Sulfuric Acid on Europa

NASA Image and Video Library

1999-09-30

Frozen sulfuric acid on Jupiter's moon Europa is depicted in this image produced from data gathered by NASA's Galileo spacecraft. The brightest areas, where the yellow is most intense, represent regions of high frozen sulfuric acid concentration. Sulfuric acid is found in battery acid and in Earth's acid rain. This image is based on data gathered by Galileo's near infrared mapping spectrometer. Europa's leading hemisphere is toward the bottom right, and there are enhanced concentrations of sulfuric acid in the trailing side of Europa (the upper left side of the image). This is the face of Europa that is struck by sulfur ions coming from Jupiter's innermost moon, Io. The long, narrow features that crisscross Europa also show sulfuric acid that may be from sulfurous material extruded in cracks. http://photojournal.jpl.nasa.gov/catalog/PIA02500

Europa, taken from Voyager 1 to Jupiter

NASA Image and Video Library

1979-03-01

Range : 5.9 million kilometers (3.66 million miles) Europa is Jupiter's 2nd Galilean satellites from the planet and the brightest. Photo taken early morning through violet filter. Faint swirls and linear patterns show in the equatorial region (which shows darker than the poles). This hemisphere always faces Jupiter. North is up. Density and size comparable to Earth's Moon and seems to show water ice or ground water on its surface. JPL Reference # P-21163.

Europa Explorer: A Mission to Explore Europa and Investigate Its Habitability

NASA Astrophysics Data System (ADS)

Clark, K. B.; Pappalardo, R. T.; Greeley, R.

2007-12-01

Europa is the astrobiological archetype for icy satellite habitability, with a warm, salty, water ocean with plausible chemical energy sources. It is also a geophysical wonderland of interrelated ice shell processes that are intimately related to the ocean and tides, and of complex interactions among its interior, surface, atmosphere, and particles and fields environments. In 2007, NASA commissioned a study of a flagship-class mission to Europa, with the aim of launching as early as 2015. The difficulty of this type of mission, primarily due to the propulsive requirements and Jupiter's trapped radiation, led to many previous studies which investigated various approaches to meeting the science objectives. The Europa Explorer is a mature orbiter concept to explore Europa and investigate its habitability, fulfilling objectives laid out by the National Research Council's Planetary Science Decadal Survey. The mission examines Europa's ocean, ice shell, chemistry, geology, external environment, and neighborhood. With a nominal launch in June 2015, the flight system arrives at Jupiter in 6 years using a Venus- Earth-Earth Gravity Assist trajectory. It would orbit Jupiter for 2 years using gravity assists of the icy Galilean satellites to lower its energy, providing the opportunity for significant Jupiter system science. It would then enter Europa orbit at an altitude of 100-200 km, where it would perform science investigations for 1 year. A campaign- based operations scenario has been developed which permits return of 5.4 Tbits of science data beginning in July 2021, and emphasizing the highest priority Europa science objectives early in the orbital phase of the mission. The baseline mission concept includes 11 instruments that address high-priority investigations while providing the flexibility to respond to discoveries. A less ambitious mission has also been evaluated which has 8 instruments and returns about a third of the data with 6 months of orbital operations at

Europa Broken Ice

NASA Image and Video Library

1997-09-07

Jupiter moon Europa, as seen in this image taken June 27, 1996 by NASA Galileo spacecraft, displays features in some areas resembling ice floes seen in Earth polar seas. http://photojournal.jpl.nasa.gov/catalog/PIA00291

Natural radio emission of Jupiter as interferences for radar investigations of the icy satellites of Jupiter

NASA Astrophysics Data System (ADS)

Cecconi, B.; Hess, S.; Hérique, A.; Santovito, M. R.; Santos-Costa, D.; Zarka, P.; Alberti, G.; Blankenship, D.; Bougeret, J.-L.; Bruzzone, L.; Kofman, W.

2012-02-01

Radar instruments are part of the core payload of the two Europa Jupiter System Mission (EJSM) spacecraft: NASA-led Jupiter Europa Orbiter (JEO) and ESA-led Jupiter Ganymede Orbiter (JGO). At this point of the project, several frequency bands are under study for radar, which ranges between 5 and 50 MHz. Part of this frequency range overlaps with that of the natural jovian radio emissions, which are very intense in the decametric range, below 40 MHz. Radio observations above 40 MHz are free of interferences, whereas below this threshold, careful observation strategies have to be investigated. We present a review of spectral intensity, variability and sources of these radio emissions. As the radio emissions are strongly beamed, it is possible to model the visibility of the radio emissions, as seen from the vicinity of Europa or Ganymede. We have investigated Io-related radio emissions as well as radio emissions related to the auroral oval. We also review the radiation belts synchrotron emission characteristics. We present radio sources visibility products (dynamic spectra and radio source location maps, on still frames or movies), which can be used for operation planning. This study clearly shows that a deep understanding of the natural radio emissions at Jupiter is necessary to prepare the future EJSM radar instrumentation. We show that this radio noise has to be taken into account very early in the observation planning and strategies for both JGO and JEO. We also point out possible synergies with RPW (Radio and Plasma Waves) instrumentations.

Natural radio emission of Jupiter as interferences for radar investigations of the icy satellites of Jupiter

NASA Astrophysics Data System (ADS)

Cecconi, B.; Hess, S.; Hérique, A.; Santovito, M. R.; Santos-Costa, D.; Zarka, P.; Alberti, G.; Blankenship, D.; Bougeret, J. L.; Bruzzone, L.; Kofman, W.

2011-10-01

Radar instruments are part of the core payload of the two Europa Jupiter System Mission (EJSM) spacecraft: NASA-led Jupiter Europa Orbiter (JEO) and ESA-led Jupiter Ganymede Orbiter (JGO). At this point of the project, several frequency bands are under study for radar, which ranges between 5MHz and 50MHz. Part of this frequency range overlaps with that of the natural Jovian radio emissions, which are very intense in the decametric range, below 40 MHz. Radio observations above 40 MHz are free of interferences, whereas below this threshold, careful observation strategies have to be investigated. We present a review of spectral intensity, variability and sources of these radio emissions. As the radio emission are strongly beamed, it is possible to model the visibility of the radio emissions, as seen from the vicinity of Europa or Ganymede. We have investigated Io-related radio emissions as well as radio emissions related to the auroral oval. We also review the radiation belts synchrotron emission characteristics. We present radio sources visibility products (dynamic spectra and radio source location maps, on still frames or movies), which can be used for operation planning. This study clearly shows that a deep understanding of the natural radio emissions at Jupiter is necessary to prepare the future EJSM radar instrumentation. We show that this radio noise has to be taken into account very early in the observation planning and strategies for both JGO and JEO. We also point out possible synergies with RPW (Radio and Plasma Waves) instrumentations.

Europa In Color

NASA Image and Video Library

1997-09-07

False color has been used here to enhance the visibility of certain features in this composite of three images of the Minos Linea region on Jupiter moon Europa taken on 28 June 1996 by NASA Galileo spacecraft. http://photojournal.jpl.nasa.gov/catalog/PIA00275

Ultraviolet emissions from the magnetic footprints of Io, Ganymede and Europa on Jupiter.

PubMed

Clarke, J T; Ajello, J; Ballester, G; Ben Jaffel, L; Connerney, J; Gérard, J-C; Gladstone, G R; Grodent, D; Pryor, W; Trauger, J; Waite, J H

2002-02-28

Io leaves a magnetic footprint on Jupiter's upper atmosphere that appears as a spot of ultraviolet emission that remains fixed underneath Io as Jupiter rotates. The specific physical mechanisms responsible for generating those emissions are not well understood, but in general the spot seems to arise because of an electromagnetic interaction between Jupiter's magnetic field and the plasma surrounding Io, driving currents of around 1 million amperes down through Jupiter's ionosphere. The other galilean satellites may also leave footprints, and the presence or absence of such footprints should illuminate the underlying physical mechanism by revealing the strengths of the currents linking the satellites to Jupiter. Here we report persistent, faint, far-ultraviolet emission from the jovian footprints of Ganymede and Europa. We also show that Io's magnetic footprint extends well beyond the immediate vicinity of Io's flux-tube interaction with Jupiter, and much farther than predicted theoretically; the emission persists for several hours downstream. We infer from these data that Ganymede and Europa have persistent interactions with Jupiter's magnetic field despite their thin atmospheres.

Jupiter and Three Galilean Satellites

NASA Image and Video Library

1999-03-06

Jupiter, its Great Red Spot and three of its four largest satellites are visible in this photo taken Feb. 5, 1979, by Voyager 1. Io, Europa, and Callisto are seen against Jupiter disk. http://photojournal.jpl.nasa.gov/catalog/PIA00358

Ruddy Freckles on Europa

NASA Image and Video Library

2002-10-30

Reddish spots and shallow pits pepper the enigmatic ridged surface of Europa in this view combining information from images taken by NASA Galileo spacecraft during two different orbits around Jupiter.

Europa Imaging Highlights during GEM

NASA Technical Reports Server (NTRS)

1998-01-01

During the two year Galileo Europa Mission (GEM), NASA's Galileo spacecraft will focus intensively on Jupiter's intriguing moon, Europa. This montage shows samples of some of the features that will be imaged during eight successive orbits. The images in this montage are in order of increasing orbit from the upper left (orbit 11) to the lower right (orbit 19).

DESCRIPTIONS AND APPROXIMATE RESOLUTIONSTriple bands and dark spots

1.6 kilometers/pixelConamara Chaos

1.6 kilometers/pixelMannan'an Crater

1.6 kilometers/ pixelCilix

1.6 kilometers/pixelAgenor Linea and Thrace Macula

2 kilometers/pixelSouth polar terrain

2 kilometers/pixelRhadamanthys Linea

1.6 kilometers/pixelEuropa plume search

7 kilometers/pixel

1. Triple bands and dark spots were the focus of some images from Galileo's eleventh orbit of Jupiter. Triple bands are multiple ridges with dark deposits along the outer margins. Some extend for thousands of kilometers across Europa's icy surface. They are cracks in the ice sheet and indicate the great stresses imposed on Europa by tides raised by Jupiter, as well as Europa's neighboring moons, Ganymede and Io. The dark spots or 'lenticulae' are spots of localized disruption.

2. The Conamara Chaos region reveals icy plates which have broken up, moved, and rafted into new positions. This terrain suggests that liquid water or ductile ice was present near the surface. On Galileo's twelfth orbit of Jupiter, sections of this region with resolutions as high as 10 meters per picture element will be obtained.

3. Mannann'an Crater is a feature newly discovered by Galileo in June 1996. Color and high resolution images (to 40 meters per picture element) from Galileo's fourteenth orbit of Jupiter will offer a close look at the crater and help characterize how impacts affect the icy surface of this moon.

4. Cilix, a large mound about 1.5 kilometers high, is the center of Europa's coordinate system. Its concave top and what may be flow

Space Weathering Perspectives on Europa Amidst the Tempest of the Jupiter Magnetospheric System

NASA Technical Reports Server (NTRS)

Cooper, J. F.; Hartle, R. E.; Lipatov, A. S.; Sittler, E. C.; Cassidy, T. A.; Ip. W.-H.

2010-01-01

Europa resides within a "perfect storm" tempest of extreme external field, plasma, and energetic particle interactions with the magnetospheric system of Jupiter. Missions to Europa must survive, functionally operate, make useful measurements, and return critical science data, while also providing full context on this ocean moon's response to the extreme environment. Related general perspectives on space weathering in the solar system are applied to mission and instrument science requirements for Europa.

Jupiter Europa Orbiter Architecture Definition Process

NASA Technical Reports Server (NTRS)

Rasmussen, Robert; Shishko, Robert

2011-01-01

The proposed Jupiter Europa Orbiter mission, planned for launch in 2020, is using a new architectural process and framework tool to drive its model-based systems engineering effort. The process focuses on getting the architecture right before writing requirements and developing a point design. A new architecture framework tool provides for the structured entry and retrieval of architecture artifacts based on an emerging architecture meta-model. This paper describes the relationships among these artifacts and how they are used in the systems engineering effort. Some early lessons learned are discussed.

High Resolution Globe of Jupiter

NASA Image and Video Library

2001-01-30

This true-color simulated view of Jupiter is composed of 4 images taken by NASA's Cassini spacecraft on December 7, 2000. To illustrate what Jupiter would have looked like if the cameras had a field-of-view large enough to capture the entire planet, the cylindrical map was projected onto a globe. The resolution is about 144 kilometers (89 miles) per pixel. Jupiter's moon Europa is casting the shadow on the planet. https://photojournal.jpl.nasa.gov/catalog/PIA02873

Exobiological Exploration of Europa (E3) Europa Lander

NASA Technical Reports Server (NTRS)

Stillwagen, F. H.; Manvi, Ramachandra; Seywald, Hans; Park, Sang-Young; Kolacinski, Rick

2002-01-01

The search for life outside Earth's protected atmosphere is a compelling testament to the quest by mankind to determine if "we" are alone in the universe. The phenomenal success of the NASA Galileo spacecraft has indicated that the moons of Jupiter, and most notably Europa, may indeed contain subsurface liquid under an icy surface. This speculation of a salty liquid subsurface fuels expert opinions that biological products may exist. The Revolutionary Aerospace Systems Concepts (RASC) effort at Langley Research Center, initiated by NASA Headquarters, pushes NASA and the Aerospace/Science community to target advanced evolutionary technology usage to provide a Europa Lander concept targeted for completion within the next 50 years. The study effort indicates the use of certain advanced technologies to achieve a subsurface penetrator and liquid explorer in the approximately 2040 timeframe.

"Sniffing" Jupiter's moon Europa through ground-based IR observations

NASA Astrophysics Data System (ADS)

Paganini, Lucas; Mumma, Michael J.; Hurford, Terry; Roth, Lorenz; Villanueva, Geronimo Luis

2016-10-01

The ability to sample possible plumes from the subsurface ocean in Europa represents a major step in our search for extraterrestrial life. If plumes exist, sampling the effluent material would provide insights into their chemistry and relevant information about the prospect that life could exist, or now exists, within the ocean. Most of the difficulties in detecting plumes come from the less frequent observational coverage of Europa, which contrasts strongly with the frequent Cassini flybys of Enceladus (Spencer & Nimmo 2013). Recent observations have been taken with HST/STIS in 2014/2015, but results have shown no evident confirmation of the 2012 plume detection (Roth et al. 2014, 2015). Future in situ observations (Europa Mission) will provide definitive insights, but not before the spacecraft's arrival in ~2025, thus an interim approach is needed to inform such space mission planning and to complement existing observations at other wavelengths.In 2015, we initiated a strong campaign to build a comprehensive survey of possible plumes on Europa through high-resolution IR spectroscopy with Keck/NIRSPEC. We were awarded 10 nights out of 15 total nights available for Key Strategic Mission Support projects for the 2016A, 2016B, 2017A, and 2017B semesters under NASA time with the Keck Observatory. In 2016A, we observed Europa during 10 half-nights and will continue to do so for another 10 half-nights in 2017A. We target a serendipitous search of gaseous activity from Europa to confirm and constrain the chemical composition of possible Europan plumes that can aid the investigation of physical processes underlying (or on) its surface. Ultimately, we seek to: (1) provide information that can inform planning for NASA's Europa mission, (2) further our current understanding of Europa's gas environment, and (3) complement studies that are currently underway with other facilities (like the Hubble Space Telescope). In this presentation, we will discuss preliminary results

Hubble Sees Recurring Plume Erupting From Europa

NASA Image and Video Library

2017-04-13

These composite images show a suspected plume of material erupting two years apart from the same location on Jupiter's icy moon Europa. The images bolster evidence that the plumes are a real phenomenon, flaring up intermittently in the same region on the satellite. Both plumes, photographed in ultraviolet light by NASA's Hubble's Space Telescope Imaging Spectrograph, were seen in silhouette as the moon passed in front of Jupiter. The newly imaged plume, shown at right, rises about 62 miles (100 kilometers) above Europa's frozen surface. The image was taken Feb. 22, 2016. The plume in the image at left, observed by Hubble on March 17, 2014, originates from the same location. It is estimated to be about 30 miles (50 kilometers) high. The snapshot of Europa, superimposed on the Hubble image, was assembled from data from NASA's Galileo mission to Jupiter. The plumes correspond to the location of an unusually warm spot on the moon's icy crust, seen in the late 1990s by the Galileo spacecraft (see PIA21444). Researchers speculate that this might be circumstantial evidence for water venting from the moon's subsurface. The material could be associated with the global ocean that is believed to be present beneath the frozen crust. https://photojournal.jpl.nasa.gov/catalog/PIA21443

Various Landscapes and Features on Europa

NASA Technical Reports Server (NTRS)

1997-01-01

These 15 frames show the great variety of surface features on Jupiter's icy moon, Europa, which have been revealed by the Galileo spacecraft Solid State Imaging (CCD) system during its first six orbits around Jupiter from June 1996 to February 1997. North is to the top of each of the images. The features seen on Europa's surface document both internal and external processes shaping the icy crust. Internal processes and the possible presence of liquid water beneath the ice are indicated by features such as 'dark spots', lobe-shaped flow features, 'puddles','mottled terrain', knobs, pits, and the darker areas along ridges and triple bands.

Europa is subjected to constant tugging from the giant planet, Jupiter, as well as from its neighboring moons, Io and Ganymede. This causes 'tidal' forces that affect Europa's interior and surface. Evidence for such forces includes ridges, fractures, wedge-shaped bands, and areas of 'chaos'. Some of these features result from alternate extension and compression buckling and pulling apart Europa's icy shell.

Impact craters document external effects on a planet's surface. Although present on Europa, impact craters are relatively scarce compared to the number seen on Ganymede, Callisto, and on the surfaces of most other 'rocky' planets and moons in our solar system. This scarcity of craters suggests that the surface of Europa is very young. 'Maculae' on Europa may be the scars from large impact events.

These images have resolutions from 27 meters (89 feet) to 7 kilometers (4.3 miles) per picture element (pixel) and were taken by Galileo at ranges of 2,500 kilometers (1,525 miles) to 677,000 kilometers (413,000 miles) from Europa.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web

Modeling Europa's dust plumes

NASA Astrophysics Data System (ADS)

Southworth, B. S.; Kempf, S.; Schmidt, J.

2015-12-01

The discovery of Jupiter's moon Europa maintaining a probably sporadic water vapor plume constitutes a huge scientific opportunity for NASA's upcoming mission to this Galilean moon. Measuring properties of material emerging from interior sources offers a unique chance to understand conditions at Europa's subsurface ocean. Exploiting results obtained for the Enceladus plume, we simulate possible Europa plume configurations, analyze particle number density and surface deposition results, and estimate the expected flux of ice grains on a spacecraft. Due to Europa's high escape speed, observing an active plume will require low-altitude flybys, preferably at altitudes of 5-100 km. At higher altitudes a plume may escape detection. Our simulations provide an extensive library documenting the possible structure of Europa dust plumes, which can be quickly refined as more data on Europa dust plumes are collected.

Photographer : JPL Range : 5.9 million kilometers (3.66 million miles) Europa is Jupiter's 2nd

NASA Technical Reports Server (NTRS)

1979-01-01

Photographer : JPL Range : 5.9 million kilometers (3.66 million miles) Europa is Jupiter's 2nd Galilean satellite from the planet. Photo taken early morning and through a violet filter. Faint swirls and Linear Patterns show in the equarorial region(which is darker than the poles). The hemisphere shown always faces Jupiter. North is up. Europa is the brightest of the Galilian satellites but shows low contrast on this hemisphere. Density and size is similar to Earth's Moon. Indications of water ice or ground water on surface is shown

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

Europa's Interaction with Jupiter's Magnetosphere: Galileo Plasma Observations Revisited.

NASA Astrophysics Data System (ADS)

Heuer, S. V.; Rymer, A. M.; Westlake, J. H.; Paterson, W. R.; Collinson, G.

2017-12-01

The Galileo spacecraft was active at Jupiter from December 1995 to September 2003, carrying the Galileo Plasma Science Instrument (PLS), an electrostatic analyzer with three spherical-segment plates which directed energy selected particles into one of seven electron sensors or seven ion channels with field-of-views which combined to cover 80% of the 4pi-sr unit sphere (Frank et al., 1992). While Galileo accomplished most of its primary scientific objectives, the mission did not reach its full potential due to a failed high-gain antenna deployment which severely limited the available bandwidth for data transmission. Consequently, the PLS was limited by bandwidth availability, and only collected data with high temporal and energy resolution for short periods of time (e.g. review by Bagenal et al., 2016). The electron sensors were also negatively affected by the gaseous environment around Jupiter, which is suspected to have deposited a layer of contaminants on the detectors, raising the threshold energy required to pass through the aperture and effectively preventing the measurement of electrons below 1keV (Frank et al., 2002). As a result, data from the PLS is challenging to process and interpret. Ion plasma moments have been computed (and published on the PDS) in the magnetosphere, but moon flybys were excluded (Bagenal et al., 2016). In anticipation of future in-situ exploration of the Europa plasma environment, we present analysis of full-resolution plasma data acquired by the PLS during the nine Europa flybys and compare our results with existing data in order to further inform designs currently being worked for the Europa Clipper and JUICE missions.

Europa: Sea Salts or Battery Acid

NASA Image and Video Library

2000-04-19

This composite image of the Jupiter-facing hemisphere of Europa was obtained on Nov. 25, 1999 by NASA Galileo spacecraft. Blue areas show cleanest, brightest icy surfaces, while the red areas have the highest concentrations of darker, non-ice materials.

Europa Tide Movie

NASA Technical Reports Server (NTRS)

2007-01-01

[figure removed for brevity, see original site] Click on the image for Europa Tide Movie

In this movie Europa is seen in a cutaway view through two cycles of its 3.5 day orbit about the giant planet Jupiter. Like Earth, Europa is thought to have an iron core, a rocky mantle and a surface ocean of salty water. Unlike on Earth, however, this ocean is deep enough to cover the whole moon, and being far from the sun, the ocean surface is globally frozen over. Europa's orbit is eccentric, which means as it travels around Jupiter, large tides, raised by Jupiter, rise and fall. Jupiter's position relative to Europa is also seen to librate, or wobble, with the same period. This tidal kneading causes frictional heating within Europa, much in the same way a paper clip bent back and forth can get hot to the touch, as illustrated by the red glow in the interior of Europa's rocky mantle and in the lower, warmer part of its ice shell. This tidal heating is what keeps Europa's ocean liquid and could prove critical to the survival of simple organisms within the ocean, if they exist.

Europa's Active Surface

NASA Technical Reports Server (NTRS)

1996-01-01

A newly discovered impact crater can be seen just right of the center of this image of Jupiter's moon Europa returned by NASA's Galileo spacecraft camera. The crater is about 30 kilometers (18.5 miles) in diameter. The impact excavated into Europa's icy crust, throwing debris (seen as whitish material) across the surrounding terrain. Also visible is a dark band, named Belus Linea, extending east-west across the image. This type of feature, which scientists call a 'triple band,' is characterized by a bright stripe down the middle. The outer margins of this and other triple bands are diffuse, suggesting that the dark material was put there as a result of possible geyser-like activity which shot gas and rocky debris from Europa's interior. The curving 'X' pattern seen in the lower left corner of the image appears to represent fracturing of the icy crust and infilling by slush which froze in place. The crater is centered at about 2 degrees north latitude by 239 degrees west longitude. The image was taken from a distance of 156,000 kilometers (about 96,300 miles) on June 27, 1996, during Galileo's first orbit around Jupiter. The area shown is 860 by 700 kilometers (530 by 430 miles), or about the size of Oregon and Washington combined. The Galileo mission is managed by NASA's Jet Propulsion Laboratory.

NASA Hosts Live Science Chat about Europa Findings

NASA Image and Video Library

2018-05-14

NASA hosted a Science Chat May 14 to discuss the latest analysis of Jupiter’s moon Europa and its status as one of the most promising places in the solar system to search for life. The event aired live on NASA Television, Facebook Live, Twitch TV, Ustream, YouTube, Twitter/Periscope and the agency's website. Europa has long been a high priority for exploration because beneath its icy crust lies a salty, liquid water ocean. NASA’s Europa Clipper, targeted to launch in 2022, will be equipped with the instruments necessary to determine whether Europa possesses the ingredients necessary to support life as we know it.

Europa Rising

NASA Technical Reports Server (NTRS)

2007-01-01

New Horizons took this image of the icy moon Europa rising above Jupiter's cloud tops with its Long Range Reconnaissance Imager (LORRI) at 11:48 Universal Time on February 28, 2007, six hours after the spacecraft's closest approach to Jupiter.

The picture was one of a handful of the Jupiter system that New Horizons took primarily for artistic, rather than scientific, value. This particular scene was suggested by space enthusiast Richard Hendricks of Austin, Texas, in response to an Internet request by New Horizons scientists for evocative, artistic imaging opportunities at Jupiter.

The spacecraft was 2.3 million kilometers (1.4 million miles) from Jupiter and 3 million kilometers (1.8 million miles) from Europa when the picture was taken. Europa's diameter is 3,120 kilometers (1,939 miles). The image is centered on Europa coordinates 5 degrees south, 6 degrees west. In keeping with its artistic intent - and to provide a more dramatic perspective - the image has been rotated so south is at the top.

ScienceCast 38: The Great Lakes of Europa

NASA Image and Video Library

2011-11-23

Scientists studying data from NASA's Galileo probe have discovered what appears to be a body of liquid water the volume of the North American Great Lakes locked inside the icy shell of Jupiter's moon Europa.

Models, figures, and gravitational moments of Jupiter's satellites Io and Europa

NASA Astrophysics Data System (ADS)

Zharkov, V. N.; Karamurzov, B. S.

2006-07-01

Two types of trial three-layer models have been constructed for the satellites Io and Europa. In the models of the first type (Io1 and E1), the cores are assumed to consist of eutectic Fe-FeS melt with the densities ρ 1 = 5.15 g cm-3 (Io1) and 5.2 g cm-3 (E1). In the models of the second type (Io3 and E3), the cores consist of FeS with an admixture of nickel and have the density ρ 1 = 4.6 g cm-3. The approach used here differs from that used previously both in chosen model chemical composition of these satellites and in boundary conditions imposed on the models. The most important question to be answered by modeling the internal structure of the Galilean satellites is that of the condensate composition at the formation epoch of Jupiter's system. Jupiter's core and the Galilean satellites were formed from the condensate. Ganymede and Callisto were formed fairly far from Jupiter in zones with temperatures below the water condensation temperature, water was entirely incorporated into their bodies, and their modeling showed the mass ratio of the icy (I) component to the rock (R) component in them to be I/R ˜ 1. The R composition must be clarified by modeling Io and Europa. The models of the second type (Io3 and E3), in which the satellite cores consist of FeS, yield 25.2 (Io3) and 22.8 (E3) for the core masses (in weight %). In discussing the R composition, we note that, theoretically, the material of which the FeS+Ni core can consist in the R accounts for ˜25.4% of the satellite mass. In this case, such an important parameter as the mantle silicate iron saturation is Fe# = 0.265. The Io3 and E3 models agree well with this theoretical prediction. The models of the first and second types differ markedly in core radius; thus, in principle, the R composition in the formation zone of Jupiter's system can be clarified by geophysical studies. Another problem studied here is that of the error made in modeling Io and Europa using the Radau-Darvin formula when passing from

A Pragmatic Path to Investigating Europa's Habitability

NASA Technical Reports Server (NTRS)

Pappalardo; Bengenal; Bar; Bills; Blankenship; Connerney; Kurth; McGrath; Moore; Prockter;

Multi-Body Capture to Low-altitude Circular Orbits at Europa

NASA Technical Reports Server (NTRS)

Grebow, Daniel J.; Petropoulos, Anastassios E.; Finlayson, Paul A.

2011-01-01

For capture to a 200-km circular orbit around Europa, millions of different points along the orbit are simulated in the Jupiter-Europa Restricted 3-Body Problem. The transfers exist as members of families of trajectories, where certain families consistently outperform the others. The trajectories are not sensitive to changes in inclination for the final circular orbit. The top performing trajectories appear to follow the invariant manifolds of L2 Lyapunov orbits for capture into a retrograde orbit, and in some cases saving up to 40% of the from the patched 2-body problem. Transfers are attached to the current nominal mission for NASA's Jupiter-Europa Orbiter, where the total cost is roughly 100 m/s less than the baseline mission.

Early Formulation Model-centric Engineering on NASA's Europa Mission Concept Study

NASA Technical Reports Server (NTRS)

Bayer, Todd; Chung, Seung; Cole, Bjorn; Cooke, Brian; Dekens, Frank; Delp, Chris; Gontijo, Ivair; Lewis, Kari; Moshir, Mehrdad; Rasmussen, Robert;

Family Portrait of Jupiter Great Red Spot and the Galilean Satellites

NASA Image and Video Library

1997-11-18

This "family portrait," a composite of the Jovian system, includes the edge of Jupiter with its Great Red Spot, and Jupiter's four largest moons, known as the Galilean satellites. From top to bottom, the moons shown are Io, Europa, Ganymede and Callisto. The Great Red Spot, a storm in Jupiter's atmosphere, is at least 300 years old. Winds blow counterclockwise around the Great Red Spot at about 400 kilometers per hour (250 miles per hour). The storm is larger than one Earth diameter from north to south, and more than two Earth diameters from east to west. In this oblique view, the Great Red Spot appears longer in the north-south direction. Europa, the smallest of the four moons, is about the size of Earth's moon, while Ganymede is the largest moon in the solar system. North is at the top of this composite picture in which the massive planet and its largest satellites have all been scaled to a common factor of 15 kilometers (9 miles) per picture element. The Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft obtained the Jupiter, Io and Ganymede images in June 1996, while the Europa images were obtained in September 1996. Because Galileo focuses on high resolution imaging of regional areas on Callisto rather than global coverage, the portrait of Callisto is from the 1979 flyby of NASA's Voyager spacecraft. http://photojournal.jpl.nasa.gov/catalog/PIA00600

Plasma IMS Composition Measurements for Europa, Ganymede, and the Jovian System

NASA Technical Reports Server (NTRS)

Sittler, E. C., Jr.; Cooper, J. F.; Hartle, R. E.; Paterson, W. R.; Christian, E. R.; Lipatov, A. S.; Mahaffy, P R.; Paschalidis, N.; Sarantos, M.; Coplan, M. A.;

Plasma IMS Composition Measurements for Europa, Ganymede, and the Jovian Systems

NASA Technical Reports Server (NTRS)

Sittler, E.; Cooper, J.; Hartle, R.; Paterson ,W.; Christian, E.; Mahaffy, P.; Paschalidis, N.; Lipatov, A.; Sarantos, M.; Coplan, M.;

Europa Stunning Surface

NASA Image and Video Library

2014-11-21

The puzzling, fascinating surface of Jupiter icy moon Europa looms large in this newly-reprocessed [sic] color view, made from images taken by NASA Galileo spacecraft in the late 1990s. This is the color view of Europa from Galileo that shows the largest portion of the moon's surface at the highest resolution. The view was previously released as a mosaic with lower resolution and strongly enhanced color (see PIA02590). To create this new version, the images were assembled into a realistic color view of the surface that approximates how Europa would appear to the human eye. The scene shows the stunning diversity of Europa's surface geology. Long, linear cracks and ridges crisscross the surface, interrupted by regions of disrupted terrain where the surface ice crust has been broken up and re-frozen into new patterns. Color variations across the surface are associated with differences in geologic feature type and location. For example, areas that appear blue or white contain relatively pure water ice, while reddish and brownish areas include non-ice components in higher concentrations. The polar regions, visible at the left and right of this view, are noticeably bluer than the more equatorial latitudes, which look more white. This color variation is thought to be due to differences in ice grain size in the two locations. Images taken through near-infrared, green and violet filters have been combined to produce this view. The images have been corrected for light scattered outside of the image, to provide a color correction that is calibrated by wavelength. Gaps in the images have been filled with simulated color based on the color of nearby surface areas with similar terrain types. This global color view consists of images acquired by the Galileo Solid-State Imaging (SSI) experiment on the spacecraft's first and fourteenth orbits through the Jupiter system, in 1995 and 1998, respectively. Image scale is 1 mile (1.6 kilometers) per pixel. North on Europa is at right

Europa Scene: Plume, Galileo, Magnetic Field (Artist's Concept)

NASA Image and Video Library

2018-05-14

Artist's illustration of Jupiter and Europa (in the foreground) with the Galileo spacecraft after its pass through a plume erupting from Europa's surface. A new computer simulation gives us an idea of how the magnetic field interacted with a plume. The magnetic field lines (depicted in blue) show how the plume interacts with the ambient flow of Jovian plasma. The red colors on the lines show more dense areas of plasma. https://photojournal.jpl.nasa.gov/catalog/PIA21922

Photographer : JPL Range : 5.9 million kilometers (3.66 million miles) Europa is Jupiter's 2nd

NASA Technical Reports Server (NTRS)

1979-01-01

Photographer : JPL Range : 5.9 million kilometers (3.66 million miles) Europa is Jupiter's 2nd Galilean satellites from the planet and the brightest. Photo taken early morning through violet filter. Faint swirls and linear patterns show in the equatorial region (which shows darker than the poles). This hemisphere always faces Jupiter. North is up. Density and size comparable to Earth's Moon and seems to show water ice or ground water on its surface.

Europa Explorer: A Mission to Explore Europa and Investigate Its Habitability

NASA Astrophysics Data System (ADS)

Pappalardo, Robert T.; Clark, K.; Greeley, R.; Abelson, R.; Bills, B.; Blankenship, D.; Jorgenson, E.; Kahn, P.; Khurana, K.; Kirby, K.; Klaasen, K.; Lock, R.; Man, G.; McCord, T.; Moore, W.; Paranicas, C.; Prockter, L.; Rasmussen, R.; Sogin, M.

2007-10-01

Europa is the astrobiological archetype for icy satellite habitability, with a warm, salty, water ocean with plausible chemical energy sources. It is also a geophysical wonderland of interrelated ice shell processes that are intimately related to the ocean and tides, and of complex interactions among its interior, surface, atmosphere, and particles and fields environments. The Europa Explorer is a mature orbiter mission concept to explore Europa and investigate its habitability, fulfilling objectives laid out by the National Research Council's Planetary Science Decadal Survey. The mission examines Europa's ocean, ice shell, chemistry, geology, external environment (fields, particles, and atmosphere), and neighborhood (the Jupiter system). Science questions for Europa are well-honed, yet we anticipate being surprised by discoveries. Europa Explorer would nominally launch in June 2015, on a Venus-Earth-Earth Gravity Assist trajectory with a 6 year flight time to the Jupiter system. It would orbit Jupiter for 2 years using gravity assists of the icy Galilean satellites to lower its energy, providing the opportunity for significant Jupiter system science. It would then enter Europa orbit at an altitude of 100-200 km, where it would perform science investigations for 1 year. A campaign-based operations scenario has been developed which permits return of 5.4 Tbits of science data beginning in July 2021, and emphasizing the highest priority Europa science objectives early in the orbital phase of the mission. The baseline mission concept includes 11 instruments that address high-priority investigations while providing the flexibility to respond to discoveries. The radiation design approach has been independently reviewed and validated, and a statistical lifetime prediction method has been developed. Past technology investments have reduced mission risk, making the Europa Explorer mission ready to move forward in order to address the high-priority astrobiological and

Highest Resolution Image of Europa

NASA Technical Reports Server (NTRS)

1998-01-01

During its twelfth orbit around Jupiter, on Dec. 16, 1997, NASA's Galileo spacecraft made its closest pass of Jupiter's icy moon Europa, soaring 200 kilometers (124 miles) kilometers above the icy surface. This image was taken near the closest approach point, at a range of 560 kilometers (335 miles) and is the highest resolution picture of Europa that will be obtained by Galileo. The image was taken at a highly oblique angle, providing a vantage point similar to that of someone looking out an airplane window. The features at the bottom of the image are much closer to the viewer than those at the top of the image. Many bright ridges are seen in the picture, with dark material in the low-lying valleys. In the center of the image, the regular ridges and valleys give way to a darker region of jumbled hills, which may be one of the many dark pits observed on the surface of Europa. Smaller dark, circular features seen here are probably impact craters.

North is to the right of the picture, and the sun illuminates the surface from that direction. This image, centered at approximately 13 degrees south latitude and 235 degrees west longitude, is approximately 1.8 kilometers (1 mile) wide. The resolution is 6 meters (19 feet) per picture element. This image was taken on December 16, 1997 by the solid state imaging system camera on NASA's Galileo spacecraft.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

Study of Power Options for Jupiter and Outer Planet Missions

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Fincannon, James

2015-01-01

Power for missions to Jupiter and beyond presents a challenging goal for photovoltaic power systems, but NASA missions including Juno and the upcoming Europa Clipper mission have shown that it is possible to operate solar arrays at Jupiter. This work analyzes photovoltaic technologies for use in Jupiter and outer planet missions, including both conventional arrays, as well as analyzing the advantages of advanced solar cells, concentrator arrays, and thin film technologies. Index Terms - space exploration, spacecraft solar arrays, solar electric propulsion, photovoltaic cells, concentrator, Fresnel lens, Jupiter missions, outer planets.

A new concept for the exploration of Europa.

PubMed

Rampelotto, Pabulo Henrique

2012-06-01

The Europa Jupiter System Mission (EJSM) is the major Outer Planet Flagship Mission in preparation by NASA. Although well designed, the current EJSM concept may present problematic issues as a Flagship Mission for a long-term exploration program that will occur over the course of decades. For this reason, the present work reviews the current EJSM concept and presents a new strategy for the exploration of Europa. In this concept, the EJSM is reorganized to comprise three independent missions focused on Europa. The missions are split according to scientific goals, which together will give a complete understanding of the potential habitability of Europa, including in situ life's signal measurements. With this alternative strategy, a complete exploration of Europa would be possible in the next decades, even within a politically and economically constrained environment.

Scientific Investigation of the Jovian System: the Jupiter System Observer Mission Concept

NASA Astrophysics Data System (ADS)

Spilker, Thomas R.; Senske, D. A.; Prockter, L.; Kwok, J. H.; Tan-Wang, G. H.; SDT, JSO

2007-10-01

NASA's Science Mission Directorate (SMD), in efforts to start an outer solar system flagship mission in the near future, commissioned studies of mission concepts for four high-priority outer solar system destinations: Europa, the Jovian system, Titan, and Enceladus. Our team has identified and evaluated science and mission architectures to investigate major elements of the Jovian system: Jupiter, the Galilean moons, rings, and magnetosphere, and their interactions. SMD dubbed the mission concept the "Jupiter System Observer (JSO)." At abstract submission this JPL-led study is nearly complete, with final report submission in August 2007. SMD intends to select a subset of these four concepts for additional detailed study, leading to a potential flagship mission new start. A rich set of science objectives that JSO can address quite well have been identified. The highly capable science payload (including 50-cm optic), an extensive tour with multiple close flybys of Io, Europa, Ganymede and Callisto, and a significant time in orbit at Ganymede, addresses a large set of Solar System Exploration Decadal Survey (2003) and NASA Solar System Exploration Roadmap (2006) high-priority objectives. With the engineering team, the Science Definition Team evaluated a suite of mission architectures and the science they enable to arrive at two architectures that provide the best science for their estimated mission costs. This paper discusses the science objectives and operational capabilities and considerations for these mission concepts. This work was performed at JPL, APL, and other institutions under contract to NASA.

The Jupiter System Observer Mission Concept: Scientific Investigation of the Jovian System

NASA Astrophysics Data System (ADS)

Spilker, T. R.; Senske, D. A.; Prockter, L.; Kwok, J. H.; Tan-Wang, G. H.; Sdt, J.

2007-12-01

NASA's Science Mission Directorate (SMD), in efforts to start an outer solar system flagship mission in the near future, commissioned studies of mission concepts for four high-priority outer solar system destinations: Europa, the Jovian system, Titan, and Enceladus. Our team has identified and evaluated science and mission architectures to investigate major elements of the Jovian system: Jupiter, the Galilean moons, rings, and magnetosphere, and their interactions. SMD dubbed the mission concept the "Jupiter System Observer (JSO)." This JPL-led study's final report is now complete and was submitted in August 2007. SMD intends to select a subset of these four concepts for additional detailed study, leading to a potential flagship mission new start. The study's NASA-appointed, multi-institutional Science Definition Team (SDT) identified a rich set of science objectives that JSO can address quite well. The highly capable science payload (including ~50-cm optics), an extensive tour with multiple close flybys of Io, Europa, Ganymede and Callisto, and a significant time in orbit at Ganymede, addresses a large set of Solar System Exploration Decadal Survey (2003) and NASA Solar System Exploration Roadmap (2006) high-priority objectives. With the engineering team, the SDT evaluated a suite of mission architectures and the science they enable to arrive at two architectures that provide the best science for their estimated mission costs. This paper discusses the science objectives and operational capabilities and considerations for these mission concepts, and some options available for emphasizing specific science objectives. This work was performed at JPL, APL, and other institutions under contract to NASA.

System concepts and enabling technologies for an ESA low-cost mission to Jupiter / Europa

NASA Astrophysics Data System (ADS)

Renard, P.; Koeck, C.; Kemble, Steve; Atzei, Alessandro; Falkner, Peter

2004-11-01

The European Space Agency is currently studying the Jovian Minisat Explorer (JME), as part of its Technology Reference Studies (TRS), used for its development plan of technologies enabling future scientific missions. The JME focuses on the exploration of the Jovian system and particularly of Europa. The Jupiter Minisat Orbiter (JMO) study concerns the first mission phase of JME that counts up to three missions using pairs of minisats. The scientific objectives are the investigation of Europa's global topography, the composition of its (sub)surface and the demonstration of existence of a subsurface ocean below its icy crust. The present paper describes the candidate JMO system concept, based on a Europa Orbiter (JEO) supported by a communications relay satellite (JRS), and its associated technology development plan. It summarizes an analysis performed in 2004 jointly by ESA and the EADS-Astrium Company in the frame of an industrial technical assistance to ESA.

Natural and False Color Views of Europa

NASA Image and Video Library

1997-11-18

This image, taken on September 7, 1996 by NASA Galileo orbiter, shows two views of the trailing hemisphere of Jupiter ice-covered satellite, Europa. The left image shows the approximate natural color appearance of Europa. The image on the right is a false-color composite version combining violet, green and infrared images to enhance color differences in the predominantly water-ice crust of Europa. Dark brown areas represent rocky material derived from the interior, implanted by impact, or from a combination of interior and exterior sources. Bright plains in the polar areas (top and bottom) are shown in tones of blue to distinguish possibly coarse-grained ice (dark blue) from fine-grained ice (light blue). Long, dark lines are fractures in the crust, some of which are more than 3,000 kilometers (1,850 miles) long. The bright feature containing a central dark spot in the lower third of the image is a young impact crater some 50 kilometers (31 miles) in diameter. This crater has been provisionally named "Pwyll" for the Celtic god of the underworld. Europa is about 3,160 kilometers (1,950 miles) in diameter, or about the size of Earth's moon. This image was taken on September 7, 1996, at a range of 677,000 kilometers (417,900 miles) by the solid state imaging television camera onboard the Galileo spacecraft during its second orbit around Jupiter. The image was processed by Deutsche Forschungsanstalt fuer Luftund Raumfahrt e.V., Berlin, Germany. http://photojournal.jpl.nasa.gov/catalog/PIA00502

Natural and False Color Views of Europa

NASA Technical Reports Server (NTRS)

1996-01-01

This image shows two views of the trailing hemisphere of Jupiter's ice-covered satellite, Europa. The left image shows the approximate natural color appearance of Europa. The image on the right is a false-color composite version combining violet, green and infrared images to enhance color differences in the predominantly water-ice crust of Europa. Dark brown areas represent rocky material derived from the interior, implanted by impact, or from a combination of interior and exterior sources. Bright plains in the polar areas (top and bottom) are shown in tones of blue to distinguish possibly coarse-grained ice (dark blue) from fine-grained ice (light blue). Long, dark lines are fractures in the crust, some of which are more than 3,000 kilometers (1,850 miles) long. The bright feature containing a central dark spot in the lower third of the image is a young impact crater some 50 kilometers (31 miles) in diameter. This crater has been provisionally named 'Pwyll' for the Celtic god of the underworld.

Europa is about 3,160 kilometers (1,950 miles) in diameter, or about the size of Earth's moon. This image was taken on September 7, 1996, at a range of 677,000 kilometers (417,900 miles) by the solid state imaging television camera onboard the Galileo spacecraft during its second orbit around Jupiter. The image was processed by Deutsche Forschungsanstalt fuer Luftund Raumfahrt e.V., Berlin, Germany.

The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the Galileo mission home page on the World Wide Web at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http://www.jpl.nasa.gov/galileo/sepo

Tidal reorientation and the fracturing of Jupiter's moon Europa

USGS Publications Warehouse

McEwen, A.S.

1986-01-01

The most striking characteristic of Europa is the network of long linear albedo markings over the surface, suggestive of global-scale tectonic processes. Various explanations for the fractures have been proposed: Freezing and expansion of an early liquid water ocean1, planetary expansion due to dehydration of hydrated silicates2, localization by weak points in the crust generated by impacts3, and a combination of stresses due to planetary volume change and tidal distortions from orbital recession and orbital eccentricity4,5. Calculations by Yoder6 and Greenberg and Weidenschilling7 have shown that Europa may rotate slightly more rapidly than the synchronous rate, with a rotation period (reorientation through 360??) ranging from 20 to >103 yr if a liquid mantle is present, or up to 1010 yr if the satellite is essentially solid7. Helfen-stein and Parmentier8 modelled the stresses due to nonsynchronous rotation, and concluded that this could explain the long fractures in part of the anti-jovian hemisphere. In this note, I present a global map of lineaments with long arc lengths (>20?? or 550 km), and compare the lineament orientations to the tensile stress trajectories due to tidal distortions (changes in the lengths of three principal semiaxes) and to nonsynchronous rotation (longitudinal reorientation of two of the principal semiaxes). An excellent orthogonal fit to the lineaments is achieved by the stresses due to nonsynchronous rotation with the axis radial to Jupiter located 25?? east of its present position. This fit suggests that nonsynchronous rotation occurred at some time in Europa's history. ?? 1986 Nature Publishing Group.

Dome shaped features on Europa's surface

NASA Technical Reports Server (NTRS)

1997-01-01

The Solid State Imaging system aboard the spacecraft Galileo took this image of the surface of Europa on February 20, 1997 during its sixth orbit around Jupiter. The image is located near 16 North, 268 West; illumination is from the lower-right. The area covered is approximately 48 miles (80 kilometers) by 56 miles (95 kilometers) across. North is toward the top of the image.

This image reveals that the icy surface of Europa has been disrupted by ridges and faults numerous times during its past. These ridges have themselves been disrupted by the localized formation of domes and other features that may be indicative of thermal upwelling of water from beneath the crust. These features provide strong evidence for the presence of subsurface liquid during Europa's recent past.

The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

Europa Ice Floes

NASA Technical Reports Server (NTRS)

1997-01-01

Jupiter's moon Europa, as seen in this image taken June 27, 1996 by NASA's Galileo spacecraft, displays features in some areas resembling ice floes seen in Earth's polar seas. Europa, about the size of Earth's moon, has an icy crust that has been severely fractured, as indicated by the dark linear, curved, and wedged-shaped bands seen here. These fractures have broken the crust into plates as large as 30 kilometers (18.5 miles) across. Areas between the plates are filled with material that was probably icy slush contaminated with rocky debris. Some individual plates were separated and rotated into new positions. Europa's density indicates that it has a shell of water ice thicker than 100 kilometers (about 60 miles), parts of which could be liquid. Currently, water ice could extend from the surface down to the rocky interior, but the features seen in this image suggest that motion of the disrupted icy plates was lubricated by soft ice or liquid water below the surface at the time of disruption. This image covers part of the equatorial zone of Europa and was taken from a distance of 156,000 kilometers (about 96,300 miles) by the Solid-state Imaging Subsystem on the Galileo spacecraft. North is to the right and the sun is nearly directly overhead. The area shown is about 510 by 989 kilometers (310-by-600 miles), and the smallest visible feature is about 1.6 kilometers (1 mile) across.

The Jet Propulsion Laboratory manages the Galileo mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at http:// www.jpl.nasa.gov/galileo/sepo.

Plasma IMS Composition Measurements for Europa and the Other Galilean Moons

NASA Astrophysics Data System (ADS)

Sittler, Edward; Cooper, John; Hartle, Richard; Lipatov, Alexander; Mahaffy, Paul; Paterson, William; Pachalidis, Nick; Coplan, Mike; Cassidy, Tim

2010-05-01

NASA and ESA are planning the joint Europa Jupiter System Mission (EJSM) to the Jupiter system with specific emphasis to Europa and Ganymede, respectively. The Japanese Space Agency is also planning an orbiter mission to explore Jupiter's magnetosphere and the Galilean satellites. For NASA's Jupiter Europa Orbiter (JEO) we are developing the 3D Ion Mass Spectrometer (IMS) with two main goals which can also be applied to the other Galilean moons, 1) measure the plasma interaction between Europa and Jupiter's magnetosphere and 2) infer the 4? surface composition to trace elemental [1] and significant isotopic levels. The first goal supports the magnetometer (MAG) measurements, primarily directed at detection of Europa's sub-surface ocean, while the second gives information about transfer of material between the Galilean moons, and between the moon surfaces and subsurface layers putatively including oceans. The measurement of the interactions for all the Galilean moons can be used to trace the in situ ion measurements of pickup ions back to either Europa's or Ganymede's surface from the respectively orbiting spacecraft. The IMS instrument, being developed under NASA's Astrobiology Instrument Development Program, would maximally achieve plasma measurement requirements for JEO and EJSM while moving forward our knowledge of Jupiter system composition and source processes to far higher levels than previously envisaged. The composition of the global surfaces of Europa and Ganymede can be inferred from the measurement of ejected neutrals and pick-up ions using at minimum an in situ payload including MAG and IMS also fully capable of meeting Level 1 mission requirements for ocean detection and survey. Elemental and isotopic analysis of potentially extruded oceanic materials at the moon surfaces would further support the ocean objectives. These measurements should be made from a polar orbiting spacecraft about Europa or Ganymede at height ~ 100 km. The ejecta produced by

Family Portrait of Jupiter's Great Red Spot and the Galilean Satellites

NASA Technical Reports Server (NTRS)

1997-01-01

This 'family portrait,' a composite of the Jovian system, includes the edge of Jupiter with its Great Red Spot, and Jupiter's four largest moons, known as the Galilean satellites. From top to bottom, the moons shown are Io, Europa, Ganymede and Callisto.

The Great Red Spot, a storm in Jupiter's atmosphere, is at least 300 years old. Winds blow counterclockwise around the Great Red Spot at about 400 kilometers per hour (250 miles per hour). The storm is larger than one Earth diameter from north to south, and more than two Earth diameters from east to west. In this oblique view, the Great Red Spot appears longer in the north-south direction.

Europa, the smallest of the four moons, is about the size of Earth's moon, while Ganymede is the largest moon in the solar system. North is at the top of this composite picture in which the massive planet and its largest satellites have all been scaled to a common factor of 15 kilometers (9 miles) per picture element.

The Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft obtained the Jupiter, Io and Ganymede images in June 1996, while the Europa images were obtained in September 1996. Because Galileo focuses on high resolution imaging of regional areas on Callisto rather than global coverage, the portrait of Callisto is from the 1979 flyby of NASA's Voyager spacecraft.

Launched in October 1989, the spacecraft's mission is to conduct detailed studies of the giant planet, its largest moons and the Jovian magnetic environment. The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at: http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at: http:/ /www.jpl.nasa.gov/galileo/sepo.

Plasma IMS Composition Measurements for Europa and the Other Galilean Moons

NASA Technical Reports Server (NTRS)

Sittler, Edward; Cooper, John; Hartle, Richard; Lipatov, Alexander; Mahaffy, Paul; Paterson, William; Pachalidis, Nick; Coplan, Mike; Cassidy, Tim

2010-01-01

NASA and ESA are planning the joint Europa Jupiter System Mission (EJSM) to the Jupiter system with specific emphasis to Europa and Ganymede, respectively. The Japanese Space Agency is also planning an orbiter mission to explore Jupiter's magnetosphere and the Galilean satellites. For NASA's Jupiter Europa Orbiter (JEO) we are developing the 3D Ion Mass Spectrometer (IMS) with two main goals which can also be applied to the other Galilean moons, 1) measure the plasma interaction between Europa and Jupiter's magnetosphere and 2) infer the 4 pi surface composition to trace elemental and significant isotopic levels. The first goal supports the magnetometer (MAG) measurements, primarily directed at detection of Europa's sub-surface ocean, while the second gives information about transfer of material between the Galilean moons, and between the moon surfaces and subsurface layers putatively including oceans. The measurement of the interactions for all the Galilean moons can be used to trace the in situ ion measurements of pickup ions back to either Europa's or Ganymede's surface from the respectively orbiting spacecraft. The IMS instrument, being developed under NASA's Astrobiology Instrument Development Program, would maximally achieve plasma measurement requirements for JEO and EJSM while moving forward our knowledge of Jupiter system composition and source processes to far higher levels than previously envisaged. The composition of the global surfaces of Europa and Ganymede can be inferred from the measurement of ejected neutrals and pick-up ions using at minimum an in situ payload including MAG and IMS also fully capable of meeting Level 1 mission requirements for ocean detection and survey. Elemental and isotopic analysis of potentially extruded oceanic materials at the moon surfaces would further support the ocean objectives. These measurements should be made from a polar orbiting spacecraft about Europa or Ganymede at height 100 km. The ejecta produced by

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.

