Europa Lander

NASA had previously evaluated a Europa Lander concept in 2005 with the Europa Lander Mission concept. Also, a lander was evaluated in 2012. 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. The United States Congress issued a congressional directive on a Europa Lander, and NASA initiated a study in 2016, assessing and evaluating the concept. NASA's Planetary Science Division delivered its report in early February 2017. The study assesses the science value and engineering design of a potential Europa lander mission. The Europa Lander was considered by the Planetary Science Decadal Report of 2023─2032 but rejected in favor of the Uranus Orbiter and Probe and Enceladus Orbilander. Eventually, the plans for such a lander were shelved in 2025. == Overview ==

The primary mission goal was to detect of organic indicators of past or present life, called biosignatures. 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. This subsurface water may not only be warmed by geological activity, but likely also enriched with dissolved minerals and organic compounds. 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 (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. 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. The president's 2018 and 2019 federal budget proposals do not fund the Europa Lander, but they did assign US$195 million for concept studies Eventually, the plans for such a lander was shelved in 2025. == Objectives ==

The lander mission would have three main science objectives: • 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 ==

of the Europa Lander modules The 2019 concept proposes four batteries, which would provide three times the needed energy for safety margin during its ≈22-day surface operations. It is estimated that the probe would receive a total ionizing dose of 2.3 Mrad over the 30 day mission. == Launch and trajectory ==

The launcher would have been the Space Launch System (SLS), with a suggested launch between 2025-2030. 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. One calculated trajectory would see a launch aboard SLS in 2025, Earth gravity assist in 2027, and Jupiter/Europa arrival in 2030. It would spend some time orbiting around Jupiter over the next year to maneuver for its landing on Europa. The landing would be performed two years after orbit insertion around Jupiter. == Landing sites ==

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. ;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). 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. == 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. The radiation environment at Europa is extreme, so the lander may need as much additional protection as the Juno Radiation Vault in the Juno Jupiter orbiter. 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. The concept study reports were made available in June 2019. NASA selected 14 potential instruments for maturation under Instrument Concepts for Europa Exploration 2 (ICEE-2) awarding approximately US$2 million each for two years. The ICEE-2 project would allow the maturation of novel instrument approaches to meet the science goals and objectives of the mission. == 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. 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. At the end of the mission, the lander might self-destruct using an incendiary device. That system can also be triggered if the spacecraft loses contact with the Earth. == Europa Clipper ==

The Europa Clipper is a separately launched spacecraft that would lay a foundation for the Europa Lander mission. The Clipper orbiter will provide reconnaissance data to characterize the radiation environment and help determine a landing location. == See also ==