Low Earth orbit can be a dangerous place, as a recent incident involving Canadarm2 confirms.
A small chunk of space junk has pierced Canadarm2, creating a discernible hole on the robotic device, the Canadian Space Agency has revealed in a statement. Ths CSA is calling it a “lucky strike,” as Canadarm2, attached to the International Space Station, remains functional despite the gaping wound.
That the arm got hit by some kind of mystery object should not come as a major surprise. Low Earth orbit is a veritable junkyard, one filled with millions of bits of human-spawned debris. Things like defunct satellites, rocket parts, busted bits of spacecraft, and even flecks of paint clutter the region of space. Radar can currently track the estimated 34,000 objects larger than 3.9 inches (9.9 centimeters) currently floating in low Earth orbit, but anything smaller is basically invisible to us.
But just because these fragments are small doesn’t mean they’re not dangerous. Space debris measuring a few millimeters across can still inflict tremendous damage due to the intense velocities involved, as speeds in low Earth orbit can reach 6 miles per second (10 kilometers per second). These errant objects cannot be monitored from the ground, but they represent ongoing threats to space-based resources and human life. And unfortunately, it’s currently technologically infeasible and economically impractical to clear the estimated 6,000 tons of debris from low Earth orbit.
The hole on Canadarm2 was detected during routine inspections of the device on May 12. Experts with the CSA and NASA analyzed detailed images of the arm to determine the extent of the damage. The hole, at an estimated quarter-inch (6-millimeters) across, is located on one of the arm’s boom segments, which is fortunate.
“Despite the impact, results of the ongoing analysis indicate that the arm’s performance remains unaffected,” the CSA stated. “The damage is limited to a small section of the arm boom and thermal blanket.”
Astronauts aboard the ISS will continue to use Canadarm2, including a planned operation to replace a faulty power switchbox.
The ISS has been struck by space debris before. Back in 2016, a quarter-inch diameter chip was spotted on one of the space station’s windows. The blemish was caused by a “fragment no bigger than a few thousandths of a millimeter across,” according to the European Space Agency. To penetrate an ISS module, an object would need to be at least a half-inch (1.3-centimenters) wide, while objects larger than around 4 inches (10 centimeters) would outright destroy or shatter entire sections. Hopefully we’ll find a way to clean up our space junk before something truly tragic happens.