All seven astronauts currently aboard the International Space Station are having to take shelter inside their respective spacecraft owing to the sudden appearance of a debris cloud in orbit, the source of which remains unclear.

Information is slowly trickling in, but we do know that the ISS is currently functioning normally and that all seven crew members are healthy and safe. The crew had to take shelter earlier this morning due to the sudden appearance of an orbiting debris field. The unexplained breakup of the defunct Russian satellite Kosmos-1408 is currently the leading candidate for the source of the orbiting debris cloud.

NASA astronauts Raja Chari, Tom Marshburn, Kayla Barron, and ESA astronaut Matthias Maurer are sheltering inside a SpaceX Crew Dragon docked to the ISS, while Russian cosmonauts Anton Shkaplerov, Pyotr Dubrov, and NASA astronaut Mark Vande Hei are inside a Soyuz capsule, reports Russian state-owned news agency TASS. The astronauts could use these spacecraft to safely return to Earth in the event the ISS is damaged by the debris.

A live feed of NASA mission control is available, allowing you to follow the events as they’re happening.

In a tweet, Roscosmos said the crew is “routinely performing operations according to the flight program,” and that the threatening “object” has “moved away from the ISS orbit.” By “object,” the Russian space agency is referring to the debris field. The “station is in the green zone,” Roscosmos added.

“Friends, everything is regular with us!,” tweeted Shkaplerov. “We continue to work on the program.”

Despite these words of reassurance, operations aboard the ISS are most certainly not back to normal. Mission controllers are continually providing countdowns of each debris field transit (i.e. the closest approach of the debris field to the ISS). At 10:32 a.m. ET, controllers provided instructions for the NASA crew to temporarily enter into the Columbus module to perform some quick tasks and to collect personal items should they have to remain inside Dragon overnight (a possible indication that this could take a while).

The debris field transits were happening about once every 93 minutes at first, but now they’re happening about once every 30 to 40 minutes. In an email, Harvard University astrophysicist Jonathan McDowell said that, assuming it’s a debris field caused by a broken-up satellite, “there will be a big error bar on whether there is risk to ISS, hence the caution.”

The source of the debris field remains unconfirmed, but its sudden appearance coincides with reports that Russia has conducted an anti-satellite (ASAT) weapons test. In a tweet, Gunter Krebs, a physicist and editor of Gunter’s Space Page, said the target was an “old Soviet Tselina-D SIGINT satellite called Kosmos-1408 (1982-092A) launched in 1982, which has been dead for decades,” and that ”14 debris objects have been tracked.” But Krebs cautions: “So far no confirmation from official sources.”

U.S. Space Force “is aware of a debris-generating event in outer space” and is “working to characterize the debris field and will continue to ensure all space-faring nations have the information necessary to maneuver satellites if impacted,” tweeted space reporter Joey Roulette from the New York Times.

Today’s incident comes less than a week after the ISS had to make an emergency maneuver to evade potentially threatening space junk. In that case, it was a remnant of the Fengyun-1C weather satellite, which China deliberately destroyed in 2007 as part of an anti-satellite missile test. India did something similar in 2019, joining the United States, Russia, and China as countries that have tested anti-satellite weapons. Currently, the use of ASATs “occupy a gray zone” when it comes to international arms control, writes Talia M. Blatt from Harvard University.  

This is a developing story and we will update this article as we learn more.