Satellites collide in orbit

By Phil Plait | February 11, 2009 9:08 pm

[Note: The initial math I did here was wrong; off by a factor of 5 or so because I forgot to add in a piece of needed physics! I correct it in this post below, and give details in the following post.]

Wow: two satellites have collided in orbit, destroying both. This is the first time such a major collision has ever occurred.

The satellites were Cosmos 2251, a Russian communication relay satellite that’s been defunct for a decade, and an Iridium satellite, one of a fleet of communication satellites launched by Motorola in the late 90s and early 2000s.

The speeds involved are somewhat higher than your standard traffic collision. Satellites at this height above the Earth — about 800 kilometers — have an orbital speed of about 8 km/sec. However, these two satellites were on similar orbits, tilted with respect to each other by about 12 degrees. If I have accurate numbers, the physics of the situation means the collision speed was about 1.5 km/sec or so, which is pretty dang fast. Because of the way orbits work, this is about the same as the actual collision speed.

There have been collisions in space before, but never from such large satellites — the Iridium bird was about 700 kg, and the Cosmos was about the same — and never resulting in a total wipeout like this. Again, if I have my numbers about right, the explosion resulting from the energy of impact would have been about the same as detonating a ton 5 tons of TNT.

That’s a lot. It’s easily enough to totally destroy both satellites, and in fact the U.S. Space Surveillance Network has detected a substantial amount of debris, at least 600 pieces.

At the moment, that debris is expanding in a cloud, and is still too high to threaten the space station which orbits at less than half the height where the satellites collided… but eventually the debris will pass through the altitude of the ISS. It’s not clear yet how much danger the station is in. Satellites in similar orbits as the two that hit are in the most immediate danger, but again it’s unclear what will happen.

I’ll post more as I get more info.

Tip o’ the Whipple Shield to Jim Oberg, Douglas H Troy, and Davide De Martin.

CATEGORIZED UNDER: Space

Comments (118)

  1. Mount

    Forgetting the loss of Motorola’s expensive hardware, and any other potentially bad side effects, this is pretty dang cool! It’s always fun to know that stuff is happening in space, and violent explosions are at the top of my fun list.

  2. PJE

    Wow…just..wow

    Collision at 1.5 km/s..that’s something I’ll have to mention to my physics students tomorrow…

    Pete

  3. I’ve been thinking for a long time that eventually we’ll have to go up there and pick all this stuff up.
    With the utterly irresponsible Chinese satellite destroying missile test of a year or so ago and now this, well it may have to happen sooner rather than later.

  4. Wow! WOW!!
    How come the collision has not been predicted?

  5. It says a lot of us as a species that litter is continually accumulating in orbit. I’m waiting for the day when NASA sends up an orbiting trash can.

  6. Richard

    Yes, okay, but how does that affect my horoscope.

    Just kidding.

    *chirp, chirp, chirp….*

    I this thing ooon?

  7. Al Pavangkanan

    I heard Hubble is in danger. Any truth to that?

  8. Matt B.

    Looks like we might need Wall-E the space version to help us with this mess.

  9. If they were in the same orbit, and travelling at the same speed, how could this happenÉ

    More importantly, how do I get rid of this stupid É thingyÉ

  10. Davidlpf

    @Michael L, they were at the same height above the earth but traveling in slightly different paths at angle 12 degrees to one another.

  11. Kilted Canuck

    Oh no! This better not hurt any of the Earth Imaging satellites! Landsat, MODIS, Terra, RADARSAT. . . I hope you all end up ok!

  12. MadScientist

    @Mount:

    That’s a collision, not an explosion – not unless the fuel and oxidizer in the attitude adjustment motor of the Iridium bird got mixed together and ignited (presumably the Cosmos bird had no fuel left). Of course when you smash two objects together like this at high speed, junk will scatter in many directions. BA was just mentioning that the energy involved in the collision is similar to detonating a ton of TNT. Hmm … anyone care to look up the energy yield of TNT and see if BA is giving us credible numbers?

  13. Andrew Branch

    Is it even really feasible to clean the debris up? I’ve heard of scenerios of a chain reaction that could take out a lot of satellites and cause real problems for future launches. Thoughts?

  14. tacitus

    I thought they tracked the big stuff pretty closely these days. Didn’t they know it was going to happen (or at least that there was a high risk it was going to happen)?

  15. [conspiracy hat]Hmm, Iranian satellite goes up last week and this week 2 others collide.[/conspiracy hat]
    ;-)

  16. Russell

    Is this going to cause a cascade effect? In other words, are other satellites going to be destroyed by the debris from this collision, and then more from those collisions, etc?

