation

NASA Astrophysics Data System (ADS)

Raymond, S. N.; Armitage, P. J.; Moro-Martín, A.; Booth, M.; Wyatt, M. C.; Armstrong, J. C.; Mandell, A. M.; Selsis, F.; West, A. A.

2011-06-01

There exists strong circumstantial evidence from their eccentric orbits that most of the known extra-solar planetary systems are the survivors of violent dynamical instabilities. Here we explore the effect of giant planet instabilities on the formation and survival of terrestrial planets. We numerically simulate the evolution of planetary systems around Sun-like stars that include three components: (i) an inner disk of planetesimals and planetary embryos; (ii) three giant planets at Jupiter-Saturn distances; and (iii) an outer disk of planetesimals comparable to estimates of the primitive Kuiper belt. We calculate the dust production and spectral energy distribution of each system by assuming that each planetesimal particle represents an ensemble of smaller bodies in collisional equilibrium. Our main result is a strong correlation between the evolution of the inner and outer parts of planetary systems, i.e. between the presence of terrestrial planets and debris disks. Strong giant planet instabilities - that produce very eccentric surviving planets - destroy all rocky material in the system, including fully-formed terrestrial planets if the instabilities occur late, and also destroy the icy planetesimal population. Stable or weakly unstable systems allow terrestrial planets to accrete in their inner regions and significant dust to be produced in their outer regions, detectable at mid-infrared wavelengths as debris disks. Stars older than ~100 Myr with bright cold dust emission (in particular at λ ~ 70 μm) signpost dynamically calm environments that were conducive to efficient terrestrial accretion. Such emission is present around ~16% of billion-year old Solar-type stars. Our simulations yield numerous secondary results: 1) the typical eccentricities of as-yet undetected terrestrial planets are ~0.1 but there exists a novel class of terrestrial planet system whose single planet undergoes large amplitude oscillations in orbital eccentricity and inclination; 2) by scaling our systems to match the observed semimajor axis distribution of giant exoplanets, we predict that terrestrial exoplanets in the same systems should be a few times more abundant at ~0.5 AU than giant or terrestrial exoplanets at 1 AU; 3) the Solar System appears to be unusual in terms of its combination of a rich terrestrial planet system and a low dust content. This may be explained by the weak, outward-directed instability that is thought to have caused the late heavy bombardment. The movie associated to Fig. 2 is available in electronic form at http://www.aanda.org

Deep Space 1 Ion Engine Completed a 3-Year Journey

NASA Technical Reports Server (NTRS)

Sovey, James S.; Patterson, Michael J.; Rawlin, Vincent K.; Hamley, John A.

2001-01-01

A xenon ion engine and power processor system, which was developed by the NASA Glenn Research Center in partnership with the Jet Propulsion Laboratory and Boeing Electron Dynamic Devices, completed nearly 3 years of operation aboard the Deep Space 1 spacecraft. The 2.3-kW ion engine, which provided primary propulsion and two-axis attitude control, thrusted for more than 16,000 hr and consumed more than 70 kg of xenon propellant. The Deep Space 1 spacecraft was launched on October 24, 1998, to validate 12 futuristic technologies, including the ion-propulsion system. After the technology validation process was successfully completed, the Deep Space 1 spacecraft flew by the small asteroid Braille on July 29, 1999. The final objective of this mission was to encounter the active comet Borrelly, which is about 6 miles long. The ion engine was on a thrusting schedule to navigate the Deep Space 1 spacecraft to within 1400 miles of the comet. Since the hydrazine used for spacecraft attitude control was in short supply, the ion engine also provided two-axis attitude control to conserve the hydrazine supply for the Borrelly encounter. The comet encounter took place on September 22, 2001. Dr. Marc Rayman, project manager of Deep Space 1 at the Jet Propulsion Laboratory said, "Deep Space 1 plunged into the heart of the comet Borrelly and has lived to tell every detail of its spinetingling adventure! The images are even better than the impressive images of comet Halley taken by Europe's Giotto spacecraft in 1986." The Deep Space 1 mission, which successfully tested the 12 high-risk, advanced technologies and captured the best images ever taken of a comet, was voluntarily terminated on December 18, 2001. The successful demonstration of the 2-kW-class ion propulsion system technology is now providing mission planners with off-the-shelf flight hardware. Higher power, next generation ion propulsion systems are being developed for large flagship missions, such as outer planet explorers and sample-return missions.

Adhesion in a Vacuum Environment and its Implications for Dust Mitigation Techniques on Airless Bodies

NASA Technical Reports Server (NTRS)

Berkebile, Stephen; Gaier, James R.

2012-01-01

During the Apollo missions, the adhesion of dust to critical spacecraft systems was a greater problem than anticipated and resulted in functional degradation of thermal control surfaces, spacesuit seals, and other spacecraft components. Notably, Earth-based simulation efforts did not predict the magnitude and effects of dust adhesion in the lunar environment. Forty years later, we understand that the ultrahigh vacuum (UHV) environment, coupled with micrometeorite impacts and constant ion and photon bombardment from the sun result in atomically clean and high surface energy dust particles and spacecraft surfaces. However, both the dominant mechanism of adhesion in airless environments and the conditions for high fidelity simulation tests have still to be determined. The experiments presented in here aim to aid in the development of dust mitigation techniques for airless bodies (e.g., lunar surface, asteroids, moons of outer planets). The approach taken consists of (a) quantifying the adhesion between common polymer and metallic spacecraft materials and a synthetic noritic volcanic glass, as a function of surface cleanliness and of triboelectric charge transfer in a UHV environment, and (b) determining parameters for high fidelity tests through investigation of adhesion dependence on vacuum environment and sample treatment. Adhesion force has been measured between pins of spacecraft materials and a plate of synthetic volcanic glass by determining the pull-off force with a torsion balance. Although no significant adhesion is generally observed directly as a result of high surface energies, the adhesion due to induced electrostatic charge is observed to increase with spacecraft material cleanliness, in some cases by over a factor of 10. Furthermore, electrostatically-induced adhesion is found to decrease rapidly above pressures of 10-6 torr. It is concluded that high-fidelity tests should be conducted in high to ultrahigh vacuum and include an ionized surface cleaning process.

Optimization of extended propulsion time nuclear-electric propulsion trajectories

NASA Technical Reports Server (NTRS)

Sauer, C. G., Jr.

1981-01-01

This paper presents the methodology used in optimizing extended propulsion time NEP missions considering realistic thruster lifetime constraints. These missions consist of a powered spiral escape from a 700-km circular orbit at the earth, followed by a powered heliocentric transfer with an optimized coast phase, and terminating in a spiral capture phase at the target planet. This analysis is most applicable to those missions with very high energy requirements such as outer planet orbiter missions or sample return missions where the total propulsion time could greatly exceed the expected lifetime of an individual thruster. This methodology has been applied to the investigation of NEP missions to the outer planets where examples are presented of both constrained and optimized trajectories.

Planetary size comparisons: A photographic study

NASA Technical Reports Server (NTRS)

Meszaros, S. P.

1983-01-01

Over the past two decades NASA spacecraft missions obtained photographs permitting accurate size measurements of the planets and moons, and their surface features. Planetary global views are displayed at the same scale, in each picture to allow visual size comparisons. Additionally, special geographical features on some of the planets are compared with selected Earth areas, again at the same scale. Artist renderings and estimated sizes are used for worlds not yet reached by spacecraft. Included with each picture is number designation for use in ordering copies of the photos.

InSight Spacecraft Arrival

NASA Image and Video Library

2018-02-28

After a U.S. Air Force C-17 aircraft arrived at Vandenberg Air Force Base in California, ground crews offload NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, or InSight, spacecraft designed to land on Mars. InSight was developed and built by Lockheed-Martin Space Systems in Denver, Colorado, and is scheduled for liftoff is May 5, 2018. InSight is the first mission to explore the Red Planet's deep interior. It will investigate processes that shaped the rocky planets of the inner solar system including Earth.

InSight Spacecraft Uncrating, Removal from Container, Lift Heat

NASA Image and Video Library

2018-03-01

At Vandenberg Air Force Base in California, NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, or InSight, spacecraft is uncrated inside the Astrotech processing facility. InSight was developed and built by Lockheed-Martin Space Systems in Denver, Colorado, and is scheduled for liftoff is May 5, 2018. InSight is the first mission to land on Mars and explore the Red Planet's deep interior. It will investigate processes that shaped the rocky planets of the inner solar system including Earth.

InSight Spacecraft Arrival

NASA Image and Video Library

2018-02-28

A U.S. Air Force C-17 aircraft arrives at Vandenberg Air Force Base in California carrying NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, or InSight, spacecraft designed to land on Mars. InSight was developed and built by Lockheed-Martin Space Systems in Denver, Colorado, and is scheduled for liftoff is May 5, 2018. InSight is the first mission to explore the Red Planet's deep interior. It will investigate processes that shaped the rocky planets of the inner solar system including Earth.

Dwarfed by Gas Giant

NASA Image and Video Library

2011-06-06

Two moons, Rhea and Dione, join the planet and its rings in this view from NASA Cassini spacecraft. Rhea and Dione are respectively the second and fourth largest moons of Saturn, but they are tiny compared to the planet.

The Whole Heliosphere Interval: Campaign Summaries and Early Results

NASA Technical Reports Server (NTRS)

Thompson, Barbara J.; Gibson, Sarah E.; Kozyra, Janet U.

2008-01-01

The Whole Heliosphere Interval (WHI) is an internationally coordinated observing and modeling effort to characterize the 3-dimensional interconnected solar-heliospheric-planetary system - a.k.a. the "heliophysical" system. The heart of the WHI campaign is the study of the interconnected 3-D heliophysical domain, from the interior of the Sun, to the Earth, outer planets, and into interstellar space. WHI observing campaigns began with the 3-0 solar structure from solar Carrington Rotation 2068, which ran from March 20 - April 16, 2008. Observations and models of the outer heliosphere and planetary impacts extended beyond those dates as necessary; for example, the solar wind transit time to outer planets can take months. WHI occurs during solar minimum, which optimizes our ability to characterize the 3-D heliosphere and trace the structure to the outer limits of the heliosphere. A summary of some of the key results from the WHI first workshop in August 2008 will be given.

Closing in on Jupiter North Pole

NASA Image and Video Library

2016-09-02

As NASA's Juno spacecraft closed in on Jupiter for its Aug. 27, 2016 pass, its view grew sharper and fine details in the north polar region became increasingly visible. The JunoCam instrument obtained this view on August 27, about two hours before closest approach, when the spacecraft was 120,000 miles (195,000 kilometers) away from the giant planet (i.e., for Jupiter's center). Unlike the equatorial region's familiar structure of belts and zones, the poles are mottled with rotating storms of various sizes, similar to giant versions of terrestrial hurricanes. Jupiter's poles have not been seen from this perspective since the Pioneer 11 spacecraft flew by the planet in 1974. http://photojournal.jpl.nasa.gov/catalog/PIA21030

Initial Assessment of a Rapid Method of Calculating CEV Environmental Heating

NASA Technical Reports Server (NTRS)

Pickney, John T.; Milliken, Andrew H.

2010-01-01

An innovative method for rapidly calculating spacecraft environmental absorbed heats in planetary orbit is described. The method employs reading a database of pre-calculated orbital absorbed heats and adjusting those heats for desired orbit parameters. The approach differs from traditional Monte Carlo methods that are orbit based with a planet centered coordinate system. The database is based on a spacecraft centered coordinated system where the range of all possible sun and planet look angles are evaluated. In an example case 37,044 orbit configurations were analyzed for average orbital heats on selected spacecraft surfaces. Calculation time was under 2 minutes while a comparable Monte Carlo evaluation would have taken an estimated 26 hours

Sequential planet formation in transition disks: The case of HD 100546

NASA Astrophysics Data System (ADS)

Pinilla, Paola; Birnsitel, Til; Walsh, Catherine; van Dishoeck, Ewine

2015-08-01

Transition disks are circumstellar disks with dust inner cavities and may reveal an intermediate step of the ongoing disk dispersal process, where planet formation might happen. The recent gas and dust observations of transition disks have given major support to the presence of massive planets in transition disks. The analysis of such observations help to constrain the properties of the potential unseen planets. An excellent candidate to analyse the dust evolution when planets are embedded in disks is the transition disk around the Herbig Ae star HD 100546. Near-infrared observations of HD 100546 suggested the presence on an inner planet at 10 AU distance from the star (e.g. Mulders et al. 2013), while an outer planet has been directly imaged at 70 AU distance, which may be in the act of formation (Quant et al. 2013, 2015; Currie et al. 2014). The two embedded planets can lead to remarkable dust structures due to the particle trapping at the edges of the gaps caved by such planets (e.g. Pinilla et al. 2012, 2015). Recent ALMA Cycle 0 observations of this disk reveal a two-ring like structure consistent with particle trapping induced by the two companions (Walsh et al. 2014). The comparison of these observations with dust evolution models, that include the coagulation and fragmentation of dust grains, suggest that the outer companion must be at least two million of years younger than the inner companion, revealing sequential planet formation in this disk (Pinilla et al. 2015, under revision).

ALMA continuum observations of the protoplanetary disk AS 209. Evidence of multiple gaps opened by a single planet

NASA Astrophysics Data System (ADS)

Fedele, D.; Tazzari, M.; Booth, R.; Testi, L.; Clarke, C. J.; Pascucci, I.; Kospal, A.; Semenov, D.; Bruderer, S.; Henning, Th.; Teague, R.

2018-02-01

This paper presents new high angular resolution ALMA 1.3 mm dust continuum observations of the protoplanetary system AS 209 in the Ophiuchus star forming region. The dust continuum emission is characterized by a main central core and two prominent rings at r = 75 au and r = 130 au intervaled by two gaps at r = 62 au and r = 103 au. The two gaps have different widths and depths, with the inner one being narrower and shallower. We determined the surface density of the millimeter dust grains using the 3D radiative transfer disk code DALI. According to our fiducial model the inner gap is partially filled with millimeter grains while the outer gap is largely devoid of dust. The inferred surface density is compared to 3D hydrodynamical simulations (FARGO-3D) of planet-disk interaction. The outer dust gap is consistent with the presence of a giant planet (Mplanet 0.7 MSaturn); the planet is responsible for the gap opening and for the pile-up of dust at the outer edge of the planet orbit. The simulations also show that the same planet could be the origin of the inner gap at r = 62 au. The relative position of the two dust gaps is close to the 2:1 resonance and we have investigated the possibility of a second planet inside the inner gap. The resulting surface density (including location, width and depth of the two dust gaps) are in agreement with the observations. The properties of the inner gap pose a strong constraint to the mass of the inner planet (Mplanet < 0.1 MJ). In both scenarios (single or pair of planets), the hydrodynamical simulations suggest a very low disk viscosity (α < 10‑4). Given the young age of the system (0.5-1 Myr), this result implies that the formation of giant planets occurs on a timescale of ≲1 Myr. The reduced image (FITS file) is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/610/A24

Relative Sensor with 4(pi) Coverage for Formation Flying Missions

NASA Technical Reports Server (NTRS)

Tien, Jeffrey Y.; Purcell, George H., Jr.; Sirinivasan, Jeffrey M.; Young, Lawrence E.

2004-01-01

The Terrestrial Planet Finder (TPF) pre-project, an element of NASA's Origins program, is currently developing two architectures for a mission to search for earth-like planets around nearby stars. One of the architectures being developed is the Formation Flying Interferometer (FFI). The FFI is envisioned to consist of up to seven spacecraft (as many as six 'collectors' with IR telescopes, and a 'combiner') flying in precise formation within f 1 cm of pre-determined trajectories for synchronized observations. The spacecraft-to-spacecraft separations are variable between 20 m and 100 m or more during observations to support various configurations of the interferometer in the planet-finding mode. The challenges involved with TPF autonomous operations, ranging from formation acquisition and formation maneuvering to high precision formation control during science observations, are unprecedented. In this paper we discuss the development of the formation acquisition sensor, which uses novel modulation and duplexing schemes to enable fast signal acquisition, multiple-spacecraft operation, and mitigation of inherent jamming conditions, while providing precise formation sensing and integrated radar capability. This approach performs delay synthesis and carrier cycle ambiguity resolution to improve range measurement, and uses differential carrier cycle ambiguity resolution to make precise bearing angle measurements without calibration maneuvers.

Relative Sensor with 4Pi Coverage for Formation Flying Missions

NASA Technical Reports Server (NTRS)

Tien, Jeffrey Y.; Purcell, George H., Jr.; Srinivasan, Jeffrey M.; Young, Lawrence E.

2004-01-01

The Terrestrial Planet Finder (TPF) pre-project, an element of NASA s Origins program, is currently developing two architectures for a mission to search for earth-like planets around nearby stars. One of the architectures being developed is the Formation Flying Interferometer (FFI). The FFI is envisioned to consist of up to seven spacecraft (as many as six "collectors" with IR telescopes, and a "combiner") flying in precise formation within +/-1 cm of pre-determined trajectories for synchronized observations. The spacecraft-to-spacecraft separations are variable between 20 m and 100 m or more during observations to support various configurations of the interferometer in the planet-finding mode. The challenges involved with TPF autonomous operations, ranging from formation acquisition and formation maneuvering to high precision formation control during science observations, are unprecedented. In this paper we discuss the development of the formation acquisition sensor, which uses novel modulation and duplexing schemes to enable fast signal acquisition, multiple-spacecraft operation, and mitigation of inherent jamming conditions, while providing precise formation sensing and integrated radar capability. This approach performs delay synthesis and carrier cycle ambiguity resolution to improve range measurement, and uses differential carrier cycle ambiguity resolution to make precise bearing angle measurements without calibration maneuvers.

Factors Influencing Solar Electric Propulsion Vehicle Payload Delivery for Outer Planet Missions

NASA Technical Reports Server (NTRS)

Cupples, Michael; Green, Shaun; Coverstone, Victoria

2003-01-01

Systems analyses were performed for missions utilizing solar electric propulsion systems to deliver payloads to outer-planet destinations. A range of mission and systems factors and their affect on the delivery capability of the solar electric propulsion system was examined. The effect of varying the destination, the trip time, the launch vehicle, and gravity-assist boundary conditions was investigated. In addition, the affects of selecting propulsion system and power systems characteristics (including primary array power variation, number of thrusters, thruster throttling mode, and thruster Isp) on delivered payload was examined.

