Computer glitch probably caused ExoMars crash
Image credit: NASA
Europe’s ill-fated experimental Martian lander probably suffered from a computer problem that made it think it was already near the ground while it was still miles up in the sky.
The Schiaparelli landing demonstrator, part of the ExoMars Mission of the European Space Agency (ESA), crashed on Mars last week during a failed landing attempt.
Engineers are now analysing data from the module's descent transmitted to an orbiter that carried the probe to Mars. The team has also acquired images from other spacecraft orbiting the Red Planet.
Although the analysis has not yet been completed, the engineers believe the lander’s on-board computer somehow concluded that the probe was already nearing the surface while it was still at an altitude of more than 2km. As a result, the lander ditched its parachute too early and fired its braking rocket engines for only 4 seconds instead of the planned 29.
“My guess is that at that point we were still too high. And the most likely scenario is that, from then, we just dropped to the surface,” ExoMars project scientist Jorge Vago told Nature.com.
The rockets were meant to bring the lander to standstill 2 metres above the ground from where it would safely drop to the surface.
The researchers were able to identify the probable crash site in images acquired by Nasa’s Mars Reconnaissance Orbiter. The rather large black spot, some 15 by 40 metres in size, suggests Schiaparelli smashed into the ground at a speed of more than 300 km/h.
As the spacecraft’s fuel tanks would have still been full, the probe probably exploded upon impact.
ESA’s officials maintained the mission was still a success as the Trace Gas Orbiter, which accompanied the lander, established itself safely in a Martian orbit. They said the orbiter, which will look for traces of methane in Mars’s atmosphere, was always meant to be the main element of the mission. The lander, so they said, was only an experiment designed to verify the landing system intended to deliver a large rover in 2021.
As data from the landing sequence were successfully received, all lessons learned could now be implemented.
However, the ExoMars project, which is already delayed and over schedule, needs more funding to be able to proceed with the second part.
The timing of the mishap couldn’t have been worse as ministers of ESA’s member states are about to meet in Switzerland in a few weeks to decide whether to provide the €300m necessary to finish and launch the rover to the Red Planet in 2020.
The project faced cancellation in 2012 after ESA’s original partner American space agency Nasa withdrew following budget cuts. ESA saved ExoMars by partnering with Russia.
With Schiaparelli, ESA hoped to break the Martian curse and become only the second agency in history to successfully land an object on Mars. Only Nasa has achieved the feat so far – seven times already – but all other attempters have failed. The previous European attempt – the Beagle 2 – failed in 2003. However, unlike Schiaparelli, Beagle 2 actually made it safely to the surface, which the researchers only learned in 2014. Unfortunately, its solar panels failed to deploy properly and remained stuck blocking the craft’s antenna. Beagle 2 was therefore unable to send or receive any signal.
The ExoMars rover, which is currently being built in the UK, is meant to search for signs of life in Martian soil.
ESA hopes to image the Schiaparelli crash site with the HiRise high-resolution camera aboard Nasa’s Mars Reconnaissance Orbiter.
Since the module’s descent trajectory was observed from three different locations, the teams are confident that they will be able to reconstruct the chain of events with great accuracy.