They passed not far ... A space telescope launched in 1983 and an American experimental satellite from 1967, both out of service, crossed a few tens of meters Wednesday but avoided a collision which could have created thousands of debris, according to l American army.
They risked hitting each other at 15 km per second
Each satellite flew in opposite orbits and they were in danger of colliding head-on, with a relative speed of almost 15 kilometers per second. But at the appointed hour, Wednesday at 23:39 GMT (00:39 Paris time), 900 km above the city of Pittsburgh, no flash of light was observed by astronomers.
What are these two satellites?
The space telescope, IRAS, was a joint project of NASA, the United Kingdom and the Netherlands and lived 10 months. It weighs a ton, according to a database from the European Space Agency (ESA), and measures two meters by four meters by four mothers.
The American experimental satellite, GGSE-4, was launched by the US Air Force and is light (85 kg), but it has an unusual shape: it is very thin (60 cm) and is 18 meters long, and flies vertically.
Crusaders without incident
The American space command confirmed to AFP that the two machines "had crossed without incident". Harvard-Smithsonian Center engineer Jan Kansky posted a video on Twitter using a telescope showing the space telescope, IRAS, safely passing the point of impact with the satellite.
The space surveillance company AGI also wrote: "Fortunately, the first indications are that IRAS and GGSE 4 crossed without damage this evening".
Rare and dangerous collisions
These types of collisions between satellites that no one controls anymore are rare and dangerous because they can create thousands of fragments that risk destroying or damaging active satellites. In 2009, when the Iridium 33 communication satellite (active) and the Russian military satellite out of service Cosmos 2251 collided, a thousand fragments of more than 10 cm were propelled, polluting the orbits.
The probability of a collision had been evaluated at 5% by specialists from the French space agency CNES, interviewed by AFP. The company LeoLabs estimated it between 1 and 5%, which is considered very dangerous in this area.
If they had collided, the shock could have created a thousand debris over 10 cm, told AFP Dan Oltrogge, of AGI, and more than 12,000 fragments over 1 cm. The altitude of 900 km is particularly frequented by satellites.
science
Space: Batteries on US four-ton satellite threaten to explode
science
SpaceX: A shower of shooting stars spoiled by the passage of Starlink satellites
- Planet
- science
- Nasa
- Satellite