Space can be an unforgiving environment, even for a spacecraft. The Canadian Space Agency (CSA) has just reported that a small hole has appeared in a robotic arm it operates aboard the International Space Station (ISS) – driving home the risks of space junk.
The 5-mm-diameter hole was noticed during a routine inspection of the exterior of the spacecraft on 12 May 2021, but it’s unknown what the object was or when it hit.
In a statement, CSA notes that despite the impact to the robotic arm Canadarm2, its performance remains unaffected, and “the damage is limited to a small section of the arm boom and thermal blanket”.
The impact was called a “lucky strike”, as it didn’t impact operations or any of the seven astronauts aboard the ISS.
But the danger of space junk is ever-present – and only increasing as new satellites are launched into orbit.
Earth is surrounded by an ever-growing population of man-made junk, left over from old spacecraft, obsolete satellites and debris from collisions, for example the 2009 collision between a defunct Russian spacecraft and a US commercial satellite. As of 2020, the US Space Surveillance Network was tracking over 14,000 bits of debris larger than 10cm across, but there are estimated to be many millions of pieces smaller than that.
This might not seem like a huge problem, but when travelling at the blistering speeds of Earth orbit (up to eight kilometres per second!) even a tiny speck of debris could damage spacecraft or operational satellites.
Plus, since most pieces of space junk are too small to be monitored, the threat of collision is taken very seriously by space agencies – in fact, several windows of NASA’s space shuttle fleet previously sustained damage from orbiting paint flecks.
Luckily, scientists are on the case around the world – the Australian National University, for example, recently announced they’re partnering with industry to develop lasers to push space debris out of orbit, while the Southern Cross Outreach Observatory Project wants to deploy a network of mobile observatories across Australia to create a detailed database of orbiting junk.