A propagation tool to connect remote-sensing observations with in-situ measurements of heliospheric structures

NASA Astrophysics Data System (ADS)

Rouillard, A. P.; Lavraud, B.; Génot, V.; Bouchemit, M.; Dufourg, N.; Plotnikov, I.; Pinto, R. F.; Sanchez-Diaz, E.; Lavarra, M.; Penou, M.; Jacquey, C.; André, N.; Caussarieu, S.; Toniutti, J.-P.; Popescu, D.; Buchlin, E.; Caminade, S.; Alingery, P.; Davies, J. A.; Odstrcil, D.; Mays, L.

2017-11-01

The remoteness of the Sun and the harsh conditions prevailing in the solar corona have so far limited the observational data used in the study of solar physics to remote-sensing observations taken either from the ground or from space. In contrast, the 'solar wind laboratory' is directly measured in situ by a fleet of spacecraft measuring the properties of the plasma and magnetic fields at specific points in space. Since 2007, the solar-terrestrial relations observatory (STEREO) has been providing images of the solar wind that flows between the solar corona and spacecraft making in-situ measurements. This has allowed scientists to directly connect processes imaged near the Sun with the subsequent effects measured in the solar wind. This new capability prompted the development of a series of tools and techniques to track heliospheric structures through space. This article presents one of these tools, a web-based interface called the 'Propagation Tool' that offers an integrated research environment to study the evolution of coronal and solar wind structures, such as Coronal Mass Ejections (CMEs), Corotating Interaction Regions (CIRs) and Solar Energetic Particles (SEPs). These structures can be propagated from the Sun outwards to or alternatively inwards from planets and spacecraft situated in the inner and outer heliosphere. In this paper, we present the global architecture of the tool, discuss some of the assumptions made to simulate the evolution of the structures and show how the tool connects to different databases.

Jupiter's Swirling South Pole

NASA Image and Video Library

2018-01-18

This image of Jupiter's swirling south polar region was captured by NASA's Juno spacecraft as it neared completion of its tenth close flyby of the gas giant planet. The "empty" space above and below Jupiter in this color-enhanced image can trick the mind, causing the viewer to perceive our solar system's largest planet as less colossal than it is. In reality, Jupiter is wide enough to fit 11 Earths across its clouded disk. The spacecraft captured this image on Dec. 16, 2017, at 11:07 PST (2:07 p.m. EST) when the spacecraft was about 64,899 miles (104,446 kilometers) from the tops of the clouds of the planet at a latitude of 83.9 degrees south -- almost directly over Jupiter's south pole. The spatial scale in this image is 43.6 miles/pixel (70.2 kilometers/pixel). Citizen scientist Gerald Eichstädt processed this image using data from the JunoCam imager. https://photojournal.jpl.nasa.gov/catalog/PIA21975

The Mars Climate Orbiter arrives at KSC to begin final preparations for launch

NASA Technical Reports Server (NTRS)

1998-01-01

The Mars Climate Orbiter spacecraft arrives at KSC's Shuttle Landing Facility aboard an Air Force C-17 cargo plane early this morning following its flight from the Lockheed Martin Astronautics plant in Denver, Colo. When the spacecraft arrives at the red planet, it will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (1.8 Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Delta II 7425 rocket.

KSC-98pc1048

NASA Image and Video Library

1998-09-11

The Mars Climate Orbiter spacecraft is moved into the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2) in KSC's industrial area. It arrived at the Shuttle Landing Facility aboard an Air Force C-17 cargo plane early this morning following its flight from the Lockheed Martin Astronautics plant in Denver, Colo. When it arrives at the red planet, the Mars Climate Orbiter will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (1.8 Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Delta II 7425 rocket

KSC-98pc1047

NASA Image and Video Library

1998-09-11

The Mars Climate Orbiter spacecraft is moved onto a flatbed for transport to the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2). It arrived at KSC's Shuttle Landing Facility aboard an Air Force C-17 cargo plane early this morning following its flight from the Lockheed Martin Astronautics plant in Denver, Colo. When it arrives at the red planet, the Mars Climate Orbiter will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (1.8 Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Delta II 7425 rocket

Atmospheric Mining in the Outer Solar System:. [Aerial Vehicle Reconnaissance and Exploration Options

NASA Technical Reports Server (NTRS)

Palaszewski, Bryan A.

2014-01-01

Atmospheric mining in the outer solar system has been investigated as a means of fuel production for high energy propulsion and power. Fusion fuels such as Helium 3 (3He) and hydrogen can be wrested from the atmospheres of Uranus and Neptune and either returned to Earth or used in-situ for energy production. Helium 3 and hydrogen (deuterium, etc.) were the primary gases of interest with hydrogen being the primary propellant for nuclear thermal solid core and gas core rocket-based atmospheric flight. A series of analyses were undertaken to investigate resource capturing aspects of atmospheric mining in the outer solar system. This included the gas capturing rate, storage options, and different methods of direct use of the captured gases. Additional supporting analyses were conducted to illuminate vehicle sizing and orbital transportation issues. While capturing 3He, large amounts of hydrogen and 4He are produced. With these two additional gases, the potential for fueling small and large fleets of additional exploration and exploitation vehicles exists. Additional aerospacecraft or other aerial vehicles (UAVs, balloons, rockets, etc.) could fly through the outer planet atmospheres, for global weather observations, localized storm or other disturbance investigations, wind speed measurements, polar observations, etc. Deep-diving aircraft (built with the strength to withstand many atmospheres of pressure) powered by the excess hydrogen or helium 4 may be designed to probe the higher density regions of the gas giants. Outer planet atmospheric properties, atmospheric storm data, and mission planning for future outer planet UAVs are presented.

Initial pioneer venus magnetic field results: dayside observations.

PubMed

Russell, C T; Elphic, R C; Slavin, J A

1979-02-23

Initial observations by the Pioneer Venus mangnetometer in the sunlit ionosphere reveal a dynamic ionosphere, very responsive to external solar-wind conditions. The localtions of the bow shock and ionosphere are variable. The strength of the magnetic field just olutside the ionopause is in approximate pressure balance with the thermal plasma of the ionosphere and changes markedly from day, to day in response to changes in solar wind pressure. The field strength in the ionosphere is also variable from day to day. The field is often weak, at most a few gammas, but reaching many tens of gammas for periods of the order of seconds. These field enchantments are interpreted as due to the passage of spacecraft through flux ropes consisting of bundles of twisted field lines surrounded by the ionospheric plasma. The helicity of the flux varies through the flux tube, with lows pitch angles on the inside and very lage angles in the low-field outer edges of the ropes. These ropes may have external or internal sources. Consistent with previous results, the average position of the bow shock is much closer to the planet than would be expected if the solar wnd were completely deflected by the planet. In total, these observations indicate that the solar wind plays a significant role in the physics of the Venus ionosphere.

Reborn Kepler Discovers First K2 Exoplanet Artist Concept

NASA Image and Video Library

2014-12-18

This artist concept shows NASA planet-hunting Kepler spacecraft operating in a new mission profile called K2. Using publicly available data, astronomers have confirmed K2 first exoplanet discovery proving Kepler can still find planets.

Status and future of extraterrestrial mapping programs

NASA Technical Reports Server (NTRS)

Batson, R. M.

1981-01-01

Extensive mapping programs have been completed for the Earth's Moon and for the planet Mercury. Mars, Venus, and the Galilean satellites of Jupiter (Io, Europa, Ganymede, and Callisto), are currently being mapped. The two Voyager spacecraft are expected to return data from which maps can be made of as many as six of the satellites of Saturn and two or more of the satellites of Uranus. The standard reconnaissance mapping scales used for the planets are 1:25,000,000 and 1:5,000,000; where resolution of data warrants, maps are compiled at the larger scales of 1:2,000,000, 1:1,000,000 and 1:250,000. Planimetric maps of a particular planet are compiled first. The first spacecraft to visit a planet is not designed to return data from which elevations can be determined. As exploration becomes more intensive, more sophisticated missions return photogrammetric and other data to permit compilation of contour maps.

Scattering of exocomets by a planet chain: exozodi levels and the delivery of cometary material to inner planets

NASA Astrophysics Data System (ADS)

Marino, Sebastian; Bonsor, Amy; Wyatt, Mark C.; Kral, Quentin

2018-06-01

Exocomets scattered by planets have been invoked to explain observations in multiple contexts, including the frequently found near- and mid-infrared excess around nearby stars arising from exozodiacal dust. Here we investigate how the process of inward scattering of comets originating in an outer belt, is affected by the architecture of a planetary system, to determine whether this could lead to observable exozodi levels or deliver volatiles to inner planets. Using N-body simulations, we model systems with different planet mass and orbital spacing distributions in the 1-50 AU region. We find that tightly packed (Δap < 20RH, m) low mass planets are the most efficient at delivering material to exozodi regions (5-7% of scattered exocomets end up within 0.5 AU at some point), although the exozodi levels do not vary by more than a factor of ˜7 for the architectures studied here. We suggest that emission from scattered dusty material in between the planets could provide a potential test for this delivery mechanism. We show that the surface density of scattered material can vary by two orders of magnitude (being highest for systems of low mass planets with medium spacing), whilst the exozodi delivery rate stays roughly constant, and that future instruments such as JWST could detect it. In fact for η Corvi, the current Herschel upper limit rules our the scattering scenario by a chain of ≲30 M⊕ planets. Finally, we show that exocomets could be efficient at delivering cometary material to inner planets (0.1-1% of scattered comets are accreted per inner planet). Overall, the best systems at delivering comets to inner planets are the ones that have low mass outer planets and medium spacing (˜20RH, m).

Development of Conception of Creation of Duty Spacecraft in Systems to Warn of Disasters

NASA Astrophysics Data System (ADS)

Konyukhov, S.; Slyunyayev, M.

The possibility to probe the outer space from the point remote from the Earth as well as the inspection of the planet as a whole and its environment essentially influences on the time of detecting the changes of the environmental parameters, which are dangerous to people. The actuality of problem to warn of the threatening disasters is obvious. There can be no doubt that the spacecraft play the important part in the systems to warn of disasters. Presented in the report is the development of conception on creation of the "duty" spacecraft in links of systems to warn of disasters. For the first time the possibility is discussed not only to detect the early signs of the impending disaster but also to quickly deliver the means of rescuing the people to the dangerous area. Presented is the technical configuration of the "duty" spacecraft in which new design solutions were used. In particular, the spacecraft may include the capsules-leaders with small dimensions and the module-rescuer with big sizes which is able to fulfill the atmospheric re-entry and the controlled flight in atmosphere. Shown is the possibility to increase the total impulse of the onboard power plant, in comparison with the versions being in operation, with keeping the mass and dimension limitations. Proposed is the experiment to determine the level of the power loss as well as the consumption of the power carrier during the every cycle if the power carrier is used many times within spacecraft. Presented is the interface between the versions of new "duty" spacecraft and the launch vehicles which are in operation at present. Proposed for the first time is the scheme of the informative interaction of the capsules-leaders to be sent beforehand to the potentially dangerous area with the "duty" spacecraft and with the module- rescuer entering into the atmosphere. The report proposes to discuss the issue about the theoretical possibility to influence on the processes of arising and the early phase of the tornado development by means of the outer artificial influence. With this aspect the capsules-leaders may serve as the means to guide the module with big sizes to the chosen area of the arising tornado. The module is able to pulverize in this area the several tons of compound which actively absorbs the moisture and water drops. The interaction of the tornado jets with the compound absorbing the moisture hypothetically is able to influence on the process of arising the tornado or on the trajectory of its motion. However, this hypothesis requires the quantitative analysis of its effectiveness. The authors hope to continue the study of this issue and will be grateful to colleagues for the exchange of information and the wish to enlarge the circle of investigators of this problem.

Mercury: Beethoven Quadrangle, H-7

NASA Image and Video Library

2000-04-01

This image, from NASA Mariner 10 spacecraft which launched in 1974, is of the H-7 Beethoven Quadrangle, and lies in Mercury Equatorial Mercator. NASA Mariner 10 spacecraft imaged the region during its initial flyby of the planet.

On the Way to Ceres Artist Concept

NASA Image and Video Library

2013-12-03

This artist concept shows NASA Dawn spacecraft heading toward the dwarf planet Ceres. When Dawn arrives, it will be the first spacecraft to go into orbit around two destinations in our solar system beyond Earth.

Core Formation Process and Light Elements in the Planetary Core

NASA Astrophysics Data System (ADS)

Ohtani, E.; Sakairi, T.; Watanabe, K.; Kamada, S.; Sakamaki, T.; Hirao, N.

2015-12-01

Si, O, and S are major candidates for light elements in the planetary core. In the early stage of the planetary formation, the core formation started by percolation of the metallic liquid though silicate matrix because Fe-S-O and Fe-S-Si eutectic temperatures are significantly lower than the solidus of the silicates. Therefore, in the early stage of accretion of the planets, the eutectic liquid with S enrichment was formed and separated into the core by percolation. The major light element in the core at this stage will be sulfur. The internal pressure and temperature increased with the growth of the planets, and the metal component depleted in S was molten. The metallic melt contained both Si and O at high pressure in the deep magma ocean in the later stage. Thus, the core contains S, Si, and O in this stage of core formation. Partitioning experiments between solid and liquid metals indicate that S is partitioned into the liquid metal, whereas O is weakly into the liquid. Partitioning of Si changes with the metallic iron phases, i.e., fcc iron-alloy coexisting with the metallic liquid below 30 GPa is depleted in Si. Whereas hcp-Fe alloy above 30 GPa coexisting with the liquid favors Si. This contrast of Si partitioning provides remarkable difference in compositions of the solid inner core and liquid outer core among different terrestrial planets. Our melting experiments of the Fe-S-Si and Fe-O-S systems at high pressure indicate the core-adiabats in small planets, Mercury and Mars, are greater than the slope of the solidus and liquidus curves of these systems. Thus, in these planets, the core crystallized at the top of the liquid core and 'snowing core' formation occurred during crystallization. The solid inner core is depleted in both Si and S whereas the liquid outer core is relatively enriched in Si and S in these planets. On the other hand, the core adiabats in large planets, Earth and Venus, are smaller than the solidus and liquidus curves of the systems. The inner core of these planets crystallized at the center of the core and it has the relatively Si rich inner core and the S enriched outer core. Based on melting and solid-liquid partitioning, the equation of state, and sound velocity of iron-light element alloys, we examined the plausible distribution of light elements in the liquid outer and solid inner cores of the terrestrial planets.

Pioneers 10 and 11 deep space missions

NASA Technical Reports Server (NTRS)

Dyal, Palmer

1990-01-01

Pioneers 10 and 11 were launched from Earth, 2 March 1972, and 5 April 1973, respectively. The Pioneers were the first spacecraft to explore the asteroid belt and the first to encounter the giant planets, Jupiter and Saturn. The Pioneer 10 spacecraft is now the most distant man-made object in our solar system and is farther from the Sun than all nine planets. It is 47 AU from the Sun and is moving in a direction opposite to that of the Sun's motion through the galaxy. Pioneer 11 is 28 AU from the Sun and is traveling in the direction opposite of Pioneer 10, in the same direction as the Sun moves in the galaxy. These two Pioneer spacecraft provided the first large-scale, in-situ measurements of the gas and dust surrounding a star, the Sun. Since launch, the Pioneers have measured large-scale properties of the heliosphere during more than one complete 11-year solar sunspot cycle, and have measured the properties of the expanding solar atmosphere, the transport of cosmic rays into the heliosphere, and the high-energy trapped radiation belts and magnetic fields associated with the planets Jupiter and Saturn. Accurate Doppler tracking of these spin-stabilized spacecraft was used to search for differential gravitational forces from a possible trans-Neptunian planet and to search for gravitational radiation. Future objectives of the Pioneer 10 and 11 missions are to continue measuring the large-scale properties of the heliosphere and to search for its boundary with interstellar space.

KSC-05pd2273

NASA Image and Video Library

2005-09-29

KENNEDY SPACE CENTER, FLA. - On the Shuttle Landing Facility at NASA Kennedy Space Center, the Atlas V fairing halves for the New Horizons spacecraft have been offloaded from the Russian cargo plane (background). The fairing halves will be transported to Astrotech Space Operations in Titusville. The fairing later will be placed around the New Horizons spacecraft in the Payload Hazardous Service Facility. A fairing protects a spacecraft during launch and flight through the atmosphere. Once in space, it is jettisoned. The Lockheed Martin Atlas V is the launch vehicle for the New Horizons spacecraft, which is designed to make the first reconnaissance of Pluto and Charon - a "double planet" and the last planet in our solar system to be visited by spacecraft. The mission will then visit one or more objects in the Kuiper Belt region beyond Neptune. New Horizons is scheduled to launch in January 2006, swing past Jupiter for a gravity boost and scientific studies in February or March 2007, and reach Pluto and its moon, Charon, in July 2015.

KSC-05pd2274

NASA Image and Video Library

2005-09-29

KENNEDY SPACE CENTER, FLA. - On the Shuttle Landing Facility at NASA Kennedy Space Center, one of the Atlas V fairing halves for the New Horizons spacecraft is offloaded from the Russian cargo plane. The fairing halves will be transported to Astrotech Space Operations in Titusville. The fairing later will be placed around the New Horizons spacecraft in the Payload Hazardous Service Facility. A fairing protects a spacecraft during launch and flight through the atmosphere. Once in space, it is jettisoned. The Lockheed Martin Atlas V is the launch vehicle for the New Horizons spacecraft, which is designed to make the first reconnaissance of Pluto and Charon - a "double planet" and the last planet in our solar system to be visited by spacecraft. The mission will then visit one or more objects in the Kuiper Belt region beyond Neptune. New Horizons is scheduled to launch in January 2006, swing past Jupiter for a gravity boost and scientific studies in February or March 2007, and reach Pluto and its moon, Charon, in July 2015.

