ESA space ferry saves ISS from near miss with debris
Sen—The International Space Station has just had its closest brush with disaster. ESA’s ATV cargo vessel Georges Lemaître used its thrusters to push the orbiting outpost and its six occupants out of harm’s way when it was threatened by space debris.
This is the first time the ISS's international partners have avoided space debris with such urgency.
Ground stations keep tracking space junk for potentially life-threatening collisions. A fleck of paint can cause major damage travelling at 28,800 km/h. Most of the time, the radar network gives ample warning, but sometimes a dangerous object can slip through the net or its erratic behaviour makes accurate predictions difficult.
On 27 October, a piece of Russia’s Cosmos-2251 satellite that broke up after colliding with another satellite in 2009, was on a collision course with the Space Station. The object was around the size of a hand and calculations showed it would pass within 4 km.
Six hours before potential impact the ATV Control Centre team in France commanded a four-minute thruster burn starting at 17:42 GMT (18:42 CET) that triggered a boost of 1.8 km/h in the Automated Transfer Vehicle (ATV-5), enough to raise the 420-tonne Station by 1 km.
ATV-5 Georges Lemaître approaching Station. Image credit: Roscosmos–O. Artemyev
Although this debris avoidance used a predefined manoeuvre, great care was taken to make sure that the move did not push the Station into a worse orbit or affect the docking of last week's Progress.
“This is what the ATV Control Centre team trains for,” said ESA flight director Jean-Michel Bois. “Seven days a week, 24 hours a day, we are ready to react and we practise often in simulations. “Reacting so quickly to save the Space Station in real life was tense but rewarding.”
“The debris avoidance demonstrates ATV’s reliability and the great team behind mission control,” said ESA’s ATV-5 mission manager Massimo Cislaghi. “With this manoeuvre, ATVs have met every requirement of the original design.”
ATV-5 Georges Lemaître over Earth. Image credit: Roscosmos–O. Artemyev
The versatile ATVs have achieved many firsts for ESA. They are the largest European spacecraft ever launched and the only non-Russian vehicle to dock automatically with the Station.
After delivering more than 6.6 tonnes of supplies, fuel and gases, to the ISS, Georges Lemaître will undock in February and burn up harmlessly in the atmosphere, after demonstrating a new shallow reentry for planning Station decommissioning.
ATV technology will also supply power and life-support for NASA’s next generation Orion spacecraft, designed to carry a crew to deep space destinations such as an asteroid and eventually Mars.