On 19th October, the European Space Agency rejoiced as its first ExoMars mission successfully completed one of two initial goals. The Trace Gas Orbiter was finally in orbit around its red planet target. However, rejoicing gave way to scratched heads and furrowed brows as the second part of that phase remained in question. The Schiaparelli lander had mysteriously vanished after it detached from the orbiter to land on the surface. Its remains were found three days later and now the ESA has released its initial findings on what may have caused its premature demise.
The ExoMars Schiaparelli was meant to test the ESA’s and partner Rokosmos of Russia’s ability to land a rover on Mars. In that sense, it might have failed that initial test. The lander remained in contact even after being deployed from the TGO and deploying its parachutes. Then after that, radio silence.
Three days later, NASA’s Mars Reconnaissance Orbiter (MRO) found what is believed to be the crash site and parts of the Schiaparelli. So, yes, the lander did crash, which explains for the loss in communication. What wasn’t immediately evident, however, was why.
Data gathered from the lander as well as images from orbiters have given ESA scientists a working theory as to the cause. The Schiaparelli’s parachute did deploy as intended at a height of 12 km and a speed of 1,730 km/h. The problem was that the inertial measurement unit (IMU), which measures the lander’s rotation, and the navigation system erroneously fed the computer data about its current altitude. To the lander, it would seem that it already landed, even below ground level, so it detached its parachute, briefly fired its braking thrusters, and activated on-ground systems. In reality, it was still a good 3.7 km above the surface.
The ESA hasn’t closed the books yet on the case and doesn’t expect the investigation to end until early 2017. It is, however, unfazed by the setback and sees the experience as a learning opportunity. The ESA and its international partners are preparing another ExoMars mission in 2020 that will land a more sophisticated, and more expensive, rover.