JUpiter ICy moons Explorer (JUICE): An ESA mission to orbit Ganymede and to characterise the Jupiter system

NASA Astrophysics Data System (ADS)

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

2013-04-01

Past exploration of Jupiter's diverse satellite system has forever changed our understanding of the unique environments to be found around gas giants, both in our solar system and beyond. The detailed investigation of three of Jupiter's Galilean satellites (Ganymede, Europa, and Callisto), which are believed to harbour subsurface water oceans, is central to elucidating the conditions for habitability of icy worlds in planetary systems in general. The study of the Jupiter system and the possible existence of habitable environments offer the best opportunity for understanding the origins and formation of the gas giants and their satellite systems. The JUpiter ICy moons Explorer (JUICE) mission, selected by ESA in May 2012 to be the first large mission within the Cosmic Vision Program 2015-2025, will perform detailed investigations of Jupiter and its system in all their inter-relations and complexity with particular emphasis on Ganymede as a planetary body and potential habitat. The investigations of the neighbouring moons, Europa and Callisto, will complete a comparative picture of the Galilean moons and their potential habitability. Here we describe the scientific motivation for this exciting new European-led exploration of the Jupiter system in the context of our current knowledge and future aspirations for exploration, and the paradigm it will bring in the study of giant (exo) planets in general.

Photographer : JPL Range : 4.2 million km. ( 2.6 million miles ) Jupiter's moon Europa, the size of

NASA Technical Reports Server (NTRS)

1979-01-01

Photographer : JPL Range : 4.2 million km. ( 2.6 million miles ) Jupiter's moon Europa, the size of earth's moon, is apparently covered by water ice, as indicated by ground spectrometers and its brightness. In this view, global scale dark sreaks discovered by Voyager 1 that criss-cross the the satelite are becoming visible. Bright rayed impact craters, which are abundant on Ganymede and Callisto, would be easily visible at this range, suggesting that Europa's surface is young and that the streaks are reflections of currently active internal dynamic processes.

Orbiter, Flyby and Lander Mission Concepts for Investigating Europa's Habitability

NASA Astrophysics Data System (ADS)

Prockter, L. M.

2012-04-01

Coauthors: R. T. Pappalardo (1), F. Bagenal (2), A. C. Barr (3), B. G. Bills (1), D. L. Blaney (1), D. D. Blankenship (4), W. Brinckerhoff (5), J. E. P. Connerney (5), K. Hand (1), T. Hoehler (6), W. Kurth (7), M. McGrath (8), M. Mellon (9), J. M. Moore (6), D. A. Senske (1), E. Shock (10), D. E. Smith (11), T. Gavin (1), G. Garner (1), T. Magner (12), B. C. Cooke (1), R. Crum (1), V. Mallder (12), L. Adams (12), K. Klaasen (1), G. W. Patterson (12), and S. D. Vance (1); 1: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA; 2: University of Colorado, Boulder, CO, USA; 3: Brown University, Providence, RI, USA; 4: University of Texas Institute for Geophysics, Austin, TX, USA; 5: NASA Goddard Space Flight Center, Greenbelt, MD, USA; 6: NASA Ames Research Center, Mountain View, CA, USA; 7: University of Iowa, Iowa City, IA, USA; 8: NASA Marshall Space Flight Center, Huntsville, AL, USA; 9: Southwest Research Institute, Boulder, CO, USA; 10: Arizona State University, Tempe, AZ, USA; 11: Massachusetts Institute of Technology, Cambridge, MA, USA; 12: Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA. Introduction: Assessment of Europa's habitability requires understanding whether the satellite possesses the three "ingredients" for life: water, chemistry, and energy. The National Research Council's Planetary Decadal Survey [1] placed an extremely high priority on Europa science but noted that the budget profile for the Jupiter Europa Orbiter (JEO) mission concept [2] is incompatible with NASA's projected planetary science budget. Thus, in April 2011, NASA enlisted a small Europa Science Definition Team (ESDT) to consider Europa mission options that might be more feasible over the next decade from a programmatic perspective. The ESDT has studied three Europa mission concepts: a Europa orbiter, a Europa multiple-flyby mission, and a Europa lander. These share an overarching goal: Explore Europa to investigate its habitability

The Europa Clipper mission concept

NASA Astrophysics Data System (ADS)

Pappalardo, Robert; Lopes, Rosaly

Jupiter's moon Europa may be a habitable world. Galileo spacecraft data suggest that an ocean most likely exists beneath Europa’s icy surface and that the “ingredients” necessary for life (liquid water, chemistry, and energy) could be present within this ocean today. Because of the potential for revolutionizing our understanding of life in the solar system, future exploration of Europa has been deemed an extremely high priority for planetary science. A NASA-appointed Science Definition Team (SDT), working closely with a technical team from the Jet Propulsion Laboratory (JPL) and the Applied Physics Laboratory (APL), recently considered options for a future strategic mission to Europa, with the stated science goal: Explore Europa to investigate its habitability. The group considered several mission options, which were fully technically developed, then costed and reviewed by technical review boards and planetary science community groups. There was strong convergence on a favored architecture consisting of a spacecraft in Jupiter orbit making many close flybys of Europa, concentrating on remote sensing to explore the moon. Innovative mission design would use gravitational perturbations of the spacecraft trajectory to permit flybys at a wide variety of latitudes and longitudes, enabling globally distributed regional coverage of the moon’s surface, with nominally 45 close flybys at altitudes from 25 to 100 km. We will present the science and reconnaissance goals and objectives, a mission design overview, and the notional spacecraft for this concept, which has become known as the Europa Clipper. The Europa Clipper concept provides a cost-efficient means to explore Europa and investigate its habitability, through understanding the satellite’s ice and ocean, composition, and geology. The set of investigations derived from these science objectives traces to a notional payload for science, consisting of: Ice Penetrating Radar (for sounding of ice-water interfaces

The search for active Europa plumes in Galileo plasma particle detector data: the E12 flyby

NASA Astrophysics Data System (ADS)

Huybrighs, H.; Roussos, E.; Krupp, N.; Fraenz, M.; Futaana, Y.; Barabash, S. V.; Glassmeier, K. H.

2017-12-01

Hubble Space Telescope observations of Europa's auroral emissions and transits in front of Jupiter suggest that recurring water vapour plumes originating from Europa's surface might exist. If conclusively proven, the discovery of these plumes would be significant, because Europa's potentially habitable ocean could be studied remotely by taking in-situ samples of these plumes from a flyby mission. The first opportunity to collect in-situ evidence of the plumes will not arise before the early 2030's when ESA's JUICE mission or NASA's Europa Clipper are set to arrive. However, it may be possible that NASA's Galileo mission has already encountered the plumes when it was active in the Jupiter system from 1995 to 2003. It has been suggested that the high plasma densities and anomalous magnetic fields measured during one of the Galileo flybys of Europa (flyby E12) could be connected to plume activity. In the context of the search for Europa plume signatures in Galileo particle data we present an overview of the in-situ plasma particle data obtained by the Galileo spacecraft during the E12 flyby. Focus is in particular on the data obtained with the plasma particle instruments PLS (low energy ions and electrons) and EPD (high energy ions and electrons). We search for signs of an extended exosphere/ionosphere that could be consistent with ongoing plume activity. The PLS data obtained during the E12 flyby show an extended interaction region between Europa and the plasma from Jupiter's magnetosphere, hinting at the existence of an extended ionosphere and exosphere. Furthermore we show how the EPD data are analyzed and modelled in order to evaluate whether a series of energetic ion depletions can be attributed to losses on the moon's surface or its neutral exosphere.

Power-Conversion Concept Designed for the Jupiter Icy Moons Orbiter

NASA Technical Reports Server (NTRS)

Mason, Lee S.

2004-01-01

The Jupiter Icy Moons Orbiter (JIMO) is a bold new mission being developed by NASA's Office of Space Science under Project Prometheus. JIMO is examining the potential of nuclear electric propulsion (NEP) technology to efficiently deliver scientific payloads to three of Jupiter's moons: Callisto, Ganymede, and Europa. A critical element of the NEP spacecraft is the space reactor power system (SRPS), consisting of the nuclear reactor, power conversion, heat rejection, and power management and distribution (PMAD).

Europa Explorer - An Exceptional Mission Using Existing Technology

NASA Technical Reports Server (NTRS)

Clark, Karla B.

2007-01-01

A mission to Europa has been identified as a high priority by the science community for several years. The difficulty of an orbital mission, primarily due to the propulsive requirements and Jupiter's trapped radiation, led to many studies which investigated various approaches to meeting the science goals. The Europa Orbiter Mission studied in the late 1990's only met the most fundamental science objectives. The science objectives have evolved with the discoveries from the Galileo mission. JPL studied one concept, Europa Explorer, for a Europa orbiting mission which could meet a much expanded set of science objectives. A study science group was formed to verify that the science objectives and goals were being adequately met by the resulting mission design concept. The Europa Explorer design emerged primarily from two key self-imposed constraints: 1) meet the full set of identified nonlander science objectives and 2) use only existing technology.

Europa's Broken Ice

NASA Technical Reports Server (NTRS)

1996-01-01

Jupiter's moon Europa, as seen in this image taken June 27, 1996 by NASA's Galileo spacecraft, displays features in some areas resembling ice floes seen in Earth's polar seas. Europa, about the size of Earth's moon, has an icy crust that has been severely fractured, as indicated by the dark linear, curved, and wedged-shaped bands seen here. These fractures have broken the crust into plates as large as 30 kilometers (18.5 miles) across. Areas between the plates are filled with material that was probably icy slush contaminated with rocky debris. Some individual plates were separated and rotated into new positions. Europa's density indicates that it has a shell of water ice as thick as 100 kilometers (about 60 miles), parts of which could be liquid. Currently, water ice could extend from the surface down to the rocky interior, but the features seen in this image suggest that motion of the disrupted icy plates was lubricated by soft ice or liquid water below the surface at the time of disruption. This image covers part of the equatorial zone of Europa and was taken from a distance of 156,000 kilometers (about 96,300 miles) by the solid-state imager camera on the Galileo spacecraft. North is to the right and the sun is nearly directly overhead. The area shown is about 360 by 770 kilometers (220-by-475 miles or about the size of Nebraska), and the smallest visible feature is about 1.6 kilometers (1 mile) across. The Jet Propulsion Laboratory manages the Galileo mission for NASA's Office of Space Science.

The Jupiter System Observer: Probing the Foundations of Planetary Systems

NASA Astrophysics Data System (ADS)

Senske, D.; Prockter, L.; Collins, G.; Cooper, J.; Hendrix, A.; Hibbitts, K.; Kivelson, M.; Orton, G.; Schubert, G.; Showman, A.; Turtle, E.; Williams, D.; Kwok, J.; Spilker, T.; Tan-Wang, G.

2007-12-01

Galileo's observations in the 1600's of the dynamic system of Jupiter and its moons launched a revolution in understanding the way planetary systems operate. Now, some 400 years later, the discovery of extra solar planetary systems with Jupiter-sized bodies has led to a similar revolution in thought regarding how these systems form and evolve. From the time of Galileo, the Jovian system has been viewed as a solar system in miniature, providing a laboratory to study, diverse and dynamic processes in a single place. The icy Galilean satellites provide a window into solar system history by preserving in their cratering records a chronology dating back nearly 4.5 By and extending to the present. The continuously erupting volcanoes of Io may provide insight into the era when magma oceans were common. The discovery of an internally generated magnetic field at Ganymede, one of only three terrestrial bodies to possess such a field, is a place to gain insight as to how dynamos work. The confirmation and characterization of icy satellite subsurface oceans impacts the way habitability is considered. Understanding the composition and volatile inventory of Jupiter can shed light into how planets accrete from the solar nebulae. Finally, like our sun, Jupiter influences its system through its extensive magnetic field. In early 2007, NASA's Science Mission Directorate formed four Science Definition Teams (SDTs) to formulate science goals and objectives in anticipation of the initiation of a flagship-class mission to the outer solar system (Europa, Jupiter system, Titan and Enceladus). The Jupiter System Observer (JSO) mission concept emphasizes overall Jupiter system science: 1) Jupiter and its atmosphere, 2) the geology and geophysics of the Galilean satellites (Io, Europa, Ganymede and Callisto), 3) the magnetosphere environment - both Jupiter's and Ganymede's&pand 4) interactions within the system. Focusing on the unique geology, presence of an internal magnetic field and

Flow-like Features On Europa

NASA Technical Reports Server (NTRS)

1997-01-01

This image shows features on Jupiter's moon Europa that may be 'flows' from ice volcanoes. It was taken by the Galileo spacecraft solid state imaging (CCD) system during its seventh orbit around Jupiter. North is to the top of the image. The sun illuminates the scene from the left, showing features with shapes similar to lava flows on Earth. Two such features can be seen in the northwest corner of the image. The southern feature appears to have flowed over a ridge along its western edge. Scientists use these types of relationships to determine which feature formed first. In this case, the ridge probably formed before the flow-like feature that covers it.

The image, centered at 22.6 degrees north latitude and 106.7 degrees west longitude, covers an area of 180 by 215 kilometers (112 by 134 miles). The smallest distinguishable features in the image are about 1.1 kilometers (0.7 miles) across. This image was obtained on April 28, 1997, when Galileo was 27,590 kilometers (16,830 miles) from Europa.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

Europa Global Views in Natural and Enhanced Colors

NASA Technical Reports Server (NTRS)

1998-01-01

This color composite view combines violet, green, and infrared images of Jupiter's intriguing moon, Europa, for a view of the moon in natural color (left) and in enhanced color designed to bring out subtle color differences in the surface (right). The bright white and bluish part of Europa's surface is composed mostly of water ice, with very few non-ice materials. In contrast, the brownish mottled regions on the right side of the image may be covered by hydrated salts and an unknown red component. The yellowish mottled terrain on the left side of the image is caused by some other unknown component. Long, dark lines are fractures in the crust, some of which are more than 3,000 kilometers (1,850 miles) long.

North is to the top of the picture and the sun fully illuminates the surface. Europa is about 3,160 kilometers (1,950 miles) in diameter, or about the size of Earth's moon. The finest details that can be discerned are 25 kilometers across. The images in this global view were taken in June 1997 at a range of 1.25 million kilometers by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft, during its ninth orbit of Jupiter.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

Science and Reconnaissance from the Europa Clipper Mission Concept: Exploring Europa's Habitability

NASA Astrophysics Data System (ADS)

Senske, D.; Pappalardo, R. T.; Prockter, L. M.; Paczkowski, B.; Vance, S.; Goldstein, B.; Magner, T. J.; Cooke, B.

2014-12-01

Europa is a prime candidate to search for a present-day habitable environment in our solar system. As such, NASA has engaged a Science Definition Team (SDT) to define a strategy to advance our scientific understanding of this icy world with the goal: Explore Europa to investigate its habitability. A mission architecture is defined where a spacecraft in Jupiter orbit would make many close flybys of Europa, concentrating on remote sensing to explore the moon. The spacecraft trajectory would permit ~45 flybys at a variety of latitudes and longitudes, enabling globally distributed regional coverage of Europa's surface. This concept is known as the Europa Clipper. The SDT recommended three science objectives for the Europa Clipper: Ice Shell and Ocean--Characterize the ice shell and any subsurface water, including their heterogeneity, ocean properties, and the nature of surface-ice-ocean exchange; Composition--Understand the habitability of Europa's ocean through composition and chemistry; Geology--Understand the formation of surface features, including sites of recent or current activity, and characterize high science interest localities. The SDT also considered implications of the recent HST detection of plumes at Europa. To feed forward to potential future exploration that could be enabled by a lander, it was deemed that the Clipper should provide the capability to perform reconnaissance. In consultation with NASA Headquarters, the SDT developed a reconnaissance goal: Characterize Scientifically Compelling Sites, and Hazards, for a Potential Future Landed Mission to Europa. This leads to two objectives: Site Safety--Assess the distribution of surface hazards, the load-bearing capacity of the surface, the structure of the subsurface, and the regolith thickness; Science Value--Assess the composition of surface materials, the geologic context of the surface, the potential for geological activity, the proximity of near surface water, and the potential for active

The GIRE2 Model and Its Application to the Europa Mission

NASA Technical Reports Server (NTRS)

De Soria-Santacruz Pich, Maria; Garrett, Henry B.; Evans, Robin W.; Jun, Insoo; Kim, Wousik; Paranicas, Chris

2016-01-01

We present an empirical model of Jupiter's electron radiation environment and its application to the design of the future NASA mission to Europa. The model is based on data from the Galileo spacecraft. Measurements of the high-energy, omni-directional electrons from the Energetic Particle Detector (EPD) and magnetic field from the Magnetometer (MAG) onboard Galileo are used for this purpose. Ten-minute averages of the EPD data are used to provide an omni-directional electron flux spectrum at 0.238, 0.416, 0.706, 1.5, 2.0, and 11.0 MeV. Additionally, data from the Geiger Tube Telescope onboard Pioneer 10 and 11 are used to calculate the flux of 31 MeV electrons. The Galileo Interim Radiation Electron model v.2 (GIRE2) combines these datasets with the original Divine model and synchrotron observations to estimate the trapped electron radiation environment. Unlike the original Divine model, which was based on flybys of the Voyager and Pioneer spacecraft, the new GIRE2 model covers about 7 years of data and more than 30 orbits around Jupiter from the Galileo spacecraft. The model represents a step forward in the study of the Jovian radiation environment and is a valuable tool to assist in the design of future missions to Jupiter. This paper gives an overview of GIRE2 and focuses on its application to the design of the future NASA mission to Europa. The spacecraft will orbit Jupiter and perform multiple flybys of the moon Europa, which is embedded in the middle of a very strong radiation environment. The radiation environment surrounding the moon as well as along the trajectory are described in the paper together with the implications of this environment on the design of a mission.

NASA's Hubble Takes Close-up Portrait of Jupiter

NASA Image and Video Library

2017-12-08

On April 3, 2017, as Jupiter made its nearest approach to Earth in a year, NASA’s Hubble Space Telescope viewed the solar system’s largest planet in all of its up-close glory. At a distance of 415 million miles (668 million kilometers) from Earth, Jupiter offered spectacular views of its colorful, roiling atmosphere, the legendary Great Red Spot, and it smaller companion at farther southern latitudes dubbed “Red Spot Jr.” Read more: go.nasa.gov/2o7tOhH Photo details: This dazzling Hubble Space Telescope photo of #Jupiter was taken when it was comparatively close to Earth, at a distance of 415 million miles. Hubble reveals the intricate, detailed beauty of Jupiter's clouds as arranged into bands of different latitudes, known as tropical regions. These bands are produced by air flowing in different directions at various latitudes. Lighter colored areas, called zones, are high-pressure where the atmosphere rises. Darker low-pressure regions where air falls are called belts. The planet's trademark, the Great Red Spot, is a long-lived storm roughly the diameter of Earth. Much smaller storms appear as white or brown-colored ovals. Such storms can last as little as a few hours or stretch on for centuries. Credit: NASA, ESA, and A. Simon (NASA Goddard) 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

Europa Tide Movie

NASA Image and Video Library

2007-12-13

In this image, Europa is seen in a cutaway view through two cycles of its 3.5 day orbit about the giant planet Jupiter. Like Earth, Europa is thought to have an iron core, a rocky mantle and a surface ocean of salty water. Animation available at the Photo

A Dark Spot on Europa

NASA Technical Reports Server (NTRS)

1998-01-01

This view taken by NASA's Galileo spacecraft of Jupiter's icy moon Europa focuses on a dark, smooth region whose center is the lowest area in this image. To the west (left), it is bounded by a cliff and terraces, which might have been formed by normal faulting. The slopes toward the east (right) leading into the dark spot are gentle.

Near the center of the dark area, it appears the dark materials have covered some of the bright terrain and ridges. This suggests that when the dark material was deposited, it may have been a fluid or an icy slush.

Only a few impact craters are visible, with some of them covered or flooded by dark material. Some appear in groups, which may indicate that they are secondary craters formed by debris excavated during a larger impact event. A potential source for these is the nearby crater Mannann`an.

North is to the top of the picture which is centered at 1 degree south latitude and 225 degrees west longitude. The images in this mosaic have been re-projected to 50 meters (55 yards) per picture element. They were obtained by the Solid State Imaging (SSI) system on March 29, 1998, during Galileo's fourteenth orbit of Jupiter, at ranges as close as 1940 kilometers (1,200 miles) from Europa.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

Europa: Initial Galileo Geological Observations

USGS Publications Warehouse

Greeley, R.; Sullivan, R.; Klemaszewski, J.; Homan, K.; Head, J. W.; Pappalardo, R.T.; Veverka, J.; Clark, B.E.; Johnson, T.V.; Klaasen, K.P.; Belton, M.; Moore, J.; Asphaug, E.; Carr, M.H.; Neukum, G.; Denk, T.; Chapman, C.R.; Pilcher, C.B.; Geissler, P.E.; Greenberg, R.; Tufts, R.

1998-01-01

Images of Europa from the Galileo spacecraft show a surface with a complex history involving tectonic deformation, impact cratering, and possible emplacement of ice-rich materials and perhaps liquids on the surface. Differences in impact crater distributions suggest that some areas have been resurfaced more recently than others; Europa could experience current cryovolcanic and tectonic activity. Global-scale patterns of tectonic features suggest deformation resulting from non-synchronous rotation of Europa around Jupiter. Some regions of the lithosphere have been fractured, with icy plates separated and rotated into new positions. The dimensions of these plates suggest that the depth to liquid or mobile ice was only a few kilometers at the time of disruption. Some surfaces have also been upwarped, possibly by diapirs, cryomagmatic intrusions, or convective upwelling. In some places, this deformation has led to the development of chaotic terrain in which surface material has collapsed and/or been eroded. ?? 1998 Academic Press.

The Europa Mission: Multiple Europa Flyby Trajectory Design Trades and Challenges

NASA Technical Reports Server (NTRS)

Lam, Try; Arrieta-Camacho, Juan J.; Buffington, Brent B.

2015-01-01

With potential sources of water, energy and other chemicals essential for life, Europa is a top candidate for finding current life in our Solar System outside of Earth. This paper describes the current trajectory design concept for a multiple Europa flyby mission and discusses several trajectory design challenges. The candidate reference trajectory utilizes multiple Europa flybys while around Jupiter to enable near global coverage of Europa while balancing science requirements, radiation dose, propellant usage, and flight time. Trajectory design trades and robustness are also discussed.

Oceans Beyond Earth on This Week @NASA – April 14, 2017

NASA Image and Video Library

2017-04-14

Two long-running NASA missions are providing new details about ocean bearing moons of Jupiter and Saturn – further heightening scientific interest in these and other “ocean worlds” in our solar system and beyond. The details – discussed during an April 13 NASA science briefing – include the announcement by the Cassini mission that a key ingredient for life has been found in the ocean on Saturn's moon Enceladus. Meanwhile, researchers using the Hubble Space Telescope observed a probable plume erupting from the surface of Jupiter's moon Europa, at the same location where Hubble saw evidence of a plume in 2014. Researchers say this could be circumstantial evidence of water erupting from the moon’s interior. Hubble's monitoring of plume activity on Europa and Cassini's long-term investigation of Enceladus are laying the groundwork for NASA's Europa Clipper mission, which is being planned for launch in the 2020s. Also, Expedition 50 Returns Home Safely, Next Space Station Crew at Launch Site, Student Launch Event, Groundbreaking for New Lab, and Yuri’s Night, First Space Shuttle Mission Celebrated!

Seismic detectability of meteorite impacts on Europa

NASA Astrophysics Data System (ADS)

Tsuji, Daisuke; Teanby, Nicholas

2016-04-01

Europa, the second of Jupiter's Galilean satellites, has an icy outer shell, beneath which there is probably liquid water in contact with a rocky core. Europa, may thus provide an example of a sub-surface habitable environment so is an attractive object for future lander missions. In fact, the Jupiter Icy Moon Explorer (JUICE) mission has been selected for the L1 launch slot of ESA's Cosmic Vision science programme with the aim of launching in 2022 to explore Jupiter and its potentially habitable icy moons. One of the best ways to probe icy moon interiors in any future mission will be with a seismic investigation. Previously, the Apollo seismic experiment, installed by astronauts, enhanced our knowledge of the lunar interior. For a recent mission, NASA's 2016 InSight Mars lander aims to obtain seismic data and will deploy a seismometer directly onto Mars' surface. Motivated by these works, in this study we show how many meteorite impacts will be detected using a single seismic station on Europa, which will be useful for planning the next generation of outer solar system missions. To this end, we derive: (1) the current small impact flux on Europa from Jupiter impact rate models; (2) a crater diameter versus impactor energy scaling relation for ice by merging previous experiments and simulations; (3) scaling relations for seismic signals as a function of distance from an impact site for a given crater size based on analogue explosive data obtained on Earth's icy surfaces. Finally, resultant amplitudes are compared to the noise level of a likely seismic instrument (based on the NASA InSight mission seismometers) and the number of detectable impacts are estimated. As a result, 0.5-3.0 local/regional small impacts (i.e., direct P-waves through the ice crust) are expected to be detected per year, while global-scale impact events (i.e., PKP-waves refracted through the mantle) are rare and unlikely to be detected by a short duration mission. We note that our results are

New horizons mapping of Europa and Ganymede.

PubMed

Grundy, W M; Buratti, B J; Cheng, A F; Emery, J P; Lunsford, A; McKinnon, W B; Moore, J M; Newman, S F; Olkin, C B; Reuter, D C; Schenk, P M; Spencer, J R; Stern, S A; Throop, H B; Weaver, H A

2007-10-12

The New Horizons spacecraft observed Jupiter's icy satellites Europa and Ganymede during its flyby in February and March 2007 at visible and infrared wavelengths. Infrared spectral images map H2O ice absorption and hydrated contaminants, bolstering the case for an exogenous source of Europa's "non-ice" surface material and filling large gaps in compositional maps of Ganymede's Jupiter-facing hemisphere. Visual wavelength images of Europa extend knowledge of its global pattern of arcuate troughs and show that its surface scatters light more isotropically than other icy satellites.

A Jupiter Ganymede Orbiter for the EJSM mission: the JGO assessment phase study by the Thales Alenia Space consortium

NASA Astrophysics Data System (ADS)

Poncy, Joel; Couzin, Patrice; Mercier, Manuel; Boschetti, Demis

2010-05-01

ESA and NASA have undertaken advanced studies of a common mission to Jupiter's system, EJSM (Europa Jupiter System Mission). This mission comprises two spacecrafts launched independently in 2020 and reaching the system in 2026. This is a one-in-a-generation opportunity for Europe to contribute significantly to the science of this part of the Solar System, and as such, all efforts shall subsequently be made to maximize the scientific return without jeopardizing the technical and programmatic feasibility of the mission. A sub-glacial ocean on Europa and potentially two others on Ganymede and Callisto, the monitoring of Io's volcanic activity, the upper atmosphere of Jupiter, its rings, its tens of irregular moons, the tides, the magnetic fields of Jupiter and Ganymede and the behaviour of the plasma, the list of science objectives is not only impressive but also generates enthusiasm in the mission. In this NASA-ESA joint mission, NASA will take charge of both Io and Europa with the Jupiter Europa Orbiter (JEO). Europe will get a fascinating share with the Jupiter Ganymede Orbiter (JGO), which will achieve the close study of the two largest and outermost Galilean moons Ganymede and Callisto and in addition, at-a-distance, the observation of the other targets mentioned above. ESA has awarded three industrial contracts for an assessment phase of JGO. As leader of one of the consortia, Thales Alenia Space is proud to present in this poster its achievements on this exciting mission. The requirements are discussed and the mission drivers identified. The main trades and the resulting architecture are recalled, along with the main selection drivers. The major system interrelated trades have covered the launcher and propulsion type, the number of regulated phases, the strategy for communications and science timeline, the need for HGA pointing, the sizing and configuration of the Solar Array, the accommodation of external appendages, the accommodation of the payload, the

Ridges on Europa

NASA Technical Reports Server (NTRS)

1997-01-01

This is the highest resolution picture ever taken of the Jupiter moon, Europa. The area shown is about 5.9 by 9.9 miles (9.6 by 16 kilometers) and the smallest visible feature is about the size of a football field. In this view, the ice-rich surface has been broken into a complex pattern by cross-cutting ridges and grooves resulting from tectonic processes. Sinuous rille-like features and knobby terrain could result from surface modifications of unknown origins. Small craters of possible impact origin range in size from less than 330 feet (100 meters) to about 1300 feet (400 meters) across are visible.

This image was taken by the solid state imaging television camera aboard the Galileo during its fourth orbit around Jupiter, at a distance of 2060 miles (3340 kilometers). The picture is centered at 325 degrees West, 5.83 degrees North. North is toward the top of this image, with the sun shining from the right.

The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the Galileo mission home page on the World Wide Web at http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

Towards a Global Unified Model of Europa's Tenuous Atmosphere

NASA Astrophysics Data System (ADS)

Plainaki, Christina; Cassidy, Tim A.; Shematovich, Valery I.; Milillo, Anna; Wurz, Peter; Vorburger, Audrey; Roth, Lorenz; Galli, André; Rubin, Martin; Blöcker, Aljona; Brandt, Pontus C.; Crary, Frank; Dandouras, Iannis; Jia, Xianzhe; Grassi, Davide; Hartogh, Paul; Lucchetti, Alice; McGrath, Melissa; Mangano, Valeria; Mura, Alessandro; Orsini, Stefano; Paranicas, Chris; Radioti, Aikaterini; Retherford, Kurt D.; Saur, Joachim; Teolis, Ben

2018-02-01

Despite the numerous modeling efforts of the past, our knowledge on the radiation-induced physical and chemical processes in Europa's tenuous atmosphere and on the exchange of material between the moon's surface and Jupiter's magnetosphere remains limited. In lack of an adequate number of in situ observations, the existence of a wide variety of models based on different scenarios and considerations has resulted in a fragmentary understanding of the interactions of the magnetospheric ion population with both the moon's icy surface and neutral gas envelope. Models show large discrepancy in the source and loss rates of the different constituents as well as in the determination of the spatial distribution of the atmosphere and its variation with time. The existence of several models based on very different approaches highlights the need of a detailed comparison among them with the final goal of developing a unified model of Europa's tenuous atmosphere. The availability to the science community of such a model could be of particular interest in view of the planning of the future mission observations (e.g., ESA's JUpiter ICy moons Explorer (JUICE) mission, and NASA's Europa Clipper mission). We review the existing models of Europa's tenuous atmosphere and discuss each of their derived characteristics of the neutral environment. We also discuss discrepancies among different models and the assumptions of the plasma environment in the vicinity of Europa. A summary of the existing observations of both the neutral and the plasma environments at Europa is also presented. The characteristics of a global unified model of the tenuous atmosphere are, then, discussed. Finally, we identify needed future experimental work in laboratories and propose some suitable observation strategies for upcoming missions.

Highest-resolution Europa Image & Mosaic from Galileo

NASA Image and Video Library

2017-02-08

This mosaic of images includes the most detailed view of the surface of Jupiter's moon Europa obtained by NASA's Galileo mission. The topmost footprint is the highest resolution image taken by Galileo at Europa. It was obtained at an original image scale of 19 feet (6 meters) per pixel. The other seven images in this observation were obtained at a resolution of 38 feet (12 meters) per pixel, thus the mosaic, including the top image, has been projected at the higher image scale. The top image is also provided at its original resolution, as a separate image file. It includes a vertical black line that resulted from missing data that was not transmitted by Galileo. This is the highest resolution view of Europa available until a future mission visits the icy moon. The right side of the image was previously published as PIA01180. Although this data has been publicly available in NASA's Planetary Data System archive for many years, NASA scientists have not previously combined these images into a mosaic for public release. This observation was taken with the sun relatively high in the sky, so most of the brightness variations visible here are due to color differences in the surface material rather than shadows. Bright ridge tops are paired with darker valleys, perhaps due to a process in which small temperature variations allow bright frost to accumulate in slightly colder, higher-elevation locations. http://photojournal.jpl.nasa.gov/catalog/PIA21431

Europa Ice Rafts

NASA Technical Reports Server (NTRS)

1997-01-01

This high resolution image shows the ice-rich crust of Europa, one of the moons of Jupiter. Seen here are crustal plates ranging up to 13 kilometers (8 miles) across, which have been broken apart and 'rafted' into new positions, superficially resembling the disruption of pack-ice on polar seas during spring thaws on Earth. The size and geometry of these features suggest that motion was enabled by ice-crusted water or soft ice close to the surface at the time of disruption.

The area shown is about 34 kilometers by 42 kilometers (21 miles by 26 miles), centered at 9.4 degrees north latitude, 274 degrees west longitude, and the resolution is 54 meters (59 yards). This picture was taken by the Solid State Imaging system on board the Galileo spacecraft on February 20, 1997, from a distance of 5,340 kilometers (3,320 miles) during the spacecraft's close flyby of Europa.

The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington D.C. This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at: http://galileo.jpl.nasa.gov.

Akon - A Penetrator for Europa

NASA Astrophysics Data System (ADS)

Jones, Geraint

2016-04-01

Jupiter's moon Europa is one of the most intriguing objects in our Solar System. This 2000km-wide body has a geologically young solid water ice crust that is believed to cover a global ocean of liquid water. The presence of this ocean, together with a source of heating through tidal forces, make Europa a conceivable location for extraterrestrial life. The science case for exploring all aspects of this icy world is compelling. NASA has selected the Europa Mission (formerly Europa Clipper) to study Europa in detail in the 2020s through multiple flybys, and ESA's JUICE mission will perform two flybys of the body in the 2030s. The US agency has extended to the European Space Agency an invitation to provide a contribution to their mission. European scientists interested in Europa science and exploration are currently organizing themselves, in the framework of a coordinated Europa M5 Inititative to study concurrently the main options for this ESA contribution, from a simple addition of individual instruments to the NASA spacecraft, to a lander to investigate Europa's surface in situ. A high speed lander - a penetrator - is by far the most promising technology to achieve this latter option within the anticipated mass constraints, and studies of such a hard lander, many funded by ESA, are now at an advanced level. An international team to formally propose an Europa penetrator to ESA in response to the anticipated ESA M5 call is growing. The working title of this proposal is Akon (Άκων), named after the highly accurate javelin gifted to Europa by Zeus in ancient Greek mythology. We present plans for the Akon penetrator, which would impact Europa's surface at several hundred metres per second, and travel up to several metres into the moon's subsurface. To achieve this, the penetrator would be delivered to the surface by a dedicated descent module, to be destroyed on impact following release of the penetrator above the surface. It is planned that the instruments to be

The Ultraviolet Spectrograph on the Europa Mission (Europa-UVS)

NASA Astrophysics Data System (ADS)

Retherford, K. D.; Gladstone, R.; Greathouse, T. K.; Steffl, A.; Davis, M. W.; Feldman, P. D.; McGrath, M. A.; Roth, L.; Saur, J.; Spencer, J. R.; Stern, S. A.; Pope, S.; Freeman, M. A.; Persyn, S. C.; Araujo, M. F.; Cortinas, S. C.; Monreal, R. M.; Persson, K. B.; Trantham, B. J.; Versteeg, M. H.; Walther, B. C.

2015-12-01

NASA's Europa multi-flyby mission is designed to provide a diversity of measurements suited to enrich our understanding of the potential habitability of this intriguing ocean world. The Europa mission's Ultraviolet Spectrograph, Europa-UVS, is the sixth in a series of successful ultraviolet imaging spectrographs (Rosetta-Alice, New Horizons Pluto-Alice, LRO-LAMP) and, like JUICE-UVS (now under Phase B development), is largely based on the most recent of these to fly, Juno-UVS. Europa-UVS observes photons in the 55-210 nm wavelength range, at moderate spectral and spatial resolution along a 7.5° slit. Three distinct apertures send light to the off-axis telescope mirror feeding the long-slit spectrograph: i) a main entrance airglow port is used for most observations (e.g., airglow, aurora, surface mapping, and stellar occultations); ii) a high-spatial-resolution port consists of a small hole in an additional aperture door, and is used for detailed observations of bright targets; and iii) a separate solar port allows for solar occultations, viewing at a 60° offset from the nominal payload boresight. Photon event time-tagging (pixel list mode) and programmable spectral imaging (histogram mode) allow for observational flexibility and optimal science data management. As on Juno-UVS, the effects of penetrating electron radiation on electronic parts and data quality are mitigated through contiguous shielding, filtering of pulse height amplitudes, management of high-voltage settings, and careful use of radiation-hard parts. The science goals of Europa-UVS are to: 1) Determine the composition & chemistry, source & sinks, and structure & variability of Europa's atmosphere, from equator to pole; 2) Search for and characterize active plumes in terms of global distribution, structure, composition, and variability; 3) Explore the surface composition & microphysics and their relation to endogenic & exogenic processes; and 4) Investigate how energy and mass flow in the Europa

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

Featured Image: Active Cryovolcanism on Europa?

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2017-05-01

Nighttime thermal image from the Galileo Photopolarimeter-Radiometer, revealing a thermal anomaly around the region where the plumes were observed. [Sparks et al. 2017]This image shows a 1320 900 km, high-resolution Galileo/Voyager USGS map of the surface of Europa, one of Jupiters moons. In March 2014, observations of Europa revealed a plume on its icy surface coming from somewhere within the green ellipse. In February 2016, another plume was observed, this time originating from somewhere within the cyan ellipse. In addition, a nighttime thermal image from the Galileo Photopolarimeter-Radiometer has revealed a thermal anomaly a region of unusually high temperature near the same location. In a recent study led by William Sparks (Space Telescope Science Institute), a team of scientists presents these observations and argues that they provide mounting evidence of active water-vapor venting from ongoing cryovolcanism beneath Europas icy surface. If this is true, then Europas surface is active and provides access to the liquid water at depth boosting the case for Europas potential habitability and certainly making for an interesting target point for future spacecraft exploration of this moon. For more information, check out the paper below!CitationW. B. Sparks et al 2017 ApJL 839 L18. doi:10.3847/2041-8213/aa67f8

The Europa Clipper Mission Concept

NASA Astrophysics Data System (ADS)

Pappalardo, Robert; Goldstein, Barry; Magner, Thomas; Prockter, Louise; Senske, David; Paczkowski, Brian; Cooke, Brian; Vance, Steve; Wes Patterson, G.; Craft, Kate

2014-05-01

A NASA-appointed Science Definition Team (SDT), working closely with a technical team from the Jet Propulsion Laboratory (JPL) and the Applied Physics Laboratory (APL), recently considered options for a future strategic mission to Europa, with the stated science goal: Explore Europa to investigate its habitability. The group considered several mission options, which were fully technically developed, then costed and reviewed by technical review boards and planetary science community groups. There was strong convergence on a favored architecture consisting of a spacecraft in Jupiter orbit making many close flybys of Europa, concentrating on remote sensing to explore the moon. Innovative mission design would use gravitational perturbations of the spacecraft trajectory to permit flybys at a wide variety of latitudes and longitudes, enabling globally distributed regional coverage of the moon's surface, with nominally 45 close flybys at altitudes from 25 to 100 km. We will present the science and reconnaissance goals and objectives, a mission design overview, and the notional spacecraft for this concept, which has become known as the Europa Clipper. The Europa Clipper concept provides a cost-efficient means to explore Europa and investigate its habitability, through understanding the satellite's ice and ocean, composition, and geology. The set of investigations derived from the Europa Clipper science objectives traces to a notional payload for science, consisting of: Ice Penetrating Radar (for sounding of ice-water interfaces within and beneath the ice shell), Topographical Imager (for stereo imaging of the surface), ShortWave Infrared Spectrometer (for surface composition), Neutral Mass Spectrometer (for atmospheric composition), Magnetometer and Langmuir Probes (for inferring the satellite's induction field to characterize an ocean), and Gravity Science (to confirm an ocean).The mission would also include the capability to perform reconnaissance for a future lander

Regional Mosaic of Chaos and Gray Band on Europa

NASA Technical Reports Server (NTRS)

1997-01-01

This mosaic of part of Jupiter's moon, Europa, shows a region that is characterized by mottled (dark and splotchy) terrain. The images in this mosaic were obtained by Solid State Imaging (CCD) system on NASA's Galileo spacecraft during its eleventh orbit around Jupiter. North is to the top of the image, and the sun illuminates the scene from the right. Prior to obtaining these pictures, the age and origin of mottled terrain were not known. As seen here, the mottled appearance results from areas of the bright, icy crust that have been broken apart (known as 'chaos' terrain), exposing a darker underlying material. This terrain is typified by the area in the upper right-hand part of the image. The mottled terrain represents some of the most recent geologic activity on Europa. Also shown in this image is a smooth, gray band (lower part of image) representing a zone where the Europan crust has been fractured, separated, and filled in with material derived from the interior. The chaos terrain and the gray band show that this satellite has been subjected to intense geological deformation.

The mosaic, centered at 2.9 degrees south latitude and 234.1 degrees west longitude, covers an area of 365 kilometers by 335 kilometers (225 miles by 210 miles). The smallest distinguishable features in the image are about 460 meters (1500 feet) across. These images were obtained on November 6, 1997, when the Galileo spacecraft was approximately 21,700 kilometers (13,237 miles) from Europa.

The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC. JPL is a division of California Institute of Technology.

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo home page at URL http://galileo.jpl.nasa.gov. Background information and educational context can be found at URL http://www.jpl.nasa.gov/galileo/sepo

The Contribution of Io-Raised Tides to Europa's Diurnally-Varying Surface Stresses

NASA Technical Reports Server (NTRS)

Rhoden, Alyssa Rose; Hurford, Terry A,; Manga, Michael

2011-01-01

Europa's icy surface records a rich history of geologic activity, Several features appear to be tectonic in origin and may have formed in response to Europa's daily-varying tidal stress [I]. Strike-slip faults and arcuate features called cycloids have both been linked to the patterns of stress change caused by eccentricity and obliquity [2J[3]. In fact, as Europa's obliquity has not been directly measured, observed tectonic patterns arc currently the best indicators of a theoretically supported [4] non-negligible obliquity. The diurnal tidal stress due to eccentricity is calculated by subtracting the average (or static) tidal shape of Europa generated by Jupiter's gravitational field from the instantaneous shape, which varies as Europa moves through its eccentric orbit [5]. In other words, it is the change of shape away from average that generates tidal stress. One might expect tidal contributions from the other large moons of Jupiter to be negligible given their size and the height of the tides they raise on Europa versus Jupiter's mass and the height of the tide it raises on Europa, However, what matters for tidally-induced stress is not how large the lo-raised bulge is compared to the Jupiter-raised bulge but rather the differences bet\\Veen the instantaneous and static bulges in each case. For example, when Europa is at apocenter, Jupiter raises a tide 30m lower than its static tide. At the same time, 10 raises a tide about 0.5m higher than its static tide. Hence, the change in Io's tidal distortion is about 2% of the change in the Jovian distortion when Europa is at apocenter

The Jupiter Icy Moons Orbiter reference trajectory

NASA Technical Reports Server (NTRS)

Whiffen, Gregory J.; Lam, Try

2006-01-01

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

Europa Ice

NASA Image and Video Library

1998-05-08

This image of Jupiter icy satellite Europa shows surface features such as domes and ridges, as well as a region of disrupted terrain including crustal plates which are thought to have broken apart and rafted into new positions.

Science and Reconnaissance from the Europa Clipper Mission Concept: Exploring Europa's Habitability

NASA Astrophysics Data System (ADS)

Pappalardo, Robert; Senske, David; Prockter, Louise; Paczkowski, Brian; Vance, Steve; Goldstein, Barry; Magner, Thomas; Cooke, Brian

2015-04-01

Europa is recognized by the Planetary Science De-cadal Survey as a prime candidate to search for a pre-sent-day habitable environment in our solar system. As such, NASA has pursued a series of studies, facilitated by a Europa Science Definition Team (SDT), to define a strategy to best advance our scientific understanding of this icy world with the science goal: Explore Europa to investigate its habitability. (In June of 2014, the SDT completed its task of identifying the overarching science objectives and investigations.) Working in concert with a technical team, a set of mission archi-tectures were evaluated to determine the best way to achieve the SDT defined science objectives. The fa-vored architecture would consist of a spacecraft in Ju-piter orbit making many close flybys of Europa, con-centrating on remote sensing to explore the moon. In-novative mission design would use gravitational per-turbations of the spacecraft trajectory to permit flybys at a wide variety of latitudes and longitudes, enabling globally distributed regional coverage of Europa's sur-face, with nominally 45 close flybys, typically at alti-tudes from 25 to 100 km. This concept has become known as the Europa Clipper. The Europa SDT recommended three science ob-jectives for the Europa Clipper: Ice Shell and Ocean: Characterize the ice shell and any subsurface water, including their heterogeneity, ocean properties, and the nature of surface-ice-ocean exchange; Composition: Understand the habitability of Europa's ocean through composition and chemistry; and Geology: Understand the formation of surface features, including sites of recent or current activity, and characterize high science interest localities. The Europa SDT also considered implications of the Hubble Space Telescope detection of possible plumes at Europa. To feed forward to potential subsequent future ex-ploration that could be enabled by a lander, it was deemed that the Europa Clipper mission concept should provide the

Modeling Minor Constituents of Europa's Atmosphere

NASA Astrophysics Data System (ADS)

Cassidy, T. A.; Johnson, R. E.

2007-12-01

A spacecraft orbiting Jupiter's moon Europa, of the sort considered by both ESA and NASA, would provide an opportunity to determine the composition and morphology of its tenuous atmosphere. Europa's atmosphere, though tenuous, has been detected by Earth-based telescopes. Its O2 atmosphere was detected from Earth orbit and its much thinner alkali atmosphere was detected by ground-based telescopes. Many other species are expected based on surface reflectance spectra, such as H2O, Sn, SO2, CO2, H2O2. I will discuss the issues involved in the modeling of these as-yet-undetected components. Previous theoretical studies and observations of the atmosphere produced important conclusions about the surface and its interaction with the Jovian magnetosphere. The modeling and detection of minor components could reveal much more. Of particular interest is the detectability of these species with an orbiting mass spectrometer or more distant light spectrometer.

A Look Inside the Juno Mission to Jupiter

NASA Technical Reports Server (NTRS)

Grammier, Richard S.

2008-01-01

Juno, the second mission within the New Frontiers Program, is a Jupiter polar orbiter mission designed to return high-priority science data that spans across multiple divisions within NASA's Science Mission Directorate. Juno's science objectives, coupled with the natural constraints of a cost-capped, PI-led mission and the harsh environment of Jupiter, have led to a very unique mission and spacecraft design.

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

NASA Technical Reports Server (NTRS)

Edwards, Dave

2012-01-01

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

Photographer : JPL Europa , the smallest of the Galilean satellites, or Moons , of Jupiter , is seen

NASA Technical Reports Server (NTRS)

1979-01-01

Photographer : JPL Europa , the smallest of the Galilean satellites, or Moons , of Jupiter , is seen here as taken by Voyager 1. Range : 2 million km (1.2 million miles) is centered at about the 300 degree Meridian. The bright areas are probably ice deposits, while the dark may be rocky surface or areas of more patchy ice distribution. Most unusual features are systems of linear structures crossing the surface in various directions. Of these, some of which are over 1000 km. long , & 2 or 3 hundred km. wide, may be faults which have disrupted the surface.

Hot Jupiter with Hidden Water (Artist Concept)

NASA Image and Video Library

2016-06-08

Hot Jupiters, exoplanets around the same size as Jupiter that orbit very closely to their stars, often have cloud or haze layers in their atmospheres. This may prevent space telescopes from detecting atmospheric water that lies beneath the clouds, according to a study in the Astrophysical Journal. As much as half of the water in the atmospheres of these exoplanets may be blocked by these clouds or hazes, research suggests. The study, led by researchers at NASA's Jet Propulsion Laboratory, Pasadena, California, examined hot Jupiters that had been observed with the Hubble Space Telescope. http://photojournal.jpl.nasa.gov/catalog/PIA20687

Riding the Banzai Pipeline at Jupiter: Balancing Low Delta-V and Low Radiation to Reach Europa

NASA Technical Reports Server (NTRS)

McElrath, Timothy P.; Campagnola, Stefano; Strange, Nathan J.

2012-01-01

Europa's tantalizing allure as a possible haven for life comes cloaked in a myriad of challenges for robotic spacecraft exploration. Not only are the propulsive requirements high and the solar illumination low, but the radiation environment at Jupiter administers its inexorable death sentence on any electronics dispatched to closely examine the satellite. So to the usual trades of mass, delta-V, and cost, we must add radiation dose, which tugs the trajectory solution in a contrary direction. Previous studies have concluded that adding radiation shielding mass is more efficient than using ?V to reduce the exposure time, but that position was recently challenged by a study focusing on delivering simple landers to the Europa surface. During this work, a new trajectory option was found to occupy a strategic location in the delta-V/radiation continuum - we call it the "Banzai pipeline" due to the visual similarity with the end-on view down a breaking wave, as shown in the following figures.

Stability of orbits around planetary satellites considering a disturbing body in an elliptical orbit: Applications to Europa and Ganymede

NASA Astrophysics Data System (ADS)

Cardoso dos Santos, Josué; Carvalho, Jean Paulo; Vilhena de Moraes, Rodolpho

Europa and Ganymede are two of the four Jupiter’s moons which compose the Galilean satellite. These ones are planetary satellites of greater interest at the present moment among the scientific community. There are some missions being planned to visit them and and the Jovian system. One of them is the cooperation between NASA and ESA for the Europa Jupiter System Mission (EJSM). In this mission are planned the insertion of the spacecrafts JEO (Jupiter Europa Orbiter) and JGO (Jupiter Ganymede Orbiter) into Europa and Ganymede’s orbit. Thus, there is a great necessity for having a better comprehension of the dynamics of the orbits around this planetary satellite. This comprehension is essential for the success of this type of mission. In this context, this work aims to perform a search for low-altitude orbits around these planetary satellites. An emphasis is given in polar orbits. These orbits can be useful in the planning of aerospace activities to be conducted around this planetary satellite, with respect to the stability of orbits of artificial satellites. The study considers orbits of an artificial satellite around Europa and Ganymede under the influence of the third-body perturbation (the gravitational attraction of Jupiter) and the polygenic perturbations. These last ones occur due to forces such as the non-uniform distribution of mass (J2 and J3) of the main (central) body. A simplified dynamic model for polygenic perturbations is used. A new model for the third-body disturbance is presented considering it in an elliptical orbit. The Lagrange planetary equations, which compose a system of nonlinear differential equations, are used to describe the orbital motion of the artificial satellite around Ganymede. The equations showed here are developed in closed form to avoid expansions in inclination and eccentricity.

Io and Europa Meet Again

NASA Technical Reports Server (NTRS)

2007-01-01

This beautiful image of the crescents of volcanic Io and more sedate Europa is a combination of two New Horizons images taken March 2, 2007, about two days after New Horizons made its closest approach to Jupiter. A lower-resolution color image snapped by the Multispectral Visual Imaging Camera (MVIC) at 10:34 universal time (UT) has been merged with a higher-resolution black-and-white image taken by the Long Range Reconnaissance Imager (LORRI) at 10:23 UT. The composite image shows the relative positions of Io and Europa, which were moving past each other during the image sequence, as they were at the time the LORRI image was taken.

This image was taken from a range of 4.6 million kilometers (2.8 million miles) from Io and 3.8 million kilometers (2.4 million miles) from Europa. Although the moons appear close together in this view, a gulf of 790,000 kilometers (490,000 miles) separates them. Io's night side is lit up by light reflected from Jupiter, which is off the frame to the right. Europa's night side is dark, in contrast to Io, because this side of Europa faces away from Jupiter.

Here Io steals the show with its beautiful display of volcanic activity. Three volcanic plumes are visible. Most conspicuous is the enormous 300-kilometer (190-mile) high plume from the Tvashtar volcano at the 11 o'clock position on Io's disk. Two much smaller plumes are also visible: that from the volcano Prometheus, at the 9 o'clock position on the edge of Io's disk, and from the volcano Amirani, seen between Prometheus and Tvashtar along Io's terminator (the line dividing day and night). The Tvashtar plume appears blue because of the scattering of light by tiny dust particles ejected by the volcanoes, similar to the blue appearance of smoke. In addition, the contrasting red glow of hot lava can be seen at the source of the Tvashtar plume.

The images are centered at 1 degree North, 60 degrees West on Io, and 0 degrees North, 149 degrees West on Europa. The color

Two Moons Meet over Jupiter

NASA Technical Reports Server (NTRS)

2007-01-01

This beautiful image of the crescents of volcanic Io and more sedate Europa was snapped by New Horizons' color Multispectral Visual Imaging Camera (MVIC) at 10:34 UT on March 2, 2007, about two days after New Horizons made its closest approach to Jupiter.

The picture was one of a handful of the Jupiter system that New Horizons took primarily for their artistic, rather than scientific value. This particular scene was suggested by space enthusiast Richard Hendricks of Austin, Texas, in response to an Internet request by New Horizons scientists for evocative, artistic imaging opportunities at Jupiter.

This image was taken from a range of 4.6 million kilometers (2.8 million miles) from Io and 3.8 million kilometers (2.4 million miles) from Europa. Although the moons appear close in this view, a gulf of 790,000 kilometers (490,000 miles) separates them. The night side of Io is illuminated here by light reflected from Jupiter, which is out of the frame to the right. Europa's night side is completely dark, in contrast to Io, because that side of Europa faces away from Jupiter.

Here, Io steals the show with its beautiful display of volcanic activity. Three volcanic plumes are visible. Most conspicuous is the enormous 300-kilometer (190-mile) -high plume from the Tvashtar volcano at the 11 o'clock position on Io's disk. Two much smaller plumes are barely visible: one from the volcano Prometheus, at the 9 o'clock position on the edge of Io's disk, and one from the volcano Amirani, seen between Prometheus and Tvashtar along Io's terminator (the line dividing day and night). The plumes appear blue because of the scattering of light by tiny dust particles ejected by the volcanoes, similar to the blue appearance of smoke. In addition, the contrasting red glow of hot lava can be seen at the source of the Tvashtar plume.

