2024-02-13 16:18:00
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A satellite orbits the earth. (Artist’s impression) © IMAGO/Zoonar
Esa can only watch the impending crash of the ERS-2 satellite. Nevertheless, the huge satellite is not said to pose any danger.
Frankfurt – When a 1.3-ton satellite crashed last July, the European Space Agency had an active hand in it. The agency planned to set a standard for the disposal of space debris with the active crash of the Aeolus satellite. And in fact: until shortly before its end, Esa gave the satellite commands and managed to cause it to burn up in an uninhabited region.
However, this will not be possible with the next satellite crash that is imminent. However, the crash of the ERS-2 satellite, which weighs more than two tons, poses no danger, as ESA emphasizes.
Esa observes 2-ton satellite ERS-2 crashing
The next satellite ready to crash has been waiting for this moment for many years. ERS-2 is an Earth observation satellite launched into Earth orbit in April 1995. At that time, it was the most modern Earth observation spacecraft ever developed and launched by Europe, says ESA. Regardless of whether it was land surfaces, oceans, polar ice caps or natural disasters – ERS-2 had everything in view and provided experts on Earth with important data from orbit.
Current crash forecast
Esa currently assumes that the ERS-2 satellite will arrive on… February 19, 2024 at 11:26 p.m. (CET) falls to earth. However, this date is very imprecise – it can shift by up to 38 hours in any direction. (As of: February 12, 2024, 5:00 p.m.)
In 2011 it was decided to shut down the satellite and remove it from Earth’s orbit so as not to leave space debris behind. Since the satellite was at an altitude of 785 kilometers at the time, this was not a quick affair. With the remaining fuel remaining, the satellite’s orbit was lowered to 573 kilometers. This minimized the risk of the satellite colliding with other spacecraft or space debris. This was also intended to ensure that the satellite crashes to Earth within 15 years.
ESA’s ERS-2 satellite is expected to fall to Earth in mid-February and burn up
Now the time has come: ERS-2 is getting closer and closer to Earth. The satellite is expected to crash into Earth around mid-February 2024 – in contrast to the “Aeolus” crash, without any involvement from ESA. Because once the satellite reaches an altitude of around 80 kilometers, physics will take over: the satellite will inevitably crash.
ERS-2 had a mass of 2,516 kilograms when it took off; without the fuel, it is now around 2,294 kilograms, Esa estimates. But the two-ton satellite is not a danger: a large part of the device is expected to burn up in the atmosphere. Individual fragments that could survive the torrid ride through the Earth’s atmosphere are very likely to fall into the sea.
The risk of being hit by space debris on Earth is very low
“The annual risk that a single person will be injured by space debris is less than 1 in 100 billion,” writes the ESA on its website. This is 65,000 times lower than the risk of being struck by lightning and three times lower than the risk of being struck by a meteorite. “The risk on the ground from re-entries is very small,” emphasized the head of the ESA space debris department, Tim Flohrer, in a media interview about the “Aeolus” crash. “To date, no one on the ground has been harmed.”
The satellite is currently under permanent observation. Nevertheless, Esa cannot estimate exactly when the crash will take place. “Because re-entry is ‘natural,’ it is impossible to predict exactly when and where the satellite will begin to burn up,” the space agency said. “The window in which re-entry is possible will continue to shrink.”
Natural re-entries into the Earth’s atmosphere are difficult to calculate
Natural re-entries into the Earth’s atmosphere are difficult to calculate because it is not known exactly how dense the respective layers of the Earth’s atmosphere are. These layers provide the “pulling” that brings the satellite closer and closer to Earth. The closer they are, the faster a satellite sinks towards Earth. The density is also influenced by solar activity, among other things.
In the case of “Aeolus,” the crash was accelerated by solar activity. In the case of a set of “Starlink” satellites, solar activity even caused brand-new satellites to crash shortly after launch. One thing is already certain: ERS-2 will come down. The only question is when and where. (tab)
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