Kligat writes "For the first time since 2003, the International Space Station has utilized the rockets on the European Space Agency's Automated Transfer Vehicle to dodge leftover remnants of a defunct satellite. The Russian Cosmos-2421 was launched in June 2006 to track Western Navy vessels and is believed by NASA to have exploded — 'likely due to a self-destruct command issued by Russian officials' according to the article — leaving 500 pieces of space debris. Ordinarily, the rockets on the ATV are used to take the ISS away from Earth's atmosphere and reduce drag. In this case, the 5-minute firing caused the ISS to move downward because it was already near the top of its acceptable range. Estimated probability of impact was 1 in 72, and an avoidance maneuver is called for if the probability is greater than 1 in 10,000. The space junk was predicted to pass the ISS within just a mile."
while it seems like a waste cause the rocket fuel was used to cancel out a previous boost maneuver, keep in mind that the ISS needs to be within a certain altitude band to be reachable by the soyuz/shuttle. also, the humans on board necessitate resupply missions more often than boost manuevers are required anyway.
Actually, this really sucks because the rockets were used to LOWER the ISS. What a waste. I wonder how much warning they get before estimated impact.
Actually, they were planning to lower the ISS for the next few missions anyway so that the shuttle would be able to bring up more cargo than usual. This maneuver wasn't so much a waste as it would seem to be.
Pure case of state-controled media going on in Russia. They're not willing to admit they had a spy satellite in the first place, so they're not able to explain where the debris came from. That turns out to be something NASA is more than willing to do for the American side.
NASA doesn't have any spy satellites. The Defense Department does. I wouldn't be surprised if there are a few fields of debris from US spy satellites that haven't been announced or anything. Such information is somewhat sensitive, and official denial may be important. Could be anything from 'protect the existence the other spy satellites in its family' to 'let's save face'. To be fair, I could totally see your DoD doing something similar.
The problem with this theory is that there are about 100,000 geeks in the world that love nothing more than to tag every single man made object in space. They even have programs to show every bit in real time graphically orbiting the planet. Many of these are free for download.
You can't put or have anything in space bigger than a small stone and not have some government or organization find and tag it, only to release that data to the general public at some point not very long after that. Lots of RADAR being pumped out in to space just for this very purpose.
If the ISS was moving because of anything other than debris from a Russian spy sat, then the slashdot headline here would spell it out. Even the military make use of the work from these guys, it can sometimes actually be more up to date.
Me: Ex 3 letter agency drone that worked in the satellite area for a while.
The orbital trajectory of every piece of debris from a spy satellite that was intentionally blown up isn't so well known, especially when the nation controlling the satellite wants it to be a secret.
While that's a valid point for some situations, radar systems tend to have problems tracking objects below a certain size. A marble moving at 36,000 miles an hour isn't likely to be picked up by any radar array that I've ever seen.
The other problem is that they suck up a lot of juice. An active radar dish blaring away 24/7 would be a significant drain on the electrical power available to the ISS. I can't say it's not possible since I don't know how much their solar arrays can generate, but I'm willing to wager that it'd be a problem.
Add to what you said that if the debris is traveling at a high speed WRT the ISS, even if it could be detected by radar there wouldn't be a whole lot of time to do anything about it.
At the risk of being redundant, it's roughly a 1 in 72 chance that their calculations of a "miss" are off. Calculations of this sort involve a margin of error, from not precisely knowing locations of these objects to not being able to do forecasting accurately enough. Debris A gets hit by debris B (which somehow evaded your radar), sending off two new chunks of metal which weren't even IN your original calculations. I'm actually impressed that they can put solid numbers on these things, but I guess that's what supercomputers are for.
this post made me wonder. could they repurpose the nautilus anti missle laser system to knock the space junk that threatens the station out of the vacum of space. Or could it make things worse? (lots of tiny particles you can't avoid vs. a couple of big particles.
Cooling might be a problem. If your laser is powerful enough to vaporize a couple tons of debris, and transfer enough kinetic energy to change their orbit so they no longer intersect, its going to generate a good deal of heat. Maybe the ISS's current radiator can't handle it. Firing rockets is easier cause you get to dump all a lot of waste heat into your reaction mass and throw it into the void.
Time to call the Space Debris Section of Technora Corporation....
I wonder how far something like Planetes is off from reality at times. Excellent series.
GrpA
They should attach large electromagnets to the ISS and collect all of the space junk it passes by for recycling. I wonder what payment the recycling depot would give for satellite parts. I don't keep track of shuttle payloads, but I would imagine that there would be room for a satellite or two in the cargo bay on the return trip.
All kidding aside, the value of a pound of aluminum in LEO has to be thousands of dollars... I wonder if someday it might make sense for a larger, commercial space station to try to capture any random piece of matter that crosses its orbit, just for raw materials.
That's a heck of a close call, considering the ISS is traveling at 4.8 miles per second. That's little like a car at highway speed running a red light and missing another car by less than one car length.
That's a heck of a close call, considering the ISS is traveling at 4.8 miles per second. That's little like a car at highway speed running a red light and missing another car by less than one car length.
