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hubie writes:

Nine science instruments were selected to fly on the NASA mission to Jupiter's moon Europa. The instruments will study the moon from its atmosphere to its subsurface. The instruments are (as copied from the NASA press release):

• Plasma Instrument for Magnetic Sounding (PIMS) -- principal investigator Dr. Joseph Westlake of Johns Hopkins Applied Physics Laboratory (APL), Laurel, Maryland. This instrument works in conjunction with a magnetometer and is key to determining Europa's ice shell thickness, ocean depth, and salinity by correcting the magnetic induction signal for plasma currents around Europa.
• Interior Characterization of Europa using Magnetometry (ICEMAG) -- principal investigator Dr. Carol Raymond of NASA's Jet Propulsion Laboratory (JPL), Pasadena, California. This magnetometer will measure the magnetic field near Europa and – in conjunction with the PIMS instrument – infer the location, thickness and salinity of Europa's subsurface ocean using multi-frequency electromagnetic sounding.
• Mapping Imaging Spectrometer for Europa (MISE) -- principal investigator Dr. Diana Blaney of JPL. This instrument will probe the composition of Europa, identifying and mapping the distributions of organics, salts, acid hydrates, water ice phases, and other materials to determine the habitability of Europa's ocean.
• Europa Imaging System (EIS) -- principal investigator Dr. Elizabeth Turtle of APL. The wide and narrow angle cameras on this instrument will map most of Europa at 50 meter (164 foot) resolution, and will provide images of areas of Europa's surface at up to 100 times higher resolution.
• Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) -- principal investigator Dr. Donald Blankenship of the University of Texas, Austin. This dual-frequency ice penetrating radar instrument is designed to characterize and sound Europa's icy crust from the near-surface to the ocean, revealing the hidden structure of Europa's ice shell and potential water within.
• Europa Thermal Emission Imaging System (E-THEMIS) -- principal investigator Dr. Philip Christensen of Arizona State University, Tempe. This "heat detector" will provide high spatial resolution, multi-spectral thermal imaging of Europa to help detect active sites, such as potential vents erupting plumes of water into space.
• MAss SPectrometer for Planetary EXploration/Europa (MASPEX) -- principal investigator Dr. Jack (Hunter) Waite of the Southwest Research Institute (SwRI), San Antonio. This instrument will determine the composition of the surface and subsurface ocean by measuring Europa's extremely tenuous atmosphere and any surface material ejected into space.
• Ultraviolet Spectrograph/Europa (UVS) -- principal investigator Dr. Kurt Retherford of SwRI. This instrument will adopt the same technique used by the Hubble Space Telescope to detect the likely presence of water plumes erupting from Europa's surface. UVS will be able to detect small plumes and will provide valuable data about the composition and dynamics of the moon's rarefied atmosphere.
• SUrface Dust Mass Analyzer (SUDA) -- principal investigator Dr. Sascha Kempf of the University of Colorado, Boulder. This instrument will measure the composition of small, solid particles ejected from Europa, providing the opportunity to directly sample the surface and potential plumes on low-altitude flybys.

takyon writes:

A NASA report on the potential for future exploration of the Jovian moon Europa has been published:

A report on the potential science value of a lander on the surface of Jupiter's icy moon Europa has been delivered to NASA, and the agency is now engaging the broader science community to open a discussion about its findings.

[...] The report lists three science goals for the mission. The primary goal is to search for evidence of life on Europa. The other goals are to assess the habitability of Europa by directly analyzing material from the surface, and to characterize the surface and subsurface to support future robotic exploration of Europa and its ocean. The report also describes some of the notional instruments that could be expected to perform measurements in support of these goals.

Scientists agree that the evidence is quite strong that Europa, which is slightly smaller than Earth's moon, has a global saltwater ocean beneath its icy crust. This ocean has at least twice as much water as Earth's oceans. While recent discoveries have shown that many bodies in the solar system either have subsurface oceans now, or may have in the past, Europa is one of only two places where the ocean is understood to be in contact with a rocky seafloor (the other being Saturn's moon Enceladus). This rare circumstance makes Europa one of the highest priority targets in the search for present-day life beyond Earth.

Executive summary:

The Europa Lander Science Definition Team Report presents the integrated results of an intensive science and engineering team effort to develop and optimize a mission concept that would follow the Europa Multiple Flyby Mission and conduct the first in situ search for evidence of life on another world since the Viking spacecraft on Mars in the 1970s. The Europa Lander mission would be a pathfinder for characterizing the biological potential of Europa's ocean through direct study of any chemical, geological, and possibly biological, signatures as expressed on, and just below, the surface of Europa. The search for signs of life on Europa's surface requires an analytical payload that performs quantitative organic compositional, microscopic, and spectroscopic analysis on five samples acquired from at least 10 cm beneath the surface, with supporting context imaging observations. This mission would significantly advance our understanding of Europa as an ocean world, even in the absence of any definitive signs of life, and would provide the foundation for the future robotic exploration of Europa.