  17. What are the odds? I mean, seriously, what are the odds?

    Well, those Iridium satellites are gonna be coming down, one way or another.

    Where’s Adam Quark when you need him?

  18. Yeah, the Bad Astronomer still hasn’t posted his thoughts on Iran’s satellite launch – why not BA? I was keen to hear your view of it.

    Personally, I send the Iranian’s my congratulations :-)

    I hope this means the Iranians get treated a bit more respect rather than the standard Islamophobic contempt and the risks of having yet another American war (or Israeli-American war really with the Jewish lobby controlling US foreign policy to the harm of everyone) in the Muslim world goes down a notch.

    I truly think the best hope for peace in the South West Asian (“Middle Eastern”) region is Iran quickly acquiring serious nuclear weapons & missiles – so that Iran and the wider Muslim world has a deterrent against being attacked by Israel. Israel being, of course, the real threat to regional peace and stability – not Iran, Syria, Gaza or any of the neighbours that Israel scapegoats for having the chutzpah to defend themselves against the jewish states religio-racist aggression.

    Yeah, off topic I know – but it needs saying. ;-)

  19. Back on topic this collision shows us we really DO need to do something about the space junk issue.

    Here in Australia, we’ve got “Clean-up Australia Day” coming up soon .. I wonder if the main space faring nations could combine to organise something similar? ;-)

  20. Grump

    The odds of that happening are astronomical. (Sorry, couldn’t resist. :-)

    Space is big. Very, very big.

    But of course, there are thousands of those things up there, and they must cross paths very often. Like rolling a D20 over and over again, sooner or later you will get three 20s in a row. These two satellites just both rolled critical failures.

  21. davidlpf

    Listening to C2C tonight and Hoagland already has a conspiracy theory about the collision claiming same hidden code that it is Iridium no 33.The collision was done on purpose and Obama and Putin were in on it.

  22. Richard Drumm The Astronomy Bum said on Feb 11th, 2009 at 9:40 pm :

    I’ve been thinking for a long time that eventually we’ll have to go up there and pick all this stuff up.With the utterly irresponsible Chinese satellite destroying missile test of a year or so ago and now this, well it may have to happen sooner rather than later.

    Not just China although I agree about the utter irresponsibility there – the United States *also* destroyed a satellite in a similarly irresponsible bit of sabre-rattling stupidity. (US 193 if memory serves.) It is unfair to single out China alone in this regard. :-(

    Perhaps any nation that destroys a satellite in such militaristic excercises should automatically be made responsible under international law for cleaning up the damage – and then also made to clean up some extra space junk as a “punitive damages example” – to discourage such idiocy?

    tacitus wrote on Feb 11th, 2009 at 10:57 pm :

    “I thought they tracked the big stuff pretty closely these days. Didn’t they know it was going to happen (or at least that there was a high risk it was going to happen)?”

    Seconded by me – they could’nt / didn’t predict this collision?
    If not then why not?
    If so why let it happen? :-(

  23. Quiet Desperation

    Any chance it wasn’t an accident? (cue scary music theme).

    Actually, I’m somewhat serious. I work in satcom, so I’ll keep my ears to the insider rumor mill.

  24. My post above is awaiting moderation now? What the ..? Why??

    Anyway :

    davidlpf wrote (Feb 11th, 2009 at 11:44 pm) :

    “Listening to C2C tonight and Hoagland already has a conspiracy theory about the collision claiming same hidden code that it is Iridium no 33. The collision was done on purpose and Obama and Putin were in on it.”

    Hah! Could be worse I guess. Imagine if it was Iridium -666! ;-)

  25. Transient29

    Yeah, off topic I know – but it needs saying.

    Not really, no. Your boner for nukes in the hands of Islamic theocracies is really naive and misguided. I could maybe scrounge up some good analysis by actual geopolitical experts, but I suspect you’d just dismiss them as a Jewish conspiracy. And I’m no lover of Israel, know that for sure.

    Islamophobia, as you label it in a textbook example of propaganda-speak, didn’t appear out of nowhere for no reason. Some of them reacted to Australia’s recent fires with a call for jihad involving the intentional setting of forest and brush fires. The Al-Ikhlas Islamic Network specifically called for a targeting of Australia.

  26. Oh & that’s my thrid post undermoderaytionnot my first – essentially

    @ Richard Drumm the astronomy bum

    It’s NOT just China although I agree about the utter irresponsibility there – remember the United States *also* destroyed a satellite in a similarly dead-brained bit of sabre-rattling stupidity. (US 193 if memory serves.)

