The ISS had to fire its thrusters to avoid Russian space junk — again

The International Space Station (ISS) had to fire its thrusters once again this week to avoid Russian space junk.

The orbital station fired its thrusters for a total of five minutes and five seconds in a "Pre-Determined Debris Avoidance Maneuver," NASA explained in a blog post.

The maneuver was carried out at 8:25 p.m. ET on Monday, October 24, and it's the latest example of the ISS having to avoid the increasing amount of space debris in orbit — an issue that was exacerbated last year when Russia blew up one of its own defunct satellites as part of a weapons test.

The ISS moves to avoid Russian space shrapnel

NASA says the maneuver increased the ISS's altitude by between 0.2 and 0.8 miles. For obvious reasons, the space agency operates with an abundance of caution when it comes to avoidance maneuvers. It states that, without the move, the Russian satellite space debris would have come within 3 miles of the ISS.

The avoidance maneuver was initiated due to a fragment from Russia's Cosmos 1408 satellite. As per NASA, when Russia destroyed that satellite as part of an anti-satellite weapon test in November 2021, it created 1,500 pieces of debris.

At the time, U.S. officials condemned the weapon test as wreckless, citing the danger of Kessler Syndrome, which would see space debris increase dramatically in a snowball effect. When small pieces of debris collide with other pieces of space shrapnel, they create more debris, further increasing the probability of more collisions.

Russia isn't the only entity criticized for worsening the space debris problem. China has recently also faced criticism for allowing its Long March 5 rocket cores to become dangerous space debris that has the potential to fall over populated areas.

U.S. firm SpaceX has also faced criticism from the astronomical community, and astronomers have even organized to call for more regulation of the private company's satellite mega-constellation launches.

The growing space debris problem

Unsurprisingly, NASA's mode of operation is to be extremely cautious in the face of a potential catastrophic space debris collision — the space agency says it performs an avoidance maneuver even when there is a one in 100,000 chance of a small piece of space debris hitting the ISS. The U.S. Department of Defense and NASA both track and classify space debris with their global Space Surveillance Network (SSN) sensors.

Space debris is a big problem, with NASA stating that there are roughly 25,000 pieces of debris larger than 10 cm in orbit and approximately 500,000 pieces measuring between 1 cm and 10 cm in diameter. These pieces of debris travel through orbit at the speed of bullets — flying at up to 33,000 mph.

NASA does state that the ISS should be able to withstand impacts of objects roughly 1 cm in diameter. The ISS typically moves roughly once every year to avoid space debris, though this will likely increase in the coming years as the space debris problem only becomes more urgent — the space station also had to perform an unscheduled avoidance maneuver as recently as June.

The U.S. space agency has relied on Russia to perform thrust avoidance maneuvers in recent years. However, as of June this year, it can perform re-boosts using Northrop Grumman's robotic Cygnus cargo spacecraft, following a test with the U.S.-built spacecraft.