Astronomy:Europa Lander (NASA)

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Short description: A proposed NASA lander for Europa
Europa Lander
PIA21048 - Europa Lander Mission Concept (Artist's Rendering), Figure 1.jpg
Artist's concept of the Europa Lander with Jupiter in the background
Mission typeGeology, geophysics, astrobiology
OperatorNASA
Websitewww.jpl.nasa.gov/missions/europa-lander/
Mission duration≤ 22 days on the surface[1]
Spacecraft properties
Spacecraft typeLander
Launch mass15 to 16 tons[1]
Power50 kWh (from batteries only)[1]
Start of mission
Launch dateproposed: 2025[2]
Rocketproposed: SLS Block 1B[1]
Europa lander
 
Europa
On Earth, subglacial microbial communities at Blood Falls survive in cold darkness without oxygen, living in brine water below Taylor Glacier, but come out at this location in Antarctica. The red color comes from dissolved iron.

The Europa Lander is a proposed astrobiology mission concept by NASA to Europa, an icy moon of Jupiter.[3][4] If funded and developed as a Flagship mission, it would be launched in 2025[2] to complement the studies by the Europa Clipper orbiter mission and perform analyses on site.

The objectives of the mission are to search for biosignatures at the subsurface ≈10 cm, to characterize the composition of non-ice near-subsurface material, and determine the proximity of liquid water and recently erupted material near the lander's location.

History

NASA had previously evaluated a Europa Lander concept in 2005 with the Europa Lander Mission concept.[5] Also, a lander was evaluated in 2012.[6] There was continued support for Europa missions, including in 2014, when the U.S. Congress House Appropriations Committee announced a bipartisan bill that included US$80 million in funding to continue the Europa mission concept studies.[7][8]

The United States Congress issued a congressional directive on a Europa Lander, and NASA initiated a study in 2016, assessing and evaluating the concept.[3] The mission concept is being supported by the Ocean Worlds Exploration Program.[9] NASA's Planetary Science Division delivered its report in early February 2017.[3] This was a six-month-long study by a Science Definition Team.[10][11] The study assesses the science value and engineering design of a potential Europa lander mission.[11]

Overview

The primary mission goal is detection of organic indicators of past or present life, called biosignatures.[12][3][13] The lander was described as a logical follow-up to the Galileo orbiter and probe mission in the 1990s, for which a major result was the discovery of a large sub-surface ocean that may offer habitable aquatic conditions.[10] Earth life can be found in essentially all locations where water is present. It follows that Europa is an excellent candidate in the search for life elsewhere in the Solar System.[14] This subsurface water may not only be warmed by geological activity, but likely also enriched with dissolved minerals and organic compounds.[15] Various ecosystems exist on Earth without any access to sunlight relying instead on hydrothermal vents or other sources of chemicals suitable to energy production by extremophiles[16] (see chemosynthesis). Measurements to date indicate that Europa has an ocean approximately twice the volume of Earth's oceans. This water layer below the ice may be in contact with the moon's interior allowing ready access to hydrothermal energy and chemistry.[3] A surface mission can take advantage of the relatively young, active surface of Europa as this activity may allow deep subsurface materials to regularly relocate to the surface.[17]

Status

In 18 July 2017, the House Space Subcommittee held hearings on the Europa Clipper as a scheduled Large Strategic Science Mission, and to discuss this lander as a possible follow up.[18] The President's 2018 and 2019 federal budget proposals do not fund the Europa Lander, but it did assign $195 million[19] for concept studies,[20][21] and research on the required science instruments.[22]

Objectives

The lander mission would have three main science objectives: [23]

  • Search for biosignatures.
  • Assess the habitability of Europa via in situ techniques uniquely available to a landed mission.
  • Characterize the surface and subsurface properties at the scale of the lander to support future exploration of Europa.