    It is unfair to single out China alone in this regard.

    I think *ANY* nation that destroys satellites in such stupid military exercises needs to be forced under international law (“Space Law”?) to clean up the mess – and then to clean up some more space junk as a form of punitive damages on top to really discourage such idiocy.

    Lets see will this come through okay without “awaiting moderation”?

  27. Quiet_Desperation

    that it is Iridium no 33.

    Wait… the mysterious #33 is also found on bottles of Rolling Rock Pale Ale!

    COINCIDENCE?????

    I think not!

    And just for StevoR: The Jewish holiday Lag Ba’omer falls on the 33rd day of the Omer.

    COINCIDENCE?????

    Jesus was crucified in 33 A.D!

    OK, I’ll stop now.

  28. Apparently Dr. Kelso at celestrak.com hasn’t covered this satellite collision event yet, but his report on the Chinese ASAT test is a good lesson in how quickly such debris fields spread:

    http://celestrak.com/events/asat.asp

    One wonders how many more such events would effectively confine all human space activity to low orbit.

  29. Quiet_Desperation

    remember the United States *also* destroyed a satellite in a similarly dead-brained bit of sabre-rattling stupidity. (US 193 if memory serves.)

    No, it was done for the reasons stated, Steve. I work in the satcom industry, and know people in the intelligence field. It was the hydrazine tank and the beryllium content. Maybe it wasn’t a big risk, but this is a field where every resistor and capacitor is tracked and tested before being put into a spacebound package. It’s very risk-averse. US193 was a huge bird.

    Also, the intercept happened at the brink of atmospheric re-entry, so most of the debris field fell to Earth within 48 hours of the event with complete re-entry of all pieces within a couple weeks. They scheduled the intercept when they did for exactly that reason.

    Lets see will this come through okay without “awaiting moderation”?

    You sure you want to be on a skeptical site? You seem to traffic in conspiracy theories.

  30. Steve:
    Relax, if you posted an image, or video link, it goes the the moderator. It will be posted eventually.. Chill

  31. StevoR, allow me to demostratew how this works… I wil post a YouTube vid, and it will get hung up in moderation….

  32. Umm, StevoR, wait til my post gets approved! It’s under moderation, but I am not concerned, you see, any links that we post, need to be moderated and approved, so that stuff like, ohh, umm, I’m assuming cow pron does not get posted.

  33. RovetS

    StevoR: Maybe the Jews killed your post.

  34. tblaxland

    “However, these two satellites were on similar orbits, tilted with respect to each other by about 12 degrees. If I have accurate numbers, the physics of the situation means the collision speed was about 1.5 km/sec or so, which is pretty dang fast.”

    The longitude of the ascending nodes of the two satellites was such that the relative inclination between there orbital planes was closer to 90° at the time of collision. The collision altitude was 790km, orbital velocity of approx 7460m/s, so the impact velocity was closer to 10,550m/s, not 1,500m/s. The mass of the satellites was 900kg and 700kg, so the kinetic energy in the collision was a whopping 178GJ, or 42t TNT equivalent!

    Here is a good animation that shows the relative inclination of the two satellites:
    http://i39.tinypic.com/2vbk75z.gif

  35. Decks

    SteveoR,
    Decorating your sentences with a smiley does’nt help me to accept your conspiracy seeking, jew hating shallow opinions.
    I thought I might find intelligent people here exchanging thoughts and opinions about science and skepticism, and here you come along and ruin it for me.
    Thanks.

  36. fred edison

    @davidlpf

    I heard that from the official C2C “science” advisor. Dead satellites don’t do things like that, according to Hoaxland. Anywho, we’ll just send up one of our back-engineered alien flying saucers and clean it right up. And not tell anyone about it, of course. Anyone know if a Shop Vac works in space? Oh, its supposed to be a secret. Never mind.

  37. Fin Fahey

    Quiet Desperation, I’m certain you’re spot on about US 193, but on the other hand the US did destroy the on-orbit (and still operational, which annoyed a few astonomers) Solwind satellite in an ASAT test in 1985. I’m not sure about the current status of that debris cloud, but many references say there was one:

    http://en.wikipedia.org/wiki/P78-1

    The USSR also seems to have left a fair bit of shrapnel up there from exploding anti-sat sats, though I’m not sure that any of the targets disintegrated. So, irresponsible as the Chinese action was, I think, they are not the only guilty ones.

