SpaceX Admits Starlink Satellite Debris Could Fall on Someone’s Head — But It Won’t Hurt

SpaceX has backed down from its previous claims that its Starlink satellites burn up completely in the atmosphere after decommissioning. The latest publication says that about 5% of the satellite’s mass is capable of reaching the Earth’s surface as non-destructible debris. For the 1,250 kg Starlink V2 satellites, this would mean 62.5 kg of debris falling on the heads of earthlings. But SpaceX urges not to worry – everything is under control!

Debris from a SpaceX rocket in the skies over Poland. Image source: Piotr/Kontakt24

SpaceX also agreed with independent scientists’ observations that the company has increased the frequency of deorbiting Starlink satellites. Observers reported that since last year, the company has been destroying 3-4 satellites per day, without explaining the reasons for such activity. SpaceX explained that this is done for safety purposes, to prevent the uncontrolled descent of emergency vehicles. Old systems are gradually replaced with new ones, this process is happening and will continue to happen every five years, which increases the safety of the satellite constellation.

In the same report, SpaceX said it was preparing to deorbit 329 Starlink satellites. The company also said it had already deorbited a total of 865 satellites, which is consistent with independent observers. In response to concerns about debris damage, the company said, “We predict that approximately 5% of the satellite mass could survive re-entry.” SpaceX had previously claimed that the Starlink V2 mini satellites would completely disintegrate in the atmosphere and that their fragments would not reach the Earth’s surface.

«The largest contribution (~90% of the surviving mass) comes from silicon from solar cells, which has a high melting point and a very low ballistic coefficient, which can result in extremely small fragments entering the atmosphere, the company added. “However, if any silicon fragments survive, they will eventually fall to Earth with an energy of less than one joule – about the energy it takes to lift an apple.” For comparison, the energy of a 4-cm hailstone falling to the ground reaches 15 joules, SpaceX explains. Thus, satellite debris, having an energy of units of joules, will not cause damage.

The company also claims to be taking a much more conservative approach to setting limits on the risk of damage. While U.S. standards require that the probability of satellite debris falling on populated areas should not exceed 1 in 10,000, SpaceX has set a much more stringent threshold for itself: 1 in 100 million. That’s why the company prefers to deorbit satellites early, before they go into emergency mode.

SpaceX also claims that it tries to bring satellites together over oceans, where the risk of causing damage is minimal. But that doesn’t change the fact that Starlink satellites are increasingly burning up in the skies over the United States, and their debris, as well as debris from rockets or boosters, occasionally makes it to the ground.