International Space Station fires thrusters to avoid satellite
The International Space Station had to maneuver out of the way of an Earth-imaging satellite on Monday (March 6).
At approximately 7:42 a.m. (12:42 GMT), the thrusters on the Progress 83 supply ship currently docked with the International Space Station (ISS) fired for just over six minutes, raising the station’s orbit to prevent possible collision, NASA said in a blog post (opens in new tab).
The satellite in question appears to have been an Argentine Earth observation satellite launched in 2020, according to Sandra Jones of NASA’s Johnson Space Center. In a post on Twitter (opens in new tab), Dr. Jonathan McDowell, an astronomer and astrophysicist at the Harvard-Smithsonian Center for Astrophysics, narrowed the possible candidates down to Nusat-17, noting the constellation’s orbital decay.
Related: International Space Station: Facts about the orbital laboratory
Nusat-17 is one of ten commercial observation satellites launched in 2020 and operated by geospatial data company Satellogic. As McDowell points out in his tweet, the constellation Nusat is one of several whose orbits are slowly encroaching on the orbit of the ISS.
Evasive maneuvers like this are not entirely uncommon for the space station. According to a December 2022 NASA report (opens in new tab), the ISS has made a total of 32 course corrections to avoid traceable satellites and space debris since 1999.
A graph showing the numbers of ISS collision avoidance maneuvers between 1999 and 2023 (image credit: NASA’s Orbital Debris Program Office (ODPO))
Last year, two such corrections were needed to avoid debris from the Cosmos 1408 satellite, which Russia destroyed in an anti-satellite weapons (ASAT) test in November 2021 — a demonstration that has since been largely condemned by the community. international space.
Monday’s course correction came with ample notice, with NASA receiving initial alerts about the potential collision roughly 30 hours before the satellite’s predicted closest approach, Jones told Space.com. A predetermined avoidance maneuver (PDAM) was calculated and crews aboard the ISS along with ground crews from NASA and Roscosmos prepared for the planned propellant burn. However, “about 20 minutes before PDAM, a ‘green update’ was received on the link,” Jones said, adding, “the thrusters were already engaged, so the burn was still complete.”
Monday’s PDAM comes amid heavy traffic for the ISS and just days after the arrival of SpaceX’s Crew Dragon Endeavor and members of Crew-6. Within the next week, astronauts aboard the space station will say goodbye to members of Crew-5, scheduled to launch as early as Thursday (March 9), and begin preparing for the arrival of SpaceX CRS payloads -27 Dragon, currently planned. to start on March 14.
NASA’s blog post says the March 6 avoidance maneuver will not affect Crew-5’s upcoming launch. In her statement to Space.com, Jones confirmed that position, adding, “this burn does not interfere with the stages for any future traffic of the space station.” NASA announced Wednesday afternoon that Crew-5 would leave the ISS at 5:05 p.m. March 9, for a planned splashdown at 9:25 p.m. March 10.
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