  38. Ragutis

    StevoR, I don’t hesitate to criticize and condemn Israel for it’s criminal behavior against the Palestinians over the years, but you have got to be nuts to think that a nuclear Iran is a good idea. Nuclear weapons are a terrible idea in any circumstance, but imagining them in the hands of a theocracy is blood-chilling. You want a quick solution? Get rid of that nutjob Ahmadinejad and overthrow the Supreme Leader. Iran has a huge youth population that are quite progressive and would really like to Westernize. An aggressive U.S. and Israel only helps the reactionaries and clerics remain in power.

    The collision is pretty wild stuff though. Hope it doesn’t affect the ISS, though.

    A few people talking about orbital litter. Is it going to take losing lives in orbit before governments start thinking about cleaning up after themselves??

  39. Lawrence

    With current technology, is there even an easy way to clean up a mess like that? Or better yet, the other defunct satellites & random garbage that has been accumulating since the 50’s?

  40. Phil: you have your figures wrong. The collision occurred at an intercept angle of 83.5 degrees, not 12 degrees. You are mistaking orbital inclination here with the angle between the orbital planes (which is determined by the relative difference in position of the orbital node) .

    The sats had a speed of approximately 7.5 km/s.

  41. MadScientist

    OK, I was bored:

    1. orbital velocity (at 780km altitude): ~7.5km/s
    2. relative velocity between satellites assuming they converge at 12 degrees: ~1.6km/s

    Cosmos: ~980kg, for E=1.6×10^9J
    Iridium: ~500kg, for E=0.64×10^9J

    Total energy causing damage (the actual energy of each beast is much higher): ~2.2×10^9J

    1lb TNT ~ 1.9×10^6J
    1 ton (US) TNT ~ 3.8*10^9J (1 US ton = 2000 pounds, not 1000 pounds; 1 metric ton ~ 2200 pounds)

    Hey, BA was yanking our chains! That’s only 1000 pounds of TNT.

    I think BA should show his calculations and give us links to the sources for his numbers.

  42. Lao Tzu

    It’s about time we get Wall-E up there to clean up the mess!

  43. Fergus Gallagher

    The BBC have a fantastic simulation of the collision. So realistic you’ll feel like you were there.

    http://news.bbc.co.uk/1/hi/sci/tech/7885051.stm

    (Not really – but it’s-so-crap-it’s-funny)

  44. Oh, and in the interest of details: it occurred at 16:56:00 UTC (11 Feb) at 788.58 km altitude, near long. 98.156 E, lat. 72.462 N.

  45. MadScientist

    @Lawrence:

    Clean up? Hahaha. You let the orbit decay and gravity cleans up – that’s what happened to the last SkyLab. :)

    In some cases the “de-orbiting” is deliberate – for example the Mir was instructed to fire its rockets to knock it down. There has also been talk about boosting spacecraft to escape velocity, but I don’t know of any earth-orbiting craft which had been boosted to escape; most craft like communications satellite would have expended most of their fuel for an altitude boost over its lifetime, so comms birds aren’t candidates to be boosted away; I don’t even know if their fuel load is enough to boost them to escape velocity at the time they’re deployed. Of course the interplanetary probes have all cleaned themselves up – or at least they won’t trouble the earth. Ah, Pioneers 11 and 12 – as Hadrian put it: quae nunc abibis in loca?

  46. MadScientist

    *sigh* all those calculations for nothing – so, Marco, the satellites were traveling almost at right angles at the time of collision? Wow – that would have been one big ‘bang’ – fortunately, in space no one can hear you crash.

  47. Fergus Gallagher

    MadScientist, I think you need to do the calculation in the zero-momentum frame

    v(cosmos) = 1/3 * 1.6km/s,
    v(iridium) = 2/3 * 1.6 km/s

  48. Extrinsecus

    ISS should be assumed to functions for years, so why didn’t its designer place it far above the common satelites?

  49. @ Madscientist: Yup, they were. Being both in a polar orbit, their orbit intersection is near the poles and that is where their angle of intercept is largest.

  50. A picture I shot some time ago (2007) of one of the deceased, then still happily flaring over Leiden:

    http://sattrackcam.blogspot.com/2009/02/in-memoriam-iridium-33.html

  51. so that stuff like, ohh, umm, I’m assuming cow pron does not get posted.

    I’m glad I don’t have hooves. Would make, erm, “appreciating” porn more difficult.

  52. Diego

    But wouldn’t the impact have made a new, ever more powerful hybrid satellite? It would have an over-arching need to communicate and would do so in Russian. The only way to make it stop broadcasting a constant barrage at us would be if it mistook someone for its designer at Motorola and then. . . Oh wait, this isn’t Star Trek.

    P.S. Happy Darwin Day, everyone!

