I seriously didn't realise there was SO MUCH human created debris up there! http://www.bbc.co.uk/news/science-environment-41973646 7500 tonnes is the estimate, and here's what someone thinks it looks like There's a new machine going up next year, the size of a washingmachine, to practice netting and harpooning the big stuff. Fair enough... cos what you don't want on the International Space Station, is a stone chip in the screen.....it's not covered by your Insurance and it WILL affect your no claims bonus in this case!
That's basically one of the many ideas for clearing up the mess. Launch a craft with a large aerogel "flypaper" and use it to mop up. Bring the craft back down to burn up in the atmosphere. Repeat.
Isn't that the gist of most of the plans... Round up the bigger bits of detritus by whatever means and then bomb it into the atmosphere and/or the ocean [if any of it survives reentry].
True, though with slight variations in technique. I seem to remember that there are also plans to outfit the ISS with high-energy lasers to shoot down pieces should they present a threat to the station. Not sure if anything will come of it though.
I would have thought something like that risked breaking whatever it is you're shooting at into lots of smaller bits. Speaking of space junk and i don't know how true this is but i seem to remember reading that things like satellites get covered in a thin film of human poop left over from Apollo program after a few years in orbit.
As @Corky42 says, you then risk turning a large, easy [ish] to keep tabs on hunk o' space junk in to smaller, harder to track, bits of space junk.
If that's a accurate representation of what it looks like up there then they've sure made a mess. Perhaps we will see a call for “health and safety” inspectors to float around in lower orbit in a not to distant future.
Well, NASA should have a pretty good handle on it, after all they've contributed to most of it, if not all. It's impressive that they are able to track that many objects.
Actually they've been at the forefront of minimising the debris left in orbit for many years. They obviously are responsible for a sizeable proportion of it, but between themselves and the USSR they had a near-monopoly on orbital flight until the late 80s. One of the less likely, but still significant, dangers now (as seen in exaggerated form in "Gravity") is two large objects colliding and fragmenting, forming a cloud of scattered debris which then undergoes more collisions. The biggest problem with getting it all down again is the speed at which it travels - LEO speeds are in excess of 7.8km/s, or 17,500 mph in more approachable units. Two objects orbiting in opposite directions will be very difficult not just to align, but to control in any way.
The 'laser broom' proposal is not a pew-pew Star Wars blaster cannon to blow debris into little bits. The idea is that you ablate the front of any debris to slow it down and lower its orbit, with the Earth's atmosphere taking over once the perigee is low enough. The benefit over a physical catcher is a lower chance of secondary debris: even with an aerogel net, if the relative velocity is high enough there will be plenty of fragmentation and spalling, and that the laser can scale to tackle both tiny debris and larger objects, depending on the capability of the optics to track and focus. Something that has already occurred once with an Iridium and Cosmos satellite hitting each other at a near tangent). Existing debris will slowly decay*, but most of the effort at the moment is dedicated to avoiding adding any more debris. Stages de-orbit themselves, GEO satellites enter 'graveyard orbits', LEO satellites enter controlled re-entries, and there are proposals to mandate 'fail-safe' deorbit mechanisms once these are tested (e.g. particle-sails or electrodynamic tethers that deploy automatically under their own power if main satellite power is interrupted for more than a certain amount of time). With some proposed launch systems using 'distributed lift' (e.g. ULA's ACES, Lockheed Martin's Jupiter tug) this may also add excess in-orbit capacity that can be sold to retrieve and service or dispose of satellites in higher orbits. *Small low objects will decay quickly, larger objects in higher perigee orbits will take longer, but it's the hard-to-track small objects that pose more of a risk over larger but known hazards (reflected in the harsh debris models that required NASA to relax their LOC requirements for Commercial Crew to make passing them actually achievable).
Eventually we're gonna have to lob our sewage out there so may as well get experience first. I've seen Futurama, I know how it goes wrong.
For fear of stating the bleedin-obvious-to-everyone, that is not what it looks like. It it was bits of space debris would typically be 50km or so across. On the one hand 7500 tonnes is a lot, but spread over that large an area one should be careful not to overstate the catastrophic nature of the problem.
But then you have the velocity of the space debris in a near frictionless environment pretty ideal for modelling 100% conservation of momentum... Those things move, they are not motionless. Seems like this image is more aimed at explaining the potential impact of each bit