KSC-05pd2271

NASA Image and Video Library

2005-09-29

KENNEDY SPACE CENTER, FLA. - A Russian cargo plane sits on the Shuttle Landing Facility at NASA Kennedy Space Center with the Atlas V fairing for the New Horizons spacecraft inside. The two fairing halves will be removed, loaded onto trucks and transported to Astrotech Space Operations in Titusville. The fairing later will be placed around the New Horizons spacecraft in the Payload Hazardous Service Facility. A fairing protects a spacecraft during launch and flight through the atmosphere. Once in space, it is jettisoned. The Lockheed Martin Atlas V is the launch vehicle for the New Horizons spacecraft, which is designed to make the first reconnaissance of Pluto and Charon - a "double planet" and the last planet in our solar system to be visited by spacecraft. The mission will then visit one or more objects in the Kuiper Belt region beyond Neptune. New Horizons is scheduled to launch in January 2006, swing past Jupiter for a gravity boost and scientific studies in February or March 2007, and reach Pluto and its moon, Charon, in July 2015.

MESSENGER: The Discovery Mission to Mercury

NASA Astrophysics Data System (ADS)

McNutt, R. L.; Solomon, S. C.; Gold, R. E.; Domingue, D. L.

2004-12-01

NASA's MErcury, Surface, Space ENvironment, GEochenistry, and Ranging (MESSENGER) spacecraft, launched on 3 August 2004, has begun its voyage to initiate a new era in our understanding of the terrestrial planets. The mission, spacecraft, and payload are designed to answer six fundamental questions regarding the innermost planet: What planetary formational processes led to Mercury's high metal/silicate ratio? What is the geological history of Mercury? What are the nature and origin of Mercury's magnetic field? What are the structure and state of Mercury's core? What are the radar-reflective materials at Mercury's poles? What are the important volatile species and their sources and sinks on and near Mercury? Planet formational hypotheses will be tested by measuring the surface abundances of major elements by X-ray and gamma-ray spectrometry. The geological history will be determined from high-resolution color imaging of the heavily cratered highlands, intercrater plains, and smooth plains. MESSENGER will provide detailed views of both the Caloris basin and its antipodal terrain. Topographic, mineralogical, and elemental abundance data will be used to seek evidence of volcanic features and units. Measurement of Mercury's magnetic field and its interaction with the solar wind will distinguish the intrinsic dipole and quadrupole components while separating these from the current systems driven by solar-wind-induced convection. The structure of the internal field will put constraints on dynamo models. Such models will also be constrained by measuring Mercury's libration to determine the extent of a fluid outer core. Both water ice and sulfur have been postulated as major constituents of the high-radar-backscatter polar deposits. MESSENGER will combine gamma-ray and neutron spectrometry of the surface with ultraviolet spectrometry and in situ particle measurements to detect both neutral and charged species originating from the surface. Such measurements will address the sources and sinks of volatiles and their couplings with the surface on a global basis as well as the nature of the polar deposits. To broaden scientific participation in the mission, the MESSENGER project is working with NASA to establish a Participating Scientist Program. The MESSENGER team is also continuing its informal interaction with members of the BepiColombo project to maximize the overall scientific return from both missions.

A geological basis for the exploration of the planets: Introduction

NASA Technical Reports Server (NTRS)

Greeley, R.; Carr, M. H.

1976-01-01

The geological aspects of solar-system exploration were considered by first showing how geologic data are related to space science in general, and, second, by discussing the approach used in planetary geology. The origin, evolution, and distribution of matter condensed in the form of planets, satellites, comets, and asteroids were studied. Terrestrial planets, comets, and asteroids, and the solid satellites of the outer planets are discussed. Jupiter and Saturn, in particular, have satellites of prime importance. Geophysics, geochemistry, geodesy, cartography, and other disciplines concerned with the solid planets were all included.

Mercury: a final prediction for internal thermal and physical structure, prior to MESSENGER data

NASA Astrophysics Data System (ADS)

Prentice, A. J.

2008-05-01

The confirmation by the NASA MESSENGER spacecraft that Mercury has an internal magnetic field that is well described by a dipole nearly aligned with the spin axis strongly suggests that the planet may have an outer core of molten metal (S. Solomon, MESSENGER news release of 30 January 2008). The existence of an internal layer of liquid has also been invoked to explain radar measurements of the large amplitude of the longitudinal libration of Mercury relative to the value expected for a wholly solid planet (J.L. Margot et al 2007 Science 316 710). The existence of molten metal in the planet`s interior is surprising since previous numerical models for the thermal evolution of the planet, calculated on the basis of the heat released by the decay of the radioactive isotopes of U and Th, indicated that the present temperature at the edge of the metal core is only ~ 1200 K (cf. Siegfried & Solomon 1974 Icarus 23 192) . This value is well below the melting temperature Tm = 2030 K of Fe-Ni alloy at the core/mantle boundary (CMB) pressure of ~ 70 kbar. Those earlier thermal calculations were, however, based on low abundances of U and Th found in lunar samples. Prentice (2008 LPSC 2008 abs. # 1945.pdf - see URL below) has put forward a new model for the bulk chemical composition of Mercury. It is based on the idea that this planet condensed from a gas ring that was cast off by the protosolar cloud close to the planet`s present orbit. The temperature of the gas ring Tn at the moment of detachment from the cloud is 1628 K and the pressure on the mean orbit of the ring is 0.168 bar. Because Tn is so high, the condensate contains a much reduced proportion of magnesium silicates relative to metals. This is because metals have a much lower vapour pressure than those silicates. The condensate consists mostly of Fe-Ni-Cr-Co-V (mass fraction 0.671), gehlenite (0.190) and Mg-silicates (0.081). What is really important in the gas ring model of solar system origin, however, is that the abundances of U and Th in the Mercury condensate are a factor of 4.3 times those of the Earth. The UO2 mass fraction is 6.4 × 10- 8. All bulk compositional mass fractions are computed using the protosolar elemental abundance compilation of K. Lodders (2003 Ap.J. 591 1220). The cold-start thermal evolutionary model for Mercury presented in Prentice (2008) is based on the U & Th abundances given above. The temperature at the CMB rises quickly from 350 K to 1630 K in 1 byr. Further increase was then stopped since it was assumed that efficient solid state convection set in once the temperature exceeds the value 0.7 Tm, where Tm is the local melt temperature of the rock. But a creep factor Fcreep = 0.6 - 0.7 is true just for metals, not rocks. For silicates, a higher factor ~ 1 is indicated (J-P Poirier 1985 Creep of Crystals, CUP, p. 163). Adopting Fcreep = 0.9, the CMB temperature now rises to 2100 K and the outer portion of the core become molten. If a hot-start is made, corresponding to an initial fully- differentiated body with central temperature Tc = 2500 K, the present Tc is 2150 K and the outer 13.2% of the core`s mass remains molten at solar age. This layer is still cooling at its inner edge. The estimated axial moment-of-inertia factor of this new hot model for Mercury is C/MR2 = 0.330 +/- 0.003. I thank George W. Null [JPL] for much hospitality in Pasadena and Steve Morton [Monash] for technical support.

KSC-2009-1014

NASA Image and Video Library

2009-01-06

CAPE CANAVERAL, Fla. -- The shipping container holding the Kepler spacecraft is lifted off the trailer outside Astrotech in Titusville, Fla. A NASA Discovery mission, Kepler is specifically designed to survey our region of the Milky Way galaxy to discover hundreds of Earth-size and smaller planets in or near the habitable zone and determine how many of the billions of stars in our galaxy have such planets. Results from this mission will allow us to place our solar system within the continuum of planetary systems in the Galaxy. The spacecraft will be processed at Astrotech before being carried to its launch pad at Cape Canaveral. .NASA's planet-hunting Kepler mission is scheduled to launch no earlier than March 5, 2009, atop a Delta II rocket. Photo credit: NASA/Kim Shiflett

Estimation and assessment of Mars contamination.

PubMed

Debus, A

2005-01-01

Since the beginning of the exploration of Mars, more than fourty years ago, thirty-six missions have been launched, including fifty-nine different space systems such as fly-by spacecraft, orbiters, cruise modules, landing or penetrating systems. Taking into account failures at launch, about three missions out of four have been successfully sent toward the Red Planet. The fact today is that Mars orbital environment includes orbiters and perhaps debris, and that its atmosphere and its surface include terrestrial compounds and dormant microorganisms. Coming from the UN Outer Space Treaty [United Nations Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies (the "Outer Space Treaty") referenced 610 UNTS 205 - resolution 2222(XXI) of December 1966] and according to the COSPAR planetary protection policy recommendations [COSPAR Planetary Protection Policy (20 October 2002), accepted by the Council and Bureau, as moved for adoption by SC F and PPP, prepared by the COSPAR/IAU Workshop on Planetary Protection, 4/02 with updates 10/0, 2002], Mars environment has to be preserved so as not to jeopardize the scientific investigations, and the level of terrestrial material brought on and around Mars theoretically has to comply with this policy. It is useful to evaluate what and how many materials, compounds and microorganisms are on Mars, to list what is in orbit and to identify where all these items are. Considering assumptions about materials, spores and gas location and dispersion on Mars, average contamination levels can be estimated. It is clear now that as long as missions are sent to other extraterrestrial bodies, it is not possible to keep them perfectly clean. Mars is one of the most concerned body, and the large number of missions achieved, on-going and planned now raise the question about its possible contamination, not necessarily from a biological point of view, but with respect to all types of contamination. Answering this question, will help to assess the potential effects of such contamination on scientific results and will address concerns relative to any ethical considerations about the contamination of other planets. c2005 COSPAR. Published by Elsevier Ltd. All rights reserved.

Technologies for Outer Planet Missions: A companion to the OPAG Exploration Strategy

NASA Astrophysics Data System (ADS)

Beauchamp, Patricia; McKinnon, William

The Outer Planets Assessment Group (OPAG) advocates the need for a focused technology program for the next Outer Planet Flagship Mission after the Europa Jupiter System Mission (EJSM) in order to be ready for a launch in the mid-2020s. Current planning assumes that a mission to Titan and Enceladus will be the highest priority. The challenges common to all Outer Planetary (OP) missions—large distances, long ight times, and stringent limitations on mass, power, and data rate—mean that all missions can signicantly benet from technical advances in a number of broad areas. Since technology development timescales are long, it is most productive to base technology requirements on the expected general characteristics of future missions. While the strategic Flagship mission concepts are better understood, an estimate of the needs for the competed small class (Discovery) and medium class (New Frontiers) missions can be included in constructing an effective technology investment plan. Technology investment priorities are guided by the requirements established in mission and system studies that are focused on the highest priority science objectives. The next OP mission (after EJSM) may involve orbiting one or both of the saturnian satellites Titan and Enceladus. Other potential OP missions include atmospheric probes of the giant planets, in situ exploration at Titan, flybys or orbiters to the ice giants Neptune and Uranus, and ultimately, landing on Europa or Enceladus. The breadth of technology needed for OP exploration clearly calls for an aggressive and focused technology development strategy that aligns with the Decadal Survey recommended mission profile, and includes technologies developed by NASA, as well as acquisition of applicable technologies from other government and commercial sectors. This presentation shows how the technologies discussed in the white paper derive from the Outer Planet science goals, with particular attention to those required by a mission to Titan and Enceladus -active solar system satellites. We explain why they are significant relative to current solar system goals/priorities and outline how they should influence the next generation of solar system exploration missions. Government sponsorship acknowledged

Technologies for Outer Planet Missions: A Companion to the OPAG Exploration Strategy

NASA Astrophysics Data System (ADS)

Beauchamp, P. M.; McKinnon, W. B.

2009-12-01

The Outer Planets Assessment Group (OPAG) advocates the need for a focused technology program for the next Outer Planet Flagship Mission after the Europa Jupiter System Mission (EJSM) in order to be ready for a launch in the mid-2020s. Current planning assumes that a mission to Titan and Enceladus will be the highest priority. The challenges common to all Outer Planetary (OP) missions — large distances, long flight times, and stringent limitations on mass, power, and data rate — mean that all missions can significantly benefit from technical advances in a number of broad areas. Since technology development timescales are long, it is most productive to base technology requirements on the expected general characteristics of future missions. While the strategic Flagship mission concepts are better understood, an estimate of the needs for the competed small class (Discovery) and medium class (New Frontiers) missions can be included in constructing an effective technology investment plan. Technology investment priorities are guided by the requirements established in mission and system studies that are focused on the highest priority science objectives. The next OP mission (after EJSM) may involve orbiting one or both of the saturnian satellites Titan and Enceladus. Other potential OP missions include atmospheric probes of the giant planets, in situ exploration at Titan, flybys or orbiters to the ice giants Neptune and Uranus, and ultimately, landing on Europa or Enceladus. The breadth of technology needed for OP exploration clearly calls for an aggressive and focused technology development strategy that aligns with the Decadal Survey recommended mission profile, and includes technologies developed by NASA, as well as acquisition of applicable technologies from other government and commercial sectors. This presentation shows how the technologies discussed in the white paper derive from the Outer Planet science goals, with particular attention to those required by a mission to Titan and Enceladus. We explain why they are significant relative to current solar system goals/priorities and outline how they should influence the next generation of solar system exploration missions.

Technologies for Outer Planet Missions: A companion to the OPAG Exploration Strategy

NASA Astrophysics Data System (ADS)

Beauchamp, Patricia; McKinnon, William

2010-05-01

The Outer Planets Assessment Group (OPAG) advocates the need for a focused technology program for the next Outer Planet Flagship Mission after the Europa Jupiter System Mission (EJSM) in order to be ready for a launch in the mid-2020s. Current planning assumes that a mission to Titan and Enceladus will be the highest priority. The challenges common to all Outer Planetary (OP) missions—large distances, long flight times, and stringent limitations on mass, power, and data rate—mean that all missions can significantly benefit from technical advances in a number of broad areas. Since technology development timescales are long, it is most productive to base technology requirements on the expected general characteristics of future missions. While the strate¬gic Flagship mission concepts are better understood, an estimate of the needs for the competed small class (Discovery) and medium class (New Frontiers) missions can be included in constructing an effective technology investment plan. Technology investment priorities are guided by the requirements established in mission and system studies that are focused on the highest priority science objectives. The next OP mission (after EJSM) may involve orbiting one or both of the saturnian satellites Titan and Enceladus. Other potential OP missions include atmospheric probes of the giant planets, in situ exploration at Titan, flybys or orbiters to the ice giants Neptune and Uranus, and ultimately, landing on Europa or Enceladus. The breadth of technology needed for OP exploration clearly calls for an aggressive and focused technology development strategy that aligns with the Decadal Survey recommended mission profile, and includes technologies developed by NASA, as well as acquisition of applicable technologies from other government and commercial sectors. This presentation shows how the technologies discussed in the white paper derive from the Outer Planet science goals, with particular attention to those required by a mission to Titan and Enceladus. We explain why they are significant relative to current solar system goals/priorities and outline how they should influence the next generation of solar system exploration missions. Government sponsorship acknowledged

Electric Sail Propulsion for Exploring Nearby Interstellar Space

NASA Technical Reports Server (NTRS)

Johnson, Les; Wiegmann, Bruce; Bangham, Mike

2015-01-01

An Electric Sail is a revolutionary propellant-less propulsion system that is ideal for deep space missions to the outer planets, the Heliopause, and beyond. It is revolutionary in that it uses momentum exchange with the hypersonic solar wind to propel a spacecraft within the heliosphere. The momentum exchange is affected by the deflection of charged solar wind particles by an array of electrically biased wires that extend outward up to 30 km from a slowly rotating spacecraft. A high-voltage, positive bias on the wires, which are oriented normal to the solar wind flow, deflects the streaming protons, resulting in a reaction force on the wires that is also directed radially away from the sun. Over a period of months, this small force can accelerate the spacecraft to enormous speeds-on the order of 100-150 km/s (approximately 20 to 30 AU/yr). Unlike solar sails, Electric Sails do not rely on a fixed area to produce thrust. In fact, as they move away from the Sun and solar wind pressure decreases, the area for solar proton momentum transfer becomes larger, increasing system efficiency. As a result, thrust decreases at ˜1/r**(7/6) instead of the ˜1/r**2 rate typical for solar sails. The net effect is that an increased radial range of operation, together with increased thrust, both contribute to higher velocities and shorter total trip times to distant destinations. The MSFC Advanced Concepts Office (ACO) was awarded a Phase II NASA Innovative Advanced Concepts (NIAC) study to mature the technology for possible future demonstration and implementation. Preliminary results indicate that the physics of the system is viable and that a spacecraft propelled by an Electric Sail could reach the Heliopause in less than 15 years - and could be developed within a decade.

Four Fallacies and an Oversight: Searching for Martian Life

NASA Astrophysics Data System (ADS)

Rummel, J. D.; Conley, C. A.

2017-10-01

While it is anticipated that future human missions to Mars will increase the amount of biological and organic contamination that might be distributed on that planet, robotic missions continue to grow in capability and complexity, requiring precautions to be taken now to protect Mars, and particularly areas of Mars that might be Special Regions. Such precautionary cleanliness requirements for spacecraft have evolved over the course of the space age, as we have learned more about planetary environments, and are the subject of regular deliberations and decisions sponsored by the Committee on Space Research (COSPAR). COSPAR's planetary protection policy is maintained as an international consensus standard for spacecraft cleanliness that is recognized by the United Nations Committee on the Peaceful Uses of Outer Space. In response to the paper presented in this issue by Fairén et al. (2017), we examine both their concept of evidence for possible life on Mars and their logic in recommending that spacecraft cleanliness requirements be relaxed to access Special Regions "before it is too late." We find that there are shortcomings in their plans to look for evidence of life on Mars, that they do not support their contention that appropriate levels of spacecraft cleanliness are unaffordable, that there are major risks in assuming martian life could be identified by nucleic acid sequence comparison (especially if those sequences are obtained from a Special Region contaminated with Earth life), and that the authors do not justify their contention that exploration with dirty robots, now, is preferable to the possibility that later contamination will be spread by human exploration. We also note that the potential effects of contaminating resources and environments essential to future human occupants of Mars are both significant and not addressed by Fairén et al. (2017).