The images are centered at 1 degree north, 60 degrees west on Io, and 0 degrees north, 149 degrees west on Europa. The color in this

Science Objectives and Mission Concepts for Europa Exploration

NASA Astrophysics Data System (ADS)

Tamppari, L. K.; Senske, D. A.; Johnson, T. V.; Oberto, R.; Zimmerman, W.; JPL's Team-X Team

2000-10-01

rate. Second, the mission design will be discussed, including candidate launch and arrival dates and landing ellipse issues. Third, the technology developments required and other issues will be presented. This poster presentation will provide an opportunity for the science community to influence future work on developing a Europa architecture, including refinements to a Europa Lander , other mission concepts, and further science objective identification and prioritization. This work was carried out at Caltech's Jet Propulsion Laboratory under a contract from NASA. [1] Morrison, D., Introduction to the Satellites of Jupiter in Satellites of Jupiter, Morrison ed., 1982. [2] Space Studies Board, A Strategy for the Exploration of Europa, National Academy Press, Washington D. C., 1999.

Ridges on Europa

NASA Image and Video Library

1997-12-18

This view of Jupiter's moon Europa shows a portion of the surface that has been highly disrupted by fractures and ridges. This picture covers an area about 238 kilometers (150 miles) wide by 225 kilometers (140 miles), or about the distance between Los Angeles and San Diego. Symmetric ridges in the dark bands suggest that the surface crust was separated and filled with darker material, somewhat analogous to spreading centers in the ocean basins of Earth. Although some impact craters are visible, their general absence indicates a youthful surface. The youngest ridges, such as the two features that cross the center of the picture, have central fractures, aligned knobs, and irregular dark patches. These and other features could indicate cryovolcanism, or processes related to eruption of ice and gases. This picture, centered at 16 degrees south latitude, 196 degrees west longitude, was taken at a distance of 40,973 kilometers (25,290 mi) on November 6, 1996 by the Galileo spacecraft solid state imaging television camera onboard the Galileo spacecraft during its third orbit around Jupiter. http://photojournal.jpl.nasa.gov/catalog/PIA00518

A closer look at Chaos on Europa

NASA Technical Reports Server (NTRS)

1998-01-01

This mosaic of the Conamara Chaos region on Jupiter's moon, Europa, clearly indicates relatively recent resurfacing of Europa's surface. Irregularly shaped blocks of water ice were formed by the break up and movement of the existing crust. The blocks were shifted, rotated, and even tipped and partially submerged within a mobile material that was either liquid water, warm mobile ice, or an ice and water slush. The presence of young fractures cutting through this region indicates that the surface froze again into solid, brittle ice.

The background image in this picture was taken during Galileo's sixth orbit of Jupiter in February, 1997. Five very high resolution images which were taken during the spacecraft's twelfth orbit in December, 1997 provide an even closer look at some of the details. This mosaic shows some of the high resolution data inset into the context of this tumultuous region.

North is to the top of the picture, and the sun illuminates the scene from the east (right). The picture, centered at 9 degrees north latitude and 274 degrees west longitude, covers an area approximately 35 by 50 kilometers (20 by 30 miles). The finest details visible in the very high resolution insets are about 20 meters (22 yards) across, and in the background image, 100 meters (110 yards) across. The insets were taken on December 16, 1997, at ranges as close as 880 kilometers (550 miles) by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

Cross-cutting Relationships of Surface Features on Europa

NASA Technical Reports Server (NTRS)

1997-01-01

This image of Jupiter's moon Europa shows a very complex terrain of ridges and fractures. The absence of large craters and the low number of small craters indicates that this surface is geologically young. The relative ages of the ridges can be determined by using the principle of cross-cutting relationships; i.e. older features are cross-cut by younger features. Using this principle, planetary geologists are able to unravel the sequence of events in this seemingly chaotic terrain to unfold Europa's unique geologic history.

The spacecraft Galileo obtained this image on February 20, 1997. The area covered in this image is approximately 11 miles (18 kilometers) by 8.5 miles (14 kilometers) across, near 15 North, 273 West. North is toward the top of the image, with the sun illuminating from the right.

The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

Geology of Europa

NASA Technical Reports Server (NTRS)

Greeley, R.; Chyba, C.; Head, J. W.; McCord, T.; McKinnon, W. B.; Pappalardo, R. T.

2004-01-01

Europa is a rocky object of radius 1565 km (slightly smaller than Earth s moon) and has an outer shell of water composition estimated to be of order 100 km thick, the surface of which is frozen. The total volume of water is about 3 x 10(exp 9) cubic kilometers, or twice the amount of water on Earth. Moreover, like its neighbor Io, Europa experiences internal heating generated from tidal flexing during its eccentric orbit around Jupiter. This raises the possibility that some of the water beneath the icy crust is liquid. The proportion of rock to ice, the generation of internal heat, and the possibility of liquid water make Europa unique in the Solar System. In this chapter, we outline the sources of data available for Europa (with a focus on the Galileo mission), review previous and on-going research on its surface geology, discuss the astrobiological potential of Europa, and consider plans for future exploration.

Thick or Thin Ice Shell on Europa?

NASA Technical Reports Server (NTRS)

2007-01-01

Scientists are all but certain that Europa has an ocean underneath its icy surface, but they do not know how thick this ice might be. This artist concept illustrates two possible cut-away views through Europa's ice shell. In both, heat escapes, possibly volcanically, from Europa's rocky mantle and is carried upward by buoyant oceanic currents. If the heat from below is intense and the ice shell is thin enough (left), the ice shell can directly melt, causing what are called 'chaos' on Europa, regions of what appear to be broken, rotated and tilted ice blocks. On the other hand, if the ice shell is sufficiently thick (right), the less intense interior heat will be transferred to the warmer ice at the bottom of the shell, and additional heat is generated by tidal squeezing of the warmer ice. This warmer ice will slowly rise, flowing as glaciers do on Earth, and the slow but steady motion may also disrupt the extremely cold, brittle ice at the surface. Europa is no larger than Earth's moon, and its internal heating stems from its eccentric orbit about Jupiter, seen in the distance. As tides raised by Jupiter in Europa's ocean rise and fall, they may cause cracking, additional heating and even venting of water vapor into the airless sky above Europa's icy surface. (Artwork by Michael Carroll.)

NASA's Hubble Shows Jupiter's Great Red Spot is Smaller than Ever

NASA Image and Video Library

2014-05-15

An image of Jupiter's Great Red Spot taken in 2014 with Hubble's WFC3 camera. The spot has a diameter here of 16 000km. -- Jupiter's trademark Great Red Spot -- a swirling anti-cyclonic storm larger than Earth -- has shrunk to its smallest size ever measured. According to Amy Simon of NASA's Goddard Space Flight Center in Greenbelt, Maryland, recent NASA Hubble Space Telescope observations confirm the Great Red Spot now is approximately 10,250 miles across. Astronomers have followed this downsizing since the 1930s. Historic observations as far back as the late 1800s gauged the storm to be as large as 25,500 miles on its long axis. NASA Voyager 1 and Voyager 2 flybys of Jupiter in 1979 measured it to be 14,500 miles across. In 1995, a Hubble photo showed the long axis of the spot at an estimated 13,020 miles across. And in a 2009 photo, it was measured at 11,130 miles across. Beginning in 2012, amateur observations revealed a noticeable increase in the rate at which the spot is shrinking -- by 580 miles per year -- changing its shape from an oval to a circle. Read more: 1.usa.gov/1mvuo0R Credit: NASA/ESA 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

NASA's Hubble Shows Jupiter's Great Red Spot is Smaller than Ever

NASA Image and Video Library

2014-05-15

This full-disc image of Jupiter was taken on 21 April 2014 with Hubble's Wide Field Camera 3 (WFC3). -- Jupiter's trademark Great Red Spot -- a swirling anti-cyclonic storm larger than Earth -- has shrunk to its smallest size ever measured. According to Amy Simon of NASA's Goddard Space Flight Center in Greenbelt, Maryland, recent NASA Hubble Space Telescope observations confirm the Great Red Spot now is approximately 10,250 miles across. Astronomers have followed this downsizing since the 1930s. Historic observations as far back as the late 1800s gauged the storm to be as large as 25,500 miles on its long axis. NASA Voyager 1 and Voyager 2 flybys of Jupiter in 1979 measured it to be 14,500 miles across. In 1995, a Hubble photo showed the long axis of the spot at an estimated 13,020 miles across. And in a 2009 photo, it was measured at 11,130 miles across. Beginning in 2012, amateur observations revealed a noticeable increase in the rate at which the spot is shrinking -- by 580 miles per year -- changing its shape from an oval to a circle. Read more: 1.usa.gov/1mvuo0R Credit: NASA/ESA 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 Plasma Instrument for Magnetic Sounding (PIMS) on The Europa Clipper Mission

NASA Astrophysics Data System (ADS)

Westlake, Joseph H.; McNutt, Ralph L.; Kasper, Justin C.; Case, Anthony W.; Grey, Matthew P.; Kim, Cindy K.; Battista, Corina C.; Rymer, Abigail; Paty, Carol S.; Jia, Xianzhe; Stevens, Michael L.; Khurana, Krishan; Kivelson, Margaret G.; Slavin, James A.; Korth, Haje H.; Smith, Howard T.; Krupp, Norbert; Roussos, Elias; Saur, Joachim

2016-10-01

The Europa Clipper mission is equipped with a sophisticated suite of 9 instruments to study Europa's interior and ocean, geology, chemistry, and habitability from a Jupiter orbiting spacecraft. The Plasma Instrument for Magnetic Sounding (PIMS) on Europa Clipper is a Faraday Cup based plasma instrument whose heritage dates back to the Voyager spacecraft. PIMS will measure the plasma that populates Jupiter's magnetosphere and Europa's ionosphere. The science goals of PIMS are to: 1) estimate the ocean salinity and thickness by determining Europa's magnetic induction response, corrected for plasma contributions; 2) assess mechanisms responsible for weathering and releasing material from Europa's surface into the atmosphere and ionosphere; and 3) understand how Europa influences its local space environment and Jupiter's magnetosphere and vice versa.Europa is embedded in a complex Jovian magnetospheric plasma, which rotates with the tilted planetary field and interacts dynamically with Europa's ionosphere affecting the magnetic induction signal. Plasma from Io's temporally varying torus diffuses outward and mixes with the charged particles in Europa's own torus producing highly variable plasma conditions at Europa. PIMS works in conjunction with the Interior Characterization of Europa using Magnetometry (ICEMAG) investigation to probe Europa's subsurface ocean. This investigation exploits currents induced in Europa's interior by the moon's exposure to variable magnetic fields in the Jovian system to infer properties of Europa's subsurface ocean such as its depth, thickness, and conductivity. This technique was successfully applied to Galileo observations and demonstrated that Europa indeed has a subsurface ocean. While these Galileo observations contributed to the renewed interest in Europa, due to limitations in the observations the results raised major questions that remain unanswered. PIMS will greatly refine our understanding of Europa's global liquid ocean by

The Plasma Instrument for Magnetic Sounding (PIMS) on The Europa Clipper Mission

NASA Astrophysics Data System (ADS)

Westlake, J. H.; McNutt, R. L., Jr.; Kasper, J. C.; Battista, C.; Case, A. W.; Cochrane, C.; Grey, M.; Jia, X.; Kivelson, M.; Kim, C.; Korth, H.; Khurana, K. K.; Krupp, N.; Paty, C. S.; Roussos, E.; Rymer, A. M.; Stevens, M. L.; Slavin, J. A.; Smith, H. T.; Saur, J.; Coren, D.

2017-12-01

The Europa Clipper mission is equipped with a sophisticated suite of 9 instruments to study Europa's interior and ocean, geology, chemistry, and habitability from a Jupiter orbiting spacecraft. The Plasma Instrument for Magnetic Sounding (PIMS) on Europa Clipper is a Faraday Cup based plasma instrument whose heritage dates back to the Voyager spacecraft. PIMS will measure the plasma that populates Jupiter's magnetosphere and Europa's ionosphere. The science goals of PIMS are to: 1) estimate the ocean salinity and thickness by determining Europa's magnetic induction response, corrected for plasma contributions; 2) assess mechanisms responsible for weathering and releasing material from Europa's surface into the atmosphere and ionosphere; and 3) understand how Europa influences its local space environment and Jupiter's magnetosphere and vice versa. Europa is embedded in a complex Jovian magnetospheric plasma, which rotates with the tilted planetary field and interacts dynamically with Europa's ionosphere affecting the magnetic induction signal. Plasma from Io's temporally varying torus diffuses outward and mixes with the charged particles in Europa's own torus producing highly variable plasma conditions at Europa. PIMS works in conjunction with the Interior Characterization of Europa using Magnetometry (ICEMAG) investigation to probe Europa's subsurface ocean. This investigation exploits currents induced in Europa's interior by the moon's exposure to variable magnetic fields in the Jovian system to infer properties of Europa's subsurface ocean such as its depth, thickness, and conductivity. This technique was successfully applied to Galileo observations and demonstrated that Europa indeed has a subsurface ocean. While these Galileo observations contributed to the renewed interest in Europa, due to limitations in the observations the results raised major questions that remain unanswered. PIMS will greatly refine our understanding of Europa's global liquid ocean by

Jupiter’s moon Europa

NASA Image and Video Library

2014-01-24

This composite image shows suspected plumes of water vapor erupting at the 7 o’clock position off the limb of Jupiter’s moon Europa. The plumes, photographed by NASA’s Hubble’s Space Telescope Imaging Spectrograph, were seen in silhouette as the moon passed in front of Jupiter. Hubble’s ultraviolet sensitivity allowed for the features -- rising over 100 miles (160 kilometers) above Europa’s icy surface -- to be discerned. The water is believed to come from a subsurface ocean on Europa. The Hubble data were taken on January 26, 2014. The image of Europa, superimposed on the Hubble data, is assembled from data from the Galileo and Voyager missions.

Joint Europa Mission (JEM) : A multi-scale study of Europa to characterize its habitability and search for life.

NASA Astrophysics Data System (ADS)

Blanc, Michel; Prieto Ballesteros, Olga; Andre, Nicolas; Cooper, John F.

2017-04-01

Europa is the closest and probably the most promising target to perform a comprehensive characterization of habitability and search for extant life. We propose that NASA and ESA join forces to design an ambitious planetary mission we call JEM (for Joint Europa Mission) to reach this objective. JEM will be assigned the following overarching goal: Understand Europa as a complex system responding to Jupiter system forcing, characterize the habitability of its potential biosphere, and search for life in its surface, sub-surface and exosphere. Our observation strategy to address these goals will combine three scientific measurement sequences: measurements on a high-latitude, low-latitude Europan orbit providing a continuous and global mapping of planetary fields (magnetic and gravity) and of the neutral and charged environment during a period of three months; in-situ measurements at the surface, using a soft lander operating during 35 days, to search for bio-signatures at the surface and sub-surface and operate a geophysical station; measurements of the chemical composition of the very low exosphere and plumes in search for biomolecules. The implementation of these three observation sequences will rest on the combination of two science platforms equipped with the most advanced instrumentation: a soft lander to perform all scientific measurements at the surface and sub-surface at a selected landing site, and a carrier/relay/orbiter to perform the orbital survey and descent sequences. In this concept, the orbiter will perform science operations during the relay phase on a carefully optimized halo orbit of the Europa-Jupiter system before moving to its final Europan orbit. The design of both orbiter and lander instruments will have to accommodate the very challenging radiation mitigation and Planetary Protection issues. The proposed lander science platform is composed of a geophysical station and of two complementary astrobiology facilities dedicated to bio

Europa Lander Mission Concept (Artist Rendering)

NASA Image and Video Library

2017-02-08

This artist's rendering illustrates a conceptual design for a potential future mission to land a robotic probe on the surface of Jupiter's moon Europa. The lander is shown with a sampling arm extended, having previously excavated a small area on the surface. The circular dish on top is a dual-purpose high-gain antenna and camera mast, with stereo imaging cameras mounted on the back of the antenna. Three vertical shapes located around the top center of the lander are attachment points for cables that would lower the rover from a sky crane, which is envisioned as the landing system for this mission concept. http://photojournal.jpl.nasa.gov/catalog/PIA21048

Taste of the Ocean on Europa Surface Artist Concept

NASA Image and Video Library

2013-03-05

Based on new evidence from Jupiter moon Europa, astronomers hypothesize that chloride salts bubble up from its global liquid ocean and reach the frozen surface where they are bombarded with sulfur from volcanoes on Jupiter innermost large moon, Io.

Topography within Europa's Mannann'an crater

NASA Technical Reports Server (NTRS)

1998-01-01

This three dimensional effect is created by superimposing images of Jupiter's icy moon, Europa, which were taken from slightly different perspectives. When viewed through red (left eye) and blue (right eye) filters, this product, a stereo anaglyph, shows variations in height of surface features.

This view shows the rim and interior of the impact crater Mannann'an, on Jupiter's moon Europa. The stereo image reveals the rim of the crater which appears as a tall ridge near the left edge of the image, as well as and numerous small hills on the bottom of the crater. One of the most striking features is the large pit surrounded by circular cracks on the right side of the image, with dark radiating fractures in its center.

The right (blue) image is a high resolution image (20 meters per picture element) taken through a clear filter. The left (red) image is composed of lower resolution (80 meters per picture element) color images taken through violet, green, and near-infrared filters and averaged to approximate an unfiltered view.

North is to the top of the picture and the sun illuminates the scene from the east (right). The image, centered at 3 degrees north latitude and 120 degrees west longitude, covers an area approximately 18 by 4 kilometers (11 by 2.5 miles). The finest details that can be discerned in this picture are about 40 meters (44 yards) across. The images were taken on March 29th, 1998 at 13 hours, 17 minutes, 29 seconds Universal Time at a range of 1934 kilometers by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for

Transforming System Engineering through Model-Centric Engineering

DTIC Science & Technology

2015-01-31

story that is being applied and evolved on Jupiter Europa Orbiter (JEO) project [75], and we summarize some aspects of it here, because it goes beyond...JEO Jupiter Europa Orbiter project at NASA/JPL JSF Joint Strike Fighter JPL Jet Propulsion Laboratory of NASA Linux An operating system created by...Adaptation of Flight-Critical Systems, Digital Avionics Systems Conference, 2009. [75] Rasumussen, R., R. Shishko, Jupiter Europa Orbiter Architecture

Simulation of Na D emission near Europa during eclipse

USGS Publications Warehouse

Cassidy, T.A.; Johnson, R.E.; Geissler, P.E.; Leblanc, F.

2008-01-01

The Cassini imaging science subsystem observed Europa in eclipse during Cassini's Jupiter flyby. The disk-resolved observations revealed a spatially nonuniform emission in the wavelength range of 200-1050 nm (clear filters). By building on observations and simulations of Europa's Na atmosphere and torus we find that electron-excited Na in Europa's tenuous atmosphere can account for the observed emission if the Na is ejected preferentially from Europa's dark terrain. Copyright 2008 by the American Geophysical Union.

HST observations of Europa's atmospheric UV emission

NASA Astrophysics Data System (ADS)

Saur, J. S.; Feldman, P. D.; Strobel, D. F.; Retherford, K. D.; Roth, L.; McGrath, M. A.; Gerard, J. M.; Grodent, D. C.; Schilling, N.

2009-12-01

The Advanced Camera for Surveys on the Hubble Space Telescope observed Europa on June 29, 2008 during five consecutive orbits. Europa was at eastern elongation and crossed the Jovian current sheet during the observing interval. The observations were performed with ACS/SBC with prism PR130L to separate the two prominent FUV oxygen lines OI 1304 A, OI 1356 A and to discriminate reflected solar light from Europa's surface. After addressing the strong red leak contained in the measurements, we find that Europa's atmospheric emission clearly depends on Europa's position in Jupiter's current sheet. We also see that the atmospheric emissions of Europa's leading side do not show pronounced asymmetries with respect to Europa's sub-Jovian and anti-Jovian side. Previous observations of the atmospheric emissions, in contrast, found a strong asymmetry on Europa's trailing side [McGrath et al. 2004].

Europa Geophysical Explorer Mission Concept Studies

NASA Astrophysics Data System (ADS)

Green, J. R.; Abelson, R. D.; Smythe, W.; Spilker, T. R.; Shirley, J. H.

2005-12-01

The Strategic Road Map for Solar System Exploration recommended in May 2005 that NASA implement the Europa Geophysical Explorer (EGE) as a Flagship mission early in the next decade. This supported the recommendations of the National Research Council's Solar System Decadal Survey and the priorities of the Outer Planets Assessment Group (OPAG). The Europa Geophysical Explorer would: (1) Characterize tidal deformations of the surface of Europa and surface geology, to confirm the presence of a subsurface ocean; (2) Measure the three-dimensional structure and distribution of subsurface water; and (3) Determine surface composition from orbit, and potentially, prebiotic chemistry, in situ. As the next step in Europa exploration, EGE would build on previous Europa Orbiter concepts, for example, the original Europa Orbiter and the Jupiter Icy Moons Orbiter (JIMO). As well, a new set of draft Level One Requirements, provided by NASA sponsors, guided the concept development. These requirements included: (1) Earliest Launch: 2012; (2) Launch Vehicle: Delta IV Heavy or Atlas V; (3) Primary Propulsion: Chemical; (4) Power: Radioisotope Power System (RPS); (4) Orbital Mission: 30 days minimum to meet orbital science objectives; and (5) Earth Gravity Assists: Allowed. The previous studies and the new requirements contributed to the development of several scientifically capable and relatively mass-rich mission options. In particular, Earth-gravity assists (EGA) were allowed, resulting in an increased delivered mass. As well, there have been advances in radiation-hardened components and subsystems, due to the investments from the X-2000 technology program and JIMO. Finally, developments in radioisotope power systems (RPS) have added to the capability and reliability of the mission. Several potential mission options were explored using a variety of trade study methods, ranging from the work of the JPL EGE Team of scientists and engineers in partnership with the OPAG Europa Sub

Galileo NIMS Observations of Europa

NASA Astrophysics Data System (ADS)

Shirley, J. H.; Ocampo, A. C.; Carlson, R. W.

2000-10-01

The Galileo spacecraft began its tour of the Jovian system in December, 1995. The Galileo Millenium Mission (GMM) is scheduled to end in January, 2003. The opportunities to observe Europa in the remaining orbits are severely limited. Thus the catalog of NIMS observations of Europa is virtually complete. We summarize and describe this extraordinary dataset, which consists of 77 observations. The observations may be grouped in three categories, based on the scale of the data (km/pixel). The highest-resolution observations, with projected scales of 1-9 km/pixel, comprise one important subset of the catalog. These 29 observations sample both leading and trailing hemispheres at low and high latitudes. They have been employed in studies exploring the chemical composition of the non-ice surface materials on Europa (McCord et al., 1999, JGR 104, 11,827; Carlson et al., 1999, Science 286, 97). A second category consists of regional observations at moderate resolution. These 15 observations image Europa's surface at scales of 15-50 km/pixel, appropriate for construction of regional and global mosaics. A gap in coverage for longitudes 270-359 W may be partially filled during the 34th orbit of GMM. The final category consists of 33 global observations with scales ranging upward from 150 km/pixel. The noise levels are typically much reduced in comparison to observations taken deep within Jupiter's magnetosphere. Distant observations obtained during the 11th orbit revealed the presence of hydrogen peroxide on Europa's surface (Carlson et al., 1999b, Science 283, 2062). NIMS observations are archived in ISIS-format "cubes," which are available to researchers through the Planetary Data System (http://www-pdsimage.jpl.nasa.gov/PDS/Public/Atlas/Atlas.html). Detailed guides to every NIMS observation may be downloaded from the NIMS web site (http://jumpy.igpp.ucla.edu/ nims/).

Europa Ridges, Hills and Domes

NASA Technical Reports Server (NTRS)

1997-01-01

This moderate-resolution view of the surface of one of Jupiter's moons, Europa, shows the complex icy crust that has been extensively modified by fracturing and the formation of ridges. The ridge systems superficially resemble highway networks with overpasses, interchanges and junctions. From the relative position of the overlaps, it is possible to determine the age sequence for the ridge sets. For example, while the 8-kilometer-wide (5-mile) ridge set in the lower left corner is younger than most of the terrain seen in this picture, a narrow band cuts across the set toward the bottom of the picture, indicating that the band formed later. In turn, this band is cut by the narrow 2- kilometer-wide (1.2-mile) double ridge running from the lower right to upper left corner of the picture. Also visible are numerous clusters of hills and low domes as large as 9 kilometers (5.5 miles) across, many with associated dark patches of non-ice material. The ridges, hills and domes are considered to be ice-rich material derived from the subsurface. These are some of the youngest features seen on the surface of Europa and could represent geologically young eruptions.

This area covers about 140 kilometers by 130 kilometers (87 miles by 81 miles) and is centered at 12.3 degrees north latitude, 268 degrees west longitude. Illumination is from the east (right side of picture). The resolution is about 180 meters (200 yards) per pixel, meaning that the smallest feature visible is about a city block in size. The picture was taken by the Solid State Imaging system on board the Galileo spacecraft on February 20, 1997, from a distance of 17,700 kilometers (11,000 miles) during its sixth orbit around Jupiter.

The Jet Propulsion Laboratory, Pasadena, CA, manages the mission for NASA's Office of Space Science, Washington D.C. This image and other images and data received from Galileo are posted on the World Wide Web Galileo mission home page at http://galileo.jpl.nasa.gov.

UV Reflectance of Jupiter's Moon Europa and Asteroid (16) Psyche

NASA Astrophysics Data System (ADS)

Becker, T. M.; Retherford, K. D.; Roth, L.; Hendrix, A.; McGrath, M. A.; Cunningham, N.; Feaga, L. M.; Saur, J.; Elkins-Tanton, L. T.; Walhund, J. E.; Molyneux, P.

2017-12-01

Surface reflectance observations of solar system objects in the UV are not only complimentary to longer wavelength observations for identifying surface composition, but can also reveal new and meaningful information about the surfaces of those bodies. On Europa, far-UV (FUV) spectral observations made by the Hubble Space Telescope (HST) show that the surface lacks a strong water ice absorption edge near 165 nm, which is intriguing because such a band has been detected on most icy satellites. This may suggest that radiolytic processing by Jupiter's magnetosphere has altered the surface, causing absorption at wavelengths longward of the H2O edge, masking this feature. Additionally, the FUV spectra are blue (increasing albedo with shorter wavelengths), and regions that are observed to be dark in the visible appear bright in the FUV. This spectral inversion, also observed on the Moon and some asteroids, may provide insight into the properties of the surface material and how they are processed.We also explore the UV reflectance spectra of the main belt asteroid (16) Psyche. This asteroid is believed to be the metallic remnant core of a differentiated asteroid, stripped of its mantle through collisions. However, there is speculation that the asteroid could have formed as-is from highly reduced metal-rich material near the Sun early in the formation of the solar system. Further, spectral observations in the infrared have revealed pyroxene and hydroxyl on the asteroid's surface, complicating the interpretation that (16) Psyche is a pure metallic object. Laboratory studies indicate that there are diagnostic spectral features in the UV that could be useful for determining the surface composition. We obtained HST observations of Psyche from 160 - 300 nm. Preliminary results show a featureless, red-sloped spectrum, inconsistent with significant amounts of pyroxene on the surface. We will present the spectra of Europa and the asteroid (16) Psyche and discuss the unique details

A Power Conversion Concept for the Jupiter Icy Moons Orbiter

NASA Technical Reports Server (NTRS)

Mason, Lee S.

2003-01-01

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

DETECTION OF A HYDROGEN CORONA IN HST Ly α IMAGES OF EUROPA IN TRANSIT OF JUPITER

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

Roth, Lorenz; Ivchenko, Nickolay; Schlatter, Nicola

We report far-ultraviolet observations of Europa in transit of Jupiter obtained with the Space Telescope Imaging Spectrograph of the Hubble Space Telescope on six occasions between 2014 December and 2015 March. Absorption of Jupiter’s bright hydrogen Ly α dayglow is detected in a region several moon radii above the limb in all observations. The observed extended absorption provides the first detection of an atomic hydrogen corona around Europa. Molecular constituents in Europa’s global sputtered atmosphere are shown to be optically thin to Ly α . The observations are consistent with a radially escaping H corona with maximum densities at themore » surface in the range of (1.5–2.2) × 10{sup 3} cm{sup −3}, confirming the abundances predicted by Monte Carlo simulations. In addition, we search for anomalies around the limb of Europa from absorption by localized high H{sub 2}O abundances from active plumes. No significant local absorption features are detected. We find that an H{sub 2}O plume with line-of-sight column density in the order of 10{sup 16} cm{sup −2}, as inferred by Roth et al. would not be detectable based on the statistical fluctuations of the transit measurements, and hence is not excluded or further constrained. The presence of plumes with line-of-sight column densities of >2 × 10{sup 17} cm{sup −2} can be excluded at a 3- σ level during five of our six observations.« less

Ocean Compositions on Europa and Ganymede

NASA Astrophysics Data System (ADS)

Leitner, M. A.; Bothamy, N.; Choukroun, M.; Pappalardo, R. T.; Vance, S.

2014-12-01

The ocean compositions of icy Galilean satellites Europa and Ganymede are highly uncertain. Spectral observations of the satellites' surfaces provide clues for the interior composition. Putative sulfate hydration features in Galileo near-infrared reflectance spectra suggest fractionation of Na and Mg sulfates from a subsurface reservoir (McCord et al. 1998, Sci. 278, 271; McCord et al. 1998, Sci. 280, 1242; Dalton et al. 2005, Icarus, 177, 472). Recent spatially resolved spectral mapping of Europa hints at possible partitioning of near-surface brines in Europa's low-lying planes (Shirley et al. 2010; Icarus, 210, 358; Dalton et al. 2012; J. Geophys. Res. 117, E03003). Surface materials can be modified by the delivery of material from impacts and Io's active volcanoes as well as intense irradiation from Jupiter's magnetic field interaction with the jovian magnetosphere. These factors, combined with observations of high Cl/K ratios in Europa's exosphere, have led other investigators to suggest that Europa's ocean is dominated by dissolved chloride rather than sulfate (Brown and Hand 2013; Astr. J. 145, 110). There is still much uncertainty regarding how well the surface composition approximates the interior ocean composition. Exogenic materials, seafloor hydrothermal processes, and fractional crystallization during ice formation will determine the abundances of species in the ocean and by extension those present on Europa's surface. We develop a bottom-up model for oceans on Europa and Ganymede, assuming initial compositions of chondritic and cometary materials including an Fe core for Europa and an Fe-FeS eutectic core for Ganymede. We calculate an ocean composition by employing a Bulk Silicate Earth approach, also used by Zolotov and Shock (2001; J. Geophys. Res. 106, 32815) at Europa, which assess element partitioning between the rocky mantle, Fe-rich core, and water ocean. Partitioning factors are based on terrestrial estimates for Earth. The resulting ocean

The Europa Ocean Discovery mission

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

Edwards, B.C.; Chyba, C.F.; Abshire, J.B.

1997-06-01

Since it was first proposed that tidal heating of Europa by Jupiter might lead to liquid water oceans below Europa`s ice cover, there has been speculation over the possible exobiological implications of such an ocean. Liquid water is the essential ingredient for life as it is known, and the existence of a second water ocean in the Solar System would be of paramount importance for seeking the origin and existence of life beyond Earth. The authors present here a Discovery-class mission concept (Europa Ocean Discovery) to determine the existence of a liquid water ocean on Europa and to characterize Europa`smore » surface structure. The technical goal of the Europa Ocean Discovery mission is to study Europa with an orbiting spacecraft. This goal is challenging but entirely feasible within the Discovery envelope. There are four key challenges: entering Europan orbit, generating power, surviving long enough in the radiation environment to return valuable science, and complete the mission within the Discovery program`s launch vehicle and budget constraints. The authors will present here a viable mission that meets these challenges.« less

Europa Plumes Located near Warm Spot on Europa

NASA Image and Video Library

2017-04-13

These images of the surface of the Jovian moon Europa, taken by NASA's Galileo spacecraft, focus on a "region of interest" on the icy moon. The image at left traces the location of the erupting plumes of material, observed by NASA's Hubble Space Telescope in 2014 and again in 2016. The plumes are located inside the area surrounded by the green oval. The green oval also corresponds to a warm region on Europa's surface, as identified by the temperature map at right. The map is based on observations by the Galileo spacecraft. The warmest area is colored bright red. Researchers speculate these data offer circumstantial evidence for unusual activity that may be related to a subsurface ocean on Europa. The dark circle just below center in both images is a crater and is not thought to be related to the warm spot or the plume activity. https://photojournal.jpl.nasa.gov/catalog/PIA21444

New Radiation Zones on Jupiter

NASA Image and Video Library

2017-12-11

This graphic shows a new radiation zone surrounding Jupiter, located just above the atmosphere near the equator, that has been discovered by NASA's Juno mission. The new radiation zone is depicted here as a glowing blue area around the planet's middle. This radiation zone includes energetic hydrogen, oxygen and sulfur ions moving at close to the speed of light (referred to as "relativistic" speeds). It resides inside Jupiter's previously known radiation belts. The zone was identified by the mission's Jupiter Energetic Particle Detector Instrument (JEDI), enabled by Juno's unique close approach to the planet during the spacecraft's science flybys (2,100 miles or 3,400 kilometers from the cloud tops). Juno scientists believe the particles creating this region of intense radiation are derived from energetic neutral atoms -- that is, fast-moving atoms without an electric charge -- coming from the tenuous gas around Jupiter's moons Io and Europa. The neutral atoms then become ions -- atoms with an electric charge -- as their electrons are stripped away by interaction with the planet's upper atmosphere. (This discovery is discussed further in an issue of the journal Geophysical Research Letters [Kollmann et al. (2017), Geophys. Res. Lett., 44, 5259-5268].) Juno also has detected signatures of a population of high-energy, heavy ions in the inner edges of Jupiter's relativistic electron radiation belt. This radiation belt was previously understood to contain mostly electrons moving at near light speed. The signatures of the heavy ions are observed at high latitude locations within the electron belt -- a region not previously explored by spacecraft. The origin and exact species of these heavy ions is not yet understood. Juno's Stellar Reference Unit (SRU-1) star camera detects the signatures of this population as extremely high noise in images collected as part of the mission's radiation monitoring investigation. The locations where the heavy ions were detected are

Dissipation in the deep interiors of Ganymede and Europa

NASA Astrophysics Data System (ADS)

Hussmann, Hauke; Shoji, Daigo; Steinbruegge, Gregor; Stark, Alexander; Sohl, Frank

2017-04-01

deep interiors if the viscosities of the deeper layers are small (the phase-lag difference is almost independent of the dissipation in the surface layer). In case of Ganymede, phase-lag differences can reach values of a few degrees for high-pressure ice viscosities of 1e13-1e14 Pa s (around the lower boundary at its melting temperature) and would indicate a highly dissipative state of the deep interior. In this case, in contrast to the phase lags itself, the phase-lag difference is dominated by dissipation in the high-pressure ice layer rather than dissipation within the ice-I shell. These phase lags would be detectable from spacecraft in orbit around the satellite [3]. For Europa the phase-lag difference could reach values exceeding 20 deg if the silicate mantle contains melt and phase-lag measurements could help distinguish between (1) a hot dissipative (melt-containing) silicate mantle which would in thermal equilibrium correspond to a very thin outer ice-I shell and (2) a cold deep interior implying that dissipation would mainly occur in a thick (several tens of km) outer ice-I shell. These measurements are highly relevant for ESA's Jupiter Icy Moons Explorer (JUICE) and NASA's Europa Multiple Flyby Mission, both targeted for the Jupiter system. References: [1] Schubert, G., F. Sohl and H. Hussmann 2009. Interior of Europa. In: Europa, (R.T. Pappalardo, W.B. McKinnon, K. Khurana, Eds.), University of Arizona Press, pp. 353 - 368. [2] Schubert G., J. D. Anderson, T. Spohn, and W. B. McKinnon 2004. Interior composition, structure, and dynamics of the Galilean satellites. In: F. Bagenal, T. E. Dowling, and W. B. McKinnon (eds.) Jupiter. The Planet, Satellites, and Magnetosphere, pp. 281-306. Cambridge University Press. [3] Hussmann, H., D. Shoji, G. Steinbrügge, A. Stark, F. Sohl 2016. Constraints on dissipation in the deep interiors of Ganymede and Europa from tidal phase-lags. Cel. Mech. Dyn. Astr. 126, 131 - 144.

Planetary science. Europa's ocean--the case strengthens.

PubMed

Stevenson, D

2000-08-25

The possibility of a subsurface ocean on Jupiter's moon Europa has been suggested on the basis of theoretical, geological, and spectroscopic arguments. But, as Stevenson explains in his Perspective, none of these arguments were compelling. In contrast, the magnetic field data obtained by the Galileo spacecraft and presented in the report by Kivelson et al., provide persuasive evidence for a conducting layer--most likely a global water ocean--near Europa's surface.

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.

Europa: Prospects for an ocean and exobiological implications

NASA Technical Reports Server (NTRS)

Oro, John; Squyres, Steven W.; Reynolds, Ray T.; Mills, Thomas M.

1992-01-01

As far as we know, Earth is the only planet in our solar system that supports life. It is natural, therefore, that our understanding of life as a planetary phenomenon is based upon Earth-like planets. There are environments in the solar system where liquid water, commonly believed to be a prerequisite for biological activity, may exist in a distinctly non-Earth-like environment. One such location is Europa, one of the Galilean satellites of Jupiter. The possibility that liquid water exists on Europa presents us with some interesting exobiological implications concerning the potential of the satellite to support life. Topics include the following: an ocean on Europa; thermal evolution of Europa; Europa's three models; exobiological implications; early conditions of Europa; low-temperature abiotic chemistry; possibility of the emergence of life on Europa; prerequisites for the habitability of Europa; energy sources for biosynthesis and metabolic activity; habitability of Europa by anaerobic life; and habitability by aerobic life.

Tidal dissipiation in Europa - A correction

NASA Technical Reports Server (NTRS)

Cassen, P.; Reynolds, R. T.; Peale, S. J.

1980-01-01

The possibility that tidal dissipation in a thin ice crust was sufficient to preserve liquid water on Jupiter's satellite Europa was suggested by Cassen et al. (1979). However, their calculation of the tidal heating rate for that situation is in error; for the same parameter values, the actual heating rate would be much less than given in their paper. Thus, their conclusion regarding the possibility that liquid water exists today on Europa is considerably weakened. This paper corrects the calculation of the tidal dissipation rate in a Europan ice crust, and discusses the implications for Europa's thermal history, and clarifies certain aspects of the tidal heating problem.

Europa Explorer Operational Scenarios Development

NASA Technical Reports Server (NTRS)

Lock, Robert E.; Pappalardo, Robert T.; Clark, Karla B.

2008-01-01

In 2007, NASA conducted four advanced mission concept studies for outer planets targets: Europa, Ganymede, Titan and Enceladus. The studies were conducted in close cooperation with the planetary science community. Of the four, the Europa Explorer Concept Study focused on refining mission options, science trades and implementation details for a potential flagship mission to Europa in the 2015 timeframe. A science definition team (SDT) was appointed by NASA to guide the study. A JPL-led engineering team worked closely with the science team to address 3 major focus areas: 1) credible cost estimates, 2) rationale and logical discussion of radiation risk and mitigation approaches, and 3) better definition and exploration of science operational scenario trade space. This paper will address the methods and results of the collaborative process used to develop Europa Explorer operations scenarios. Working in concert with the SDT, and in parallel with the SDT's development of a science value matrix, key mission capabilities and constraints were challenged by the science and engineering members of the team. Science goals were advanced and options were considered for observation scenarios. Data collection and return strategies were tested via simulation, and mission performance was estimated and balanced with flight and ground system resources and science priorities. The key to this successful collaboration was a concurrent development environment in which all stakeholders could rapidly assess the feasibility of strategies for their success in the full system context. Issues of science and instrument compatibility, system constraints, and mission opportunities were treated analytically and objectively leading to complementary strategies for observation and data return. Current plans are that this approach, as part of the system engineering process, will continue as the Europa Explorer Concept Study moves toward becoming a development project.

A Radiation Hard Multi-Channel Digitizer ASIC for Operation in the Harsh Jovian Environment

NASA Technical Reports Server (NTRS)

Aslam, Shahid; Aslam, S.; Akturk, A.; Quilligan, G.

2011-01-01

In 1995, the Galileo spacecraft arrived at Jupiter to conduct follow-up experiments on pathfinder Pioneer and key Voyager discoveries especially at Io, Europa, Ganymede and Callisto. These new observations helped expand our scientific knowledge of the prominent Galilean satellites; studies revealed diversity with respect to their geology, internal structure, evolution and degree of past and present activity. Jupiter's diverse Galilean satellites, of which three are believed to harbor internal oceans, are central to understanding the habitability of icy worlds. Galileo provided for the first time compelling evidence of a near-surface global ocean on Europa. Furthermore, by understanding the Jupiter system and unraveling the history of its evolution from initial formation to the emergence of possible habitats and life, gives insight into how giant planets and their satellite systems form and evolve. Most important, new light is shed on the potential for the emergence and existence of life in icy satellite oceans. In 2009, NASA released a detailed Jupiter Europa Mission Study (EJSM) that proposed an ambitious Flagship Mission to understand more fully the satellites Europa and Ganymede within the context of the Jovian system. Key to EJSM is the NASA led Jupiter Europa Orbiter (JEO) and the ESA led Jupiter Ganymede Orbiter (JGO). JEO and JGO would execute a choreographed exploration of the Jovian system before settling into orbit around Europa and Ganymede, respectively. The National Academies Planetary Decadal Survey, 2011 has listed the NASA-led JEO as the second highest priority mission for the decade 2013-2022, and if chosen it would be launched in 2020 with arrival at Jupiter in 2025. If the JEO mission is not chosen it is anticipated that there will be opportunities in future decadal cycles. Jupiter Orbit Insertion (JOI) begins a 30-month Jovian system tour followed by nine months of science mapping after Europa Orbit Insertion (EOI) in July 2028. The orbiter will

Modeling Europa's Ice-Ocean Interface

NASA Astrophysics Data System (ADS)

Elsenousy, A.; Vance, S.; Bills, B. G.

2014-12-01

This work focuses on modeling the ice-ocean interface on Jupiter's Moon (Europa); mainly from the standpoint of heat and salt transfer relationship with emphasis on the basal ice growth rate and its implications to Europa's tidal response. Modeling the heat and salt flux at Europa's ice/ocean interface is necessary to understand the dynamics of Europa's ocean and its interaction with the upper ice shell as well as the history of active turbulence at this area. To achieve this goal, we used McPhee et al., 2008 parameterizations on Earth's ice/ocean interface that was developed to meet Europa's ocean dynamics. We varied one parameter at a time to test its influence on both; "h" the basal ice growth rate and on "R" the double diffusion tendency strength. The double diffusion tendency "R" was calculated as the ratio between the interface heat exchange coefficient αh to the interface salt exchange coefficient αs. Our preliminary results showed a strong double diffusion tendency R ~200 at Europa's ice-ocean interface for plausible changes in the heat flux due to onset or elimination of a hydrothermal activity, suggesting supercooling and a strong tendency for forming frazil ice.

Sounding of Europa's interior using multi-frequency electromagnetic induction from a Europa orbiter

NASA Astrophysics Data System (ADS)

Khurana, K. K.; Kivelson, M. G.; Russell, C. T.

2000-12-01

Magnetic field observations from Galileo have shown that Europa induces a strong response to the varying field of Jupiter's magnetosphere. These observations are consistent with a global conductor located close to the surface. Khurana et al. [1998] and Kivelson et al. [1999] have shown that a moon-wide ocean with a conductivity similar to the Earth's ocean and having a thickness of at least 6 km could produce the observed induction signature. Many other geological and geophysical observations are consistent with this interpretation (See Pappalardo et al. [1999] for further details.). The magnetic induction signature at a single frequency can also be explained with a model in which the conducting layer is thinner (thicker) but has higher (lower) conductivity. The initial work relied on the variations of the time varying field at the synodic rotation period of Jupiter (as seen in the rest frame of the moon) to infer the interior structure of Europa. We have extended the initial analysis by showing that the spectrum of the primary field contains several other important frequencies. We single out one frequency-corresponding to the orbital period of Europa-for further examination. We show that by modeling the induction response at this frequency in addition to the previously used synodic frequency for a range of ocean shell thicknesses and conductivities, the ocean conductivity and the thickness of the ocean at Europa can be determined uniquely. We discuss how the measurements from an orbiting spacecraft can be decomposed into the internal (which is the secondary field) and external (the primary imposed field) components not only for the steady field but also for the varying field.

Jupiter's Mid-Infrared Aurora: Solar Connection and Minor Constituents

NASA Technical Reports Server (NTRS)

Kostiuk, Theodore; Livengood, T.A.; Fast, K.E.; Hewagama, T.; Schmilling, F.; Sonnabend, G.; Delgado, J.

2009-01-01

High spectral resolution in the 12 pin region of the polar regions of Jupiter reveal unique information on auroral phenomena and upper stratospheric composition. Polar aurorae in Jupiter's atmosphere radiate; throughout the electromagnetic spectrum from X-ray through mid-infrared (mid-IR, 5 - 20 micron wavelength). Voyager IRIS data and ground-based. spectroscopic measurements of Jupiter's northern mid-IR aurora acquired since 1982, reveal a correlation between auroral brightness and solar activity that has not been observed in Jovian aurora at other wavelengths. Over nearly three solar cycles, Jupiter auroral ethane, emission brightness and solar 10.7-cm radar flux and sunspot number are positively correlated with high confidence. Ethane line emission intensity varies over tenfold between low and high scalar activity periods. Detailed measurements have been made using the GSFC HIPWAC spectrometer at the NASA IRTF since the last solar maximum, following the mid-IR emission through the declining phase toward solar minimum. An even more convincing correlation with solar activity is evident in these data. The spectra measured contain features that cannot be attributed to ethane and are most likely spectra of minor constituents whose molecular bands overlap the v9 band of ethane. Possible candidates are allene, propane, and other higher order hydrocarbons. These features appear to be enhanced in the active polar regions. Laboratory measurements at comparable spectral resolution of spectra of candidate molecules will be used to identify the constituents. Current analyses of these results will be described, including planned measurements on polar ethane line emission scheduled through the rise of the next solar maximum beginning in 2009, with a steep gradient to a maximum in 2012. This work is relevant to the Juno mission and to the development of the NASA/ESA Europa Jupiter System Mission.

High-Resolution Image of Europa's Ridged Plains

NASA Technical Reports Server (NTRS)

1998-01-01

This spectacular image taken by NASA's Galileo spacecraft camera shows a region of ridged plains on Jupiter's moon Europa. The plains are comprised of many parallel and cross-cutting ridges, commonly in pairs. The majority of the region is of very bright, but darker material is seen primarily in valleys between ridges. Some of the most prominent ridges have dark deposits along their margins and in their central valleys. Some of this dark material probably moved down the flanks of the ridges and has piled up along their bases. The most prominent ridges are about a kilometer in width (less than a mile). In the top right hand corner of the image the end of a dark wide ridge (about 2 kilometers or 1.2 miles across) is visible. Several deep fractures cut through this ridge and continue into the plains. The brightness of the region suggests that frost covers much of Europa's surface. This image looks different from those obtained earlier in Galileo's mission, because this image was taken with the Sun higher in Europa's sky.

This image was taken on December 16, 1997 at a range of 1,300 kilometers (800 miles) by Galileo's solid state imaging system. North is to the top of the picture, and the Sun illuminates the surface from the upper left. This image, centered at approximately 14 degrees south latitude and 194 degrees west longitude, covers an area approximately 20 kilometers (12 miles) on each side. The resolution is 26 meters (85 feet) per picture element.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

Evidence of Plumes on Europa from far-ultraviolet observations with HST

NASA Astrophysics Data System (ADS)

Sparks, William B.; McGrath, Melissa; Schmidt, Britney; Bergeron, Eddie; Hand, Kevin; Spencer, John; Cracraft, Misty; Deustua, Susana

2018-01-01

Evidence for plumes of water emerging from the icy surface of Europa has been found by the Hubble Space Telescope (HST) using two different UV observing techniques. Roth et al. (2014) found line emission from the dissociation products of water. Sparks et al. (2016, 2017) found evidence for off-limb continuum absorption as Europa transited Jupiter. We describe the transit method which obtains far ultraviolet images of Europa as it passes in front of the smooth face of Jupiter, seeking off-limb absorption patches that may be due to plumes on Europa. This approach exploits the time resolution, sensitivity and spatial resolution of HST, coupled to the high cross-sections for molecules of interest at these wavelengths. We show that a well-localized plume candidate appears more than once, and that it is at the same position as a nighttime thermal anomaly seen by the Galileo spacecraft, the warmest point on the observed Europa nightside. The favored interpretation of the thermal anomaly is a modification to the local thermal inertia, which could be causally related to plume activity. Future plans for additional work in this area are described.

Galileo's First Images of Jupiter and the Galilean Satellites

PubMed

Belton, M J S; Head, J W; Ingersoll, A P; Greeley, R; McEwen, A S; Klaasen, K P; Senske, D; Pappalardo, R; Collins, G; Vasavada, A R; Sullivan, R; Simonelli, D; Geissler, P; Carr, M H; Davies, M E; Veverka, J; Gierasch, P J; Banfield, D; Bell, M; Chapman, C R; Anger, C; Greenberg, R; Neukum, G; Pilcher, C B; Beebe, R F; Burns, J A; Fanale, F; Ip, W; Johnson, T V; Morrison, D; Moore, J; Orton, G S; Thomas, P; West, R A

1996-10-18

The first images of Jupiter, Io, Europa, and Ganymede from the Galileo spacecraft reveal new information about Jupiter's Great Red Spot (GRS) and the surfaces of the Galilean satellites. Features similar to clusters of thunderstorms were found in the GRS. Nearby wave structures suggest that the GRS may be a shallow atmospheric feature. Changes in surface color and plume distribution indicate differences in resurfacing processes near hot spots on Io. Patchy emissions were seen while Io was in eclipse by Jupiter. The outer margins of prominent linear markings (triple bands) on Europa are diffuse, suggesting that material has been vented from fractures. Numerous small circular craters indicate localized areas of relatively old surface. Pervasive brittle deformation of an ice layer appears to have formed grooves on Ganymede. Dark terrain unexpectedly shows distinctive albedo variations to the limit of resolution.

Galileo's first images of Jupiter and the Galilean satellites

USGS Publications Warehouse

Belton, M.J.S.; Head, J. W.; Ingersoll, A.P.; Greeley, R.; McEwen, A.S.; Klaasen, K.P.; Senske, D.; Pappalardo, R.; Collins, G.; Vasavada, A.R.; Sullivan, R.; Simonelli, D.; Geissler, P.; Carr, M.H.; Davies, M.E.; Veverka, J.; Gierasch, P.J.; Banfield, D.; Bell, M.; Chapman, C.R.; Anger, C.; Greenberg, R.; Neukum, G.; Pilcher, C.B.; Beebe, R.F.; Burns, J.A.; Fanale, F.; Ip, W.; Johnson, T.V.; Morrison, D.; Moore, J.; Orton, G.S.; Thomas, P.; West, R.A.

1996-01-01

The first images of Jupiter, Io, Europa, and Ganymede from the Galileo spacecraft reveal new information about Jupiter's Great Red Spot (GRS) and the surfaces of the Galilean satellites. Features similar to clusters of thunderstorms were found in the GRS. Nearby wave structures suggest that the GRS may be a shallow atmospheric feature. Changes in surface color and plume distribution indicate differences in resurfacing processes near hot spots on lo. Patchy emissions were seen while Io was in eclipse by Jupiter. The outer margins of prominent linear markings (triple bands) on Europa are diffuse, suggesting that material has been vented from fractures. Numerous small circular craters indicate localized areas of relatively old surface. Pervasive brittle deformation of an ice layer appears to have formed grooves on Ganymede. Dark terrain unexpectedly shows distinctive albedo variations to the limit of resolution.

Oceans, Ice Shells, and Life on Europa

NASA Technical Reports Server (NTRS)

Schenk, Paul

2002-01-01

The four large satellites of Jupiter are famous for their planet-like diversity and complexity, but none more so than ice-covered Europa. Since the provocative Voyager images of Europa in 1979, evidence has been mounting that a vast liquid water ocean may lurk beneath the moon's icy surface. Europa has since been the target of increasing and sometimes reckless speculation regarding the possibility that giant squid and other creatures may be swimming its purported cold, dark ocean. No wonder Europa tops everyone's list for future exploration in the outer solar system (after the very first reconnaissance of Pluto and the Kuiper belt, of course). Europa may be the smallest of the Galilean moons (so-called because they were discovered by Galileo Galilei in the early 17th century) but more than makes up for its diminutive size with a crazed, alien landscape. The surface is covered with ridges hundreds of meters high, domes tens of kilometers across, and large areas of broken and disrupted crust called chaos. Some of the geologic features seen on Europa resemble ice rafts floating in polar seas here on Earth-reinforcing the idea that an ice shell is floating over an ocean on this Moon-size satellite. However, such features do not prove that an ocean exists or ever did. Warm ice is unusually soft and will flow under its own weight. If the ice shell is thick enough, the warm bottom of the shell will flow, as do terrestrial glaciers. This could produce all the observed surface features on Europa through a variety of processes, the most important of which is convection. (Convection is the vertical overturn of a layer due to heating or density differences-think of porridge or sauce boiling on the stove.) Rising blobs from the base of the crust would then create the oval domes dotting Europa's surface. The strongest evidence for a hidden ocean beneath Europa's surface comes from the Galileo spacecraft's onboard magnetometer, which detected fluctuations in Jupiter's magnetic

Folds on Europa: implications for crustal cycling and accommodation of extension.

PubMed

Prockter, L M; Pappalardo, R T

2000-08-11

Regional-scale undulations with associated small-scale secondary structures are inferred to be folds on Jupiter's moon Europa. Formation is consistent with stresses from tidal deformation, potentially triggering compressional instability of a region of locally high thermal gradient. Folds may compensate for extension elsewhere on Europa and then relax away over time.

