Water on Mars of these salts". NASA also reported that Jake M rock, a rock encountered by "Curiosity" on the way to Glenelg, was a mugearite and very similar to terrestrial mugearite rocks. On December 9, 2013, NASA reported that Mars once had a large freshwater lake inside Gale Crater, that could have been a hospitable environment for microbial life. On December 16, 2014, NASA reported detecting an unusual increase, then decrease, in the amounts of methane in the atmosphere of the planet Mars; in addition, organic chemicals were detected in powder drilled from a rock by the "Curiosity" rover. Also, based on
Mars sample-return mission request of NASA and the NSF, declared a MSR campaign its highest priority Flagship Mission for that period. In particular, it endorsed the proposed Mars Astrobiology Explorer-Cacher (MAX-C) mission in a "descoped" (less ambitious) form, although this mission plan was officially cancelled in April 2011. In September 2012, the United States' Mars Program Planning Group endorsed a sample-return after evaluating long-term Mars' plans. The key mission requirement for the planned Mars 2020 rover is that it must help prepare NASA for its MSR campaign. which is needed before any crewed mission takes place. Such effort would require three additional vehicles: