Astronauts with SpaceX’s Crew-2 mission are now safely aboard the International Space Station, but a tense moment emerged earlier when an unidentified piece of space debris threatened the CrewDragon capsule.
Approximately eight hours after launch from Kennedy Space Centre on Friday April 23, Sarah Gilles, lead space operations engineer at SpaceX, interrupted the crew as they were preparing for bed.
“For awareness, we have identified a late-breaking possible conjunction with a fairly close miss distance to Dragon, as such we do need you to immediately proceed with suit donning and securing yourselves in seats,” she said. “We will be erring on the side of caution to get you guys in a better configuration,” adding that the time of closest approach to the mystery object would be at 1:43 p.m. EDT on Saturday, April 24.
So instead of going to sleep, NASA astronauts Shane Kimbrough and Megan McArthur, along with ESA astronaut Thomas Pesquet and JAXA astronaut Akihiko Hoshide, had to put on their sleek SpaceX spacesuits, strap themselves back into their seats, and flip down their protective visors. The crew was even told to turn on their suit fans, presumably in the event of cabin depressurisation.
The exercise was done out of an abundance of caution, but sadly, it’s emblematic of a burgeoning problem: We now have way too much crap in low Earth orbit. I can’t recall a situation in which astronauts en route to the space station had to scramble back to their seats and brace for impact, but this sort of thing does happen on the ISS.
Last September, for example, the Expedition 63 crew had to temporarily relocate to the Russian segment when a piece of space debris threatened the orbital outpost. The offending object — a piece from Japan’s H-2A F40 rocket stage — came to within 1.39 kilometres of the ISS, requiring NASA and Russian flight controllers to perform an avoidance manoeuvre. The incident marked the third time in 2020 that the ISS had to be relocated on account of space debris. The same year, a pair of decommissioned satellites nearly smashed into one another, so yeah, this is starting to become normal.
The ISS, at roughly the size of a football field, represents a big juicy target up there, unlike the 8.23 m-long CrewDragon. Still, with all the stuff in space right now — both functional and non-functional — it makes sense that even relatively small vehicles like CrewDragon might also come under threat.
As if to underscore this sad fact, ESA just completed a four-day virtual conference on the subject of space debris. As the space agency pointed out in its conference backgrounder, approximately 900,000 objects larger than a AAA battery and 128 million objects larger than the thickness of a dime are currently parked in Earth orbits. At speeds approaching 56,000 km/h, even tiny bits of debris “can seriously damage or disable an operational spacecraft,” according to ESA.
Which takes us back to CrewDragon.
Thankfully, the space junk was far enough away from the capsule such that no evasive manoeuvres were required. With seconds to go before closest approach, mission controllers working at the SpaceX headquarters in Hawthorne, California, brought the crew up to speed.
“We believe the object is farther away than anticipated, lower risk of possible conjunction, but please ensure visors are closed and zippers are closed prior to [closest approach] in approximately 20 seconds,” said Gilles.
The unidentified debris flew past without incident, and at 1:44 p.m. EDT, mission control gave the all clear. The crew resumed their pre-sleep preparations, but I’d be willing to bet their heart rates were a bit higher than normal.