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Starlink satellites being lowered from 550 km to 480 km

35 points

by wmf

2 hours ago

| past

| 3 comments

| twitter.com

| HN

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vipa123

6 minutes ago

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How much Delta-V would that take, and how much would they typically have onboard at the start of their life?

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jagaerglad

1 hour ago

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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?

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jws

1 hour ago

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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.

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verzali

1 hour ago

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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.

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manmal

1 hour ago

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

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lefra

1 hour ago

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They have an ion thruster to compensate for atmospheric drag.

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m4rtink

33 minutes ago

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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.

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wmf

1 hour ago

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Usually orbits are reserved years in advance. AFAIK this kind of move is unprecedented (although everything about Starlink is unprecedented since it's the first megaconstellation).

Two weeks ago, a Starlink satellite exploded. SpaceX believes it wasn't caused by a collision which means the explosion was probably caused by a malfunction in the satellite itself. Now 4,400 Starlink satellites are moving to a lower orbit for "safety". Is this an emergency change to account for a design flaw that they just discovered?