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jagaerglad | 1 month ago

So instead of having to launch new satellites to replace the deorbited ones ever couple of years, do they have to send new ones every couple of months? Or can the functioning ones maintain their orbits somehow and this is only for the malfunctioning ones?

discuss

order

jws|1 month ago

It sounds like this corresponds to an atmospheric contraction. They are lowering to avoid extending the lifetime of possible debris, but that also probably means the regular lifetime is not shortened. They are just staying in the designed density to match their designed service lives. The field of view of the satellites will be reduced, but presumably they have enough units up there to maintain full coverage.

This is distinct from the FCC application they have made for another Starlink shell in VLEO (~330km) for another 15000 satellites to better serve cellular phones.

verzali|1 month ago

At 480km there will be increased drag, even as we get closer to the solar minimum. The trade-off may be between using propellant for collision avoidance vs using it to counter altitude loss and for station keeping.

Maybe it is also linked to the falling altitude of the ISS? 480km is about the upper bound of its altitude but they seem unlikely to actually raise it that high before it is deorbited.

manmal|1 month ago

They have ion thrusters that prevent them from losing altitude as long as they are operational.

JumpCrisscross|1 month ago

> ion thrusters that prevent them from losing altitude as long as they are operational

Unintentional tautology. A satellite is by definition operational as long as it can station keep.

That said, yes, they should be able to station keep with ions alone. But also, ion propulsion still requires propellant. Until we figure out orbital magnetic suspension, it’s all reaction engines.

lefra|1 month ago

They have an ion thruster to compensate for atmospheric drag.

m4rtink|1 month ago

There has been some research (IIRC by ESA) for using the upper atmosphere to feed a ion engine. That way you should be able to put satellites even lower as long as they have enough power from solar panels and are functional.