Satellites Collide In Orbit 456
DrEnter writes "According to this story on Yahoo, two communications satellites collided in orbit, resulting in two large clouds of debris. The new threat from these debris clouds hasn't been fully determined yet. From the article, 'The collision involved an Iridium commercial satellite, which was launched in 1997, and a Russian satellite launched in 1993 and believed to be nonfunctioning. Each satellite weighed well over 1,000 pounds.' This is the fifth spacecraft/satellite collision to occur in space, but the other four were all fairly minor by comparison."
When Satellites Collide! (Score:5, Interesting)
A good question.... (Score:4, Interesting)
The question is, did anyone have any specific knowledge of the likelihood of this specific collision prior to the event?
I'm assuming just now there wasn't orbital information of sufficient precision to predict this.
High Perigees LEOs Should be Reserved (Score:4, Interesting)
Low perigee orbits, orbits that dip into upper atmosphere, naturally decay to reentry. If collisions occur, the pieces will naturally decay to reentry.
Rotovators are highly valuable and actually need to operate in LEO to throw things out of LEO, both up and down -- and Rotovators are quite vulnerable to debris.
500 mile perigee is way to high. It is a nighmare orbit for debris proliferation.
Planetes (Score:5, Interesting)
Planetes is a japenese cartoon about this very subject [wikipedia.org], and other unpleasant realities of space travel including space-radiation induced cancer, the birth problems of people living on the moon, and the long delay involved in inter-planetary travel.
The main character, 'Hachimaki', is basically a space garbage collector.
Re:Expanding debris cloud (Score:3, Interesting)
Hopefully the wreckage from this one doesn't end up causing any unpleasant chain reactions. Not only are satellites really expensive, we currently have no especially good way of ridding ourselves of orbital debris.
There is a scifi story by Ken MacLeod where the orbit around earth is filled with so many satellites that when a war erupts and some of them get destroyed, it starts a chain reaction that ends up shredding all the equipment in orbit and creating a high speed debris belt that prevents space travel for several centuries.
I've always wondered if that scenario is realistic, but from a physics point of view it sounds like it could be.
Re:Was this really bound to happen? (Score:5, Interesting)
Typically, when it comes to right of way, the less maneuverable vehicle has the right of way (for example, a balloon has the right of way over a glider, which has the right of way over an airship, which has the right of way over an airplane. Similar rules apply to seaborne vessels.) Taking at face value the summary's statement that the Russian satellite was non-functional, it was clearly the duty of the operators of the Iridium satellite to take action. If you want to talk claims/liability, I'd say that the Iridium folks are on the hook for huge damages--through negligence they've created a massive hazard to navigation that will be a problem for... what, centuries?
Re:5th collision?? (Score:5, Interesting)
Re:Expanding debris cloud (Score:2, Interesting)
There's still no plan in place to clean up the Great Pacific Garbage Patch [wikipedia.org] which is at least an order of magnitude easier than cleaning up all usable orbits. It costs half a billion dollars to launch the space shuttle, how many trips do you think it would take to clean up a huge 3 dimensional space with more surface area than the earth itself?
Re:Obama's first test from Putin? (Score:3, Interesting)
Probably not preventable, the Russian one was inactive so they couldn't communicate with it and I don't know if the Iridium one has any maneuvering capabilities. Furthermore there's only so far in advance you can predict collisions before the random fluctuations become to great. Iridium knew the risk when they put the satellite up their and they have redundancy in their system
Re:Was this really bound to happen? (Score:4, Interesting)
Try fleshing out the analogy so it actually makes sense next time.
Zap it! (Score:2, Interesting)
Ablation Cascade: This is how it starts (Score:5, Interesting)
This is one way the theoretical Ablation Cascade [wikipedia.org] could start. At least then we wouldn't have to worry about getting to the Moon. We couldn't.
Bummer if it happens before the Webb Space Telescope launches...
