The Mars Atmosphere Volatile Evolution mission, or MAVEN, is NASA's newest mission to Mars. After a 10 month journey, it's arriving at the Red Planet on Sunday, September 21, where it will study the planet's upper atmosphere. MAVEN will help determine why Mars has lost the majority of its atmosphere over the past four billion years, giving us information on how the Mars climate has evolved over time. This will also help us understand the evolution of other planets, including Earth.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 22.214.171.124.0