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Giant Balloons Could Solve Space Junk Problem
An anonymous reader writes "More than 100,000 objects bigger than a centimeter wide hover around our planet, accounting for 4 million pounds of junk that befouls our atmosphere and threatens the expensive satellites we actually want in orbit. Dr. Kristen Gates, of Global Aerospace Corporation, proposes that we can clear the skies by attaching a football field-sized balloon to dead satellites, which would increase the orbital drag, eventually bringing a satellite down into the atmosphere where it would burn up. The GOLD — or Gossamer Orbit Lowering Device — unit is easily inflated in space, and best of all, if the deployed GOLD balloon collides with space junk, it won't deflate or break the junk into smaller, less manageable bits."
With no pressure on the outside of the balloon it would deflate very slowly. This is doubly so because it does not take much gas to inflate a balloon in space due to the lack of outside pressure.
Easy-peasy. No delta-V issues here...
How can satellites be secret? Either they are highly reflective and everyone can see them or they are going to be very warm.
Naturally the slashdot headline is wrong. They're talking about attaching it to entirely intact satellites to get them to de-orbit without hitting something and making more debris. (as seen from the URL of the story linked: "_Without_Making_The_Problem_Worse"
In other words, you just have to catch up to the satellites.
Also they have developed materials that, once inflated in the vacuum of space, can hold their shape without any internal pressure.
I find it hard to believe that the mass of a football-field-sized balloon is less than the fuel to just drop the orbit into a brief but colourful brush with the atmosphere.
Well you need to factor in the rocket engine, guidance, and the risk that you may lose active control of the vehicle and be unable to deorbit it. My thinking is that a drag brake (or parachute, solar sail or balloon) could be a separate system. Mostly passive. It gets a simple command, or fires on a timer. It orients itself passively and results in re-entry in a couple of months or so.
http://michaelsmith.id.au
If you could find a way to make the exterior sticky as it's being deployed, then anything in a similar orbit and speed would be swept up as well. And I shall call it... The Space-Swiffer!
"No matter where you go, there you probably are." -- Buckaroo Heisenberg
>>>Every gram costs a small fortune, so they used every gram of fuel to keep the satellite "stationary" (i.e. in desired orbit).
It's pretty pathetic that despite 50 years of space experience, we still have to worry about mere grams of fuel. I suspect humans will never develop the ability to travel further than our own solar system - it would be too expensive (in terms of fuel).
1000 years from now we'll be in pathetic shape, with all our oil, uranium, and other resources drained dry, and just barely surviving. Never mind space travel. There won't be enough fuel for the rockets. ----- I also suspect this is why we've never been visited by aliens. They can't escape their own solar system due to lack of energy.
"I disapprove of what you say, but I will defend to the death your right to say it." - historian Evelyn Beatrice Hall
Actually most spacecraft (including "secret" government satellites) are tracked by both governments and private entities. Since the last collision the US Air Force has actually started expanding their capability for this even more. They are very open to working with other parties to solve space debris issues and avoid collisions with their satellites or between other satellites.
It doesn't sound like it's meant to bring down some random spacejunk with which it collides (which would mostly pass through it after all, at best / if impacts won't produce more debris), just to bring down a satellite to which it is attached. Not the only effort of such kind
One that hath name thou can not otter
I'm having a problem understanding how filling low-earth-orbit with Zerg Overlords is a good thing.
Some mornings it's hardly worth chewing through the restraints to get out of bed.
What I don't understand is, since we already paid a hefty price to lift this "material" into space, why not collect it in orbit and save it until we can utilize it as raw materials for future space projects. There must be lots of useful stuff that could be reprocessed and reused.
Doesn't everyone have the expectation that we will have factories in space to build the things that are needed in space from raw materials gathered from around the solar system? This would just be raw materials for those factories that doesn't have to be lifted out of the gravity well of earth.
No Astronauts needed, just one Battery Operated Rubish Gatherer (BORG)
That's all fine and good if you have great attitude (direction) control of your spacecraft. If you lose your gyros or something during the lifetime of the spacecraft, then you wouldn't be able to control an Ikaros like sail. Having a spherical balloon that doesn't care about direction and can inflate with minimal mechanical effort seems a lot more reliable.
It's Dr. Kristin Gates. At least try to get the basic facts right.
The electromagnetic force that is.
Why would you bother with atmospheric drag, just pay out a cable and use electromagnetic drag instead. Oh wait they can do that already...
http://www.technovelgy.com/ct/Science-Fiction-News.asp?NewsNum=264
Ok, now that you have a huge football field sized balloon, why not make the outside surface sticky and collect other bits of space junk on the way to the burn?
A ribbon will actually end up perpendicular to the satellites orbit, due to tidal effects.
Set off a bunch of nukes in the upper atmosphere. This will cause the atmosphere to expand, increasing drag and sending LEO space debris plummeting to earth.
Of course there will be side effects, but hey, it's NUKES.
If this were air, you'd be completely correct. However, in the vacuum of space and with a very light balloon (we're talking on the order of 10lbs for a football-field size one) there isn't much of a moment arm. The force due to drag would probably be measured in ounces and then you have just the weight of the actual structure. Generally when satellites attitude control systems fail, they don't immediately start spinning like crazy, probably just a few degrees per minute.
Why not simply magnetize the dead satellite or include a small permanent magnet? This would create a magnetic sail. The magnetic field around the satellite would slowly trap plasma from the trace of gases and ions in earth orbit, as well as anything leaking from the sat itself. This would inflate the magnetic field lines and expand a kind of mini magnetosphere around the satellite. This would create drag against the earths magnetic field, and outer atmosphere.