Re:Metre vs Meter. (Score:2, Interesting)
Risk adjusted net present value (Score:5, Interesting)
So a fair comparison has to compare the economies of a HASTOL rotovator, adjusted for the technological risk, to the difference between current high perigee LEO applications and modification of those applications to have perigees low enough to naturally reenter at about the same time the satellite is at the end of its projected useful life.
The trade-off is not nearly as clear as you make it out to be, and with the value of getting things to and from space being essentially "halfway to anywhere", it is pretty clear that you've got a lot weaker case than you apparently think.
Re:Satellite smoke (Score:1, Interesting)
Should be pretty? I have observed Iridium-33 numerous times. The flares that the iridiums are capable of are very pretty indeed. Awesome is a better word.
Unfortunately, the debris cloud will be probably be far too disbursed to be seen w/o visual aid.
Re:First collision (Score:5, Interesting)
Some of the early proposals for satellite phones would have put enough in orbit that if any two had collided, the rest would have smashed into the debris field, again resulting in a complete block to launch.
Remember, one of the early space shuttles was hit by a fleck of paint in orbit. The impact nearly smashed a hole through the windshield. A fragment the size of a dried pea would not necessarily be visible from ground stations on Earth but might easily be expected to punch through any space vehicle in its path, along with anyone inside.
Re:This was bound to happen. (Score:1, Interesting)
This rule only applies to road. In sea, for example, right of way rules are different: usually the heaviest ship has precedence, 'cos lighter ships are more responsive to evasive maneuver - a heavy freighter doesn't really turn away from an obstacle without some foreplanning.
Similar reasoning could be applied to space: changing directions (requires acceleration and, hence, force) is easier for lighter spaceships. But, of course, the availability of fuel and control is an issue in this case, since reactive rudders don't really work in vacuum.
That said, given the lack of control of space traffic nowadays - thanks to the space race secretism - only the sheer amount of space is protecting us from accidents like that. It makes me wonder: do I need any sort of clearance to launch things into space? If I hit someone, whose fault is it? So far, this has been a diplomatic inter-government issue, but private spacefaring is (fortunately) booming, and some sort of control is gonna be needed.
Of course, no law or international agreement will solve the problem of uncontrolled space junk. This is a rather interesting engineering problem: removing them ain't as simple as removing road obstacles - the amount of energy required is simply too much. If you think aerial navigation is fun, put moving obstacles into the mix. Space Traffic Control can be a bitch sometimes.
Re:First collision (Score:3, Interesting)
I vaguely remember a prediction with accompanying animation that at some point, there would be so many satellites that they would start to collide, creating a chain reaction that would damage or destroy many satellites. In the end you would have a sphere of debris that would make the particular orbit uninhabitable for new satellites. I doubt this will be the result from the current collision, but this is still worth thinking about.
Re:Metre vs Meter. (Score:3, Interesting)
That's why using the European spelling makes it easier to differentiate.
Anyway, I'm pretty sure the SI unit is spelled metre, not meter.
Micrometre [google.com.au] / Micrometer [google.com.au].
Re:First collision (Score:3, Interesting)
The irony will be that all the pollution you are campaigning against will actually cushion the planet from such impacts and any resulting fragment will be no bigger than a chihuahua's head!
Any clean up plans, other than waiting? (Score:1, Interesting)
I have never seen anyone come up with a clean up plan for any of this space junk. We have theories of how to fix every thing from the ozone hole to the gay gene, but I have never seen a single theory on how to get rid of this space junk.
Re:This was bound to happen. (Score:2, Interesting)
This was bound to happen and will happen again. The interesting question is how come they didn't maneuver one of them out of the way. I don't know if 22675 is an active payload that still has power but Iridium33 certainly has the capability of moving. This one was avoidable.
