Panic aboard the International Space Station (ISS). A cloud of debris nearly threatened mankind’s most expensive construction, as well as its seven crew members overnight from Monday to Tuesday. Faced with the danger, the astronauts were forced to take refuge in their vessel, in order to be able to evacuate in the event of excessive collisions.
Everything seems to be back to normal although no impact has yet been identified. 20 minutes takes stock of this story.
Where does this cloud of debris come from?
The United States on Monday accused Russia of firing a “dangerous and irresponsible” anti-satellite missile, which allegedly caused the debris cloud. “This test has so far generated more than 1,500 traceable orbital debris, and will likely generate hundreds of thousands of smaller pieces of orbital debris,” US Foreign Minister Antony Blinken said in a statement.
“I am scandalized by this irresponsible and destabilizing action,” added the head of the US space agency, Bill Nelson. “The orbit of the object, which forced the crew to go to the spacecraft today according to standard procedures, has moved away from the orbit of the ISS, the agency tweeted. Russian space Roscosmos. The station is now in the green. “
The trajectory of this debris has never directly threatened the ISS, specifies Olivier Sanguy, scientific mediator of the city of space in Toulouse, that 20 minutes questioned. But their orbits fell within the safety margins of the international station. “The closing of the hatches of the ISS or the installation of the astronauts in their spaceship were more of the caution”, specifies the expert.
This is not the first time that a missile test to destroy a satellite has been carried out. Russia has done this before, as have India, China and the United States. The interest is to be able in the event of conflict to destroy adversary satellites, become essential for telecommunications, in particular military. The maneuver is however strongly criticized, in particular because of the number of wild debris it causes.
“Normally, such a test should not have been carried out so close to the ISS,” says Olivier Sanguy. It should be noted, however, that the Russian military agency, and not the space agency, was responsible for this. As the maneuver was military and could be considered a defense secret, there was no absolute obligation to warn the International Space Station. “
Can debris really be dangerous for the ISS?
Absoutely. Of course, the International Space Station has thick armor, but as Olivier Sanguy reminds us, it revolves around the earth at a speed of 28,000 km / h. At such a speed, an impact, despite heavy armor, can hurt. “It’s not a question of the size of the debris, but of the relative speed. Kind of like a bullet. Hand-thrown at someone, it’s way too small to hurt. Pulled by a rifle, it arrives at such a speed that it can kill, ”describes Olivier Sanguy.
In a 2007 NASA report, the American space agency estimated that “the risk of penetration of a micrometeoroid or orbital debris in the ISS in its configuration in complete assembly is of 55% with a risk of 9% of a catastrophic result over a period of 10 years. In addition, debris accumulated after this period, further elevating the risk.
To counter these risks, the ISS can make evasive maneuvers, in particular using thrusters. “However, it requires significant anticipation and seeing the debris coming. We cannot divert the ISS from its orbit like that, ”notes Olivier Sanguy.
Will space debris eventually make space impractical?
In the medium term, the risk seems more to be a less accessible space than really impracticable. “The lifespan of satellites could be greatly reduced due to the greater probability of encountering space debris,” said Olivier Sanguy. For the moment, a satellite in low orbit has an estimated lifespan of between 10 and 15 years, and becomes more out of service due to failures related to the hostile environment of space. Too much accumulation of space debris could reduce the lifespan of satellites to less than 10 years, “making the various space operations more expensive and costly due to the greater number of satellites required”, concludes the scientific mediator.
The various space agencies, well aware of the problem and its potential economic impact, are starting to offer charters of good conduct: arranging for old satellites to reach the atmosphere in order to be consumed there, leaving less space debris when sending rockets, etc.… For the moment, there is nevertheless no really binding text on this subject, plus a guide to good practices to be encouraged.