In the midst of the US government shutdown, a bit of positive news came out of NASA today. The MAVEN mission to Mars has been declared essential to the American people. This allows the workers assembling and testing the spacecraft to return to work during the shutdown and puts the mission back on track for a mid-November launch.
Note: the MAVEN mission was developed at and is operated by my employer, the Laboratory for Atmospheric and Space Physics at the University of Colorado - Boulder. I do not have inside information on the status of any aspect of the mission.
So why is it essential for the American people to understand the composition of the Martian atmosphere? It's not, it turns out. From the government's perspective, MAVEN serves a far more important purpose as a communications satellite. Rovers on the surface of Mars communicate with controllers on Earth via the Deep Space Network - basically the internet of space. Spacecraft in orbit about Mars provide a vital link in this system. Currently, this role is fulfilled by Mars Odyssey and Mars Reconnaissance Orbiter. Launched in 2001 and 2005, respectively, these aging satellites serve as the only links between Earth and the Curiosity and Opportunity rovers. If MAVEN were to slip to a launch in 2015 or later, it's possible that all contact could be lost with these invaluable assets.
Of course, launching MAVEN to serve its role as a communications satellite doesn't preclude its use for science. An on-time launch will give the mission a unique opportunity to view a comet before arriving at Mars to help uncover its history.