A Terminator View from Mercury Flyby 2

NASA Image and Video Library

2009-04-21

This high-resolution NAC image shows a view of Mercury dawn terminator, the division between the sunlit dayside and dark nightside of the planet, as seen as the MESSENGER spacecraft departed the planet during the mission second Mercury flyby.

Cassini's grand finale

NASA Astrophysics Data System (ADS)

Colwell, Joshua

2017-09-01

Flying closer to Saturn than ever before, the Cassini spacecraft has spent the last few months diving between the planet and its rings, collecting new and unique data ahead of its suicidal plunge into the planet on 15 September, as Joshua Colwell reveals

The Pioneer Missions

NASA Technical Reports Server (NTRS)

Lasher, Larry E.; Hogan, Robert (Technical Monitor)

1999-01-01

This article describes the major achievements of the Pioneer Missions and gives information about mission objectives, spacecraft, and launches of the Pioneers. Pioneer was the United States' longest running space program. The Pioneer Missions began forty years ago. Pioneer 1 was launched shortly after Sputnik startled the world in 1957 as Earth's first artificial satellite at the start of the space age. The Pioneer Missions can be broken down into four distinct groups: Pioneer (PN's) 1 through 5, which comprise the first group - the "First Pioneers" - were launched from 1958 through 1960. These Pioneers made the first thrusts into space toward the Moon and into interplanetary orbit. The next group - the "Interplanetary Pioneers" - consists of PN's 6 through 9, with the initial launch being in 1965 (through 1968); this group explored inward and outward from Earth's orbit and travel in a heliocentric orbit around the Sun just as the Earth. The Pioneer group consisting of 10 and 11 - the "Outer Solar System Pioneers" - blazed a trail through the asteroid belt and was the first to explore Jupiter, Saturn and the outer Solar System and is seeking the borders of the heliosphere and will ultimately journey to the distant stars. The final group of Pioneer 12 and 13 the "Planetary Pioneers" - traveled to Earth's mysterious twin, Venus, to study this planet.

Dawn Blue Glow Artist Concept

NASA Image and Video Library

2015-03-02

This artist concept shows NASA Dawn spacecraft arriving at the dwarf planet Ceres. Dawn travels through space using a technology called ion propulsion, with ions glowing with blue light are accelerated out of an engine, giving the spacecraft thrust.

Color Between Moons

NASA Image and Video Library

2010-02-05

Two of Saturn moons straddle the planet rings in this color view from NASA Cassini spacecraft. Mimas is closest to NASA Cassini spacecraft here. Epimetheus is on the far side of the rings. Saturn shadow cuts across the middle of the rings.

The accretion of migrating giant planets

NASA Astrophysics Data System (ADS)

Dürmann, Christoph; Kley, Wilhelm

2017-02-01

Aims: Most studies concerning the growth and evolution of massive planets focus either on their accretion or their migration only. In this work we study both processes concurrently to investigate how they might mutually affect one another. Methods: We modeled a two-dimensional disk with a steady accretion flow onto the central star and embedded a Jupiter mass planet at 5.2 au. The disk is locally isothermal and viscosity is modeled using a constant α. The planet is held on a fixed orbit for a few hundred orbits to allow the disk to adapt and carve a gap. After this period, the planet is released and free to move according to the gravitational interaction with the gas disk. The mass accretion onto the planet is modeled by removing a fraction of gas from the inner Hill sphere, and the removed mass and momentum can be added to the planet. Results: Our results show that a fast migrating planet is able to accrete more gas than a slower migrating planet. Utilizing a tracer fluid we analyzed the origin of the accreted gas originating predominantly from the inner disk for a fast migrating planet. In the case of slower migration, the fraction of gas from the outer disk increases. We also found that even for very high accretion rates, in some cases gas crosses the planetary gap from the inner to the outer disk. Our simulations show that the crossing of gas changes during the migration process as the migration rate slows down. Therefore, classical type II migration where the planet migrates with the viscous drift rate and no gas crosses the gap is no general process but may only occur for special parameters and at a certain time during the orbital evolution of the planet.

Juno Post-arrival View

NASA Image and Video Library

2016-07-12

This color view from NASA's Juno spacecraft is made from some of the first images taken by JunoCam after the spacecraft entered orbit around Jupiter on July 5th (UTC). The view shows that JunoCam survived its first pass through Jupiter's extreme radiation environment, and is ready to collect images of the giant planet as Juno begins its mission. The image was taken on July 10, 2016 at 5:30 UTC, when the spacecraft was 2.7 million miles (4.3 million kilometers) from Jupiter on the outbound leg of its initial 53.5-day capture orbit. The image shows atmospheric features on Jupiter, including the Great Red Spot, and three of Jupiter's four largest moons. JunoCam will continue to image Jupiter during Juno's capture orbits. The first high-resolution images of the planet will be taken on August 27 when the Juno spacecraft makes its next close pass to Jupiter. http://photojournal.jpl.nasa.gov/catalog/PIA20707

Contamination of planets by nonsterile flight hardware.

NASA Technical Reports Server (NTRS)

Wolfson, R. P.; Craven, C. W.

1971-01-01

The various factors about space missions and spacecraft involved in the study of nonsterile space flight hardware with respect to their effects on planetary quarantine are reviewed. It is shown that methodology currently exists to evaluate the various potential contamination sources and to take appropriate steps in the design of spacecraft ha rdware and mission parameters so that quarantine constraints are met. This work should be done for each program so that the latest knowledge pertaining to various biological questions is utilized, and so that the specific hardware designs of the program can be assessed. The general trend of specific recommendations include: (1) biasing the launch trajectory away from planet to assure against accidental impact of the spacecraft; (2) selecting planetary orbits that meet quarantine requirements - both for accidental impact and for minimizing contamination probabilities due to ejecta; and (3) manufacturing and handling spacecraft under cleanliness conditions assuring minimum bioload.

InSight Spacecraft Lift to Spin Table & Pre-Spin Processing

NASA Image and Video Library

2018-03-28

In the Astrotech facility at Vandenberg Air Force Base in California, technicians and engineers inspect NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, or InSight, spacecraft after it was placed on a spin table during preflight processing. InSight will be the first mission to look deep beneath the Martian surface. It will study the planet's interior by measuring its heat output and listen for marsquakes. The spacecraft will use the seismic waves generated by marsquakes to develop a map of the planet’s deep interior. The resulting insight into Mars’ formation will provide a better understanding of how other rocky planets, including Earth, were created. InSight is scheduled for liftoff May 5, 2018.

Skirting Saturn's Rings and Skimming Its Cloud Tops: Planning Cassini's End of Mission

NASA Technical Reports Server (NTRS)

Manor-Chapman, Emily; Magee, Kari; Brooks, Shawn; Edgington, Scott; Heventhal, William; Sturm, Erick

2014-01-01

In October 2010, the Cassini spacecraft embarked on the seven-year Solstice Mission. The mission will culminate with a spectacular series of orbits that bring Cassini between Saturn's innermost ring, the D ring, and the cloud tops of the planet. The spacecraft will make its closest passages ever to the planet allowing for unprecedented science to be collected on Saturn and its rings. These final orbits will expose the spacecraft to new environments, which presents a number of challenges to planning the final mission phase. While these challenges will require adaptations to planning processes and operations, they are not insurmountable. This paper describes the challenges identified and the steps taken to mitigate them to enable collection of unique Saturn system science.

Europa and Callisto under the watchful gaze of Jupiter

NASA Technical Reports Server (NTRS)

2000-01-01

One moment in an ancient, orbital dance is caught in this color picture taken by NASA's Cassini spacecraft on Dec. 7, 2000, just as two of Jupiter's four major moons, Europa and Callisto, were nearly perfectly aligned with each other and the center of the planet.

The distances are deceiving. Europa, seen against Jupiter, is 600,000 kilometers (370,000 miles) above the planet's cloud tops. Callisto, at lower left, is nearly three times that distance from the cloud tops. Europa is a bit smaller than Earth's Moon and has one of the brightest surfaces in the solar system. Callisto is 50 percent bigger -- roughly the size of Saturn's largest satellite, Titan -- and three times darker than Europa. Its brightness had to be enhanced in this picture, relative Europa's and Jupiter's, in order for Callisto to be seen in this image.

Europa and Callisto have had very different geologic histories but share some surprising similarities, such as surfaces rich in ice. Callisto has apparently not undergone major internal compositional stratification, but Europa's interior has differentiated into a rocky core and an outer layer of nearly pure ice. Callisto's ancient surface is completely covered by large impact craters: The brightest features seen on Callisto in this image were discovered by the Voyager spacecraft in 1979 to be bright craters, like those on our Moon. In contrast, Europa's young surface is covered by a wild tapestry of ridges, chaotic terrain and only a handful of large craters.

Recent data from the magnetometer carried by the Galileo spacecraft, which has been in orbit around Jupiter since 1995, indicate the presence of conducting fluid, most likely salty water, inside both worlds.

Scientists are eager to discover whether the surface of Saturn's Titan resembles that of Callisto or Europa, or whether it is entirely different when Cassini finally reaches its destination in 2004.

Cassini is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Office of Space Science, Washington, D.C.

Hybrid rocket propulsion systems for outer planet exploration missions

NASA Astrophysics Data System (ADS)

Jens, Elizabeth T.; Cantwell, Brian J.; Hubbard, G. Scott

2016-11-01

Outer planet exploration missions require significant propulsive capability, particularly to achieve orbit insertion. Missions to explore the moons of outer planets place even more demanding requirements on propulsion systems, since they involve multiple large ΔV maneuvers. Hybrid rockets present a favorable alternative to conventional propulsion systems for many of these missions. They typically enjoy higher specific impulse than solids, can be throttled, stopped/restarted, and have more flexibility in their packaging configuration. Hybrids are more compact and easier to throttle than liquids and have similar performance levels. In order to investigate the suitability of these propulsion systems for exploration missions, this paper presents novel hybrid motor designs for two interplanetary missions. Hybrid propulsion systems for missions to Europa and Uranus are presented and compared to conventional in-space propulsion systems. The hybrid motor design for each of these missions is optimized across a range of parameters, including propellant selection, O/F ratio, nozzle area ratio, and chamber pressure. Details of the design process are described in order to provide guidance for researchers wishing to evaluate hybrid rocket motor designs for other missions and applications.

Voyager Approaches Final Frontier Artist Concept

NASA Image and Video Library

2003-12-12

An artist's concept illustrates the positions of the Voyager spacecraft in relation to structures formed around our Sun by the solar wind. Also illustrated is the termination shock, a violent region the spacecraft must pass through before reaching the outer limits of the solar system. At the termination shock, the supersonic solar wind abruptly slows from an average speed of 400 kilometers per second to less than 100 kilometer per second (900,000 to less than 225,000 miles per hour). Beyond the termination shock is the solar system's final frontier, the heliosheath, a vast region where the turbulent and hot solar wind is compressed as it presses outward against the interstellar wind that is beyond the heliopause. A bow shock likely forms as the interstellar wind approaches and is deflected around the heliosphere, forcing it into a teardrop-shaped structure with a long, comet-like tail. The exact location of the termination shock is unknown, and it originally was thought to be closer to the Sun than Voyager 1 currently is. As Voyager 1 cruised ever farther from the Sun, it confirmed that all the planets are inside an immense bubble blown by the solar wind and the termination shock was much more distant. http://photojournal.jpl.nasa.gov/catalog/PIA04927

Results of using the global positioning system to maintain the time and frequency synchronization in the Deep Space Network

NASA Technical Reports Server (NTRS)

Clements, P. A.; Kirk, A.; Unglaub, R.

1987-01-01

There are two hydrogen maser clocks located at each signal processing center (SPC) in the DSN. Close coordination of the time and frequency of the SPC clocks is needed to navigate spacecraft to the outer planets. A recent example was the Voyager spacecraft's encounter with Uranus in January 1986. The clocks were adjusted with the goal of minimizing time and frequency offsets between the SPCs at encounter. How time and frequency at each SPC is estimated using data acquired from the Global Positioning System Timing Receivers operating on the NBS-BIH (National Bureau of Standards-Bureau International de l'Heure) tracking schedule is described. These data are combined with other available timing receiver data to calculate the time offset estimates. The adjustment of the clocks is described. It was determined that long range hydrogen maser drift is quite predictable and adjustable within limits. This enables one to minimize time and frequency differences between the three SPCs for many months by matching the drift rates of the three standards. Data acquisition and processing techniques using a Kalman filter to make estimates of time and frequency offsets between the clocks at the SPCs and UTC(NBS) (Coordinated Universal Time realized at NBS) are described.

Dust Ablation in Pluto's Atmosphere

NASA Astrophysics Data System (ADS)

Horanyi, M.; Poppe, A. R.; Sternovsky, Z.

2015-12-01

Based on measurements by in situ dust detectors onboard the Pioneer and New Horizon spacecraft the total production rate of dust particles born in the Kuiper belt can be estimated to be on the order of 5 x 10 ^3 kg/s in the approximate size range of 1 - 10 micron. These particles slowly migrate inward due to Poynting - Robertson drag and their spatial distribution is shaped by mean motion resonances with the gas giant planets in the outer solar system. The expected mass influx into Pluto's atmosphere is on the order of 50 kg/day, and the arrival speed of the incoming particles is on the order of 3 - 4 km/s. We have followed the ablation history as function of speed and size of dust particles in Pluto's atmosphere, and found that, if the particles are rich in volatiles, they can fully sublimate due to drag heating and deposit their mass in a narrow layer. This deposition might promote the formation of the haze layers observed by the New Horizons spacecraft. This talk will explore the constraints on the composition of the dust particles, as well as on our newly developed models of Pluto's atmosphere that can be learned by matching the altitude where haze layers could be formed.

Small Body Exploration Technologies as Precursors for Interstellar Robotics

NASA Astrophysics Data System (ADS)

Noble, R. J.; Sykes, M. V.

The scientific activities undertaken to explore our Solar System will be very similar to those required someday at other stars. The systematic exploration of primitive small bodies throughout our Solar System requires new technologies for autonomous robotic spacecraft. These diverse celestial bodies contain clues to the early stages of the Solar System's evolution, as well as information about the origin and transport of water-rich and organic material, the essential building blocks for life. They will be among the first objects studied at distant star systems. The technologies developed to address small body and outer planet exploration will form much of the technical basis for designing interstellar robotic explorers. The Small Bodies Assessment Group, which reports to NASA, initiated a Technology Forum in 2011 that brought together scientists and technologists to discuss the needs and opportunities for small body robotic exploration in the Solar System. Presentations and discussions occurred in the areas of mission and spacecraft design, electric power, propulsion, avionics, communications, autonomous navigation, remote sensing and surface instruments, sampling, intelligent event recognition, and command and sequencing software. In this paper, the major technology themes from the Technology Forum are reviewed, and suggestions are made for developments that will have the largest impact on realizing autonomous robotic vehicles capable of exploring other star systems.

Small Body Exploration Technologies as Precursors for Interstellar Robotics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noble, Robert; /SLAC; Sykes, Mark V.

The scientific activities undertaken to explore our Solar System will be the same as required someday at other stars. The systematic exploration of primitive small bodies throughout our Solar System requires new technologies for autonomous robotic spacecraft. These diverse celestial bodies contain clues to the early stages of the Solar System's evolution as well as information about the origin and transport of water-rich and organic material, the essential building blocks for life. They will be among the first objects studied at distant star systems. The technologies developed to address small body and outer planet exploration will form much of themore » technical basis for designing interstellar robotic explorers. The Small Bodies Assessment Group, which reports to NASA, initiated a Technology Forum in 2011 that brought together scientists and technologists to discuss the needs and opportunities for small body robotic exploration in the Solar System. Presentations and discussions occurred in the areas of mission and spacecraft design, electric power, propulsion, avionics, communications, autonomous navigation, remote sensing and surface instruments, sampling, intelligent event recognition, and command and sequencing software. In this paper, the major technology themes from the Technology Forum are reviewed, and suggestions are made for developments that will have the largest impact on realizing autonomous robotic vehicles capable of exploring other star systems.« less

CHARACTERIZATION OF THE K2-19 MULTIPLE-TRANSITING PLANETARY SYSTEM VIA HIGH-DISPERSION SPECTROSCOPY, AO IMAGING, AND TRANSIT TIMING VARIATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Narita, Norio; Hori, Yasunori; Kusakabe, Nobuhiko

2015-12-10

K2-19 (EPIC201505350) is an interesting planetary system in which two transiting planets with radii ∼7 R{sub ⊕} (inner planet b) and ∼4 R{sub ⊕} (outer planet c) have orbits that are nearly in a 3:2 mean-motion resonance. Here, we present results of ground-based follow-up observations for the K2-19 planetary system. We have performed high-dispersion spectroscopy and high-contrast adaptive-optics imaging of the host star with the HDS and HiCIAO on the Subaru 8.2 m telescope. We find that the host star is a relatively old (≥8 Gyr) late G-type star (T{sub eff} ∼ 5350 K, M{sub s} ∼ 0.9 M{sub ⊙}, and R{sub s} ∼ 0.9 R{submore » ⊙}). We do not find any contaminating faint objects near the host star that could be responsible for (or dilute) the transit signals. We have also conducted transit follow-up photometry for the inner planet with KeplerCam on the FLWO 1.2 m telescope, TRAPPISTCAM on the TRAPPIST 0.6 m telescope, and MuSCAT on the OAO 1.88 m telescope. We confirm the presence of transit timing variations (TTVs), as previously reported by Armstrong and coworkers. We model the observed TTVs of the inner planet using the synodic chopping formulae given by Deck and Agol. We find two statistically indistinguishable solutions for which the period ratios (P{sub c}/P{sub b}) are located slightly above and below the exact 3:2 commensurability. Despite the degeneracy, we derive the orbital period of the inner planet P{sub b} ∼ 7.921 days and the mass of the outer planet M{sub c} ∼ 20 M{sub ⊕}. Additional transit photometry (especially for the outer planet) as well as precise radial-velocity measurements would be helpful to break the degeneracy and to determine the mass of the inner planet.« less

InSight Spacecraft Uncrating, Removal from Container, Lift Heat

NASA Image and Video Library

2018-03-01

Inside the Astrotech processing facility at Vandenberg Air Force Base in California, the heatshield for NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, or InSight, spacecraft is removed from protective wrapping. InSight was developed and built by Lockheed-Martin Space Systems in Denver, Colorado, and is scheduled for liftoff is May 5, 2018. InSight is the first mission to land on Mars and explore the Red Planet's deep interior. It will investigate processes that shaped the rocky planets of the inner solar system including Earth.

