ISS Dodges Space Junk For First Time In Five Years

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."

In SOVIET RUSSIA..

You watch out for spy satellites!

Re:In SOVIET RUSSIA..

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.

A mile?

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?

Re:

I would guess for the same reason the people at the use probability for theirs. Interestingly, there's one object on there that meets the "more probable than 1 in 10,000" threshold for Earth (two decades after Apophis and with half the explosive energy, though). [nasa.gov]

Re:A mile?

Because when dealing with the vastness of space a mile is pretty damn close.

Re:A mile?

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.

Re:A mile?

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.

Re:A mile?

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.

Re:A mile?

An HTML entity shouldn't be required. It's 2008; we should be able to stick Unicode into these boxes.

Recycle It!

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.

Within 1 mile?

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?

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.

ISS altitude graph

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.)

Hitting Space Junk

> 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:Russia just can't tell the truth.

Russian news avoids [en.rian.ru] mentioning the Russian satellite and just refers to the ISS dodging a "cluster of garbage."

Re: "garbage"

maybe they were just quoting the engineers who had built the satellite...

Re:Russia just can't tell the truth.

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.

Re:Russia just can't tell the truth.

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.

Re:Can't we just span a huge net

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?

Re:Can't we just span a huge net

Would have to be a pretty tight net... small particles moving fast enough can rip a dangerous hole in spacecraft.

Re:Can't we just span a huge net

what about Mega Maid? she could vacuum up all of the space junk

Re:Space help?

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!

Re:slownewsday?

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.

Re: it needs friggen lasers

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

Re:Pretty New Space Junk

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.