Europa Lander Study 2016 Report (264 pages) and older resources.

Original Submission

Phoenix666 writes:

Saturn's icy moon Enceladus is best known for its numerous geysers ejecting plumes of water and ice. These eruptive fountains perplex researchers searching for signs of microbial life beyond Earth. A dedicated spacecraft designed to study the plume-like features spewing from Enceladus could definitely tell us whether or not they contain alien microorganisms.

"We need a spacecraft to travel to Enceladus, fly through a geyser plume, and analyze the water that is immediately accessible," Geoffrey Marcy, a retired professor of astronomy at the University of California, Berkeley, told Astrowatch.net.

Marcy is a renowned exoplanet researcher who discovered many extrasolar worlds. He was one of the co-investigators of NASA's Kepler planet-hunting mission that detected more than 4,000 exoworlds.
...
"The remarkable aspect of the search for microbes in the water spurting from geysers is that the spacecraft only needs to fly through the plume, well above the surface of Enceladus. No lander is needed—just a succession of flybys through the plumes as it orbits Enceladus," Marcy said.

He noted that such spacecraft should be fitted with a mass spectrometer to detect organic compounds that could be signs of microbial life. The spectrometer will look for amino acids and the structure of any organic molecules, especially fatty acids such as those composing cell membranes. It could also measure the relative amounts of isotopes of carbon (12 and 14) to detect non-natural anomalies due to biological processes.

Moreover, the mission to Enceladus would measure the properties of the water such as pH, oxidation and temperature, therefore assessing its suitability for organic life.

Marcy believes assembling "a brilliant team of billionaires" is the key to making such a mission possible. Lucky for him the monolith said nothing about Enceladus.

Original Submission

takyon writes:

Plate tectonics on Jupiter's moon Europa could make finding life there more likely:

Earthquakes could be fueling life on Europa, one of Jupiter's moons. Scientists have shown that huge chunks of the moon's ice crust could be sinking others, infusing its underground ocean with chemical food. [...] Geophysicists from Brown University in Providence, Rhode Island, have shown that tectonic activity is also feasible within Europa's ice shell. They used a computer simulation to map subduction—where one giant slab of ice is forced under another.

The gravitational pull of moons could extend the unfrozen lifetime of subsurface oceans on some objects, such as Pluto and Charon:

Heat generated by the gravitational pull of moons formed from massive collisions could extend the lifetimes of liquid water oceans beneath the surface of large icy worlds in our outer solar system, according to new NASA research. This greatly expands the number of locations where extraterrestrial life might be found, since liquid water is necessary to support known forms of life and astronomers estimate there are dozens of these worlds.

"These objects need to be considered as potential reservoirs of water and life," said Prabal Saxena of NASA's Goddard Space Flight Center in Greenbelt, Maryland, lead author of the research published in Icarus [DOI: 10.1016/j.icarus.2017.11.023] [DX] November 24. "If our study is correct, we now may have more places in our solar system that possess some of the critical elements for extraterrestrial life."

List of largest lakes and seas in the Solar System.

Also at Brown University (EurekAlert).

Porosity and salt content determine if subduction can occur in Europa's ice shell (open, DOI: 10.1002/2017JE005370) (DX)

Original Submission

takyon writes:

Future Europa landers may be in danger of sinking into a surface less dense than freshly fallen snow:

Space scientists have every reason to be fascinated with Jupiter's moon Europa, and, in 2017, NASA and the European Space Agency (ESA) announced they are planning a joint mission to land there. As the video above explains, this little moon is thought to have a liquid ocean submerged beneath an icy crust. Scientists believe it could host extraterrestrial life. But Europa's surface is much more alien than any we've ever visited. With its extremely thin atmosphere, low gravity – and a surface temperature of some -350 degrees F. (–176 °C.) – Europa might not be kind to a landing spacecraft. The moon's surface might be unexpectedly hard. Or – as evidenced by a study from the Planetary Science Institute announced on January 24, 2018 – Europa's surface might be so porous that any craft trying to land would simply sink.

The study – published in the peer-reviewed journal Icarus – comes from scientist Robert Nelson. If you're a student of space history, its results might sound familiar. Nelson pointed out in his statement:

Of course, before the landing of the Luna 2 robotic spacecraft in 1959, there was concern that the moon might be covered in low density dust into which any future astronauts might sink.

Now Europa is the source of a similar scariness, with Nelson's study showing that Europa's surface could be as much as 95 percent porous.