InSight Spacecraft Uncrating, Removal from Container, Lift Heat

NASA Image and Video Library

2018-03-01

Inside the Astrotech processing facility at Vandenberg Air Force Base in California, technicians and engineers inspect the heatshield for NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, or InSight, spacecraft. InSight was developed and built by Lockheed-Martin Space Systems in Denver, Colorado, and is scheduled for liftoff is May 5, 2018. InSight is the first mission to land on Mars and explore the Red Planet's deep interior. It will investigate processes that shaped the rocky planets of the inner solar system including Earth.

InSight Spacecraft Uncrating, Removal from Container, Lift Heat

NASA Image and Video Library

2018-03-01

Inside the Astrotech processing facility at Vandenberg Air Force Base in California, the heatshield for NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, or InSight, spacecraft has been removed from protective wrapping. InSight was developed and built by Lockheed-Martin Space Systems in Denver, Colorado, and is scheduled for liftoff is May 5, 2018. InSight is the first mission to land on Mars and explore the Red Planet's deep interior. It will investigate processes that shaped the rocky planets of the inner solar system including Earth.

United theory of planet formation (i): Tandem regime

NASA Astrophysics Data System (ADS)

Ebisuzaki, Toshikazu; Imaeda, Yusuke

2017-07-01

The present paper is the first one of a series of papers that present the new united theory of planet formation, which includes magneto-rotational instability and porous aggregation of solid particles in an consistent way. We here describe the ;tandem; planet formation regime, in which a solar system like planetary systems are likely to be produced. We have obtained a steady-state, 1-D model of the accretion disk of a protostar taking into account the magneto-rotational instability (MRI) and and porous aggregation of solid particles. We find that the disk is divided into an outer turbulent region (OTR), a MRI suppressed region (MSR), and an inner turbulent region (ITR). The outer turbulent region is fully turbulent because of MRI. However, in the range, rout(= 8 - 60 AU) from the central star, MRI is suppressed around the midplane of the gas disk and a quiet area without turbulence appears, because the degree of ionization of gas becomes low enough. The disk becomes fully turbulent again in the range rin(= 0.2 - 1 AU), which is called the inner turbulent region, because the midplane temperature become high enough (>1000 K) due to gravitational energy release. Planetesimals are formed through gravitational instability at the outer and inner MRI fronts (the boundaries between the MRI suppressed region (MSR) and the outer and inner turbuent regions) without particle enhancement in the original nebula composition, because of the radial concentration of the solid particles. At the outer MRI front, icy particles grow through low-velocity collisions into porous aggregates with low densities (down to ∼10-5 gcm-3). They eventually undergo gravitational instability to form icy planetesimals. On the other hand, rocky particles accumulate at the inner MRI front, since their drift velocities turn outward due to the local maximum in gas pressure. They undergo gravitational instability in a sub-disk of pebbles to form rocky planetesimals at the inner MRI front. They are likely to be volatile-free because of the high temperature (>1000 K) at this formation site. Such water-free rocky particles may explain the formation of enstatite chondrites, of which the Earth is likely to be primarily composed of. It is also consistent with the model in which the Earth was initially formed as a completely volatile-free planet. The water and other volatile elements came later through the accretion of icy particles by the occasional scatterings in the outer regions. Our new proposed tandem planet formation regime shows that planetesimals are formed at two distinct sites (outer and inner edges of the MRI suppressed region). The former is likely to be the source of outer gas giants and the latter inner rocky planets. The tandem regime also explains the gap in the distribution of solid components (2-4 AU), which is necessary to form a ;solar-system-like; planetary system, which has a relatively small Mars and a very small mass in the main asteroid belt. We found that this tandem regime dose not take place when the vertical magnetic field of the disk five times weaker compared with that we assumed in the present paper, since the outer MRI front shift outward beyond 100 AU. This suggests that yet other regimes exists in our united theory. It may explain the variation observed in exsoplanetary systems by variations in magnetic field and probably angular momentum of the parent molecular cloud.

Historical trends of participation of women in robotic spacecraft missions

NASA Astrophysics Data System (ADS)

Rathbun, Julie A.; Dones, Luke; Gay, Pamela; Cohen, Barbara; Horst, Sarah; Lakdawalla, Emily; Spickard, James; Milazzo, Moses; Sayanagi, Kunio M.; Schug, Joanna

2015-11-01

For many planetary scientists, being involved in a spacecraft mission is the highlight of a career. Many young scientists hope to one day be involved in such a mission. We will look at the science teams of several flagship-class spacecraft missions to look for trends in the representation of groups that are underrepresented in science. We will start with The Galileo, Cassini, and Europa missions to the outer solar system as representing missions that began in the 1980s, 1990s and 2010s respectively. We would also like to extend our analysis to smaller missions and those to targets other than the outer solar system.

ScienceCast 54: Getting to Know the Goldilocks Planet

NASA Image and Video Library

2012-03-29

NASA's Kepler spacecraft is discovering a veritable avalanche of alien worlds. It seems to be just a matter of time before Kepler finds what astronomers are really looking for: an Earth-like planet orbiting its star in the "Goldilocks zone".

A suppression of differential rotation in Jupiter’s deep interior

NASA Astrophysics Data System (ADS)

Guillot, T.; Miguel, Y.; Militzer, B.; Hubbard, W. B.; Kaspi, Y.; Galanti, E.; Cao, H.; Helled, R.; Wahl, S. M.; Iess, L.; Folkner, W. M.; Stevenson, D. J.; Lunine, J. I.; Reese, D. R.; Biekman, A.; Parisi, M.; Durante, D.; Connerney, J. E. P.; Levin, S. M.; Bolton, S. J.

2018-03-01

Jupiter’s atmosphere is rotating differentially, with zones and belts rotating at speeds that differ by up to 100 metres per second. Whether this is also true of the gas giant’s interior has been unknown, limiting our ability to probe the structure and composition of the planet. The discovery by the Juno spacecraft that Jupiter’s gravity field is north–south asymmetric and the determination of its non-zero odd gravitational harmonics J3, J5, J7 and J9 demonstrates that the observed zonal cloud flow must persist to a depth of about 3,000 kilometres from the cloud tops. Here we report an analysis of Jupiter’s even gravitational harmonics J4, J6, J8 and J10 as observed by Juno and compared to the predictions of interior models. We find that the deep interior of the planet rotates nearly as a rigid body, with differential rotation decreasing by at least an order of magnitude compared to the atmosphere. Moreover, we find that the atmospheric zonal flow extends to more than 2,000 kilometres and to less than 3,500 kilometres, making it fully consistent with the constraints obtained independently from the odd gravitational harmonics. This depth corresponds to the point at which the electric conductivity becomes large and magnetic drag should suppress differential rotation. Given that electric conductivity is dependent on planetary mass, we expect the outer, differentially rotating region to be at least three times deeper in Saturn and to be shallower in massive giant planets and brown dwarfs.

Para hydrogen equilibration in the atmospheres of the outer planets

NASA Technical Reports Server (NTRS)

Conrath, Barney J.

1986-01-01

The thermodynamic behavior of the atmospheres of the Jovian planets is strongly dependent on the extent to which local thermal equilibration of the ortho and para states of molecular hydrogen is achieved. Voyager IRIS data from Jupiter imply substantial departures of the para hydrogen fraction from equilibrium in the upper troposphere at low latitudes, but with values approaching equilibrium at higher latitudes. Data from Saturn are less sensitive to the orth-para ratio, but suggest para hydrogen fractions near the equilibrium value. Above approximately the 200 K temperature level, para hydrogen conversion can enhance the efficiency of convection, resulting in a substantial increase in overturning times on all of the outer planets. Currently available data cannot definitively establish the ortho-para ratios in the atmospheres of Uranus and Neptune, but suggest values closer to local equilibrium than to the 3.1 normal ratio. Modeling of sub-millimeter wavelength measurements of these planets suggest thermal structures with frozen equilibrium lapse rates in their convective regions.

The Potential and Equipotentiality of Spacecraft

NASA Astrophysics Data System (ADS)

Afonin, V. V.

2004-01-01

The problem of maintenance of the equipotentiality of spacecraft surfaces is considered. The method under examination is the use of the ``conductive thermal-vacuum multilayer blanket'' (CMLB), whose outer surface represents a fabric woven of threads of glass fiber type with interwoven metal threads. The process of spacecraft potential formation and methods of the potential calculation are described, and the results of such a calculation for the illuminated and shadowed parts of spacecraft surfaces in some characteristic near-Earth plasma environments are presented. The CMLB model is described, and the potential distribution near the CMLB surface is calculated. The conclusion was drawn that the conductive thermal-vacuum multilayer blanket used in some cases on Russian spacecraft does not ensure the equipotentiality of spacecraft surfaces, and in the case of using CMLB, the differential spacecraft charging in outer regions of the Earth's magnetosphere may reach a dangerous level for onboard electronic systems. In spite of the fact that CMLB guards against large-scale powerful discharges, one cannot exclude discharges completely, what may result in broadband noise enhancement and cause onboard systems failures.

ARC-1979-AC79-0143-3

NASA Image and Video Library

1979-01-24

Photo by Voyager 1 (JPL) The spacecraft took this photo of the planet Jupiter on Jan 24, while still more than 25 million miles (40 million kilometers) away. As the spacecraft draws closer to the planet (about 1 million kilometers a day) more details are emergng in the turbulent clouds. The Great Red Spot shows prominently below center, surrounded by what scientists call a remarkably complex region of the giant planet's atmosphere. An elongated yellow cloud within the Great Red Spot is swirling around the spot's interior boundary in a counterclockwise direction with a period of a little less than six days, confirming the whirlpool-like circulation that astronomers have suspected from ground-based photographs. Ganymede, Jupiter's largest satellite, can be seen to the lower left of the planet. Ganymede is a planet-sized body larger than Mercury. This color photo was assembled at Jet Propulsion Laboratory's Image Processing Lab from there black and white images taken through filters. The Voyagers are managed for NASA's Office of Space Science by Jet Propulsion Laboratory. (ref: P-20945C Mission Image 1-9)

Study of spin-scan imaging for outer planets missions. [imaging techniques for Jupiter orbiter missions

NASA Technical Reports Server (NTRS)

Russell, E. E.; Chandos, R. A.; Kodak, J. C.; Pellicori, S. F.; Tomasko, M. G.

1974-01-01

The constraints that are imposed on the Outer Planet Missions (OPM) imager design are of critical importance. Imager system modeling analyses define important parameters and systematic means for trade-offs applied to specific Jupiter orbiter missions. Possible image sequence plans for Jupiter missions are discussed in detail. Considered is a series of orbits that allow repeated near encounters with three of the Jovian satellites. The data handling involved in the image processing is discussed, and it is shown that only minimal processing is required for the majority of images for a Jupiter orbiter mission.

Planetary/DOD entry technology flight experiments. Volume 2: Planetary entry flight experiments

NASA Technical Reports Server (NTRS)

Christensen, H. E.; Krieger, R. J.; Mcneilly, W. R.; Vetter, H. C.

1976-01-01

The technical feasibility of launching a high speed, earth entry vehicle from the space shuttle to advance technology for the exploration of the outer planets' atmospheres was established. Disciplines of thermodynamics, orbital mechanics, aerodynamics propulsion, structures, design, electronics and system integration focused on the goal of producing outer planet environments on a probe shaped vehicle during an earth entry. Major aspects of analysis and vehicle design studied include: planetary environments, earth entry environment capability, mission maneuvers, capabilities of shuttle upper stages, a comparison of earth entry planetary environments, experiment design and vehicle design.

Extended atmospheres of outer planet satellites and comets

NASA Technical Reports Server (NTRS)

Smyth, W. H.; Combi, M. R.

1985-01-01

Model analysis of the extended atmospheres of outer planet satellites and comets are discussed. Understanding the neutral hydrogen distribution in the Saturn system concentrated on assessing the spatial dependence of the lifetime of hydrogen atoms and on obtaining appropriately sorted Lyman ALPHA data from the Voyager 1 UVS instrument. Progress in the area of the extended cometary atmospheres included analysis of Pioneer Venus Layman alpha observations of Comet P/Encke with the fully refined hydrogen cloud model, development of the basic carbon and oxygen models, and planning for the Pioneer Venus UVS observations of Comets P/Giacobini-Zinner and P/Halley.

Electron impact cross-sections and cooling rates for methane. [in thermal balance of electrons in atmospheres and ionospheres of planets and satellites in outer solar system

NASA Technical Reports Server (NTRS)

Gan, L.; Cravens, T. E.

1992-01-01

Energy transfer between electrons and methane gas by collisional processes plays an important role in the thermal balance of electrons in the atmospheres and ionospheres of planets and satellites in the outer solar system. The literature is reviewed for electron impact cross-sections for methane in this paper. Energy transfer rates are calculated for elastic and inelastic processes using a Maxwellian electron distribution. Vibrational, rotational, and electronic excitation and ionization are included. Results are presented for a wide range of electron temperatures and neutral temperatures.

A Herschel-Detected Correlation between Planets and Debris Disks

NASA Astrophysics Data System (ADS)

Bryden, Geoffrey; Krist, J. E.; Stapelfeldt, K. R.; Kennedy, G.; Wyatt, M.; Beichman, C. A.; Eiroa, C.; Marshall, J.; Maldonado, J.; Montesinos, B.; Moro-Martin, A.; Matthews, B. C.; Fischer, D.; Ardila, D. R.; Kospal, A.; Rieke, G.; Su, K. Y.

2013-01-01

The Fomalhaut, beta Pic, and HR 8799 systems each have directly imaged planets and prominent debris disks, suggesting a direct link between the two phenomena. Unbiased surveys with Spitzer, however, failed to find a statistically significant correlation. We present results from SKARPS (the Search for Kuiper belts Around Radial-velocity Planet Stars) a Herschel far-IR survey for debris disks around solar-type stars known to have orbiting planets. The identified disks are generally cold and distant 50 K/100 AU), i.e. well separated from the radial-velocity-discovered planets. Nevertheless, we find a strong correlation between the inner planets and outer disks, with disks around planet-bearing stars tending to be much brighter than those not known to have planets.

Constraints on the Mass and Location of Planet 9 set by Range and VLBI Observations of Spacecraft at Saturn

NASA Astrophysics Data System (ADS)

Jacobson, Robert A.; Folkner, William M.; Park, Ryan S.; Williams, James G.

2017-06-01

Batygin and Brown, 2016 AJ, found that all Kuiper belt objects (KBOs) with well determined orbits having periods greater than 4000 years share nearly the same orbital plane and are apsidally aligned. They attribute this orbital clustering to the existence of a distant planet, Planet 9, well beyond Neptune, with a mass roughly ten times that of Earth. If such a planet exists, it would affect the motion of the known solar system planets, in particular Saturn, which is well observed with radiometric ranging from the Voyager and Cassini spacecraft and VLBI observations of Cassini. The current planetary ephemerides do not account for the postulated Planet 9, yet their fit to the observational data shows no obvious effect that could be attributed to neglecting that planet. However, it is possible that the effect could be absorbed by the estimated parameters used to determine the ephemerides. Those parameters include the planetary orbital elements, mass of the Sun, and the masses of the asteroids that perturb the Martian orbit. We recently updated the Voyager and Cassini data sets and extended the latter through 2017 March. We analyze the sensitivity of these data to the tidal perturbations caused by Planet 9 for a range of positions on the sky and tidal parameters (the ratio of the mass of Planet 9 to the cube of its distance from Saturn). We determine an upper bound on the tidal parameter and the most probable directions consistent with the observational data.

K2-155: A Bright Metal-poor M Dwarf with Three Transiting Super-Earths

NASA Astrophysics Data System (ADS)

Hirano, Teruyuki; Dai, Fei; Livingston, John H.; Fujii, Yuka; Cochran, William D.; Endl, Michael; Gandolfi, Davide; Redfield, Seth; Winn, Joshua N.; Guenther, Eike W.; Prieto-Arranz, Jorge; Albrecht, Simon; Barragan, Oscar; Cabrera, Juan; Cauley, P. Wilson; Csizmadia, Szilard; Deeg, Hans; Eigmüller, Philipp; Erikson, Anders; Fridlund, Malcolm; Fukui, Akihiko; Grziwa, Sascha; Hatzes, Artie P.; Korth, Judith; Narita, Norio; Nespral, David; Niraula, Prajwal; Nowak, Grzegorz; Pätzold, Martin; Palle, Enric; Persson, Carina M.; Rauer, Heike; Ribas, Ignasi; Smith, Alexis M. S.; Van Eylen, Vincent

2018-03-01

We report on the discovery of three transiting super-Earths around K2-155 (EPIC 210897587), a relatively bright early M dwarf (V = 12.81 mag) observed during Campaign 13 of the NASA K2 mission. To characterize the system and validate the planet candidates, we conducted speckle imaging and high-dispersion optical spectroscopy, including radial velocity measurements. Based on the K2 light curve and the spectroscopic characterization of the host star, the planet sizes and orbital periods are {1.55}-0.17+0.20 {R}\\oplus and 6.34365 ± 0.00028 days for the inner planet; {1.95}-0.22+0.27 {R}\\oplus and 13.85402 ± 0.00088 days for the middle planet; and {1.64}-0.17+0.18 {R}\\oplus and 40.6835 ± 0.0031 days for the outer planet. The outer planet (K2-155d) is near the habitable zone, with an insolation 1.67 ± 0.38 times that of the Earth. The planet’s radius falls within the range between that of smaller rocky planets and larger gas-rich planets. To assess the habitability of this planet, we present a series of three-dimensional global climate simulations, assuming that K2-155d is tidally locked and has an Earth-like composition and atmosphere. We find that the planet can maintain a moderate surface temperature if the insolation proves to be smaller than ∼1.5 times that of the Earth. Doppler mass measurements, transit spectroscopy, and other follow-up observations should be rewarding, as K2-155 is one of the optically brightest M dwarfs known to harbor transiting planets.

