MAVEN's main focus will be the planet's upper atmosphere to determine what happened to the Red Planet's former atmosphere - did it blow away or submerge itself into the planet's surface? India's MOM main mission was simply to arrive at Mars and thereby prove India's ability to accomplish interplanetary travel. Mission accomplished! Now that the probe is in orbit, it can begin a number of experiments to better understand the planet beneath it.
The two spacecraft join others already in orbit and still busy conducting observations, including NASA's Mars Odyssey launched in 2001 and the Mars Reconnaissance Orbiter launched in 2005, as well as the European Space Agency's Mars Express launched in 2003. Other dead spacecraft may still be circling the Red Planet, such as NASA's Mars Global Surveyor, which stopped communicating in 2007. Let's hope everyone can keep to their own orbit without colliding.
