A large boulder, a treacherous crater or a gust of wind could jeopardise a smooth landing on Mars. Before the ExoMars Rosalind Franklin rover mission launches for the Red Planet in 2028, a replica of the landing platform went through worst-case touchdown conditions – and survived.
Thinking of every possible landing scenario, European engineers dropped a full-scale model onto a sled to test its stability in case the spacecraft touched down at an angle. A magnetic sledge released the lander at varying speeds – up to four metres per second –on a platform tilted at 20 degrees.
In every test, the four legs of the descent module absorbed the impact.
These sled-based tests were the final series of the landing platform drop test campaign conducted at the ALTEC facilities in Turin, Italy.
“This campaign proves how robust the ExoMars landing system is. The tests delivered critical data on the platform’s stability under challenging conditions, and on the ability of its legs to cope with a harsh touchdown,” says Pietro Baglioni, ExoMars rover team leader for the Rosalind Franklin mission.
The campaign also demonstrated the performance of the touchdown sensors, a critical detection function that automatically shut downs the engines upon landing. Installed in all four legs of the descent module, the sensors detect when the spacecraft approaches the surface and trigger engine shutdown. If the sensors are too slow to communicate with the propulsion system, the rocket plumes could blast martian soil upwards, potentially damaging and overturning the spacecraft.
“We want to make sure that we don’t tip over at landing. These results are fundamental to increasing confidence in the reliability of the ExoMars landing sequence,” Pietro adds.
Teams from Thales Alenia Space and Airbus are using the results from this campaign to feed computer models that simulate further landing scenarios on Mars. The Rosalind Franklin rover mission is set to arrive at the martian surface in 2030.