Mars Exploration Joint Initiative
The Mars Exploration Joint Initiative (MEJI) is an agreement signed between United states' space agency, NASA, and Europe's space agency, ESA to join resources and expertise in order to continue the exploration of the planet Mars. The agreement was signed in Washington D.C. in October 2009.
Discussions between NASA and ESA began in December 2008, driven by the ESA Ministerial Council's recommendation to seek international cooperation to complete the ExoMars mission and to prepare further Mars robotic exploration missions. At the same time, NASA was reassessing its Mars Exploration Program portfolio after the launch of its Mars Science Laboratory was delayed from 2009 to 2011. This provided NASA and ESA with an opportunity to increase cooperation and expand collective capabilities. The U.S. and Europe have taken the view that they can achieve more together scientifically at Mars if they combine their expertise. And with both parties' current Mars programmes also experiencing financial pressures, the shared approach means the exploration schedule of a mission every two years can be maintained.
The executive board recommended NASA and ESA to establish MEJI, spanning launch opportunities in 2016, 2018 and 2020, with landers and orbiters conducting astrobiological, geological, geophysical and other high-priority investigations, and leading to the return of soil and rock samples from Mars in the 2020s.
Current status 
Under the FY2013 Budget President Obama released on February 13, 2012, NASA was forced to pull out of joint Mars missions with Europe due to budgetary cuts, in order to pay for the cost overruns of the James Webb Space Telescope. The proposal for the Financial Year 2013 reduced the planetary science budget from $1.5bn to $1.2bn; Although planetary science was a loser in general, Mars exploration was singled out for particular cuts, receiving $360.8m, which amounts to a reduction of almost 40% from the FY2012 estimate. The cuts may plunge the field into its biggest crisis since the 1980s and is considered likely to lead to the loss of up to 2,000 high-tech jobs.
On February 29, 2012, the U.S. House Appropriations subcommittee that oversees NASA funding, rejected the space agency's request to begin shutting down its joint Mars-exploration effort with the European Space Agency, until the issue can be debated thoroughly. The committee believes that "so radical a change in policy needs and deserves to be fully considered by a process that is more rigorous and more inclusive than the reprogramming notification."
Regardless of the final outcome by the House Appropriations subcommittee, NASA will continue with two of its own Mars exploration projects: Mars Science Laboratory (already on Mars) and the MAVEN orbiter. No other planetary probes are funded.
In its original version, the MEJI vision would encompass the following launch opportunities:
- 2016: A European-led orbiter (Trace Gas Orbiter), to study trace gases, including methane in Mars' atmosphere. The mission would also put a static meteorological station on the surface. Europe would handle the entry, descent and landing of this station - a capability it has yet to demonstrate.
- 2018:A European rover would be dispatched to Mars. The U.S. would provide the entry, descent and landing system as being used by the Mars Science Laboratory.
- 2020: Under consideration is a network of very small landers focused on geophysics and the environment.
- NASA would provide Atlas V launch rockets in 2016 and 2018.
- The ultimate aim is a mission to return Mars rock and soils to Earth: the Mars sample return mission, some time in the 2020s.
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- "Nasa science chief 'fighting' for planetary cash". BBC News. 20 March 2012. Retrieved 2012-03-20.
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- Obama Wrecks the Mars Program (February 15, 2012)
- "Beyond the Mars Science Laboratory and MAVEN Missions". Mars Exploration Program. NASA. February 2012. Retrieved 2012-02-28.