Big harpoon is 'solution to space junk'

[Judi Lynn]

Jonathan Amos
Science correspondent
@BBCAmos on Twitter
15 March 2018

Airbus is testing a big harpoon to snare rogue or redundant satellites and pull them out of the sky.

The 1m-long projectile would be attached, through a strong tether, to a chase spacecraft.

Once the target was captured and under control, the chase vehicle would then drag its prey down into the atmosphere to burn to destruction.

Airbus has been working on the concept for a number of years now, developing ever bigger systems.

More:
http://www.bbc.com/news/science-environment-43418047

[applegrove]

1. Like a giant squid.

[cos dem]

2. It's not the big satellites that are the problem.

It's the bits that we can't track reliably, but are large enough to cause damage or destruction, that are the biggest threat.
We can move satellites to avoid other big satellites (assuming we know about them. Given the Iridium/Kosmos collision, maybe we don't know as often as we should). Removing defunct satellites is a good idea, but this isn't necessarily a 100% solution.

[Nitram]

6. You are right, cos dem.

We need to trawl space in near earth orbit with a gigantic "net" to gather all the small particles in orbit. Maybe a powerful magnet would do the trick (for pieces that contain iron).

[cos dem]

9. Iron and steel is pretty lousy strength/weight ratio-wise.

So, it doesn't get used in satellite structures very much. You'll find a lot more aluminum, especially honeycomb panels. Also, quite a bit of composite materials, as long as they don't outgas too much.

I'm guessing the best way to deal with these small bits is to blast them with a high power laser. Not necessarily to destroy them, but to get them to deorbit quickly. Needless to say, high power lasers in orbit are a wee bit controversial.

[Nitram]

11. Isn't a laser more likely to burn them up than "push" them out of orbit?

Photons don't have much mass...

[NNadir]

12. A more interesting approach, a little bit near the edge of science fiction, is ion propulsion...

...engines working like truck cabs to ferry spacecraft out of orbit into interplanetary trajectories.

The exhaust of these engines, highly accelerated ions would have the property of either vaporizing small particles or pushing them out of orbit.

One would need to be careful to not put a spacecraft or satellite in the path of this high energy exhaust.

A few ion propulsion engines have already operated in space, but the technology is not mainstream.

Typically - a little oddly from my perspective, they use ionized xenon rather than the more easily ionized cesium.

[cos dem]

14. Actually XIPS is pretty standard on the Boeing 702 bus, which is one of the most popular ...

communication sats.

[NNadir]

15. Well, there you go... These however are most likely small ion engines for small adjustments.

I very much doubt that their exhaust is likely to vaporize anything.

The mass efficiency of an ion engine is related to the accelerations that can be achieved. For removing space debris as a side product of propulsion in Earth Orbit, I'm sure very high accelerations would be required. The higher the acceleration, the lower the mass flux required to move or vaporize a small floating wrench.

For a stupid possibly biologically contaminated Telsa car launched into space by a trivializing publicly subsidized billionaire, of course, very large fluxes and very high accelerations would be necessary.

[cos dem]

13. Vaporizing is actually OK. Vapors aren't a problem, it's particles.

I think the idea is to give it just enough power, applied at the appropriate angle, so that the vaporizing material creates a sort of rocket engine, giving the object just enough negative delta V to get it to deorbit more quickly.

I'm not an expert in this kind of thing, so I don't know if or how well it would work. But it seems at least plausible.

[lapfog_1]

3. another bit of James Bond tech comes to reality

predicted 50 years ago

[FreepFryer]

4. That will work about as well as a harpoon will work to remove ocean plastic.

AFAIK, It’s the multitude of little pieces going 17500mph that U really have to worry about.

[byronius]

7. Re: 'Gravity'.

The depiction in that film was pretty damned sobering.

[FreepFryer]

8. Yup. There's a longer film called 'Space Junk' that goes into detail re risks to human spacetravel.

[cos dem]

10. Do take "Gravity" with a huge grain of salt.

It takes a legitimate concern, and extrapolates it to a ridiculous movie premise. Suffice it to say that almost everything in "Gravity" could not happen in the way it is portrayed.

[msongs]

5. they have some extra a 380's available. nt