MEASURING THE MASS OF SOLAR SYSTEM PLANETS USING PULSAR TIMING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Champion, D. J.; Hobbs, G. B.; Manchester, R. N.

High-precision pulsar timing relies on a solar system ephemeris in order to convert times of arrival (TOAs) of pulses measured at an observatory to the solar system barycenter. Any error in the conversion to the barycentric TOAs leads to a systematic variation in the observed timing residuals; specifically, an incorrect planetary mass leads to a predominantly sinusoidal variation having a period and phase associated with the planet's orbital motion about the Sun. By using an array of pulsars (PSRs J0437-4715, J1744-1134, J1857+0943, J1909-3744), the masses of the planetary systems from Mercury to Saturn have been determined. These masses are consistentmore » with the best-known masses determined by spacecraft observations, with the mass of the Jovian system, 9.547921(2) x10{sup -4} M {sub sun}, being significantly more accurate than the mass determined from the Pioneer and Voyager spacecraft, and consistent with but less accurate than the value from the Galileo spacecraft. While spacecraft are likely to produce the most accurate measurements for individual solar system bodies, the pulsar technique is sensitive to planetary system masses and has the potential to provide the most accurate values of these masses for some planets.« less

Impact Site: Cassini's Final Image

NASA Image and Video Library

2017-09-15

This monochrome view is the last image taken by the imaging cameras on NASA's Cassini spacecraft. It looks toward the planet's night side, lit by reflected light from the rings, and shows the location at which the spacecraft would enter the planet's atmosphere hours later. A natural color view, created using images taken with red, green and blue spectral filters, is also provided (Figure 1). The imaging cameras obtained this view at approximately the same time that Cassini's visual and infrared mapping spectrometer made its own observations of the impact area in the thermal infrared. This location -- the site of Cassini's atmospheric entry -- was at this time on the night side of the planet, but would rotate into daylight by the time Cassini made its final dive into Saturn's upper atmosphere, ending its remarkable 13-year exploration of Saturn. The view was acquired on Sept. 14, 2017 at 19:59 UTC (spacecraft event time). The view was taken in visible light using the Cassini spacecraft wide-angle camera at a distance of 394,000 miles (634,000 kilometers) from Saturn. Image scale is about 11 miles (17 kilometers). The original image has a size of 512x512 pixels. A movie is available at https://photojournal.jpl.nasa.gov/catalog/PIA21895

Return to the Red Planet

NASA Technical Reports Server (NTRS)

Lee, W.

1996-01-01

In November 1996, NASA and the Jet Propulsion Laboratory will begin America's return to Mars after a 20-year absence by launching the Mars Global Surveyor (MGS) spacecraft. This mission will usher in a new and exciting era of scientific missions to study the red planet.

ScienceCast 123: What Happened to Mars? A Planetary Mystery

NASA Image and Video Library

2013-11-08

Mars was once on track to become a thriving Earth-like planet, yet today it is an apparently lifeless wasteland. A NASA spacecraft named MAVEN will soon journey to Mars to find out what went wrong on the Red Planet.

KSC-2009-1016

NASA Image and Video Library

2009-01-06

CAPE CANAVERAL, Fla. -- The shipping container holding the Kepler spacecraft is placed on the tarmac outside Astrotech in Titusville, Fla., before being moved inside. A NASA Discovery mission, Kepler is specifically designed to survey our region of the Milky Way galaxy to discover hundreds of Earth-size and smaller planets in or near the habitable zone and determine how many of the billions of stars in our galaxy have such planets. Results from this mission will allow us to place our solar system within the continuum of planetary systems in the Galaxy. The spacecraft will be processed at Astrotech before being carried to its launch pad at Cape Canaveral. .NASA's planet-hunting Kepler mission is scheduled to launch no earlier than March 5, 2009, atop a Delta II rocket. Photo credit: NASA/Kim Shiflett

KSC-2009-1017

NASA Image and Video Library

2009-01-06

CAPE CANAVERAL, Fla. -- The shipping container holding the Kepler spacecraft is placed on the tarmac outside Astrotech in Titusville, Fla., before being moved inside. A NASA Discovery mission, Kepler is specifically designed to survey our region of the Milky Way galaxy to discover hundreds of Earth-size and smaller planets in or near the habitable zone and determine how many of the billions of stars in our galaxy have such planets. Results from this mission will allow us to place our solar system within the continuum of planetary systems in the Galaxy. The spacecraft will be processed at Astrotech before being carried to its launch pad at Cape Canaveral. .NASA's planet-hunting Kepler mission is scheduled to launch no earlier than March 5, 2009, atop a Delta II rocket. Photo credit: NASA/Kim Shiflett

Juno View of Jupiter Southern Lights

NASA Image and Video Library

2016-09-02

This infrared image gives an unprecedented view of the southern aurora of Jupiter, as captured by NASA's Juno spacecraft on August 27, 2016. The planet's southern aurora can hardly be seen from Earth due to our home planet's position in respect to Jupiter's south pole. Juno's unique polar orbit provides the first opportunity to observe this region of the gas-giant planet in detail. Juno's Jovian Infrared Auroral Mapper (JIRAM) camera acquired the view at wavelengths ranging from 3.3 to 3.6 microns -- the wavelengths of light emitted by excited hydrogen ions in the polar regions. The view is a mosaic of three images taken just minutes apart from each other, about four hours after the perijove pass while the spacecraft was moving away from Jupiter. http://photojournal.jpl.nasa.gov/catalog/PIA21033

Secular dynamics of multiplanetary circumbinary systems: stationary solutions and binary-planet secular resonance

NASA Astrophysics Data System (ADS)

Andrade-Ines, Eduardo; Robutel, Philippe

2018-01-01

We present an analytical formalism to study the secular dynamics of a system consisting of N-2 planets orbiting a binary star in outer orbits. We introduce a canonical coordinate system and expand the disturbing function in terms of canonical elliptic elements, combining both Legendre polynomials and Laplace coefficients, to obtain a general formalism for the secular description of this type of configuration. With a quadratic approximation of the development, we present a simplified analytical solution for the planetary orbits for both the single planet and the two-planet cases. From the two-planet model, we show that the inner planet accelerates the precession rate of the binary pericenter, which, in turn, may enter in resonance with the secular frequency of the outer planet, characterizing a secular resonance. We calculate an analytical expression for the approximate location of this resonance and apply it to known circumbinary systems, where we show that it can occur at relatively close orbits, for example at 2.4 au for the Kepler-38 system. With a more refined model, we analyse the dynamics of this secular resonance and we show that a bifurcation of the corresponding fixed points can affect the long- term evolution and stability of planetary systems. By comparing our results with complete integrations of the exact equations of motion, we verified the accuracy of our analytical model.

Observational Constraints on the Orbit and Location of Planet Nine in the Outer Solar System

NASA Astrophysics Data System (ADS)

Brown, Michael E.; Batygin, Konstantin

2016-06-01

We use an extensive suite of numerical simulations to constrain the mass and orbit of Planet Nine, the recently proposed perturber in a distant eccentric orbit in the outer solar system. We compare our simulations to the observed population of aligned eccentric high semimajor axis Kuiper belt objects (KBOs) and determine which simulation parameters are statistically compatible with the observations. We find that only a narrow range of orbital elements can reproduce the observations. In particular, the combination of semimajor axis, eccentricity, and mass of Planet Nine strongly dictates the semimajor axis range of the orbital confinement of the distant eccentric KBOs. Allowed orbits, which confine KBOs with semimajor axis beyond 380 au, have perihelia roughly between 150 and 350 au, semimajor axes between 380 and 980 au, and masses between 5 and 20 Earth masses. Orbitally confined objects also generally have orbital planes similar to that of the planet, suggesting that the planet is inclined approximately 30°to the ecliptic. We compare the allowed orbital positions and estimated brightness of Planet Nine to previous and ongoing surveys which would be sensitive to the planet’s detection and use these surveys to rule out approximately two-thirds of the planet’s orbit. Planet Nine is likely near aphelion with an approximate brightness of 22< V< 25. At opposition, its motion, mainly due to parallax, can easily be detected within 24 hours.

A Low Mass for Mars from Jupiter's Early Gas-Driven Migration

NASA Technical Reports Server (NTRS)

Walsh, Kevin J.; Morbidelli, Alessandro; Raymond, Sean N.; O'Brien, David P.; Mandell, Avi M.

2011-01-01

Jupiter and Saturn formed in a few million years from a gas-dominated protoplanetary disk, and were susceptible to gas-driven migration of their orbits on timescales of only approximately 100,000 years. Hydrodynamic simulations show that these giant planets can undergo a two-stage, inward-then-outward, migration. The terrestrial planets finished accreting much later and their characteristics, including Mars' small mass, are best reproduced by starting from a planetesimal disk with an outer edge at about one astronomical unit from the Sun (1 AU is the Earth-Sun distance). Here we report simulations of the early Solar System that show how the inward migration of Jupiter to 1.5 AU, and its subsequent outward migration, lead to a planetesimal disk truncated at 1 AU; the terrestrial planets then form from this disk over the next 30-50 million years, with an Earth/Mars mass ratio consistent with observations. Scattering by Jupiter initially empties but then repopulates the asteroid belt, with inner-belt bodies originating between 1 and 3 AU and outer-belt bodies originating between and beyond the giant planets. This explains the significant compositional differences across the asteroid belt. The key aspect missing from previous models of terrestrial planet formation is the substantial radial migration of the giant planets, which suggests that their behaviour is more similar to that inferred for extrasolar planets than previously thought.

Initialization of distributed spacecraft for precision formation flying

NASA Technical Reports Server (NTRS)

Hadaegh, F. Y.; Scharf, D. P.; Ploen, S. R.

2003-01-01

In this paper we present a solution to the formation initialization problem for N distributed spacecraft located in deep space. Our solution to the FI problem is based on a three-stage sky search procedure that reduces the FI problem for N spacecraft to the simpler problem of initializing a set of sub-formations. We demonstrate our FI algorithm in simulation using NASA's five spacecraft Terrestrial Planet Finder mission as an example.

The Hera Saturn entry probe mission

NASA Astrophysics Data System (ADS)

Mousis, O.; Atkinson, D. H.; Spilker, T.; Venkatapathy, E.; Poncy, J.; Frampton, R.; Coustenis, A.; Reh, K.; Lebreton, J.-P.; Fletcher, L. N.; Hueso, R.; Amato, M. J.; Colaprete, A.; Ferri, F.; Stam, D.; Wurz, P.; Atreya, S.; Aslam, S.; Banfield, D. J.; Calcutt, S.; Fischer, G.; Holland, A.; Keller, C.; Kessler, E.; Leese, M.; Levacher, P.; Morse, A.; Muñoz, O.; Renard, J.-B.; Sheridan, S.; Schmider, F.-X.; Snik, F.; Waite, J. H.; Bird, M.; Cavalié, T.; Deleuil, M.; Fortney, J.; Gautier, D.; Guillot, T.; Lunine, J. I.; Marty, B.; Nixon, C.; Orton, G. S.; Sánchez-Lavega, A.

2016-10-01

The Hera Saturn entry probe mission is proposed as an M-class mission led by ESA with a contribution from NASA. It consists of one atmospheric probe to be sent into the atmosphere of Saturn, and a Carrier-Relay spacecraft. In this concept, the Hera probe is composed of ESA and NASA elements, and the Carrier-Relay Spacecraft is delivered by ESA. The probe is powered by batteries, and the Carrier-Relay Spacecraft is powered by solar panels and batteries. We anticipate two major subsystems to be supplied by the United States, either by direct procurement by ESA or by contribution from NASA: the solar electric power system (including solar arrays and the power management and distribution system), and the probe entry system (including the thermal protection shield and aeroshell). Hera is designed to perform in situ measurements of the chemical and isotopic compositions as well as the dynamics of Saturn's atmosphere using a single probe, with the goal of improving our understanding of the origin, formation, and evolution of Saturn, the giant planets and their satellite systems, with extrapolation to extrasolar planets. Hera's aim is to probe well into the cloud-forming region of the troposphere, below the region accessible to remote sensing, to the locations where certain cosmogenically abundant species are expected to be well mixed. By leading to an improved understanding of the processes by which giant planets formed, including the composition and properties of the local solar nebula at the time and location of giant planet formation, Hera will extend the legacy of the Galileo and Cassini missions by further addressing the creation, formation, and chemical, dynamical, and thermal evolution of the giant planets, the entire solar system including Earth and the other terrestrial planets, and formation of other planetary systems.

Juno Approach to the Earth-Moon System

NASA Image and Video Library

2013-12-10

This frame from a movie was captured by a star tracker camera on NASA Jupiter-bound Juno spacecraft. It was taken over several days as Juno approached Earth for a close flyby that would send the spacecraft onward to the giant planet.

Design and Verification of External Occulters for Direct Imaging of Extrasolar Planets

NASA Technical Reports Server (NTRS)

Cady, Eric

2011-01-01

An occulter is an optical element which is placed in front of the telescope to block most of the light from a star before it reaches the optics inside, without blocking the planet.In our case, we use two spacecraft ying in formation: First has its edge shaped to cancel the starlight Second is the telescope which images the star and planet

The Mars Climate Orbiter arrives at KSC to begin final preparations for launch

NASA Technical Reports Server (NTRS)

1998-01-01

The Mars Climate Orbiter spacecraft is moved into the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2) in KSC's industrial area. It arrived at the Shuttle Landing Facility aboard an Air Force C-17 cargo plane early this morning following its flight from the Lockheed Martin Astronautics plant in Denver, Colo. When it arrives at the red planet, the Mars Climate Orbiter will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (1.8 Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Delta II 7425 rocket.

NASA and the search for life in the universe.

PubMed

Dick, Steven J

2006-06-01

Almost from its beginnings in 1958, the National Aeronautics and Space Administration (NASA) set up a life-science program. Because one of the priorities of the organization is to search for life beyond Earth, NASA began designing spacecraft to unravel the mysteries of Mars. The effort to search for life on Mars culminated in the landing of two Viking spacecraft on the surface of the planet in 1976. Although the biology experiments conducted as part of these missions provided some evidence for the possibility of life, the scientific consensus was that they drew a blank. In 1996, however, the 'Mars rock' rekindled interest in life in our solar system. The discovery of an ocean on the Jovian moon Europa, of organic molecules on the Saturnian moon Titan and persuasive evidence that water once flowed on Mars suggests that the solar system is still of considerable exobiological interest. In addition, since 1995 approximately 175 planets have been found beyond our solar system. Although these discoveries are gas giants, NASA spacecraft might soon detect Earth-sized planets. The search for life in the universe continues.

The Mars Climate Orbiter arrives at KSC to begin final preparations for launch

NASA Technical Reports Server (NTRS)

1998-01-01

The Mars Climate Orbiter spacecraft is moved onto a flatbed for transport to the Spacecraft Assembly and Encapsulation Facility-2 (SAEF-2). It arrived at KSC's Shuttle Landing Facility aboard an Air Force C-17 cargo plane early this morning following its flight from the Lockheed Martin Astronautics plant in Denver, Colo. When it arrives at the red planet, the Mars Climate Orbiter will primarily support its companion Mars Polar Lander spacecraft, planned for launch on Jan. 3, 1999. After that, the Mars Climate Orbiter's instruments will monitor the Martian atmosphere and image the planet's surface on a daily basis for one Martian year (1.8 Earth years). It will observe the appearance and movement of atmospheric dust and water vapor, as well as characterize seasonal changes on the surface. The detailed images of the surface features will provide important clues to the planet's early climate history and give scientists more information about possible liquid water reserves beneath the surface. The scheduled launch date for the Mars Climate Orbiter is Dec. 10, 1998, on a Delta II 7425 rocket.

Shadow Below

NASA Image and Video Library

2016-06-20

As Saturn's northern hemisphere summer approaches, the shadows of the rings creep ever southward across the planet. Here, the ring shadows appear to obscure almost the entire southern hemisphere, while the planet's north pole and its six-sided jet stream, known as "the hexagon," are fully illuminated by the sun. When NASA's Cassini spacecraft arrived at Saturn 12 years ago, the shadows of the rings lay far to the north on the planet (see PIA06077). As the mission progressed and seasons turned on the slow-orbiting giant, equinox arrived and the shadows of the rings became a thin line at the equator (see PIA11667). This view looks toward the sunlit side of the rings from about 16 degrees above the ring plane. The image was taken in red light with the Cassini spacecraft wide-angle camera on March 19, 2016. The view was obtained at a distance of approximately 1.7 million miles (2.7 million kilometers) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 92 degrees. Image scale is 100 miles (160 kilometers) per pixel. http://photojournal.jpl.nasa.gov/catalog/PIA20486

Polarized Disk Emission from Herbig Ae/Be Stars Observed Using Gemini Planet Imager: HD 144432, HD 150193, HD 163296, and HD 169142

DOE Office of Scientific and Technical Information (OSTI.GOV)

Monnier, John D.; Aarnio, Alicia; Adams, Fred C.

