Ask Jorge Vago, the project scientist for the soon-to-be-launched ExoMars mission, to describe its purpose and this is what he says:
Essentially our spacecraft is a giant nose in the sky.
Scheduled to launch on March 14th from the Baikonur cosmodrome in Kazakhstan, the European Space Agency’s ExoMars mission will place the Trace Gas Orbiter in position to use its highly sensitive spectrometers to detect – if they exist – extremely low levels of methane gas, which would be another indicator besides water that there is or once was life on Mars.
The Trace Gas Orbiter will look at the planet from two angles. At dawn and dusk, the spectrometers will point directly at the Sun. Between those times, they will look straight down at the surface to look for methane hot spots. Either way, they will be able to detect as little as a few parts per trillion. The instruments will also look for other gases, like sulfur dioxide, which will help determine if any methane found was created by life forms or from geological processes such as volcanic eruptions.
Finally, the orbiter will release a small landing craft called Schiaparelli (named for a 19th century Italian astronomer who drew early maps of Mars) to take precise measurements from the atmosphere as it descends to help plan for Phase 2 of the mission – the launch of the six-wheeled ExoMars Rover in 2018. Schiaparelli will also help scientists decide where to land the ExoMars Rover to take full advantage of its ability to drill 2 meters below the surface (Curiosity’s drill can only descend a few centimeters) to look for organic material. An ancient riverbed would be an ideal choice.
It’s nice to see rocket scientists showing their sense of humor with the “giant nose in the sky” description of Phase 1 of the ExoMars mission. Let’s hope they stop before describing the giant hole the methane came out of.