Two decades-old dead satellites have a small chance of colliding in low-earth orbit above the United States on Wednesday, according to a firm that tracks space debris.
LeoLabs has been tracking the paths of the Infrared Astronomical Satellite (IRAS) that was launched in 1983 and GGSE-4, an experimental Air Force satellite sent to space in 1967. The company announced via Twitter Monday that the pair could pass within about 50 feet of each other directly above Pittsburgh on Wednesday evening.
“On Jan 29 at (6:39 p.m. local time), these two objects will pass close by one another at a relative velocity of 14.7 km/s,” the company wrote. “These numbers are especially alarming considering the size of IRAS at 3.6m x 3.24m x 2.05m. The combined size of both objects increases the computed probability of a collision, which remains near 1 in 100.”
LeoLabs has put up an interesting online visualization of the possible collision and says it will continue to update the situation.
While a collision probability of 1 in 100 may not sound high, the tolerance of risk for such events in space is very low. A 1 in 10,000 chance of collision is considered a cause for concern in the space industry.
If the two spacecraft do collide, they’ll almost surely create hundreds or thousands of pieces of small space debris. Due to the objects’ low orbits, most of the debris will likely burn up in the atmosphere harmlessly in relatively short order. It’s unknown at this point what kind of hazard all that debris could create for other satellites in low-earth orbit. Notably, the International Space Station orbits dozens of miles lower.
“Events like this highlight the need for responsible, timely deorbiting of satellites for space sustainability moving forward,” the company said.
