CHEOPS - Characterising Exoplanet Satellite logo.
Nov. 5, 2020
Debris from a faulty Chinese satellite (pleonasm) threatened to pass within a few hundred meters of CHEOPS on October 2. The thrusters of the Swiss telescope had to be ignited in order to avoid at all costs a collision which would have been destructive.
Scientists were informed on September 30 that space debris was on the collision course with CHEOPS, the University of Geneva said in a statement on Thursday. Two days later, debris from the faulty Chinese satellite Fengyun 1C was to pass CHEOPS.
Space debris. Animation Credit: ESA
According to the University of Geneva, such approaches can be extremely dangerous, as objects in Earth orbit move through space at a speed several times that of a rifle bullet. A piece of one centimeter in diameter colliding with another object releases the energy of an exploding hand grenade.
According to calculations, the piece of debris from the Chinese satellite was at a dangerous distance of 500 meters from the CHEOPS telescope. The probability of a collision is then 1: 10,000.
“It may not seem very dramatic at first glance. But at enormous satellite speeds, minimal orbit deviation can have fatal consequences, ”said Christopher Broeg, manager of the CHEOPS mission at the University of Bern quoted in the statement. In the event of a collision, it could have meant the destruction of CHEOPS.
Corrected orbit
"We decided to orbit 56 meters below the previous orbit," explains Christopher Broeg. To correct the trajectory, the instrument had to be stopped on October 1 for safety reasons.
Characterising Exoplanet Satellite or CHEOPS. Image Credit: ESA
On October 2 at 12:52 a.m., the on-board computer turned on the CHEOPS control thrusters for 1.5 seconds and successfully corrected the orbit. The debris finally flew over CHEOPS on October 2 at 1:41 a.m. at a relative speed of 3140 meters per second at a distance of about one kilometer without causing damage.
High tension
When planning the mission, it was assumed that there would be a maximum of three collision warnings per year and effective orbit correction. "For the CHEOPS team, that was the first warning, which is why the tension was high at the start," exclaims Christopher Broeg.
CHEOPS aims to analyze known exoplanets to determine, among other things, whether they meet the conditions for the development of life. This project of the European Space Agency and Switzerland is placed under the responsibility of the University of Bern in collaboration with the University of Geneva.
Related links:
CHEOPS Mission Home Page: https://cheops.unibe.ch/
ESA CHEOPS: https://www.esa.int/Science_Exploration/Space_Science/Cheops
Animation (mentioned), Image (mentioned), Text, Credits: ATS/University of Geneva/Orbiter.ch Aerospace/Roland Berga.
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