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Starlink satellites being lowered from 550 km to 480 km

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Re: Starlink satellites being lowered from 550 km to 480 km

#41

Post by wmf »

JumpCrisscross wrote: post #32
wmf wrote: post #24

Earlier quoted context omitted.

If the existing orbit is safe enough, why bother "increasing space safety"? The cost of this reconfiguration must be quite large. And why have no public comment period?

> If the existing orbit is safe enough, why bother "increasing space safety"? My honest guest is this is about latency more than safety. > why have no public comment period? Does the FAA require public-comment periods for plane changes?

I don't think this kind of change has ever been done before so there may not be clear regulations.

Re: Starlink satellites being lowered from 550 km to 480 km

#42

Post by montjoy »

Havoc wrote: post #14

That would surely also mean their expected lifespan is shorter too? Faster decay doesn’t just affect dead satellites Idk seems like a strange move and the stated reason seems flimsy

My take is that orbits below 500 km are “cleaned out” and during solar minimum there is less drag going on there. So, it’s a good spot to home your satellites for a while because there isn’t as much junk to maneuver around.

Re: Starlink satellites being lowered from 550 km to 480 km

#44

Post by JumpCrisscross »

londons_explore wrote: post #36
JumpCrisscross wrote: post #17

Earlier quoted context omitted.

> would surely also mean their expected lifespan is shorter too? Are Starlinks being deörbited due to propellant exhaustion? In many respects, Starlink satellites are small servers. They’re probably profitable to replace quicker than decay would force them to be.

But you don't pay for space or power - so the normal business incentives to retire old hardware don't really apply. We are nowhere close to the sky being 'full'.

> you don't pay for space or power

These birds aren’t totally autonomous. They do take up “space” in a limited sense. And having your fleet be somewhat similar lets one execute maneuvers like this global plane change more efficiently.

Re: Starlink satellites being lowered from 550 km to 480 km

#45

Post by Veedrac »

JumpCrisscross wrote: post #33
quailfarmer wrote: post #30

Earlier quoted context omitted.

For these large constellations, vehicles are generally raised slowly at the beginning of their lives, and debris spreads out as it decays downwards. A significant increase in debris at 550km would have an impact on all orbits below it, including all vehicles raising through that debris zone.

> A significant increase in debris at 550km would have an impact on all orbits below it, including all vehicles raising through that debris zone Space is huge. Try this trick: the number of satellites in orbit is about the same as the number of planes in the air at any time. (~12,000 [1][2].) The volume of space from the ground to 50,000 feet is about 200x smaller than the volume from the Karman line to the top of LE…

> The volume of space from the ground to 50,000 feet is about 200x smaller than the volume from the Karman line to the top of LEO alone (~2,000 km).

Volume is the natural way to assume space scales, but it's incorrect. Two planes can fly parallel, side by side. Two satellites cannot orbit side by side.

In the limit, if Earth had a solid ring of infinitesimal width, it would take zero volume but all orbits.

Re: Starlink satellites being lowered from 550 km to 480 km

#46

Post by cyberge99 »

londons_explore wrote: post #36
JumpCrisscross wrote: post #17

Earlier quoted context omitted.

> would surely also mean their expected lifespan is shorter too? Are Starlinks being deörbited due to propellant exhaustion? In many respects, Starlink satellites are small servers. They’re probably profitable to replace quicker than decay would force them to be.

But you don't pay for space or power - so the normal business incentives to retire old hardware don't really apply. We are nowhere close to the sky being 'full'.

Depends on how many satellites there are and how much closer they orbit.
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