  53. James

    @ Madscientist:

    From Wikipedia: An explosion is a sudden increase in volume and release of energy in an extreme manner, usually with the generation of high temperatures and the release of gases. An explosion creates a shock wave.

    … so no chemical reaction required, just a sudden conversion of linear kinetic energy into non-linear kinetic energy and waste heat.

    Did not know the difference between ton and tonne was so small though! I mistakenly thought that a ton was roughly half a tonne. God, but Imperial is such a strange system. How do people cope?

  54. AJ

    @ Diego: :D

    Generally: as others have said, I thought all this stuff was tracked these days?

    Someone took their eye off the ball…

  55. James

    Where is the best blace to get some in-depth info on this story?

    Most of the news reports I can find are for laymen.

  56. JohnW

    “the U.S. Space Surveillance Network has detected a substantial amount of debris, at least 600 pieces.”

    A 600 piece debris field? In space? Someone better get a vacuum cleaner! Nyuk nyuk nyuk…

  57. Uh-oh. Better call Maaco.
    Incidentally, all these references to the weight of the satellites provides more proof for my theory that the whole “weightlessness in space” thing is just a hoax.

  58. James – The ‘SeeSat’ list is used by a network of ‘amateur’ satellite trackers – don’t be fooled by the ‘amateur’ tag, some are subject matter experts – Marco Langbroek (see above) posts there, as do many other seasoned trackers. Click my name to go to the SeeSat list, and click Marco’s for loaaaaaads of Sat Tracking goodness.
    Bob(Big)

  59. My information says it happened on 10 Feb, though the time is the same as Marco says above.

  60. Todd W.

    What? No one’s mentioned Mega-Maid yet? A giant robotic maid with a Hoover should be able to clean up the debris in no time.

  61. John Phillips, FCD

    Tacitus, there was some speculation on the BBC news site that the Russian bird may have been out of control. Of course, so far the Russians are saying nothing, possibly because it was a dead military bird.

  62. Torbjörn Larsson, OM

    Wow, the latest entertainment, collisions in space.

    But it would IMHO be interesting to know why the Iridium failed to maneuver out of the risk zone. Did the owners skimp on orbital data and follow up? Is it an insurance market thing, rather taking a high cost of a low risk accident than preventing it in the first place?

    so that stuff like, ohh, umm, I’m assuming cow pron does not get posted.

    Perhaps. But what if we assume spherical cows?

    a sudden conversion of linear kinetic energy into non-linear kinetic energy and waste heat

    What is that “linear kinetic energy” and “non-linear kinetic energy” whereof you speak thusly? Curious mind wants to know.

    [Hmm. As kinetic energy goes as (a constant: dm/dt = 0) mass but as the square of the velocity, it seems to be both linear and non-linear, as regards physical variables. Unless you clean it up, by thinking of variables in vector terms or, please correct me here, as differentials, which in both cases should make it linear in the polynomials. Or is it a moving frame question?]

  63. Torbjörn Larsson, OM

    Ah, Pioneers 11 and 12 – as Hadrian put it: quae nunc abibis in loca?

    :-)

    And it goes on rather well, too:
    “animula vagula blandula” (my soul fleeting and gentle)
    “hospes comesques corpores” (guest of this body of mine)
    “quae nunc abibis in loca” (in what place are you to be)
    “pallidula rigida nudula” (a palid cold denuded abode)

    (Seems Hadrian was dying at the time. :-( At least the outbound but non-communicable Pioneers, 10 and 11 I believe, moves on.)

  64. Ivan

    1.5 Km/s = 5400 Km/Hr = 3375 Miles/hr. Just to have a better idea of the speed.
    Can’t wait until some quack decides that it is a signal of the end, the beginning, the rapture, the ilumination, the obscurantism, the spiritual, the inmaterial, alien anger, russian evil, USA evil, big spagetti monster evil, and everything but a crash between two big, fat objects.

  65. Cheyenne

    Here’s an interesting quote that I found on HuffPo

    “It’s gotten so bad that orbital debris is now the biggest threat to a space shuttle in flight, surpassing the dangers of liftoff and return to Earth.”

    I didn’t know it was that big of a problem. It seems like this is might become an exponentially bigger issue as time goes on.

  66. Old Muley

    Hmm, I thought my Directv was acting up a bit yesterday…

  67. As far as the ‘someone should be keeping an eye on this’ argument, the practice is still more of an art than a science. I work with active spacecraft, and we have a service which reports potential collisions to us. Unfortunately, the position uncertainty for our space craft is on the order of tens of meters (that is, larger than the spacecraft itself) and the uncertainty for inactive space junk is much higher. So the whole system devolves into probability, and I haven’t heard of any new systems coming on line to improve it yet.