I find it a little suspicious myself. China shows off satellite takedown capability. Not long after that the USA shows off satellite takedown capability. Not long after that a "dead" Russian satellite has an "accident" and takes down a satellite. It may just be that Iridium got a warning and played it too close to save fuel or because an insurance payout would make for a handy cash injection, but the timing and the fact that it involves a satellite from the only superpower not to have demonstrated a satellite takedown capability is quite some coincidence.
Re:Was this really bound to happen? (Score:1, Interesting)
No (well, doubtful - somebody prove me wrong!). Geostationary orbit is about 22000 miles above the earth's surface - over 5.5 times the radius of the earth, and well within the exosphere [wikipedia.org]. This is where there are still technically gas molecules, but collisions between even two molecules are rare.
There is some drag near the lower boundary of the exosphere, which is a few hundred miles up. I work with satellites that fly about 500 miles up, above the lower boundary of the exosphere, and I know that the operational folks occasionally fire the boosters to keep the birds in proper orbit. But I have to believe that at geostationary height, 22k miles into the exosphere, any drag is pretty much no longer a factor. Certainly not enough to cause reentry within our lifetimes.
Anyone more familiar with geo orbits care to comment?
cascade scenario (Score:2, Interesting)
Re:First collision (Score:4, Interesting)
Iridium Flares (Score:3, Interesting)
Re:First collision (Score:3, Interesting)
Totally, utterly wrong. I'm not going to explain it, because you're obviously too self-righteous. Go ask your year 10 science teacher.
News flash: Your year 10 science teach was lying to you.
Just did a bit of digging on wikipedia to confirm the lectures I failed to attend while on my Physics degree :)
There are 4 fundamental forces as follows: Electromagnetic, Strong, Weak and Gravity.
Not sure what this electrostatic force everyone keeps going on about but it is not something I have heard of. Your separation of electromagnetism into separate forces is also incorrect though.
As to deflector shields, before you can discount it entirely you have to decide what you are discounting. What happens to a particle that comes into contact with the field? Is it vaporised or deflected (ie - repelled, anti gravity)
I am not saying they are possible, I am saying they are impossible. What I am saying is that the layman's (ie - you) knowledge of physics is so far away from where modern physics research is so it has become impossible to speculate what is possible from a laymans perspective.
When I studied physics to degree level I was told that the previous years classes were junk so many times I found it frustrating. In the case of Quantum Mechanics and Special Relativity were are getting conflicting views that were only an hour or so apart.
The reason I mentioned gravity above is that it is the fundamental force we experience every day, but are unable to model accurately for more than two bodies of approximately the same mass. In my mind that means we don't know enough about it to discount antigravity being just around the corner. Surely that could be used to produce a deflector shield of some kind although it would be very different to ones we see in the movies as it would act over greater distances and its effects would be far more gradual.
Re:First collision (Score:3, Interesting)
The particle physicist above (The_Wilschon) forgot to clarify one point. The GP was right when he only listed two forces by which matter interacts outside of atoms. Strong and weak nuclear forces do exist, but they pretty much stick to the inside of an atom's nucleus.
Re:First collision (Score:3, Interesting)
not to break into a perfectly good argument, but why not do it this way?
An object does not need to be ferromagnetic to acquire a STATIC charge. Lob a stream of electrons into the debris field, and some of them will stick... to ANYTHING. The objects will develop a static, negative charge.
The objects with their newfound negative charge will now repel each other. The force is not likely to be large, but it does not have to be. The debris field will scatter over time, and even small destabilizations of their orbits will lead to a large divergence in position over successive orbits.
Now on your launch vehicle, you have two options. Maintain a static, negative charge on the nose; this will force further scattering and prevent impact with material within a certain range of relative velocities. Maintain a magnetic field extending in front of the vehicle; this will induce motion in the charged debris, forcing it out of the way. This also has a limit on the maximum relative velocities of the vehicle and the debris.
It may be more effective to use positive ions instead of electrons. In that case, you reverse the charge on the cone. The magnetic method would not require changes. All of this works under the inverse square law, so the force of the effect increases as ship and debris get closer.