A satellite called the Trace Gas Orbiter (TGO) has sent back its first images from Mars. The satellite began orbiting Mars in October. Scientists are currently testing its sensors. The TGO will help scientists study the gases that make up Mars’ atmosphere. In particular, they will look for methane. Methane is a simple molecule. Scientists would expect Mars’ harsh environment to destroy it. However, the air on Mars consistently contains small amounts of methane. Scientists want to find the source of this gas. Some think the source could be a form of microbial life.