Update, 17:05 ET Friday (April 9): According to EUSST, it has been observed that both objects are still intact after brushing dangerously, indicating that they have not collided.
There is a one-in-five chance that two large satellites will collide at a relative speed of 32,679 mph (52,592 km / h) over the Siberian Arctic Friday (April 9) – an event that weighs 2.1 tons (1,900 kg ) waste spreads Earth’s orbit.
The European Union for Space Surveillance and Detection (EUSST) warned on Wednesday (April 7) for the first time about the close approach between the two inactive satellites. Then, on April 8, the detection office warned that the two objects would pass within ten meters of each other, with a 20% chance of colliding.
“EUSST simulations indicate that the potential collision between the two space objects would generate more than 4 million fragments,” the agency tweeted at 9:05 ET 9 April. “More than 400 of the fragments generated by the potential collision would be larger than 20 cm [8 inches]. “
LeoLabs, a private firm, further wrote Twitter that it largely complies with the EUSST warning. But it linked the collision risk to 2% and estimated the pass distance at 44 meters.
The two orbiting objects no longer work and can not change their orbits, which are at an altitude of 790 kilometers.
Jonathan McDowell, an astronomer and astronaut at Harvard, further wrote Twitter that the larger of the two pieces of space debris is a 1.4-ton (1,400 kg) stage of a Soviet rocket used to orbit a communications satellite in May 1981. The smaller object is an American 500 kg (500 kg) meteorological satellite, known as OPS 6182 (DMSP 5D-1 F2), launched in May 1978.
Related: Here is every spaceship an astronaut has ever carried in an orbit
Space collisions have been a growing threat over the past few years as the number of satellites in space grows dramatically – including unusable, scrapped remnants. In January 2020, two different satellites came within feet of each other without colliding. Back then, astronomers? calculate that they have a 1 in 20 chance of getting stuck on each other, Live Science reported. (They missed.)
Any new debris in space also poses a threat to active satellites and human spaceflight. Objects in orbit move very fast – many times the speed of a bullet – and even a small piece of debris hitting a critical weather satellite or spacecraft can be catastrophic.
According to NASA, the long-term risk is that collisions that produce more debris are more likely than debris to accumulate in an orbit. At some point, if the problem is not addressed, there may be a “chain reaction” in space that will in fact make a low-Earth orbit too dangerous for machines or humans, which humanity’s access to and use of even the nearest parts of space for the foreseeable future. This phenomenon is known as ‘Kessler syndrome’.
According to EUSST, the two objects will move past each other today or collide at 13:18 ET. It should be clear shortly afterwards whether a disaster has occurred.
Originally published on Live Science.