Not really, since their relative speeds may be far less. If the debris cloud is traveling on the same trajectory at 4.7 miles per second, then their relative velocity is only 360 miles per hour.
On the other hand, if it's traveling on the exact opposite trajectory at the same speed.... ouch.
Here's a graph of ISS altitude [heavens-above.com] for the last year, if anyone is interested in hard data. (The steady downward slope is due to atmospheric drag, and the sharp increases are from firing maneuvering thrusters to maintain altitude. Presumably, the recent abrupt drop was the maneuver described in the article.)
Anyone here know how they calculate "impact probability" ? I mean, my poor man's logic seems to think you either hit something, or you don't. Bool 1, or Bool 0.
If you miss something by a mile, how does that wind up being a 1 in 72 probability ? No offense to the space buffs, of which I am not one, but that sounds like game show odds to me: "You're bound to lose, but let's all act excited anyway!"
The calculated miss distance was about a mile, but there was uncertainty in that miss distance such that there was a 1 in 72 chance it wouldn't miss the ISS, but instead hit it directly.
To answer your question (at a high level), the sensors and models that are used to track and predict the debris locations have associated mathematical models that can put a number on the uncertainty of where that debris is. The uncertainty takes into account things like how many radar obs were made, the inherent accuracy of
by Anonymous Coward
on Monday September 01 2008, @06:09PM (#24835887)
I'm not a rocket scientist. Is there another kind of drag that needs to be reduced?
The drag of being stuck in a space station! It's pretty much like being in prison, but when you stick some rockets on it, suddenly you feel like a supervillain!
Depends on the error ellipse of the orbit determination for the junk, and it sounds like the uncertainty is a good fraction of a mile in size. But in any case, the miss distance is a mile after the course adjustment, not before.
I was actually thinking about ordering it just yesterday. I haven't seen it, but it seemed to get good reviews on Amazon, and sounded like the science was pretty sound.
The central ISS modules (Zarya, Zvezda) are Russian. Actually, the docking port the ATV is using is also Russian, using the "probe and drogue" technique. I would call their contribution quite remarkable.
In SOVIET RUSSIA.. (Score:5, Funny)
You watch out for spy satellites!
Re: (Score:2)
Actually, this really sucks because the rockets were used to LOWER the ISS. What a waste. I wonder how much warning they get before estimated impact.
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while it seems like a waste cause the rocket fuel was used to cancel out a previous boost maneuver, keep in mind that the ISS needs to be within a certain altitude band to be reachable by the soyuz/shuttle. also, the humans on board necessitate resupply missions more often than boost manuevers are required anyway.
Re:In SOVIET RUSSIA.. (Score:5, Interesting)
Actually, this really sucks because the rockets were used to LOWER the ISS. What a waste. I wonder how much warning they get before estimated impact.
Actually, they were planning to lower the ISS for the next few missions anyway so that the shuttle would be able to bring up more cargo than usual. This maneuver wasn't so much a waste as it would seem to be.
Parent
Re: (Score:2)
Just like a supermarket (Score:2, Funny)
Russia just can't tell the truth. (Score:2)
Pure case of state-controled media going on in Russia. They're not willing to admit they had a spy satellite in the first place, so they're not able to explain where the debris came from. That turns out to be something NASA is more than willing to do for the American side.
Re:Russia just can't tell the truth. (Score:5, Funny)
Parent
Re: "garbage" (Score:5, Funny)
Parent
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Re:Russia just can't tell the truth. (Score:5, Interesting)
Parent
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I just mentioned that to my Martian friend, and he said "Gzornak frokka wa Hubble, flrckin earthling!"
Re:Russia just can't tell the truth. (Score:5, Interesting)
The problem with this theory is that there are about 100,000 geeks in the world that love nothing more than to tag every single man made object in space. They even have programs to show every bit in real time graphically orbiting the planet. Many of these are free for download.
You can't put or have anything in space bigger than a small stone and not have some government or organization find and tag it, only to release that data to the general public at some point not very long after that. Lots of RADAR being pumped out in to space just for this very purpose.
If the ISS was moving because of anything other than debris from a Russian spy sat, then the slashdot headline here would spell it out. Even the military make use of the work from these guys, it can sometimes actually be more up to date.
Me: Ex 3 letter agency drone that worked in the satellite area for a while.
Parent
A mile? (Score:4, Interesting)
Aren't orbital trajectories pretty well known? How is there a 1 in 72 chance that the thing will make a sudden mile-long jog and hit the station?
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Hmm, good question. I suppose only SchrÃdinger's Cat knows for sure. :-/
Re:A mile? (Score:5, Insightful)
An HTML entity shouldn't be required. It's 2008; we should be able to stick Unicode into these boxes.
Parent
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According to that list [nasa.gov], there are 12 objects with a probability >1/10,000, and 2 with a probability > 1/1000.
Note that the uncertainty on these orbits is frequently many 1000's of km; the orbits of things in LEO are much better determined.
Re:A mile? (Score:5, Insightful)
Because when dealing with the vastness of space a mile is pretty damn close.
