Planned descent sequence of Schiaparelli Mars lander. Credit: ESA

Planned descent sequence of Schiaparelli Mars lander.
Credit: ESA

European Space Agency technicians are still in full-probe mode regarding the loss of their ExoMars 2016 Schiaparelli lander.

The vehicle crashed onto Mars on October 19th.

Schiaparelli’s atmospheric entry and associated braking occurred exactly as expected, reports ESA today.

The parachute deployed normally at an altitude of 7.5 miles (12 kilometers) and a speed of 1730 km/h. The vehicle’s heatshield, having served its purpose, was released at an altitude of 4.8 miles (7.8 kilometers).

Unexpected event

However, Schiaparelli Inertial Measurement Unit (IMU) data indicates that the craft experienced an unexpected event lasting about one second shortly after parachute deployment.

Artist's impression of Schiaparelli, the ExoMars entry, descent and landing demonstrator module, as it approaches the Martian surface. Credit: ESA/ATG medialab

Artist’s impression of Schiaparelli, the ExoMars entry, descent and landing demonstrator module, as it approaches the Martian surface.
Credit: ESA/ATG medialab

That data, when merged into the lander’s navigation system, generated an estimated altitude that was negative – that is, below ground level, ESA reports.

“This in turn successively triggered a premature release of the parachute and the backshell, a brief firing of the braking thrusters and finally activation of the on-ground systems as if Schiaparelli had already landed.”

In truth, the lander was still at an altitude of around 2.3 miles (3.7 kilometers).

The view from above of Schiaparelli crash site. Credit: NASA/JPL-Caltech/University of Arizona

The view from above of Schiaparelli crash site.
Credit: NASA/JPL-Caltech/University of Arizona

Bad behavior

This bad behavior has been clearly reproduced in computer simulations of the control system’s response to the erroneous information, ESA reports.

“This is still a very preliminary conclusion of our technical investigations,” says David Parker, ESA’s Director of Human Spaceflight and Robotic Exploration.

“The full picture will be provided in early 2017,” Parker adds, “by the future report of an external independent inquiry board, which is now being set up, as requested by ESA’s Director General, under the chairmanship of ESA’s Inspector General.”

Orbiter performing well

Meanwhile, high above Mars, the ExoMars Trace Gas Orbiter (it released the Schiaparelli lander) is performing well.

Artist’s impression of the European Space Agency's ExoMars 2016 Trace Gas Orbiter at the Red Planet.. Credit:ESA/ATG medialab

Artist’s impression of the European Space Agency’s ExoMars 2016 Trace Gas Orbiter at the Red Planet.
Credit:ESA/ATG medialab

 

The orbiter is starting its first series of science observations since arriving at the Red Planet on October 19, taking advantage of the initial parking orbit before beginning a long series of aerobraking maneuvers that will deliver the spacecraft to its operational orbit towards the end of 2017.

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