The seven crew members aboard the International Space Station had a stressful morning.
The ISS took an evasive maneuver on Friday to avoid colliding with a piece of space junk, according to Dmitry Rogozin, head of Russian space agency Roscosmos. The fragment came from a Pegasus rocket launched by the United States in 1994. The ISS deviated from its course by roughly 1,000 ft (310 m) for nearly three minutes, the agency said in a tweet.
But while the astronauts managed the encounter without any harm, the situation raises serious concerns about the future of spaceflight.
Two close calls for the ISS
NASA had announced on Tuesday that flight controllers and orbital debris specialists in Houston were “assessing the potential risk” the debris posed to the ISS. The press release identified the object as a fragment created by the breakup of the upper stage of a Pegasus rocket in 1996, two years after its launch. When that incident occurred, it was “recognized as the worst satellite breakup on record in terms of catalogued debris,” according to a report published the following year. Another 2002 report was filed that cited “a slight algorithmic error”, causing the rocket’s navigation system to “incorrectly calculate” the rocket’s position, placing it in a low orbit. Which is bad.
Friday’s maneuver marks the second time in less than three weeks that space debris has interrupted operations on the ISS. A more dangerous situation unfolded on November 15, when the crew of 7 — from the United States, Russia, and Germany — took shelter in their transport spacecraft while passing by a field of debris created by Russian military testing. A U.S. State Department spokesperson denounced the test later that day, saying the debris was the product of “a destructive satellite test of a direct ascent anti-satellite missile against one of its own satellite(s),” according to a report in Space.com. The government claims the test created more than 1,500 pieces of debris large enough to track and "hundreds of thousands of pieces of smaller orbital debris."
The growing problem of space junk
The U.S. Department of Defense currently tracks roughly 22,300 pieces of space debris, but that’s just a fraction of the millions of fragments from rocket stages, spacecraft, and satellites that still orbit the Earth. Those pieces have a total mass of at least 9,000 tons, according to Space Archaeologist Alice Gorman. That poses a problem for spacecraft and satellites, which can be damaged by even small pieces of debris. And the sheer volume of dangerous space junk is rapidly increasing. One reason is the surge in launch testing systems sending more satellites into space. Gorman is especially concerned about projects like SpaceX’s Starlink and Amazon’s Project Kuiper, which together plan to launch tens of thousands of satellites into low-earth orbit.
“I want to see some of these mega constellation operators releasing their long-term modeling for collisions as more and more satellites are launched,” said Gorman in a report from Scientific American. But alas, new launches aren’t the only source of space debris, according to retired NASA senior scientist Donald Kessler. He predicted in the 1970s that if enough space junk were to accumulate, collisions between pieces of debris would occur frequently enough to cause a runaway increase in the total number of fragments orbiting Earth. “There is now agreement within the community that the debris environment has reached a ‘tipping point’ where debris would continue to increase even if all launches were stopped,” he said in the Scientific American report.
Researchers have proposed several solutions for reducing the amount of space debris and cleaning up the junk already in orbit. OneWeb and SpaceX — companies that plan on sending a lot of satellites into orbit — are working on ways to ensure that their spacecraft will burn up in Earth's atmosphere when they become obsolete. For example, researchers in the U.S. recently described a plan to use spinning magnets to safely capture space junk, but it's unclear who would pay for and undertake the project. And, in light of Kessler's calculations, it might be too late for spacefarers to avoid this problem.