New Observations of UV Emissions from Europa

NASA Technical Reports Server (NTRS)

McGrath, Melissa; Sparks, William

2009-01-01

The recent top prioritization of the Europa Jupiter System Mission for the next outer solar system flagship mission is refocusing attention on Europa and the other Galilean satellites and their contextual environments in the Jupiter system. Surface sputtering by magnetospheric plasma generates a tenuous atmosphere for Europa, dominated by 02 gas. This tenuous gas is in turn excited by plasma electrons, producing ultraviolet and visible emissions. Two sets of imaging observations have been published to date, UV images from the Hubble Space Telescope, and visible eclipse images from Cassini. Three additional sets of HST UV observations were acquired in February 2007, April 2007 and June 2009. The signal to noise ratio in these data are not high, however, given the paucity of data and its increasing importance in terms of planning for EJSM, we have attempted to extract as much new information as possible from these data. This talk will summarize our analysis to date, and discuss them in terms of existing models, which attempt to explain the image morphology either in terms of the underlying source production and loss processes, or in terms of the plasma interaction with the exosphere.

Jupiter Wave

NASA Image and Video Library

2015-10-13

Scientists spotted a rare wave in Jupiter North Equatorial Belt that had been seen there only once before in this false-color close-up from NASA Hubble Telescope. In Jupiter's North Equatorial Belt, scientists spotted a rare wave that had been seen there only once before. It is similar to a wave that sometimes occurs in Earth's atmosphere when cyclones are forming. This false-color close-up of Jupiter shows cyclones (arrows) and the wave (vertical lines). http://photojournal.jpl.nasa.gov/catalog/PIA19659

Water Vapor Over Europa

NASA Image and Video Library

2013-12-12

This graphic shows the location of water vapor detected over Europa south pole in observations taken by NASA Hubble Space Telescope in December 2012. This is the first strong evidence of water plumes erupting off Europa surface.

Formation of cycloidal features on Europa.

PubMed

Hoppa, G V; Tufts, B R; Greenberg, R; Geissler, P E

1999-09-17

Cycloidal patterns are widely distributed on the surface of Jupiter's moon Europa. Tensile cracks may have developed such a pattern in response to diurnal variations in tidal stress in Europa's outer ice shell. When the tensile strength of the ice is reached, a crack may occur. Propagating cracks would move across an ever-changing stress field, following a curving path to a place and time where the tensile stress was insufficient to continue the propagation. A few hours later, when the stress at the end of the crack again exceeded the strength, propagation would continue in a new direction. Thus, one arcuate segment of the cycloidal chain would be produced during each day on Europa. For this model to work, the tensile strength of Europa's ice crust must be less than 40 kilopascals, and there must be a thick fluid layer below the ice to allow sufficient tidal amplitude.

Dark Bands on Europa

NASA Technical Reports Server (NTRS)

1996-01-01

Dark crisscrossing bands on Jupiter's moon Europa represent widespread disruption from fracturing and the possible eruption of gases and rocky material from the moon's interior in this four-frame mosaic of images from NASA's Galileo spacecraft. These and other features suggest that soft ice or liquid water was present below the ice crust at the time of disruption. The data do not rule out the possibility that such conditions exist on Europa today. The pictures were taken from a distance of 156,000 kilometers (about 96,300 miles) on June 27, 1996. Many of the dark bands are more than 1,600 kilometers (1,000 miles) long, exceeding the length of the San Andreas fault of California. Some of the features seen on the mosaic resulted from meteoritic impact, including a 30- kilometer (18.5 mile) diameter crater visible as a bright scar in the lower third of the picture. In addition, dozens of shallow craters seen in some terrains along the sunset terminator zone (upper right shadowed area of the image) are probably impact craters. Other areas along the terminator lack craters, indicating relatively youthful surfaces, suggestive of recent eruptions of icy slush from the interior. The lower quarter of the mosaic includes highly fractured terrain where the icy crust has been broken into slabs as large as 30 kilometers (18.5 miles) across. The mosaic covers a large part of the northern hemisphere and includes the north pole at the top of the image. The sun illuminates the surface from the left. The area shown is centered on 20 degrees north latitude and 220 degrees west longitude and is about as wide as the United States west of the Mississippi River. The Galileo mission is managed by NASA's Jet Propulsion Laboratory.

An Overview of the Exploration History of Europa

NASA Astrophysics Data System (ADS)

Alexander, C. J.; Consolmagno, G.; Greeley, R.; Morrison, D.

2007-12-01

Twenty-four years ago, a Nature paper announced the results of study of the Voyager images of the Jovian moon Europa, in which linear fracture-like markings were projected to be evidence of liquid water and active resurfacing [Nature 301, 225 - 226 (20 January 1983)]. This paper was a post-Voyager study that pre-dated the Galileo findings by two decades. Years of modeling had gone into the effort to understand the potential thermal history of the icy moons of Jupiter. Much of the theoretical work concluded that the bodies would have been frozen solid for billions of years, but there was enough work to suggest further in situ investigation was warranted. Behind the scenes was a concerted effort to make the Galilean satellites the focus of unmanned exploration for NASA's planetary science program. The historic significance of this journey of exploration, the manner in which it unfolded, is of relevance to a whole new generation of investigators. In this talk we will present highlights of the entire period of discovery, from the commensurate orbital motions first observed by Galileo himself [1609], that would prove critical to understanding the evolution of Europa; the theoretical work on motions of the celestial bodies by Laplace [1805] that laid the ground work for understanding the resonances; Jeans [1925] speculations about the existence of the atmospheres of the Galilean satellites in his Theory of Gases; to the ground-breaking discovery by Kuiper of the spectral signature of ice on Europa ; the work by Urey [1952] making the cosmochemical arguments about the significance of water ice in the outer solar system; efforts to understand, from photometry and spectrometry, whether surface impurities were endogenic or exogenic in origin; and the work of Johnson and colleagues laying the groundwork for the understanding of the significance of sputtering in the solar system [Johnson, et al., 1982]. We will present highlights of the exploration of the Jupiter system with

San Andreas-sized Strike-slip Fault on Europa

NASA Technical Reports Server (NTRS)

1998-01-01

This mosaic of the south polar region of Jupiter's moon Europa shows the northern 290 kilometers (180 miles) of a strike-slip fault named Astypalaea Linea. The entire fault is about 810 kilometers (500 miles) long, about the size of the California portion of the San Andreas fault, which runs from the California-Mexico border north to the San Francisco Bay.

In a strike-slip fault, two crustal blocks move horizontally past one another, similar to two opposing lanes of traffic. Overall motion along the fault seems to have followed a continuous narrow crack along the feature's entire length, with a path resembling steps on a staircase crossing zones that have been pulled apart. The images show that about 50 kilometers (30 miles) of displacement have taken place along the fault. The fault's opposite sides can be reconstructed like a puzzle, matching the shape of the sides and older, individual cracks and ridges broken by its movements.

[figure removed for brevity, see original site]

The red line marks the once active central crack of the fault. The black line outlines the fault zone, including material accumulated in the regions which have been pulled apart.

Bends in the fault have allowed the surface to be pulled apart. This process created openings through which warmer, softer ice from below Europa's brittle ice shell surface, or frozen water from a possible subsurface ocean, could reach the surface. This upwelling of material formed large areas of new ice within the boundaries of the original fault. A similar pulling-apart phenomenon can be observed in the geological trough surrounding California's Salton Sea, in Death Valley and the Dead Sea. In those cases, the pulled-apart regions can include upwelled materials, but may be filled mostly by sedimentary and eroded material from above.

One theory is that fault motion on Europa is induced by the pull of variable daily tides generated by Jupiter's gravitational tug on Europa. Tidal tension

Effects of Io ejecta on Europa

NASA Astrophysics Data System (ADS)

Eviatar, A.; Siscoe, G. L.; Johnson, T. V.; Matson, D. L.

1981-07-01

The effects of plasma ejected from Io on the nature and evolution of the surface of Europa and on the relative importance of the roles played by the two satellites in the Jupiter magnetosphere are examined. Observations of an ultraviolet absorption feature on the trailing side of Europa are interpreted as due to an equilibrium column density of SO2 in a steady-state model of the implantation of iogenic ions into the surface of Europa and their subsequent sputtering. The observed sulfur column density of 2 x 10 to the 16th/sq cm implies a slow loss of material from Europa, mainly water ice, and indicates that the spectrum of particles sputtered is soft. Considerations of the comparative roles of corotating and energetic heavy ions are shown to suggest that the implantation and sputtering is primarily the result of the proton and light ion component of the plasma. The weakness of Europa as a plasma source resulting from the soft sputtered particle spectrum thus leads to the dominance of Io in contributing to the magnetospheric plasma.

Navigational Challenges for a Europa Flyby Mission

NASA Technical Reports Server (NTRS)

Martin-Mur, Tomas J.; Ionasescu, Rodica; Valerino, Powtawche; Criddle, Kevin; Roncoli, Ralph

2014-01-01

Jupiter's moon Europa is a prime candidate in the search for present-day habitable environments outside of the Earth. A number of missions have provided increasingly detailed images of the complex surface of Europa, including the Galileo mission, which also carried instruments that allowed for a limited investigation of the environment of Europa. A new mission to Europa is needed to pursue these exciting discoveries using close-up observations with modern instrumentation designed to address the habitability of Europa. In all likelihood the most cost effective way of doing this would be with a spacecraft carrying a comprehensive suite of instruments and performing multiple flybys of Europa. A number of notional trajectory designs have been investigated, utilizing gravity assists from other Galilean moons to decrease the period of the orbit and shape it in order to provide a globally distributed coverage of different regions of Europa. Navigation analyses are being performed on these candidate trajectories to assess the total Delta V that would be needed to complete the mission, to study how accurately the flybys could be executed, and to determine which assumptions most significantly affect the performance of the navigation system.

Magnetic induction constraints on electrical conductivity within Europa

NASA Astrophysics Data System (ADS)

Bills, B. G.; Vance, S.

2017-12-01

We examine the problem of inferring radial variations in electrical conductivity within Europa, from measurements of the magnetic field induced within Europa by its motion through Jupiter's magnetic field. The Europa Clipper mission is expected to make multiple encounters with Europa, sampling several periods at which significant magnetic induction forcing occurs. Most previous analyses have considered a simple 3-layer model of Europa's internal structure, with an insulating core, a uniform conductivity ocean, and an insulating ice shell, and have only examined responses at 2 forcing periods. We attempt to address the broader issues of what level of detail can be inferred from plausible estimates of induced field response at several additional forcing periods. We will present results of an analysis of the periods and amplitudes of magnetic field variations at Europa, and at the Europa Clipper spacecraft. It appears likely that useful information on the induction response will be attained at 6 forcing frequencies, spanning the interval from 1 to just over 15 cycles per orbital period, in Europa's motion about Jupiter. The range of periods is 5.6 to 85 hours. The induced field diffuses into the interior, and signals at longer periods penetrate more deeply. Having measurements at a range of forcing periods thus helps resolve radial structure. Even if the ocean is well mixed and has uniform salinity, there will be some depth-dependent variations in electrical conductivity due to temperature and pressure variations. Much larger variations would be present if the ocean were stably stratified, with a denser brine underlying a fresher upper layer. While vigorous convection within the ocean would likely mix and homogenize the water column, a stratified ocean is at least possible. Could such a feature of the ocean be detected via magnetic induction? Also, the conductivities in the ice shell above, and silicate layer beneath the ocean are expected to be substantially smaller

Juno’s Latest Close Flyby of Jupiter on This Week @NASA – February 3, 2017

NASA Image and Video Library

2017-02-03

NASA’s Juno spacecraft made its latest close flyby of Jupiter Feb. 2 -- passing about 2,700 miles above the planet’s clouds. This was the fourth close flyby since Juno began orbiting Jupiter last year on July 4. During these close passes instruments on the spacecraft probe beneath the cloud cover to collect scientific data about the planet's structure, atmosphere and magnetosphere. This information could help us better understand the planetary systems being discovered around other stars. Also, Cassini Sees Saturn’s Rings in Greater Detail, The Most Extreme Blazars, NASA at Super Bowl Event, NASA at NBA Black Heritage Celebration, and Day of Remembrance!

Jupiter Icy Moons Orbiter Mission design overview

NASA Technical Reports Server (NTRS)

Sims, Jon A.

2006-01-01

An overview of the design of a possible mission to three large moons of Jupiter (Callisto, Ganymede, and Europa) is presented. The potential Jupiter Icy Moons Orbiter (JIMO) mission uses ion thrusters powered by a nuclear reactor to transfer from Earth to Jupiter and enter a low-altitude science orbit around each of the moons. The combination of very limited control authority and significant multibody dynamics resulted in some aspects of the trajectory design being different than for any previous mission. The results of several key trades, innovative trajectory types and design processes, and remaining issues are presented.

Europa 'Ice Rafts' in local and color context

NASA Technical Reports Server (NTRS)

1998-01-01

This image of Jupiter's icy satellite Europa shows surface features such as domes and ridges, as well as a region of disrupted terrain including crustal plates which are thought to have broken apart and 'rafted' into new positions. The image covers an area of Europa's surface about 250 by 200 kilometer (km) and is centered at 10 degrees latitude, 271 degrees longitude. The color information allows the surface to be divided into three distinct spectral units. The bright white areas are ejecta rays from the relatively young crater Pwyll, which is located about 1000 km to the south (bottom) of this image. These patchy deposits appear to be superposed on other areas of the surface, and thus are thought to be the youngest features present. Also visible are reddish areas which correspond to locations where non-ice components are present. This coloring can be seen along the ridges, in the region of disrupted terrain in the center of the image, and near the dome-like features where the surface may have been thermally altered. Thus, areas associated with internal geologic activity appear reddish. The third distinct color unit is bright blue, and corresponds to the relatively old icy plains.

This product combines data taken by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft during three separate flybys of Europa. Low resolution color data (violet, green, and 1 micron) acquired in September 1996 were combined with medium resolution images from December 1996, to produce synthetic color images. These were then combined with a high resolution mosaic of images acquired in February 1997.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa

Evidence of a plume on Europa from Galileo magnetic and plasma wave signatures

NASA Astrophysics Data System (ADS)

Jia, Xianzhe; Kivelson, Margaret G.; Khurana, Krishan K.; Kurth, William S.

2018-05-01

The icy surface of Jupiter's moon, Europa, is thought to lie on top of a global ocean1-4. Signatures in some Hubble Space Telescope images have been associated with putative water plumes rising above Europa's surface5,6, providing support for the ocean theory. However, all telescopic detections reported were made at the limit of sensitivity of the data5-7, thereby calling for a search for plume signatures in in-situ measurements. Here, we report in-situ evidence of a plume on Europa from the magnetic field and plasma wave observations acquired on Galileo's closest encounter with the moon. During this flyby, which dropped below 400 km altitude, the magnetometer8 recorded an approximately 1,000-kilometre-scale field rotation and a decrease of over 200 nT in field magnitude, and the Plasma Wave Spectrometer9 registered intense localized wave emissions indicative of a brief but substantial increase in plasma density. We show that the location, duration and variations of the magnetic field and plasma wave measurements are consistent with the interaction of Jupiter's corotating plasma with Europa if a plume with characteristics inferred from Hubble images were erupting from the region of Europa's thermal anomalies. These results provide strong independent evidence of the presence of plumes at Europa.

Evidence of a plume on Europa from Galileo magnetic and plasma wave signatures

NASA Astrophysics Data System (ADS)

Jia, Xianzhe; Kivelson, Margaret G.; Khurana, Krishan K.; Kurth, William S.

2018-06-01

The icy surface of Jupiter's moon, Europa, is thought to lie on top of a global ocean1-4. Signatures in some Hubble Space Telescope images have been associated with putative water plumes rising above Europa's surface5,6, providing support for the ocean theory. However, all telescopic detections reported were made at the limit of sensitivity of the data5-7, thereby calling for a search for plume signatures in in-situ measurements. Here, we report in-situ evidence of a plume on Europa from the magnetic field and plasma wave observations acquired on Galileo's closest encounter with the moon. During this flyby, which dropped below 400 km altitude, the magnetometer8 recorded an approximately 1,000-kilometre-scale field rotation and a decrease of over 200 nT in field magnitude, and the Plasma Wave Spectrometer9 registered intense localized wave emissions indicative of a brief but substantial increase in plasma density. We show that the location, duration and variations of the magnetic field and plasma wave measurements are consistent with the interaction of Jupiter's corotating plasma with Europa if a plume with characteristics inferred from Hubble images were erupting from the region of Europa's thermal anomalies. These results provide strong independent evidence of the presence of plumes at Europa.

Europa Global Views in Natural and Enhanced Colors

NASA Image and Video Library

1998-05-08

This color composite view combines violet, green, and infrared images of Jupiter intriguing moon, Europa, for a view of the moon in natural color left and in enhanced color designed to bring out subtle color differences in the surface right.

Jupiter Eruptions

NASA Image and Video Library

2008-01-25

NASA Hubble Space Telescope shows detailed analysis of two continent-sized storms that erupted in Jupiter atmosphere in March 2007 shows that Jupiter internal heat plays a significant role in generating atmospheric disturbances .

Strong Solar Control of Infrared Aurora on Jupiter: Correlation Since the Last Solar Maximum

NASA Technical Reports Server (NTRS)

Kostiuk, T.; Livengood, T. A.; Hewagama, T.

2009-01-01

Polar aurorae in Jupiter's atmosphere radiate throughout the electromagnetic spectrum from X ray through mid-infrared (mid-IR, 5 - 20 micron wavelength). Voyager IRIS data and ground-based spectroscopic measurements of Jupiter's northern mid-IR aurora, acquired since 1982, reveal a correlation between auroral brightness and solar activity that has not been observed in Jovian aurora at other wavelengths. Over nearly three solar cycles, Jupiter auroral ethane emission brightness and solar 10.7 cm radio flux and sunspot number are positively correlated with high confidence. Ethane line emission intensity varies over tenfold between low and high solar activity periods. Detailed measurements have been made using the GSFC HIPWAC spectrometer at the NASA IRTF since the last solar maximum, following the mid-IR emission through the declining phase toward solar minimum. An even more convincing correlation with solar activity is evident in these data. Current analyses of these results will be described, including planned measurements on polar ethane line emission scheduled through the rise of the next solar maximum beginning in 2009, with a steep gradient to a maximum in 2012. This work is relevant to the Juno mission and to the development of the Europa Jupiter System Mission. Results of observations at the Infrared Telescope Facility (IRTF) operated by the University of Hawaii under Cooperative Agreement no. NCC5-538 with the National Aeronautics and Space Administration, Science Mission Directorate, Planetary Astronomy Program. This work was supported by the NASA Planetary Astronomy Program.

Cylindrical Projection of Jupiter

NASA Image and Video Library

1996-01-29

This computer generated map of Jupiter was made from 10 color images of Jupiter taken Feb. 1, 1979, by NASA Voyager 1, during a single, 10 hour rotation of the planet. http://photojournal.jpl.nasa.gov/catalog/PIA00011

Europa Crescent

NASA Image and Video Library

1998-06-04

This archival image taken by NASA Voyager 2, is of Europa, the smallest Galilean satellite. The bright areas are probably ice deposits, whereas the darkened areas may be the rocky surface or areas with a more patchy distribution of ice. http://photojournal.jpl.nasa.gov/catalog/PIA00325

Speeding Towards Jupiter Pole

NASA Image and Video Library

2016-08-27

Jupiter north polar region is coming into view as NASA Juno spacecraft approaches the giant planet. This view of Jupiter was taken on August 27, when Juno was 437,000 miles 703,000 kilometers away. http://photojournal.jpl.nasa.gov/catalog/PIA20895

NASA's Proposed Budget Sees Small Dip, Emphasizes Innovation and Autonomy in Space

NASA Astrophysics Data System (ADS)

Kumar, Mohi

2014-03-01

NASA's proposed federal budget for fiscal year (FY) 2015, released on 4 March, includes new plans to send a probe to Jupiter's icy moon Europa, a ramp up in funding for a mission to redirect an asteroid into near-Earth orbit, funds to extend the life of the International Space Station (ISS) by at least a decade, and plans to return to the United States the capability to launch astronauts into space, among other highlights.

Europa - Full Disk

NASA Image and Video Library

1996-08-09

This picture of Europa, the smallest Galilean satellite, was taken in the afternoon of March 4, 1979, from a distance of about 2 million kilometers 1.2 million miles by NASA Voyager 1. http://photojournal.jpl.nasa.gov/catalog/PIA00016

Jupiter's Moons: Family Portrait

NASA Technical Reports Server (NTRS)

2007-01-01

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

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

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

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

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

Europa Spacecraft Configuration Optimization for the Solar Powered Vehicle

NASA Technical Reports Server (NTRS)

Horner, Matthew D.; Eremenko, Alexander

2016-01-01

A mission to Europa has been on the minds of NASA and JPL for many years. After the Galileo mission to Jupiter in the 1990s there have been various proposals for missions to the Jovian moon. The most recent proposal, previously named the Europa Clipper, has gone through numerous iterations of spacecraft configurations on its road to becoming an official NASA project in June of 2015. Most of these configurations included options for either multi mission radioisotope thermoelectric generators (MMRTGs) or solar power. In 2014, the decision was made to focus on solar arrays as the source for spacecraft power. The decision to move forward with a baseline design that utilized only solar arrays as its power system meant that some configuration choices had to be re- evaluated. Initially, a configuration was adapted to keep as much of the previous spacecraft design the same while replacing MMRTGs with solar panels. This proved to be difficult as the arrays presented a slew of new challenges that the nuclear vehicle was not optimized for. The solar arrays needed to be large due to Jupiter's substantial distance from the Sun. This meant that many of the instrument and radiator FOVs would now be obstructed, or would receive reflected light and heat from the large panel s. Also, the mass of the panels meant that mounting near the bottom of the spacecraft would be sub-optimal as the wings would cause major disturbance to the vehicle as they oscillated in their deployed state. Another major, and possibly the largest, concern was the fact that as the high gain antenna pointed to Earth for communication, the Ice Penetrating Radar (IPR) would cast a large shadow on the cell -side of the array. This resulted in an estimated 10% power loss to the vehicle. On top of all this, NASA announced the selection of the instruments that would fly on the Europa mission and replace the notional instrument suite that had been used to develop and submit the project proposal. The selected

The Jupiter system through the eyes of Voyager 1

USGS Publications Warehouse

Smith, B.A.; Soderblom, L.A.; Johnson, T.V.; Ingersoll, A.P.; Collins, S.A.; Shoemaker, E.M.; Hunt, G.E.; Masursky, H.; Carr, M.H.; Davies, M.E.; Cook, A.F.; Boyce, J.; Danielson, G.E.; Owen, Timothy W.; Sagan, C.; Beebe, R.F.; Veverka, J.; Strom, R.G.; McCauley, J.F.; Morrison, D.; Briggs, G.A.; Suomi, V.E.

1979-01-01

The cameras aboard Voyager I have provided a closeup view of the Jupiter system, revealing heretofore unknown characteristics and phenomena associated with the planet's atmosphere and the surfaces of its five major satellites. On Jupiter itself, atmospheric motions-the interaction of cloud systems-display complex vorticity. On its dark side, lightning and auroras are observed. A ring was discovered surrounding Jupiter. The satellite surfaces display dramatic differences including extensive active volcanismn on Io, complex tectonism on Ganymnede and possibly Europa, and flattened remnants of enormous impact features on Callisto. Copyright ?? 1979 AAAS.

Jovian longitudinal asymmetry in Io-related and Europa-related auroral hot spots

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

Dessler, A.J.; Chamberlain, J.W.

1979-06-15

Jupiter's internal magnetic field is markedly non-dipolar. We propose that Io- or Europa-generated auroral emissions (originating at the foot of either Io's or Europa's magnetic flux tube) are largely restricted to longitudes where Jupiter's ionospheric conductivity is enhanced. Trapped, energetic electrons that drift into Jupiter's atmosphere, in regions where the Jovian magnetic field is anomalously weak, produce the increased conductivity. The longitude range of enchanced auroral hot-spot emissions is thus restricted to an active sector that is determined from dekametric radio emission to lie in the northern hemisphere in the Jovian System III (1965) longitude range of 205/sup 0/ +-more » 30/sup 0/. Relatively weaker auroral hot spots should occur in the southern hemisphere along the mgnetic conjugate trace covering the longitude range of 215/sup 0/ +- 55/sup 0/. At other longitudes, the brightness of the hot spot should decrease by at least one order of magnitude. These results, with respect to both brightness and longitude, are in accord with the observations of Jovian auroral hot spots reported by Atreya et al. We show that the northern hemisphere foot of either Io's or Europa's magnetic flux tube was in the preferred longitude range (the active sector) at the time of each observation.« less

Jupiter's Water Worlds

NASA Technical Reports Server (NTRS)

Pappalardo, R. T.

2004-01-01

When the twin Voyager spacecraft cruised past Jupiter in 1979, they did more than rewrite the textbooks on the giant planet. Their cameras also unveiled the astounding diversity of the four planet-size moons of ice and stone known as the Galilean satellites. The Voyagers revealed the cratered countenance of Callisto, the valleys and ridges of Ganymede, the cracked face of Europa, and the spewing volcanoes of Io. But it would take a spacecraft named for Italian scientist Galileo, who discovered the moons in 1610, to reveal the true complexity of these worlds and to begin to divulge their interior secrets. Incredibly, the Galileo data strongly suggest that Jupiter's three large icy moons (all but rocky Io) hide interior oceans.

Benefits to the Europa Clipper Mission Provided by the Space Launch System

NASA Technical Reports Server (NTRS)

Creech, Stephen D.; Patel, Keyur

2013-01-01

The National Aeronautics and Space Administration's (NASA's) proposed Europa Clipper mission would provide an unprecedented look at the icy Jovian moon, and investigate its environment to determine the possibility that it hosts life. Focused on exploring the water, chemistry, and energy conditions on the moon, the spacecraft would examine Europa's ocean, ice shell, composition and geology by performing 32 low-altitude flybys of Europa from Jupiter orbit over 2.3 years, allowing detailed investigations of globally distributed regions of Europa. In hopes of expediting the scientific program, mission planners at NASA's Jet Propulsion Laboratory are working with the Space Launch System (SLS) program, managed at Marshall Space Flight Center. Designed to be the most powerful launch vehicle ever flown, SLS is making progress toward delivering a new capability for exploration beyond Earth orbit. The SLS rocket will offer an initial low-Earth-orbit lift capability of 70 metric tons (t) beginning with a first launch in 2017 and will then evolve into a 130 t Block 2 version. While the primary focus of the development of the initial version of SLS is on enabling human exploration missions beyond low Earth orbit using the Orion Multi-Purpose Crew Vehicle, the rocket offers unique benefits to robotic planetary exploration missions, thanks to the high characteristic energy it provides. This paper will provide an overview of both the proposed Europa Clipper mission and the Space Launch System vehicle, and explore options provided to the Europa Clipper mission for a launch within a decade by a 70 t version of SLS with a commercially available 5-meter payload fairing, through comparison with a baseline of current Evolved Expendable Launch Vehicle (EELV) capabilities. Compared to that baseline, a mission to the Jovian system could reduce transit times to less than half, or increase mass to more than double, among other benefits. In addition to these primary benefits, the paper will

The San Andreas Fault and a Strike-slip Fault on Europa

NASA Technical Reports Server (NTRS)

1998-01-01

materials, but may be filled in mostly by sedimentary and erosional material deposited from above. Comparisons between faults on Europa and Earth may generate ideas useful in the study of terrestrial faulting.

One theory is that fault motion on Europa is induced by the pull of variable daily tides generated by Jupiter's gravitational tug on Europa. The tidal tension opens the fault; subsequent tidal stress causes it to move lengthwise in one direction. Then the tidal forces close the fault up again. This prevents the area from moving back to its original position. If it moves forward with the next daily tidal cycle, the result is a steady accumulation of these lengthwise offset motions.

Unlike Europa, here on Earth, large strike-slip faults such as the San Andreas are set in motion not by tidal pull, but by plate tectonic forces from the planet's mantle.

North is to the top of the picture. The Earth picture (left) shows a LandSat Thematic Mapper image acquired in the infrared (1.55 to 1.75 micrometers) by LandSat5 on Friday, October 20th 1989 at 10:21 am. The original resolution was 28.5 meters per picture element.

The Europa picture (right)is centered at 66 degrees south latitude and 195 degrees west longitude. The highest resolution frames, obtained at 40 meters per picture element with a spacecraft range of less than 4200 kilometers (2600 miles), are set in the context of lower resolution regional frames obtained at 200 meters per picture element and a range of 22,000 kilometers (13,600 miles). The images were taken on September 26, 1998 by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images

Exploring Europa's Habitability: Science achieved from the Europa Orbiter and Clipper Mission Concepts

NASA Astrophysics Data System (ADS)

Senske, D. A.; Prockter, L. M.; Pappalardo, R. T.; Patterson, G. W.; Vance, S.

2012-12-01

Europa is a prime candidate in the search for present-day habitable environments in our solar system. Europa is unique among the large icy satellites because it probably has a saltwater ocean today beneath an ice shell that is geodynamically active. The combination of irradiation of its surface and tidal heating of its interior could make Europa a rich source of chemical energy for life. Perhaps most importantly, Europa's ocean is believed to be in direct contact with its rocky mantle, where conditions could be similar to those on Earth's biologically rich sea floor. Hydrothermal zones on Earth's seafloor are known to be rich with life, powered by energy and nutrients that result from reactions between the seawater and the warm rocky ocean floor. Life as we know it depends on three principal "ingredients": 1) a sustained liquid water environment; 2) essential chemical elements that are critical for building life; and 3) a source of energy that could be utilized by life. Europa's habitability requires understanding whether it possesses these three ingredients. NASA has enlisted a study team to consider Europa mission options feasible over the next decade, compatible with NASA's projected planetary science budget and addressing Planetary Decadal Survey priorities. Two Europa mission concepts (Orbiter and multiple flyby—call the "Clipper") are undergoing continued study with the goal to "Explore Europa to investigate its habitability." Each mission would address this goal in complementary ways, with high science value of its own. The Orbiter and Clipper architectures lend themselves to specific types of scientific measurements. The Orbiter concept is tailored to the unique geophysical science that requires being in orbit at Europa. This includes confirming the existence of an ocean and characterizing that ocean through geophysical measurements of Europa's gravitational tides and magnetic induction response. It also includes mapping of the global morphology and

Gravity is the Key Experiment to Address the Habitability of the Ocean in Jupiter's Moon Europa

NASA Astrophysics Data System (ADS)

Sessa, A. M.; Dombard, A. J.

2013-12-01

Life requires three constituents: a liquid solvent (i.e., water), a chemical system that can form large molecules to record genetic information (e.g., carbon based) as well as chemical nutrients (e.g., nitrogen, phosphorous), and a chemical disequilibrium system that can provide metabolic energy. While it is believed that there is a saline water layer located between the rock and ice layers in Jupiter's moon Europa, which would satisfy the first requirement, it is unknown if the other conditions are currently met. The likelihood that Europa is a haven for life in our Solar System skyrockets, however, if there is currently active volcanism at the rock-water interface, much the same that volcanic processes enable the chemosynthetic life that forms the basis of deep sea-vent communities at the bottom of Earth's oceans. Exploring the volcanic activity on this interface is challenging, as direct observation via a submersible or high-resolution indirect observations via a dense global seismic network on the surface is at present technically (and fiscally!) untenable. Thus, gravity studies are the best way to explore currently the structure of this all-important interface. Though mostly a silicate body with only a relatively thin (~100 km) layer of water, Europa is different from the terrestrial planets in that this rock-water interface, and not the surface, represents the largest density contrast across the moon's near-surface layers, and thus topography on this interface could conceivably dominate the gravity. Here, we calculate the potential anomalies that arise from topography on the surface, the water-ice interface (at 20 km depth), and the rock-water interface, finding that the latter dominates the free-air gravity at the longest wavelengths (spherical harmonic degrees < 10) and the Bouguer gravity at intermediate wavelengths (degrees ~10-50), and only for the shortest wavelengths (degrees > 50) does the water-ice interface (and presumably mass-density anomalies

Active Cryovolcanism on Europa?

NASA Astrophysics Data System (ADS)

Sparks, W. B.; Schmidt, B. E.; McGrath, M. A.; Hand, K. P.; Spencer, J. R.; Cracraft, M.; E Deustua, S.

2017-04-01

Evidence for plumes of water on Europa has previously been found using the Hubble Space Telescope using two different observing techniques. Roth et al. found line emission from the dissociation products of water. Sparks et al. found evidence for off-limb continuum absorption as Europa transited Jupiter. Here, we present a new transit observation of Europa that shows a second event at the same location as a previous plume candidate from Sparks et al., raising the possibility of a consistently active source of erupting material on Europa. This conclusion is bolstered by comparison with a nighttime thermal image from the Galileo Photopolarimeter-Radiometer that shows a thermal anomaly at the same location, within the uncertainties. The anomaly has the highest observed brightness temperature on the Europa nightside. If heat flow from a subsurface liquid water reservoir causes the thermal anomaly, its depth is ≈1.8-2 km, under simple modeling assumptions, consistent with scenarios in which a liquid water reservoir has formed within a thick ice shell. Models that favor thin regions within the ice shell that connect directly to the ocean, however, cannot be excluded, nor modifications to surface thermal inertia by subsurface activity. Alternatively, vapor deposition surrounding an active vent could increase the thermal inertia of the surface and cause the thermal anomaly. This candidate plume region may offer a promising location for an initial characterization of Europa’s internal water and ice and for seeking evidence of Europa’s habitability.

Jupiter Great Red Spot

NASA Image and Video Library

1997-09-07

This view of Jupiter Great Red Spot is a mosaic of two images taken by NASA Galileo spacecraft. The Great Red Spot is a storm in Jupiter atmosphere and is at least 300 years-old. The image was taken on June 26, 1996. http://photojournal.jpl.nasa.gov/catalog/PIA00296

NASA's Hubble Shows Jupiter's Great Red Spot is Smaller than Ever

NASA Image and Video Library

2014-05-15

In this comparison image the photo at the top was taken by Hubble's Wide Field Planetary Camera 2 in 1995 and shows the spot at a diameter of just under 21 000km; the second down shows a 2009 WFC3 photo of the spot at a diameter of just under 18 000km; and the lowest shows the newest image from WFC3 taken in 2014 with the spot at its smallest yet, with diameter of just 16 000km. -- Jupiter's trademark Great Red Spot -- a swirling anti-cyclonic storm larger than Earth -- has shrunk to its smallest size ever measured. According to Amy Simon of NASA's Goddard Space Flight Center in Greenbelt, Maryland, recent NASA Hubble Space Telescope observations confirm the Great Red Spot now is approximately 10,250 miles across. Astronomers have followed this downsizing since the 1930s. Historic observations as far back as the late 1800s gauged the storm to be as large as 25,500 miles on its long axis. NASA Voyager 1 and Voyager 2 flybys of Jupiter in 1979 measured it to be 14,500 miles across. In 1995, a Hubble photo showed the long axis of the spot at an estimated 13,020 miles across. And in a 2009 photo, it was measured at 11,130 miles across. Beginning in 2012, amateur observations revealed a noticeable increase in the rate at which the spot is shrinking -- by 580 miles per year -- changing its shape from an oval to a circle. Read more: 1.usa.gov/1mvuo0R Credit: NASA/ESA 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

Tides and the Biosphere of Europa

NASA Astrophysics Data System (ADS)

Greenberg, Richard

2002-01-01

It's been suspected for at least a decade now that Jupiter's icy moon Europa harbors a global ocean of liquid water beneath its crust. To many scientists the presence of another ocean in our solar system immediately conjured up images of extraterrestrial lifeforms swimming in an alien sea. But what sorts of life could evolve in the dark waters of a subsurface ocean, and how would it derive the energy it needs to survive? Planetary scientist, Richard Greenberg has been studying the surface features of Europa, and he finds that the icy crust that covers the ocean may not be as thick as scientists had at first supposed. Cracks in Europa's surface suggest that the ocean waters may come very close to the surface. If so, the cracks themselves may provide a niche for life, and the light near the surface of the moon could provide energy for photosynthetic organisms.

Tidal reorientation and the fracturing of Jupiter's moon Europa

NASA Technical Reports Server (NTRS)

Mcewen, A. S.

1986-01-01

The lineaments on Europa are discussed in terms of the orientation of the lineaments relative to the tensile stress trajectories due to tidal distortions and to nonsynchronous rotation. The cracks are noticeable by their darker albedo compared to the presumed water ice surrounding them. The stress trajectories for tidal distortion of a thin elastic shell are superimposed on Mercator projection maps of the lineaments. It is shown that the lineaments are mainly oriented at high angles to the tensile stress trajectories that would be expected for regularly occurring nonsynchronous rotation, i.e., extensional fractures would appear. The reorientation motions which would cause the fractures are estimated. It is suggested that the fractures occur episodically to release stresses built up on the tensile surface of the crust during the continuous nonsynchronous rotation of Europa.

Europa Ice Cliffs-High Resolution

NASA Technical Reports Server (NTRS)

1998-01-01

This view of the Conamara Chaos region on Jupiter's moon Europa shows cliffs along the edges of high-standing ice plates. The washboard texture of the older terrain has been broken into plates which are separated by material with a jumbled texture. The cliffs themselves are rough and broadly scalloped, and smooth debris shed from the cliff faces is piled along the base. For scale, the height of the cliffs and size of the scalloped indentations are comparable to the famous cliff face of Mount Rushmore in South Dakota.

This image was taken on December 16, 1997 at a range of 900 kilometers (540 miles) by the solid state imaging system (camera) on NASA's Galileo spacecraft. North is to the top right of the picture, and the sun illuminates the surface from the east. This image, centered at approximately 8 degrees north latitude and 273 degrees west longitude, covers an area approximately 1.5 kilometers by 4 kilometers (0.9 miles by 2.4 miles). The resolution is 9 meters (30 feet) per picture element.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

Artist's Concept of Jupiter Lightning

NASA Image and Video Library

2018-06-06

This artist's concept of lightning distribution in Jupiter's northern hemisphere incorporates a JunoCam image with artistic embellishments. Data from NASA's Juno mission indicates that most of the lightning activity on Jupiter is near its poles. https://photojournal.jpl.nasa.gov/catalog/PIA22474

Active Cryovolcanism on Europa?

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

Sparks, W. B.; Cracraft, M.; Deustua, S. E

Evidence for plumes of water on Europa has previously been found using the Hubble Space Telescope using two different observing techniques. Roth et al. found line emission from the dissociation products of water. Sparks et al. found evidence for off-limb continuum absorption as Europa transited Jupiter. Here, we present a new transit observation of Europa that shows a second event at the same location as a previous plume candidate from Sparks et al., raising the possibility of a consistently active source of erupting material on Europa. This conclusion is bolstered by comparison with a nighttime thermal image from the Galileomore » Photopolarimeter-Radiometer that shows a thermal anomaly at the same location, within the uncertainties. The anomaly has the highest observed brightness temperature on the Europa nightside. If heat flow from a subsurface liquid water reservoir causes the thermal anomaly, its depth is ≈1.8–2 km, under simple modeling assumptions, consistent with scenarios in which a liquid water reservoir has formed within a thick ice shell. Models that favor thin regions within the ice shell that connect directly to the ocean, however, cannot be excluded, nor modifications to surface thermal inertia by subsurface activity. Alternatively, vapor deposition surrounding an active vent could increase the thermal inertia of the surface and cause the thermal anomaly. This candidate plume region may offer a promising location for an initial characterization of Europa’s internal water and ice and for seeking evidence of Europa’s habitability.« less

Juno Closes in on Jupiter

NASA Image and Video Library

2016-07-04

This is the final view taken by the JunoCam instrument on NASA's Juno spacecraft before Juno's instruments were powered down in preparation for orbit insertion. Juno obtained this color view on June 29, 2016, at a distance of 3.3 million miles (5.3 million kilometers) from Jupiter. The spacecraft is approaching over Jupiter's north pole, providing an unprecedented perspective on the Jupiter system, including its four large moons. http://photojournal.jpl.nasa.gov/catalog/PIA20706

HUBBLE SPACE TELESCOPE/ADVANCED CAMERA FOR SURVEYS OBSERVATIONS OF EUROPA'S ATMOSPHERIC ULTRAVIOLET EMISSION AT EASTERN ELONGATION

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

Saur, Joachim; Roth, Lorenz; Schilling, Nico

2011-09-10

We report results of a Hubble Space Telescope (HST) campaign with the Advanced Camera for Surveys to observe Europa at eastern elongation, i.e., Europa's leading side, on 2008 June 29. With five consecutive HST orbits, we constrain Europa's atmospheric O I 1304 A and O I 1356 A emissions using the prism PR130L. The total emissions of both oxygen multiplets range between 132 {+-} 14 and 226 {+-} 14 Rayleigh. An additional systematic error with values on the same order as the statistical errors may be due to uncertainties in modeling the reflected light from Europa's surface. The total emissionmore » also shows a clear dependence of Europa's position with respect to Jupiter's magnetospheric plasma sheet. We derive a lower limit for the O{sub 2} column density of 6 x 10{sup 18} m{sup -2}. Previous observations of Europa's atmosphere with the Space Telescope Imaging Spectrograph in 1999 of Europa's trailing side show an enigmatic surplus of radiation on the anti-Jovian side within the disk of Europa. With emission from a radially symmetric atmosphere as a reference, we searched for an anti-Jovian versus sub-Jovian asymmetry with respect to the central meridian on the leading side and found none. Likewise, we searched for departures from a radially symmetric atmospheric emission and found an emission surplus centered around 90 deg. west longitude, for which plausible mechanisms exist. Previous work about the possibility of plumes on Europa due to tidally driven shear heating found longitudes with strongest local strain rates which might be consistent with the longitudes of maximum UV emissions. Alternatively, asymmetries in Europa's UV emission can also be caused by inhomogeneous surface properties, an optically thick atmospheric contribution of atomic oxygen, and/or by Europa's complex plasma interaction with Jupiter's magnetosphere.« less

Comparison of high-energy trapped particle environments at the Earth and Jupiter.

PubMed

Jun, Insoo; Garrett, Henry B

2005-01-01

The 'Van Allen belts' of the trapped energetic particles in the Earth's magnetosphere were discovered by the Explorer I satellite in 1958. In addition, in 1959, it was observed that UHF radio emissions from Jupiter probably had a similar source--the Jovian radiation belts. In this paper, the global characteristics of these two planets' trapped radiation environments and respective magnetospheres are compared and state-of-the-art models used to generate estimates of the high-energy electron (> or = 100 keV) and proton (> or = 1 MeV) populations--the dominant radiation particles in these environments. The models used are the AP8/AE8 series for the Earth and the Divine-Garrett/GIRE model for Jupiter. To illustrate the relative magnitude of radiation effects at each planet, radiation transport calculations were performed to compute the total ionising dose levels at the geosynchronous orbit for the Earth and at Europa (Jupiter's 4th largest moon) for Jupiter. The results show that the dose rates are -0.1 krad(Si) d(-1) at the geosynchronous orbit and -30 krad(Si) d((-1) at Europa for a 2.5 mm spherical shell aluminium shield--a factor of -300 between the two planets.

Studies for the Europagenic Plasma Source in Jupiter's Inner Magnetosphere during the Galileo Europa Mission

NASA Technical Reports Server (NTRS)

Smyth, William H.

2004-01-01

Progress in research to understand the three-dimensional nature of the Europagenic plasma torus is summarized. Efforts to improve the plasma torus description near Europa's orbit have included a better understanding of Europa's orbit and an improved description of the planetary magnetic field. New plasma torus chemistry for molecular and atomic species has been introduced and implemented in Europa neutral cloud models. Preliminary three-dimensional model calculations for Europa's neutral clouds and their plasma sources are presented.

Europa During Voyager 2 Closest Approach

NASA Image and Video Library

1996-09-26

This color image of the Jovian moon Europa was acquired by NASA Voyager 2 during its close encounter on Jul. 9, 1979. Europa, the size of our moon, is thought to have a crust of ice perhaps 100 kilometers thick which overlies the silicate crust. The complex array of streaks indicate that the crust has been fractured and filled by materials from the interior. The lack of relief, any visible mountains or craters, on its bright limb is consistent with a thick ice crust. In contrast to its icy neighbors, Ganymede and Callisto, Europa has very few impact craters. One possible candidate is the small feature near the center of this image with radiating rays and a bright circular interior. The relative absence of features and low topography suggests the crust is young and warm a few kilometers below the surface. The tidal heating process suggested for Io also may be heating Europa's interior at a lower rate. http://photojournal.jpl.nasa.gov/catalog/PIA00459

Europa's Pwyll Crater

NASA Technical Reports Server (NTRS)

1998-01-01

This view of the Pwyll impact crater on Jupiter's moon Europa taken by NASA's Galileo spacecraft shows the interior structure and surrounding ejecta deposits. Pwyll's location is shown in the background global view taken by Galileo's camera on December 16, 1997. Bright rays seen radiating from Pwyll in the global image indicate that this crater is geologically young. The rim of Pwyll is about 26 kilometers (16 miles) in diameter, and a halo of dark material excavated from below the surface extends a few kilometers beyond the rim. Beyond this dark halo, the surface is bright and numerous secondary craters can be seen. The closeup view of Pwyll, which combines imaging data gathered during the December flyby and the flyby of February 20, 1997, indicates that unlike most fresh impact craters, which have much deeper floors, Pwyll's crater floor is at approximately the same level as the surrounding background terrain.

North is to the top of the picture and the sun illuminates the surface from the northeast. This closeup image, centered at approximately 26 degrees south latitude and 271 degrees west longitude, covers an area approximately 125 by 75 kilometers (75 by 45 miles). The finest details that can be discerned in this picture are about 250 meters (800 feet) across. This image was taken on at a range of 12,400 kilometers (7,400 miles), with the green filter of Galileo's solid state imaging system.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

Europa Wedge Region

NASA Technical Reports Server (NTRS)

1998-01-01

This image shows an area of crustal separation on Jupiter's moon, Europa. Lower resolution pictures taken earlier in the tour of NASA's Galileo spacecraft revealed that dark wedge-shaped bands in this region are areas where the icy crust has completely pulled apart. Dark material has filled up from below and filled the void created by this separation.

In the lower left corner of this image, taken by Galileo's onboard camera on December 16, 1997, a portion of one dark wedge area is visible, revealing a linear texture along the trend of the wedge. The lines of the texture change orientation slightly and reflect the fact that we are looking at a bend in the wedge. The older, bright background, visible on the right half of the image, is criss-crossed with ridges. A large, bright ridge runs east-west through the upper part of the image, cutting across both the older background plains and the wedge. This ridge is rough in texture, with numerous small terraces and troughs containing dark material.

North is to the top of the picture and the sun illuminates the surface from the northwest. This image, centered at approximately 16.5 degrees south latitude and 196.5 degrees west longitude, covers an area approximately 10 kilometers square (about 6.5 miles square). The resolution of this image is about 26 meters per picture element. This image was taken by the solid state imaging system from a distance of 1250 kilometers (750 miles).

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

Approaching Jupiter

NASA Image and Video Library

2017-05-05

This enhanced color view of Jupiter's south pole was created by citizen scientist Gabriel Fiset using data from the JunoCam instrument on NASA's Juno spacecraft. Oval storms dot the cloudscape. Approaching the pole, the organized turbulence of Jupiter's belts and zones transitions into clusters of unorganized filamentary structures, streams of air that resemble giant tangled strings. The image was taken on Dec. 11, 2016 at 9:44 a.m. PST (12:44 p.m. EST), from an altitude of about 32,400 miles (52,200 kilometers) above the planet's beautiful cloud tops. https://photojournal.jpl.nasa.gov/catalog/PIA21390

Asymmetry of reflective properties of the hemispheres of Jupiter satellite Europa

NASA Astrophysics Data System (ADS)

Vidmachenko, Anatoliy; Morozhenko, A.; Klyanchin, A.; Shavlovskiy, V.; Ivanov, Yu.; Kostogryz, N.

2011-12-01

Rotation around the central planet of Europa is synchronous. Leading hemisphere - is much brighter and less polluted by "no ice" material than the trailing one. The high albedo of the satellite may indicates that the ice on the surface is clean enough and is formed recently: 1,5-30 million years ago. Comparison of surface images of spacecrafts "Voyager" and "Galileo" with a low spatial resolution did not detect any significant changes during 20 years. But a detailed analysis of observational data with high resolution points to a number of features on the surface, which may indicate a change in the geological structures during this time. Spectral geometric albedo in the wavelength range 346-750 nm of leading and trailing hemispheres of Galilean satellites were defined using of our spectral observations in 2009 and 2010 and the observations of the other authors at different values of orbital and solar phase angles. The high geometric albedo in the red region of Io and Europa spectrum are confirmed; albedo of Io decreases sharply with decreasing of wavelength for ? < 500 nm; albedo of Ganymede and Callisto - reduced smoothly; albedo of Europa - have an intermediate gradient of reduction. Such behavior of the spectral variation of Europa surface albedo can be explained by deposition of sulfur from Io. Moreover, the sulfur absorption is more strongly on the trailing hemisphere. This indicates that the sulfur on the leading hemisphere is "processed" by meteoritic bombardment much faster and is gone to the the sub-surface regolith layer.

Jupiter Eye to Io

NASA Image and Video Library

2000-12-12

This image taken by NASA Cassini spacecraft on Dec. 1, 2000, shows details of Jupiter Great Red Spot and other features that were not visible in images taken earlier, when Cassini was farther from Jupiter.

Jupiter's Dynamic Atmosphere

NASA Image and Video Library

2018-05-09

This image captures the dynamic nature of Jupiter's northern temperate belt. The view reveals a white, oval-shaped anticyclonic storm called WS-4. NASA's Juno spacecraft took this color-enhanced image on April 1 at 2:38 a.m. PST (5:38 a.m. EST) during its 12th close flyby of the gas giant planet. At the time, the spacecraft was 4,087 miles (6,577 kilometers) from the tops of Jupiter's clouds at 35.6 degrees north latitude. This image was created by citizen scientist Emma Walimaki using data from the JunoCam imager on NASA's Juno spacecraft. https://photojournal.jpl.nasa.gov/catalog/PIA22420

Dark Matter Hairs Around Jupiter

NASA Image and Video Library

2015-11-23

This illustration shows Jupiter surrounded by filaments of dark matter called "hairs," which are proposed in a study in the Astrophysical Journal by Gary Prézeau of NASA's Jet Propulsion Laboratory, Pasadena, California. A hair is created when a stream of dark matter particles goes through the planet. According to simulations, the hair is densest at a point called the "root." When particles of a dark matter stream pass through the core of Jupiter, they form a hair whose root has a particle density about a trillion times greater than average. The size of Jupiter relative to the distance between Jupiter and the hair roots is to scale. http://photojournal.jpl.nasa.gov/catalog/PIA20178

Voyager 2 Jupiter encounter

NASA Technical Reports Server (NTRS)

1979-01-01

A NASA News Release is presented which contains the following: (1) general release; (2) two views of Voyager 2 flight past Jupiter; (3) Voyager mission summary; (4) Voyager 1 science results; (5) Jupiter science objectives; (6) Jupiter the planet and its satellites; (7) Voyager experiments; (8) planet comparison; (9) a list of Voyager science investigators and (10) the Voyager team.

Jupiter Temperatures--Broad Latitude

NASA Image and Video Library

1997-09-23

This is one of the highest resolution images ever recorded of Jupiter temperature field. It was obtained by NASA Galileo mission, with its Photopolarimeter-Radiometer PPR experiment, during the seventh of its 10 orbits around Jupiter to date.

The Edge of Jupiter

NASA Image and Video Library

2017-04-19

This enhanced color Jupiter image, taken by the JunoCam imager on NASA's Juno spacecraft, showcases several interesting features on the apparent edge (limb) of the planet. Prior to Juno's fifth flyby over Jupiter's mysterious cloud tops, members of the public voted on which targets JunoCam should image. This picture captures not only a fascinating variety of textures in Jupiter's atmosphere, it also features three specific points of interest: "String of Pearls," "Between the Pearls," and "An Interesting Band Point." Also visible is what's known as the STB Spectre, a feature in Jupiter's South Temperate Belt where multiple atmospheric conditions appear to collide. JunoCam images of Jupiter sometimes appear to have an odd shape. This is because the Juno spacecraft is so close to Jupiter that it cannot capture the entire illuminated area in one image -- the sides get cut off. Juno acquired this image on March 27, 2017, at 2:12 a.m. PDT (5:12 a.m. EDT), as the spacecraft performed a close flyby of Jupiter. When the image was taken, the spacecraft was about 12,400 miles (20,000 kilometers) from the planet. This enhanced color image was created by citizen scientist Bjorn Jonsson. https://photojournal.jpl.nasa.gov/catalog/PIA21389

Study of the Jupiter X-ray imaging spectrometer on JMO

NASA Astrophysics Data System (ADS)

Kimura, T.; Ezoe, Y.; Kasahara, S.; Miyoshi, Y.; Yamazaki, A.; Fujimoto, M.; JMO X-ray Experiment Team

2011-12-01

In 2000's, the new generation X-ray observatories (Chandra, XMM-Newton and Suzaku) have revealed various new X-ray phenomena in the Jupiter system. The detected objects include Jupiter's aurorae, disk (middle and low-latitude emission), Io, Europa, the Io Plasma Torus, and radiation belts. For example, Jupiter's aurorae emit time variable X-rays via bremsstrahlung by keV electrons and charge exchange by MeV ions (Gladstone et al. 2002 Nature). A diffuse X-ray emission associated with the Jupiter's radiation belts suggests an inverse Compton scattering of tens MeV electrons (Ezoe et al. 2010 ApJ). Hence, the X-ray emission can be a unique diagnostic tool to investigate key fundamental problems on the Jupiter system such as the relativistic particle acceleration and the Jupiter-satellite reaction. However, since these observations have been done with the X-ray astronomy satellites orbiting the Earth, the photon statistics of X-ray spectra and light curves, and the angular resolution of X-ray images were severely limited. In this context, we have started to study design of an X-ray imaging spectrometer for JMO (Jupiter Magnetospheric Orbiter) which is expected to collaborate with international Jupiter exploration mission JUICE (JUpiter ICy moon Explorer). JUICE is originally EJSM (Europa Jupiter System Mission) but recently renamed JUICE as ESA-lead mission, which is proposed to be launched in 2020's. It consists of one main flight element developed by ESA to explore icy moons of Jupiter, and JMO by JAXA is expected to perform high-latitude (10-30 deg inclination) measurements of the Jupiter system and overview the magnetospheric activities. The in-situ measurements by EJSM JMO provide us with an unprecedented opportunity to observe Jupiter with extremely high photon statistics, high time and angular resolution. To realize the in-situ X-ray instrument for EJSM JMO, stringent mass and power limitations must be fulfilled. Furthermore, the radiation and the contamination

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.