Parent
Re:A mile? (Score:5, Informative)
The orbital trajectory of every piece of debris from a spy satellite that was intentionally blown up isn't so well known, especially when the nation controlling the satellite wants it to be a secret.
Parent
Re:A mile? (Score:5, Insightful)
While that's a valid point for some situations, radar systems tend to have problems tracking objects below a certain size. A marble moving at 36,000 miles an hour isn't likely to be picked up by any radar array that I've ever seen.
The other problem is that they suck up a lot of juice. An active radar dish blaring away 24/7 would be a significant drain on the electrical power available to the ISS. I can't say it's not possible since I don't know how much their solar arrays can generate, but I'm willing to wager that it'd be a problem.
Parent
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Add to what you said that if the debris is traveling at a high speed WRT the ISS, even if it could be detected by radar there wouldn't be a whole lot of time to do anything about it.
Re:A mile? (Score:5, Informative)
At the risk of being redundant, it's roughly a 1 in 72 chance that their calculations of a "miss" are off. Calculations of this sort involve a margin of error, from not precisely knowing locations of these objects to not being able to do forecasting accurately enough. Debris A gets hit by debris B (which somehow evaded your radar), sending off two new chunks of metal which weren't even IN your original calculations. I'm actually impressed that they can put solid numbers on these things, but I guess that's what supercomputers are for.
Yay for safety margins.
Parent
it needs friggen lasers (Score:3, Interesting)
this post made me wonder. could they repurpose the nautilus anti missle laser system to knock the space junk that threatens the station out of the vacum of space. Or could it make things worse? (lots of tiny particles you can't avoid vs. a couple of big particles.
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Re: it needs friggen lasers (Score:5, Funny)
Or could it make things worse? (lots of tiny particles you can't avoid vs. a couple of big particles.
well, what we need then is a linux admin who has mastered that Asteroids game
Parent
Bring in the Toy Box. :) (Score:2)
Recycle It! (Score:4, Funny)
They should attach large electromagnets to the ISS and collect all of the space junk it passes by for recycling. I wonder what payment the recycling depot would give for satellite parts.
I don't keep track of shuttle payloads, but I would imagine that there would be room for a satellite or two in the cargo bay on the return trip.
All kidding aside... (Score:2)
Within 1 mile? (Score:4, Informative)
That's a heck of a close call, considering the ISS is traveling at 4.8 miles per second. That's little like a car at highway speed running a red light and missing another car by less than one car length.
Re:Within 1 mile? (Score:4, Interesting)
Not really, since their relative speeds may be far less. If the debris cloud is traveling on the same trajectory at 4.7 miles per second, then their relative velocity is only 360 miles per hour.
On the other hand, if it's traveling on the exact opposite trajectory at the same speed .... ouch.
Parent
ISS altitude graph (Score:5, Informative)
Impact probability ? (Score:2)
Anyone here know how they calculate "impact probability" ? I mean, my poor man's logic seems to think you either hit something, or you don't. Bool 1, or Bool 0.
If you miss something by a mile, how does that wind up being a 1 in 72 probability ? No offense to the space buffs, of which I am not one, but that sounds like game show odds to me: "You're bound to lose, but let's all act excited anyway!"
Re: (Score:3, Informative)
The calculated miss distance was about a mile, but there was uncertainty in that miss distance such that there was a 1 in 72 chance it wouldn't miss the ISS, but instead hit it directly.
To answer your question (at a high level), the sensors and models that are used to track and predict the debris locations have associated mathematical models that can put a number on the uncertainty of where that debris is. The uncertainty takes into account things like how many radar obs were made, the inherent accuracy of
Hitting Space Junk (Score:5, Funny)
> ISS Dodges Space Junk For First Time In Five Years
It must be really banged up after 5 years of hitting space junk.
Admit it! You thought it too!
Re:Can't we just span a huge net (Score:4, Funny)
in space so we could catch all the space junk? We just need to be careful that we don't catch any space stations by accident...
Considering who would be putting the net out there, what do you think the chances of accidently catching a space station (or satellite) are, hmm?
Parent
Re:Can't we just span a huge net (Score:4, Insightful)
Would have to be a pretty tight net... small particles moving fast enough can rip a dangerous hole in spacecraft.
Parent
Re:Can't we just span a huge net (Score:4, Funny)
Parent
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SUCK.. SUCK.. SUCK..!
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So move the net at that speed - 2 km/h, big deal? ;D
Re:Space help? (Score:5, Funny)
I'm not a rocket scientist. Is there another kind of drag that needs to be reduced?
The drag of being stuck in a space station! It's pretty much like being in prison, but when you stick some rockets on it, suddenly you feel like a supervillain!
Parent
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Is there another kind of drag that needs to be reduced?
Yes, they had too many transvestites on board.
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Film will be interrupted for a recap of the story at 7
Re:slownewsday? (Score:5, Informative)
Depends on the error ellipse of the orbit determination for the junk, and it sounds like the uncertainty is a good fraction of a mile in size. But in any case, the miss distance is a mile after the course adjustment, not before.
Parent
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Re:Pretty New Space Junk (Score:4, Informative)
Parent