Laboratory simulations of planetary surfaces: Understanding regolith physical properties from remote photopolarimetric observations (DOI: 10.1016/j.icarus.2017.11.021) (DX)

Original Submission

takyon writes:

While water plumes have been imaged on Saturn's icy moon Enceladus by the Cassini spacecraft, evidence for plumes on Jupiter's moon Europa has been scarce. But a new analysis found that a magnetometer aboard the Galileo spacecraft recorded signs of a plume in 1997, years before the Cassini spacecraft encountered plumes:

Scientists have new evidence that there are plumes of water erupting from the surface of Jupiter's icy moon Europa — plumes that could, maybe, possibly contain signs of life. The evidence comes from data collected by the now-defunct Galileo spacecraft. Although the data has been available since it was collected in 1997, it's only now that an analysis confirms the existence of water plumes.

For more than two decades, scientists have been convinced Europa has a liquid water ocean sloshing around beneath its icy outer crust. In the past six years, two teams of researchers using the Hubble Space Telescope reported the possible existence of plumes. But as powerful as Hubble is, seeing something as small as a plume on a moon more than 380-million miles away is difficult. "We're looking for effects that are relatively small, and are pushing the spatial resolution of the telescope," says astrophysicist Susana Deutsua of the Space Telescope Science Institute.

Congressman John Culberson, known for his support for the Europa Clipper mission, broke the research embargo in a recent hearing on NASA's budget.

Also at Ars Technica and The Verge.

Evidence of a plume on Europa from Galileo magnetic and plasma wave signatures (open, DOI: 10.1038/s41550-018-0450-z) (DX)

Original Submission

takyon writes:

Saturn moon a step closer to hosting life

Scientists have found complex carbon-based molecules in the waters of Saturn's moon Enceladus.

Compounds like this have only previously been found on Earth, and in some meteorites. They are thought to have formed in reactions between water and warm rock at the base of the moon's subsurface ocean.

Though not a sign of life, their presence suggests Enceladus could play host to living organisms. The discovery came from data gathered by the Cassini spacecraft.

Also at SwRI, ScienceAlert, Space.com, National Geographic, Popular Mechanics, and The Guardian.

Macromolecular organic compounds from the depths of Enceladus (DOI: 10.1038/s41586-018-0246-4) (DX)

Related: Minerals In Plumes of Enceladus Indicate Hydrothermal Activity
Hydrogen Emitted by Enceladus, More Evidence of Plumes at Europa
Could a Dedicated Mission to Enceladus Detect Microbial Life There?
How the Cassini Mission Led a 'Paradigm Shift' in Search for Alien Life
Cassini Spacecraft Post-Mortem
Porous Core Could be Keeping Enceladus Warm
Yuri Milner Considering Privately Funded Mission to Enceladus
Organic Molecules Found on Ceres
NASA Finds Evidence of Water Plume on Europa
Organic Matter Found on Mars
Study Finds Evidence of More Organic Material on Ceres

Original Submission

takyon writes:

Fields of five-story-high ice blades could complicate landing on Jupiter moon

Probes have shown that Europa's ice-bound surface is riven with fractures and ridges, and new work published today in Nature Geosciences suggests any robotic lander could face a nasty surprise [DOI: 10.1038/s41561-018-0235-0] [DX], in the form of vast fields of ice spikes, each standing as tall as a semitruck is long.

Such spikes are created on Earth in the frigid tropical peaks of the Andes Mountains, where they are called "pentinentes,"[sic] for their resemblance to devout white-clad monks. [...] Pentinentes[sic] have already been seen on Pluto. And by calculating other competing erosional processes on Europa, such as impacts and charged particle bombardment, the new work suggests the vaporization of ice would be dominant in its equatorial belt, forming pentitentes[sic] 15 meters tall spaced only 7 meters apart. Such formations could explain, the authors add, why radar observations of the planet dip in energy at its equator, the pentinentes[sic] scattering the response. But the ultimate proof of whether Europa's belly will be off limits to landing will come when the Clipper arrives in the mid-2020s.

[Update: It's penitentes. Ed.]

First it was slush. Now it's spikes. Attempt no landing there.

Europa.

Also at Science News and The Verge.

Related:
NASA Releases Europa Lander Study 2016 Report
Amino Acids Could Exist Just Centimeters Under Europa's Surface

Original Submission

takyon writes:

Mission to Jupiter's Icy Moon Confirmed

An icy ocean world in our solar system that could tell us more about the potential for life on other worlds is coming into focus with confirmation of the Europa Clipper mission's next phase. The decision allows the mission to progress to completion of final design, followed by the construction and testing of the entire spacecraft and science payload.

[...] The mission will conduct an in-depth exploration of Jupiter's moon Europa and investigate whether the icy moon could harbor conditions suitable for life, honing our insights into astrobiology. To develop this mission in the most cost-effective fashion, NASA is targeting to have the Europa Clipper spacecraft complete and ready for launch as early as 2023. The agency baseline commitment, however, supports a launch readiness date by 2025.

Also at Ars Technica, The Register, CNN, and CNET.

Related: Amino Acids Could Exist Just Centimeters Under Europa's Surface
Impact of the Midterm Elections May be Felt at NASA
White House Budget Request Would Move Launches from SLS to Commercial Providers

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