When Mars’s orbit brings it particularly close to Earth, the planet takes on a striking red colour. This sight has captured human imagination since antiquity: Is there life on Mars? That’s by no means improbable since Mars is more similar to Earth than any other planet in our solar system.
Five decades of Mars research
Scientists have been putting unmanned space probes into orbit around Mars for more than 50 years. Today, we know that water – essential to the development of life – has left traces on the planet’s surface. Analysing such traces is the aim of the European Space Agency’s (ESA) Mars Express mission.
European space probe: in orbit for more than ten years
Launched from Baikonur Cosmodrome in Kazakhstan on 2 June 2003, the Mars Express probe has been orbiting the Red Planet for more than ten years. On board are seven scientific instruments, including a special camera. The High Resolution Stereo Camera, or HRSC for short, which was developed at the German Aerospace Center (DLR) in Berlin, is Germany’s principal contribution to the Mars mission.
Pictures from Mars: more detailed than ever before
The camera enables the systematic and three-dimensional scanning of a planet’s surface for the first time. Five sensors scan the surface from different angles. At the DLR Institute of Planetary Research, the individual pictures are combined to produce three-dimensional coloured images. On these, it is possible to make out objects ranging in size between ten and 30 metres. If a telephoto lens is used, it is even possible to discern objects of two to three metres.
Water in a volcanic crater
The Mars Express researchers have recently discovered rock formations on the images of a volcanic crater showing that water has flowed down the inner walls of the crater at regular intervals – most recently hundreds of thousands of years ago. For planetary researchers accustomed to thinking in millions of years, that’s as if it happened yesterday.
No sign of Martians – but microorganisms
“The pictures of Mars have shown us where there was water, i.e. areas that were particularly conducive to life,” says Tilman Spohn, head of the DLR Institute of Planetary Research. Microorganisms – tiny, mostly single-celled organisms that can endure extreme conditions on Earth as well – may have lived there.
The search continues
Another Mars mission is to be launched in 2018. It will carry a drill developed by the DLR that can collect samples at depths of up to five metres. Perhaps the Mars rocks will provide a definitive answer to the question of whether there is – or has ever been – life on Mars as we know it on Earth.