High Resolution Integral Field Spectroscopy of Europa's Sodium Clouds: Evidence for a Component with Origins in Iogenic Plasma.

NASA Astrophysics Data System (ADS)

Schmidt, C.; Johnson, R. E.; Mendillo, M.; Baumgardner, J. L.; Moore, L.; O'Donoghue, J.; Leblanc, F.

2015-12-01

With the object of constraining Iogenic contributions and identifying drivers for variability, we report new observations of neutral sodium in Europa's exosphere. An R~20000 integral field spectrograph at McDonald Observatory is used to generate Doppler maps of sodium cloud structures with a resolution of 2.8 km/s/pixel. In the five nights of observations since 2011, measurements on UT 6.15-6.31 May 2015 uniquely feature fast (10s of km/s) neutral sodium clouds extending nearly 100 Europa radii, more distant than in any previous findings. During these measurements, the satellite geometry was favorable for the transfer of Na from Io to Europa, located at 1:55 to 4:00 and 3:38 to 4:39 Jovian local time, respectively. Eastward emission (away from Jupiter) extends 10-20 Europa radii retaining the moon's rest velocity, while westward emission blue-shifts with distance, and a broad range of velocities are measured, reaching at least 70 km/s at 80 Europa radii. These cloud features are distinct from Io's "banana" and "stream" features, the distant Jupiter-orbiting nebula, and from terrestrial OH and Na contaminant emissions. Io's production was quiescent during this observation, following an extremely active phase in February 2015. These results are consistent with previous findings that Europa's Na exosphere has peak emission between midnight and dawn Jovian local time and support the idea that sodium escape from Io can significantly enhance the emission intensity measured at Europa.

High Above Jupiter's Clouds

NASA Image and Video Library

2018-01-04

NASA's Juno spacecraft was a little more than one Earth diameter from Jupiter when it captured this mind-bending, color-enhanced view of the planet's tumultuous atmosphere. Jupiter completely fills the image, with only a hint of the terminator (where daylight fades to night) in the upper right corner, and no visible limb (the curved edge of the planet). Juno took this image of colorful, turbulent clouds in Jupiter's northern hemisphere on Dec. 16, 2017 at 9:43 a.m. PST (12:43 p.m. EST) from 8,292 miles (13,345 kilometers) above the tops of Jupiter's clouds, at a latitude of 48.9 degrees. The spatial scale in this image is 5.8 miles/pixel (9.3 kilometers/pixel).. Citizen scientists Gerald Eichstädt and Seán Doran processed this image using data from the JunoCam imager. https://photojournal.jpl.nasa.gov/catalog/PIA21973

Evidence of Plume on Europa from Galileo Magnetic and Plasma Density Signatures

NASA Astrophysics Data System (ADS)

Jia, X.; Kivelson, M.; Khurana, K. K.; Kurth, W. S.

2017-12-01

The icy surface of Jupiter's moon, Europa, is thought to lie on top of a global ocean [Khurana et al., 1998; Kivelson et al., 2000]. Water plumes rising 200 kilometers above the disk of the solid body in some Hubble Space Telescope images have been identified through emission spectra of hydrogen and oxygen [Roth et al., 2016] and through absorption in the far ultraviolet of sunlight reflected off of Jupiter [Sparks et al., 2016, 2017]. Plume activity appears to be intermittent, although Sparks et al. [2017] identified a plume at a location where one had been detected in an earlier study. While the detections appear to be valid within statistical uncertainty, they are all close to the limit of detection, making it desirable to find other evidence of the presence of localized vapor above Europa's surface. In this presentation, we examine magnetometer and electromagnetic wave data acquired by the Galileo spacecraft on a close encounter with Europa on December 16, 1997. We identify distinct features in the data that have the characteristics expected if the spacecraft went through magnetic flux tubes that pass around a plume, close to the location proposed for one of the plumes observed by Sparks et al. [2016]. 3D magnetohydrodynamic simulations have been conducted to model the interaction of plume with Europa's plasma and magnetic environment. Our simulations confirm that the magnetic and plasma signatures identified in the Galileo data are consistent with perturbations associated with a localized plume source.

Jupiter's Northern Lights

NASA Image and Video Library

2017-09-06

This is a reconstructed view of Jupiter's northern lights through the filters of Juno's Ultraviolet Imaging Spectrometer (UVS) instrument on Dec. 11, 2016, as the Juno spacecraft approached Jupiter, passed over its poles, and plunged towards the equator. Such measurements present a real challenge for the spacecraft's science instruments: Juno flies over Jupiter's poles at 30 miles (50 kilometers) per second -- more than 100,000 miles per hour -- speeding past auroral forms in a matter of seconds. https://photojournal.jpl.nasa.gov/catalog/PIA21938

Abstract Jupiter Atmosphere (Artist Concept)

NASA Image and Video Library

2018-03-28

Citizen scientist Rick Lundh created this abstract Jovian artwork using data from the JunoCam imager onboard NASA's Juno spacecraft. The original image captures a close-up view of numerous storms in the northern hemisphere of Jupiter. To produce this artwork, Lundh selected a more contrasting part of one of Jupiter's storms, then cropped the image and applied an oil-painting filter. https://photojournal.jpl.nasa.gov/catalog/PIA21983

NASA's Planetary Science Missions and Participations

NASA Astrophysics Data System (ADS)

Daou, Doris; Green, James L.

2017-04-01

NASA's Planetary Science Division (PSD) and space agencies around the world are collaborating on an extensive array of missions exploring our solar system. Planetary science missions are conducted by some of the most sophisticated robots ever built. International collaboration is an essential part of what we do. NASA has always encouraged international participation on our missions both strategic (ie: Mars 2020) and competitive (ie: Discovery and New Frontiers) and other Space Agencies have reciprocated and invited NASA investigators to participate in their missions. NASA PSD has partnerships with virtually every major space agency. For example, NASA has had a long and very fruitful collaboration with ESA. ESA has been involved in the Cassini mission and, currently, NASA funded scientists are involved in the Rosetta mission (3 full instruments, part of another), BepiColombo mission (1 instrument in the Italian Space Agency's instrument suite), and the Jupiter Icy Moon Explorer mission (1 instrument and parts of two others). In concert with ESA's Mars missions NASA has an instrument on the Mars Express mission, the orbit-ground communications package on the Trace Gas Orbiter (launched in March 2016) and part of the DLR/Mars Organic Molecule Analyzer instruments going onboard the ExoMars Rover (to be launched in 2018). NASA's Planetary Science Division has continuously provided its U.S. planetary science community with opportunities to include international participation on NASA missions too. For example, NASA's Discovery and New Frontiers Programs provide U.S. scientists the opportunity to assemble international teams and design exciting, focused planetary science investigations that would deepen the knowledge of our Solar System. The PSD put out an international call for instruments on the Mars 2020 mission. This procurement led to the selection of Spain and Norway scientist leading two instruments and French scientists providing a significant portion of another

Jupiter Swirling Pearl Storm

NASA Image and Video Library

2017-03-30

This image, taken by the JunoCam imager on NASA's Juno spacecraft, highlights a swirling storm just south of one of the white oval storms on Jupiter. The image was taken on March 27, 2017, at 2:12 a.m. PDT (5:12 a.m. EDT), as the Juno spacecraft performed a close flyby of Jupiter. At the time the image was taken, the spacecraft was about 12,400 miles (20,000 kilometers) from the planet. Citizen scientist Jason Major enhanced the color and contrast in this image, turning the picture into a Jovian work of art. He then cropped it to focus our attention on this beautiful example of Jupiter's spinning storms. https://photojournal.jpl.nasa.gov/catalog/PIA21387

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

Evidence for non-synchronous rotation of Europa. Galileo Imaging Team.

PubMed

Geissler, P E; Greenberg, R; Hoppa, G; Helfenstein, P; McEwen, A; Pappalardo, R; Tufts, R; Ockert-Bell, M; Sullivan, R; Greeley, R; Belton, M J; Denk, T; Clark, B; Burns, J; Veverka, J

1998-01-22

Non-synchronous rotation of Europa was predicted on theoretical grounds, by considering the orbitally averaged torque exerted by Jupiter on the satellite's tidal bulges. If Europa's orbit were circular, or the satellite were comprised of a frictionless fluid without tidal dissipation, this torque would average to zero. However, Europa has a small forced eccentricity e approximately 0.01 , generated by its dynamical interaction with Io and Ganymede, which should cause the equilibrium spin rate of the satellite to be slightly faster than synchronous. Recent gravity data suggest that there may be a permanent asymmetry in Europa's interior mass distribution which is large enough to offset the tidal torque; hence, if non-synchronous rotation is observed, the surface is probably decoupled from the interior by a subsurface layer of liquid or ductile ice. Non-synchronous rotation was invoked to explain Europa's global system of lineaments and an equatorial region of rifting seen in Voyager images. Here we report an analysis of the orientation and distribution of these surface features, based on initial observations made by the Galileo spacecraft. We find evidence that Europa spins faster than the synchronous rate (or did so in the past), consistent with the possibility of a global subsurface ocean.

Jupiter Hot Spot Makes Trouble For Theory

NASA Astrophysics Data System (ADS)

2002-02-01

A pulsating hot spot of X-rays has been discovered in the polar regions of Jupiter's upper atmosphere by NASA's Chandra X-ray Observatory. Previous theories cannot explain either the pulsations or the location of the hot spot, prompting scientists to search for a new process to produce Jupiter's X-rays. "The location of the X-ray hot spot effectively retires the existing explanation for Jupiter's X-ray emission, leaving us very unsure of its origin," said Randy Gladstone, of the Southwest Research Institute in San Antonio and lead author of a paper on the results in the Feb.28, 2002 issue of the journal Nature. "The source of ions that produce the X-rays must be a lot farther away from Jupiter than previously believed." Chandra observed Jupiter for 10 hours on Dec. 18, 2000, when NASA's Cassini spacecraft was flying by Jupiter on its way to Saturn. The X-ray observations revealed that most of the auroral X-rays come from a pulsating hot spot that appears at a fixed location near the north magnetic pole of Jupiter. Bright infrared and ultraviolet emissions have also been detected from this region in the past. The X-rays were observed to pulsate with a period of 45 minutes, similar to the period of high-latitude radio pulsations detected by NASA's Galileo and Cassini spacecraft. Jupiter X-ray/UV/Optical Composite Credit: X-ray: NASA/SWRI/R.Gladstone et al. UV: NASA/HST/J.Clarke et al. Optical: NASA/HST/R.Beebe et al. An aurora of X-ray light near Jupiter's polar regions had been detected by previous satellites. However, scientists were unable to determine the exact location of the X-rays. The accepted theory held that the X-rays were produced by energetic oxygen and sulfur ions that became excited as they ran into hydrogen and helium in Jupiter's atmosphere. Oxygen and sulfur ions (originally from Jupiter's moon Io) are energized while circulating around Jupiter's enormous magnetosphere. And, some - the purported X-ray producers - get dumped into Jupiter's atmosphere

Hubble Captures Rare Triple-Moon Conjunction

NASA Image and Video Library

2015-02-06

Three moons and their shadows parade across Jupiter near the end of the event at 07:10 UT on January 24, 2015. Europa has entered the frame at lower left. Slower-moving Callisto is above and to the right of Europa. Fastest-moving Io is approaching the eastern limb of the planet. Europa's shadow is toward the left side of the image and Callisto's shadow to the right. (The moons' orbital velocities are proportionally slower with increasing distance from the planet.) Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA) More info: Firing off a string of snapshots like a sports photographer at a NASCAR race, NASA's Hubble Space Telescope captured a rare look at three of Jupiter's largest moons zipping across the banded face of the gas-giant planet: Europa, Callisto, and Io. Jupiter's four largest moons can commonly be seen transiting the face of the giant planet and casting shadows onto its cloud tops. However, seeing three moons transiting the face of Jupiter at the same time is rare, occurring only once or twice a decade. Missing from the sequence, taken on January 24, 2015, is the moon Ganymede that was too far from Jupiter in angular separation to be part of the conjunction. 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

Evidence for a subsurface ocean on Europa.

PubMed

Carr, M H; Belton, M J; Chapman, C R; Davies, M E; Geissler, P; Greenberg, R; McEwen, A S; Tufts, B R; Greeley, R; Sullivan, R; Head, J W; Pappalardo, R T; Klaasen, K P; Johnson, T V; Kaufman, J; Senske, D; Moore, J; Neukum, G; Schubert, G; Burns, J A; Thomas, P; Veverka, J

1998-01-22

Ground-based spectroscopy of Jupiter's moon Europa, combined with gravity data, suggests that the satellite has an icy crust roughly 150 km thick and a rocky interior. In addition, images obtained by the Voyager spacecraft revealed that Europa's surface is crossed by numerous intersecting ridges and dark bands (called lineae) and is sparsely cratered, indicating that the terrain is probably significantly younger than that of Ganymede and Callisto. It has been suggested that Europa's thin outer ice shell might be separated from the moon's silicate interior by a liquid water layer, delayed or prevented from freezing by tidal heating; in this model, the lineae could be explained by repetitive tidal deformation of the outer ice shell. However, observational confirmation of a subsurface ocean was largely frustrated by the low resolution (>2 km per pixel) of the Voyager images. Here we present high-resolution (54 m per pixel) Galileo spacecraft images of Europa, in which we find evidence for mobile 'icebergs'. The detailed morphology of the terrain strongly supports the presence of liquid water at shallow depths below the surface, either today or at some time in the past. Moreover, lower-resolution observations of much larger regions suggest that the phenomena reported here are widespread.

Evidence for a subsurface ocean on Europa

USGS Publications Warehouse

Carr, M.H.; Belton, M.J.S.; Chapman, C.R.; Davies, M.E.; Geissler, P.; Greenberg, R.; McEwen, A.S.; Tufts, B.R.; Greeley, R.; Sullivan, R.; Head, J.W.; Pappalardo, R.T.; Klaasen, K.P.; Johnson, T.V.; Kaufman, J.; Senske, D.; Moore, J.; Neukum, G.; Schubert, G.; Burns, J.A.; Thomas, P.; Veverka, J.

1998-01-01

Ground-based spectroscopy of Jupiter's moon Europa, combined with gravity data, suggests that the satellite has an icy crust roughly 150 km thick and a rocky interior. In addition, images obtained by the Voyager spacecraft revealed that Europa's surface is crossed by numerous intersecting ridges and dark bands (called lineae) and is sparsely cratered, indicating that the terrain is probably significantly younger than that of Ganymede and Callisto. It has been suggested that Europa's thin outer ice shell might be separated from the moon's silicate interior by a liquid water layer, delayed or prevented from freezing by tidal heating; in this model, the lineae could be explained by repetitive tidal deformation of the outer ice shell. However, observational confirmation of a subsurface ocean was largely frustrated by the low resolution (>2 km per pixel) of the Voyager images. Here we present high-resolution (54 m per pixel) Galileo spacecraft images of Europa, in which we find evidence for mobile 'icebergs'. The detailed morphology of the terrain strongly supports the presence of liquid water at shallow depths below the surface, either today or at some time in the past. Moreover, lower- resolution observations of much larger regions suggest that the phenomena reported here are widespread.

Jupiter System Data Analysis Program: Mechanisms, Manifestation, and Implications of Cryomagmatism on Europa

NASA Technical Reports Server (NTRS)

Fagents, Sarah A.

2003-01-01

The objectives of the work completed under NASA Grant NAG5-8898 were (i) to document and characterize the low-albedo diffuse surfaces associated with triple bands and lenticulae, (ii) to determine their mechanisms of formation, and (iii) to assess the implications of these features for the resurfacing (in space and time) of the Europa and the nature of the Europan interior. The approach involved a combination of processing and analysis of Solid State Imaging data returned by the Galileo spacecraft during the primary and extended mission phases, together with numerical modeling of the physical processes interpreted to the observed features. We have modeled the formation of Europan triple explosive venting of cryoclastic material from bands and lenticulae halos by two processes: (i) a liquid layer in the Europan interior, and (ii) lag deposit formation by the thermal influence of subsurface cryomagmatic intrusions. We favor the latter hypothesis for explaining these features, and further suggest that a liquid water or brine intrusion is required to provide sufficient lateral heating of surface ice to explain the 25 km size of the largest features. (Solid ice diapirs, even under the most favorable conditions, become thermally exhausted before they heat significant lateral distances). We argue that water circulating in open fractures, or repeated cryomagmatic 'diking' events would provide sufficient thermal input to produce the observed features. Thus our work argues for the existence of a liquid beneath Europa's surface. Our results might most easily be explained by the presence of a continuous liquid layer (the putative Europan ocean); this would concur with the findings of the Galileo magnetometer team. However, we cannot rule out the possibility that discrete liquid pockets provide injections of fluid closer to the surface.

Oceans in the Outer Solar System: Future Exploration of Europa, Titan, and Enceladus

NASA Astrophysics Data System (ADS)

Johnson, T.; Clark, K.; Cutts, J.; Lunine, J.; Pappalardo, R.; Reh, K.

Observational and theoretical evidence points to water-rich oceans or seas within several of the icy satellites of the outer planets, notably Europa and Enceladus, and hydrocarbon reservoirs within Titan. Here we report on concepts for future studies of these fascinating targets of high astrobiological relevance. Europa Exploration: Post-Galileo exploration of Europa presents several major technical challenges. We argue that four recent investments in technology and research allow a flagship mission class Europa exploration that relies on demonstrated technologies and achieves the high level science objectives. 1. Mass and Trip Time: Utilizing indirect Earth gravity assist, trajectories allows ˜2000 - 3000 kg dry mass, permitting ˜150 - 200 kg of science payload. 2. Radiation Tolerant Electronics: A significant program of radiation hard technology development has been done by NASA. The necessary radiation-tolerant elements are now ready for flight. 3. Science Mission: The science mission would last approximately two years, with a Jupiter system science phase of ˜1.5 yr and a 90 day nominal orbital mission at Europa, with significant probability of functioning much longer. 4. Planetary Protection: The ultimate fate of an orbiter will be impact with Europa. Planetary protection requirements will be met by radiation sterilization during the primary mission for most external and unshielded internal surfaces, combined with pre-launch sterilization of shielded components. We conclude that a flagship class Europa mission can now be developed relying on existing technologies, having significant scientific capability. Titan and Enceladus Exploration: Remarkable discoveries by the Cassini/Huygens related to hydrocarbons at Titan and water vapor geysering at Enceladus demand follow-up of these astrobiologically relevant worlds by future missions. An aerial platform capable of observing the surface of Titan from beneath the obscuring cloud cover and descending repeatedly to

Ganymede and Europa and their Jovian polar footprints

NASA Astrophysics Data System (ADS)

Sejkora, N.; Rucker, H. O.; Panchenko, M.

2017-09-01

The interactions between the Galilean moons Europa and Ganymede and the Jovian magnetosphere are studied. The focus lies on the satellites' auroral footprints observable in the polar regions of Jupiter. The work encompasses case studies of UV observations, obtained by the Hubble Space Telescope (HST), showing auroral features potentially triggered by either Europa or Ganymede. For those situations the footprint lead angles are determined, using different magnetic field models. The aim is to estimate the relationship between satellite longitude and lead angle. The delay between the local interaction at the satellite and the resulting auroral emission, which is implied by the obtained lead angles, is compared to the travel time of an Alfvén wave along a magnetic field line from the satellite to the planet.

Tether-mission design for multiple flybys of moon Europa

NASA Astrophysics Data System (ADS)

Sanmartin, J. R. S.; Charro, M. C.; Sanchez-Arriaga, G. S. A.; Sanchez-Torres, A. S. T.

2015-10-01

A tether mission to carry out multiple flybys of Jovian moon Europa is here presented. There is general agreement on elliptic-orbit flybys of Europa resulting in cost to attain given scientific goals lower than if actually orbiting the moon, tethers being naturally fit to fly-by rather than orbit moons1. The present mission is similar in this respect to the Clipper mission considered by NASA, the basic difference lying in location of periapsis, due to different emphasis on mission-challenge metrics. Clipper minimizes damaging radiation-dose by avoiding the Jupiter neighborhood and its very harsh environment; periapsis would be at Europa, apoapsis as far as moon Callisto. As in all past outer-planet missions, Clipper faces, however, critical power and propulsion needs. On the other hand, tethers can provide both propulsion and power, but must reach near the planet to find high plasma density and magnetic field values, leading to high induced tether current, and Lorentz drag and power. The bottom line is a strong radiation dose under the very intense Radiation Belts of Jupiter. Mission design focuses on limiting dose. Perijove would be near Jupiter, at about 1.2-1.3 Jovian radius, apojove about moon Ganymede, corresponding to 1:1 resonance with Europa, so as to keep dose down: setting apojove at Europa, for convenient parallel flybys, would require two perijove passes per flyby (the Ganymede apojove, resulting in high eccentricity, about 0.86, is also less requiring on tether operations). Mission is designed to attain reductions in eccentricity per perijove pass as high as Δe ≈ - 0.04. Due the low gravity-gradient, tether spinning is necessary to keep it straight, plasma contactors placed at both ends taking active turns at being cathodic. Efficiency of capture of the incoming S/C by the tether is gauged by the ratio of S/C mass to tether mass; efficiency is higher for higher tape-tether length and lower thickness and perijove. Low tether bowing due to the Lorentz

JIRAM infrared observations of Jupiter Aurorae: results of the first year.

NASA Astrophysics Data System (ADS)

Mura, A.; Adriani, A.; Altieri, F.; Dinelli, B. M.; Moriconi, M. L.; Migliorini, A.; Bolton, S. J.; Connerney, J. E. P.; Cicchetti, A.; Noschese, R.; Sindoni, G.; Tosi, F.; Filacchione, G.; Fabiano, F.; Piccioni, G.; Turrini, D.; Amoroso, M.; Plainaki, C.; Olivieri, A.; Gerard, J.-C.

2017-09-01

JIRAM (Jovian Infrared Auroral Mapper) is an imaging spectrometer on board the Juno spacecraft, specifically designed to observe the aurorae of Jupiter. Here we show results on JIRAM's data after one year of observations. The footprints of Io, Europa and Ganymede have also been observed and characterized.

Europa Small Lander Design Concepts

NASA Astrophysics Data System (ADS)

Zimmerman, W. F.

2005-12-01

Title: Europa Small Lander Design Concepts Authors: Wayne F. Zimmerman, James Shirley, Robert Carlson, Tom Rivellini, Mike Evans One of the primary goals of NASA's Outer Planets Program is to revisit the Jovian system. A new Europa Geophysical Explorer (EGE) Mission has been proposed and is under evaluation. There is in addition strong community interest in a surface science mission to Europa. A Europa Lander might be delivered to the Jovian system with the EGE orbiter. A Europa Astrobiology Lander (EAL) Mission has also been proposed; this would launch sometime after 2020. The primary science objectives for either of these would most likely include: Surface imaging (both microscopic and near-field), characterization of surface mechanical properties (temperature, hardness), assessment of surface and near-surface organic and inorganic chemistry (volatiles, mineralogy, and compounds), characterization of the radiation environment (total dose and particles), characterization of the planetary seismicity, and the measurement of Europa's magnetic field. The biggest challenges associated with getting to the surface and surviving to perform science investigations revolve around the difficulty of landing on an airless body, the ubiquitous extreme topography, the harsh radiation environment, and the extreme cold. This presentation reviews some the recent design work on drop-off probes, also called "hard landers". Hard lander designs have been developed for a range of science payload delivery systems spanning small impactors to multiple science pods tethered to a central hub. In addition to developing designs for these various payload delivery systems, significant work has been done in weighing the relative merits of standard power systems (i.e., batteries) against radioisotope power systems. A summary of the power option accommodation benefits and issues will be presented. This work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under a

Geological evidence for solid-state convection in Europa's ice shell.

PubMed

Pappalardo, R T; Head, J W; Greeley, R; Sullivan, R J; Pilcher, C; Schubert, G; Moore, W B; Carr, M H; Moore, J M; Belton, M J; Goldsby, D L

1998-01-22

The ice-rich surface of the jovian satellite Europa is sparsely cratered, suggesting that this moon might be geologically active today. Moreover, models of the satellite's interior indicate that tidal interactions with Jupiter might produce enough heat to maintain a subsurface liquid water layer. But the mechanisms of interior heat loss and resurfacing are currently unclear, as is the question of whether Europa has (or had at one time) a liquid water ocean. Here we report on the morphology and geological interpretation of distinct surface features-pits, domes and spots-discovered in high-resolution images of Europa obtained by the Galileo spacecraft. The features are interpreted as the surface manifestation of diapirs, relatively warm localized ice masses that have risen buoyantly through the subsurface. We find that the formation of the features can be explained by thermally induced solid-state convection within an ice shell, possibly overlying a liquid water layer. Our results are consistent with the possibility that Europa has a liquid water ocean beneath a surface layer of ice, but further tests and observations are needed to demonstrate this conclusively.

Geological evidence for solid-state convection in Europa's ice shell

USGS Publications Warehouse

Pappalardo, R.T.; Head, J.W.; Greeley, R.; Sullivan, R.J.; Pilcher, C.; Schubert, G.; Moore, W.B.; Carr, M.H.; Moore, Johnnie N.; Belton, M.J.S.; Goldsby, D.L.

1998-01-01

The ice-rich surface of the jovian satellite Europa is sparsely cratered, suggesting that this moon might be geologically active today. Moreover, models of the satellite's interior indicate that tidal interactions with Jupiter might produce enough heat to maintain a subsurface liquid water layer. But the mechanisms of interior heat loss and resurfacing are currently unclear, as is the question of whether Europa has (or had at one time) a liquid water ocean. Here we report on the morphology and geological interpretation of distinct surface features-pits, domes and spots-discovered in high-resolution images of Europa obtained by the Galileo spacecraft. The features are interpreted as the surface manifestation of diapirs, relatively warm localized ice masses that have risen buoyantly through the subsurface. We find that the formation of the features can be explained by thermally induced solid-state convection within an ice shell, possibly overlying a liquid water layer. Our results are consistent with the possibility that Europa has a liquid water ocean beneath a surface layer of ice, but further tests and observations are needed to demonstrate this conclusively.

Astrobiology of Jupiter's icy moons

NASA Astrophysics Data System (ADS)

Lipps, Jere H.; Delory, Gregory; Pitman, Joseph T.; Rieboldt, Sarah

2004-11-01

Jupiter's Icy Moons, Europa, Ganymede and Callisto, may possess energy sources, biogenic molecules, and oceans below their icy crusts, thus indicating a strong possibility that they were abodes for present or past life. Life in Earth's icy areas lives in a wide variety of habitats associated with the ice, in the water column below the ice, and on the floor of the ocean below the ice. Similar habitats may exist on JIM, have been transported to the icy crust, and be exposed in tectonic or impact features. Europa has a young, dynamic surface with many outcrops exposing older ice, fresh ice, possible materials from the subsurface ocean, and a few impact craters. Ganymede has older, darker, tectonized terrains surrounded by light ice. Callisto has a much older, heavily impacted surface devoid of significant tectonic structures. Past and present life habitats may be exposed in these features, making Europa the most favorable target while Ganymede is of interest, and Callisto seems more unlikely to have detectable life. A proper search strategy requires detailed orbital imaging and spectrometry of the likely places, and surface data collection with microscopic, spectrometric, and biochemical instruments.

Jupiter Blues

NASA Image and Video Library

2017-11-30

See Jovian clouds in striking shades of blue in this new view taken by NASA's Juno spacecraft. The Juno spacecraft captured this image when the spacecraft was only 11,747 miles (18,906 kilometers) from the tops of Jupiter's clouds -- that's roughly as far as the distance between New York City and Perth, Australia. The color-enhanced image, which captures a cloud system in Jupiter's northern hemisphere, was taken on Oct. 24, 2017 at 10:24 a.m. PDT (1:24 p.m. EDT) when Juno was at a latitude of 57.57 degrees (nearly three-fifths of the way from Jupiter's equator to its north pole) and performing its ninth close flyby of the gas giant planet. The spatial scale in this image is 7.75 miles/pixel (12.5 kilometers/pixel). Because of the Juno-Jupiter-Sun angle when the spacecraft captured this image, the higher-altitude clouds can be seen casting shadows on their surroundings. The behavior is most easily observable in the whitest regions in the image, but also in a few isolated spots in both the bottom and right areas of the image. Citizen scientists Gerald Eichstädt and Seán Doran processed this image using data from the JunoCam imager. https://photojournal.jpl.nasa.gov/catalog/PIA21972

Jupiter Hot Spot

NASA Image and Video Library

2001-01-03

In this movie clip (of which the release image is a still frame), created from images taken by NASA's Cassini spacecraft, the blue region in the center is a relatively cloud-free area where thermal radiation from warmer, deeper levels emerges. NASA's Galileo probe in 1995 entered Jupiter's atmosphere in a similar area. http://photojournal.jpl.nasa.gov/catalog/PIA02875

Simulation of Europa's water plume .

NASA Astrophysics Data System (ADS)

Lucchetti, A.; Cremonese, G.; Schneider, N. M.; Plainaki, C.; Mazzotta Epifani, E.; Zusi, M.; Palumbo, P.

Plumes on Europa would be extremely interesting science and mission targets, particularly due to the unique opportunity to obtain direct information on the subsurface composition, thereby addressing Europa's potential habitability. The existence of water plume on the Jupiter's moon Europa has been long speculated until the recent discover. HST imaged surpluses of hydrogen Lyman alpha and oxygen emissions above the southern hemisphere in December 2012 that are consistent with two 200 km high plumes of water vapor (Roth et al. 2013). In previous works ballistic cryovolcanism has been considered and modeled as a possible mechanism for the formation of low-albedo features on Europa's surface (Fagents et al. 2000). Our simulation agrees with the model of Fagents et al. (2000) and consists of icy particles that follow ballistic trajectories. The goal of such an analysis is to define the height, the distribution and the extension of the icy particles falling on the moon's surface as well as the thickness of the deposited layer. We expect to observe high albedo regions in contrast with the background albedo of Europa surface since we consider that material falling after a cryovolcanic plume consists of snow. In order to understand if this phenomenon is detectable we convert the particles deposit in a pixel image of albedo data. We consider also the limb view of the plume because, even if this detection requires optimal viewing geometry, it is easier detectable in principle against sky. Furthermore, we are studying the loss rates due to impact electron dissociation and ionization to understand how these reactions decrease the intensity of the phenomenon. We expect to obtain constraints on imaging requirements necessary to detect potential plumes that could be useful for ESA's JUICE mission, and in particular for the JANUS camera (Palumbo et al. 2014).

Jupiter

NASA Image and Video Library

1998-06-04

This processed color image of Jupiter was produced in 1990 by the U.S. Geological Survey from a Voyager image captured in 1979. Zones of light-colored, ascending clouds alternate with bands of dark, descending clouds. http://photojournal.jpl.nasa.gov/catalog/PIA00343

Jupiter's Colorful Cloud Belts

NASA Image and Video Library

2018-01-12

Colorful swirling cloud belts dominate Jupiter's southern hemisphere in this image captured by NASA's Juno spacecraft. Jupiter appears in this color-enhanced image as a tapestry of vibrant cloud bands and storms. The dark region in the far left is called the South Temperate Belt. Intersecting the belt is a ghost-like feature of slithering white clouds. This is the largest feature in Jupiter's low latitudes that's a cyclone (rotating with clockwise motion). This image was taken on Dec. 16, 2017 at 10:12 PST (1:12 p.m. EST), as Juno performed its tenth close flyby of Jupiter. At the time the image was taken, the spacecraft was about 8,453 miles (13,604 kilometers) from the tops of the clouds of the planet at a latitude of 27.9 degrees south. The spatial scale in this image is 5.6 miles/pixel (9.1 kilometers/pixel). Citizen scientist Kevin M. Gill processed this image using data from the JunoCam imager. https://photojournal.jpl.nasa.gov/catalog/PIA21974

Jupiter Temperatures

NASA Image and Video Library

1997-09-29

This is one of the highest resolution images ever recorded of Jupiter temperature field. It was obtained by NASA Galileo mission. This map, shown in the lower panel, indicates the forces powering Jovian winds.

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

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

Europa Linear Features from 246,000 kilometers

NASA Technical Reports Server (NTRS)

1979-01-01

The first close look ever obtained of Jupiter's satellite, Europa, was taken today, July 9, by Voyager 2 as the spacecraft approached the planet. The linear crack-like features had been seen from a much greater distance last March by Voyager 1. This picture was made at a range of 246,000 kilometers (152,000 miles) and provides a resolution of about four kilometers (2.5 miles). The complicated linear features appear even more like cracks or huge fractures in these images. Also seen are somewhat darker mottled regions which appear to have a slightly pitted appearance, perhaps due to small scale craters. No large craters (more than five kilometers in diameter) are easily identifiable in the Europa photographs to date, suggesting that this satellite has a young surface relative to Ganymede and Callisto, although not perhaps as young as Io's. Various models for Europa's structure will be tested during analysis of these images, including the possibility that the surface is a thin ice crust overlying water or softer ice and that the fracture systems seen are breaks in that crust. Resurfacing mechanisms such as production of fresh ice or snow along the cracks and cold glacier-like flows are being considered as possibilities for removing evidence of impact events. Europa thus appears to truly be a satellite with many properties intermediate between Ganymede and Io.

Sputtering and detection of large organic molecules from Europa

NASA Astrophysics Data System (ADS)

Johnson, R. E.; Sundqvist, B. U. R.

2018-07-01

Mass spectroscopy of bio-molecules by heavy ion induced sputtering, which became a practical laboratory procedure, was also suggested as a potential tool for spacecraft studies of targets of interest in astrobiology. With the planning of new missions to Europa, there is renewed interest in the possibility of detecting organic molecules that might have originated in its subsurface ocean and can be sputtered from its surface often intact by impacting energetic heavy ions trapped in Jupiter's magnetosphere. Here we review the laboratory data and modeling bearing on this issue. We then give estimates of the ejection into the gas-phase of trace organic species embedded in an ice matrix on Europa's surface and their possible detection during a flyby mission.

Jupiter Red 'Monet'

NASA Image and Video Library

2017-08-30

Citizen scientist David Englund created this avant-garde Jovian artwork using data from the JunoCam imager on NASA's Juno spacecraft. The unique interpretation of Jupiter's Great Red Spot was done in a style that pays tribute to French Impressionist painter Claude Monet. The original image was taken on July 10, 2017 at 7:12 p.m. PDT (10:12 p.m. EDT), as the Juno spacecraft performed its 7th close flyby of Jupiter. At the time the image was taken, the spacecraft was 10,274 miles (16,535 kilometers) from the tops of the clouds of the planet, at a latitude of -36.9 degrees. https://photojournal.jpl.nasa.gov/catalog/PIA21779

Rose-Colored Jupiter

NASA Image and Video Library

2018-03-15

This image captures a close-up view of a storm with bright cloud tops in the northern hemisphere of Jupiter. NASA's Juno spacecraft took this color-enhanced image on Feb. 7 at 5:38 a.m. PST (8:38 a.m. EST) during its 11th close flyby of the gas giant planet. At the time, the spacecraft was 7,578 miles (12,195 kilometers) from the tops of Jupiter's clouds at 49.2 degrees north latitude. Citizen scientist Matt Brealey processed the image using data from the JunoCam imager. Citizen scientist Gustavo B C then adjusted colors and embossed Matt Brealey's processing of this storm. https://photojournal.jpl.nasa.gov/catalog/PIA21981

Jupiter Ring

NASA Image and Video Library

2000-03-23

First evidence of a ring around the planet Jupiter is seen in this photograph taken by Voyager 1 on March 4, 1979. The multiple exposure of the extremely thin faint ring appears as a broad light band crossing the center of the picture. The edge of the ring is 1,212,000 km from the spacecraft and 57,000 km from the visible cloud deck of Jupiter. The background stars look like broken hair pins because of spacecraft motion during the 11 minute 12 second exposure. The wavy motion of the star trails is due to the ultra-slow natural oscillation of the spacecraft (with a period of 78 seconds). The black dots are geometric calibration points in the camera. The ring thickness is estimated to be 30 km or less. The photograph was part of a sequence planned to search for such rings in Jupiter's equatorial plane. The ring has been invisible from Earth because of its thinness and its transparency when viewed at any angle except straight on. JPL manages and controls the Voyager Project for NASA's Office of Space Science. http://photojournal.jpl.nasa.gov/catalog/PIA02251

Jupiter's Stormy North

NASA Image and Video Library

2018-01-25

See Jupiter's northern polar belt region in this view taken by NASA's Juno spacecraft. This color-enhanced image was taken on Dec. 16, 2017 at 9:47 a.m. PST (12:47 p.m. EST), as Juno performed its tenth close flyby of Jupiter. At the time the image was taken, the spacecraft was about 5,600 miles (8,787 kilometers) from the tops of the clouds of the planet at a latitude of 38.4 degrees north. Citizen scientist Björn Jónsson processed this image using data from the JunoCam imager. This image has been processed from the raw JunoCam framelets by removing the effects of global illumination. Jónsson then increased the contrast and color and sharpened smallscale features. The image has also been cropped. While at first glance the view may appear to be in Jupiter's south, the raw source images were obtained when Juno was above the planet's northern hemisphere looking south, potentially causing a sense of disorientation to the viewer. The geometry of the scene can be explored using the time of the image and the Juno mission module of NASA's Eyes on the Solar System. https://photojournal.jpl.nasa.gov/catalog/PIA21976

Heat transfer of ascending cryomagma on Europa

NASA Astrophysics Data System (ADS)

Quick, Lynnae C.; Marsh, Bruce D.

2016-06-01

Jupiter's moon Europa has a relatively young surface (60-90 Myr on average), which may be due in part to cryovolcanic processes. Current models for both effusive and explosive cryovolcanism on Europa may be expanded and enhanced by linking the potential for cryovolcanism at the surface to subsurface cryomagmatism. The success of cryomagma transport through Europa's crust depends critically on the rate of ascent relative to the rate of solidification. The final transport distance of cryomagma is thus governed by initial melt volume, ascent rate, overall ascent distance, transport mechanism (i.e., diapirism, diking, or ascent in cylindrical conduits), and melt temperature and composition. The last two factors are especially critical in determining the budget of expendable energy before complete solidification. Here we use these factors as constraints to explore conditions under which cryomagma may arrive at Europa's surface to facilitate cryovolcanism. We find that 1-5 km radius warm ice diapirs ascending from the base of a 10 km thick stagnant lid can reach the shallow subsurface in a partially molten state. Cryomagma transport may be further facilitated if diapirs travel along pre-heated ascent paths. Under certain conditions, cryolava transported from 10 km depths in tabular dikes or pipe-like conduits may reach the surface at temperatures exceeding 250 K. Ascent rates for these geometries may be high enough that isothermal transport is approached. Cryomagmas containing significant amounts of low eutectic impurities can also be delivered to Europa's surface by propagating dikes or pipe-like conduits.

Design of human missions to Mars and robotic missions to Jupiter

NASA Astrophysics Data System (ADS)

Okutsu, Masataka

We consider human missions to Mars and robotic missions to Jupiter for launch dates in the near- and far-future. For the near-future, we design trajectories for currently proposed space missions that have well-defined spacecraft and mission requirements. For example, for early human missions to Mars we assume that the constraints used in NASA's design reference missions are indicative of current and near-future technologies, which of course limit our capabilities to explore Mars--and these limits make the problem challenging. Similarly, in the case of robotic exploration of Jupiter, we consider that the technology levels assumed for the proposed Europa Orbiter mission represent reasonable limits. For the far-future (two to three decades from now), we take the best estimates from current literature about the capabilities that may be available in nuclear-powered electric propulsion. We consider hardware capabilities (in terms of specific mass, specific impulse, thrust, power, etc.) for low-thrust trajectories, which range froth near-term to far-future technologies. In designing such missions, several techniques are found useful. For example, the Tisserand Graph, which tracks the changes in orbital shapes and energies, provides insight in designing Jovian tours for the Europa Orbiter mission. The graph is also useful in analyzing abort trajectories for human missions to Mars. Furthermore, a patched-conic propagator, which can generate thousands of potential trajectories, plays a vital role in three of four chapters of this thesis. For launches in the next three decades, we discovered a class of Earth- Mars-Venus-Earth free returns (which appear only four times in the 100-year period), Jovian tours involving ten to twenty flybys of the Galilean satellites, and low-thrust trajectories to Jupiter via gravity assists from Venus, Earth, and Mars. In addition, our continuation method, in which a solution for a conic trajectory is gradually converted into that for a low

Main magnetic field of Jupiter and its implications for future orbiter missions

NASA Technical Reports Server (NTRS)

Acuna, M. H.; Ness, N. F.

1975-01-01

A very strong planetary magnetic field and an enormous magnetosphere with extremely intense radiation belts exist at Jupiter. Pioneer 10 and 11 fly-bys confirmed and extended the earlier ground based estimates of many of these characteristics but left unanswered or added to the list of several important and poorly understood features: the source mechanism and location of decametric emissions, and the absorption effects by the natural satellites Amalthea, Io, Europa and Ganymede. High inclination orbits (exceeding 60 deg) with low periapses (less than 2 Jupiter radii) are required to map the radiation belts and main magnetic field of Jupiter accurately so as to permit full investigation of these and associated phenomena.

Gravity results from Pioneer 10 Doppler data. [during Jupiter encounter

NASA Technical Reports Server (NTRS)

Anderson, J. D.; Null, G. W.; Wong, S. K.

1974-01-01

Two-way Doppler data received from Pioneer 10 during its encounter with Jupiter have been analyzed, and preliminary results have been obtained on the mass and the gravity field of Jupiter and on the masses of the four Galilean satellites. The ratios of the masses of the satellites to the mass of Jupiter are approximately 0.00004696 for Io, 0.00002565 for Europa, 0.00007845 for Ganymede, and 0.00005603 for Callisto (all error estimates presented in this paper are standard errors; those for Pioneer 10 represent our evaluation of the real errors as distinguished from formal errors). The ratio of the mass of the sun to the mass of the Jupiter system is about 1047.342, which is in good agreement with recent determinations from the motions of asteroids. The second- and fourth-degree zonal harmonic coefficients in the gravity field of Jupiter are 0.014720 and -0.00065, respectively, based on an equatorial planetary radius of 71,400 km, and the derived dynamical oblateness is 0.0647 at the same radius. The Pioneer 10 data are consistent with the assumption that Jupiter is in hydrostatic equilibrium at all levels.

Jupiter and Its Galilean Satellites

NASA Technical Reports Server (NTRS)

McGrath, Melissa A.

2012-01-01

Jupiter is one of the two most studied planets other than Earth in our Solar System. It is the largest, fastest rotating, has the strongest magnetic field, and an incredibly diverse set of satellites, most prominent of which are the four Galilean satellites discovered in 1610. Io, Europa, Ganymede and Callisto encompass some of the most bizarre environments known in the solar system, from Io, the most volcanically active and perhaps the most inhospitable body known, to Europa, currently thought to be the most likely extraterrestrial abode for habitability, to Ganymede, which is larger than Mercury, and Callisto, which has the oldest surface known in the solar system with the widest array of crater morphologies known. One of the premier areas of scientific return in solar system research in the past 15 years, due in large part to the Galileo mission and observations by the Hubble Space Telescope, has been a remarkable increase in our knowledge about these satellites. Discoveries have been made of tenuous molecular oxygen atmospheres on Europa and Ganymede, a magnetic field and accompanying auroral emissions at the poles of Ganymede, and of ozone and sulfur dioxide embedded in the surfaces of Europa, Ganymede and Callisto. Io's unusual sulfur dioxide atmosphere, including its volcanic plumes and strong electrodynamic interaction with magnetospheric plasma, has finally been quantitatively characterized. This talk will present highlights from the recent discoveries and advances in our understanding of these fascinating objects.

Jupiter's Bands of Clouds

NASA Image and Video Library

2017-06-22

This enhanced-color image of Jupiter's bands of light and dark clouds was created by citizen scientists Gerald Eichstädt and Seán Doran using data from the JunoCam imager on NASA's Juno spacecraft. Three of the white oval storms known as the "String of Pearls" are visible near the top of the image. Each of the alternating light and dark atmospheric bands in this image is wider than Earth, and each rages around Jupiter at hundreds of miles (kilometers) per hour. The lighter areas are regions where gas is rising, and the darker bands are regions where gas is sinking. Juno acquired the image on May 19, 2017, at 11:30 a.m. PST (2:30 p.m. EST) from an altitude of about 20,800 miles (33,400 kilometers) above Jupiter's cloud tops. https://photojournal.jpl.nasa.gov/catalog/PIA21393

Orbital apocenter is not a sufficient condition for HST/STIS detection of Europa's water vapor aurora.

PubMed

Roth, Lorenz; Retherford, Kurt D; Saur, Joachim; Strobel, Darrell F; Feldman, Paul D; McGrath, Melissa A; Nimmo, Francis

2014-12-02

We report far-ultraviolet observations of Jupiter's moon Europa taken by Space Telescope Imaging Spectrograph (STIS) of the Hubble Space Telescope (HST) in January and February 2014 to test the hypothesis that the discovery of a water vapor aurora in December 2012 by local hydrogen (H) and oxygen (O) emissions with the STIS originated from plume activity possibly correlated with Europa's distance from Jupiter through tidal stress variations. The 2014 observations were scheduled with Europa near the apocenter similar to the orbital position of its previous detection. Tensile stresses on south polar fractures are expected to be highest in this orbital phase, potentially maximizing the probability for plume activity. No local H and O emissions were detected in the new STIS images. In the south polar region where the emission surpluses were observed in 2012, the brightnesses are sufficiently low in the 2014 images to be consistent with any H2O abundance from (0-5)×10(15) cm(-2). Large high-latitude plumes should have been detectable by the STIS, independent of the observing conditions and geometry. Because electron excitation of water vapor remains the only viable explanation for the 2012 detection, the new observations indicate that although the same orbital position of Europa for plume activity may be a necessary condition, it is not a sufficient condition. However, the December 2012 detection of coincident HI Lyman-α and OI 1304-Å emission surpluses in an ∼200-km high region well separated above Europa's limb is a firm result and not invalidated by our 2014 STIS observations.

Orbital apocenter is not a sufficient condition for HST/STIS detection of Europa's water vapor aurora

NASA Astrophysics Data System (ADS)

Roth, Lorenz; Retherford, Kurt D.; Saur, Joachim; Strobel, Darrell F.; Feldman, Paul D.; McGrath, Melissa A.; Nimmo, Francis

2014-12-01

We report far-ultraviolet observations of Jupiter's moon Europa taken by Space Telescope Imaging Spectrograph (STIS) of the Hubble Space Telescope (HST) in January and February 2014 to test the hypothesis that the discovery of a water vapor aurora in December 2012 by local hydrogen (H) and oxygen (O) emissions with the STIS originated from plume activity possibly correlated with Europa's distance from Jupiter through tidal stress variations. The 2014 observations were scheduled with Europa near the apocenter similar to the orbital position of its previous detection. Tensile stresses on south polar fractures are expected to be highest in this orbital phase, potentially maximizing the probability for plume activity. No local H and O emissions were detected in the new STIS images. In the south polar region where the emission surpluses were observed in 2012, the brightnesses are sufficiently low in the 2014 images to be consistent with any H2O abundance from (0-5)×1015 cm-2. Large high-latitude plumes should have been detectable by the STIS, independent of the observing conditions and geometry. Because electron excitation of water vapor remains the only viable explanation for the 2012 detection, the new observations indicate that although the same orbital position of Europa for plume activity may be a necessary condition, it is not a sufficient condition. However, the December 2012 detection of coincident HI Lyman-α and OI 1304-Å emission surpluses in an ∼200-km high region well separated above Europa's limb is a firm result and not invalidated by our 2014 STIS observations.

Science potential from a Europa lander.

PubMed

Pappalardo, R T; Vance, S; Bagenal, F; Bills, B G; Blaney, D L; Blankenship, D D; Brinckerhoff, W B; Connerney, J E P; Hand, K P; Hoehler, T M; Leisner, J S; Kurth, W S; McGrath, M A; Mellon, M T; Moore, J M; Patterson, G W; Prockter, L M; Senske, D A; Schmidt, B E; Shock, E L; Smith, D E; Soderlund, K M

2013-08-01

The prospect of a future soft landing on the surface of Europa is enticing, as it would create science opportunities that could not be achieved through flyby or orbital remote sensing, with direct relevance to Europa's potential habitability. Here, we summarize the science of a Europa lander concept, as developed by our NASA-commissioned Science Definition Team. The science concept concentrates on observations that can best be achieved by in situ examination of Europa from its surface. We discuss the suggested science objectives and investigations for a Europa lander mission, along with a model planning payload of instruments that could address these objectives. The highest priority is active sampling of Europa's non-ice material from at least two different depths (0.5-2 cm and 5-10 cm) to understand its detailed composition and chemistry and the specific nature of salts, any organic materials, and other contaminants. A secondary focus is geophysical prospecting of Europa, through seismology and magnetometry, to probe the satellite's ice shell and ocean. Finally, the surface geology can be characterized in situ at a human scale. A Europa lander could take advantage of the complex radiation environment of the satellite, landing where modeling suggests that radiation is about an order of magnitude less intense than in other regions. However, to choose a landing site that is safe and would yield the maximum science return, thorough reconnaissance of Europa would be required prior to selecting a scientifically optimized landing site.

Jupiter with Io Crossing

NASA Image and Video Library

1996-09-26

million kilometers). The satellite's shadow can be seen falling on the face of Jupiter at left. Io is traveling from left to right in its one-and-three-quarter-day orbit around Jupiter. Even from this great distance the image of Io shows dark poles and a bright equatorial region. Voyager will make its closest approach to Jupiter -- 174,000 miles (280,000 kilometer) -- on March 5. It will then continue to Saturn in November 1980, Meanwhile Voyager 2, a sister spacecraft, will fly past Jupiter July 9, 1979, and reach Saturn in August 1981. This color image was taken through orange, green and blue filters. http://photojournal.jpl.nasa.gov/catalog/PIA00455

Jupiter's Main Ring

NASA Technical Reports Server (NTRS)

1997-01-01

A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (km) per picture element (pixel) along the rings; however, because the spacecraft was only about 0.5 degrees above the ring plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow peering back toward the Sun; the ring was approximately 2,300,000 kilometers (km) away. The arc on the far right of the image is produced by sunlight scattered by small particles comprising Jupiter's upper atmospheric haze. The ring also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age.

Jupiter's ring system is composed of three parts -- a flat main ring, a lenticular halo interior to the main ring, and the gossamer ring, which lies exterior to the main ring. The near and far arms of Jupiter's main ring extend horizontally across the mosaic, joining together at the ring's ansa, on the far left side of the figure. The near arm of the ring appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow. Some radial structure is barely visible across the ring's ansa. A faint mist of particles can be seen above and below the main rings; this vertically extended 'halo' is unusual in planetary rings, and is probably caused by electromagnetic forces pushing the smallest grains out of the ring plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic.

Jupiter's main ring is a thin strand of material encircling the planet. The diffuse innermost boundary begins at approximately 123,000 km. The main ring's outer radius is found to be

Jupiter's Great Red Spot Revealed

NASA Image and Video Library

2017-07-12

This enhanced-color image of Jupiter's Great Red Spot was created by citizen scientist Kevin Gill using data from the JunoCam imager on NASA's Juno spacecraft. The image was taken on July 10, 2017 at 07:07 p.m. PDT (10:07 p.m. EDT), as the Juno spacecraft performed its 7th close flyby of Jupiter. At the time the image was taken, the spacecraft was about 6,130 miles (9,866 kilometers) from the tops of the clouds of the planet. https://photojournal.jpl.nasa.gov/catalog/PIA21395

Europa Science Platforms and Kinetic Energy Probes

NASA Technical Reports Server (NTRS)

Hays, C. C.; Klein, G. A.

2003-01-01

This presentation will outline a proposed mission for the Jupiter Icy Moons Orbiter (JIMO). The mission outlined will concentrate on an examination of Europa. Some of the primary science goals for the JIMO mission are: 1) to answer broad science questions, 2) improved knowledge of Jovian system; specifically, lunar geological and geophysical properties, 3) chemical composition of Jovian lunar surfaces and subterranean matter, and 4) the search for life. In order to address these issues, the experiment proposed here will deploy orbiting, surface, and subterranean science platforms.

Can a future mission detect a habitable ecosystem on Europa, or Ganymede?

NASA Astrophysics Data System (ADS)

Chela Flores, Julian

2010-05-01

habitable ecosystem has emerged on Europa. The test is well within reach of available technology that is needed for planning the eventual penetrator payload. References (*) Bland, M. T. et al. (2009) The orbital-thermal evolution and global expansion of Ganymede. Icarus 200, 207-221. Carlson, R. W. et al. (1999) Sulfuric Acid on Europa and the Radiolytic Sulfur Cycle. Science 286, 97-99. Chela-Flores, J. (2010) Instrumentation for the search of habitable ecosystems in the future exploration of Europa and Ganymede. International Journal of Astrobiology, in press. http://www.ictp.it/chelaf/jcfSeamless.pdf Gowen, R. et al. (2009) Looking for Astrobiological Signatures with Penetrators on Europa. Physical and Engineering Sciences Exploratory Workshops, Abstracts, Mulhouse, France. http://www.ictp.it/chelaf/ESFsummary.pdf Grasset, O. et al. (2009) "The Jupiter Ganymede Orbiter as part of the ESA/NASA Europa Jupiter System Mission (EJSM),EPSC Abstracts, 4: EPSC2009-784, European Planetary Science Congress. Kiyosu, Y. and Krouse, H.R. (1990) The role of organic acid in the abiogenic reduction of sulfate and the sulfur isotope effect. Geochemical Journal 24, 21-27. McCord et al. (1997) Organics and Other Molecules in the Surfaces of Callisto and Ganymede. Science 278, 271 - 275. McCord, T. B. et al. (1999) Hydrated salt minerals on Europa's Surface from the Galileo near-infrared mapping spectrometer (NIMS) investigation. J. Geophys. Res. 104, 11827-11851. Shen, Y. and Buick, R. (2004) The antiquity of microbial sulfate reduction. Earth-Science Reviews 64, 243-272. Wortmann, U.G. et al. (2001) Hypersulfidic deep biosphere indicates extreme sulfur isotope fractionation during single-step microbial sulfate reduction. Geology 29, 647-650. (*) Please notice that in both website references to the Academic Page of the author, the reader should insert the symbol twiddle in front of chelaf.

