Following last week’s close call with a piece of space debris coming near the International Space Station, NASA is keeping an eye on another piece of debris which could come even closer to the station. Current estimates say the debris will approach the ISS early Tuesday morning, at about 3:14 a.m. EDT (0714 GMT) at a distance of only 2,600 feet (793 meters).
“The piece of debris which is expected to come close to ISS early tomorrow is from an explosion of a Russian navigation satellite in 1981,” NASA’s Chief Scientist for Orbital Debris Nicholas L. Johnson told Universe Today. NASA will decide by later today (Monday) if they will use the thrusters on the Zvezda module to move the ISS away from the debris. If so, the thrusters would fire for a short maneuver at 9:54 p.m. EDT tonight (01:54 March 17 GMT). Since space shuttle Discovery is on its way to rendezvous with the station on Tuesday, changes would have to made to the shuttle’s rocket firing sequence to compensate.
Johnson said that small pieces of debris have already collided with ISS on many occasions, but these debris to date have not affected the safety of the crew or the operation of the mission. “The dedicated debris shields on ISS can withstand particles as large as 1 cm in diameter,” he said.
Update: (5:35 CDT) NASA is now reporting that a maneuver will not be necessary for the ISS to avoid the orbital debris.
The ISS is said to be the most heavily shielded spacecraft ever built.
Johnson added that on average, close approaches to ISS occur about three times a month. An approach of debris is considered “close” only when it enters an imaginary “pizza box” shaped region around the station, measuring 0.75 kilometers above and below the station and 25 kilometers on each side( 2,460 feet above and below and 15.6 by 15.6 miles). NASA the size of the debris is not precisely known as yet, and how close it will come to the station. “This piece of debris and that which passed close to ISS last week are not associated with any recent events, such as last month’s satellite collision,” Johnson said.
Last week a rather large 12.7 cm (5-inch) piece of debris from a spent rocket motor came within 4.5 kilometers (2.8 miles) of the station. Usually, when debris is seen as on a possible collision course with the ISS, the station is able to fire thrusters and maneuver out of danger. However, because of the late notice, there wasn’t time to perform the thruster maneuvers, and the crew closed all the hatches on the station and retreated to the Soyuz capsule until the threat had passed.
According to MSNBC, the space station’s crew has taken refuge in the Soyuz as many as five times before today due to concerns about passing space debris, and the ISS has had to perform 8 collision avoidance maneuvers in the past 10 years.
Wired reported that information from a NASA database details 1,951 debris impacts to the space shuttle through 2006, requiring windows and radiators to be replaced.
“It’s yet another warning shot that we really have to do something about space debris now. We have to do something on an international level,” Harvard astrophysicist Jonathan McDowell told the Associated Press.
“As we continue to put stuff up there, the predictions are that the rate (of close calls) will increase,” added William Ailor, director of the Center for Orbital and Reentry Debris Studies at the Aerospace Corp. in El Segundo, Calif.
The U.S. Space Command tracks 13,943 orbiting objects 4 inches or larger. Only about 900 of those are working satellites, McDowell said. The rest is litter. There are thousands more smaller pieces of junk that can’t be tracked as easily.
We’ll keep you posted on the lastest space debris issue.
Sources: Email exchange with Nicholas Johnson, MSNBC, AP, Wired
Somehow someone needs to find a practical way to clear the space around the earth of dangerous debris. Also no satellite should be launched without a way to either bring it back down or send it far beyond the geosynchronous orbit.
I’ve always wondered, when they say they may have to do a burn to move out of the way, then do they also have to do and equal but opposite burn to stop moving? else just keep moving right?
Procyan Says: March 16th, 2009 at 4:33 pm
“I’ve always wondered, when they say they may have to do a burn to move out of the way, then do they also have to do and equal but opposite burn to stop moving? Else just keep moving right?”
If the Space Station – or another spacecraft – has to do a “burn” to avoid a piece of debris – it is no different than the orbit raising manoeuvres that are reported regularly anyway. Most months the ISS is involved in an orbit changing manoeuvre simply to maintain height in orbit, and resist atmospheric drag. With so many visiting spacecraft it is usual to use the Shuttle, Soyuz, Progress and latterly the ATV vehicles to give the station a boost every now and them. Although the ISS might have to “side step” the odd piece of space junk (when it gets sufficient advance notice) from time to time [8 times in 10 years], there would be little reason to “step” left after “stepping” right – as that would use up twice the amount of propellant as the original manoeuvre – for no good reason!
Isn’t there still a spanner floating about up there at 40,000 miles per hour? Looks like it time to build Sir Arthur C. Clark’s ‘Space Hoover’
Could you do an initial run with strongly magnetic satellites that are then brought down to burn up? that could remove a lot of the debris.
Sooner or later, there will be a catastrophic
hit by a piece of debris too small to track and hit a manned vehicle and will cause unfortunate casualties.!!!! Time is now to clean up Earth outer space by whatever tech is available.
A destructive collision with space junk or a golf-ball sized meteor is inevitable for the ISS. Hopefully a means to detect and deflect cosmic speed object will be developed. Past unknown probe failures may have been lost due to ‘running into something’ or ‘something running into it.’
