The debris should pass within “several kilometres” of the International Space Station (ISS), but out of an abundance of caution, its trajectory was being changed to move it further away from the object.
The three crew members – two Russians and an American – relocated to their Soyuz spacecraft as the manoeuvre began so they could evacuate if necessary, Nasa said.
“Manoeuvre burn complete. The astronauts are coming out of safe haven,” Nasa chief Jim Bridenstine said on Twitter.
The “time of closest approach” was 22.21 GMT, Nasa said.
The ISS is orbiting roughly 260 miles (420km) above the Earth, at a speed of about 17,130mph (27,568km/h). At such a velocity, even a small object could seriously damage a solar panel or other facet of the station.
This type of manoeuvre is necessary on a regular basis. Nasa said 25 such manoeuvres had occurred between 1999 and 2018.
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