Space Junk Getting Worse 242
HockeyPuck writes "According to Space.com the amount of space junk is getting worse. 'A head-on collision was averted between a spent upper stage from a Chinese rocket and the European Space Agency's (ESA) huge Envisat Earth remote-sensing spacecraft. [...] But what if the two objects had tangled? Such a space collision would have caused mayhem in the heavens, adding clutter to an orbit altitude where there are big problems already, said Heiner Klinkrad, head of the European Space Agency's Space Debris Office in Darmstadt, Germany."
Re:Push them further away (Score:5, Informative)
I think they normally push them into an orbit that will degrade so that they'll burn up on reentry. That takes less energy than putting them on a trajectory that leaves Earth's orbit.
The real problem is junk that doesn't have working thrusters and communications so that they can tell it to de-orbit.
Re:Push them further away (Score:5, Informative)
When you abandon satellite, fuel tanks or anything else in the space, why not just push it floating further away in space? Let some aliens take care of them.
It takes energy to send a satellite up into a higher orbit, and even more to push it out of Earth orbit entirely...
For that matter it also takes energy to shift a satellite to a lower orbit, too. About the only thing you get for free is atmospheric drag, and then only once your satellite is already low enough to run into the upper atmosphere.
To give a satellite the ability to do any of these things, it must carry its own rocket motors and fuel - this increases the satellite's launch-weight, which in turn increases the fuel requirements of the booster.
Re:Options (Score:4, Informative)
(from http://en.wikipedia.org/wiki/Space_junk [wikipedia.org])
Launch a couple satellites with solid state lasers. Heat up the side of the space junk facing earth and let the laser push it into the atmosphere.
Plus if you have a few dozen up there you could perhaps deflect larger objects, yet they would be useless if you wanted to shoot a target on the surface of the Earth.
There has to be a reason that there has been next to no attempt to control the space junk issue, I guess getting funding to clean up orbits is hard to come by.
How are you going to "push" objects that cross your orbit with 10 km/s?
They have some solutions on wikipedia:
Re:Push them further away (Score:5, Informative)
Really, the big problem with the current space junk comes from orbital bodies that are decades old. Before things were regulated heavily in orbital operations, many satellite were just left to decay and breakup in orbit. As a result, we have a lot of detached thermal blankets and other clutter drifting around up there. There is also a large contribution that comes from nations which do not follow modern disposal regulations. The article mentions that China is one of these nations. There are others (such as Iran) but they are not contributing a whole lot because many space programs are still small.
When it comes down to it, spacecraft disposal is a responsibility just like terrestrial recycling. The responsible thing to do is pay more and dispose of things correctly. Unfortunately, we didn't plan ahead from the get go and some people just prefer cutting corners.
Re:Push them further away (Score:2, Informative)
I think they normally push them into an orbit that will degrade so that they'll burn up on reentry. That takes less energy than putting them on a trajectory that leaves Earth's orbit.
For those lofty orbits in prime real estate (think Geosynchronous), they do push satellites out further into a graveyard orbit. It would take about 1500 m/s deltav to deorbit from way up there, and only a fraction of that to just push it a little further out of the way.
Ablation Cascade (Score:3, Informative)
Re:Push them further away (Score:3, Informative)
Comment removed (Score:4, Informative)
Re:Push them further away (Score:5, Informative)
Correct me if I'm wrong (and I probably am) but don't you GAIN speed as you fall into the sun's gravity well?
Yes, and if we could just set the space junk in space with no momentum, the sun's gravity would be all we need.
But any space junk launched from earth is starting with a solar orbital velocity of ~30km/s. Redirecting a rocket from that orbit into one that intersects the sun takes a lot of energy.
Re:Push them further away (Score:2, Informative)
About the only thing you get for free is atmospheric drag, and then only once your satellite is already low enough to run into the upper atmosphere.
To give a satellite the ability to do any of these things, it must carry its own rocket motors and fuel - this increases the satellite's launch-weight, which in turn increases the fuel requirements of the booster.
Someone correct me if I'm wrong (no, seriously, I'd like to know), but couldn't solar-powered gyroscopic thrust be cheaply incorporated into every launched satellite and be activated once the satellite's mission has expired and the satellite is no longer needed?
Either way, we don't need rockets and fuel to deorbit satellites. We need cheap, reliable, low-mass, devices incorporated into payloads which can create a constant low-thrust for long periods of time. We don't need deorbits to be quick, we just need them to be predictable and fast enough to make way for new launches.
Re:Push them further away (Score:3, Informative)
Someone correct me if I'm wrong (no, seriously, I'd like to know), but couldn't solar-powered gyroscopic thrust be cheaply incorporated into every launched satellite and be activated once the satellite's mission has expired and the satellite is no longer needed?
"gyroscopic thrust"???
Gyros can be used to *rotate* an object in orbit, but unless they rewrote the laws of physics since I went to school there's no way to get "thrust" out of one.
Re:Push them further away (Score:3, Informative)
Unless it takes up zero volume and zero mass, then it's not free.
On top of which, the claim that it 'exists' is a shaky one, as while tethers are theoretically simple they've proven very hard to implement in practice. They're a long way from being proven technology and ready for prime time. Tethers also have significant drawbacks, the most notable of which is that they can't be used for attitude control.