English: MAVEN's hydrazine propellant tank is shown prior to it being installed in the core structure of the MAVEN spacecraft at a Lockheed Martin clean room near Denver in this image taken in April 2012. The goal of the Mars Atmosphere And Volatile EvolutioN program, or MAVEN, is to determine the role that loss of atmospheric gas to space played in changing the Martian climate through time. The mission will determine how much of the Martian atmosphere has been lost over time by measuring the current rate of escape to space and gathering enough information about the relevant processes to allow extrapolation backward in time. Built of composite panels comprised of aluminum honeycomb sandwiched between graphite composite face sheets, the entire structure only weighs 275 pounds. MAVEN is scheduled to launch in November 2013 and will be the first mission devoted to understanding the Martian upper atmosphere.