Europa's Icy Shell: A Bridge Between Its Surface and Ocean

NASA Technical Reports Server (NTRS)

Schenk, Paul; Mimmo, Francis; Prockter, Louise

2004-01-01

Europa, a Moon-sized, ice-covered satellite of Jupiter, is second only to Mars in its astrobiological potential. Beneath the icy surface, an ocean up to 150 km deep is thought to exist, providing a potential habitat for life,and a tempting target for future space missions. The Galileo mission to the Jovian system recently ended, but there are already long-range plans to send much more capable spacecraft,such as the proposed Jupiter Icy Moons Orbiter (JIMO), to take a closer look at Europa and her siblings, Ganymede and Callisto, some time in the next two decades. Europak outer icy shell is the only interface between this putative ocean and the surface, but many aspects of this shell are presently poorly understood; in particular, its composition, thickness, deformational history, and mechanical properties. To discuss the ice shell and our current understanding of it, 78 scientists from the terrestrial and planetary science communities in the United States and Europe gathered for a 3-day workshop hosted by the Lunar and Planetary Institute in Houston in February. A key goal was to bring researchers from disparate disciplines together to discuss the importance and limitations of available data on Europa with a post-Galileo perspective. The workshop featured 2 days of reviews and contributed talks on the composition, physical properties, stratigraphy, tectonics, and future exploration of the ice shell and underlying ocean. The final morning included an extended discussion period, moderated by a panel of noted experts, highlighting outstanding questions and areas requiring future research.

The Galilean satellites.

PubMed

Showman, A P; Malhotra, R

1999-10-01

NASA's Galileo mission to Jupiter and improved Earth-based observing capabilities have allowed major advances in our understanding of Jupiter's moons Io, Europa, Ganymede, and Callisto over the past few years. Particularly exciting findings include the evidence for internal liquid water oceans in Callisto and Europa, detection of a strong intrinsic magnetic field within Ganymede, discovery of high-temperature silicate volcanism on Io, discovery of tenuous oxygen atmospheres at Europa and Ganymede and a tenuous carbon dioxide atmosphere at Callisto, and detection of condensed oxygen on Ganymede. Modeling of landforms seen at resolutions up to 100 times as high as those of Voyager supports the suggestion that tidal heating has played an important role for Io and Europa.

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

Intricate Clouds of Jupiter

NASA Image and Video Library

2018-04-06

See intricate cloud patterns in the northern hemisphere of Jupiter in this new view taken by NASA's Juno spacecraft. The color-enhanced image was taken on April 1, 2018 at 2:32 a.m. PST (5:32 a.m. EST), as Juno performed its twelfth close flyby of Jupiter. At the time the image was taken, the spacecraft was about 7,659 miles (12,326 kilometers) from the tops of the clouds of the planet at a northern latitude of 50.2 degrees. Citizen scientist Kevin M. Gill processed this image using data from the JunoCam imager. https://photojournal.jpl.nasa.gov/catalog/PIA21984

Jupiter's Swirling Cloud Formations

NASA Image and Video Library

2018-02-15

See swirling cloud formations in the northern area of Jupiter's north temperate belt in this new view taken by NASA's Juno spacecraft. The color-enhanced image was taken on Feb. 7 at 5:42 a.m. PST (8:42 a.m. EST), as Juno performed its eleventh close flyby of Jupiter. At the time the image was taken, the spacecraft was about 5,086 miles (8,186 kilometers) from the tops of the clouds of the planet at a latitude of 39.9 degrees. Citizen scientist Kevin M. Gill processed this image using data from the JunoCam imager. https://photojournal.jpl.nasa.gov/catalog/PIA21978

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

NASA Technical Reports Server (NTRS)

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

2011-01-01

The magnetospheric ion population of Jupiter is dominated by the 1000 kg/s of iogenic material constantly ejected by IO volcanism as neutral gas (approx. 1 kg/s goes out as high speed dust grains), subsequent atmospheric losses to the IO torus, and radial transport of torus ions throughout the magnetosphere. As that magnetosphere is greatly distended in radial size by the iogenic plasma loading, so are surfaces of the other Galilean moons also significantly, and perhaps even dominantly, affected by iogenic plasma bombardment, e.g. at the level up to 0.2 kg/s heavy ions (mostly O and S) onto Europa as per local plasma ion measurements. In comparison, cometary impacts onto IO deliver about 0.02 kg/s of impact ejecta to Europa via ballistic transfer through the Jupiter system. The magnetosphere of this system operates as a powerful engine to produce and transport ions from the IO source to the surfaces of these other moons, and any future orbiter missions to these moons must account for surface distributions of the iogenic material and its chemical effects before real assessments can be made of sensible chemical materials otherwise arising from primordial formation and subsequent evolution of these moons. This is a fundamental problem of space weathering that must be addressed for all planetary bodies with thin atmospheres and direct surface exposure to their space plasma environments. Long-standing debates from Galileo Orbiter measurements about the origins of hydrate sulfates at Europa present examples of this problem, as to whether the sulfates arise from oceanic minerals or from iogenic sulfur chemistry. Any orbiter or landed mission to Europa for astrobiological investigations would further need to separate the potential chemical biosignatures of life or its precursors from the highly abundant background of iogenic material. Although no single ion carries a tag identifying it as of iogenic or other origin, the elemental abundance distributions of ions to be

2.7- to 4.1-micron spectrophotometry of icy satellites of Saturn and Jupiter

NASA Technical Reports Server (NTRS)

Lebofsky, L. A.; Feierberg, M. A.

1985-01-01

Spectrophotometry is presented in the 2.7-4.1 micrometer spectral region for icy satellites of Saturn (Tethys, Dione, Rhea, Iapetus and Hyperion) and Jupiter (Europa, Ganymede and Callisto). The 3.6-micrometer reflectance peak characteristic of fine-grained water ice is observed prominently on the satellites of Saturn, faintly on the leading side of Europa, and not at all on Ganymede, Callisto or the dark side of Iapetus. The spectral reflectances of these icy satellites may be affected by their equilibrium surface temperatures and magnetospheric effects.

Jupiter Eruptions

NASA Technical Reports Server (NTRS)

2008-01-01

[figure removed for brevity, see original site] Click on the image for high resolution image of Nature Cover

Detailed analysis of two continent-sized storms that erupted in Jupiter's atmosphere in March 2007 shows that Jupiter's internal heat plays a significant role in generating atmospheric disturbances. Understanding these outbreaks could be the key to unlock the mysteries buried in the deep Jovian atmosphere, say astronomers.

This visible-light image is from NASA's Hubble Space Telescope taken on May 11, 2007. It shows the turbulent pattern generated by the two plumes on the upper left part of Jupiter.

Understanding these phenomena is important for Earth's meteorology where storms are present everywhere and jet streams dominate the atmospheric circulation. Jupiter is a natural laboratory where atmospheric scientists study the nature and interplay of the intense jets and severe atmospheric phenomena.

According to the analysis, the bright plumes were storm systems triggered in Jupiter's deep water clouds that moved upward in the atmosphere vi gorously and injected a fresh mixture of ammonia ice and water about 20 miles (30 kilometers) above the visible clouds. The storms moved in the peak of a jet stream in Jupiter's atmosphere at 375 miles per hour (600 kilometers per hour). Models of the disturbance indicate that the jet stream extends deep in the buried atmosphere of Jupiter, more than 60 miles (approximately100 kilometers) below the cloud tops where most sunlight is absorbed.

Searches for Plumes and Ongoing Geologic Activity on Europa from Galileo and Other Spacecraft

NASA Astrophysics Data System (ADS)

Phillips, C. B.

2014-12-01

The recent discovery of an apparent plume erupting from Europa's surface using data from the Hubble Space Telescope (Roth et al. 2014) has prompted renewed interest in the possibility of recent or ongoing geologic activity on Europa. Here we summarize previous searches for plumes and changes on Europa's surface, and make recommendations for future efforts. During the period of time in which the Galileo spacecraft was in orbit in the Jupiter system, we made a number of comparisons with observations taken 20 years earlier by the Voyager spacecraft to look for surface changes (Phillips et al. 2000). We found no changes which were visible on Europa's surface. These comparisons, however, were necessarily limited by the low resolution of the Voyager images, which had a maximum resolution of about 2 km/pixel. We also used Galileo spacecraft data to search for plumes of material being ejected from Europa's surface. A 30-image observation was taken in 1999 to observe the limb and the dark sky just off the limb in a search for active plumes, but no plumes were observed (Phillips et al. 2000). However, Hoppa et al (1999) suggested that this image sequence occurred under unfavorable tidal stress conditions. Plume searches were also performed in eclipse images, but again no plumes were detected. More recently, we compared global-scale images of Europa taken in 2007 by the New Horizons spacecraft during its Jupiter flyby en route to Pluto (Bramson et al. 2011). After a careful search that included the iterative coregistration and ratioing techniques developed by Phillips et al. (2000), again, no changes were found on Europa's surface. If the recent Roth et al. (2014) suggestions of an active plume on Europa prove to be correct, we infer that one of two possibilities must be the case. Either 1) the plume is a recent event and was not active before the 2007 New Horizons flyby; or 2) the plume is intermittent and low-density, consisting primarily of gas and not dust, and therefore

Jupiter's Ring Halo

NASA Technical Reports Server (NTRS)

1997-01-01

A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (km) per picture element (pixel) along the rings; however, because the spacecraft was only about 0.5 degrees above the ring plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow peering back toward the Sun; the ring was approximately 2,300,000 kilometers (km) away. The arc on the far right of the image is produced by sunlight scattered by small particles comprising Jupiter's upper atmospheric haze. The ring also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age.

Jupiter's ring system is composed of three parts -- a flat main ring, a lenticular halo interior to the main ring, and the gossamer ring, which lies exterior to the main ring. The near and far arms of Jupiter's main ring extend horizontally across the mosaic, joining together at the ring's ansa, on the far left side of the figure. The near arm of the ring appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow.

A faint mist of particles can be seen above and below the main rings; this vertically extended, toroidal 'halo' is unusual in planetary rings, and is probably caused by electromagnetic forces which can push small grains out of the ring plane. Halo material is present across this entire image, implying that it reaches more than 27,000 km above the ring plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. In order to accentuate faint features in the image, different brightnesses are shown through color, with the brightest

Assessing the potential for passive radio sounding of Europa and Ganymede with RIME and REASON

NASA Astrophysics Data System (ADS)

Schroeder, Dustin M.; Romero-Wolf, Andrew; Carrer, Leonardo; Grima, Cyril; Campbell, Bruce A.; Kofman, Wlodek; Bruzzone, Lorenzo; Blankenship, Donald D.

2016-12-01

Recent work has raised the potential for Jupiter's decametric radiation to be used as a source for passive radio sounding of its icy moons. Two radar sounding instruments, the Radar for Icy Moon Exploration (RIME) and the Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) have been selected for ESA and NASA missions to Ganymede and Europa. Here, we revisit the projected performance of the passive sounding concept and assess the potential for its implementation as an additional mode for RIME and REASON. We find that the Signal to Noise Ratio (SNR) of passive sounding can approach or exceed that of active sounding in a noisy sub-Jovian environment, but that active sounding achieves a greater SNR in the presence of quiescent noise and outperforms passive sounding in terms of clutter. We also compare the performance of passive sounding at the 9 MHz HF center frequency of RIME and REASON to other frequencies within the Jovian decametric band. We conclude that the addition of a passive sounding mode on RIME or REASON stands to enhance their science return by enabling sub-Jovian HF sounding in the presence of decametric noise, but that there is not a compelling case for implementation at a different frequency.

Dark and Bright Ridges on Europa

NASA Technical Reports Server (NTRS)

1998-01-01

This high-resolution image of Jupiter's moon Europa, taken by NASA's Galileo spacecraft camera, shows dark, relatively smooth region at the lower right hand corner of the image which may be a place where warm ice has welled up from below. The region is approximately 30 square kilometers in area. An isolated bright hill stands within it. The image also shows two prominent ridges which have different characteristics; youngest ridge runs from left to top right and is about 5 kilometers in width (about 3.1 miles). The ridge has two bright, raised rims and a central valley. The rims of the ridge are rough in texture. The inner and outer walls show bright and dark debris streaming downslope, some of it forming broad fans. This ridge overlies and therefore must be younger than a second ridge running from top to bottom on the left side of the image. This dark 2 km wide ridge is relatively flat, and has smaller-scale ridges and troughs along its length.

North is to the top of the picture, and the sun illuminates the surface from the upper left. This image, centered at approximately 14 degrees south latitude and 194 degrees west longitude, covers an area approximately 15 kilometers by 20 kilometers (9 miles by 12 miles). The resolution is 26 meters (85 feet) per picture element. This image was taken on December 16, 1997 at a range of 1300 kilometers (800 miles) by Galileo's solid state imaging system.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

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

Atmospheric Motion in Jupiter Northern Hemisphere

NASA Image and Video Library

2000-09-25

True-color (left) and false-color (right) mosaics of Jupiter's northern hemisphere between 10 and 50 degrees latitude. Jupiter's atmospheric motions are controlled by alternating eastward and westward bands of air between Jupiter's equator and polar regions. The direction and speed of these bands influences the color and texture of the clouds seen in this mosaic. The high and thin clouds are represented by light blue, deep clouds are reddish, and high and thick clouds are white. A high haze overlying a clear, deep atmosphere is represented by dark purple. This image was taken by NASA's Galileo spacecraft on April 3, 1997 at a distance of 1.4 million kilometers (.86 million miles). http://photojournal.jpl.nasa.gov/catalog/PIA03000

The New Jupiter: Results from the Juno Mission

NASA Astrophysics Data System (ADS)

Bolton, Scott

2018-01-01

NASA's Juno mission to Jupiter launched in 2011 and arrived at Jupiter on July 4, 2016. Juno's scientific objectives include the study of Jupiter's interior, atmosphere and magnetosphere with the goal of understanding Jupiter's origin, formation and evolution. An extensive campaign of Earth based observations of Jupiter and the solar wind were orchestrated to complement Juno measurements during Juno's approach to Jupiter and during its orbital mission around Jupiter. This presentation provides an overview of results from the Juno measurements during the early phases of Juno's prime mission. Scientific results include Jupiter's interior structure, magnetic field, deep atmospheric dynamics and composition, and the first in-situ exploration of Jupiter's polar magnetosphere and aurorae.

Jupiter From Below (Enhanced Color)

NASA Image and Video Library

2017-02-08

This enhanced-color image of Jupiter's south pole and its swirling atmosphere was created by citizen scientist Roman Tkachenko using data from the JunoCam imager on NASA's Juno spacecraft. Juno acquired the image, looking directly at the Jovian south pole, on February 2, 2017, at 6:06 a.m. PST (9:06 a.m. EST) from an altitude of about 63,400 miles (102,100 kilometers) above Jupiter's cloud tops. Cyclones swirl around the south pole, and white oval storms can be seen near the limb -- the apparent edge of the planet. http://photojournal.jpl.nasa.gov/catalog/PIA21381

New Changes in Jupiter Great Red Spot

NASA Image and Video Library

2015-10-13

This image is one of two images from NASA Hubble Space Telescope comparing the movement of Jupiter clouds. The movement of Jupiter's clouds can be seen by comparing the first map to the second one in this animated pair of images. Zooming in on the Great Red Spot at blue (below, at left) and red (below, at right) wavelengths reveals a unique filamentary feature not previously seen. http://photojournal.jpl.nasa.gov/catalog/PIA19648

The ionosphere of Europa from Galileo radio occultations

NASA Technical Reports Server (NTRS)

Kliore, A. J.; Hinson, D. P.; Flasar, F. M.; Nagy, A. F.; Cravens, T. E.

1997-01-01

The Galileo spacecraft performed six radio occultation observations of Jupiter's Galilean satellite Europa during its tour of the jovian system. In five of the six instances, these occultations revealed the presence of a tenuous ionosphere on Europa, with an average maximum electron density of nearly 10(4) per cubic centimeter near the surface and a plasma scale height of about 240 +/- 40 kilometers from the surface to 300 kilometers and of 440 +/- 60 kilometers above 300 kilometers. Such an ionosphere could be produced by solar photoionization and jovian magnetospheric particle impact in an atmosphere having a surface density of about 10(8) electrons per cubic centimeter. If this atmosphere is composed primarily of O2, then the principal ion is O2+ and the neutral atmosphere temperature implied by the 240-kilometer scale height is about 600 kelvin. If it is composed of H2O, the principal ion is H3O+ and the neutral temperature is about 340 kelvin. In either case, these temperatures are much higher than those observed on Europa's surface, and an external heating source from the jovian magnetosphere is required.

The ionosphere of Europa from Galileo radio occultations.

PubMed

Kliore, A J; Hinson, D P; Flasar, F M; Nagy, A F; Cravens, T E

1997-07-18

The Galileo spacecraft performed six radio occultation observations of Jupiter's Galilean satellite Europa during its tour of the jovian system. In five of the six instances, these occultations revealed the presence of a tenuous ionosphere on Europa, with an average maximum electron density of nearly 10(4) per cubic centimeter near the surface and a plasma scale height of about 240 +/- 40 kilometers from the surface to 300 kilometers and of 440 +/- 60 kilometers above 300 kilometers. Such an ionosphere could be produced by solar photoionization and jovian magnetospheric particle impact in an atmosphere having a surface density of about 10(8) electrons per cubic centimeter. If this atmosphere is composed primarily of O2, then the principal ion is O2+ and the neutral atmosphere temperature implied by the 240-kilometer scale height is about 600 kelvin. If it is composed of H2O, the principal ion is H3O+ and the neutral temperature is about 340 kelvin. In either case, these temperatures are much higher than those observed on Europa's surface, and an external heating source from the jovian magnetosphere is required.

Exogenic and endogenic Europa minerals

NASA Astrophysics Data System (ADS)

Maynard-Casely, H. E.; Brand, H. E. A.; Wilson, S. A.

2016-12-01

The Galileo Near Infrared Mapping Spectrometer (NIMS) identified a significant `non-ice' component upon the surface of Jupiter's moon Europa. Current explanations invoke both endogenic and exogenic origins for this material. It has long been suggested that magnesium and sodium sulfate minerals could have leached from the rock below a putative ocean (endogenic) 1 and that sulfuric acid hydrate minerals could have been radiologically produced from ionised sulfur originally from Io's volcanoes (exogenic) 2. However, a more recent theory proposes that the `non-ice' component could be radiation damaged NaCl leached from Europa's speculative ocean 3. What if the minerals are actually from combination of both endogenic and exogenic sources? To investigate this possibility we have focused on discovering new minerals that might form in the combination of the latter two cases, that is a mixture of leached sulfates hydrates with radiologically produced sulfuric acid. To this end we have explored a number of solutions in the MgSO4-H2SO4-H2O and Na2SO4-H2SO4-H2O systems, between 80 and 280 K with synchrotron x-ray powder diffraction. We report a number of new materials formed in this these ternary systems. This suggests that it should be considered that the `non-ice' component of the Europa's surface could be a material derived from endogenic and exogenic components. 1 Kargel, J. S. Brine volcanism and the interior structures of asteroids and icy satellites. Icarus 94, 368-390 (1991). 2 Carlson, R. W., Anderson, M. S., Mehlman, R. & Johnson, R. E. Distribution of hydrate on Europa: Further evidence for sulfuric acid hydrate. Icarus 177, 461-471, doi:10.1016/j.icarus.2005.03.026 (2005). 3 Hand, K. P. & Carlson, R. W. Europa's surface color suggests an ocean rich with sodium chloride. Geophysical Research Letters, 2015GL063559, doi:10.1002/2015gl063559 (2015).

Europa's induced magnetic field: How much of the signal is from the ocean?

NASA Astrophysics Data System (ADS)

Crary, F. J.; Dols, V. J.; Jia, X.; Paty, C. S.; Hale, J. M.

2017-12-01

The existence of a sub-surface ocean within Europa was demonstrated by the Galileo spacecraft's measurements of an induced dipole magnetic field. This field, produced by the time variable background magnetic field from Jupiter, is a result of currents flowing within an electrically conductive layer inside Europa, believed to be a liquid ocean. Unfortunately, interpretation of the Galileo results is complicated by the interaction between Jupiter's magnetosphere and Europa and its ionosphere. This interaction also produces magnetic field perturbations which add uncertainty and systematic errors to the determination of the induced field.Here, we estimate the contribution of the plasma interaction to the observed magnetic dipole, and discuss the implications for the properties of Europa's subsurface ocean. The Galileo data have primarily been analyzed by fitting a dipole to the observed magnetic field, without correcting for plasma effects. The data were fit to a dipole magnetic field, and the resulting magnetic moment is the sum of the induced moment from the ocean and a contribution from the plasma interaction. To estimate this contribution, we analyze the results of numerical simulations using exactly the same approach which has been used to analyze the real data. Since we know what ocean dipole was inserted in the models' boundary conditions, we therefore calculate the contribution from the plasma interaction. We have previously used this approach to estimate the sensitivity of the results to upstream plasma conditions. However, there is no assurance that one particular model is correct. In this work, we apply this approach to several different types of simulations, shedding light on the uncertainties in the ocean-induced signature.

Chandra Probes High-Voltage Auroras on Jupiter

NASA Astrophysics Data System (ADS)

2005-03-01

Scientists have obtained new insight into the unique power source for many of Jupiter's auroras, the most spectacular and active auroras in the Solar System. Extended monitoring of the giant planet with NASA's Chandra X-ray Observatory detected the presence of highly charged particles crashing into the atmosphere above its poles. X-ray spectra measured by Chandra showed that the auroral activity was produced by ions of oxygen and other elements that were stripped of most of their electrons. This implies that these particles were accelerated to high energies in a multimillion-volt environment above the planet's poles. The presence of these energetic ions indicates that the cause of many of Jupiter's auroras is different from auroras produced on Earth or Saturn. Chandra X-ray Image of Jupiter Chandra X-ray Image of Jupiter "Spacecraft have not explored the region above the poles of Jupiter, so X-ray observations provide one of the few ways to probe that environment," said Ron Elsner of the NASA Marshall Space Flight Center in Huntsville, Alabama, and lead author on a recently published paper describing these results in the Journal for Geophysical Research. "These results will help scientists to understand the mechanism for the power output from Jupiter's auroras, which are a thousand times more powerful than those on Earth." Electric voltages of about 10 million volts, and currents of 10 million amps - a hundred times greater than the most powerful lightning bolts - are required to explain the X-ray observations. These voltages would also explain the radio emission from energetic electrons observed near Jupiter by the Ulysses spacecraft. Schematic of Jupiter's Auroral Activity Production Schematic of Jupiter's Auroral Activity Production On Earth, auroras are triggered by solar storms of energetic particles, which disturb Earth's magnetic field. Gusts of particles from the Sun can also produce auroras on Jupiter, but unlike Earth, Jupiter has another way of producing

Radiolytic Gas-Driven Cryovolcanism at Europa

NASA Astrophysics Data System (ADS)

Killen, R. M.; Cooper, J. F.; Sarantos, M.; Sittler, E. C., Jr.

2014-12-01

A large apparent plume of water vapor was detected at the south pole of Europa in December 2012 by the Hubble Space Telescope [Roth et al., 2014] when Europa was near maximum radial distance (apojove) in its orbit around Jupiter. The absence thus far of further detections both at apojove and elsewhere may indicate an episodic source. There was reportedly no evident brightening locally or globally of the Europa oxygen neutral atmosphere coincident with the plume water vapor detection. This could be consistent with an O2-driven cryovolcanism model in which bubbles of trapped gases in the ice crust are released from clathrates on thermal contact with rising oceanic water and expand to force upward fluid flows to the surface. It has long been suggested [Chyba, 2000; Cooper et al., 2001] that the Europa ocean could be oxygenated by radiolytic oxygen from surface irradiation, also implying that the overlying ice crust could be saturated in oxygen clathrates [Hand et al., 2006]. That the moon ocean could be a potentially habitable environment by oxygenation or other processes has been a major motivation for missions to Europa. The radiolytic gas source would be far greater at Europa as compared to much lesser source rates for a similar model at Enceladus [Cooper et al., 2009]. Detected plume emissions could arise from both the directly ejected vapor and from sputtering and/or sublimation of chemically-active plume frost in the polar cap region. Europa's surface gravity is much higher than that of Enceladus, so most of the plume vapor would return to the surface as frost. If sputtering or radiolysis were active contributors to polar cap emissions from the frost, then emissions could also maximize at 6.5-hour intervals as Europa passes through the densest part of the jovian magnetospheric plasma sheet as well as at 85-hour apojove intervals of the orbital period. For comparison to available polar cap plume and global atmospheric observations we present ballistic simulations

Jupiter Polar Winds Movie Blowup

NASA Technical Reports Server (NTRS)

2001-01-01

Persistent polar storms and zonal winds on Jupiter can be seen in this magnified quadrant from a movie projecting images from NASA's Cassini spacecraft as if the viewer were looking down at Jupiter's north pole and the planet were flattened.

The sequence covers 70 days, from October 1 to December 9, 2000. Cassini's narrow-angle camera captured the images of Jupiter's atmosphere in the near-infrared region of the spectrum.

Like the accompanying full-circle movie of polar winds, this zoomed-inversion shows that the polar region has coherent flows, despite its chaotic, mottled appearance. There are thousands of spots, each an active storm similar in size to the largest storms on Earth. The spots occasionally change latitude or merge with each other, but usually they last for the entire 70 days. Until now, the lifetime of those storms was unknown.

The mystery of Jupiter's weather is why the storms last so long. Storms on Earth last for a week before they break up and are replaced by other storms. This movie heightens the mystery because it shows long-lived storms at the highest latitudes, where the weather patterns are more disorganized than at low latitudes.

Cassini collected images of Jupiter for months before and after it passed the planet on December 30, 2000. Six images or more of the planet in each of several spectral filters were taken at evenly spaced intervals over the course of Jupiter's 10-hour rotation period. The entire sequence was repeated generally every other Jupiter rotation, yielding views of every sector of the planet at least once every 20 hours.

The images used for the movie shown here were taken every 20 hours through a filter centered at a wavelength of 756 nanometers, where there are almost no absorptions in the planet's atmosphere. Images from each rotation were assembled first into a cylindrical map. The 84 resulting cylindrical maps, spanning 70 Earth days or 168 Jupiter rotations, were transformed to polar stereographic

Cold Hole Over Jupiter's Pole

NASA Technical Reports Server (NTRS)

2002-01-01

Observations with two NASA telescopes show that Jupiter has an arctic polar vortex similar to a vortex over Earth's Antarctica that enables depletion of Earth's stratospheric ozone.

These composite images of Jupiter's north polar region from the Hubble Space Telescope (right) and the Infrared Telescope Facility (left) show a quasi-hexagonal shape that extends vertically from the stratosphere down into the top of the troposphere. A sharp temperature drop, compared to surrounding air masses, creates an eastward wind that tends to keep the polar atmosphere, including the stratospheric haze, isolated from the rest of the atmosphere.

The linear striations in the composite projections are artifacts of the image processing. The area closest to the pole has been omitted because it was too close to the edge of the planet in the original images to represent the planet reliably.

The composite on the right combines images from the Wide Field and Planetary Camera 2 of the Hubble Space Telescope taken at a wavelength of 890 nanometers, which shows stratospheric haze particles.

The sharp boundary and wave-like structure of the haze layer suggest a polar vortex and a similarity to Earth's stratospheric polar clouds. Images of Jupiter's thermal radiation clinch that identification. The composite on the left, for example, is made from images taken with Jet Propulsion Laboratory's Mid-Infrared Large-Well Imager at NASA's Infrared Telescope Facility at a wavelength of 17 microns. It shows polar air mass that is 5 to 6 degrees Celsius (9 to 10 degrees Fahrenheit) colder than its surroundings, with the same border as the stratospheric haze. Similar observations at other infrared wavelengths show the cold air mass extends at least as high as the middle stratosphere down to the top of the troposphere.

These images were taken Aug. 11 through Aug. 13, 1999, near a time when Jupiter's north pole was most visible from Earth. Other Infrared Telescope Facility images at

95 Minutes Over Jupiter

NASA Image and Video Library

2017-09-28

This sequence of color-enhanced images shows how quickly the viewing geometry changes for NASA's Juno spacecraft as it swoops by Jupiter. The images were obtained by JunoCam. Once every 53 days, Juno swings close to Jupiter, speeding over its clouds. In just two hours, the spacecraft travels from a perch over Jupiter's north pole through its closest approach (perijove), then passes over the south pole on its way back out. This sequence shows 11 color-enhanced images from Perijove 8 (Sept. 1, 2017) with the south pole on the left (11th image in the sequence) and the north pole on the right (first image in the sequence). The first image on the right shows a half-lit globe of Jupiter, with the north pole approximately at the upper center of the image close to the terminator -- the dividing line between night and day. As the spacecraft gets closer to Jupiter, the horizon moves in and the range of visible latitudes shrinks. The second and third images in this sequence show the north polar region rotating away from the spacecraft's field of view while the first of Jupiter's lighter-colored bands comes into view. The fourth through the eighth images display a blue-colored vortex in the mid-southern latitudes near Points of Interest "Collision of Colours," "Sharp Edge," "Caltech, by Halka," and "Structure01." The Points of Interest are locations in Jupiter's atmosphere that were identified and named by members of the general public. Additionally, a darker, dynamic band can be seen just south of the vortex. In the ninth and tenth images, the south polar region rotates into view. The final image on the left displays Jupiter's south pole in the center. From the start of this sequence of images to the end, roughly 1 hour and 35 minutes elapsed. https://photojournal.jpl.nasa.gov/catalog/PIA21967

EUROPA Multiple-Flyby Trajectory Design

NASA Technical Reports Server (NTRS)

Buffington, Brent; Campagnola, Stefano; Petropoulos, Anastassios

2012-01-01

As reinforced by the 2011 NRC Decadal Survey, Europa remains one of the most scientifically intriguing targets in planetary science due to its potential suitability for life. However, based on JEO cost estimates and current budgetary constraints, the Decadal Survey recommended-and later directed by NASA Headquarters-a more affordable pathway to Europa exploration be derived. In response, a flyby-only proof-of-concept trajectory has been developed to investigate Europa. The trajectory, enabled by employing a novel combination of new mission design techniques, successfully fulfills a set of Science Definition Team derived scientific objectives carried out by a notional payload including ice penetrating radar, topographic imaging, and short wavelength infrared observations, and ion neutral mass spectrometry in-situ measurements. The current baseline trajectory, referred to as 11-F5, consists of 34 Europa and 9 Ganymede flybys executed over the course of 2.4 years, reached a maximum inclination of 15 degrees, has a deterministic delta v of 157 m/s (post-PJR), and has a total ionizing dose of 2.06 Mrad (Si behind 100 mil Al, spherical shell). The 11-F5 trajectory and more generally speaking, flyby-only trajectories-exhibit a number of potential advantages over an Europa orbiter mission.

Automated Estimation of the Orbital Parameters of Jupiter's Moons

NASA Astrophysics Data System (ADS)

Western, Emma; Ruch, Gerald T.

2016-01-01

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

Thunderheads on Jupiter

NASA Image and Video Library

1997-09-08

Scientists have spotted what appear to be thunderheads on Jupiter bright white cumulus clouds similar to those that bring thunderstorms on Earth - at the outer edges of Jupiter's Great Red Spot. Images from NASA's Galileo spacecraft now in orbit around Jupiter are providing new evidence that thunderstorms may be an important source of energy for Jupiter's winds that blow at more than 500 kilometers per hour (about 300 miles per hour). The photos were taken by Galileo's solid state imager camera on June 26, 1996 at a range of about 1.4 million kilometers (about 860,000 miles). The image at top is a mosaic of multiple images taken through near-infrared filters. False coloring in the image reveals cloud-top heights. High, thick clouds are white and high, thin clouds are pink. Low-altitude clouds are blue. The two black-and-white images at bottom are enlargements of the boxed area; the one on the right was taken 70 minutes after the image on the left. The arrows show where clouds have formed or dissipated in the short time between the images. The smallest clouds are tens of kilometers across. On Earth, moist convection in thunderstorms is a pathway through which solar energy, deposited at the surface, is transported and delivered to the atmosphere. Scientists at the California Institute of Technology analyzing data from Galileo believe that water, the most likely candidate for what composes these clouds on Jupiter, may be more abundant at the site seen here than at the Galileo Probe entry site, which was found to be unexpectedly dry. http://photojournal.jpl.nasa.gov/catalog/PIA00506

Europa's Habitability follows from Classical Dynamical Astronomy

NASA Astrophysics Data System (ADS)

Greenberg, R.

2001-11-01

Celestial mechanics is responsible for Jupiter's satellite Europa being a possible site for life in the solar system. The Laplace orbital resonance drives a substantial eccentricity. The mutually dependent relationship between orbital and rotational evolution and tidal processes in turn controls Europa's heating and stress. Heat is likely adequate to maintain a liquid water ocean, and to keep the surface ice thin. Tidal stress can explain characteristic and ubiquitous crack patterns (global and cycloidal), as well as drive observed shear displacement features. The characteristic ridge sets that cover tectonic terrain are likely built by tidal pumping of oceanic fluid and slush through cracks to the surface on a daily basis. Nearly half the surface is chaotic terrain, with morphology and other characteristics indicative of melt-through from below. Formation of both chaotic and tectonic terrains has continually resurfaced the satellite, while connecting the ocean to the surface and providing a variety of evolving environmental niches. As a result of tides, liquid water would daily bathe crustal cracks and surfaces with heat, transporting and mixing substances vertically. Thus a variety of habitable environments likely exist in the crust. Moreover, exposure of the ocean to the surface in the ways described here satisfies a necessary condition for life in the ocean as well, by providing access to oxidants which are available near the surface. These processes were recent, and thus most likely continue today. Longer term changes in environmental conditions in the crust, such as deactivation of individual cracks after thousands of years (due to non-synchronous rotation) and later crustal thawing (releasing any trapped organisms), provided drivers for adaptation, as well as opportunity for evolution. This work is supported by the NASA Planetary Geology and Geophysics Program and the NSF Life in Extreme Environments Program.

Understanding the Cryosphere of Europa Using Imaging Spectroscopy

NASA Astrophysics Data System (ADS)

Blaney, D. L.; Green, R. O.; Hibbitts, C.; Clark, R. N.; Dalton, J. B.; Davies, A. G.; Langevin, Y.; Hedman, M.; Lunine, J. I.; McCord, T. B.; Murchie, S. L.; Paranicas, C.; Seelos, F. P.; Soderblom, J. M.; Diniega, S.

2017-12-01

Europa's surface expresses a complex interplay of geologic processes driven by the ocean beneath the cryosphere that are subsequently modified by the Jovian environment once exposed on the surface. Several recent Earth-based observations of Europa's tenuous atmosphere suggest that there may in fact be active plumes [1,2,3]. However, the frequency and the duration of activity at any specific location cannot be precisely determined by these observations, but could be with spacecraft observations. For instance, recently active areas on Europa from plumes or other processes may result in distinctive spectral signatures on the surface. Possible spectral signatures that may indicate recent activity include: differences in ice grain size or ice crystallinity; the lack of radiolytic signatures (e.g. a deficit in species due to implantation, radiation darkening of salts, degradation of organic compounds); and thermal anomalies. The Mapping Imaging Spectrometer for Europa (MISE) on NASA's Europa Clipper Mission will be able to map these species thus enabling the identification of these deposits and other young and/or least processed areas. These signatures may also enable a relative geochronology for Europa to be developed. For example, recent work by Proctor et al [4] finds that bands of different stratigraphic ages have different spectral features potentially due to radiation effects on the deposits. We will explore borrowing analyses techniques from earth observing missions of the Arctic. On Earth, data from the Airborne Visible / Infrared Imaging Spectrometer Next Generation (AVRIS-NG) (https://avirisng.jpl.nasa.gov/aviris-ng.html) is being used to explore Earth's cryosphere. AVRIS-NG data collected from the Greenland ice sheet and high latitude sea ice is being used to map of key ice properties such as grain size and contaminants. These data and processing approaches will be used to explore and validate imaging spectroscopy approaches which MISE might use on Europa.

Jupiter's Great Red Spot (Enhanced Color)

NASA Image and Video Library

2017-07-12

This enhanced-color image of Jupiter's Great Red Spot was created by citizen scientist Jason Major using data from the JunoCam imager on NASA's Juno spacecraft. The image was taken on July 10, 2017 at 07:10 p.m. PDT (10:10 p.m. EDT), as the Juno spacecraft performed its 7th close flyby of Jupiter. At the time the image was taken, the spacecraft was about 8,648 miles (13,917 kilometers) from the tops of the clouds of the planet. https://photojournal.jpl.nasa.gov/catalog/PIA21772

Jupiter Pearl and Swirling Cloud Tops

NASA Image and Video Library

2017-01-19

This amateur-processed image was taken on Dec. 11, 2016, at 9:27 a.m. PST (12:27 p.m. EST), as NASA's Juno spacecraft performed its third close flyby of Jupiter. At the time the image was taken, the spacecraft was about 15,200 miles (24,400 kilometers) from the gas giant planet. The citizen scientist (Eric Jorgensen) cropped the JunoCam image and enhanced the color to draw attention to Jupiter's swirling clouds southeast of the "pearl." The "pearl" is one of eight massive rotating storms at 40 degrees south latitude on Jupiter, known colloquially as the "string of pearls." The processing of this image highlights the turbulence of the clouds in the south temperate belt of the planet. http://photojournal.jpl.nasa.gov/catalog/PIA21377

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

PROBING FOR EVIDENCE OF PLUMES ON EUROPA WITH HST /STIS

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

Sparks, W. B.; Bergeron, E.; Cracraft, M.

2016-10-01

Roth et al. (2014a) reported evidence for plumes of water venting from a southern high latitude region on Europa: spectroscopic detection of off-limb line emission from the dissociation products of water. Here, we present Hubble Space Telescope direct images of Europa in the far-ultraviolet (FUV) as it transited the smooth face of Jupiter to measure absorption from gas or aerosols beyond the Europa limb. Out of 10 observations, we found 3 in which plume activity could be implicated. Two observations showed statistically significant features at latitudes similar to Roth et al., and the third at a more equatorial location. Wemore » consider potential systematic effects that might influence the statistical analysis and create artifacts, and are unable to find any that can definitively explain the features, although there are reasons to be cautious. If the apparent absorption features are real, the magnitude of implied outgassing is similar to that of the Roth et al. feature; however, the apparent activity appears more frequently in our data.« less

Ocean-driven heating of Europa's icy shell at low latitudes

NASA Astrophysics Data System (ADS)

Soderlund, K. M.; Schmidt, B. E.; Wicht, J.; Blankenship, D. D.

2014-01-01

The ice shell of Jupiter's moon Europa is marked by regions of disrupted ice known as chaos terrains that cover up to 40% of the satellite's surface, most commonly occurring within 40° of the equator. Concurrence with salt deposits implies a coupling between the geologically active ice shell and the underlying liquid water ocean at lower latitudes. Europa's ocean dynamics have been assumed to adopt a two-dimensional pattern, which channels the moon's internal heat to higher latitudes. Here we present a numerical model of thermal convection in a thin, rotating spherical shell where small-scale convection instead adopts a three-dimensional structure and is more vigorous at lower latitudes. Global-scale currents are organized into three zonal jets and two equatorial Hadley-like circulation cells. We find that these convective motions transmit Europa's internal heat towards the surface most effectively in equatorial regions, where they can directly influence the thermo-compositional state and structure of the ice shell. We suggest that such heterogeneous heating promotes the formation of chaos features through increased melting of the ice shell and subsequent deposition of marine ice at low latitudes. We conclude that Europa's ocean dynamics can modulate the exchange of heat and materials between the surface and interior and explain the observed distribution of chaos terrains.

Jupiter's Southern Lights

NASA Image and Video Library

2017-05-25

The complexity and richness of Jupiter's "southern lights" (also known as auroras) are on display in this animation of false-color maps from NASA's Juno spacecraft. Auroras result when energetic electrons from the magnetosphere crash into the molecular hydrogen in the Jovian upper atmosphere. The data for this animation were obtained by Juno's Ultraviolet Spectrograph. The images are centered on the south pole and extend to latitudes of 50 degrees south. Each frame of the animation includes data from 30 consecutive Juno spins (about 15 minutes), just after the spacecraft's fifth close approach to Jupiter on February 2, 2017. The eight frames of the animation cover the period from 13:40 to 15:40 UTC at Juno. During that time, the spacecraft was receding from 35,000 miles to 153,900 miles (56,300 kilometers to 247,600 kilometers) above the aurora; this large change in distance accounts for the increasing fuzziness of the features. Jupiter's prime meridian is toward the bottom, and longitudes increase counterclockwise from there. The sun was located near the bottom at the start of the animation, but was off to the right by the end of the two-hour period. The red coloring of some of the features indicates that those emissions came from deeper in Jupiter's atmosphere; green and white indicate emissions from higher up in the atmosphere. Animations are available at https://photojournal.jpl.nasa.gov/catalog/PIA21643

Jupiter Down Under

NASA Image and Video Library

2016-09-02

This image from NASA's Juno spacecraft provides a never-before-seen perspective on Jupiter's south pole. The JunoCam instrument acquired the view on August 27, 2016, when the spacecraft was about 58,700 miles (94,500 kilometers) above the polar region. At this point, the spacecraft was about an hour past its closest approach, and fine detail in the south polar region is clearly resolved. Unlike the equatorial region's familiar structure of belts and zones, the poles are mottled by clockwise and counterclockwise rotating storms of various sizes, similar to giant versions of terrestrial hurricanes. The south pole has never been seen from this viewpoint, although the Cassini spacecraft was able to observe most of the polar region at highly oblique angles as it flew past Jupiter on its way to Saturn in 2000. http://photojournal.jpl.nasa.gov/catalog/PIA21032

Active formation of 'chaos terrain' over shallow subsurface water on Europa.

PubMed

Schmidt, B E; Blankenship, D D; Patterson, G W; Schenk, P M

2011-11-16

Europa, the innermost icy satellite of Jupiter, has a tortured young surface and sustains a liquid water ocean below an ice shell of highly debated thickness. Quasi-circular areas of ice disruption called chaos terrains are unique to Europa, and both their formation and the ice-shell thickness depend on Europa's thermal state. No model so far has been able to explain why features such as Conamara Chaos stand above surrounding terrain and contain matrix domes. Melt-through of a thin (few-kilometre) shell is thermodynamically improbable and cannot raise the ice. The buoyancy of material rising as either plumes of warm, pure ice called diapirs or convective cells in a thick (>10 kilometres) shell is insufficient to produce the observed chaos heights, and no single plume can create matrix domes. Here we report an analysis of archival data from Europa, guided by processes observed within Earth's subglacial volcanoes and ice shelves. The data suggest that chaos terrains form above liquid water lenses perched within the ice shell as shallow as 3 kilometres. Our results suggest that ice-water interactions and freeze-out give rise to the diverse morphologies and topography of chaos terrains. The sunken topography of Thera Macula indicates that Europa is actively resurfacing over a lens comparable in volume to the Great Lakes in North America. ©2011 Macmillan Publishers Limited. All rights reserved

Active formation of `chaos terrain' over shallow subsurface water on Europa

NASA Astrophysics Data System (ADS)

Schmidt, B. E.; Blankenship, D. D.; Patterson, G. W.; Schenk, P. M.

2011-11-01

Europa, the innermost icy satellite of Jupiter, has a tortured young surface and sustains a liquid water ocean below an ice shell of highly debated thickness. Quasi-circular areas of ice disruption called chaos terrains are unique to Europa, and both their formation and the ice-shell thickness depend on Europa's thermal state. No model so far has been able to explain why features such as Conamara Chaos stand above surrounding terrain and contain matrix domes. Melt-through of a thin (few-kilometre) shell is thermodynamically improbable and cannot raise the ice. The buoyancy of material rising as either plumes of warm, pure ice called diapirs or convective cells in a thick (>10 kilometres) shell is insufficient to produce the observed chaos heights, and no single plume can create matrix domes. Here we report an analysis of archival data from Europa, guided by processes observed within Earth's subglacial volcanoes and ice shelves. The data suggest that chaos terrains form above liquid water lenses perched within the ice shell as shallow as 3kilometres. Our results suggest that ice-water interactions and freeze-out give rise to the diverse morphologies and topography of chaos terrains. The sunken topography of Thera Macula indicates that Europa is actively resurfacing over a lens comparable in volume to the Great Lakes in North America.

Stormy Day at Jupiter

NASA Image and Video Library

2017-05-25

Small bright clouds dot Jupiter's entire south tropical zone in this image acquired by JunoCam on NASA's Juno spacecraft on May 19, 2017, at an altitude of 7,990 miles (12,858 kilometers). Although the bright clouds appear tiny in this vast Jovian cloudscape, they actually are cloud towers roughly 30 miles (50 kilometers) wide and 30 miles (50 kilometers) high that cast shadows on the clouds below. On Jupiter, clouds this high are almost certainly composed of water and/or ammonia ice, and they may be sources of lightning. This is the first time so many cloud towers have been visible, possibly because the late-afternoon lighting is particularly good at this geometry. https://photojournal.jpl.nasa.gov/catalog/PIA21647

Jupiter

NASA Astrophysics Data System (ADS)

Bagenal, Fran; Dowling, Timothy E.; McKinnon, William B.

2007-03-01

Preface; 1. Introduction F. Bagenal, T. E. Dowling and W. B. McKinnon; 2. The origin of Jupiter J. I. Lunine, A. Corandini, D. Gautier, T. C. Owen and G. Wuchterl; 3. The interior of Jupiter T. Guillot, D. J. Stevenson, W. B. Hubbard and D. Saumon; 4. The composition of the atmosphere of Jupiter F. W. Taylor, S. K. Atreya, Th. Encrenaz, D. M. Hunten, P. G. J. Irwin and T. C. Owen; 5. Jovian clouds and haze R. A. West, K. H. Baines, A. J. Friedson, D. Banfield, B. Ragent and F. W. Taylor; 6. Dynamics of Jupiter's atmosphere A. P. Ingersoll, T. E. Dowling, P. J. Gierasch, G. S. Orton, P. L. Read, A. Sánchez-Lavega, A. P. Showman, A. A. Simon-Miller and A. R. Vasavada; 7. The stratosphere of Jupiter J. I. Moses, T. Fouchet, R. V. Yelle, A. J. Friedson, G. S. Orton, B. Bézard, P. Drossart, G. R. Gladstone, T. Kostiuk and T. A. Livengood; 8. Lessons from Shoemaker-Levy 9 about Jupiter and planetary impacts J. Harrington, I. de Pater, S. H. Brecht, D. Deming, V. Meadows, K. Zahnle and P. D. Nicholson; 9. Jupiter's thermosphere and ionosphere R. V. Yelle and S. Miller; 10. Jovian dust: streams, clouds and rings H. Krüger, M. Horányi, A. V. Krivov and A. L. Graps; 11. Jupiter's ring-moon system J. A. Burns, D. P. Simonelli, M. R. Showalter, D. P. Hamilton, C. C. Porco, H. Throop and L. W. Esposito; 12. Jupiter's outer satellites and trojans D. C. Jewitt, S. Sheppard and C. Porco; 13. Interior composition, structure and dynamics of the Galilean satellites G. Schubert, J. D. Anderson, T. Spohn and W. B. McKinnon; 14. The lithosphere and surface of Io A. S. McEwen, L. P. Keszthelyi, R. Lopes, P. M. Schenk and J. R. Spencer; 15. Geology of Europa R. Greeley, C. F. Chyba, J. W. Head III, T. B. McCord, W. B. McKinnon, R. T. Pappalardo and P. Figueredo; 16. Geology of Ganymede R. T. Pappalardo, G. C. Collins, J. W. Head III, P. Helfenstein, T. B. McCord, J. M. Moore, L. M. Procktor, P. M. Shenk and J. R. Spencer; 17. Callisto J. M. Moore, C. R. Chapman. E. B. Bierhaus, R

Jupiter Polar Haze in False Color

NASA Image and Video Library

2017-02-01

This false color view of Jupiter's polar haze was created by citizen scientist Gerald Eichstädt using data from the JunoCam instrument on NASA's Juno spacecraft. The image was taken on Dec. 11, 2016 at 2:30 p.m. PST (5:30 p.m. EST), when the spacecraft was 285,000 miles (459,000 kilometers) from Jupiter on the outbound leg of its third close flyby. This image is composited from four images taken through different filters: red, green, blue and methane. When the near-infrared methane image is processed with the others, the result is a false color product that highlights high clouds and high altitude hazes. The Great Red Spot and Oval BA (just below the Great Red Spot) are high in Jupiter's atmosphere, thus bright in this picture. The high-altitude haze layer over the south pole partially obscures our view of the storms below. By combining the methane data with the visible light images, we can learn about the vertical structure of Jupiter's atmosphere. http://photojournal.jpl.nasa.gov/catalog/PIA21379

Using Methane Absorption to Probe Jupiter's Atmosphere

NASA Technical Reports Server (NTRS)

1997-01-01

Mosaics of a belt-zone boundary near Jupiter's equator in near-infrared light moderately absorbed by atmospheric methane (top panel), and strongly absorbed by atmospheric methane (bottom panel). The four images that make up each of these mosaics were taken within a few minutes of each other. Methane in Jupiter's atmosphere absorbs light at specific wavelengths called absorption bands. By detecting light close and far from these absorption bands, Galileo can probe to different depths in Jupiter's atmosphere. Sunlight near 732 nanometers (top panel) is moderately absorbed by methane. Some of the light reflected from clouds deep in Jupiter's troposphere is absorbed, enhancing the higher features. Sunlight at 886 nanometers (bottom panel) is strongly absorbed by methane. Most of the light reflected from the deeper clouds is absorbed, making these clouds invisible. Features in the diffuse cloud layer higher in Jupiter's atmosphere are greatly enhanced.

North is at the top. The mosaic covers latitudes -13 to +3 degrees and is centered at longitude 282 degrees West. The smallest resolved features are tens of kilometers in size. These images were taken on November 5th, 1996, at a range of 1.2 million kilometers by the Solid State Imaging system aboard NASA's Galileo spacecraft.

The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

Slices of Jupiter's Great Red Spot

NASA Image and Video Library

2017-12-11

This figure shows data from the six channels of the microwave radiometer (MWR) instrument onboard NASA's Juno spacecraft. The data were collected in the mission's sixth science orbit (referred to as "perijove 7"), during which the spacecraft passed over Jupiter's Great Red Spot. The top layer in the figure is a visible light image from the mission's JunoCam instrument, provided for context. The MWR instrument enables Juno to see deeper into Jupiter than any previous spacecraft or Earth-based observations. Each MWR channel peers progressively deeper below the visible cloud tops. Channel 1 is sensitive to longer microwave wavelengths; each of the other channels is sensitive to progressively shorter wavelengths. The large-scale structure of the Great Red Spot is visible in the data as deep into Jupiter as MWR can observe. https://photojournal.jpl.nasa.gov/catalog/PIA22177

Winds Near Jupiter's Belt-Zone Boundary

NASA Technical Reports Server (NTRS)

1997-01-01

Time Sequence of a belt-zone boundary near Jupiter's equator. These mosaics show Jupiter's appearance at 757 nanometers (near-infrared) and were taken nine hours apart. Images at 757 nanometers show features of Jupiter's primary visible cloud deck.

Jupiter's atmospheric circulation is dominated by alternating jets of east/west (zonal) winds. The bands have different widths and wind speeds but have remained constant as long as telescopes and spacecraft have measured them. A strong eastward jet is made visible as it stretches the clouds just below the center of this mosaic. The maximum wind speed of this jet is 128 meters per second (286 miles per hour). Features on this jet move about one quarter of the width of the mosaic. All the features visible in these mosaics are moving eastward (right).

North is at the top. The mosaic covers latitudes -13 to +3 degrees and is centered at longitude 282 degrees West. The smallest resolved features are tens of kilometers in size. These images were taken on November 5th, 1996, at a range of 1.2 million kilometers by the Solid State Imaging system aboard NASA's Galileo spacecraft.

The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

Integration of CubeSat Systems with Europa Surface Exploration Missions

NASA Astrophysics Data System (ADS)

Erdoǧan, Enes; Inalhan, Gokhan; Kemal Üre, Nazım

2016-07-01

Recent studies show that there is a high probability that a liquid ocean exists under thick icy surface of Jupiter's Moon Europa. The findings also show that Europa has features that are similar to Earth, such as geological activities. As a result of these studies, Europa has promising environment of being habitable and currently there are many missions in both planning and execution level that target Europa. However, these missions usually involve extremely high budgets over extended periods of time. The objective of this talk is to argue that the mission costs can be reduced significantly by integrating CubeSat systems within Europa exploration missions. In particular, we introduce an integrated CubeSat-micro probe system, which can be used for measuring the size and depth of the hypothetical liquid ocean under the icy surface of Europa. The systems consist of an entry module that houses a CubeSat combined with driller measurement probes. Driller measurement probes deploy before the system hits the surface and penetrate the surface layers of Europa. Moreover, a micro laser probe could be used to examine the layers. This process enables investigation of the properties of the icy layer and the environment beneath the surface. Through examination of different scenarios and cost analysis of the components, we show that the proposed CubeSat systems has a significant potential to reduce the cost of the overall mission. Both subsystem requirements and launch prices of CubeSats are dramatically cheaper than currently used satellites. In addition, multiple CubeSats may be used to dominate wider area in space and they are expandable in face of potential failures. In this talk we discuss both the mission design and cost reduction aspects.

