The seven astronauts and cosmonauts onboard the International Space Station sheltered inside their respective spacecraft, a Crew Dragon and Soyuz, on Monday morning as the orbiting laboratory passed through an unexpected debris field.

This was not a pre-planned collision avoidance maneuver in low Earth orbit, in which the station would use onboard propulsion to move away. Rather, the situation required the astronauts to quickly take shelter.

Had there been a collision during the conjunction, the two spacecraft would have been able to detach from the space station and make an emergency return to Earth. Ultimately that was not necessary, and the astronauts reemerged into the space station later Monday. However, as the crew on board the station prepared for their sleep schedule, Mission Control in Houston asked them to keep as many of the hatches onboard the space station closed for the time being, in case of an unexpected collision during subsequent orbits.