This is a sigh of relief for the European Space Agency (ESA). And more broadly for all the scientists involved in the Exomars 2022 mission, developed by ESA in collaboration with the Russian space agency Roscosmos. It is aimed at Mars, the Russian platform Kazachok (“little Cossack” in Russian), scientific instruments (magnetometers, seismometers, weather stations…) of the European Union that will look for traces of a possible past life. All are powered by a Russian Proton launcher from the Baikonur Cosmodrome.
But even if the rocket, platform, and rover work wonderfully, engineers for many years stumbled upon a critical element: the parachute system used to land the ship. However, tests conducted a few weeks ago are finally giving rise to optimism. All parachutes – four in total – are on! So Exomers should take off next year in September 2022.
The European rover Rosalind Franklin, the size of a golf cart, is a key element of the ExoMars 2022 mission. credit: ESA
Schiaparelli lander fell like a stone
The second part of a program that had already put the TGO probe into Mars orbit in 2016, the mission was to begin in 2018, two years after the crash of the Schiaparelli experimental lander. It was violently shaken by the opening of one of the parachutes, which caused it to spin and distorted the height measurement. Result: the retro-rockets came to a halt too early, causing the demonstrator to fall like a stone at a speed of over 500 km/h. Due to financial difficulties and a program that had no exemptions, the second phase of the ExoMars program was postponed to the next firing window (which opens approximately every two years on Mars), i.e., to the summer of 2020.
Entering the atmosphere at 21,000 km/h
But serious problems began to emerge in early 2019. He was related to the parachute system that allows spacecraft to reach the surface of Mars at near-zero speed. After about nine months of interplanetary travel, the descending module will drop into the Martian atmosphere at a speed of 21,000 km/h. To slow down, it will first use its heat shield which will absorb most of the kinetic energy, increasing the speed to 1,700 km/h.
This is when the parachute system would intervene. It is composed of two main parachutes and two smaller parachutes, called “pilots”, used to deploy them. The first parachute, 15 meters in diameter and hypersonic, will reduce the speed to 600 km / h. Second, subsonic and 35 meters in diameter – the largest ever used on Mars! -, will then be fired. During the last kilometer, the retro rockets will finally take off.
Deployment sequence of four parachutes – two main and two auxiliary – that will be used to sabotage the ship. credit: ESA
tears in the domes
But those in charge of the mission found during altitude tests in May and August 2019 that the parachutes did not open correctly: tears were seen at the level of the domes when recovered on the ground. In question, the mechanism that makes it possible to compress clothes and tens of cords into bags, which spin at speeds of up to 280 km / h. Despite NASA’s hard work and help, nothing worked. The problem could not be resolved in time. So the exoMars were unwilling to go into the same firing window in the summer of 2020 that saw the flight of the American rover Perseverance, the Chinese mission Tianwen-1 and the Emirati orbiter Al-Amal.
Company specializing in military parachutes
These problems seem to have been resolved thanks to the help of NASA’s Jet Propulsion Laboratory and the expertise of private, European and American companies. By fortifying some of the material and modifying the extraction system to make it more fluid, the two parachutes are now exposed unhindered. The first success was recorded in July 2021 in Sweden with a 15-metre parachute, the development of which was entrusted to the American company Airborne Systems. Specializing in military parachutes, it also contributed to the creation of parachutes for the Perseverance rover.
Then on November 21 and December 3, 2021, another series of tests conducted at an altitude of 29 km in Oregon (United States) showed that the 35-meter parachute was also operational. And it was the Italian supplier Ereskosmo, which also specialized in military parachutes, this time on the manoeuvre. ,Both parachutes deployed and flew perfectly, said ESA manager of the Exomars program, Thierry Blanchquart. we are on the way to launch,
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