EUROPA2: Plan Database Services for Planning and Scheduling Applications

NASA Technical Reports Server (NTRS)

Bedrax-Weiss, Tania; Frank, Jeremy; Jonsson, Ari; McGann, Conor

2004-01-01

NASA missions require solving a wide variety of planning and scheduling problems with temporal constraints; simple resources such as robotic arms, communications antennae and cameras; complex replenishable resources such as memory, power and fuel; and complex constraints on geometry, heat and lighting angles. Planners and schedulers that solve these problems are used in ground tools as well as onboard systems. The diversity of planning problems and applications of planners and schedulers precludes a one-size fits all solution. However, many of the underlying technologies are common across planning domains and applications. We describe CAPR, a formalism for planning that is general enough to cover a wide variety of planning and scheduling domains of interest to NASA. We then describe EUROPA(sub 2), a software framework implementing CAPR. EUROPA(sub 2) provides efficient, customizable Plan Database Services that enable the integration of CAPR into a wide variety of applications. We describe the design of EUROPA(sub 2) from the perspective of both modeling, customization and application integration to different classes of NASA missions.

Project GALILEO: Farewell to the Major Moons of Jupiter

NASA Astrophysics Data System (ADS)

Theilig, E.

2002-01-01

After a six year odyssey, Galileo has completed its survey of the large moons of Jupiter. In the four years since the end of the primary mission, Galileo provided new insights into the fundamental questions concerning Jupiter and its moons and magnetosphere. Longevity, changing orbital geometry, and multiple flybys afforded the opportunity to distinguish intrinsic versus induced magnetic fields on the Galilean moons, to characterize the dusk side of the magnetosphere, to acquire high resolution observations supporting the possibility of subsurface water within Europa, Ganymede, and Callisto, and to monitor the highly dynamic volcanic activity of Io. In January 2002, a final gravity assist placed the spacecraft on a two-orbit trajectory culminating in a Jupiter impact in September 2003. With the successful completion of the Io encounters, plans are being made for the final encounter of the mission. In November 2002, the spacecraft will fly one Jupiter radius above the planet's cloud-tops, sampling the inner magnetosphere and the gossamer rings. The trajectory will take Galileo close enough to Amalthea, (a small inner moon) to obtain the first gravity data for this body. Because a radiation dose of 73 krads is expected on this encounter, which will bring the total radiation dose to greater than four times the spacecraft design limits, the command sequence has to account for the possibility of subsystem failure and the loss of spacecraft control after this perijove passage. One of the primary objectives this year has been to place the spacecraft on a trajectory to impact Jupiter on orbit 35. Galileo's discovery of water beneath the frozen surface of Europa raised concerns about forward contamination by inadvertently impacting that moon and resulted in an end of mission requirement to dispose of the spacecraft. A risk assessment of the final two Io encounters was performed to manage the project's ability to meet this requirement. Radiation affected the extended mission

Occurrence and Detectability of Thermal Anomalies on Europa

NASA Astrophysics Data System (ADS)

Hayne, Paul O.; Christensen, Philip R.; Spencer, John R.; Abramov, Oleg; Howett, Carly; Mellon, Michael; Nimmo, Francis; Piqueux, Sylvain; Rathbun, Julie A.

2017-10-01

Endogenic activity is likely on Europa, given its young surface age of and ongoing tidal heating by Jupiter. Temperature is a fundamental signature of activity, as witnessed on Enceladus, where plumes emanate from vents with strongly elevated temperatures. Recent observations suggest the presence of similar water plumes at Europa. Even if plumes are uncommon, resurfacing may produce elevated surface temperatures, perhaps due to near-surface liquid water. Detecting endogenic activity on Europa is one of the primary mission objectives of NASA’s planned Europa Clipper flyby mission.Here, we use a probabilistic model to assess the likelihood of detectable thermal anomalies on the surface of Europa. The Europa Thermal Emission Imaging System (E-THEMIS) investigation is designed to characterize Europa’s thermal behavior and identify any thermal anomalies due to recent or ongoing activity. We define “detectability” on the basis of expected E-THEMIS measurements, which include multi-spectral infrared emission, both day and night.Thermal anomalies on Europa may take a variety of forms, depending on the resurfacing style, frequency, and duration of events: 1) subsurface melting due to hot spots, 2) shear heating on faults, and 3) eruptions of liquid water or warm ice on the surface. We use numerical and analytical models to estimate temperatures for these features. Once activity ceases, lifetimes of thermal anomalies are estimated to be 100 - 1000 yr. On average, Europa’s 10 - 100 Myr surface age implies a resurfacing rate of ~3 - 30 km2/yr. The typical size of resurfacing features determines their frequency of occurrence. For example, if ~100 km2 chaos features dominate recent resurfacing, we expect one event every few years to decades. Smaller features, such as double-ridges, may be active much more frequently. We model each feature type as a statistically independent event, with probabilities weighted by their observed coverage of Europa’s surface. Our results

Europa Sample Return Mission Utilizing High Specific Impulse Propulsion Refueled with Indigenous Resources

NASA Astrophysics Data System (ADS)

Paniagua, J.; Powell, J. R.; Maise, G.

2002-01-01

. Europa, in the Jovian system, is a high priority target for an outer Solar System exploration mission. More than a decade ago the Voyager spacecraft revealed Europa as a world swathed in ice and geologically young. NASA's Galileo spacecraft passed approximately 500 miles above the surface and provided detailed images of Europa's terrain marked by a dynamic topology that appeared to be remnants of ice volcanoes or geysers. The surface temperature averages a chilly -200° C. The pictures appear to show a relatively young surface of ice, possibly only 1 km thick in some places. Internal heating of Europa from Jupiter's tidal pull could form an ocean of liquid water beneath the surface. More recently, Ganymede and Callisto are believed to be ocean-bearing Jovian moons based on magnetometer measurements from the Galileo spacecraft. If liquid water exists, life may also. NASA plans to send an orbiting spacecraft to Europa to measure the thickness of the ice and to detect if an underlying liquid ocean exists. This mission would precede the proposed Europa Sample Return mission, which includes dispatching an autonomous submarine-like vehicle that could melt through the ice and explore the undersea realm. Because of the large energy requirements typical of these ambitious solar system science missions, use of chemical rockets results in interplanetary spacecraft that are prohibitive in terms of Initial Mass in Low- Earth Orbit (IMLEO) and cost. For example, using chemical rockets to return samples from Europa appears to be technically impractical, as it would require large delta V and launch vehicle capabilities. On the other hand, use of nuclear thermal rockets will significantly reduce IMLEO and, subsequently, costs. Moreover, nuclear thermal rockets can utilize extraterrestrial resources as propellants, an option not practical with chemical rockets. This "refueling" capability would enable nuclear rockets to carry out very high-energy missions, such as the return of large

The Galilean Satellites

NASA Image and Video Library

1997-11-18

This composite includes the four largest moons of Jupiter which are known as the Galilean satellites. From left to right, the moons shown are Ganymede, Callisto, Io, and Europa. The Galilean satellites were first seen by the Italian astronomer Galileo Galilei in 1610. In order of increasing distance from Jupiter, Io is closest, followed by Europa, Ganymede, and Callisto. The order of these satellites from the planet Jupiter helps to explain some of the visible differences among the moons. Io is subject to the strongest tidal stresses from the massive planet. These stresses generate internal heating which is released at the surface and makes Io the most volcanically active body in our solar system. Europa appears to be strongly differentiated with a rock/iron core, an ice layer at its surface, and the potential for local or global zones of water between these layers. Tectonic resurfacing brightens terrain on the less active and partially differentiated moon Ganymede. Callisto, furthest from Jupiter, appears heavily cratered at low resolutions and shows no evidence of internal activity. North is to the top of this composite picture in which these satellites have all been scaled to a common factor of 10 kilometers (6 miles) per picture element. The Solid State Imaging (CCD) system aboard NASA's Galileo spacecraft obtained the Io and Ganymede images in June 1996, while the Europa images were obtained in September 1996. Because Galileo focuses on high resolution imaging of regional areas on Callisto rather than global coverage, the portrait of Callisto is from the 1979 flyby of NASA's Voyager spacecraft. http://photojournal.jpl.nasa.gov/catalog/PIA00601

JUICE: a European mission to Jupiter and its icy moons

NASA Astrophysics Data System (ADS)

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

2013-09-01

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

Strong tidal dissipation in Io and Jupiter from astrometric observations.

PubMed

Lainey, Valéry; Arlot, Jean-Eudes; Karatekin, Ozgür; Van Hoolst, Tim

2009-06-18

Io is the volcanically most active body in the Solar System and has a large surface heat flux. The geological activity is thought to be the result of tides raised by Jupiter, but it is not known whether the current tidal heat production is sufficiently high to generate the observed surface heat flow. Io's tidal heat comes from the orbital energy of the Io-Jupiter system (resulting in orbital acceleration), whereas dissipation of energy in Jupiter causes Io's orbital motion to decelerate. Here we report a determination of the tidal dissipation in Io and Jupiter through its effect on the orbital motions of the Galilean moons. Our results show that the rate of internal energy dissipation in Io (k(2)/Q = 0.015 +/- 0.003, where k(2) is the Love number and Q is the quality factor) is in good agreement with the observed surface heat flow, and suggest that Io is close to thermal equilibrium. Dissipation in Jupiter (k(2)/Q = (1.102 +/- 0.203) x 10(-5)) is close to the upper bound of its average value expected from the long-term evolution of the system, and dissipation in extrasolar planets may be higher than presently assumed. The measured secular accelerations indicate that Io is evolving inwards, towards Jupiter, and that the three innermost Galilean moons (Io, Europa and Ganymede) are evolving out of the exact Laplace resonance.

About Jupiter's Reflectance Function in JunoCam Images

NASA Astrophysics Data System (ADS)

Eichstaedt, G.; Orton, G. S.; Momary, T.; Hansen, C. J.; Caplinger, M.

2017-09-01

NASA's Juno spacecraft has successfully completed several perijove passes. JunoCam is Juno's visible light and infrared camera. It was added to the instrument complement to investigate Jupiter's polar regions, and for education and public outreach purposes. Images of Jupiter taken by JunoCam have been revealing effects that can be interpreted as caused by a haze layer. This presumed haze layer appears to be structured, and it partially obscures Jupiter's cloud top. With empirical investigation of Jupiter's reflectance function we intend to separate light contributed by haze from light reflected off Jupiter's cloud tops, enabling both layers to be investigated separately.

Jupiter Equatorial Region

NASA Image and Video Library

1998-03-06

This photographic mosaic of images from NASA's Galileo spacecraft covers an area of 34,000 kilometers by 22,000 kilometers (about 21,100 by 13,600 miles) in Jupiter's equatorial region. The dark region near the center of the mosaic is an equatorial "hotspot" similar to the site where the Galileo Probe parachuted into Jupiter's atmosphere in December 1995. These features are holes in the bright, reflective, equatorial cloud layer where heat from Jupiter's deep atmosphere can pass through. The circulation patterns observed here along with the composition measurements from the Galileo Probe suggest that dry air may be converging and sinking over these regions, maintaining their cloud-free appearance. The bright oval in the upper right of the mosaic as well as the other smaller bright features are examples of upwelling of moist air and condensation. These images were taken on December 17, 1996, at a range of 1.5 million kilometers (about 930,000 miles) by the Solid State Imaging camera system aboard Galileo. North is at the top. The mosaic covers latitudes 1 to 19 degrees and is centered at longitude 336 degrees west. The smallest resolved features are tens of kilometers in size. http://photojournal.jpl.nasa.gov/catalog/PIA00604

The galilean satellites and Jupiter: Voyager 2 imaging science results

USGS Publications Warehouse

Smith, B.A.; Soderblom, L.A.; Beebe, R.; Boyce, J.; Briggs, G.; Carr, M.; Collins, S.A.; Cook, A.F.; Danielson, G.E.; Davies, M.E.; Hunt, G.E.; Ingersoll, A.; Johnson, T.V.; Masursky, H.; McCauley, J.; Morrison, D.; Owen, Timothy W.; Sagan, C.; Shoemaker, E.M.; Strom, R.; Suomi, V.E.; Veverka, J.

1979-01-01

Voyager 2, during its encounter with the Jupiter system, provided images that both complement and supplement in important ways the Voyager 1 images. While many changes have been observed in Jupiter's visual appearance, few, yet significant, changes have been detected in the principal atmospheric currents. Jupiter's ring system is strongly forward scattering at visual wavelengths and consists of a narrow annulus of highest particle density, within which is a broader region in which the density is lower. On Io, changes are observed in eruptive activity, plume structure, and surface albedo patterns. Europa's surface retains little or no record of intense meteorite bombardment, but does reveal a complex and, as yet, little-understood system of overlapping bright and dark linear features. Ganymede is found to have at least one unit of heavily cratered terrain on a surface that otherwise suggests widespread tectonism. Except for two large ringed basins, Callisto's entire surface is heavily cratered. Copyright ?? 1979 AAAS.

NASA Reveals New Discoveries on Oceans Beyond Earth During Science Briefing

NASA Image and Video Library

2017-04-13

During a NASA science briefing on April 13, representatives from the agency discussed new results about ocean worlds in our solar system based on data gathered by NASA’s Cassini spacecraft and the Hubble Space Telescope. The two veteran missions are providing tantalizing new details about icy, ocean-bearing moons of Jupiter and Saturn, further enhancing the scientific interest of these and other "ocean worlds" in our solar system and beyond. New research from Cassini indicates that hydrogen gas, which could potentially provide a chemical energy source for life, is pouring into the ocean of Saturn's icy moon Enceladus from hydrothermal vents in the seafloor. The Cassini spacecraft detected the hydrogen in the plume of gas and icy material spraying from Enceladus during its deepest dive through the plume on Oct. 28, 2015.This means that ocean microbes -- if any exist there -- could use the hydrogen to produce energy NASA’s Hubble Space Telescope saw a probable plume of material erupting from the moon’s surface on 2016, at the same location where Hubble saw evidence of a plume in 2014. These images bolster evidence that the Europa plumes could be a real phenomenon, flaring up intermittently in the same region on the moon's surface. Both Cassini and Hubble investigations are laying the groundwork for NASA's Europa Clipper mission, which is being planned for launch in the 2020s.

Jupiter Scar in Infrared

NASA Image and Video Library

2011-01-26

These infrared images obtained from NASA Infrared Telescope Facility in Mauna Kea, Hawaii, show before and aftereffects from particle debris in Jupiter atmosphere after an object hurtled into the atmosphere on July 19, 2009.

To determine ice layer thickness of Europa by high energy neutrino

NASA Astrophysics Data System (ADS)

Shoji, D.; Kurita, K.; Tanaka, H. K.

2010-12-01

Europa, the second closest Galilean satellite is one of the targets which are suspected to have an internal ocean. Detection and characterization of the internal ocean is one of the main subjects for Europa orbiter exploration. Although the gravitational data has shown the thickness of the surface H2O layer of 80-170km[1], it can not determine the phase of H2O. The variations in the magnetic field associated with the induced current in the internal ocean can determine the thickness of the layer of ice if satellite's orbits satisfy the required conditions. Observations of tidal amplitude forced by Jupiter can also resolve the thickness of the surface lithosphere[2]. At moment because of the lack of observational constraints there exist two contrasting models:thick ice layer model and thin model. Here we propose new method to detect the ocean directly based on the radiation by high energy neutrino interacted with matter. Schaefer et al[3] have proposed a similar method to determine ice layer thickness. We will focus on the detection of internal ocean for Europa and present the method is suitable for actual situations of Europa exploration by numerical simulations. Neutrino is famous for its traveling at long distance without any interaction with matter. When high energy neutrinos traverse in Europa hadronic showers are produced by the weak interaction with the nucleons that makes the body of Europa. These hadronic showers induces excess electrons. Because of these excess electrons, Cherenkov photons are emitted. When this radiation occurs in the ice layer, radiations whose wave length is over 10cm should be coherent because the scale of the shower becomes small (a few cm) in the ice, which is called as Askaryan effect[3]. Thus, the intensity of the radiation whose frequency is a few GHz should be enhanced. Since ice has a much longer attenuation length than water, the radiations which occur in the surface ice layer could be detected by the antenna outside Europa but

True polar wander on Europa from global-scale small-circle depressions.

PubMed

Schenk, Paul; Matsuyama, Isamu; Nimmo, Francis

2008-05-15

The tectonic patterns and stress history of Europa are exceedingly complex and many large-scale features remain unexplained. True polar wander, involving reorientation of Europa's floating outer ice shell about the tidal axis with Jupiter, has been proposed as a possible explanation for some of the features. This mechanism is possible if the icy shell is latitudinally variable in thickness and decoupled from the rocky interior. It would impose high stress levels on the shell, leading to predictable fracture patterns. No satisfactory match to global-scale features has hitherto been found for polar wander stress patterns. Here we describe broad arcuate troughs and depressions on Europa that do not fit other proposed stress mechanisms in their current position. Using imaging from three spacecraft, we have mapped two global-scale organized concentric antipodal sets of arcuate troughs up to hundreds of kilometres long and 300 m to approximately 1.5 km deep. An excellent match to these features is found with stresses caused by an episode of approximately 80 degrees true polar wander. These depressions also appear to be geographically related to other large-scale bright and dark lineaments, suggesting that many of Europa's tectonic patterns may also be related to true polar wander.

Hubble Space Telescope observations of Europa in and out of eclipse

USGS Publications Warehouse

Sparks, W.B.; McGrath, M.; Hand, K.; Ford, H.C.; Geissler, P.; Hough, J.H.; Turner, E.L.; Chyba, C.F.; Carlson, R.; Turnbull, M.

2010-01-01

Europa is a prime target for astrobiology and has been prioritized as the next target for a National Aeronautics and Space Administration flagship mission. It is important, therefore, that we advance our understanding of Europa, its ocean and physical environment as much as possible. Here, we describe observations of Europa obtained during its orbital eclipse by Jupiter using the Hubble Space Telescope. We obtained Advanced Camera for Surveys Solar Blind Channel far ultraviolet low-resolution spectra that show oxygen line emission both in and out of eclipse. We also used the Wide-Field and Planetary Camera-2 and searched for broad-band optical emission from fluorescence of the surface material, arising from the very high level of incident energetic particle radiation on ices and potentially organic substances. The high-energy particle radiation at the surface of Europa is extremely intense and is responsible for the production of a tenuous oxygen atmosphere and associated FUV line emission. Approximately 50% of the oxygen emission lasts at least a few hours into the eclipse. We discuss the detection limits of the optical emission, which allow us to estimate the fraction of incident energy reradiated at optical wavelengths, through electron-excited emission, Cherenkov radiation in the ice and fluorescent processes. ?? 2010 Cambridge University Press.

NASA Ames UV-LED Poster Overview

NASA Technical Reports Server (NTRS)

Jaroux, Belgacem Amar

2015-01-01

UV-LED is a small satellite technology demonstration payload being flown on the Saudisat-4 spacecraft that is demonstrating non-contacting charge control of an isolated or floating mass using new solid-state ultra-violet light emitting diodes (UV-LEDs). Integrated to the rest of the spacecraft and launched on a Dnepr in June 19, 2014, the project is a collaboration between the NASA Ames Research Center (ARC), Stanford University, and King Abdulaziz City for Science and Technology (KACST). Beginning with its commissioning in December, 2015, the data collected by UV-LED have validated a novel method of charge control that will improve the performance of drag-free spacecraft allowing for concurrent science collection during charge management operations as well as reduce the mass, power and volume required while increasing lifetime and reliability of a charge management subsystem. UV-LED continues to operate, exploring new concepts in non-contacting charge control and collecting data crucial to understanding the lifetime of ultra-violet light emitting diodes in space. These improvements are crucial to the success of ground breaking missions such as LISA and BBO, and demonstrates the ability of low cost small satellite missions to provide technological advances that far exceed mission costs.

Analysis of Preferred Directions in Phase Space for Tidal Measurements at Europa

NASA Astrophysics Data System (ADS)

Boone, D.; Scheeres, D. J.

2012-12-01

The NASA Jupiter Europa Orbiter mission requires a circular, near-polar orbit to measure Europa's Love numbers, geophysical coefficients which give insight into whether a liquid ocean exists. This type of orbit about planetary satellites is known to be unstable. The effects of Jupiter's tidal gravity are seen in changes in Europa's gravity field and surface deformation, which are sensed through doppler tracking over time and altimetry measurements respectively. These two measurement types separately determine the h and k Love numbers, a combination of which bounds how thick the ice shell of Europa is and whether liquid water is present. This work shows how the properties of an unstable periodic orbit about Europa generate preferred measurement directions in position and velocity phase space for the orbit determination process. We generate an error covariance over seven days for the orbiter state and science parameters using a periodic orbit and then disperse the orbit initial conditions in a Monte Carlo simulation according to this covariance. The dispersed orbits are shown to have a bias toward longer lifetimes and we discuss this as an effect of the stable and unstable manifolds of the periodic orbit. Using an epoch formulation of a square-root information filter, measurements aligned with the unstable manifold mapped back in time add more information to the orbit determination process than measurements aligned with the stable manifold. This corresponds to a contraction in the uncertainty of the estimate of the desired parameters, including the Love numbers. We demonstrate this mapping mathematically using a representation of the State Transition Matrix involving its eigenvectors and eigenvalues. Then using the properties of left and right eigenvectors, we show how measurements in the orbit determination process are mapped in time leading to a concentration of information at epoch. We present examples of measurements taken on different time schedules to show the

Close-up of Jupiter's Great Red Spot

NASA Image and Video Library

2017-07-12

This enhanced-color image of Jupiter's Great Red Spot was created by citizen scientist Jason Major using data from the JunoCam imager on NASA's Juno spacecraft. The image was taken on July 10, 2017 at 07:10 p.m. PDT (10:10 p.m. EDT), as the Juno spacecraft performed its 7th close flyby of Jupiter. At the time the image was taken, the spacecraft was about 8,648 miles (13,917 kilometers) from the tops of the clouds of the planet. https://photojournal.jpl.nasa.gov/catalog/PIA21772

Sharpening Up Jupiter

NASA Astrophysics Data System (ADS)

2008-10-01

, MAD project manager Enrico Marchetti and Sébastien Tordo from the MAD team tracked two of Jupiter's largest moons, Europa and Io - one on each side of the planet - to provide a good correction across the full disc of the planet. "It was the most challenging observation we performed with MAD, because we had to track with high accuracy two moons moving at different speeds, while simultaneously chasing Jupiter," says Marchetti. With this unique series of images, the team found a major alteration in the brightness of the equatorial haze, which lies in a 16 000-kilometre wide belt over Jupiter's equator [2]. More sunlight reflecting off upper atmospheric haze means that the amount of haze has increased, or that it has moved up to higher altitudes. "The brightest portion had shifted south by more than 6000 kilometres," explains team member Mike Wong. This conclusion came after comparison with images taken in 2005 by Wong and colleague Imke de Pater using the Hubble Space Telescope. The Hubble images, taken at infrared wavelengths very close to those used for the VLT study, show more haze in the northern half of the bright Equatorial Zone, while the 2008 VLT images show a clear shift to the south. "The change we see in the haze could be related to big changes in cloud patterns associated with last year's planet-wide upheaval, but we need to look at more data to narrow down precisely when the changes occurred," declares Wong.

Surface Modification and Surface - Subsurface Exchange Processes on Europa

NASA Astrophysics Data System (ADS)

Phillips, C. B.; Molaro, J.; Hand, K. P.

2017-12-01

The surface of Jupiter's moon Europa is modified by exogenic processes such as sputtering, gardening, radiolysis, sulfur ion implantation, and thermal processing, as well as endogenic processes including tidal shaking, mass wasting, and the effects of subsurface tectonic and perhaps cryovolcanic activity. New materials are created or deposited on the surface (radiolysis, micrometeorite impacts, sulfur ion implantation, cryovolcanic plume deposits), modified in place (thermal segregation, sintering), transported either vertically or horizontally (sputtering, gardening, mass wasting, tectonic and cryovolcanic activity), or lost from Europa completely (sputtering, plumes, larger impacts). Some of these processes vary spatially, as visible in Europa's leading-trailing hemisphere brightness asymmetry. Endogenic geologic processes also vary spatially, depending on terrain type. The surface can be classified into general landform categories that include tectonic features (ridges, bands, cracks); disrupted "chaos-type" terrain (chaos blocks, matrix, domes, pits, spots); and impact craters (simple, complex, multi-ring). The spatial distribution of these terrain types is relatively random, with some differences in apex-antiapex cratering rates and latitudinal variation in chaos vs. tectonic features. In this work, we extrapolate surface processes and rates from the top meter of the surface in conjunction with global estimates of transport and resurfacing rates. We combine near-surface modification with an estimate of surface-subsurface (and vice versa) transport rates for various geologic terrains based on an average of proposed formation mechanisms, and a spatial distribution of each landform type over Europa's surface area. Understanding the rates and mass balance for each of these processes, as well as their spatial and temporal variability, allows us to estimate surface - subsurface exchange rates over the average surface age ( 50myr) of Europa. Quantifying the timescale

Acetylene around Jupiter Poles

NASA Image and Video Library

2010-12-29

This graphic shows the distribution of the organic molecule acetylene at the north and south poles of Jupiter, based on data obtained by NASA Cassini spacecraft in early January 2001. Movie is available at the Photojournal.

Voyager picture of Jupiter

NASA Technical Reports Server (NTRS)

1998-01-01

NASA's Voyager 1 took this picture of the planet Jupiter on Saturday, Jan. 6, the first in its three-month-long, close-up investigation of the largest planet. The spacecraft, flying toward a March 5 closest approach, was 35.8 million miles (57.6 million kilometers) from Jupiter and 371.7 million miles (598.2 million kilometers) from Earth when the picture was taken. As the Voyager cameras begin their meteorological surveillance of Jupiter, they reveal a dynamic atmosphere with more convective structure than had previously been thought. While the smallest atmospheric features seen in this picture are still as large as 600 miles (1,000 kilometers) across, Voyager will be able to detect individual storm systems as small as 3 miles (5 kilometers) at closest approach. The Great Red Spot can be seen near the limb at the far right. Most of the other features are too small to be seen in terrestrial telescopes. This picture was transmitted to the Jet Propulsion Laboratory through the Deep Space Network's tracking station at Madrid, Spain. The Voyager Project is managed for NASA by Caltech's Jet Propulsion Laboratory.

NASA Facts, Voyager.

ERIC Educational Resources Information Center

National Aeronautics and Space Administration, Washington, DC. Educational Programs Div.

This document is one of a series of publications of the National Aeronautics and Space Administration (NASA) on facts about the exploration of Jupiter and Saturn. This NASA mission consists of two unmanned Voyager spacecrafts launched in August and September of 1977, and due to arrive at Jupiter in 1979. An account of the scientific equipment…

Prospects For Earth-Based Measurements Of Europa's Librations

NASA Astrophysics Data System (ADS)

Margot, Jean-Luc; Campbell, D. B.; Peale, S. J.

2010-10-01

The exploration of Europa is of great interest because it may be hospitable to certain life forms [1]. Several lines of evidence suggest that a subsurface ocean exists beneath an icy shell [2,3], but there is debate about the thickness of the shell [4], which impacts Europa's astrobiological potential. As in the case of Mercury, it may be possible to determine whether an outer shell is decoupled from the interior and to evaluate the shell thickness by measuring the amplitude of forced longitude librations [5,6]. In the simplest configuration of a rigid shell decoupled from a spherically symmetric interior, the libration amplitude is amplified from the nominal value of 18" by C/Cs, where C is the polar moment of inertia of the body and Cs is that of the outer shell that participates in the librations. For a 100-km thick shell, the libration amplitude would reach 200", an estimate that remains valid even in the presence of gravitational coupling between asymmetrical layers [7]. If there are significant departures from rigid behavior, the shell may deform with the ocean underneath and exhibit a libration amplitude of 52" [8]. Europa reaches closest approach in October 2011, offering a once-in-a-decade opportunity to measure spin rate variations by tracking radar speckles, as advocated by Holin [9,10]. Librations of a rigid shell thinner than 100 km would be detectable. We will describe the experimental design and expected sensitivity. References: [1] NRC, Europa Science Strategy, 1999. [2,3] Kivelson et al, Greeley et al, in Jupiter, CUP, 2004. [4] Greenberg, Unmasking Europa, Praxis, 2008. [5] Peale, Nature 262, 1976. [6] Margot et al, Science 316, 2007. [7] van Hoolst et al, Icarus 195, 2008. [8] Goldreich and Mitchell, Icarus, in press. [9] Green, in Radar Astronomy, McGraw-Hill, 1968. [10] Holin, Radiophys. Quant. Elec. 31, 1988.

Europa's surface radiation environment and considerations for in-situ sampling and biosignature detection

NASA Astrophysics Data System (ADS)

Nordheim, T.; Paranicas, C.; Hand, K. P.

2017-12-01

Jupiter's moon Europa is embedded deep within the Jovian magnetosphere and is thus exposed to bombardment by charged particles, from thermal plasma to more energetic particles at radiation belt energies. In particular, energetic charged particles are capable of affecting the uppermost layer of surface material on Europa, in some cases down to depths of several meters (Johnson et al., 2004; Paranicas et al., 2009, 2002). Examples of radiation-induced surface alteration include sputtering, radiolysis and grain sintering; processes that are capable of significantly altering the physical properties of surface material. Radiolysis of surface ices containing sulfur-bearing contaminants from Io has been invoked as a possible explanation for hydrated sulfuric acid detected on Europa's surface (Carlson et al., 2002, 1999) and radiolytic production of oxidants represents a potential source of energy for life that could reside within Europa's sub-surface ocean (Chyba, 2000; Hand et al., 2007; Johnson et al., 2003; Vance et al., 2016). Accurate knowledge of Europa's surface radiation environment is essential to the interpretation of space and Earth-based observations of Europa's surface and exosphere. Furthermore, future landed missions may seek to sample endogenic material emplaced on Europa's surface to investigate its chemical composition and to search for biosignatures contained within. Such material would likely be sampled from the shallow sub-surface, and thus, it becomes crucial to know to which degree this material is expected to have been radiation processed.Here we will present modeling results of energetic electron and proton bombardment of Europa's surface, including interactions between these particles and surface material. In addition, we will present predictions for biosignature destruction at different geographical locations and burial depths and discuss the implications of these results for surface sampling by future missions to Europa's surface.

The Plasma Instrument for Magnetic Sounding (PIMS) onboard the Europa Clipper Mission

NASA Astrophysics Data System (ADS)

Westlake, Joseph H.; McNutt, Ralph L.; Kasper, Justin C.; Rymer, Abigail; Case, Anthony; Battista, Corina; Cochrane, Corey; Coren, David; Crew, Alexander; Grey, Matthew; Jia, Xianzhe; Khurana, Krishan; Kim, Cindy; Kivelson, Margaret G.; Korth, Haje; Krupp, Norbert; Paty, Carol; Roussos, Elias; Stevens, Michael; Slavin, James A.; Smith, Howard T.; Saur, Joachim

2017-10-01

Europa is embedded in a complex Jovian magnetospheric plasma, which rotates with the tilted planetary field and interacts dynamically with Europa’s ionosphere affecting the magnetic induction signal. Plasma from Io’s temporally varying torus diffuses outward and mixes with the charged particles in Europa’s own torus producing highly variable plasma conditions. Onboard the Europa Clipper spacecraft the Plasma Instrument for Magnetic Sounding (PIMS) works in conjunction with the Interior Characterization of Europa using Magnetometry (ICEMAG) investigation to probe Europa’s subsurface ocean. This investigation exploits currents induced in Europa’s interior by the moon’s exposure to variable magnetic fields in the Jovian system to infer properties of Europa’s subsurface ocean such as its depth, thickness, and conductivity. This technique was successfully applied to Galileo observations and demonstrated that Europa indeed has a subsurface ocean. While these Galileo observations contributed to the renewed interest in Europa, due to limitations in the observations the results raised major questions that remain unanswered. PIMS will greatly refine our understanding of Europa’s global liquid ocean by accounting for contributions to the magnetic field from plasma currents.The Europa Clipper mission is equipped with a sophisticated suite of 9 instruments to study Europa's interior and ocean, geology, chemistry, and habitability from a Jupiter orbiting spacecraft. PIMS on Europa Clipper is a Faraday Cup based plasma instrument whose heritage dates back to the Voyager spacecraft. PIMS will measure the plasma that populates Jupiter’s magnetosphere and Europa’s ionosphere. The science goals of PIMS are to: 1) estimate the ocean salinity and thickness by determining Europa’s magnetic induction response, corrected for plasma contributions; 2) assess mechanisms responsible for weathering and releasing material from Europa’s surface into the atmosphere and

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.

Europa's small impactor flux and seismic detection predictions

NASA Astrophysics Data System (ADS)

Tsuji, Daisuke; Teanby, Nicholas A.

2016-10-01

Europa is an attractive target for future lander missions due to its dynamic surface and potentially habitable sub-surface environment. Seismology has the potential to provide powerful new constraints on the internal structure using natural sources such as faults or meteorite impacts. Here we predict how many meteorite impacts are likely to be detected using a single seismic station on Europa to inform future mission planning efforts. To this end, we derive: (1) the current small impactor flux on Europa from Jupiter impact rate observations and models; (2) a crater diameter versus impactor energy scaling relation for icy moons by merging previous experiments and simulations; and (3) scaling relations for seismic signal amplitudes as a function of distance from the impact site for a given crater size, based on analogue explosive data obtained on Earth's ice sheets. Finally, seismic amplitudes are compared to predicted noise levels and seismometer performance to determine detection rates. We predict detection of 0.002-20 small local impacts per year based on P-waves travelling directly through the ice crust. Larger regional and global-scale impact events, detected through mantle-refracted waves, are predicted to be extremely rare (10-8-1 detections per year), so are unlikely to be detected by a short duration mission. Estimated ranges include uncertainties from internal seismic attenuation, impactor flux, and seismic amplitude scaling. Internal attenuation is the most significant unknown and produces extreme uncertainties in the mantle-refracted P-wave amplitudes. Our nominal best-guess attenuation model predicts 0.002-5 local direct P detections and 6 × 10-6-0.2 mantle-refracted detections per year. Given that a plausible Europa landed mission will only last around 30 days, we conclude that impacts should not be relied upon for a seismic exploration of Europa. For future seismic exploration, faulting due to stresses in the rigid outer ice shell is likely to be a

Search for volatiles on icy satellites. I. Europa

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

Brown, R.H.; Cruikshank, D.P.; Tokunaga, A.T.

1988-05-01

NASA IRTF reflectance spectra of unprecedented precision, obtained for the leading and trailing sides of Europa, are presently noted to no longer show the apparent absorptions seen in 1980 and 1985. It is presently suggested that if the weak absorptions seen in the 1980 and 1985 data are real, they may indicate the transient spectroscopic presence of a molecular component on Europa's trailing side that differs from the water ice known to be the dominant constituent of the surface. 33 references.

Jupiter Shakes it Off

NASA Image and Video Library

2012-10-17

Jupiter has been suffering more impacts over the last four years than ever previously observed, including this meteoroid impact on Sept. 10, 2012. Right-hand image is an infrared image NASA Infrared Telescope Facility on Mauna Kea, Hawaii.

Trajectory Design for the Europa Clipper Mission Concept

NASA Technical Reports Server (NTRS)

Buffington, Brent

2014-01-01

Europa is one of the most scientifically intriguing targets in planetary science due to its potential suitability for extant life. As such, NASA has funded the California Institute of Technology Jet Propulsion Laboratory and the Johns Hopkins University Applied Physics Laboratory to jointly determine and develop the best mission concept to explore Europa in the near future. The result of nearly 4 years of work--the Europa Clipper mission concept--is a multiple Europa flyby mission that could efficiently execute a number of high caliber science investigations to meet Europa science priorities specified in the 2011 NRC Decadal Survey, and is capable of providing reconnaissance data to maximize the probability of both a safe landing and access to surface material of high scientific value for a future Europa lander. This paper will focus on the major enabling component for this mission concept--the trajectory. A representative trajectory, referred to as 13F7-A21, would obtain global-regional coverage of Europa via a complex network of 45 flybys over the course of 3.5 years while also mitigating the effects of the harsh Jovian radiation environment. In addition, 5 Ganymede and 9 Callisto flybys would be used to manipulate the trajectory relative to Europa. The tour would reach a maximum Jovicentric inclination of 20.1 deg. have a deterministic (Delta)V of 164 m/s (post periapsis raise maneuver), and a total ionizing dose of 2.8 Mrad (Si).

Planetary Science Enabled by High Power Ion Propulsion Systems from NASA's Prometheus Program

NASA Astrophysics Data System (ADS)

Cooper, John

2004-11-01

NASA's Prometheus program seeks to develop new generations of spacecraft nuclear-power and ion propulsion systems for applications to future planetary missions. The Science Definition Team for the first mission in the Prometheus series, the Jupiter Icy Moons Orbiter (JIMO), has defined science objectives for in-situ orbital exploration of the icy Galilean moons (Europa, Ganymede, Callisto) and the Jovian magnetosphere along with remote observations of Jupiter's atmosphere and aurorae, the volcanic moon Io, and other elements of the Jovian system. Important to this forum is that JIMO power and propulsion systems will need to be designed to minimize magnetic, radio, neutral gas, and plasma backgrounds that might otherwise interfere with achievement of mission science objectives. Another potential Prometheus mission of high science interest would be an extended tour of primitive bodies in the solar system, including asteroids, Jupiter family comets, Centaurs, and Kuiper Belt Objects (KBO). The final landed phase of this mission might include an active keplerian experiment for detectable (via downlink radio doppler shift) acceleration of a small kilometer-size Centaur or KBO object, likely the satellite of a larger object observable from Earth. This would have obvious application to testing of mitigation techniques for Earth impact hazards.

Jupiter 7th Pearl

NASA Image and Video Library

2016-12-14

This image, taken by the JunoCam imager on NASA's Juno spacecraft, highlights the seventh of eight features forming a 'string of pearls' on Jupiter -- massive counterclockwise rotating storms that appear as white ovals in the gas giant's southern hemisphere. Since 1986, these white ovals have varied in number from six to nine. There are currently eight white ovals visible. Since 1986, these white ovals have varied in number from six to nine. There are currently eight white ovals visible. The image was taken on Dec. 11, 2016, at 9:27 a.m. PST (12:27 EST) as the Juno spacecraft performed its third close flyby of the planet. At the time the image was taken, the spacecraft was about 15,300 miles (24,600 kilometers) from Jupiter. http://photojournal.jpl.nasa.gov/catalog/PIA21219

Jupiter Ring Halo

NASA Image and Video Library

1998-03-26

A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (km) per picture element (pixel) along the rings; however, because the spacecraft was only about 0.5 degrees above the ring plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow peering back toward the Sun; the ring was approximately 2,300,000 kilometers (km) away. The arc on the far right of the image is produced by sunlight scattered by small particles comprising Jupiter's upper atmospheric haze. The ring also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age. Jupiter's ring system is composed of three parts -- a flat main ring, a lenticular halo interior to the main ring, and the gossamer ring, which lies exterior to the main ring. The near and far arms of Jupiter's main ring extend horizontally across the mosaic, joining together at the ring's ansa, on the far left side of the figure. The near arm of the ring appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow. A faint mist of particles can be seen above and below the main rings; this vertically extended, toroidal "halo" is unusual in planetary rings, and is probably caused by electromagnetic forces which can push small grains out of the ring plane. Halo material is present across this entire image, implying that it reaches more than 27,000 km above the ring plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. In order to accentuate faint features in the image, different brightnesses are shown through color, with the brightest being

Juno's Eighth Close Approach to Jupiter

NASA Image and Video Library

2017-09-08

This series of enhanced-color images shows Jupiter up close and personal, as NASA's Juno spacecraft performed its eighth flyby of the gas giant planet. The images were obtained by JunoCam. From left to right, the sequence of images taken on Sept. 1, 2017 from 3:03 p.m. to 3:11 p.m. PDT (6:03 p.m. to 6:11 p.m. EDT). At the times the images were taken, the spacecraft ranged from 7,545 to 14,234 miles (12,143 to 22,908 kilometers) from the tops of the clouds of the planet at a latitude range of -28.5406 to -44.4912 degrees. Points of Interest include "Dalmatian Zone/Eye of Odin," "Dark Eye/STB Ghost East End," "Coolest Place on Jupiter," and "Renslow/Hurricane Rachel." The final image in the series on the right shows Jupiter's south pole coming into view. https://photojournal.jpl.nasa.gov/catalog/PIA21780

Juno First Slice of Jupiter

NASA Image and Video Library

2016-10-19

This composite image depicts Jupiter's cloud formations as seen through the eyes of Juno's Microwave Radiometer (MWR) instrument as compared to the top layer, a Cassini Imaging Science Subsystem image of the planet. The MWR can see a couple of hundred miles (kilometers) into Jupiter's atmosphere with its largest antenna. The belts and bands visible on the surface are also visible in modified form in each layer below. http://photojournal.jpl.nasa.gov/catalog/PIA21107

What Juno will see at Jupiter South Pole Simulation

NASA Image and Video Library

2011-08-03

This simulated view of the south pole of Jupiter illustrates the unique perspective of NASA Juno mission. Juno polar orbit will allow its camera, called JunoCam, to image Jupiter clouds from a vantage point never accessed by other spacecraft.

Jupiter's ring

NASA Technical Reports Server (NTRS)

1979-01-01

First evidence of a ring around the planet Jupiter is seen in this photograph taken by Voyager 1 on March 4, 1979. The multiple exposure of the extremely thin faint ring appears as a broad light band crossing the center of the picture. The edge of the ring is 1,212,000 km from the spacecraft and 57,000 km from the visible cloud deck of Jupiter. The background stars look like broken hair pins because of spacecraft motion during the 11 minute 12 second exposure. The wavy motion of the star trails is due to the ultra-slow natural oscillation of the spacecraft (with a period of 78 seconds). The black dots are geometric calibration points in the camera. The ring thickness is estimated to be 30 km or less. The photograph was part of a sequence planned to search for such rings in Jupiter's equatorial plane. The ring has been invisible from Earth because of its thinness and its transparency when viewed at any angle except straight on. JPL manages and controls the Voyager Project for NASA's Office of Space Science.

The tails of the satellite auroral footprints at Jupiter

NASA Astrophysics Data System (ADS)

Bonfond, B.; Saur, J.; Grodent, D.; Badman, S. V.; Bisikalo, D.; Shematovich, V.; Gérard, J.-C.; Radioti, A.

2017-08-01

The electromagnetic interaction between Io, Europa, and Ganymede and the rotating plasma that surrounds Jupiter has a signature in the aurora of the planet. This signature, called the satellite footprint, takes the form of a series of spots located slightly downstream of the feet of the field lines passing through the moon under consideration. In the case of Io, these spots are also followed by an extended tail in the downstream direction relative to the plasma flow encountering the moon. A few examples of a tail for the Europa footprint have also been reported in the northern hemisphere. Here we present a simplified Alfvénic model for footprint tails and simulations of vertical brightness profiles for various electron distributions, which favor such a model over quasi-static models. We also report here additional cases of Europa footprint tails, in both hemispheres, even though such detections are rare and difficult. Furthermore, we show that the Ganymede footprint can also be followed by a similar tail. Finally, we present a case of a 320° long Io footprint tail, while other cases in similar configurations do not display such a length.

Motion in Jupiter's Atmospheric Vortices (Near-infrared filters)

NASA Technical Reports Server (NTRS)

1997-01-01

Two frame 'movie' of a pair of vortices in Jupiter's southern hemisphere. The two frames are separated by ten hours. The right oval is rotating counterclockwise, like other anticyclonic bright vortices in Jupiter's atmosphere. The left vortex is a cyclonic (clockwise) vortex. The differences between them (their brightness, their symmetry, and their behavior) are clues to how Jupiter's atmosphere works. The frames span about fifteen degrees in latitude and longitude and are centered at 141 degrees west longitude and 36 degrees south planetocentric latitude. Both vortices are about 3500 kilometers in diameter in the north-south direction.

The images were taken in near infrared light at 756 nanometers and show clouds that are at a pressure level of about 1 bar in Jupiter's atmosphere. North is at the top. The smallest resolved features are tens of kilometers in size. These images were taken on May 7, 1997, at a range of 1.5 million kilometers by the Solid State Imaging system on NASA's Galileo spacecraft.

The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

Jupiter Polar Winds Movie

NASA Technical Reports Server (NTRS)

2001-01-01

latitude and covering 360 degrees in longitude. The movie consists of 84 such maps, spanning 70 Earth days in time or 168 Jupiter rotations.

Transforming the cylindrical maps into polar stereographic projections produces a movie of what Jupiter would look like if viewed from the pole. Jupiter's alternating eastward and westward jet streams flow in concentric rings around the pole, with equatorial motions visible in the corners. The dark features flowing counterclockwise near the equator are'hot spots' where cloud cover is relatively thin.

The high-latitude movements call into question one notion concerning wind circulation on Jupiter. The model in question suggests that Jupiter'a alternating bands of east-west winds are the exposed edges of deeper rotating cylinders that extend north-south through the planet. However, the east-west winds that the movie shows in polar regions don't fit that model. The cylinders whose edges would form those bands would have to go through the innermost portion of the planet, where the cylinders' different rotations could not be maintained. Jupiter's wind pattern may involve a mix of rotation-on-cylinders near the equator and some other circulation mechanism near the poles.

For more information, see the Cassini Project home page, http://www.jpl.nasa.gov/cassini/ and the Cassini Imaging Team home page, http://ciclops.lpl.arizona.edu/ciclops/ .

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.

Complexity analysis of the cost effectiveness of PI-led NASA science missions

NASA Astrophysics Data System (ADS)

Yoshida, J.; Cowdin, M.; Mize, T.; Kellogg, R.; Bearden, D.

For the last 20 years, NASA has allowed Principal Investigators (PIs) to manage the development of many unmanned space projects. Advocates of PI-led projects believe that a PI-led implementation can result in a project being developed at lower cost and shorter schedule than other implementation modes. This paper seeks to test this hypothesis by comparing the actual costs of NASA and other comparable projects developed under different implementation modes. The Aerospace Corporation's Complexity-Based Risk Assessment (CoBRA) analysis tool is used to normalize the projects such that the cost can be compared for equivalent project complexities. The data is examined both by complexity and by launch year. Cost growth will also be examined for any correlation with implementation mode. Defined in many NASA Announcements of Opportunity (AOs), a PI-led project is characterized by a central, single person with full responsibility for assembling a team and for the project's scientific integrity and the implementation and integrity of all other aspects of the mission, while operating under a cost cap. PIs have larger degrees of freedom to achieve the stated goals within NASA guidelines and oversight. This study leverages the definitions and results of previous National Research Council studies of PI-led projects. Aerospace has defined a complexity index, derived from mission performance, mass, power, and technology choices, to arrive at a broad representation of missions for purposes of comparison. Over a decade of research has established a correlation between mission complexity and spacecraft development cost and schedule. This complexity analysis, CoBRA, is applied to compare a PI-led set of New Frontiers, Discovery, Explorers, and Earth System Science Pathfinder missions to the overall NASA mission dataset. This reveals the complexity trends against development costs, cost growth, and development era.

Jupiter's Main Ring/Ring Halo

NASA Technical Reports Server (NTRS)

1997-01-01

A mosaic of four images taken through the clear filter (610 nanometers) of the solid state imaging (CCD) system aboard NASA's Galileo spacecraft on November 8, 1996, at a resolution of approximately 46 kilometers (28.5 miles) per picture element (pixel) along Jupiter's rings. Because the spacecraft was only about 0.5 degrees above the ring plane, the image is highly foreshortened in the vertical direction. The images were obtained when Galileo was in Jupiter's shadow, peering back toward the Sun; the ring was approximately 2.3 million kilometers (1.4 million miles) away. The arc on the far right of the image is produced when sunlight is scattered by small particles comprising Jupiter's upper atmospheric haze. The ring also efficiently scatters light, indicating that much of its brightness is due to particles that are microns or less in diameter. Such small particles are believed to have human-scale lifetimes, i.e., very brief compared to the solar system's age.

Jupiter's ring system is composed of three parts - - a flat main ring, a lenticular halo interior to the main ring, and the gossamer ring, outside the main ring. The near and far arms of Jupiter's main ring extend horizontally across the mosaic, joining together at the ring's ansa, on the figure's far left side. The near arm of the ring appears to be abruptly truncated close to the planet, at the point where it passes into Jupiter's shadow. Some radial structure is barely visible across the ring's ansa (top image). A faint mist of particles can be seen above and below the main rings. This vertically extended 'halo' is unusual in planetary rings, and is probably caused by electromagnetic forces pushing the smallest grains out of the ring plane. Because of shadowing, the halo is not visible close to Jupiter in the lower right part of the mosaic. To accentuate faint features in the bottom image of the ring halo, different brightnesses are shown through color. Brightest features are white or yellow and the

Jupiter - Io In Front of Jupiter Turbulent Clouds

NASA Image and Video Library

1996-11-13

This photograph of the southern hemisphere of Jupiter was obtained by Voyager 2 on June 25, 1979, at a distance of 12 million kilometers (8 million miles). The Voyager spacecraft is rapidly nearing the giant planet, with closest approach to occur at 4:23 pm PDT on July 9. Seen in front of the turbulent clouds of the planet is Io, the innermost of the large Galilean satellites of Jupiter. Io is the size of our moon. Voyager discovered in early March that Io is the most volcanically active planetary body known in the solar system, with continuous eruptions much larger than any that take place on the Earth. The red, orange, and yellow colors of Io are thought to be deposits of sulfur and sulfur compounds produced in these eruptions. The smallest features in either Jupiter or Io that can be distinguished in this picture are about 200 kilometers (125 miles) across; this resolution, it is not yet possible to identify individual volcanic eruptions. Monitoring of the erupture activity of Io by Voyager 2 will begin about July 5 and will extend past the encounter July 9. http://photojournal.jpl.nasa.gov/catalog/PIA00371

Jovian Tour Design for Orbiter and Lander Missions to Europa

NASA Technical Reports Server (NTRS)

Campagnola, Stefano; Buffington, Brent B.; Petropoulos, Anastassios E.

2013-01-01

Europa is one of the most interesting targets for solar system exploration, as its ocean of liquid water could harbor life. Following the recommendation of the Planetary Decadal Survey, NASA commissioned a study for a flyby mission, an orbiter mission, and a lander mission. This paper presents the moon tours for the lander and orbiter concepts. The total delta v and radiation dose would be reduced by exploiting multi-body dynamics and avoiding phasing loops in the Ganymede-to- Europa transfer. Tour 11-O3, 12-L1 and 12-L4 are presented in details and their performaces compared to other tours from previous Europa mission studies.

Detection of water vapor on Jupiter

NASA Technical Reports Server (NTRS)

Larson, H. P.; Fink, U.; Treffers, R.; Gautier, T. N., III

1975-01-01

High-altitude (12.4 km) spectroscopic observations of Jupiter at 5 microns from the NASA 91.5 cm airborne infrared telescope have revealed 14 absorptions assigned to the rotation-vibration spectrum of water vapor. Preliminary analysis indicates a mixing ratio about 1 millionth for the vapor phase of water. Estimates of temperature (greater than about 300 K) and pressure (less than 20 atm) suggest observation of water deep in Jupiter's hot spots responsible for its 5 micron flux. Model-atmosphere calculations based on radiative-transfer theory may change these initial estimates and provide a better physical picture of Jupiter's atmosphere below the visible cloud tops.

