The spacecraft comprises two separate instruments: the Trace Gas Orbiter (TGO) and the Schiaparelli landing demonstration module. Once in orbit the TGO will perform detailed observations of the Martian atmosphere, searching for evidence of gases indicative of the existence of biological life, such as methane.
— BBC Science Focus Magazine (@sciencefocus) October 17, 2016
Also, at this point the Schiaparelli lander will be ejected from the orbiter towards the Red Planet, entering the atmosphere at 21,000km/h before using a combination of thrusters, aerobraking and parachutes to land on the surface. Once safely on solid ground, the lander will deploy its payload of scientific instruments to take measurements the atmospheric conditions on the surface.
The lander will only remain operable for a few days but the TGO will stay in orbit for five years, waiting for the arrival of a second rover in 2020 that will drill into the surface of the Red Planet.
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