After their takeoff on February 3, the last 49 Starlink satellites were in very low orbit, the time to test their onboard systems. A solar storm generated an increase in atmospheric drag, which slowed down the satellites. Result: 40 units are already or will be disintegrated shortly.
However, there is no danger for populations on the ground.
It’s not us, it’s the Sun
This is a solar storm that will cost SpaceX dearly, as the company deploys new efforts to try to monetize its internet connectivity service via orbit, with already more than 2,000 satellites.
The take-off on February 3 had however gone well, with an ejection of the 49 satellites in low orbit, followed by an individual contact and an evaluation of the on-board systems. The Californian company sends its units into a very low orbit, with a perigee (the point closest to Earth) of only 210 kilometers above sea level. This has advantages, for example saving energy for the Falcon 9 launcher, or the fact that if a satellite does not perform well, it will be disintegrated in the atmosphere within weeks of take-off. Unfortunately for SpaceX, less than 24 hours after the launch, the effects of a solar storm reached Earth, with dire consequences.
Satellite vs atmosphere
Solar storms, unless very intense, generally have little impact on satellites in low orbit, protected by the (famous) Van Allen belts. But they often involve a change in density in the very high layers of the atmosphere: the latter is not a “bubble” that stops at an altitude of 100 kilometres.
For satellites in very low orbit, below 300 kilometers, the effect is immediate: braking induced by the friction of atmospheric particles. SpaceX says its newly ejected satellites were subjected to 50% more friction! Inevitably, in this situation, emergency measures must be taken… But there is not much to do on these units weighing several hundred kilos, since they are propelled with small ion engines. They were therefore switched to backup mode in an attempt to make them fly “on edge” and present their most aerodynamic profile.
The tile
Alas, that will not have been enough: 40 of the 49 units have re-entered or will re-enter the atmosphere, and the fate of the last 9 was not specified in the SpaceX press release. The company stresses the care it takes to produce satellites that burn up 100% without letting any debris fall to the surface, but also the fact that these very low orbits help to pose the fewest possible traffic problems in space.
The event is unprecedented, even if almost 10% of the 2,100 Starlink units sent into space since 2019 are deactivated, already disintegrated or on the way… The significant loss rate has increased further. And even if SpaceX funds both the flight campaign and the production (which involves shipments at cost), it’s a blow to the tens of millions of dollars. Inevitable?
Source:
SpaceX
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