Juno Captures Jupiter Cloudscape in High Resolution

NASA Image and Video Library

2017-03-01

This close-up view of Jupiter captures the turbulent region just west of the Great Red Spot in the South Equatorial Belt, with resolution better than any previous pictures from Earth or other spacecraft. NASA's Juno spacecraft captured this image with its JunoCam citizen science instrument when the spacecraft was a mere 5,400 miles (8,700 kilometers) above Jupiter's cloudtops on Dec. 11, 2016 at 9:14 a.m. PT (12:14 p.m. ET). Citizen scientist Sergey Dushkin produced the sublime color processing and cropped the image to draw viewers' eyes to the dynamic clouds. http://photojournal.jpl.nasa.gov/catalog/PIA21384

Motion in Jupiter's Atmospheric Vortices (Near-infrared filters)

NASA Image and Video Library

1998-03-26

Two frame "movie" of a pair of vortices in Jupiter's southern hemisphere. The two frames are separated by ten hours. The right oval is rotating counterclockwise, like other anticyclonic bright vortices in Jupiter's atmosphere. The left vortex is a cyclonic (clockwise) vortex. The differences between them (their brightness, their symmetry, and their behavior) are clues to how Jupiter's atmosphere works. The frames span about fifteen degrees in latitude and longitude and are centered at 141 degrees west longitude and 36 degrees south planetocentric latitude. Both vortices are about 3500 kilometers in diameter in the north-south direction. The images were taken in near infrared light at 756 nanometers and show clouds that are at a pressure level of about 1 bar in Jupiter's atmosphere. North is at the top. The smallest resolved features are tens of kilometers in size. These images were taken on May 7, 1997, at a range of 1.5 million kilometers by the Solid State Imaging system on NASA's Galileo spacecraft. An animation is available at http://photojournal.jpl.nasa.gov/catalog/PIA01230

Arrival and Departure at Jupiter

NASA Image and Video Library

2016-09-02

This montage of 10 JunoCam images shows Jupiter growing and shrinking in apparent size before and after NASA's Juno spacecraft made its closest approach on August 27, 2016, at 12:50 UTC. The images are spaced about 10 hours apart, one Jupiter day, so the Great Red Spot is always in roughly the same place. The small black spots visible on the planet in some of the images are shadows of the large Galilean moons. The images in the top row were taken during the inbound leg of the orbit, beginning on August 25 at 13:15 UTC when Juno was 1.4 million miles (2.3 million kilometers) away from Jupiter, and continuing to August 27 at 04:45 UTC when the spacecraft was 430,000 miles (700,000 kilometers) away. The images in the bottom row were obtained during the outbound leg of the orbit. They begin on August 28 at 00:45 UTC when Juno was 750,000 miles (920,000 kilometers) away and continue to August 29 at 16:45 UTC when the spacecraft was 1.6 million miles (2.5 million kilometers) away. http://photojournal.jpl.nasa.gov/catalog/PIA21034

Hubble Catches Jupiter's Largest Moon Going to the 'Dark Side'

NASA Image and Video Library

2017-12-08

Hubble Catches Jupiter's Largest Moon Going to the 'Dark Side' HST/WFPC2 Image of Jupiter and Ganymede Taken April 9, 2007 NASA's Hubble Space Telescope has caught Jupiter's moon Ganymede playing a game of "peek-a-boo." In this crisp Hubble image, Ganymede is shown just before it ducks behind the giant planet. Ganymede completes an orbit around Jupiter every seven days. Because Ganymede's orbit is tilted nearly edge-on to Earth, it routinely can be seen passing in front of and disappearing behind its giant host, only to reemerge later. Composed of rock and ice, Ganymede is the largest moon in our solar system. It is even larger than the planet Mercury. But Ganymede looks like a dirty snowball next to Jupiter, the largest planet in our solar system. Jupiter is so big that only part of its Southern Hemisphere can be seen in this image. Hubble's view is so sharp that astronomers can see features on Ganymede's surface, most notably the white impact crater, Tros, and its system of rays, bright streaks of material blasted from the crater. Tros and its ray system are roughly the width of Arizona. The image also shows Jupiter's Great Red Spot, the large eye-shaped feature at upper left. A storm the size of two Earths, the Great Red Spot has been raging for more than 300 years. Hubble's sharp view of the gas giant planet also reveals the texture of the clouds in the Jovian atmosphere as well as various other storms and vortices. Astronomers use these images to study Jupiter's upper atmosphere. As Ganymede passes behind the giant planet, it reflects sunlight, which then passes through Jupiter's atmosphere. Imprinted on that light is information about the gas giant's atmosphere, which yields clues about the properties of Jupiter's high-altitude haze above the cloud tops. This color image was made from three images taken on April 9, 2007, with the Wide Field Planetary Camera 2 in red, green, and blue filters. The image shows Jupiter and Ganymede in close to natural colors. For

Time Series of Jupiter Aurora

NASA Image and Video Library

1998-06-10

These mosaics of Jupiter's night side show the Jovian aurora at approximately 45 minute intervals as the auroral ring rotated with the planet below the spacecraft. The images were obtained by the Solid State Imaging (SSI) system on NASA's Galileo spacecraft. during its eleventh orbit of Jupiter. The auroral ring is offset from Jupiter's pole of rotation and reaches the lowest latitude near 165 degrees west longitude. The aurora is hundreds of kilometers wide, and when it crosses the edge of Jupiter, it is about 250 kilometers above the planet. As on Earth, the auroral emission is caused by electrically charged particles striking atoms in the upper atmosphere from above. The particles travel along Jupiter's magnetic field lines, but their origin is not fully understood. The field lines where the aurora is most intense cross the Jovian equator at large distances (many Jovian radii) from the planet. The faint background throughout the image is scattered light in the camera. This stray light comes from the sunlit portion of Jupiter, which is out of the image. In multispectral observations the aurora appears red, consistent with how atomic hydrogen in Jupiter's atmosphere would glow. Galileo's unique perspective allows it to view the night side of the planet at short range, revealing details that cannot be seen from Earth. These detailed features are time dependent, and can be followed in this sequence of Galileo images. In the first mosaic, the auroral ring is directly over Jupiter's limb and is seen "edge on." In the fifth mosaic, the auroral emission is coming from several distinct bands. This mosaic also shows the footprint of the Io flux tube. Volcanic eruptions on Jupiter's moon, Io, spew forth particles that become ionized and are pulled into Jupiter's magnetic field to form an invisible tube, the Io flux tube, between Jupiter and Io. The bright circular feature towards the lower right may mark the location where these energetic particles impact Jupiter. Stars

Juno Captures Jupiter Glow in Infrared Light

NASA Image and Video Library

2016-09-02

As NASA's Juno spacecraft approached Jupiter on Aug. 27, 2016, the Jovian Infrared Auroral Mapper (JIRAM) instrument captured the planet's glow in infrared light. The video is composed of 580 images collected over a period of about nine hours while Jupiter completed nearly a full rotation on its axis. The video shows the two parts composing the JIRAM imager: the lower one, in a red color scale, is used for mapping the planet's thermal emission at wavelengths around 4.8 microns; the upper one, in a blue color scale, is used to map the auroras at wavelengths around 3.45 microns. In this case the exposure time of the imager was optimized to observe the planet's thermal emission. However, it is possible to see a faint aurora and Jupiter's moon Io approaching the planet. The Great Red Spot is also visible just south of the planet's equator. A movie is available at http://photojournal.jpl.nasa.gov/catalog/PIA21036

Jupiter's Stunning Southern Hemisphere

NASA Image and Video Library

2017-11-09

See Jupiter's southern hemisphere in beautiful detail in this new image taken by NASA's Juno spacecraft. The color-enhanced view captures one of the white ovals in the "String of Pearls," one of eight massive rotating storms at 40 degrees south latitude on the gas giant planet. The image was taken on Oct. 24, 2017 at 11:11 a.m. PDT (2:11 p.m. EDT), as Juno performed its ninth close flyby of Jupiter. At the time the image was taken, the spacecraft was 20,577 miles (33,115 kilometers) from the tops of the clouds of the planet at a latitude of minus 52.96 degrees. The spatial scale in this image is 13.86 miles/pixel (22.3 kilometers/pixel). Citizen scientists Gerald Eichstädt and Seán Doran processed this image using data from the JunoCam imager. https://photojournal.jpl.nasa.gov/catalog/PIA21970

Juno Captures the Roar of Jupiter

NASA Image and Video Library

2016-06-30

NASA's Juno spacecraft has crossed into Jupiter's immense magnetic field. Juno's Waves instrument recorded the crossing of the bow shock on June 24, 2016, represented by the following animation and sound.

Jupiter's Great Red Spot, Spotted

NASA Image and Video Library

2018-04-19

This image of Jupiter's iconic Great Red Spot and surrounding turbulent zones was captured by NASA's Juno spacecraft. The color-enhanced image is a combination of three separate images taken on April 1 between 3:09 a.m. PDT (6:09 a.m. EDT) and 3:24 a.m. PDT (6:24 a.m. EDT), as Juno performed its 12th close flyby of Jupiter. At the time the images were taken, the spacecraft was 15,379 miles (24,749 kilometers) to 30,633 miles (49,299 kilometers) from the tops of the clouds of the planet at a southern latitude spanning 43.2 to 62.1 degrees. Citizen scientists Gerald Eichstädt and Seán Doran processed this image using data from the JunoCam imager. https://photojournal.jpl.nasa.gov/catalog/PIA21985

Jupiter's Clouds of Many Colors

NASA Image and Video Library

2017-06-15

NASA's Juno spacecraft was racing away from Jupiter following its seventh close pass of the planet when JunoCam snapped this image on May 19, 2017, from about 29,100 miles (46,900 kilometers) above the cloud tops. The spacecraft was over 65.9 degrees south latitude, with a lovely view of the south polar region of the planet. This image was processed to enhance color differences, showing the amazing variety in Jupiter's stormy atmosphere. The result is a surreal world of vibrant color, clarity and contrast. Four of the white oval storms known as the "String of Pearls" are visible near the top of the image. Interestingly, one orange-colored storm can be seen at the belt-zone boundary, while other storms are more of a cream color. https://photojournal.jpl.nasa.gov/catalog/PIA21392

Improvement of Europa's Gravity and Body Tides and Shape with a Laser Altimeter during a Flyby Tour

NASA Astrophysics Data System (ADS)

Mazarico, E.; Genova, A.; Smith, D. E.; Zuber, M. T.

2014-12-01

Laser altimeters have been primarily utilized with orbiter spacecraft. Recently, the Mercury Laser Altimeter on MESSENGER successfully operated at Mercury during two flybys and thousands of highly-elliptical orbits, and contributed greatly towards improved understanding of the innermost planet. We show that a laser altimeter instrument on a flyby tour mission such as the planned NASA Europa Clipper can constrain key geophysical parameters when supported by variable-frequency altimetric measurements over repeated ~145°-long arcs across the surface. Previous work by Park et al. (2011, GRL) showed through covariance analysis that a similar trajectory could yield the gravity tidal Love number k2 to good accuracy (0.05). Here, we conduct a full simulation of a 45-flyby trajectory in the Jupiter system with Europa as primary target. We consider reasonable tracking coverage and noise level (dominated by plasma noise), as well as gravity (degree 50) and topography (200m resolution supplemented by realistic fractal noise at shorter wavelengths), informed by relevant existing data (Galileo, Cassini). The simulation is initialized at pessimistic values, with C20, C22, k2, and h2 in error of 90%, 90%, 50%, and 50%, respectively. All other gravity coefficients up to degree 3 have zero a priori values. Assumed altimetric data sampling and noise are derived from the tour trajectory and the instrument performance described by Smith et al. (this meeting). This variable-frequency laser altimeter can greatly improve the surface coverage (for shape recovery) and the number of altimetric crossovers, the best measurement type to constrain the tidal surface deformation. We find from our simulation that the addition of altimetry data significantly improves the determination of the gravity tidal Love number k2 and enables the recovery of the body tidal Love number h2. Low-degree gravity and topography are most important to constrain the interior structure of Europa. Scientific objectives

Ganymede: A Window into the Evolution of the Jupiter System (Invited)

NASA Astrophysics Data System (ADS)

Collins, G. C.

2009-12-01

processes. How is Ganymede’s field generated, and how long has it persisted? 5) Ganymede also appears to have an induced magnetic field, which is evidence for a subsurface ocean. Confirmation of the existence of this ocean and its size are important science goals at Ganymede. How has the ocean varied over time, and what is the composition and biological potential of the ocean? 6) The boundary between open and closed magnetic field lines intersecting Ganymede’s surface is clearly visible in color images, showing the effect of different space weathering conditions on the same starting material. How does the magnetic field shield the surface from radiolytic processes, and how can this help us understand processes on the surfaces of unshielded Galilean satellites? 7) Ganymede’s surface is mostly water ice, with evidence for Europa-like hydrated salts and Callisto-like tholins and silicate dust. How variable is the composition of the ice shell? How is the distribution of various non-ice materials related to the surface geology? The Europa Jupiter System Mission currently being planned by NASA and ESA includes a Jupiter Ganymede Orbiter element that would provide us with much of the necessary data to answer the outstanding science questions above. (Acknowledgements to my coauthors on the Decadal Survey Community White Paper on Ganymede science questions)

Still from High-Clouds Jupiter Movie

NASA Technical Reports Server (NTRS)

2000-01-01

This image is one of seven from the narrow-angle camera on NASA's Cassini spacecraft assembled as a brief movie of high-altitude cloud movements on Jupiter. It was taken in early October 2000.

The images were taken at a wavelength that is absorbed by methane, one chemical in Jupiter's lower clouds. So, dark areas are relatively free of high clouds, and the camera sees through to the methane in a lower level. Bright areas are places with high, thick clouds that shield the methane below.

The area shown covers latitudes from 50 degrees north to 50 degrees south and a 100-degree sweep of longitude.

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.

Himalia, a Small Moon of Jupiter

NASA Technical Reports Server (NTRS)

2001-01-01

NASA's Cassini spacecraft captured images of Himalia, the brightest of Jupiter's outer moons, on Dec. 19, 2000, from a distance of 4.4 million kilometers (2.7 million miles).

This near-infrared image, with a resolution of about 27 kilometers (17 miles) per pixel, indicates that the side of Himalia facing the spacecraft is roughly 160 kilometers (100 miles) in the up-down direction. Himalia probably has a non-spherical shape. Scientists believe it is a body captured into orbit around Jupiter, most likely an irregularly shaped asteroid.

In the main frame, an arrow indicates Himalia. North is up. The inset shows the little moon magnified by a factor of 10, plus a graphic indicating Himalia's size and the direction of lighting (with sunlight coming from the left). Cassini's pictures of Himalia were taken during a brief period when Cassini's attitude was stabilized by thrusters instead of by a steadier reaction-wheel system. No spacecraft or telescope had previously shown any of Jupiter's outer moons as more than a star-like single dot.

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.

Collision of comet Shoemaker-Levy 9 with Jupiter observed by the NASA infrared telescope facility

NASA Technical Reports Server (NTRS)

Orton, G.; A'Hearn, M.; Baines, K.; Deming, D.; Dowling, T.; Goguen, J.; Griffith, C.; Hammel, H.; Hoffmann, W.; Hunten, D.;

Collision of comet Shoemaker-Levy 9 with Jupiter observed by the NASA infrared telescope facility.

PubMed

Orton, G; A'Hearn, M; Baines, K; Deming, D; Dowling, T; Goguen, J; Griffith, C; Hammel, H; Hoffmann, W; Hunten, D

1995-03-03

The National Aeronautics and Space Administration (NASA) Infrared Telescope Facility was used to investigate the collision of comet Shoemaker-Levy 9 with Jupiter from 12 July to 7 August 1994. Strong thermal infrared emission lasting several minutes was observed after the impacts of fragments C, G, and R. All impacts warmed the stratosphere and some the troposphere up to several degrees. The abundance of stratospheric ammonia increased by more than 50 times. Impact-related particles extended up to a level where the atmospheric pressure measured several millibars. The north polar near-infrared aurora brightened by nearly a factor of 5 a week after the impacts.

Peering Deep into Jupiter Atmosphere

NASA Image and Video Library

2013-03-14

The dark hot spot in this false-color image from NASA Cassini spacecraft is a window deep into Jupiter atmosphere. All around it are layers of higher clouds, with colors indicating which layer of the atmosphere the clouds are in.

Commentary: The Feasibility of Subduction and Implications for Plate Tectonics on Jupiter's Moon Europa

NASA Astrophysics Data System (ADS)

Kattenhorn, Simon A.

2018-03-01

A new modeling-based study by Johnson et al. (2017, https://doi.org/10.1002/2017JE005370) lends support to the hypothesis that portions of Europa's surface may have been removed by the process of subduction, as suggested by Kattenhorn and Prockter (2014, https://doi.org/10.1038/NGEO2245). Using a simple 1-D model that tracks the thermal and density structure of a descending ice plate, Johnson et al. show that ice plates with 10% porosity and overall salt contents of 5%, which differ in salt content by 2.5% from the surrounding reference ice shell, are nonbuoyant and thus likely to sink through the underlying, convecting portion of the ice shell. The feasibility of subduction in an ice shell is critical to the existence of icy plate tectonics, which is hypothesized to exist at least locally on Europa, potentially making it the only other Solar System body other than Earth with a surface modified by plate tectonics.

Fractures on Europa - Possible response of an ice crust to tidal deformation

NASA Technical Reports Server (NTRS)

Helfenstein, P.; Parmentier, E. M.

1980-01-01

The surface of Europa contains a planetwide system of low albedo lineaments which have been interpreted as fractures in an icy crust. The pattern of fractures on the surface consists of radial and concentric fractures having the general appearance of tension cracks within a region near the antipode of the sub-Jupiter point. Outside this region, linear fractures intersect at angles near 60 deg, suggesting that they are conjugate shear fractures. The orientation of this pattern on the surface suggests that a principal axis of the deformation that produced the fractures was approximately radial to Jupiter. Fracturing may thus be consistent with an origin due to cyclical tidal deformation resulting from orbital eccentricity. Orbital eccentricity related to a relatively recent establishment of orbital resonance among the Galilean satellites may explain the presence of fractures in a relatively young, lightly cratered planetary surface.

Origin, Bulk Chemical Composition and Physical Structure of the Galilean Satellites of Jupiter: A Post-Galileo Analysis

NASA Technical Reports Server (NTRS)

Prentice, A. J. R.

1999-01-01

The origin of Jupiter and the Galilean satellite system is examined in the light of the new data that has been obtained by the NASA Galileo Project. In particular, special attention is given to a theory of satellite origin which was put forward at the start of the Galileo Mission and on the basis of which several predictions have now been proven successful. These predictions concern the chemical composition of Jupiter's atmosphere and the physical structure of the satellites. According to the proposed theory of satellite origin, each of the Galilean satellites formed by chemical condensation and gravitational accumulation of solid grains within a concentric family of orbiting gas rings. These rings were cast off equatorially by the rotating proto-Jovian cloud (PJC which contracted gravitationally to form Jupiter some 4 1/2 billion years ago. The PJC formed from the gas and grains left over from the gas ring that had been shed at Jupiter's orbit by the contracting proto-solar cloud (PSC Supersonic turbulent convection provides the means for shedding discrete gas rings. The temperatures T (sub n) of the system of gas rings shed by the PSC and PJC vary with their respective mean orbital radii R (sub n) (n = 0, 1,2,...) according as T (sub n) proportional to R (sub n) (exp -0.9). If the planet Mercury condenses at 1640 K, so accounting for the high density of that planet via a process of chemical fractionation between iron and silicates, then T (sub n) at Jupiter's orbit is 158 K. Only 35% of the water vapour condenses out. Thus fractionation between rock and ice, together with an enhancement in the abundance of solids relative to gas which takes place through gravitational sedimentation of solids onto the mean orbit of the gas ring, ensures nearly equal proportions of rock and ice in each of Ganymede and Callisto. Io and Europa condense above the H20 ice point and consist solely of hydrated rock (h-rock). The Ganymedan condensate consists of h-rock and H20 ice. For

Secondary craters on Europa and implications for cratered surfaces.

PubMed

Bierhaus, Edward B; Chapman, Clark R; Merline, William J

2005-10-20

For several decades, most planetary researchers have regarded the impact crater populations on solid-surfaced planets and smaller bodies as predominantly reflecting the direct ('primary') impacts of asteroids and comets. Estimates of the relative and absolute ages of geological units on these objects have been based on this assumption. Here we present an analysis of the comparatively sparse crater population on Jupiter's icy moon Europa and suggest that this assumption is incorrect for small craters. We find that 'secondaries' (craters formed by material ejected from large primary impact craters) comprise about 95 per cent of the small craters (diameters less than 1 km) on Europa. We therefore conclude that large primary impacts into a solid surface (for example, ice or rock) produce far more secondaries than previously believed, implying that the small crater populations on the Moon, Mars and other large bodies must be dominated by secondaries. Moreover, our results indicate that there have been few small comets (less than 100 m diameter) passing through the jovian system in recent times, consistent with dynamical simulations.

Jupiter's Auroras Acceleration Processes

NASA Image and Video Library

2017-09-06

This image, created with data from Juno's Ultraviolet Imaging Spectrometer (UVS), marks the path of Juno's readings of Jupiter's auroras, highlighting the electron measurements that show the discovery of the so-called discrete auroral acceleration processes indicated by the "inverted Vs" in the lower panel (Figure 1). This signature points to powerful magnetic-field-aligned electric potentials that accelerate electrons toward the atmosphere to energies that are far greater than what drive the most intense aurora at Earth. Scientists are looking into why the same processes are not the main factor in Jupiter's most powerful auroras. https://photojournal.jpl.nasa.gov/catalog/PIA21937

Closing in on Jupiter

NASA Image and Video Library

2016-06-16

On June 16, NASA discussed the status of its Juno mission to Jupiter during a news briefing at the agency’s headquarters, in Washington DC. This Fourth of July, the solar-powered Juno spacecraft will arrive at our solar system’s most massive planet after an almost five-year journey. Once in Jupiter’s orbit, the spacecraft will circle the Jovian world 37 times during 20 months, skimming to within 3,100 miles (5,000 kilometers) above the cloud tops. This is the first time a spacecraft will orbit the poles of Jupiter, providing new answers to ongoing mysteries about the planet’s core, composition and magnetic fields.

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.

Jupiter Great Red Spot

NASA Image and Video Library

1998-12-05

This view of Jupiter was taken by Voyager 1. This image was taken through color filters and recombined to produce the color image. This photo was assembled from three black and white negatives by the Image Processing Lab at Jet Propulsion Laboratory. http://photojournal.jpl.nasa.gov/catalog/PIA01384

Mariner Jupiter/Saturn 1977 preliminary mission design.

NASA Technical Reports Server (NTRS)

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

1972-01-01

Current plans of NASA are to take advantage of the 1977 launch opportunity by sending a Mariner class spacecraft on a gravity assisted flyby of Jupiter which will then continue on to Saturn. The background of this Mariner Jupiter-Saturn 77 Project is reviewed and science objectives for this mission as currently adapted are given. This paper illustrates properties of the Jupiter-Saturn opportunities between 1976 and 1980 to give context to the 1977 opportunity. Details of the possibilities for the 1977 launch are shown along with constraints and example candidate trajectories. Options include close flybys and/or occultations of the satellites at Jupiter and Saturn, penetration of Saturn's rings, and various occultations of the planets. A short discussion of other factors, such as navigation and planetary quarantine (documented elsewhere) are included.

Mesoscale Waves in Jupiter Atmosphere

NASA Image and Video Library

1997-09-07

These two images of Jupiter atmosphere were taken with the violet filter of the Solid State Imaging CCD system aboard NASA Galileo spacecraft. Mesoscale waves can be seen in the center of the upper image. The images were obtained on June 26, 1996.

Tides and tidal stress: Applications to Europa

NASA Astrophysics Data System (ADS)

Hurford, Terry Anthony, Jr.

A review of analytical techniques and documentation of previously inaccessible mathematical formulations is applied to study of Jupiter's satellite Europa. Compared with numerical codes that are commonly used to model global tidal effects, analytical models of tidal deformation give deeper insight into the mechanics of tides, and can better reveal the nature of the dependence of observable effects on key parameters. I develop analytical models for tidal deformation of multi-layered bodies. Previous studies of Europa, based on numerical computation, only to show isolated examples from parameter space. My results show a systematic dependence of tidal response on the thicknesses and material parameters of Europa's core, rocky mantle, liquid water ocean, and outer layer of ice. As in the earlier work, I restrict these studies to incompressible materials. Any set of Love numbers h 2 and k 2 which describe a planet's tidal deformation, could be fit by a range of ice thickness values, by adjusting other parameters such as mantle rigidity or core size, an important result for mission planning. Inclusion of compression into multilayer models has been addressed analytically, uncovering several issues that are not explicit in the literature. Full evaluation with compression is here restricted to a uniform sphere. A set of singularities in the classical solution, which correspond to instabilities due to self-gravity has been identified and mapped in parameter space. The analytical models of tidal response yield the stresses anywhere within the body, including on its surface. Crack patterns (such as cycloids) on Europa are probably controlled by these stresses. However, in contrast to previous studies which used a thin shell approximation of the tidal stress, I consider how other tidal models compare with the observed tectonic features. In this way the relationship between Europa's surface tectonics and the global tidal distortion can be constrained. While large-scale tidal

Energy for biologic sulfate reduction in a hydrothermally formed ocean on Europa

NASA Astrophysics Data System (ADS)

Zolotov, Mikhail Y.; Shock, Everett L.

2003-04-01

Formation of a sulfate-bearing ocean on Jupiter's satellite Europa by quenched hydrothermal fluids provides a source of metabolic energy for low-temperature sulfate-reducing organisms that use dissolved H2 as an electron donor. Inhibition of thermodynamically favorable sulfate reduction in cooled hydrothermal fluids creates the potential for biologic reduction. Both high temperature and reduced conditions of ocean-forming hydrothermal solutions favor sulfate reduction in quenched fluids. The maximum amount of energy available to support autotrophic sulfate reduction is on the order of a few kilojoules per kilogram of water and is limited by the low abundances of either H2 or sulfate in ocean-forming fluids. Although this irreplaceable energy source might have supported early life on Europa, maintenance of biologic sulfate reduction throughout the ocean's history would require a supply of organic compounds from endogenic sources or from the satellite's surface.

Orbit Determination Covariance Analysis for the Europa Clipper Mission

NASA Technical Reports Server (NTRS)

Ionasescu, Rodica; Martin-Mur, Tomas; Valerino, Powtawche; Criddle, Kevin; Buffington, Brent; McElrath, Timothy

2014-01-01

A new Jovian satellite tour is proposed by NASA, which would include numerous flybys of the moon Europa, and would explore its potential habitability by characterizing the existence of any water within and beneath Europa's ice shell. This paper describes the results of a covariance study that was undertaken on a sample tour to assess the navigational challenges and capabilities of such a mission from an orbit determination (OD) point of view, and to help establish a delta V budget for the maneuvers needed to keep the spacecraft on the reference trajectory. Additional parametric variations from the baseline case were also investigated. The success of the Europa Clipper mission will depend on the science measurements that it will enable. Meeting the requirements of the instruments onboard the spacecraft is an integral part of this analysis.

JUICE: A European Mission to Jupiter and its Icy Moons

NASA Astrophysics Data System (ADS)

Grasset, Olivier; Witasse, Olivier; Barabash, Stas; Brandt, Pontus; Bruzzone, Lorenzo; Bunce, Emma; Cecconi, Baptiste; Cavalié, Thibault; Cimo, Giuseppe; Coustenis, Athena; Cremonese, Gabriele; Dougherty, Michele; Fletcher, Leigh N.; Gladstone, Randy; Gurvits, Leonid; Hartogh, Paul; Hoffmann, Holger; Hussmann, Hauke; Iess, Luciano; Jaumann, Ralf; Kasaba, Yasumasa; Kaspi, Yohai; Krupp, Norbert; Langevin, Yves; Mueller-Wodarg, Ingo; Palumbo, Pasquale; Piccioni, Giuseppe; Plaut, Jeffrey; Poulet, Francois; Roatsch, Thomas; Retherford, Kurt D.; Rothkaehl, Hanna; Stevenson, David J.; Tosi, Federico; Van Hoolst, Tim; Wahlund, Jan-Erik; Wurz, Peter; Altobelli, Nicolas; Accomazzo, A.; Boutonnet, Arnaud; Erd, Christian; Vallat, Claire

2016-10-01

JUICE - JUpiter ICy moons Explorer - is the first large mission in the ESA Cosmic Vision programme [1]. The implementation phase started in July 2015. JUICE will arrive at Jupiter in October 2029, and will spend 3 years characterizing the Jovian system, the planet itself, its giant magnetosphere, and the giant icy moons: Ganymede, Callisto and Europa. JUICE will then orbit Ganymede.The first goal of JUICE is to explore the habitable zone around Jupiter [2]. Ganymede is a high-priority target because it provides a unique laboratory for analyzing the nature, evolution and habitability of icy worlds, including the characteristics of subsurface oceans, and because it possesses unique magnetic fields and plasma interactions with the environment. On Europa, the focus will be on recently active zones, where the composition, surface and subsurface features (including putative water reservoirs) will be characterized. Callisto will be explored as a witness of the early Solar System.JUICE will also explore the Jupiter system as an archetype of gas giants. The circulation, meteorology, chemistry and structure of the Jovian atmosphere will be studied from the cloud tops to the thermosphere and ionosphere. JUICE will investigate the 3D properties of the magnetodisc, and study the coupling processes within the magnetosphere, ionosphere and thermosphere. The mission also focuses on characterizing the processes that influence surface and space environments of the moons.The payload consists of 10 instruments plus a ground-based experiment (PRIDE) to better constrain the S/C position. A remote sensing package includes imaging (JANUS) and spectral-imaging capabilities from UV to sub-mm wavelengths (UVS, MAJIS, SWI). A geophysical package consists of a laser altimeter (GALA) and a radar sounder (RIME) for exploring the moons, and a radio science experiment (3GM) to probe the atmospheres and to determine the gravity fields. The in situ package comprises a suite to study plasma and

Jupiter Eruptions Captured in Infrared

NASA Technical Reports Server (NTRS)

2008-01-01

[figure removed for brevity, see original site] Click on the image for high resolution image of Nature Cover

Detailed analysis of two continent-sized storms that erupted in Jupiter's atmosphere in March 2007 shows that Jupiter's internal heat plays a significant role in generating atmospheric disturbances. Understanding these outbreaks could be the key to unlock the mysteries buried in the deep Jovian atmosphere, say astronomers.

This infrared image shows two bright plume eruptions obtained by the NASA Infrared Telescope Facility on April 5, 2007.

Understanding these phenomena is important for Earth's meteorology where storms are present everywhere and jet streams dominate the atmospheric circulation. Jupiter is a natural laboratory where atmospheric scientists study the nature and interplay of the intense jets and severe atmospheric phenomena.

According to the analysis, the bright plumes were storm systems triggered in Jupiter's deep water clouds that moved upward in the atmosphere vigorously and injected a fresh mixture of ammonia ice and water about 20 miles (30 kilometers) above the visible clouds. The storms moved in the peak of a jet stream in Jupiter's atmosphere at 375 miles per hour (600 kilometers per hour). Models of the disturbance indicate that the jet stream extends deep in the buried atmosphere of Jupiter, more than 60 miles (approximately100 kilometers) below the cloud tops where most sunlight is absorbed.

Jupiter's Northern Hemisphere in True Color (Time Set 2)

NASA Technical Reports Server (NTRS)

1997-01-01

Mosaic of Jupiter's northern hemisphere between 10 and 50 degrees latitude. Jupiter's atmospheric circulation is dominated by alternating eastward and westward jets from equatorial to polar latitudes. The direction and speed of these jets in part determine the color and texture of the clouds seen in this mosaic. Also visible are several other common Jovian cloud features, including large white ovals, bright spots, dark spots, interacting vortices, and turbulent chaotic systems. The north-south dimension of each of the two interacting vortices in the upper half of the mosaic is about 3500 kilometers. This mosaic combines the violet (410 nanometers) and near infrared continuum (756 nanometers) filter images to create a mosaic similar to how Jupiter would appear to human eyes. Differences in coloration are due to the composition and abundance of trace chemicals in Jupiter's atmosphere.

North is at the top. The images are projected on a sphere, with features being foreshortened towards the north. The smallest resolved features are tens of kilometers in size. These images were taken on April 3, 1997, at a range of 1.4 million kilometers by the Solid State Imaging system (CCD) on NASA's Galileo spacecraft.

The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.

This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

Surfing Jupiter

NASA Image and Video Library

2017-05-25

Waves of clouds at 37.8 degrees latitude dominate this three-dimensional Jovian cloudscape, courtesy of NASA's Juno spacecraft. JunoCam obtained this enhanced-color picture on May 19, 2017, at 5:50 UTC from an altitude of 5,500 miles (8,900 kilometers). Details as small as 4 miles (6 kilometers) across can be identified in this image. The small bright high clouds are about 16 miles (25 kilometers) across and in some areas appear to form "squall lines" (a narrow band of high winds and storms associated with a cold front). On Jupiter, clouds this high are almost certainly composed of water and/or ammonia ice. https://photojournal.jpl.nasa.gov/catalog/PIA21646

Tectonics of Europa

NASA Astrophysics Data System (ADS)

Kattenhorn, S. A.; Hurford, T. A.

2007-12-01

This review of Europan tectonics previews a chapter of the forthcoming text "Europa". After the Voyager flyby of the icy moon Europa in 1979, models were developed that attributed pervasive surface fracturing to the effects of tidal forcing due to the gravitational pull of Jupiter. The late 1990s Galileo mission returned high resolution coverage of the surface, allowing a diverse range of tectonic features to be identified. Subsequent description, interpretation, and modeling of these features has resulted in significant developments in five key themes: (1) What drives the tectonics? (2) What are the formation mechanisms of the various types of tectonic features? (3) What are the implications for a subsurface ocean? (4) What is the nature and thickness of the ice shell? (5) Is Europa currently tectonically active? We highlight key developments pertaining to these fundamental issues, focusing on the following elements: (1) Many fracture patterns can be correlated with theoretical stress fields induced by diurnal tidal forcing and long-term effects of nonsynchronous rotation of the ice shell; however, these driving mechanisms alone cannot explain all fracturing. The tectonic fabric has likely been affected by additional contributing effects: tidal despinning, orbital evolution, interior differentiation, polar wander, finite obliquity, stresses due to shell thickening, endogenic forcing by convection and diapirism, and secondary effects driven by strike-slip faulting and plate flexure. (2) Due to the prevalence of global tension, a low lithostatic gradient, and the inherent weakness of ice, tectonic features likely have predominantly extensional primary formation mechanisms (e.g. surface fractures, ridges, and normal faults). There has been no categorical documentation of fracture development by compressive shearing. Even so, the constantly changing nature of the tidal stress field results in shearing reactivation of cracks being important for the morphologic and

Jupiter Fractal Art

NASA Image and Video Library

2017-08-10

See Jupiter's Great Red Spot as you've never seen it before in this new Jovian work of art. Artist Mik Petter created this unique, digital artwork using data from the JunoCam imager on NASA's Juno spacecraft. The art form, known as fractals, uses mathematical formulas to create art with an infinite variety of form, detail, color and light. The tumultuous atmospheric zones in and around the Great Red Spot are highlighted by the author's use of colorful fractals. Vibrant colors of various tints and hues, combined with the almost organic-seeming shapes, make this image seem to be a colorized and crowded petri dish of microorganisms, or a close-up view of microscopic and wildly-painted seashells. The original JunoCam image was taken on July 10, 2017 at 7:10 p.m. PDT (10:10 p.m. EDT), as the Juno spacecraft performed its seventh close flyby of Jupiter. The spacecraft captured the image from about 8,648 miles (13,917 kilometers) above the tops of the clouds of the planet at a latitude of -32.6 degrees. https://photojournal.jpl.nasa.gov/catalog/PIA21777

Dark and Stormy Jupiter

NASA Image and Video Library

2018-06-14

This image captures the intensity of the jets and vortices in Jupiter's North North Temperate Belt. NASA's Juno spacecraft took this color-enhanced image at 10:31 p.m. PDT on May 23, 2018 (1:31 a.m. EDT on May 24), as Juno performed its 13th close flyby of Jupiter. At the time, the spacecraft was about 4,900 miles (7,900 kilometers) from the tops of the clouds of the gas giant planet at a northern latitude of about 41 degrees. The view is oriented with south on Jupiter toward upper left and north toward lower right. The North North Temperate Belt is the prominent reddish-orange band left of center. It rotates in the same direction as the planet and is predominantly cyclonic, which in the northern hemisphere means its features spin in a counter-clockwise direction. Within the belt are two gray-colored anticyclones. To the left of the belt is a brighter band (the North North Temperate Zone) with high clouds whose vertical relief is accentuated by the low angle of sunlight near the terminator. These clouds are likely made of ammonia-ice crystals, or possibly a combination of ammonia ice and water. Although the region as a whole appears chaotic, there is an alternating pattern of rotating, lighter-colored features on the zone's north and south sides. Scientists think the large-scale dark regions are places where the clouds are deeper, based on infrared observations made at the same time by Juno's JIRAM experiment and Earth-based supporting observations. Those observations show warmer, and thus deeper, thermal emission from these regions. To the right of the bright zone, and farther north on the planet, Jupiter's striking banded structure becomes less evident and a region of individual cyclones can be seen, interspersed with smaller, darker anticyclones. https://photojournal.jpl.nasa.gov/catalog/PIA22423

Jupiter: A New Point of View

NASA Image and Video Library

2017-08-16

This striking Jovian vista was created by citizen scientists Gerald Eichstädt and Seán Doran using data from the JunoCam imager on NASA's Juno spacecraft. The tumultuous Great Red Spot is fading from Juno's view while the dynamic bands of the southern region of Jupiter come into focus. North is to the left of the image, and south is on the right. The image was taken on July 10, 2017 at 7:12 p.m. PDT (10:12 p.m. EDT), as the Juno spacecraft performed its seventh close flyby of Jupiter. At the time the image was taken, the spacecraft was 10,274 miles (16,535 kilometers) from the tops of the clouds of the planet at a latitude of -36.9 degrees. https://photojournal.jpl.nasa.gov/catalog/PIA21778

Prospects of passive radio detection of a subsurface ocean on Europa with a lander

NASA Astrophysics Data System (ADS)

Romero-Wolf, Andrew; Schroeder, Dustin M.; Ries, Paul; Bills, Bruce G.; Naudet, Charles; Scott, Bryan R.; Treuhaft, Robert; Vance, Steve

2016-09-01

We estimate the sensitivity of a lander-based instrument for the passive radio detection of a subsurface ocean beneath the ice shell of Europa, expected to be between 3 km and 30 km thick, using Jupiter's decametric radiation. A passive technique was previously studied for an orbiter. Using passive detection in a lander platform provides a point measurement with significant improvements due to largely reduced losses from surface roughness effects, longer integration times, and diminished dispersion due to ionospheric effects allowing operation at lower frequencies and a wider band. A passive sounder on-board a lander provides a low resource instrument sensitive to subsurface ocean at Europa up to depths of 6.9 km for high loss ice (16 dB/km two-way attenuation rate) and 69 km for pure ice (1.6 dB/km).

The influence of meridional ice transport on Europa's ocean stratification and heat content

NASA Astrophysics Data System (ADS)

Zhu, Peiyun; Manucharyan, Georgy E.; Thompson, Andrew F.; Goodman, Jason C.; Vance, Steven D.

2017-06-01

Jupiter's moon Europa likely hosts a saltwater ocean beneath its icy surface. Geothermal heating and rotating convection in the ocean may drive a global overturning circulation that redistributes heat vertically and meridionally, preferentially warming the ice shell at the equator. Here we assess the previously unconstrained influence of ocean-ice coupling on Europa's ocean stratification and heat transport. We demonstrate that a relatively fresh layer can form at the ice-ocean interface due to a meridional ice transport forced by the differential ice shell heating between the equator and the poles. We provide analytical and numerical solutions for the layer's characteristics, highlighting their sensitivity to critical ocean parameters. For a weakly turbulent and highly saline ocean, a strong buoyancy gradient at the base of the freshwater layer can suppress vertical tracer exchange with the deeper ocean. As a result, the freshwater layer permits relatively warm deep ocean temperatures.

The influence of meridional ice transport on Europa's ocean stratification and heat content

NASA Astrophysics Data System (ADS)

Zhu, P.; Manucharyan, G.; Thompson, A. F.; Goodman, J. C.; Vance, S.

2017-12-01

Jupiter's moon Europa likely hosts a saltwater ocean beneath its icy surface. Geothermal heating and rotating convection in the ocean may drive a global overturning circulation that redistributes heat vertically and meridionally, preferentially warming the ice shell at the equator. Here we assess thepreviously unconstrained influence of ocean-ice coupling on Europa's ocean stratification and heat transport. We demonstrate that a relatively fresh layer can form at the ice-ocean interface due to a meridional ice transport forced by the differential ice shell heating between the equator and the poles. We provide analytical and numerical solutions for the layer's characteristics, highlighting their sensitivity to critical ocean parameters. For a weakly turbulent and highly saline ocean, a strong buoyancy gradient at the base of the freshwater layer can suppress vertical tracer exchange with the deeper ocean. As a result, the freshwater layer permits relatively warm deep ocean temperatures.

Europa: Processes and Habitability

NASA Technical Reports Server (NTRS)

Pappalardo, Robert T.

2006-01-01

This viewgraph presentation reviews the known and possible geologic processes of Europa. It shows slides of Europa, with different terrains (ridged plains and molten plains), and a possible view of the interior. Europa's eccentric orbit is reviewed. The presentation also reviews Europa's composition. The possible reasons for Europa's geology are reviewed. Also the possiblity that life exists on Europa is raised. The planned Europa Geophysical Explorer mission is also reviewed.

Sulfate content of Europa's ocean and shell: evolutionary considerations and some geological and astrobiological implications.

PubMed

McKinnon, William B; Zolensky, Michael E

2003-01-01

Recent models for the origin of Jupiter indicate that the Galilean satellites were mostly derived from largely unprocessed solar nebula solids and planetesimals. In the jovian subnebula the solids that built Europa were first heated and then cooled, but the major effect was most likely partial or total devolatilization, and less likely to have been wholesale thermochemical reprocessing of rock + metal compositions (e.g., oxidation of Fe and hydration of silicates). Ocean formation and substantial alteration of interior rock by accreted water and ice would occur during and after accretion, but none of the formation models predicts or implies accretion of sulfates. Europa's primordial ocean was most likely sulfidic. After accretion and later radiogenic and tidal heating, the primordial ocean would have interacted hydrothermally with subjacent rock. It has been hypothesized that sulfides could be converted to sulfates if sufficient hydrogen was lost to space, but pressure effects and the impermeability of serpentinite imply that extraction of sulfate from thoroughly altered Europa-rock would have been inefficient (if indeed Mg sulfates formed at all). Permissive physical limits on the extent of alteration limit the sulfate concentration of Europa's evolved ocean to 10% by weight MgSO(4) or equivalent. Later oxidation of the deep interior of Europa may have also occurred because of water released by the breakdown of hydrated silicates, ultimately yielding S magma and/or SO(2) gas. Geological and astrobiological implications are considered.

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

NASA reports

NASA Technical Reports Server (NTRS)

Obrien, John E.; Fisk, Lennard A.; Aldrich, Arnold A.; Utsman, Thomas E.; Griffin, Michael D.; Cohen, Aaron

1992-01-01

Activities and National Aeronautics and Space Administration (NASA) programs, both ongoing and planned, are described by NASA administrative personnel from the offices of Space Science and Applications, Space Systems Development, Space Flight, Exploration, and from the Johnson Space Center. NASA's multi-year strategic plan, called Vision 21, is also discussed. It proposes to use the unique perspective of space to better understand Earth. Among the NASA programs mentioned are the Magellan to Venus and Galileo to Jupiter spacecraft, the Cosmic Background Explorer, Pegsat (the first Pegasus payload), Hubble, the Joint U.S./German ROSAT X-ray Mission, Ulysses to Jupiter and over the sun, the Astro-Spacelab Mission, and the Gamma Ray Observatory. Copies of viewgraphs that illustrate some of these missions, and others, are provided. Also discussed were life science research plans, economic factors as they relate to space missions, and the outlook for international cooperation.

NASA reports

NASA Astrophysics Data System (ADS)

Obrien, John E.; Fisk, Lennard A.; Aldrich, Arnold A.; Utsman, Thomas E.; Griffin, Michael D.; Cohen, Aaron

Activities and National Aeronautics and Space Administration (NASA) programs, both ongoing and planned, are described by NASA administrative personnel from the offices of Space Science and Applications, Space Systems Development, Space Flight, Exploration, and from the Johnson Space Center. NASA's multi-year strategic plan, called Vision 21, is also discussed. It proposes to use the unique perspective of space to better understand Earth. Among the NASA programs mentioned are the Magellan to Venus and Galileo to Jupiter spacecraft, the Cosmic Background Explorer, Pegsat (the first Pegasus payload), Hubble, the Joint U.S./German ROSAT X-ray Mission, Ulysses to Jupiter and over the sun, the Astro-Spacelab Mission, and the Gamma Ray Observatory. Copies of viewgraphs that illustrate some of these missions, and others, are provided. Also discussed were life science research plans, economic factors as they relate to space missions, and the outlook for international cooperation.

Clouds on Hot Jupiters Illustration

NASA Image and Video Library

2016-10-18

Hot Jupiters are exoplanets that orbit their stars so tightly that their temperatures are extremely high, reaching over 2,400 degrees Fahrenheit (1600 Kelvin). They are also tidally locked, so one side of the planet always faces the sun and the other is in permanent darkness. Research suggests that the "dayside" is largely free of clouds, while the "nightside" is heavily clouded. This illustration represents how hot Jupiters of different temperatures and different cloud compositions might appear to a person flying over the dayside of these planets on a spaceship, based on computer modeling. Cooler planets are entirely cloudy, whereas hotter planets have morning clouds only. Clouds of different composition have different colors, whereas the clear sky is bluer than on Earth. For the hottest planets, the atmosphere is hot enough on the evening side to glow like a charcoal. Figure 1 shows an approximation of what various hot Jupiters might look like based on a combination of computer modeling and data from NASA's Kepler Space Telescope. From left to right it shows: sodium sulfide clouds (1000 to 1200 Kelvin), manganese sulfide clouds (1200 to 1600 Kelvin), magnesium silicate clouds (1600 to 1800 Kelvin), magnesium silicate and aluminum oxide clouds (1800 Kelvin) and clouds composed of magnesium silicate, aluminum oxide, iron and calcium titanate (1900 to 2200 Kelvin). http://photojournal.jpl.nasa.gov/catalog/PIA21074

The Planned Europa Clipper Mission: Exploring Europa to Investigate its Habitability

NASA Astrophysics Data System (ADS)

Pappalardo, Robert T.; Senske, David A.; Korth, Haje; Blaney, Diana L.; Blankenship, Donald D.; Christensen, Philip R.; Kempf, Sascha; Raymond, Carol Anne; Retherford, Kurt D.; Turtle, Elizabeth P.; Waite, J. Hunter; Westlake, Joseph H.; Collins, Geoffrey; Gudipati, Murthy; Lunine, Jonathan I.; Paty, Carol; Rathbun, Julie A.; Roberts, James; E Schmidt, Britney; Soderblom, Jason M.; Europa Clipper Science Team

2017-10-01

A key driver of planetary exploration is to understand the processes that lead to habitability across the solar system. In this context, the science goal of the planned Europa Clipper mission is: Explore Europa to investigate its habitability. Following from this goal are three Mission Objectives: 1) Characterize the ice shell and any subsurface water, including their heterogeneity, ocean properties, and the nature of surface-ice-ocean exchange; 2) Understand the habitability of Europa's ocean through composition and chemistry; and 3) Understand the formation of surface features, including sites of recent or current activity, and characterize localities of high science interest. Folded into these three objectives is the desire to search for and characterize any current activity.To address the Europa science objectives, a highly capable and synergistic suite of nine instruments comprise the mission's scientific payload. This payload includes five remote-sensing instruments that observe the wavelength range from ultraviolet through radar, specifically: Europa UltraViolet Spectrograph (Europa-UVS), Europa Imaging System (EIS), Mapping Imaging Spectrometer for Europa (MISE), Europa THErMal Imaging System (E-THEMIS), and Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON). In addition, four in-situ instruments measure fields and particles: Interior Characterization of Europa using MAGnetometry (ICEMAG), Plasma Instrument for Magnetic Sounding (PIMS), MAss Spectrometer for Planetary EXploration (MASPEX), and SUrface Dust Analyzer (SUDA). Moreover, gravity science can be addressed via the spacecraft's telecommunication system, and scientifically valuable engineering data from the radiation monitoring system would augment the plasma dataset. Working together, the planned Europa mission’s science payload would allow testing of hypotheses relevant to the composition, interior, and geology of Europa, to address the potential habitability of this

Jupiter radiation measurements from enhanced Galileo/EPD data for NASA's PDS archive

NASA Astrophysics Data System (ADS)

Kollmann, P.; Smith, D.; Vandegriff, J. D.; Paranicas, C.; Lee-Payne, Z. H.

2017-12-01

The Galileo mission included the first orbiter around Jupiter. Its Energetic Particle Detector (EPD) provided an excellent survey of the radiation in this planetary magnetosphere. EPD measured electrons and various ion species in the energy range of tens of keV to tens of MeV. This data set is unique since the orbit was close to the equatorial plane, covered distances from Jupiter to its magnetopause, and included several close flybys at moons. The ongoing Juno mission in comparison only skims the equatorial plane and does not include moon flybys. Even though the Galileo mission ended in 2003, the EPD data archived through NASA's Planetary Data System (PDS) is sparse and not well calibrated. The bulk of the PDS data is from a low time resolution mode (from Galileo's "real time" mode), and is only provided as count rates. Only the 14 directionally resolved channels are provided in the PDS, but there would be also 35 additional omnidirectional channels available. Data in the higher time resolution "record mode" is archived but has not been adequately corrected. We present a preliminary version of fully cleaned, calibrated, and corrected EPD data that can be used without specialized instrument knowledge. Archive products for both the updated data and also the initial raw data (all channels and resolutions) are being prepared for delivery to the PDS. Major issues with the data from the Low Energy Magnetospheric Measurements System (EPD/LEMMS) were that some channels were saturated or contaminated. We correct for this using dead times and background values determined in flight. The raw measurements of electrons in the MeV range are not resolved in energy. We ran a forward model considering the instrument response to calculate electron MeV range spectra, which have many applications. From the Composition Measurement System (EPS/CMS), we have also extracted event data, which will also be included in our PDS delivery and can be used to derive high-resolution energy spectra

Analysis and Design of a Human Spaceflight to Mars, Europa, and Titan

NASA Astrophysics Data System (ADS)

Lali, Mehdi

2010-01-01

Like Mars, Europa and Titan are worlds for which we have a special fascination. In the past two centuries, our curiosity has been stimulated by the possibility of the existence of life on Mars, and that it would be the first planet to be visited by humans. Nevertheless, there are several driving motivations that impel humans to survey Europa for astrobiological purposes and colonize Titan in order to utilize its resources. The biggest constraint for this manned spaceflight will however be the very long distances between Earth, Jupiter and Saturn. In consequence, this will lead to a very long mission duration which will be the main concern from the standpoint of human factors, especially based on our current technological capability in such fields. It is also important to note that all our eggs are currently in one basket like the dinosaurs before the extinction. If we do not make a push into space and all things go environmentally wrong, we will be just as extinct. This environmental exploration for such missions will help us save the planet and humans. In order to cut down on the mission duration, a fast transit method known as ``one-tangent-burn'' trajectory is recommended to be used instead of Hohmann transfer. But this will cost an increase in the required total ΔV. Most importantly, a rare launch-window opportunity is conceived to occur in 2078, in which these sites i.e. Mars, Europa and Titan will be aligned in such a way that they can be visited in one mission taking advantage of the gravity assists from Mars and Jupiter. This specific launch window will not recur for decades. The trajectories, orbits and planetary configurations both at the time of this launch window and arrival to these sites as well as the return missions are calculated and depicted by the computer programs designed in MATLAB for this purpose. Finally, it is shown that the gravity assist that the spacecraft receives at each swingby maneuver will drastically decrease the mission duration.

Near-infrared detection of potential evidence for microscopic organisms on Europa

NASA Technical Reports Server (NTRS)

Dalton, J. Brad; Mogul, Rakesh; Kagawa, Hiromi K.; Chan, Suzanne L.; Jamieson, Corey S.

2003-01-01

The possibility of an ocean within the icy shell of Jupiter's moon Europa has established that world as a primary candidate in the search for extraterrestrial life within our Solar System. This paper evaluates the potential to detect evidence for microbial life by comparing laboratory studies of terrestrial microorganisms with measurements from the Galileo Near Infrared Imaging Spectrometer (NIMS). If the interior of Europa at one time harbored life, some evidence may remain in the surface materials. Examination of laboratory spectra of terrestrial extremophiles measured at cryogenic temperatures reveals distorted, asymmetric nearinfrared absorption features due to water of hydration. The band centers, widths, and shapes of these features closely match those observed in the Europa spectra. These features are strongest in reddish-brown, disrupted terrains such as linea and chaos regions. Narrow spectral features due to amide bonds in the microbe proteins provide a means of constraining the abundances of such materials using the NIMS data. The NIMS data of disrupted terrains exhibit distorted, asymmetric near-infrared absorption features consistent with the presence of water ice, sulfuric acid octahydrate, hydrated salts, and possibly as much as 0.2 mg cm(-3) of carbonaceous material that could be of biological origin. However, inherent noise in the observations and limitations of spectral sampling must be taken into account when discussing these findings.

Near-infrared detection of potential evidence for microscopic organisms on Europa.

PubMed

Dalton, J Brad; Mogul, Rakesh; Kagawa, Hiromi K; Chan, Suzanne L; Jamieson, Corey S

2003-01-01

The possibility of an ocean within the icy shell of Jupiter's moon Europa has established that world as a primary candidate in the search for extraterrestrial life within our Solar System. This paper evaluates the potential to detect evidence for microbial life by comparing laboratory studies of terrestrial microorganisms with measurements from the Galileo Near Infrared Imaging Spectrometer (NIMS). If the interior of Europa at one time harbored life, some evidence may remain in the surface materials. Examination of laboratory spectra of terrestrial extremophiles measured at cryogenic temperatures reveals distorted, asymmetric nearinfrared absorption features due to water of hydration. The band centers, widths, and shapes of these features closely match those observed in the Europa spectra. These features are strongest in reddish-brown, disrupted terrains such as linea and chaos regions. Narrow spectral features due to amide bonds in the microbe proteins provide a means of constraining the abundances of such materials using the NIMS data. The NIMS data of disrupted terrains exhibit distorted, asymmetric near-infrared absorption features consistent with the presence of water ice, sulfuric acid octahydrate, hydrated salts, and possibly as much as 0.2 mg cm(-3) of carbonaceous material that could be of biological origin. However, inherent noise in the observations and limitations of spectral sampling must be taken into account when discussing these findings.

Lucy: Navigating a Jupiter Trojan Tour

NASA Technical Reports Server (NTRS)

Stanbridge, Dale; Williams, Ken; Williams, Bobby; Jackman, Coralie; Weaver, Hal; Berry, Kevin; Sutter, Brian; Englander, Jacob

2017-01-01

In January 2017, NASA selected the Lucy mission to explore six Jupiter Trojan asteroids. These six bodies, remnants of the primordial material that formed the outer planets, were captured in the Sun-Jupiter L4 and L5 Lagrangian regions early in the solar system formation. These particular bodies were chosen because of their diverse spectral properties and the chance to observe up close for the first time two orbiting approximately equal mass binaries, Patroclus and Menoetius. KinetX, Inc. is the primary navigation supplier for the Lucy mission. This paper describes preliminary navigation analyses of the approach phase for each Trojan encounter.

Mesoscale Waves in Jupiter's Atmosphere