What happens when satellites collide

Satellite collision warning: the probability of a crash is more than 20 percent

A European consortium for the surveillance of satellites warns of a possible collision of two satellites in Earth orbit on Friday. The probability of a crash is now over 20 percent, tweeted the so-called EU Space Surveillance and Tracking Support Framework (EUSST) on Friday night. It still looks like the two satellites will miss each other by less than 10 meters. The consortium first warned mid-week that the probability was over one percent. The two satellites are therefore a Russian rocket stage and a US weather satellite.

Dangerous space junk

One of the two satellites is therefore a former US Air Force weather satellite that was launched in 1978. It has a mass of several hundred kilograms and is therefore acutely on a collision course with a Soviet missile stage that has been circling the earth since 1981. Further observation time has now been requested in order to be able to observe the two objects more closely and take further measurements, it said on Thursday. The collision at an altitude of almost 800 kilometers, which cannot yet be ruled out, would therefore take place on Friday afternoon, with possibly immense consequences.

The possible crash in orbit, which would create debris that could endanger other satellites, once again illustrates the dangers of space debris. At the beginning of 2020, a similar near collision had caused nervousness, but the two satellites had finally missed each other. Before this, ESA, accompanied by loud criticism, had saved one of its satellites from a possible - albeit unlikely - collision with one of SpaceX. The US space company is currently sending satellites into orbit at high speed in order to set up the Starlink satellite internet. Others are currently working on plans to remove inactive satellites from orbit.

[Update 04/09/2021 - 12:55 p.m.] In the meantime, the experts have added that a possible collision could result in more than four million fragments, 400 of which could be more than 20 centimeters in diameter.

[Update 04/09/2021 - 10:45 p.m.] Several hours after the two objects came closest to each other, the experts have now announced that two individual signals are still being registered. This means that the collision did not materialize and both satellites are still intact.

The article includes an interactive graphic that is created and delivered by the Berlin service provider Datawrapper. For data protection at Datawrapper, see their data protection declaration. Personal or personally identifiable data from readers of the interactive chats are not collected.


Read comments (73) Go to homepage


Don't miss any news! Every morning the fresh news overview from heise online

E-mail address

You can find detailed information on the dispatch procedure and your cancellation options in our data protection declaration.

Ad ad