Space Junk Getting Worse

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

[crow]

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

[Tetsujin]

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

[buchner.johannes]

The vast majority of space debris consists of small particles, from microns up to 1 centimetre (0.39 in). Although there are an estimated 100 million such particles in orbit, they represent a tiny fraction of the total mass of human-made objects in space: perhaps 1%. On impact, these particles cause damage similar to that from a micrometeorite and the widespread use of Whipple shields is effective against the damage they would otherwise cause. Many parts of spacecraft, however, cannot be protected with Whipple shields and are subject to constant wear and tear.

As these sorts of smaller debris represent the minority of the mass, and cause little damage, much of the focus on space debris risks centres on larger debris. The exact definition of "larger" generally means "the size that can be tracked using current technology" and thus changes as tracking technologies improve. In general, these objects are on the order of 10 centimetres (3.9 in) or larger and mass from about 1 kilogram (2.2 lb) and up. Collision with a fragment of this size at the average speed of 10 kilometres per second (6.2 mi/s) would be catastrophic. As a result, space missions have to consider a number of operational factors and risk mitigation strategies.

(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:

[edit] Self-removal

It is already an ITU requirement that geostationary satellites be able to remove themselves to a "graveyard orbit" at the end of their lives. It has been demonstrated that the selected orbital areas do not sufficiently protect GEO lanes from debris, although a response has not yet been formulated.[47]

Rocket boosters and some satellites retain enough fuel to allow them to power themselves into a decaying orbit. In cases when a direct (and controlled) de-orbit would require too much fuel, a satellite can also be brought to an orbit where atmospheric drag would cause it to de-orbit after some years. Such a maneuver was successfully performed with the French Spot-1 satellite, bringing its time to atmospheric re-entry down from a projected 200 years to about 15 years by lowering its perigee from 830 km (516 mi) to about 550 km (342 mi).[111]

Another proposed solution is to attach an electrodynamic tether to the spacecraft on launch. At the end of their lifetime it is rolled out and slows down the spacecraft.[112] Although tethers of up to 30 km have been successfully deployed in orbit the technology has not yet reached maturity.[33] It has also been proposed that booster stages include a sail-like attachment to the same end.[113]
[edit] External removal

The vast majority of space debris, especially smaller debris, cannot be removed under its own power. A variety of proposals have been made to directly remove such material from orbit. One of the most widely discussed solutions is the laser broom, which uses a powerful ground-based laser to ablate the front surface off known debris and thereby produce a working mass that slows the debris in orbit. With a continued application of such thrust, the debris will eventually spiral down into a low orbit and become subject to atmospheric drag.[114]

The US Air Force worked on a ground-based design under the name "Project Orion".[115] Although a testbed device was slated to launch on a 2003 Space Shuttle, numerous

Re:Push them further away

[BJ_Covert_Action]

These days, for the most part, we do that. Launch trajectories are planned with CCAM (collision and contamination avoidance maneuvers) deorbit profiles or extended orbital profiles. That is to say, spent rocket stages and such tend to be rocketed into escape orbits or back into the atmosphere to breakup. Satellites are a bit harder to do this with, as, sometimes they end up using a bit more fuel than planned and, as such, may not be able to thrust into a proper disposal method. Of course, this is also regulated now so most (if not all) modern missions are required to take this excess fuel margin into account when being designed.

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

[tbischel]

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

[PseudoThink]

aka. http://en.wikipedia.org/wiki/Kessler_syndrome [wikipedia.org]

Re:Push them further away

[WindBourne]

The majority of junk is from garbage breaking off from the separations, etc. The issues are not the old sats as many have been moved. The real issues are the SMALL ONES (size of nuts, screws, etc) that can come in at 30K mph (retrograde) and take out the ISS or a craft. Another biggie was China's recent anti-sat work. When they destroyed the weather sat, they sent LOADS of small scrape EVERYWHERE.

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[account_deleted]

Comment removed based on user account deletion

Re:Push them further away

[Chris Burke]

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

[Temujin_12]

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

[Lloyd_Bryant]

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

[DerekLyons]

Actually, a rocket motor and fuel is not required. A cheap, easy, and--I hate to use this word, but--"free" form of orbital propulsion exists. Electrodynamic tether propulsion [wikipedia.org].

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.