    I’m pretty sure I saw an Iridium release saying that Iridium 33 was still active. If that’s the case, they should have had some active monitoring, yet that monitoring is required yet.

  68. Sorry…typo

    “yet that monitoring is required yet”

    should have read

    “yet that monitoring is not required yet”

  69. Probably more information coming on this website:

    http://orbitaldebris.jsc.nasa.gov/

  70. Simon Richard Clarkstone

    Why did neither satellite maneuver to avoid the collision? Neither of their orbits appears to be secret. Isn’t it standard to send defunct satellites into the atmosphere, since they lack the ability to change orbits in circumstances like that?

  71. Rift

    Steve R: “Yeah, off topic I know – but it needs saying.”.

    Perhaps, but not here. Why does it seem so hard for some to stay on topic on Phil’s blog?

    ON TOPIC- The Roleplaying Game (pen and paper) by Steve Jackson Games “Transhuman Space” had an organization called the “Vacuum Cleaners” that spent all their time cleaning up 150 years of junk in low earth orbit. (It was sat in 2100 AD.)

  72. Carlos

    I just ran a Satellite Toolkit simulation using the latest pre-collision orbital elements.

    Phil – the two orbits were tilted about 100 degrees to each other, not 12! The resulting collision velocity is around 11.5 km/s

  73. Russ

    I read a lot of people mentioning “cleaning up space”. And my initial thoughts are that the amount of energy required to move to all the different orbits to collect junk would just be too huge.

    Then I considered another idea. I high orbit satellite with a large solar array and a laser. The laser would be aimed at small pieces of space junk for extended periods of time. The best time to zap stuff with the laser would be when the object is coming around the side of the earth so that the velocity of the object is slightly reduced. Sure not by much, but eventually the orbit would drop enough for the chunk to start hitting atmosphere.

    Add more satellites and you can get rid of junk quicker.

  74. Quiet Desperation

    The Roleplaying Game (pen and paper) by Steve Jackson Games “Transhuman Space” had an organization called the “Vacuum Cleaners” that spent all their time cleaning up 150 years of junk in low earth orbit. (It was sat in 2100 AD.)

    The anime series Planetes was about a space debris team.

    Let’s try this. I find if you clip the http from the URL, it passes moderation and still shows up as a link.

    en.wikipedia.org/wiki/Planetes

  75. Quiet Desperation

    Or not. Geez, it did the last couple times. :-

  76. @ Tom:

    Yup, I made a typo: should be 10 February indeed

  77. Russ

    StevoR-Correcting, OMG, its the Jooooooooooooooooooooooooos.

  78. Tomas

    Here’s is the diagram of the collision. If that’s correct, it looks that the sat’s trajectories cross at almost 90 degrees …

  79. fernando

    Exactly, about 1000 pounds of TNT (1050 to be exact)… yes, wall-e up there as well… er… those guys at the IES are going to ask for a dangerousness bonus… don’t even think about it!

  80. @ Tom again:

    correct position (this time gleaned from both satellites) with the date correct is 97.89 E, 72.50 N

  81. T.E.L.

    Simon Richard Clarkstone Said:

    “Neither of their orbits appears to be secret.”

    This is a good opportunity to point out that no satellite’s orbit is secret, even those of secret satellites. If it can be seen from the ground, then its orbital parameters can be measured. Satellite tracking is even an amateur hobby.

  82. Bill Nettles

    Hey, Congress! NASA needs about a trillion dollars to clean up space or our economy is going to tank because all the satellites will be destroyed by this debris. And we need it yesterday!

  83. maurice clark

    @ Quiet_Desperation:

    The USA DID destroy a fully-functional satellite as a military test some years back. Do a search for Solwind.

  84. Hungarian

    It’s fast, but not cosmic. The SR-71’s top speed was around 3600 km/h, that’s about 1 km/s.

  85. DB

    So could this be the start of a Kessler Syndrome

    en.wikipedia.org/wiki/Kessler_Syndrome

  86. Gary Ansorge

    Russ:
    Laser vaporization of debris to slow its orbital velocity and drop it into the atmosphere is one solution. Another (proposed by Mike Combs, physicist) is basically a 100 meter diameter styrofoam ball(with nitrogen for the gas spaces) in an opposite orbit to the debris field, captures small debris intact, slows large debris to cause de-orbiting and because of it’s large surface area to mass would itself de-orbit very quickly. Would make for some very pretty re-entry fire works,,,

    Remember, there is a small amount of atmosphere even out to 1000 Km. Left to themselves these sats orbits would eventually decay and impact the denser atmo, burning them up. Which is why we have to keep boosting the ISS, just to maintain its orbit.