In order to look for signs of ongoing planet formation in young disks, we carried out the first J -band polarized emission imaging of the Herbig Ae/Be stars HD 150193, HD 163296, and HD 169142 using the Gemini Planet Imager, along with new H band observations of HD 144432. We confirm the complex “double ring” structure for the nearly face-on system HD 169142 first seen in H -band, finding the outer ring to be substantially redder than the inner one in polarized intensity. Using radiative transfer modeling, we developed a physical model that explains the full spectral energy distribution andmore » J - and H -band surface brightness profiles, suggesting that the differential color of the two rings could come from reddened starlight traversing the inner wall and may not require differences in grain properties. In addition, we clearly detect an elongated, off-center ring in HD 163296 (MWC 275), locating the scattering surface to be 18 au above the midplane at a radial distance of 77 au, co-spatial with a ring seen at 1.3 mm by ALMA linked to the CO snow line. Lastly, we report a weak tentative detection of scattered light for HD 150193 (MWC 863) and a non-detection for HD 144432; the stellar companion known for each of these targets has likely disrupted the material in the outer disk of the primary star. For HD 163296 and HD 169142, the prominent outer rings we detect could be evidence for giant planet formation in the outer disk or a manifestation of large-scale dust growth processes possibly related to snow-line chemistry.« less

Circus Family of Stars (Artist's Concept)

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site] Quick Time Movie for PIA03521 Circus Family of Stars

This artist's animation shows the clockwork-like orbits of a triple-star system called HD 188753, which was discovered to harbor a gas giant, or 'hot Jupiter,' planet. The planet zips around the system's main star (yellow, center) every 3.3 days, while the main star is circled every 25.7 years by a dancing duo of stars (yellow and orange, outer orbit). The star pair is locked in a 156-day orbit.

This eccentric star family is a cramped bunch; the distance between the main star and the outer pair of stars is about the same as that between the Sun and Saturn. Though multiple-star systems like this one are common in the universe, astronomers were surprised to find a planet living in such tight quarters.

One reason for the surprise has to do with theories of hot Jupiter formation. Astronomers believe that these planets begin life at the outer fringes of their stars, in thick dusty disks called protoplanetary disks, before migrating inward. The discovery of a world under three suns throws this theory into question. As seen in this animation, there is not much room at this system's outer edges for a hot Jupiter to grow.

The discovery was made using the Keck I telescope atop Mauna Kea mountain in Hawaii. The triple-star system is located 149 light-years away in the constellation Cygnus.

The sizes and orbital periods in the animation are not shown to scale. The relative motions are shown with respect to the main star.

Scattering V-type asteroids during the giant planet instability: a step for Jupiter, a leap for basalt

NASA Astrophysics Data System (ADS)

Brasil, P. I. O.; Roig, F.; Nesvorný, D.; Carruba, V.

2017-06-01

V-type asteroids are a taxonomic class whose surface is associated with a basaltic composition. The only known source of V-type asteroids in the Main Asteroid Belt is (4) Vesta, which is located in the inner part of the Main Belt. However, many V-type asteroids cannot be dynamically linked to Vesta, in particular, those asteroids located in the middle and outer parts of the Main Belt. Previous works have failed to find mechanisms to transport V-type asteroids from the inner to the middle and outer belts. In this work, we propose a dynamical mechanism that could have acted on primordial asteroid families. We consider a model of the giant planet migration known as the jumping Jupiter model with five planets. Our study is focused on the period of 10 Myr that encompasses the instability phase of the giant planets. We show that, for different hypothetical Vesta-like paleo-families in the inner belt, the perturbations caused by the ice giant that is scattered into the asteroid belt before being ejected from the Solar system are able to scatter V-type asteroids to the middle and outer belts. Based on the orbital distribution of V-type candidates identified from the Sloan Digital Sky Survey and the VISTA Survey colours, we show that this mechanism is efficient enough provided that the hypothetical paleo-family originated from a 100 to 500 km crater excavated on the surface of (4) Vesta. This mechanism is able to explain the currently observed V-type asteroids in the middle and outer belts, with the exception of (1459) Magnya.

14 CFR 1216.305 - Actions requiring environmental assessments.

Code of Federal Regulations, 2013 CFR

2013-01-01

... prepare an EA. (b) Typical NASA actions normally requiring an EA include: (1) Specific spacecraft... altering the ongoing operations at a NASA Center which could lead directly, indirectly, or cumulatively to... solar system bodies (such as asteroids, comets, planets, dwarf planets, and planetary moons), which...

A Planetary System Exploration Project for Introductory Astronomy and Astrobiology Courses

NASA Astrophysics Data System (ADS)

Rees, Richard F.

2015-01-01

I have created three-part projects for the introductory astronomy and astrobiology courses at Westfield State University which simulate the exploration of a fictional planetary system. The introductory astronomy project is an initial reconnaissance of the system by a robotic spacecraft, culminating in close flybys of two or three planets. The astrobiology project is a follow-up mission concluding with the landing of a roving lander on a planet or moon. Student responses in earlier parts of each project can be used to determine which planets are targeted for closer study in later parts. Highly realistic views of the planets from space and from their surfaces can be created using programs such as Celestia and Terragen; images and video returned by the spacecraft are thus a highlight of the project. Although designed around the particular needs and mechanics of the introductory astronomy and astrobiology courses for non-majors at WSU, these projects could be adapted for use in courses at many different levels.

Newest Member of Our Solar System Artist Concept

NASA Image and Video Library

2005-08-03

This artist concept shows the planet catalogued as 2003UB313 at the lonely outer fringes of our solar system. Our Sun can be seen in the distance. The new planet is at least as big as Pluto and about three times farther away from the Sun than Pluto.

Acetylene Fermentation: Relevance to Primordial Biogeochemistry and the Search for Life in the Outer Solar System

NASA Astrophysics Data System (ADS)

Oremland, R. S.; Baesman, S. M.; Miller, L. G.

2014-02-01

Acetylene supports the growth of some terrestrial anaerobes. The reaction is highly exothermic. The abundance of acetylene in the methane-rich planet(oid)s of the outer solar system could represent a means of nourishment for resident alien microbes.

Unveiling Mercury's Mysteries with BepiColombo - an ESA/JAXA Mission to Explore the Innermost Planet of our Solar System

NASA Astrophysics Data System (ADS)

Benkhoff, J.

2017-12-01

NASA's MESSENGER mission has fundamentally changed our view of the innermost planet. Mercury is in many ways a very different planet from what we were expecting. Now BepiColombo has to follow up on answering the fundamental questions that MESSENGER raised and go beyond. BepiColombo is a joint project between the European Space Agency (ESA) and the Japanese Aerospace Exploration Agency (JAXA). The Mission consists of two orbiters, the Mercury Planetary Orbiter (MPO) and the Mercury Magnetospheric Orbiter (MMO). The mission scenario foresees a launch of both spacecraft with an ARIANE V in October 2018 and an arrival at Mercury in 2025. From their dedicated orbits the two spacecraft will be studying the planet and its environment. BepiColombo will study and understand the composition, geophysics, atmosphere, magnetosphere and history of Mercury, the least explored planet in the inner Solar System. In addition, the BepiColombo mission will provide a rare opportunity to collect multi-point measurements in a planetary environment. This will be particularly important at Mercury because of short temporal and spatial scales in the Mercury's environment. The foreseen orbits of the MPO and MMO will allow close encounters of the two spacecrafts throughout the mission. The MPO scientific payload comprises eleven instruments/instrument packages; The MMO comprises 5 instruments/instrument packages to the the study of the environment. The MPO will focus on a global characterization of Mercury through the investigation of its interior, surface, exosphere and magnetosphere. In addition, it will be testing Einstein's theory of general relativity. Together, the scientific payload of both spacecraft will provide the detailed information necessary to understand Mercury and its magnetospheric environment and to find clues to the origin and evolution of a planet close to its parent star. The BepiColombo mission will complement and follow up the work of NASA's MESSENGER mission by providing a highly accurate and comprehensive set of observations of Mercury. The mission has been named in honor of Giuseppe (Bepi) Colombo (1920-1984), who was a brilliant Italian mathematician, who made many significant contributions to planetary research and celestial mechanics.

An experiment to study energetic particle fluxes in and beyond the earth's outer magnetosphere

NASA Technical Reports Server (NTRS)

Anderson, K. A.; Lin, R. P.; Paoli, R. J.; Parks, G. K.; Lin, C. S.; Reme, H.; Bosqued, J. M.; Martel, F.; Cotin, F.; Cros, A.

1978-01-01

This experiment is designed to take advantage of the ISEE Mother/Daughter dual spacecraft system to study energetic particle phenomena in the earth's outer magnetosphere and beyond. Large geometric factor fixed voltage electrostatic analyzers and passively cooled semiconductor detector telescopes provide high time resolution coverage of the energy range from 1.5 to 300 keV for both ions and electrons. Essentially identical instrumentation is placed on the two spacecraft to separate temporal from spatial effects in the observed particle phenomena.

Long-lived particulate or gaseous structure in Saturn's outer magnetosphere

NASA Technical Reports Server (NTRS)

Lazarus, A. J.; Hasegawa, T.; Bagenal, F.

1983-01-01

Voyager 1 and 2 and Pioneer 11 data on the variations in the number density of low-energy plasma ions in the outer Saturn magnetosphere are discussed. Low and high latitude observations are compared in reference to the position of the spacecraft crossing of the field line. Abrupt decreases in the number density interrupted the tendancy for the number density to increase with spacecraft approach to Saturn. All three spacecraft are concluded to have encountered the same magnetospheric structure in the field line, with absorbers being present in the equatorial plane. The absorbers are suggested to be either gas or debris, which may be detectable visibly or with occultation techniques.

The Pan-Pacific Planet Search. II. Confirmation of a Two-planet System around HD 121056

NASA Astrophysics Data System (ADS)

Wittenmyer, Robert A.; Wang, Liang; Liu, Fan; Horner, Jonathan; Endl, Michael; Johnson, John Asher; Tinney, C. G.; Carter, B. D.

2015-02-01

Precise radial velocities from the Anglo-Australian Telescope (AAT) confirm the presence of a rare short-period planet around the K0 giant HD 121056. An independent two-planet solution using the AAT data shows that the inner planet has P = 89.1 ± 0.1 days, and m sin i = 1.35 ± 0.17 MJup. These data also confirm the planetary nature of the outer companion, with m sin i = 3.9 ± 0.6 MJup and a = 2.96 ± 0.16 AU. HD 121056 is the most-evolved star to host a confirmed multiple-planet system, and is a valuable example of a giant star hosting both a short-period and a long-period planet.

Volatile components and continental material of planets

NASA Technical Reports Server (NTRS)

Florenskiy, K. P.; Nikolayeva, O. V.

1986-01-01

It is shown that the continental material of the terrestrial planets varies in composition from planet to planet according to the abundances and composition of true volatiles (H20, CO2, etc.) in the outer shells of the planets. The formation of these shells occurs very early in a planet's evolution when the role of endogenous processes is indistinct and continental materials are subject to melting and vaporizing in the absence of an atmosphere. As a result, the chemical properties of continental materials are related not only to fractionation processes but also to meltability and volatility. For planets retaining a certain quantity of true volatile components, the chemical transformation of continental material is characterized by a close interaction between impact melting vaporization and endogeneous geological processes.

Red Spot Spotted by Juno

NASA Image and Video Library

2016-06-30

NASA's Juno spacecraft obtained this color view on June 28, 2016, at a distance of 3.9 million miles (6.2 million kilometers) from Jupiter. As Juno nears its destination, features on the giant planet are increasingly visible, including the Great Red Spot. The spacecraft is approaching over Jupiter's north pole, providing a unique perspective on the Jupiter system, including its four large moons. The scene was captured by the mission's imaging camera, called JunoCam, which is designed to acquire high resolution views of features in Jupiter's atmosphere from very close to the planet. http://photojournal.jpl.nasa.gov/catalog/PIA20705

Soaring Over Jupiter

NASA Image and Video Library

2017-09-21

This striking image of Jupiter was captured by NASA's Juno spacecraft as it performed its eighth flyby of the gas giant planet. The image was taken on Sept. 1, 2017 at 2:58 p.m. PDT (5:58 p.m. EDT). At the time the image was taken, the spacecraft was 4,707 miles (7,576 kilometers) from the tops of the clouds of the planet at a latitude of about -17.4 degrees. Citizen scientist Gerald Eichstädt processed this image using data from the JunoCam imager. Points of interest are "Whale's Tail" and "Dan's Spot." https://photojournal.jpl.nasa.gov/catalog/PIA21966

Evaluation of optical data for Mars approach navigation.

NASA Technical Reports Server (NTRS)

Jerath, N.

1972-01-01

Investigation of several optical data types which can be obtained from science and engineering instruments normally aboard interplanetary spacecraft. TV cameras are assumed to view planets or satellites and stars for celestial references. Also, spacecraft attitude sensors are assumed to yield celestial references. The investigation of approach phases of typical Mars missions showed that the navigation accuracy was greatly enhanced with the addition of optical data to radio data. Viewing stars and the planet Mars was found most advantageous ten days before Mars encounter, and viewing Deimos or Phobos and stars was most advantageous within ten days of encounter.

Falling Away from Jupiter

NASA Image and Video Library

2018-02-07

This image of Jupiter's southern hemisphere was captured by NASA's Juno spacecraft as it performed a close flyby of the gas giant planet on Dec. 16, 2017. Juno captured this color-enhanced image at 10:24 a.m. PST (1:24 p.m. EST) when the spacecraft was about 19,244 miles (30,970 kilometers) from the tops of Jupiter's clouds at a latitude of 49.9 degrees south -- roughly halfway between the planet's equator and its south pole. Citizen scientist Gerald Eichstädt processed this image using data from the JunoCam imager. https://photojournal.jpl.nasa.gov/catalog/PIA21977

MARINER 10 LAUNCH VEHICLE ATLAS CENTAUR 34 UNDERGOES TANKING TEST AT LAUNCH COMPLEX 36B

NASA Technical Reports Server (NTRS)

1973-01-01

Atlas Centaur 34, undergoes tanking test on NASA Complex 36B at Cape Kennedy, Fla. Atlas Centaur 34 is under preparation to launch history's first duel-planet flight, the Mariner mission to Venus and Mercury, scheduled for early November. With all events going as planned, the Mariner spacecraft will fly by Venus in early February, 1974, and reach Mercury in late march, 1974. The spacecraft, Mariner 10, will carry two television cameras to photograph the planets, and six other scientific experiments to return planetary and interplanetary data back to Earth.

InSight Spacecraft Uncrating, Removal from Container, Lift Heat

NASA Image and Video Library

2018-03-01

Inside the Astrotech processing facility at Vandenberg Air Force Base in California, technicians and engineers use a crane to move the heatshield for NASA's Interior Exploration using Seismic Investigations, Geodesy and Heat Transport, or InSight, spacecraft for further testing. InSight was developed and built by Lockheed-Martin Space Systems in Denver, Colorado, and is scheduled for liftoff is May 5, 2018. InSight is the first mission to land on Mars and explore the Red Planet's deep interior. It will investigate processes that shaped the rocky planets of the inner solar system including Earth.

An Empirically Derived Three-Dimensional Laplace Resonance in the GJ 876 Planetary System

NASA Astrophysics Data System (ADS)

Nelson, Benjamin Earl; Robertson, Paul; Pritchard, Seth

2015-08-01

We report constraints on the three-dimensional orbital architecture for all four planets known to orbit the nearby M dwarf Gliese 876 (=GJ 876) based solely on Doppler measurements and demanding long-term orbital stability. Our dataset incorporates publicly available radial velocities taken with the ELODIE and CORALIE spectrographs, HARPS, and Keck HIRES as well as previously unpublished HIRES RVs. We first quantitatively assess the validity of the planets thought to orbit GJ 876 by computing the Bayes factors for a variety of different coplanar models using an importance sampling algorithm. We confirm that a four-planet model is indeed preferred over a three-planet model. Next, we apply a Newtonian MCMC algorithm (RUN DMC, B. Nelson et al. 2014) to perform a Bayesian analysis of the planet masses and orbits using an n-body model that allows each planet to take on its own orbit in three-dimensional space. Based on the radial velocities alone, the mutual inclinations for the outer three resonant planets are constrained to Φcb = 2.8±1.71.3 degrees for the "c" and "b" pair and Φbe = 10.3±6.35.1 degrees for the "b" and "e" pair. We integrate the equations of motion of a sample of initial conditions drawn from our posterior for 107 years. We identify dynamically unstable models and find that the GJ 876 planets must be roughly coplanar (Φcb = 1.41±0.620.57 degrees) and (Φbe = 3.9±2.01.9 degrees), indicating the amount of planet-planet scattering in the system has been low. We investigate the distribution of the respective resonant arguments of each planet pair and find that at least one resonant argument for each planet pair and the Laplace argument librate. The libration amplitudes in our three-dimensional orbital model supports the idea of the outer-three planets having undergone significant past disk migration.

Multi-Planetary Systems: Observations and Models of Dynamical Interactions

NASA Technical Reports Server (NTRS)

Lissauer, Jack J.

2018-01-01

More than 600 multi-planet systems are known. The vast majority of these systems have been discovered by NASA's Kepler spacecraft, but dozens were found using the Doppler technique, the first multi-exoplanet system was identified through pulsar timing, and the most massive system has been found using imaging. More than one-third of the 4000+ planet candidates found by NASA's Kepler spacecraft are associated with target stars that have more than one planet candidate, and the large number of such Kepler "multis" tells us that flat multiplanet systems like our Solar System are common. Virtually all of Kepler candidate multis are stable, as tested by numerical integrations that assume a physically motivated mass-radius relationship. Statistical studies performed on these candidate systems reveal a great deal about the architecture of planetary systems, including the typical spacing of orbits and flatness. The characteristics of several of the most interesting confirmed multi-exoplanet systems will also be discussed.HR 8799's four massive planets orbit tens of AU from their host star and travel on nearly circular orbits. PSR B1257+12 has three much smaller planets orbiting close to a neutron star. Both represent extremes and show that planet formation is a robust process that produces a diversity of outcomes. Although both exomoons and Trojan (triangle Lagrange point) planets have been searched for, neither has yet been found.

14 CFR § 1216.305 - Actions requiring environmental assessments.

Code of Federal Regulations, 2014 CFR

2014-01-01

... prepare an EA. (b) Typical NASA actions normally requiring an EA include: (1) Specific spacecraft... altering the ongoing operations at a NASA Center which could lead directly, indirectly, or cumulatively to... solar system bodies (such as asteroids, comets, planets, dwarf planets, and planetary moons), which...