Spacecraft

2019 concept by JPL of the Europa Lander modules[1]

The key phases of the flight are: launch, cruise, de-orbit, descent and landing.[24] The spacecraft would consist of several modules that would be discarded at different phases of its deorbiting and landing sequence. The complete stack would be propelled by the Carrier Stage, that also features the solar panels.[1] After orbit injection around Jupiter, the spacecraft would spend about two years adjusting its orbit and velocity before attempting to land on Europa.[1]

In preparation to its landing, the Carrier Stage would be discarded, leaving the spacecraft stack in a configuration called Deorbit Vehicle (DOV) that would decelerate and initiate the descent. The engine module for this phase, called Deorbit Stage (DOS) would be discarded after the burn, leaving what is called the Powered Descent Vehicle (PDV) - which comprises the lander and the sky crane system. The sky crane system would lower the lander with a tether to a soft landing with a 100 m (330 ft) accuracy.[1]

The lander would feature a robotic arm with 5 degrees of freedom, that would enable it to dig out several shallow sub-surface samples at a maximum depth of 10 cm (3.9 in) and deliver them to its onboard laboratory.[1]

Power

Once landed, the lander would operate for up to 22 days by using chemical battery power, rather than a radioisotope thermoelectric generator (RTG) or solar power.[11][21][1] The 2019 concept proposes four batteries, which would provide three times the needed energy for safety margin during its ≈22-day surface operations.[1] The baseline is 7 days to complete its surface mission, the additional 14 days are for contingencies.[1]

Regardless of the power source, one of the limiting factors for the lifetime of the mission may be surviving radiation; the surface of Europa is estimated to experience 2.3 Mrad[1] or 540 rem per day, whereas a typical Earth surface dose is about 0.14 rem/year.[25] Radiation damaged the electronics of the Galileo orbiter during its mission.[26]

Launch and trajectory

The launcher would be the Space Launch System (SLS), with a suggested launch in 2025.[2][1] The SLS is proposed given the spacecraft's mass of 16.6 metric tons, including the solid propellant to place the spacecraft into orbit around Jupiter, and the sky crane landing system.[27] One calculated trajectory would see a launch aboard SLS in 2025, Earth gravity assist in 2027, and Jupiter/Europa arrival in 2030.[11] It would spend some time orbiting around Jupiter over the next year to maneuver for its landing on Europa.[11] The landing would be performed two years after orbit insertion around Jupiter.[1]

Landing sites

View of Europa's surface from 560 km (335 miles) altitude, as seen during the closest Galileo flyby

At Europa, it would have to land on the surface, matching its velocity, but with essentially no atmosphere there is no "entry", it is just a descent and landing.[24] The Planetary Society noted that NASA called this DDL— de-orbit, descent, and landing.[24] In 1995, astronomers using the Hubble Space Telescope discovered that Europa has a very tenuous exosphere composed of oxygen.[28] Compared to Earth, its atmosphere is extremely tenuous, with pressure at the surface predicted to be 0.1 μPa, or 10−12 times that of the Earth.[29]

The lander would communicate directly to Earth, but the Europa Clipper, if still operational, could function as an additional communications relay for the lander.[24] To ensure communication, there is a suggestion to include a telecomm orbiter with the lander mission.[30]

Surface texture

A study published in October 2018 suggests that most of Europa's surface may be covered with closely spaced ice spikes, called penitents, as tall as 15 meters (50 ft).[31][32] Although the imaging available from the Galileo orbiter does not have the resolution needed to confirm this, radar and thermal data are consistent with this interpretation.[32] This supports the need to first perform high-definition reconnaissance with the Europa Clipper and ESA's Jupiter Icy Moons Explorer (JUICE), both planned to launch in 2022, before planning a lander mission.[32][33]

Science payload

The mission concept would require funding and further development to be launched. One of the key requirements is to operate in the radiation environment at the moon's surface.[10][1] The radiation environment at Europa is extreme, so the lander may need additional protection as the Juno Radiation Vault in the Juno Jupiter orbiter.[34] The vault helped reduce radiation exposure to vulnerable systems, especially electronics on the orbiter.

