A silly mistake in calculation made the Schiaparelli lander

The European Space Agency (ESA) has released new information about the collision of the Martian ship ExoMars Schiaparelli. Immediately after deploying parachute, the ship made a miscalculation that made her think she was below the surface of Mars, while in fact it was still 3.22km away from the ground.

The ESA investigation of the collision has not yet ended, but this latest disclosure has produced a clearer picture of what happened during the failed landing on October 19. .

Schiaparelli's scorched shield.(Photo: ESA).

Schiaparelli deployed normally at a height of 12km and a speed of 1,730km / h. As planned, the ship's heat shield will be ejected when it reaches 7.8km. But since then, everything has been meaningless.

As the velocity slowed down, Schiaparelli's Inertial Measurement Center (IMU) carried out the work of calculating the speed of the ship's rotation. For some reason, the IMU has calculated the maximum saturation time to last 1-2 seconds longer than expected at this stage. When IMU sends this false information to the ship's navigation system, it calculates the negative direction. In other words, it was assumed that the lander was below the ground.

This is how Schiaparelli would invade and land.However, an error in the Inertial Measurement Center (IMU) affected the navigation system and caused the ship's computer to function as if the ship had landed (Photo: ESA).

This fateful miscalculation caused successive despair, which made the rear and rear shells prematurely, quickly heated the brake thrusters, and activated ground-based systems like Schiaparelli body has reached the surface. All of this happened when the ship was still 3.7 km from the ground, causing a free fall disaster that made the ship plummet down to 300km / h.

In an encouraging way, this action has been replicated in computer simulations, which means that these task planners have a chance to correct this anomaly. The exact cause of IMT's miscalculation is not disclosed, but if it goes wrong due to technical problems, it will be bad news. ESA is planning a similar task by 2020, so there is not much time for a technical overhaul.

High resolution image of collision area.(Photo: NASA / JPL-Caltech).

On the other hand, if it is a problem with the software, it seems easier to fix. As expected, the full report of this survey will be launched in early 2017.

Schiaparelli is the second half of the ExoMars program . The main part of the first half of the program is the Trace Gas Orbiter orbiter , the ship has successfully entered Mars orbit and is working well. Trace Gas Orbiter will begin a series of demonstrations to achieve operational trajectory by the end of 2017.