Ceres Sharper Than Ever Animation

NASA Image and Video Library

2015-01-27

This frame from an animation of the dwarf planet Ceres was made by combining images taken by the Dawn spacecraft on January 25, 2015. These images of Ceres, and they represent the highest-resolution views to date of the dwarf planet. http://photojournal.jpl.nasa.gov/catalog/PIA19171

Studies of the major planet satellite systems

NASA Technical Reports Server (NTRS)

Frey, H.; Lowman, P. D.

1974-01-01

A summary is presented of the available data on the satellites of the major planets, including the currently most plausible models for several observed phenomena, for the planning of spacecraft missions to these objects. Some of the important questions likely to be solved by flyby and/or orbital missions to the giant planets are detailed, the importance of these studies to our understanding of the solar system as a whole is indicated.

3-D orbital evolution model of outer asteroid belt

NASA Technical Reports Server (NTRS)

Solovaya, Nina A.; Gerasimov, Igor A.; Pittich, Eduard M.

1992-01-01

The evolution of minor planets in the outer part of the asteroid belt is considered. In the framework of the semi-averaged elliptic restricted three-dimensional three-body model, the boundary of regions of the Hill's stability is found. As was shown in our work, the Jacobian integral exists.

KSC-2009-1025

NASA Image and Video Library

2009-01-06

CAPE CANAVERAL, Fla. -- At the Astrotech payload processing facility in Titusville, Fla., NASA's Kepler spacecraft is rolled into a clean room. The spacecraft will be rotated to vertical, uncovered and prepared for initial testing. A NASA Discovery mission, Kepler is specifically designed to survey our region of the Milky Way galaxy to discover hundreds of Earth-size and smaller planets in or near the habitable zone and determine how many of the billions of stars in our galaxy have such planets. Results from this mission will allow us to place our solar system within the continuum of planetary systems in the Galaxy. After processing at Astrotech, Kepler will be carried to its launch pad at Cape Canaveral. NASA's planet-hunting Kepler mission is scheduled to launch no earlier than March 5 atop a Delta II rocket. Photo credit: NASA/Chris Rhodes

KSC-2009-1024

NASA Image and Video Library

2009-01-06

CAPE CANAVERAL, Fla. -- At the Astrotech payload processing facility in Titusville, Fla., NASA's Kepler spacecraft is rolled out of its shipping container. The spacecraft will be rotated to vertical, uncovered and prepared for initial testing. A NASA Discovery mission, Kepler is specifically designed to survey our region of the Milky Way galaxy to discover hundreds of Earth-size and smaller planets in or near the habitable zone and determine how many of the billions of stars in our galaxy have such planets. Results from this mission will allow us to place our solar system within the continuum of planetary systems in the Galaxy. After processing at Astrotech, Kepler will be carried to its launch pad at Cape Canaveral. NASA's planet-hunting Kepler mission is scheduled to launch no earlier than March 5 atop a Delta II rocket. Photo credit: NASA/Chris Rhodes

KSC-2009-1022

NASA Image and Video Library

2009-01-06

CAPE CANAVERAL, Fla. -- At the Astrotech payload processing facility in Titusville, Fla., the open doors of the shipping container reveal NASA's Kepler spacecraft. After removal from the container, the spacecraft will be rotated to vertical, uncovered and prepared for initial testing. A NASA Discovery mission, Kepler is specifically designed to survey our region of the Milky Way galaxy to discover hundreds of Earth-size and smaller planets in or near the habitable zone and determine how many of the billions of stars in our galaxy have such planets. Results from this mission will allow us to place our solar system within the continuum of planetary systems in the Galaxy. After processing at Astrotech, Kepler will be carried to its launch pad at Cape Canaveral. NASA's planet-hunting Kepler mission is scheduled to launch no earlier than March 5 atop a Delta II rocket. Photo credit: NASA/Chris Rhodes

Laboratory studies of low temperature rate coefficients: The atmospheric chemistry of the outer planets

NASA Technical Reports Server (NTRS)

Leone, Stephen R.

1992-01-01

The purpose of the project is to perform laboratory measurements of reaction rate coefficients at low temperature. The reactions and temperatures of interest are those that are important in the chemistry of the hydrocarbon rich atmospheres of the outer planets and their satellites. In this stage of the study we are investigating reactions of ethynyl radicals, C2H, with acetylene (C2H2), methane (CH4), and hydrogen (H2). In the previous status report from 24 Jan. 1992, we reported on the development of the experimental apparatus and the first, preliminary data for the C2H + C2H2 reaction.

Test evaluation of potential heatshield contamination of an outer planet probe's gas sampling system

NASA Technical Reports Server (NTRS)

Kessler, W. C.

1975-01-01

The feasibility of retaining the heat shield for outer planet probes was investigated as a potential source of atmospheric sample contamination by outgassing. The onboard instruments which are affected by the concept are the pressure sensor, temperature sensor, IR detector, nephelometer, and gas sampling instruments. It was found that: (1) The retention of the charred heatshield and the baseline atmospheric sampling concepts are compatible with obtaining noncontaminated atmospheric samples. (2) Increasing the sampling tube length so that it extends beyond the viscous boundary layer eliminates contamination of the atmospheric sample. (3) The potential for contamination increases with angle of attack.

Laboratory evaluation and application of microwave absorption properties under simulated conditions for planetary atmospheres

NASA Technical Reports Server (NTRS)

Steffes, Paul G.

1987-01-01

Laboratory measurements were conducted to evaluate properties of atmospheric gases under simulated conditions for the outer planets. A significant addition to this effort was the capability to make such measurements at millimeter wavelengths. Measurements should soon be completed on the millimeter wave absorption from ammonia under Jovian conditions. Also studied will be the feasibility of measuring the microwave and millimeter wave properties of phosphine (PH3) under simulated Jovian conditions. Further analysis and application of the laboratory results to microwave and millimeter wave absorption data for the outer planet, such as Voyager Radio Occultation experiments, will be pursued.

BepiColombo — The Next Step of Mercury Exploration with Two Orbiting Spacecraft

NASA Astrophysics Data System (ADS)

Benkhoff, J.

2018-05-01

BepiColombo is a joint project between ESA and JAXA. The mission consists of two orbiters — the Mercury Planetary Orbiter and the Mercury Magnetospheric Orbiter. From dedicated orbits, the spacecraft will be studying the planet and its environment.

Large-scale solar wind flow around Saturn's nonaxisymmetric magnetosphere

NASA Astrophysics Data System (ADS)

Sulaiman, A. H.; Jia, X.; Achilleos, N.; Sergis, N.; Gurnett, D. A.; Kurth, W. S.

2017-09-01

The interaction between the solar wind and a magnetosphere is central to the dynamics of a planetary system. Here we address fundamental questions on the large-scale magnetosheath flow around Saturn using a 3-D magnetohydrodynamic (MHD) simulation. We find Saturn's polar-flattened magnetosphere to channel 20% more flow over the poles than around the flanks at the terminator. Further, we decompose the MHD forces responsible for accelerating the magnetosheath plasma to find the plasma pressure gradient as the dominant driver. This is by virtue of a high-β magnetosheath and, in turn, the high-MA bow shock. Together with long-term magnetosheath data by the Cassini spacecraft, we present evidence of how nonaxisymmetry substantially alters the conditions further downstream at the magnetopause, crucial for understanding solar wind-magnetosphere interactions such as reconnection and shear flow-driven instabilities. We anticipate our results to provide a more accurate insight into the global conditions upstream of Saturn and the outer planets.

PADME (Phobos And Deimos and Mars Environment): A Proposed NASA Discovery Mission to Investigate the Two Moons of Mars

NASA Technical Reports Server (NTRS)

Lee, Pascal; Benna, Mehdi; Britt, Daniel; Colaprete, Anthony; Davis, Warren; Delory, Greg; Elphic, Richard; Fulsang, Ejner; Genova, Anthony; Glavin, Daniel;

KSC-2011-2440

NASA Image and Video Library

2011-03-23

CAPE CANAVERAL, Fla. -- Technicians in the Astrotech payload processing facility in Titusville, Fla., test the electrical continuity of a solar array that will help power NASA's Juno spacecraft on a mission to Jupiter. Power-generating panels on three sets of solar arrays will extend outward from Juno’s hexagonal body, giving the overall spacecraft a span of more than 66 feet in order to operate at such a great distance from the sun. Juno is scheduled to launch aboard an Atlas V rocket from Cape Canaveral, Fla., on Aug. 5, 2011, reaching Jupiter in July 2016. The spacecraft will orbit the giant planet more than 30 times, skimming to within 3,000 miles above its cloud tops, for about one year. With its suite of science instruments, the spacecraft will investigate the existence of a solid planetary core, map Jupiter's intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet's auroras. For more information visit, www.nasa.gov/juno. Photo credit: NASA/Jack Pfaller

KSC-2011-2443

NASA Image and Video Library

2011-03-23

CAPE CANAVERAL, Fla. -- Technicians in the Astrotech payload processing facility in Titusville, Fla., test the electrical continuity of a solar array that will help power NASA's Juno spacecraft on a mission to Jupiter. Power-generating panels on three sets of solar arrays will extend outward from Juno’s hexagonal body, giving the overall spacecraft a span of more than 66 feet in order to operate at such a great distance from the sun. Juno is scheduled to launch aboard an Atlas V rocket from Cape Canaveral, Fla., on Aug. 5, 2011, reaching Jupiter in July 2016. The spacecraft will orbit the giant planet more than 30 times, skimming to within 3,000 miles above its cloud tops, for about one year. With its suite of science instruments, the spacecraft will investigate the existence of a solid planetary core, map Jupiter's intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet's auroras. For more information visit, www.nasa.gov/juno. Photo credit: NASA/Jack Pfaller

KSC-2011-2488

NASA Image and Video Library

2011-03-26

CAPE CANAVERAL, Fla. -- Technicians in the Astrotech payload processing facility in Titusville, Fla., unfurl solar array No. 1 with a magnetometer boom that will help power NASA's Juno spacecraft on a mission to Jupiter. Power-generating panels on three sets of solar arrays will extend outward from Juno’s hexagonal body, giving the overall spacecraft a span of more than 66 feet in order to operate at such a great distance from the sun. Juno is scheduled to launch aboard an Atlas V rocket from Cape Canaveral, Fla., on Aug. 5, 2011, reaching Jupiter in July 2016. The spacecraft will orbit the giant planet more than 30 times, skimming to within 3,000 miles above its cloud tops, for about one year. With its suite of science instruments, the spacecraft will investigate the existence of a solid planetary core, map Jupiter's intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet's auroras. For more information visit, www.nasa.gov/juno. Photo credit: NASA/Jack Pfaller

KSC-2011-2325

NASA Image and Video Library

2011-03-16

TITUSVILLE, Fla. -- A solar panel that will help power NASA's Juno spacecraft on a mission to Jupiter is unpacked in the Astrotech payload processing facility in Titusville, Fla. Power-generating panels on three sets of solar arrays will extend outward from Juno’s hexagonal body, giving the overall spacecraft a span of more than 66 feet in order to operate at such a great distance from the sun. Juno is scheduled to launch aboard an Atlas V rocket from Cape Canaveral, Fla., on Aug. 5, 2011, reaching Jupiter in July 2016. The spacecraft will orbit the giant planet more than 30 times, skimming to within 3,000 miles above its cloud tops, for about one year. With its suite of science instruments, the spacecraft will investigate the existence of a solid planetary core, map Jupiter's intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet's auroras. For more information visit, www.nasa.gov/juno. Photo credit: NASA/Jack Pfaller

KSC-2011-2487

NASA Image and Video Library

2011-03-26

CAPE CANAVERAL, Fla. -- Technicians in the Astrotech payload processing facility in Titusville, Fla., begin to unfurl solar array No. 1 with a magnetometer boom that will help power NASA's Juno spacecraft on a mission to Jupiter. Power-generating panels on three sets of solar arrays will extend outward from Juno’s hexagonal body, giving the overall spacecraft a span of more than 66 feet in order to operate at such a great distance from the sun. Juno is scheduled to launch aboard an Atlas V rocket from Cape Canaveral, Fla., on Aug. 5, 2011, reaching Jupiter in July 2016. The spacecraft will orbit the giant planet more than 30 times, skimming to within 3,000 miles above its cloud tops, for about one year. With its suite of science instruments, the spacecraft will investigate the existence of a solid planetary core, map Jupiter's intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet's auroras. For more information visit, www.nasa.gov/juno. Photo credit: NASA/Jack Pfaller

KSC-2011-2326

NASA Image and Video Library

2011-03-16

TITUSVILLE, Fla. -- Technicians in the Astrotech payload processing facility in Titusville, Fla., unpack a solar panel that will help power NASA's Juno spacecraft on a mission to Jupiter. Power-generating panels on three sets of solar arrays will extend outward from Juno’s hexagonal body, giving the overall spacecraft a span of more than 66 feet in order to operate at such a great distance from the sun. Juno is scheduled to launch aboard an Atlas V rocket from Cape Canaveral, Fla., on Aug. 5, 2011, reaching Jupiter in July 2016. The spacecraft will orbit the giant planet more than 30 times, skimming to within 3,000 miles above its cloud tops, for about one year. With its suite of science instruments, the spacecraft will investigate the existence of a solid planetary core, map Jupiter's intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet's auroras. For more information visit, www.nasa.gov/juno. Photo credit: NASA/Jack Pfaller

KSC-2011-2339

NASA Image and Video Library

2011-03-17

CAPE CANAVERAL, Fla. -- Technicians in the Astrotech payload processing facility in Titusville, Fla., begin processing a solar panel that will help power NASA's Juno spacecraft on a mission to Jupiter. Power-generating panels on three sets of solar arrays will extend outward from Juno’s hexagonal body, giving the overall spacecraft a span of more than 66 feet in order to operate at such a great distance from the sun. Juno is scheduled to launch aboard an Atlas V rocket from Cape Canaveral, Fla., on Aug. 5, 2011, reaching Jupiter in July 2016. The spacecraft will orbit the giant planet more than 30 times, skimming to within 3,000 miles above its cloud tops, for about one year. With its suite of science instruments, the spacecraft will investigate the existence of a solid planetary core, map Jupiter's intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet's auroras. For more information visit, www.nasa.gov/juno. Photo credit: NASA/Jack Pfaller

KSC-2011-2486

NASA Image and Video Library

2011-03-26

CAPE CANAVERAL, Fla. -- Technicians in the Astrotech payload processing facility in Titusville, Fla., prepare to unfurl solar array No. 1 with a magnetometer boom that will help power NASA's Juno spacecraft on a mission to Jupiter. Power-generating panels on three sets of solar arrays will extend outward from Juno’s hexagonal body, giving the overall spacecraft a span of more than 66 feet in order to operate at such a great distance from the sun. Juno is scheduled to launch aboard an Atlas V rocket from Cape Canaveral, Fla., on Aug. 5, 2011, reaching Jupiter in July 2016. The spacecraft will orbit the giant planet more than 30 times, skimming to within 3,000 miles above its cloud tops, for about one year. With its suite of science instruments, the spacecraft will investigate the existence of a solid planetary core, map Jupiter's intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet's auroras. For more information visit, www.nasa.gov/juno. Photo credit: NASA/Jack Pfaller

KSC-2011-2491

NASA Image and Video Library

2011-03-26

CAPE CANAVERAL, Fla. -- Technicians in the Astrotech payload processing facility in Titusville, Fla., unfurl solar array No. 1 with a magnetometer boom that will help power NASA's Juno spacecraft on a mission to Jupiter. Power-generating panels on three sets of solar arrays will extend outward from Juno’s hexagonal body, giving the overall spacecraft a span of more than 66 feet in order to operate at such a great distance from the sun. Juno is scheduled to launch aboard an Atlas V rocket from Cape Canaveral, Fla., on Aug. 5, 2011, reaching Jupiter in July 2016. The spacecraft will orbit the giant planet more than 30 times, skimming to within 3,000 miles above its cloud tops, for about one year. With its suite of science instruments, the spacecraft will investigate the existence of a solid planetary core, map Jupiter's intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet's auroras. For more information visit, www.nasa.gov/juno. Photo credit: NASA/Jack Pfaller

KSC-2011-2484

NASA Image and Video Library

2011-03-26

CAPE CANAVERAL, Fla. -- Technicians in the Astrotech payload processing facility in Titusville, Fla., prepare to unfurl solar array No. 1 with a magnetometer boom that will help power NASA's Juno spacecraft on a mission to Jupiter. Power-generating panels on three sets of solar arrays will extend outward from Juno’s hexagonal body, giving the overall spacecraft a span of more than 66 feet in order to operate at such a great distance from the sun. Juno is scheduled to launch aboard an Atlas V rocket from Cape Canaveral, Fla., on Aug. 5, 2011, reaching Jupiter in July 2016. The spacecraft will orbit the giant planet more than 30 times, skimming to within 3,000 miles above its cloud tops, for about one year. With its suite of science instruments, the spacecraft will investigate the existence of a solid planetary core, map Jupiter's intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet's auroras. For more information visit, www.nasa.gov/juno. Photo credit: NASA/Jack Pfaller

KSC-2011-2438

NASA Image and Video Library

2011-03-23

CAPE CANAVERAL, Fla. -- Technicians in the Astrotech payload processing facility in Titusville, Fla., prepare to test the electrical continuity of a solar array that will help power NASA's Juno spacecraft on a mission to Jupiter. Power-generating panels on three sets of solar arrays will extend outward from Juno’s hexagonal body, giving the overall spacecraft a span of more than 66 feet in order to operate at such a great distance from the sun. Juno is scheduled to launch aboard an Atlas V rocket from Cape Canaveral, Fla., on Aug. 5, 2011, reaching Jupiter in July 2016. The spacecraft will orbit the giant planet more than 30 times, skimming to within 3,000 miles above its cloud tops, for about one year. With its suite of science instruments, the spacecraft will investigate the existence of a solid planetary core, map Jupiter's intense magnetic field, measure the amount of water and ammonia in the deep atmosphere, and observe the planet's auroras. For more information visit, www.nasa.gov/juno. Photo credit: NASA/Jack Pfaller