NASA announced in May 2017 to the scientific community to think on possible Europa Lander instruments.[35] The concept study reports were made available in June 2019.[36]

NASA selected 14 potential instruments for maturation under Instrument Concepts for Europa Exploration 2 (ICEE-2) awarding approximately $2 million each for two years. [22] The ICEE-2 project would allow the maturation of novel instrument approaches to meet the science goals and objectives of the mission.

ICEE-2 awardees[22]
Instrument Principal investigator
C-LIFE: Cold-Lightweight Imagers for Europa Shane Bryne, University of Arizona
ELSSIE: Europa Lander Stereo Spectral Imaging Experiment Scott L. Murchie, Johns Hopkins University Applied Physics Laboratory
CORALS: Characterization of Ocean Residues and Life Signatures Ricardo D. Arevalo, University of Maryland
MASPEX-ORCA: MAss Spectrometer for Planetary EXploration-ORganic Composition Analyzer Christopher R. Glein, Southwest Research Institute
MOAB: Microfluidic Organic Analyzer for Biosignatures Richard A. Mathies, University of California Berkeley
EMILI: Europan Molecular Indicators of Life Investigation[37] W. B. Brinckerhoff, Goddard Space Flight Center
CIRS: Compact Integrated Raman Spectrometer James L. Lambert, Jet Propulsion Laboratory
ELM: Europa Luminescence Microscope Richard Quinn, Ames Research Center
SIIOS: Seismometer to Investigate Ice and Ocean Structure[38] Samuel H. Bailey, University of Arizona
ESP: Europa Seismic Package Mark P. Panning, Jet Propulsion Laboratory
MICA: Microfluidic Icy-World Chemistry Analyzer Antonio J. Ricco, Ames Research Center
MAGNET: Radiation Tolerant Magnetometer Mark B. Moldwin, University of Michigan, Ann Arbor
EMS: Europa Magnetotelluric Sounder Robert E. Grimm, Southwest Research Institute
CADMES: Collaborative Acceptance and Distribution for Measuring Europan Samples System Charles A. Malespin, Goddard Space Flight Center

Planetary protection

Planetary protection guidelines require that inadvertent contamination of a Europan ocean by terrestrial organisms must be avoided, to a probability level of less than 1 in 10,000.[39][12] The lander, and landing system components, must be assembled and tested in a clean room where all parts would have to be cleaned or sterilized before they are installed in the spacecraft. After delivering the lander, the sky crane is recommended to fly away into Jupiter for disposal.[40] At the end of the mission, the lander might self-destruct using an incendiary device.[12] That system can also be triggered if the spacecraft loses contact with the Earth.[27]

Europa Clipper

The Europa Clipper is a separately launched spacecraft that would lay a foundation for the Europa Lander mission.[3] Previously, NASA had evaluated launching the orbiter and lander together, but the strong congressional support led to an additional proposal in 2016 for a separate lander mission.[41] The Clipper orbiter will provide reconnaissance data to characterize the radiation environment and help determine a landing location.[42]

