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Decluttering low-Earth orbit: It's time to tidy up space
71–80 of 136 posts
Re: Decluttering low-Earth orbit: It's time to tidy up space
#72Kurzgesagt has made a video about space junk.
End of Space – Creating a Prison for Humanity
https://youtube.com/watch?v=yS1ibDImAYU
Re: Decluttering low-Earth orbit: It's time to tidy up space
#73Earlier quoted context omitted.
Infinitesimal over 100,000 years? I'm not losing any sleep over it personally, but that's a long time.
The surface area of the sphere at 1400km is far greater than the earth's surface area. And satellites at that altitude are traveling much slower. Put together, the probabilities would akin to a handful of birds flying on earth, at random altitudes/places/directions, and two of them colliding.
"much slower" is still >7000 m/s
Re: Decluttering low-Earth orbit: It's time to tidy up space
#74Earlier quoted context omitted.
> The real problem isn't that space is getting full of our junk, but that our junk is in a very narrow band of orbits that we use for very specific missions: Sun synchronous polar orbits used by imaging satellites. What's the significance of these orbits?
A sun-synchronous orbit is a polar orbit where the satellite passes over each part of the earth at the same time every day. That is very useful if you want to photograph things at regular intervals using cameras (stable light, no nighttime) or if your satellite uses solar panels as these orbits can be such that the satellite never falls into the earth's shadow.
They still go in to shadow once per orbit typically.
Re: Decluttering low-Earth orbit: It's time to tidy up space
#75Earlier quoted context omitted.
The surface area of the sphere at 1400km is far greater than the earth's surface area. And satellites at that altitude are traveling much slower. Put together, the probabilities would akin to a handful of birds flying on earth, at random altitudes/places/directions, and two of them colliding.
"much slower" is still >7000 m/s
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Re: Decluttering low-Earth orbit: It's time to tidy up space
#76Probably not a HN tier comment, but there's a great anime about space debris cleanup. https://en.wikipedia.org/wiki/Planetes https://www.youtube.com/watch?v=CZ-OyT4ivkM
Also a great manga, some very nice editions are available
Re: Decluttering low-Earth orbit: It's time to tidy up space
#77Earlier quoted context omitted.
This anime is brought up in a lot of threads on space debris, and as others attest is excellent. It's a fully fleshed out and plausible future, where people have jobs cleaning up space debris, and it explores many of the issues that may await that kind of work in the future. Your comment epitomises the golden rule of Hacker News, that you should post "anything that gratifies one's intellectual curiosity".
It was extremely good for its time. For instance, the creators asked scientists to estimate the efficiency of solar panels at the time, and computed the area needed for the space stations they drew. Truly incredible that they went to these lengths. Nonetheless, it is very dated. Fusion power looks a lot worse today than it did back in 2003. The fusion-powered space Jovian exploration ship would be right at home in to…
There was massive amount of in space infrastructure and lots of people. Even though they did space mining there is no way they would be able to put all that in place without RLVs. IIRC they even show them a couple times, basically big NASP like SSTO aerospaceplanes.
They also have regular transcontinental flights going through space, even though its IIRC not clear if its sub orbital ballistic trajectories or FOBS like partial orbit ones.
Still, many would-be hard SF films get this completely wrong - huge space stations and/or interplanetary spaceships yet they launch it all on rather dated looking expandable boosters!
Already The Martian it's pushing is pushing it with using basically improved EELVs (launched by ULA, none the less!) yet having hundreds if not thousands of tons of equipment and propelant in place.
Interstellar or Ad Astra is bad shit insane - dinky ELVs and multiple interplanetary colonization attempts and humongous space ship in the former and KFC & artillery fireballs on the Moon in the former. And Ad Astra even has booster stages being dropped when launching from Mars because hey, why not waste even more resources!
Re: Decluttering low-Earth orbit: It's time to tidy up space
#78Earlier quoted context omitted.
Your father's satellite is very high (1400km, 1000km above the ISS) at the edge of what is classified as low earth orbit. It will be up there for a long while but the chance of it ever hitting anything is infinitesimal.
That makes the very big assumption that the density of other things to hit doesn’t massively increase.
That makes a big assumption we can't remove the junk before the density is high enough
Re: Decluttering low-Earth orbit: It's time to tidy up space
#79Earlier quoted context omitted.
The surface area of the sphere at 1400km is far greater than the earth's surface area. And satellites at that altitude are traveling much slower. Put together, the probabilities would akin to a handful of birds flying on earth, at random altitudes/places/directions, and two of them colliding.
"much slower" is still >7000 m/s
Yes but at that altitude their orbital period is about 1/2 that of low orbits, meaning that even if two orbits do cross paths, there would be fewer potential collisions in a given time. They are 'slower' in relation to size of the sphere they occupy.
Re: Decluttering low-Earth orbit: It's time to tidy up space
#80Probably not a HN tier comment, but there's a great anime about space debris cleanup. https://en.wikipedia.org/wiki/Planetes https://www.youtube.com/watch?v=CZ-OyT4ivkM
Adding couple space related yet quite plausible anime/manga series:
https://en.m.wikipedia.org/wiki/Rocket_Girls - basically space flight marketing for highschoolers created in cooperation with JAXA - has a pretty good description of using a biosuit
https://en.m.wikipedia.org/wiki/Space_Brothers_(manga) - a near future "so you want to be an astronaut, eh? " story - very realistic description of what you need to do before actually going to space (38 volumes/99 anime episodes)
https://en.m.wikipedia.org/wiki/Starship_Operators - a space opera that has quite minimal super science and a lot of hard physics - lasers vs overheating, detection/stealth in space (and the lack thereof), signal propagation issues, how to turn big ships quickly enough to use thrusters/fire axial weapons, using neutrino detectors to spot enemy warships based on neutrinos from their nuclear reactors
Various UC Gundam series - pretty accurate description of O'Neil Island 3 space colonies, mass drivers, orbital infrastructure in general - zero g only ships & stations