The ExoMars Schiaparelli lander may have suffered a software glitch that caused it to crash into the Martian surface at 186 miles per hour, according to European Space Agency (ESA) mission leads quoted Tuesday in Nature.
By Becky Ferreira | MOTHERBOARD
The lander’s last messages back to Earth indicate that the error occurred four minutes and 41 seconds into its entry, descent, and landing (EDL) sequence on Wednesday, October 19. At this late point in the lander’s six-minute-long EDL, its onboard computer system prematurely jettisoned the heat shield and parachutes, apparently because Schiaparelli thought it was much closer to the surface than it was in reality.
The module then fired its retrorockets, but only for three seconds, instead of the 30-second-long burn that had been planned to guide it down to a gentle landing. This truncated burn may also have been prompted by the lander’s confusion over its altitude. Though it was about two-to-four kilometers (roughly one-to-three miles) above the surface when the rockets fired, it behaved as if it was only a few meters from the ground, switching off its engine early to initiate the landing.
This conclusion is further validated by the fact that, as it hurled towards the crashsite, Schiaparelli activated its onboard instruments, designed to take temperature, pressure, and electric field readings. To the ExoMars team, this suggests that the module thought that it had successfully stuck the landing and was getting ready to radio information about its surface surroundings back to its home world.