See also

References

  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 Europa Lander Mission Concept Overview. (PDF) Grace Tan-Wang, Steve Sell. Jet Propulsion Laboratory, NASA. AbSciCon2019, Bellevue, WA - June 26, 2019.
  2. ↑ 2.0 2.1 2.2 Final fiscal year 2019 budget bill secures $21.5 billion for NASA. Jeff Fout, Space News. 17 February 2019.
  3. ↑ 3.0 3.1 3.2 3.3 3.4 3.5 "NASA Receives Science Report on Europa Lander Concept". http://www.jpl.nasa.gov/news/news.php?feature=6737. 
  4. ↑ JPL moves ahead with Mars and Europa missions despite funding uncertainty. Jeff Foust. 18 July 2017.
  5. ↑ "Small RPS-Enabled Europa Lander Mission". NASA–JPL. 13 February 2005. http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/37545/1/05-0403.pdf. 
  6. ↑ "Archived copy". Archived from the original on 2017-01-26. https://web.archive.org/web/20170126025141/https://solarsystem.nasa.gov/docs/10_Europa%20Lander%20Study_L.%20Prockter.pdf. Retrieved 2017-09-09. 
  7. ↑ Khan, Amina (15 January 2014). "NASA gets some funding for Mars 2020 rover in federal spending bill". Los Angeles Times. http://www.latimes.com/science/sciencenow/la-sci-sn-federal-spending-omnibus-bill-nasa-congress-65-million-mars-2020-mission-20140115,0,7107985.story. 
  8. ↑ Girardot, Frank C. (14 January 2014). "JPL's Mars 2020 rover benefits from spending bill". Pasadena Star-News. http://www.pasadenastarnews.com/science/20140114/jpls-mars-2020-rover-benefits-from-spending-bill. 
  9. ↑ The NASA Roadmap to Ocean Worlds. Amanda R. Hendrix, Terry A. Hurford, Laura M. Barge, Michael T. Bland. Astrobiology, Vol. 19, No. 1. 2 January 2019. doi:10.1089/ast.2018.1955
  10. ↑ 10.0 10.1 10.2 Schulze-Makuch, Dirk. "A New Lander Concept for Europa". Air & Space Magazine. http://www.airspacemag.com/daily-planet/new-lander-concept-europa-180962137/. 
  11. ↑ 11.0 11.1 11.2 11.3 11.4 "Report lays out science case for Europa lander - SpaceNews.com". SpaceNews.com. 14 February 2017. http://spacenews.com/report-lays-out-science-case-for-europa-lander/. 
  12. ↑ 12.0 12.1 12.2 Europa Lander Study 2016 Report (PDF). NASA, 2016.
  13. ↑ "Report lays out science case for Europa lander - SpaceNews.com" (in en-US). SpaceNews.com. 2017-02-14. http://spacenews.com/report-lays-out-science-case-for-europa-lander/. 
  14. ↑ "NASA Report Sheds Light On Europa Lander Mission" (in en-US). https://www.yahoo.com/news/nasa-report-sheds-light-europa-074036487.html. 
  15. ↑ Coldewey, Devin. "NASA's concept Europa lander belongs on the cover of a sci-fi pulp – TechCrunch". https://techcrunch.com/2017/02/09/nasas-concept-europa-lander-belongs-on-the-cover-of-a-sci-fi-pulp/. Retrieved 9 September 2017. 
  16. ↑ "Deep sea ecology: hydrothermal vents and cold seeps" (in en). http://wwf.panda.org/about_our_earth/blue_planet/deep_sea/vents_seeps/. 
  17. ↑ Loff, Sarah (2015-05-01). "Reddish Bands on Europa" (in en). NASA. https://www.nasa.gov/content/reddish-bands-on-europa. 
  18. ↑ https://www.aip.org/fyi/2017/balance-nasa-planetary-science-missions-explored-hearing. American Institute of Physics. 21 July 2017.
  19. ↑ FY19 Appropriations Bills: NASA - Europa Missions. American Institute of Physics. 20 June 2018.
  20. ↑ Space Launch System, planetary exploration get big boosts in NASA budget. Stephen Clark, Spaceflight Now. 23 March 2018.
  21. ↑ 21.0 21.1 Europa lander concept redesigned to lower cost and complexity. Jeff Foust, Space New. March 29, 2018.
  22. ↑ 22.0 22.1 22.2 ICEE-2 Overview. Jet Propulsion Laboratory - NASA. Joel Krajewski, Payload Manager, Europa Lander PreProject. 26 June 2019.
