The new Trace Gas Orbiter, which arrived at Mars in October, is designed to look at trace gases in the Red Planet's atmosphere. Carbon dioxide is the major force on Mars, but there are smaller portions of the atmosphere that are less understood. One famous example is methane, which has been measured in different abundances by different telescopes, orbiters and even NASA's Curiosity rover.
TGO is highly elliptical right now, but over time it will use aerobraking - skimming through the thinnest part of Mars' atmosphere - to lower itself into a science orbit about 400 kilometers from the surface. The process is time-consuming, the European Space Agency acknowledges, but it will save fuel and also give information about the Martian atmosphere that can be used in scientific investigations.
9) Started: BEAM (International Space Station)