On the Matter of Space Junk

SpaceAdmiral writes "Nature reports that space is in need of cleaning. From the article: 'Space could soon become too risky to visit unless derelict satellites and rockets are removed from orbit. That's the stark warning from a new simulation of space junk drifting around the Earth, and scientists are calling for swift international action to solve the problem.'" According to another astronaut there is at least one more piece of space trash they haven't accounted for. Philip K Dickhead writes "Veteran astronaut Mike Mullane claimed that the NASA Space Shuttle is 'the most dangerous manned spacecraft ever flown [...] It has no powered-flight escape system." He also accused US space officials of suppressing safety concerns raised by crew-members of shuttle flights."

Comments

satellites and Starry Night software

[calyxa]

I have Starry Night, a night sky simulator, and I was amazed at what things looked like when I set my location to the north pole and sped up time by 300x. There were dozens of satellites zooming overhead constantly!

Re:satellites and Starry Night software

[mkosmo]

I use Orbiter ( http://orbit.medphys.ucl.ac.uk/ ) as my space flight simulator. Too bad it doesnt feature space junk :) They also accurately represent space objects as you add them, and its amazing... despite there being so much area... i thought I was too close within 10000 miles of anything. Then again, at those speeds, that is close. Space flight is tricky, and the shuttle does need some escape, but also, we do need to clean our trash out there as we do here. It will be a sad day when space is as full as your local landfill...

Make the corporations responsible..

[QuantumG]

For a start, rewrite the space treaty so governments are not responsible for everything their citizens launch into space. Next, hold the corporations responsible for their own mess. For every year they fail to deorbit their space junk (or boost it into a safe parking orbit) charge them a fine. If the fine is just twice as high as a terminator tether they'll soon take care of their space junk.

Re:Make the corporations responsible..

[lazybratsche]

This might be a step in the right direction, but it only addresses the problem of big peices of debris (i.e. whole satallites or components).

What sounds like the bigger problem is all the tiny hard to track fragments, the sort of stuff created when stages of a rocket seperate explosively. Here, perhaps, more work could be done in developing rockets and satellites that don't shed this sort of garbage.

Re:Make the corporations responsible..

[DerekLyons]

What sounds like the bigger problem is all the tiny hard to track fragments, the sort of stuff created when stages of a rocket seperate explosively. Here, perhaps, more work could be done in developing rockets and satellites that don't shed this sort of garbage.

Well, welcome to 2006 - where not shedding debris has been the gold standard for a decade and more. Contrary to the TFA, the problem *is* being adressed. Among other things, every major rocket manufacturer has modified stages of theirs that will be left in orbit to depressurize themselves at the end of the burn - no pressure, no breakup. Every major rocket manufacturer has replaced their seperation systems with ones that don't shed parts.

Ken MacLeods Books

[MishgoDog]

Ken MacLeod's Sky Road presents a scenario space is so cluttered part of the premise of the book is that an AI is required to navigate it - no human could leave Earth because of the chaos up there. Lets hope it doesn't get that far!

Sounds like we need the Debris Section!

[EvilMagnus]

Planetes deals with exactly this problem. Only they didn't see it as being an issue until the 2070s (the series takes place in 2075).

Still, a pretty fun anime, and the manga is even better.

new moon

[j1m 5n0w]

Maybe if we gathered them in one place we could eventually have a new (very small) moon that could be easily tracked and avoided. I suppose it would be below the roche limit, and would thus perhaps need to be caught in a net, or a strong magnet.

Anyone care to guess which would require more delta v, deorbiting a satelite or moving it to a "designated rubbish pile"? It seems like some space debris would be salvageable, it seems a shame to drop it back into the atmosphere after spending so much fuel to get it up there in the first place.

Anyone have any good ideas for the names of aforementioned moons?

With the recycling!

[Gorimek]

It gets real useful when you then build a space station out of all that "trash". It's not perfect, but given that it costs $10k/kg to send up cusom made stuff, you should be able to do a lot, given the right tools.

Re:With the recycling!

[cbcanb]

Trust me, it's much cheaper just launching new stuff at $10k/kg than to bodge together something using the junk already there.