  23. ↑ Update on the Europa Lander Mission Concept. Cynthia B. Phillips, Kevin P. Hand, Morgan L. Cable, Amy E. Hofmann, Kate L. Craft and Europa Project Science and Engineering Teams. 50th Lunar and Planetary Science Conference 2019 (LPI Contrib. No. 2132).
  24. ↑ 24.0 24.1 24.2 24.3 "NASA's audacious Europa missions are getting closer to reality" (in en). http://www.planetary.org/blogs/jason-davis/2017/nasas-audacious-europa.html. 
  25. ↑ Ringwald, Frederick A. (29 February 2000). "SPS 1020 (Introduction to Space Sciences)". California State University, Fresno. Archived from the original on 20 September 2009. https://www.webcitation.org/5jwBSgPuV?url=http://zimmer.csufresno.edu/~fringwal/w08a.jup.txt. Retrieved 5 January 2014. 
  26. ↑ "Galileo Millennium Mission Status". http://www.jpl.nasa.gov/news/news.php?feature=871. Retrieved 9 September 2017. 
  27. ↑ 27.0 27.1 "Europa lander work continues despite budget uncertainty". http://spacenews.com/europa-lander-work-continues-despite-budget-uncertainty/. 
  28. ↑ Hall, D. T.; Strobel, D. F.; Feldman, P. D.; McGrath, M. A.; Weaver, H. A. (1995). "Detection of an oxygen atmosphere on Jupiter's moon Europa". Nature 373 (6516): 677–681. doi:10.1038/373677a0. PMID 7854447. Bibcode: 1995Natur.373..677H. 
  29. ↑ McGrath (2009). "Atmosphere of Europa". Europa. University of Arizona Press. ISBN 978-0-8165-2844-8. 
  30. ↑ Telecommunications systems for the NASA Europa missions. Microwave Symposium (IMS), 2017 IEEE MTT-S International. 4-9 June 2017. doi:10.1109/MWSYM.2017.8058576
  31. ↑ Europa may have towering ice spikes on its surface. Paul Scott Anderson, Earth and Sky. 20 October 2018.
  32. ↑ 32.0 32.1 32.2 Formation of metre-scale bladed roughness on Europa’s surface by ablation of ice. Daniel E. J. Hobley, Jeffrey M. Moore, Alan D. Howard, and Orkan M. Umurhan. Nature Geoscience. 8 October 2018. doi:10.1038/s41561-018-0235-0.
  33. ↑ Jagged ice spikes cover Jupiter’s moon Europa, study suggests. Washington Post. 23 October 2018.
  34. ↑ "Here's what NASA's Europa lander could look like" (in en). Popular Science. http://www.popsci.com/heres-what-nasas-europa-lander-could-look-like. 
  35. ↑ NASA Asks Scientific Community to Think on Possible Europa Lander Instruments. NASA. May 17, 2017.
  36. ↑ Europa Lander Home Page at the Jet Propulsion Laboratory (JPL) NASA. Accessed on 22 September 2019.
  37. ↑ EMILI: Europan Molecular Indicators of Life Investigation. W. B. Brinckerhoff; A. Grubisic; S. A. Getty; R. M. Danell. ASCE Library. 16th Biennial International Conference on Engineering, Science, Construction, and Operations in Challenging Environments.
  38. ↑ "Seismometer to Investigate Ice and Ocean Structure (SIIOS)." H Bailey, R Weber, D Dellagiustina, V Bray, B Avenson, etal. 2019.
  39. ↑ Europa CLipper FAQ. NASA. 2017
  40. ↑ Landing on Europa, part 3: Proposed configuration with provisions for radiation shielding and planetary protection. Kim R. Fowler, Stephen A. Dyer. Metrology for AeroSpace (MetroAeroSpace), 2017 IEEE International Workshop on 21-23 June 2017. Italy. doi:10.1109/MetroAeroSpace.2017.7999561
  41. ↑ "NASA weighing dual launches of Europa orbiter and lander - SpaceNews.com" (in en-US). SpaceNews.com. 2016-02-01. http://spacenews.com/nasa-weighing-dual-launches-of-europa-orbiter-and-lander/. 
  42. ↑ Berger, Eric (17 November 2015). "Attempt no landing there? Yeah right—we're going to Europa". ARS Technica: pp. 1–3. https://arstechnica.com/science/2015/11/attempt-no-landing-there-yeah-right-were-going-to-europa/. Retrieved 2016-01-05. 

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