Report about space weather causing reentry of Starlink satellites in February

https://eartharxiv.org/repository/view/3208/

by yashi • 4 years ago

75 25 4 years ago

eartharxiv.org

mikewarot• 4 years ago

I was wondering why it happened again... this refers to the events of early February.

Here's a thread from back then about it

https://news.ycombinator.com/item?id=30267587

phoe-krk• 4 years ago

Maybe it would be good to append "in February" to the topic? The current title is confusing - I see I'm not the only person who thought, "wtf, again?".

OJFord• 4 years ago

The actual title (of paper and linked page) suffixes 'in February 2022'. So it should just be that by the usual submit as-is guideline, unless that was too long.

londons_explore2• 4 years ago

I believe this was a risk spacex were deliberately taking to get more satellites launched on a single rocket.

By launching to a lower altitude initially, then more of the propulsion effort is done by the satellites themselves, and less is done by the rocket. All other things being equal, this simply means put more fuel in the satellites, and less in the rocket. Total mass is the same.

But all other things are not equal. Specifically, the satellites have 'engines' which have over 10x the specific Impulse - ie. Thrust per kilogram of fuel used.

So it makes huge sense to launch the satellites to a super low orbit and use their far more efficient engines to boost themselves up.

With the downside being the satellites ion drive engines take a long time to do the job, and if they aren't strong enough to fight against the headwind of atmospheric drag during that time, then the mission will fail.

In this case, spacex just pushed a little far.

bell-cot• 4 years ago

IIR, SpaceX talks up the initial low orbits as an important anti-space-junk measure. Starting low, any Starlink satellites which fail to power up & orient & respond to ground control commands will be fail-safe de-orbit by atmospheric drag. And they will have spent zero time at more-viable altitudes, where they might be a hazard to operational satellites.

londons_explore2• 4 years ago

Space junk isn't really a concern at any of the orbits spacex uses. They only talk about it because this anti space junk launch plan happens to be the cheapest, and it distracts from other environmental issues they don't look so good in.

bburrito• 4 years ago

I think that you have a great argument for what they were doing. But one thing to consider too is that the space weather events they launched into were known 2-3 days out. So if it was a concern they would have scrubbed the launch. I think they saw it as a good opportunity for a test and launched even though they knew they would lose some satellites. What was different about the ones successfully launched versus the ones that didnt make it?

randyrand• 4 years ago

Note: this happened in February.

Havoc• 4 years ago

They seem to be losing a lot. Could become a real issue once they get up to serious amounts of satellites.

That's what like 2% in just this incident. Not catastrophic but not insignificant either if that rate holds

DocTomoe• 4 years ago

If you have many satellites, you lose many in case of electromagnetic storms. Remember that about 25% of all satellites that currently are orbiting Earth are Starlink satellites, and that they are designed to be easily disposable and in very low orbits.

hulitu• 4 years ago

So they are designed to be crap ? Why not produce more waste ?

Retric4• 4 years ago

Around that when it happened in February, but under 2% now. 2,335 launched and 2,112 are still in orbit.

They are in low orbits to be safely disposable without risking orbital debris.

saalaa• 4 years ago

I had not realized they were going with such an incredible number of satellites. Absolutely incredible.

Report about space weather causing reentry of Starlink satellites in February

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