It's called "space junk" for a reason. Some of it's probably OK, but most of it is real garbage.

motivation

[bcrowell]

I'd be much more motivated to clean up my garage if I had to move through it constantly, while the junk was all whizzing by at relative velocities of thousands of miles an hour.

Re:motivation

[Bad D.N.A.]

Really?

Even if it cost you like a gazzilion dollars to clean your garage with only a miniscule chance you would ever come in contact with the hypersonic junk, and then only a miniscule fraction of those times it would pose an actual problem?

That would be one seriously expensive spring cleaning

OK

[hurfy]

'the most dangerous manned spacecraft ever flown '

As opposed to the ones that have a powered ejection seat...

Surely you cant eject gracefully from that little Russian capsule either, or can you?

So the LEAST dangerous one would be ???

or does he simply work for a aerospace design corp now?

WOuld be handy i suppose IF you were in the right time of launch to use it and IF you had time to activate and IF you were pointed the right way (wouldn't really want to eject toward the path of a booster rocket or something).

Exactly how long does one have when the bomb you are riding on goes off? Didnt the first one blow up almost immediately?
Certainly you cant eject during reentry, if your ship is burning up, isnt that jumping out of the frying pan and into the fire?!?

Re:OK

[Dun Malg]

Exactly how long does one have when the bomb you are riding on goes off? Didnt the first one blow up almost immediately?

The Challenger crew compartment was essentially still one piece when it hit the ocean. Considering that part crew escape mechanism design involves engineering decisions like NOT putting the crew vehicle next to the "bomb" , like the space shuttle, but rather putting it on top, like [soyuz|apollo|other traditional] spacecraft; well, yeah, then there's plenty of time for a solid fuel rocket to separate them from the fireball.

Certainly you cant eject during reentry, if your ship is burning up, isnt that jumping out of the frying pan and into the fire?!?

The space shuttle is a flimsy design, 30 years out of date. "Standard" spacecraft design is pretty darn reliable-- they basically don't burn up on reentry because they're not built out of ceramic foam blocks glued onto superlight carbon fiber frames, they have predictable non-flimly ablative heat shields. The only time you'd ever need to "bail out" with a standard design would be if the parachute failed, after actual reentry, and that is (in theory) possible.

So basically the two space shuttle accidents have shown that it is a highly vulnerable system. A fuel tank explosion on launch of (say) one of the Apollo/Saturn V launches would result in the crew module separating and being pulled away by the solid fuel rockets of the escape tower for a safe parachute landing. Damage to the reentry vehicle from an insulating foam chunk off the launch vehicle would be impossible, given that A) the former is above the latter, B) it's not built like french racing bicycle out of delicate materials, but more like a solid military aircraft.

Re:OK

[Dun Malg]

... Russian capsules after reentry. They use high explosives to cushion the landings

They use solid-fueld braking rockets for last-second deceleration of a parachute landing. Rocket failure might result in some pretty nasty bumps and bruises, but that's all. It's a highly reliable system. The soviets even used it for para-dropping armored vehicles with the crew strapped inside. NASA opted for "splashdown" and naval recovery for simplicity's sake.

Re:OK

[WegianWarrior]

As opposed to the ones that have a powered ejection seat...

As opposed to the ones that have any form of escapesystem at all. The Gemini and the Vostok used ejection seats (the use of which was the normal mode of ladning in the case of the Vostok - the cosmonaut did not ride his capsule all the way down). The majority of manned spacecrafts (Mercury, all the various versions of the Soyuz, Apollo, Shenzhou and the planned CEV) fetures escape towers - a rocket that will pull the part of the spacecraft with people inside away from any accidents (and hopefully high enought up for parachutes to work). As far as I can tell, the Shuttle shares the dubious distinction to be one of two (the other was Voskhod, which was basicly a juryrigged Vostok) to have flown in space with no escapesystem at all.

Back in the 'good, old days', a lot of thought went into weird and wonderfull ways to bail out from orbit, but these days it seems like there is little will to admidt that things can go horrible wrong up there...

Re:If we can't clean up junk, forget other NEOs.

[Jerf]

Big number fallacy; a nuke is big, sure, but let's be amazingly optimistic and assume it can completely physically clear a 10-mile radius of space junk, while not adding anything itself.