Common permanent magnets can be much stronger than needed for this.
http://en.wikipedia.org/wiki/magnetic_sail
After logging in slashdot still does not take you back to the page you were on. It's been that way for 20 years.
Why don't we just do like we always do: Instead of cleaning up the place, move Earth to a less cluttered location in space?
Sandford and Son in Spaaaaaaace?
Impetuous! Homeric!
abelenky17 is off-base. The ones most likely to be of interest are also the largest (and generally most-capable) units, which would require the most fuel to move. Mercury SIGINT satellites are around five tons, and the Lacrosse synthetic aperture radar satellites reportedly mass up to 16 tons, and both are in LEO.
This isn't to say that they cannot change orbits, just that it requires a very good reason to do so, as not only does it use up precious fuel, but like any operational satellite it has scheduled uses. They're never put up there "just in case we need them."
It's also not to say that there is no use for highly-variable orbits. That the Air Force has been playing with their recently-launched toy shows as much. It's just that such things are not trivial achievements. Such capabilities make it much harder to hide from overhead eyes. Lacrosse-5 has some kind of technology that allows it to "disappear" even in direct sunlight, which makes much more sense than loading it with tons of fuel, but still leaves it fairly predictable.
You can never go home again... but I guess you can shop there.
The equation for drag is force = 1/2 * speed^2 * density of atmosphere * area * drag coefficient. At orbital speeds, speed^2 is very large, so even a low density will produce significant drag. Also, the football-field-sized balloon has a very high cross-sectional area in relation to its mass, and even the mass of it plus the satellite, so the force produced will be still more capable of de-orbiting the satellite.
There are no astronauts, there are no robots, there is nothing extra being launched into orbit to intercept existing satellites. This is a small, couple kilogram, briefcase sized package that will be attached to new satellites at launch, so at the end of their life, the balloon will be deployed, and the satellite will de-orbit in a matter of weeks.
They should have designed these satellites to be self-killing - i.e. Burn a rocket, deorbit, and burn rather than just throw stuff all over the place & forget about it.
Satellites generally are designed to be self killing. All satellites have some sort of moderate delta-v rocket meant for station keeping and orbital maintenance. A significant amount of the fuel for this rocket is held in reserve, in order to de-orbit the satellite at the end of its life. Geosynchronous and other high orbit satellites cannot afford to re-enter, so instead they rise up to a 'graveyard' orbit, in order to keep the useful orbits clean. The purpose of this balloon is to replace the reserve fuel for low earth satellites. It is significantly lighter than the required fuel, so it will allow a higher payload fraction for the satellite.
The big stuff that would be worth mounting a mission to de-orbit typically isn't the problem. The little, tiny, hard to track bits of space rubish is the real problem.
The big stuff can usually be avoided since it is easily tracked. The little, tiny stuff is effectively a bullet travelling at 17,000 or so miles an hour. It's too small to track and one piece of such junk can ruin your spaceship. Plus, there is a lot more of it than the few, big, defunct satellites that you might want to attach a balloon to.
Cheers,
Dave
They that can give up essential liberty to obtain a little temporary safety deserve neither safety nor liberty.
Ben
It's pretty pathetic that despite 50 years of space experience, we still have to worry about mere grams of fuel. I suspect humans will never develop the ability to travel further than our own solar system - it would be too expensive (in terms of fuel).
Travel in space is simple. Ion drives and other forms of electric propulsion have the potential for incredible velocities. Gravitation sling-shotting gives you plenty more velocity for free. The problem is that first 9km/s needed for low earth orbit. You have atmospheric drag to contend with, so you need to get out of the atmosphere as soon as possible.
Consider one of the space shuttle SRBs for example. At full throttle, each is pumping out some 5400kg/s at 2450m/s. That's roughly 16GW, or several times the power output of a large power plant. The only means we have of generating that kind of power is chemical or nuclear, and the general public doesn't much like nuclear powered rockets.
1000 years from now we'll be in pathetic shape, with all our oil, uranium, and other resources drained dry, and just barely surviving.
I'm not sure where you pulled that value from. We've got enough uranium to power us for a hundred thousand years, and enough thorium to run several times beyond that.
They were able to keep #6 in the village so they should be good at collecting the space junk.
One way to stop the little stuff would be to put a BIG piece of aerogel in the orbit(s) you want to clean up. As demonstrated by the space probe Stardust which collected many pieces of cometary/inter planetary/interstellar(!) dust grains at relative velocities of tens of km/sec, it is fully capable of decelerating the particles without disintegrating in the process. (Obviously some orbital debris will be much larger so it would be necessary to make the aerogel much thicker than the 1(?) centimeter thickness that was used.) I don't know how thick it was but looking at the space craft diagrams it looks like a waffle in thickness.
The only reason why this is practical is because aerogels are 99% air (or in this case vacuum). Anything else like styrofoam or for that matter wood would be too heavy to put into orbit economically. Unfortunately, since it can't be compressed, this scheme requires one major new breakthrough, the ability to manufacture it in orbit with almost complete recycling of any additional materials needed. From what I understand, one way to make it is to use supercritical liquid CO2 as a solvent. Well, in order to keep your launch costs down, you'll need to recycle almost every last drop of that.
So perhaps giant panels (spheres?) hundreds of meters (kilometers?) across of aerogels could be used to "sponge" up various orbits. You'll probably need to attach a small ion engine to overcome drag (from the atmosphere and from the junk) as well as to move (slowly) to new orbits of interest (and eventually to de-orbit the whole thing or crash it on the moon!).
I no longer login because I feel that while attacking a company's products is fair game (specifically Apple), having stories singling out their users as "selfish" and unkind is not "news for nerds stuff that matters". Am I an Apple fanboi? Let's just say I've used NIX for decades (yes I'm old) and I'm not talking OS X.