121–130 of 136 posts
When I worked in insurance I'd often discuss satellite debris with our Head of Space. I'd always be told, this isn't something to worry about, since she makes bets on this stuff for a living (admittedly with other peoples money) I'll assume she's right.
Genuinely curious: the insurance industry worries about space?
@dang, I thought paywalled articles weren't allowed.
> It's ok to post stories from sites with paywalls that have workarounds.
> In comments, it's ok to ask how to read an article and to help other users do so. But please don't post complaints about paywalls. Those are off topic.
I can read the article fine, so I presume there's some level of free access before you trigger the paywall.
Fun fact: A hobby satellite my father helped build as a way to justify procrastinating during university in the late 60s is now low Earth orbit space junk. He says he's rather embarrassed to have learned, post launch, that it would likely remain in orbit for 100,000 years. https://en.wikipedia.org/wiki/Australis-OSCAR_5 http://centralblue.williamsfoundation.org.au/oscar-5-the-fir... https://www.youtube.com/watch?v=hj…
> Launch date: 23 January 1970 Phew, 23 days earlier your father would have had to code all timestamps in negative. Joke apart, which OS did such satellites run? Unix? Probably not, since timestamps only started in 1970. Just "C"? Even today, how do you register time on satellites? With Unix timestamps (a long since 1970-01-01)? Can they synchronize based on objective points (stars or Earth position to the sun) or ar…
Star trackers give you location in orbit and orientation of your satellite. I don't believe you can get absolute time from them, especially given that Earth time is somewhat decoupled from Earth's orbital dynamics.
What you can do is get time using GPS, like you would on the ground. Not sure if that's possible for higher orbits, but definitely for low orbits. There have also been some experiments with laser-based synchronization (a PPS-style signal, I believe?) and you could get a coarse sync with a regular old radio uplink.
Fun fact: A hobby satellite my father helped build as a way to justify procrastinating during university in the late 60s is now low Earth orbit space junk. He says he's rather embarrassed to have learned, post launch, that it would likely remain in orbit for 100,000 years. https://en.wikipedia.org/wiki/Australis-OSCAR_5 http://centralblue.williamsfoundation.org.au/oscar-5-the-fir... https://www.youtube.com/watch?v=hj…
And here it is! http://stuffin.space/?intldes=1970-008B
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They still go in to shadow once per orbit typically.
A dawn-to-dusk sun-synchronous orbit completes most of its orbits in full view of the sun: > This means that, for most of the year, PROBA2 will have a full-time view of the sun, and will not experience eclipses of the sun behind the earth. However, because the orbit does not follow the terminator exactly, PROBA2 will experience brief periods of several weeks when eclipses of the sun by the earth do occur, specificall…
Thanks for sharing this use use case too though, pretty neat.
Fun fact: A hobby satellite my father helped build as a way to justify procrastinating during university in the late 60s is now low Earth orbit space junk. He says he's rather embarrassed to have learned, post launch, that it would likely remain in orbit for 100,000 years. https://en.wikipedia.org/wiki/Australis-OSCAR_5 http://centralblue.williamsfoundation.org.au/oscar-5-the-fir... https://www.youtube.com/watch?v=hj…
And here it is! http://stuffin.space/?intldes=1970-008B
CO2 / plastic.
When the society is mature enough to clean the mess created ?
P.S. Sorry for offtopic rant
Earlier quoted context omitted.
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.
90 mins at 400km vs 110 mins at 1400km
Edit: I just looked up the formula for orbital period and it turns out period is proportional to radius^(3/2) (See: https://en.m.wikipedia.org/wiki/Orbital_period)
curious of the price of de-orbiting an m6 screw (say m = 4g, v = 8000m/s) given it has the same kinetic energy as a small car (m = 1000kg v = 16m/s).
You don't need to get rid of all those 8km/s. Just enough to drop down into the atmosphere, the rest is a shooting star.
Earlier 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.
It's only about 50% larger (1+1400/6371)^2 = 1.49
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I think the concern is that despite increased activity in space, most countries have slowed down the amount of dangerous debris being created. Meanwhile, India created about as much space junk in a day as the US creates in 1-2 years. That's despite claiming that the the test was in an orbit that wouldn't leave any longterm debris.
I think you should focus on the huge amount of garbage and carbon emissions produced everyday in the USA (biggest contributor to climate change), which is objectively a much bigger problem than this one-off event which media portrayed as some sort of catastrophe. It's "glass houses" all over again. Why should a nation of 350M people have ASAT capability in the interest of national security, but not a nation of 1.4B p…