Just thinking out loud, the increase in space junk could down the track be a good thing. It would force satellite and shuttle and station designers to improve shielding technology (physical or otherwise) to resist larger impacts, which in turn will certainly help the survivability of both manned and unmanned interplanetary missions in the future.
Maybe I watch too much Star Trek, but I’m sure decades or centuries from now if they do have Star Trek sized spacecraft, they would certainly need to be built to withstand a lot more than an impact from space junk or meteorites just few inches in size!
Look on the bright side, maybe one day we’ll have so much space debris around the Earth that we’ll have created rings around the planet!
Simon Douglass-a 25mm bolt orbiting at 18k mph or 30k KPH colliding at right angle to a satellite or manned vehicle will be like going through household aluminum foil!!. The same tech used to protect armored vehicles like an outer layer than spacing and the main layer will be needed, perhaps 4-5 layers with spacings!!! Of course, cost and weight are the reasons why this will not happen until
a disaster strikes!!! I dread the day when the
news about a disaster strikes!!!!
Sci-Fi Si Says: March 16th, 2009 at 5:22 pm
“Isn’t there still a spanner floating about up there at 40,000 miles per hour? Looks like it time to build Sir Arthur C. Clark’s ‘Space Hoover'”
Reference Sci-Fi Si and the 40,000 mph spanner. Anything “floating” around at 40,000 mph isn’t going to be hanging around very long. An object in orbit around Earth for any length of time moves at about 25,000 mph / 40,000 km/hr. Apollo CM capsule re-entries on return from the Moon, shortly before atmospheric interface were moving at about this speed – as will anything arriving from heliocentric orbits; or faster (up to 35,300 mph / 56,500 km/hr) ± 64,800 mph / 103,700 km/hr taking Earth’s speed in orbit about the Sun.
Error correction to my previous post. Orbit velocity should read 18,000 mph / 28,000 km/hr – but you should get the picture. the spanner is going much to fast to be in orbit.
We want to see more attention devoted to perchlorate. Give us perchlorate, and give it right now.
star-grazer – RE your bolt being “like going through household aluminum foil” – my point exactly! Using CURRENT technology, this is the case, and using CURRENT technology, you are correct – the only way to avoid this would probably be with armour plating, which is way too expensive to send into space, hence why I said space junk might force “designers to improve shielding technology”. By this I meant design some totally new method of shielding, rather than improving existing methods.
These new shielding technologies WILL happen one day as new materials are created, it’s just a matter of when, and whether the space agencies involved have the sense and foresight to implement them before a disaster DOES strike.
There are so incredibly many ways to deal with the debris problem.
One was recently applied by Iridium when one of their sats was knocked out, see the February 14th article “Orbital Spares: Iridium Already Replaced Destroyed Satellite”. The underlying countermeasure is called “redundancy”. Another countermeasure for example is the “evasion maneuver”, as mentioned in this article.
The most famous incident till now was “Houston, we’ve had a problem here”. We already been confronted with this. So this is really nothing new. Despite Apollo 13 there were so many subsequent manned space missions.
dollhopf -I understand what you mean, but hiiting a manned vehicle causing casualties
will immediately halt manned flights. The lossed loved ones will not be redundancy.
The days of Apollo13, space debris was not really much of an issue, however, after nearly 40 years since Apollo 13, far more debris is a deadly concern and new nations are joining in scattering their junk. I do wish for the relatively safe space of 1969-72 but those days are over.
Redundancy doesn’t deal with the problem of junk. In fact, it adds to it. Especially if you send up a few redundant satellites which end up having a problem and become uncontrollable.
Evasive movements can also add to the problem. You move from one location to the other; when in fact moving there could put it in more danger weeks later. Eventually you run out of fuel.
Creating satellites which can maneuver to avoid collisions increases costs, it also adds to the size and amount of parts a satellite requires. As in more parts which end up in orbit due to some unforseen reason.
Larger satellites in LEO make it harder to predict exactly where they will be several days later, since they will be affected more than small objects by drag when the atmosphere expands.
Not to mention, in order to ‘evade’ you need to be aware of the problem. Not always something which can be seen or even easily predicted.
The dynamics of changing an objects location in orbit, is quite a bit different than the dynamics required to do so in Earth’s atmosphere.
to. star-grazer, Mr.Obvious
I do approve with your cons, nevertheless: redundancy and evasion are also approved concepts. A third concept is “tracking” (also already in use). A fourth is “avoiding” in general: to decrease any form of human made debris in earth orbit.
My underlying argument is simply that there is no single true path to salvation. The solution has naturally to consist of a multitude of maybe independent efforts and countermeasures and that every single little improvement is of value!
Being mortal and fragile, humans always will be afraid of adverseness, which is one of our fundamental conditions. And space missions will always be risky.
My second argument: it would be the most contemptible “contermeasure” to refrain from manned space flight due to casualities, because it would be rediculous in comparisson with the fact that the same authorities would never ban their own ability to conduct war. And war causes more casualities. Too many men and women were maimed or killed in intentionally contucted wars since Grissom, White, Chaffee, Komarow, Dobrowolskij, Patsajew and Wolkow had died.
Anytime anywhere somebody is confronted with his or her violability. To stay in bed in the morning is no reasonable strategy of avoidance all the time 😉 Instead the risks need to be reduced continuously.