Cape Canaveral, Florida: Two new science satellites are being prepared to join a fleet of robotic Mars probes to help determine why the planet most like Earth in the solar system ended up so different.
India's Mars Orbiter Mission, the country's first interplanetary foray, is due to blast off on November 5 from the Satish Dhawan Space Centre in Sriharikota, India.
Billed as a pathfinder to test technologies to fly to orbit and communicate from Mars, the satellite follows India's successful 2008-2009 Chandrayaan-1 moon probe, which discovered water molecules in the lunar soil.
The Mars Orbiter Mission has ambitious science goals as well, including a search for methane in the Martian atmosphere. On Earth, the chemical is strongly tied to life.
Methane, which also can be produced by non-biological processes, was first detected in the Martian atmosphere a decade ago.
But recent measurements made by NASA's Mars rover, Curiosity, show only trace amounts of methane, a puzzling finding since the gas should last about 200 years on Mars.
India's Mars Orbiter Mission also will study Martian surface features and mineral composition.
Also launching in November is NASA's Mars Atmosphere and Volatile Evolution, or MAVEN, spacecraft.
MAVEN will focus on Mars' thin atmosphere, but rather than hunting methane, it is designed to help scientists figure out how the planet managed to lose an atmosphere that at one time was believed to be thicker than Earth's.
"MAVEN is going to focus on trying to understand what the history of the atmosphere has been, how the climate has changed through time and how that has influenced the evolution of the surface and the potential habitability - at least by microbes - of Mars," lead mission scientist Bruce Jakosky, with the University of Colorado at Boulder, told reporters on a conference call on Monday.
MAVEN is due to launch on November 18 from Cape Canaveral Air Force Station in Florida and reach Mars on September 22, 2014 - the day after India's spacecraft arrives.
They will join two NASA rovers, two NASA orbiters and a European Space Agency satellite already studying Mars.