The average radius of the Earth is 3,959 miles, call it 4000. The definition of LEO orbit is from 400 to 1600 miles above the Earth. Sphere volume (close enough) is defined as (4/3)*pi*r^3.

To cover LEO, we need to cover a volume of (4.0/3)*pi*((4000+1600)**3 - (4000+400)**3) miles, which is 378,000,000,000 cubic miles (378 American billion). Our incredible optimistic nuke can "clean" (4.0/3)*pi*(10 **3) cubic miles, or 4,200 cubic miles. Dividing the (unrounded) numbers reveals that we need to set off 90,449,062 (~90 million) miracle nukes to clean the orbit.

(If you start python and type as your first line "from math import pi", those expressions will slide right into Python so you can verify them. Insignificant figures have been trimmed for presentation.)

And it's even harder than that, since the objects are moving at different speeds, and it's quite easy for objects to slip between the cracks if we don't light up the entire orbit at once.

Clearly, this is absurd, because we don't even have that many pieces of space trash in orbit, by many orders of magnitude. Because of the difference, we don't even need to do any sort of statistics to safely conclude that there are no "concentrations" of space trash that could be nuked, and we are in fact going to have to address the situation one piece of trash at a time.

various uses for space junk

[j1m 5n0w]

Trust me, it's much cheaper just launching new stuff at $10k/kg than to bodge together something using the junk already there.

It's called "space junk" for a reason. Some of it's probably OK, but most of it is real garbage.

I suppose that depends on the intended purpose. I don't think assembling a space station out of it is practical (at least, not without a lot of manufacturing infrastructure that we don't have in orbit right now), however, it could be used as part of a space elevator counterweight (assuming the significant orbit modification can be made more cheaply than launching a similarly heavy object from the ground), or use the debris as the reaction mass for a mass driver, or use it as a radiation shield.

deposit?

[j1m 5n0w]

Perhaps the solution would be to require companies to put down a deposit whenever they stick something in orbit. They get it back when the object leaves orbit.

Re:Quick clean

[Skeezix]

I think we need a vacuum in space. Oh, wait...

Re:If we can't clean up junk, forget other NEOs.

[Phil Karn]

Your professor almost certainly was talking about a series of US "high altitude" (i.e., space) nuclear weapons tests performed in 1958 and in 1962. This was at the very beginning of the "space age", so while the radiation effects on the few satellites in orbit were very significant (or fatal in some cases) there weren't many of them up there to be destroyed.

You can find good writeups in any good history of US nuclear testing. The Wikipedia article on "Nuclear testing" is as good a place to start as any. Look for "Rocket-propelled warheads".

This sort of thing was banned by the Limited Test Ban Treaty, signed by the US and USSR in 1963.

Chain reaction..

[aero2600-5]

You would think the potential loss of almost all the satellites in orbit would make them do something about this. The junk floating around in our orbit is a disaster waiting to happen. The satellite traffic is already pretty heavy. Assume that one of the satellites suffers a direct hit from a meteor or a fast moving piece of space junk. You're satellite has just become about 100 pieces of space junk. Assume that just two of those pieces collide with other satellites. Now there are a couple hundred pieces of space junk in that particular orbit. Follow the chain reaction, and we could lose most of our satellites in just a few weeks.

We're going to wind up with rings just like Saturn, but ours is going to be the remains of our communications infrastructure.

Aero

Time for Quark!

[1_brown_mouse]

Quark (1977) or Quark (1978) was a great show where Adam Quark, captain of a United Galactic Sanitation Patrol ship, and crew collected giant space baggies of trash.

What was old is new and in humour there is truth.

less delta-v?

[lilmouse]

Anyone care to guess which would require more delta v, deorbiting a satelite or moving it to a "designated rubbish pile"?

I'll take a guess and say deorbiting is cheaper.

Why? Because you can you use very basic, very slow ways to brake it's orbit - such as painting it the right colour so that it will reflect sunlight and get pushed closer to the earth. (Think of plans to move that asteriod that might his us in 70 years) We don't have to deorbit it *now*, just eventually.

I can see the argument about keeping it out of the gravity well, tho :) If we could just dump it on the moon...

--LWM