NASA

The International Space Station (ISS) changed course Friday to avoid a possible collision with a piece of an old Pegasus rocket.

A chunk of that old rocket, which broke apart two years after the United States launched it into Earth’s orbit in 1994, was on track to pass close to the ISS Friday morning. NASA and Russia’s space agency, Roscosmos, monitored the chunk throughout Monday, eventually deciding they needed to move the space station.

About two hours before the debris was set to pass the ISS, at 2:58 a.m. ET, Roscosmos fired the engines of its Progress cargo spacecraft, which was docked to the ISS, pushing the orbiting laboratory closer to Earth. The two-and-a-half-minute engine burn lowered the space station’s altitude by 310 meters — about 1,000 feet — setting it on a new path, safely out of reach of the rocket chunk.

Because predicting the path of debris in Earth’s orbit isn’t exact, mission controllers routinely move the ISS when objects are expected to pass close by. Friday marked the second time the ISS had to change course in order to avoid debris this year, including once last month, when Russia swerved the station away from a piece of junk. In 2020, the orbiting laboratory had to dodge debris on three occasions.

During its two decades orbiting Earth, the ISS has moved to avoid space junk at least 30 times.

RTFA for details, ongoing problems, the importance of keeping space tidy.