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Astronauts eject UK-led space junk demo mission
A UK-led project to showcase methods to tackle space junk has just been pushed out of the International Space Station.
The RemoveDebris satellite was ejected a short while ago with the help of a robotic arm.
The 100kg craft, built in Guildford, has a net and a harpoon.
These are just two of the multiple ideas currently being considered to snare rogue hardware, some 7,500 tonnes of which is now said to be circling the planet.
Previously: SpaceX Launches CRS-14 Resupply Mission to the ISS
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Space Junk Removal Testing Craft Ejected From the ISS
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The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
Oh, that sound of male ego. You travel halfway across the galaxy and
it's still the same song.
-- Eve McHuron, "Mudd's Women", stardate 1330.1
(Score: 2) by ledow on Friday June 22 2018, @05:48PM (2 children)
Gosh, what would I call a spy sat that I didn't want people looking at? If only I could call it, say, a failed launch that remained in orbit but ended up "unpowered" (very common).
Your sweeper sat comes along, trashes the Russian sat thinking it's junk, bang you've just started a war.
Either:
- Someone owns that debris, and will give you permission, if you can trace that person
- Nobody knows who owns it (because if we know who owned every piece of space junk, we wouldn't have to track it, would we?)
An orbit is a hard thing to achieve in perfection (proven by the REAL failed missions). While things stay in their orbits, you're fine. They're not space junk. They're orbiting in the right bands. But space junk will collide with anything, and move, and then end up in an elliptical orbit and now you're buggered - it could end up anywhere, crossing every "safe" orbit out of control and possibly quite unpredictably - it'll also accelerate in angles you didn't intend and become lethal and wide-spread. We've not seen a 10km asteroid in the past, what makes you think we'll see a sat out of line on a non-circular orbit?
Decelerating the orbit wrong also does exactly what I just said - it doesn't deorbit, or it skims the atmosphere, or it goes eliptical which means it comes back to bite you (faster than ever intended on it's longest path) on a different timescale to that which ANYONE intended. Do you not remember how slim the Apollo 13 margins were to enter the correct orbit-exit trajectory? It's a damn miracle they could do it at all.
It's not that it's not possible - it's that it's not as easy as you make out. And needs power, control and time to get it right. Luxuries you don't have in a sat that you're using to deorbit things. Either it's a one-time deal at HUGE expense, or that device has to be able to suck up a TON of propulsion power to do such maneouvures.
Things that are circling nicely in prescribed orbits occupying regulated bands of space, that kind of space junk is never a problem because it's easy to avoid, and there's literally no point clearing it. It's the stuff that's in your way, unpowered, failed orbits, unusual orbits, random, unregulated, uncontrolled, unpredictable and untrackable that's the problem
(Score: 2) by frojack on Friday June 22 2018, @07:47PM
You realize that this has actually happened already and there was no war, right?
https://www.space.com/20138-russian-satellite-chinese-space-junk.html [space.com]
https://www.huffingtonpost.com/entry/the-worst-collision-of-orbiting-satellites-and-space_us_59406ffee4b04c03fa26166e [huffingtonpost.com]
No, you are mistaken. I've always had this sig.
(Score: 2) by Immerman on Friday June 22 2018, @07:48PM
First off, "space junk" is generally used to refer to the debris created by previous collisions (and dropped wrenches, etc.), small enough to be difficult to track - intact satellites are easily tracked navigation hazards.
Destroying something you publicly called trash has got to be one of the least-compelling reasons to go to war I've ever heard. It's not going to be a *reason* to go to war - at best it will be a really bad excuse. And of course we have to track space junk even if we know who "owns" it since, as you pointed out, there's no such thing as a stable orbit.
Any de-orbit attempt that skims the atmosphere is successful, though it may take several more passes to complete than planned, since every subsequent orbit will also skim the atmosphere.
As for Apollo 13 - the orbit-exit in question was NOT to de-orbit, but rather to boost out of lunar orbit on a trajectory that would carry it across the it 239,000 miles to just skim the 8,000-mile diameter target of the Earth on a path that would allow for orbital braking and reentry without killing the crew. A *far* more difficult thing to do than simply de-orbit junk that you want to have burn up in the atmosphere. De-orbitting is easy - just fire your rocket directly against your line of motion, to impart enough delta-v to lower the opposite side of the orbit into the Earth's atmosphere. For safety you can impart too much delta-v so that you take a more direct route to collision with Earth - only a problem if deorbitting something large and durable enough to have a fair chance of reaching the ground if it comes in at a steep angle.