ESA: Mars lander crash caused by 1-second inertial measurement error

Source: SpaceNews.com

ESA: Mars lander crash caused by 1-second inertial measurement error

by Peter B. de Selding — November 23, 2016

PARIS — The European Space Agency on Nov. 23 said its Schiaparelli lander’s crash landing on Mars on Oct. 19 followed an unexplained saturation of its inertial measurement unit, which delivered bad data to the lander’s computer and forced a premature release of its parachute.

Polluted by the IMU data, the lander’s computer apparently thought it had either already landed or was just about to land. The parachute system was released, the braking thrusters were fired only briefly and the on-ground systems were activated.

Instead of being on the ground, Schiaparelli was still 3.7 kilometers above the Mars surface. It crashed, but not before delivering what ESA officials say is a wealth of data on entry into the Mars atmosphere, the functioning and release of the heat shield and the deployment of the parachute — all of which went according to plan.

Awaiting a December go-ahead for ExoMars 2020

Schiaparelli was never intended to survive more than a few days on the Mars surface, but the the crash-and-die scenario has nonetheless made for bad press in Europe, raising concern that ESA governments might struggle to find the 300 million euros ($330 million) needed to finish funding a 2020 mission with Russia.

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Read more: http://spacenews.com/esa-mars-lander-crash-caused-by-1-second-inertial-measurement-error/

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Source: Gizmodo

A Crazy Miscalculation Doomed the Schiaparelli Lander

George Dvorsky
Today 3:19pmFiled to: MARS

The European Space Agency has released new information about the crash of the ExoMars Schiaparelli lander. Soon after the deployment of its parachute, the lander made a miscalculation so bad that it thought it was below the Martian surface, when in reality was still two miles high.

The ESA’s investigation into the crash is far from over, but this latest revelation is painting a clearer picture of what happened during the failed landing on October 19.

Schiaparelli deployed its parachute normally at an altitude of 7.5 miles (12 km) and at a speed of 1,075 miles per hour (1,730 km/h). As planned, the vehicle’s heat shield was ejected when it reached an altitude of 4.85 miles (7.8 km). But things went to complete shit from there.

As it was making its slow descent, Schiaparelli’s Inertial Measurement Unit (IMU) went about its business of calculating the lander’s rotation rate. For some reason, the IMU calculated a saturation-maximum period that persisted for one second longer than what would normally be expected at this stage. When the IMU sent this bogus information to the craft’s navigation system, it calculated a negative altitude. In other words, it thought the lander was below ground level. Ouch.

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Read more: http://gizmodo.com/a-crazy-miscalculation-doomed-the-sciaparelli-lander-1789319670