Mars lake was discovered using the MARSIS radar on board the "Mars Express" orbiter, and the profiles were collected between May 2012 and December 2015. The lake is centered at 193°E, 81°S, a flat area that does not exhibit any peculiar topographic characteristics. It is mostly surrounded by higher ground except on its eastern side, where there is a depression. Mars has two relatively small (compared to Earth's) natural moons, Phobos (about in diameter) and Deimos (about in diameter), which orbit close to the planet. Asteroid capture is a long-favored theory, but their origin remains uncertain. Both satellites were discovered in
Mars Exploration Program used toward a mission that is part of the Mars Sample Return program. As a result of the smaller budget for the MEP, NASA was forced to cancel the Mars Science Orbiter planned for 2016 that would have studied the climate of the planet. NASA does not have any missions for the future of the MEP, as a plan is still being developed that will encompass the next few decades. Mars Exploration Program The Mars Exploration Program (MEP) is a long-term effort to explore the planet Mars, funded and led by NASA. Formed in 1993, MEP has made use of