zoicyte t1_j9q8opb wrote
Reply to comment by morningcoffee1 in What will be the environmental impact of de-orbiting 42,000 Starlink satellites every five years? (Explanation in post) by OvidPerl
here's a real answer:
don't be too worried about the 23 500-lb satellites that will also vaporize alongside the 44 tons of space rocks that already do the exact same thing.
tonyvila t1_j9qqkng wrote
Except your numbers are quite wrong. Each satellite weighs about 1200 kg, so each one is over a ton (~2600 lb). That's almost 60 tons, which is a 130% increase in pure mass, not to mention chemical composition.
fastspinecho t1_j9qx65q wrote
No, the first-generation satellites weigh only 250 kg.
SpaceX eventually plans to put second-generation satellites into orbit, which do weigh ~1200 kg. However, they will need fewer of them, because they are more powerful than the first-generation satellites. They are not currently capable of putting many of these into orbit, and only have permission to launch 7500 of them in the future.
Spacex ultimately plans for the first-generation satellites to constitute 75% of its fleet.
CMDR_Shazbot t1_j9rasrx wrote
Yep, also people aren't factoring in that the initial approval is best effort. Maybe they applied for 42k and claim they have a 5 year lifespan, but the reality is they want them to last longer and would be much happier doing it with fewer satellites. 5 years is under certain conditions and likely lowballed, if they don't need to do collision avoidance maneuvers could be longer, if there's a lull in space weather could be longer, if there's a lot of that could be shorter.
The gen 2s require starship, which is much MUCH larger than falcon, meaning fewer launches to expand the network and more users per satellite, more fuel per satellite which extends the lifespan, etc.
DaoFerret t1_j9sanh7 wrote
Starship also opens up orbital recovery/refueling as a possibility, both of which would also jiggle the equation around.
CMDR_Shazbot t1_j9sfwb3 wrote
Ya that would be insanely interesting to be able to go up and just...scoop whole sats for refurb and return. Calculating the conjunction, the entire landing leg with enough-but-not-too-much fuel with the added mass, and securing it in the vehicle to survive re-orbit wold be... challenging.
mdielmann t1_j9rbzj0 wrote
23 × 1.2 tonnes is 27.6 tonnes of debris. To convert to tons, multiply by 1.1, giving about 30.4 tons. (Remember, a tonne is 1000 kg, and a ton is 2000 lbs. Don't mix those numbers up.) So, it's more like a 65% increase daily, which may be no laughing matter, depending on what those compounds are. But first, make sure your facts are correct.
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