    GAry 7

  87. Collision my ass! I know a Stargate Command cover-up when I see one. It probably happened in the battle between Atlantis and the Wraith. They can’t fool me!

    ;)

    Wish we had video. It’s a shame it happened, but at least then we’d get a cool wreck out of it.

  88. Rift

    Thanks Quiet Desperation, that looks really cool, gonna have to check that out. Too many manga and anime, too little time…

  89. Chip

    I think a piece of debris was recovered from the collision. The event seems to have altered its programming: http://www.ex-astris-scientia.org/scans/factfiles/nomad.jpg

  90. T. Noel

    All math aside, I do certainly hope that most of your readers are familiar with a concept called Kessler Syndrome. This is a good example of a really bad catalyst of such an event.

    If we really want to travel in space, we really need to work harder at preventing this sort of thing.

  91. You’ve got it all wrong when it comes to removing Space Junk. Some good ideas, but, I think we should send a door to door Kirby Vacuum salesman to the ISS and see if the crew wants to buy one. That way they can attach the Vacuum to the front of the station, and vacuum all the debris up.

  92. DB

    @Miichael L.

    Make sure they get one with the Black Hole attachment.
    Gravity is the only thing that sucks in a vacuum.

  93. Quiet Desperation

    OMG, its the Jooooooooooooooooooooooooos.

    The Juice? Isn’t he in jail in Vegas now? ;-)

  94. 100 meter styrofoam ball with pieces of satellite debris sticking out of it…. Guinness world record for largest craft project ever?

  95. Todd W.

    @Sciencegoddess

    That or most painful styrofoam ball fight ever. “Ow! Why’d you have to throw a satellite-debris ball at me, man!”

  96. @DB… It’s a Kirby! It can do anything!

  97. Quiet Desperation

    The USA DID destroy a fully-functional satellite as a military test some years back.

    I know a guy who was involved with that bird. Solwind was a solar observation satellite that was failing. Most of the instruments were dead. The software workarounds (it needed to be reconfigured repeatedly) to continue testing with the remaining instruments were causing problems on the sat control network, so they flagged it as a convenient ASAT test in 1985. All debris was down by the early 1990s. In fact, the results of that test were used as lessons learned in the US193 shoot down.

    heasarc.nasa.gov/docs/heasarc/missions/p78-1.html

    The main complaint against the Chinese ASAT test was the altitude. It was way out of the atmosphere, so you get debris lasting indefinitely. It was also a kinetic energy weapon instead of a warhead, so there was nothing *but* debris. Over 2000 chunks of trackable size, and it single handedly increased the number of tracked object by over 20%.

  98. MadScientist

    @ncc1701:

    Haha – weight indeed. OK, so it’s the mass of each satellite which is quoted. As for the weight, they’d weigh slightly less than they would on earth with their given orbit. After all, gravitational acceleration is proportional to 1/r^2 and at the surface that’s already 6300km, so at the altitude of the orbit r~7080km. Unless I got sloppy with punching buttons, that means the weight is about 79% of what it is at earth’s surface.

    For the less physics inclined, at the ISS orbit and the range of shuttle orbits, the occupants are *not* weightless – for example, trips to the ISS give you about 87% of your weight and the highest shuttle missions were roughly at the altitude of these colliding satellites. The reason we see astronauts, cosmonauts, and others ‘floating’ in the cabins is that the spacecraft are falling as fast as its occupants – this is just what happens on the ‘vomit comet’ except that the spacecraft are perpetually falling whereas the vomit comet needs to pull out of the dive before it hits the ground.

    Now onto the BA’s latest post and apology for his goof-ups …

  99. J lee

    this was on the korean(S) newspaper, and it said that currently there are about 1200 satellites in orbit. Is this true?

  100. James

    @Torbjörn Larsson:

    I was playing fast and loose with the terms the way I would with a layman, refering to the fact that in state 1 we had a chunk of metal going in a straight line and in state 2 we had a million chunks of metal going every which way liberaly mixed with rapidly cooling metal gas/plasma.

    I wasn’t trying to say anything profound physics-wise, just that Madscientist had his definition of explosion wrong :)

  101. StevoR

    Excessive jewish-Israeli influence on US foreign policy isn’t “conspiracy theory” but fact.

    Nor am I not anti-jewish, just Pro-Palestinean! ;-)

    Actually pro-Humanity when you think about it. Israel violates international law, basic human rights principles, committs endless war crimes and creates anti-semitism daily. (& not just anti-Palestinean and anti-Arab variety anti-semitism but anti-semitism directed, rather justifiably, against the perpetrators of so many war-crimes and crimes against humanity – Israel & the wider Israeli-Jewish lobby.)

    Ultimately, Israel will harm everybody incl. the Jews themselves. There is no better way to wipe out the jewish people, should you actually want to – which I don’t – than get them all together in one small piece of land then really, & I mean really get the neighbours of that land to hate you.

    Israel will not remain militarily superior forever. One day it will lose its ability to terrorise its neighbours into submission – and will have the choice – learn to respect & get on well with its neighbours – or perish.

    It is hardly naive to think Mutally Assured Destruction works the USSR-USA Cold War & the current India-Pakistan situation is proof of that.

    Mahmoud Ahmadinejhad is certainly no crazier than “Dubya” Bush and Iran too has a right to exist without fear of attack.

    Why might I ask should Israel and USA, nations demonstrably more aggressive and with far worse records of respecting the rights of others have WMDs and yet not Iran? There is no answer for that question which is not blatant hypocrisy.

    @ Ragutis : (Feb 12th, 2009 at 2:58 am)
    StevoR, I don’t hesitate to criticize and condemn Israel for it’s criminal behavior against the Palestinians over the years, but you have got to be nuts to think that a nuclear Iran is a good idea. Nuclear weapons are a terrible idea in any circumstance, but imagining them in the hands of a theocracy is blood-chilling.

    Too late. Israel is a religio-racist apartheid military theocracy – & it already has secret nukes in violation of UN law. The US was ruled until recently by a man (in the loosest sense of the word) who believes God told him to invade Iraq. I’d prefer Iran had nukes than either of those nations -its record on the international stage is much more responsible and peaceful!;-)

    (It is historical fact that Iran hasn’t actually attacked any other
    nation since WWII – but rather been attackied by a few notably Iraq with
    Amercian encouragement.)

    Ragutis continued :
    … Yu want a quick solution? Get rid of that nutjob Ahmadinejad and overthrow the Supreme Leader. Iran has a huge youth population that are quite progressive and would really like to Westernize.”

    Sounds like the neo-cons plan for Iraq. Weren’t we going to be greeted
    with flowers and cheering crowds there? :-(

    No. Reigeme change just does NOT work. Accept it. Just because the US doesn’t like some other govt does NOT give it the right to attack that nation. Its time this axiom was acknowledged and the US stopped itshysteria and started behaving more responsibly and multilaterally – hopefully Obama will the USA in that direction.

    “An aggressive U.S. and Israel only helps the reactionaries and clerics remain in power.”

    Now on that we agree! :-)

    As for emoticons, well I like ‘em! ;-)

    Oh & the reason I was worried about my post coming though wasn’t paranoia – I’ve just had a few problems posting things on other threads here before.
    :-(

  102. cardoc

    I have to chime in on the 5 tons of TNT calculation. Solving for the energy of an inelastic collision requires that you know the resultant vector (displacement AND rotational) and mass (and polar moment) of every particle that leaves the point of the collision. MOST of the kinetic energy of both birds was conserved because every fragment of them was still moving at near orbital velocity when following the event.

    I imagine that the actual lines of motion were less than perfectly aligned. The resulting “glancing blow” would cause both birds to leave the scene spinning very very rapidly which would cause them to rip apart into thousands of fragments.

    Taking the total kinetic energy of both objects only works if they end up in a single mass and and then you still have to subtract the KE of the resultant blob.

    There is no way to ever know how much energy was released. One thing is for sure. At those speeds on a crossing vector there was plenty of energy to destroy both birds.

  103. Robert

    I’d like to see our resident mathemeticians share a little bit more detail about their calculations and assumptions.

    For instance, exactly how did you determine the percentage of kinetic energy that resuults in spacecraft damage? What is your conversion rate of Joules to tons of TNT?

    (Please do all work in metric…along those lines, is tons of TNT a metric ton or a British ton?)

    Thanks. This just gets everyone on the same page and provides a nice physics primer for verybody.

  104. John

    Is it feasible to sweep smaller junk into some sort of capture net?

    http://techfox.comicgenesis.com/d/20041112.html

  105. kathrine

    As a reply to WikiSky on Feburary 11th, 2009
    i DID predict it. well it wasnt a prediction so to speak, but a premonition the day before.
    I knew this was going to happen for certain and parts of debris were going to land over texas. But who am i going to tell? No one will listen to a teenager. I know this sounds obsurd, but its true! Trust me.. i wouldnt be wasting my time posting this if it wasnt.

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