Cosmic Collision Over Siberia

Space is mostly empty, but sometimes it isn't empty enough.

Two days ago a pair of orbiting satellites collided 480 miles (780 km) up over Siberia. One was Cosmos 2251, a defunct communications satellite launched in 1993 by the Russian Ministry of Defense. The other was named Iridium 33, one of several dozen spacecraft in a globe-girding commercial communications network.

It's not yet clear exactly how many satellite shards the smashup created; more than 600 have already been logged by the U.S. military's worldwide satellite-tracking network. A more accurate debris census — and, more importantly, how they're distributed in orbit — will take a week or so to sort out.

Satellite snapshot
A snapshot of the thousands of satellite circling Earth in low-altitude orbits.
NASA / Johnson Space Center
This unplanned meeting in orbit is unprecedented, but it was bound to happen sooner or later. Ground-based cameras and radar currently keep tabs on more than 13,000 orbiting objects, everything from fragments the size of tennis balls to the International Space Station.

Speaking of ISS, it doesn't appear to be in imminent danger. It orbits quite a bit lower, typically 220 miles (350 km). There's a little more worry concerning the Hubble Space Telescope, currently circling at a height of 350 miles (565 km). Both of the colliding spacecraft had high-inclination orbits (Cosmos 2251 at 74°, Iridium 33 at 86°), and depending on their post-crash speeds, some of the 1½ tons of fragments might end up either much higher or much lower.

The February 10th collision was an accident: the Russian craft was inoperable, and the Iridium, though apparently equipped with a maneuvering rocket, hadn't known it was going to be hit. As worrisome as all this might seem, it totally pales compared to an intentional space smashup that occurred two years ago.

Let's not forget that on January 11, 2007, the People's Republic of China launched a ballistic weapon that struck and destroyed Fengyun 1. The resulting fragments created more space shards than any other event in the history of satellite exploration, creating a hazardous cloud that has spread to altitudes ranging from 300 to 2,500 miles.

According to a recent newsletter from NASA's Orbital Debris Office, pieces of Fengyun 1 and its annihilator now total nearly 2,400, accounting for more than 25% of all the objects being tracked at low orbital altitudes. And the estimated count of smaller bits, 1 to 5 cm across, exceeds 150,000. Some of these will remain aloft for decades, others for more than a century.

Accidents will happen, but to knowingly put so many other spacecraft at risk is unconscionable. Remarkably, five years earlier China's National Space Administration (CNSA) had signed a United Nations agreement to help reduce the amount of space debris.

18 thoughts on “Cosmic Collision Over Siberia

  1. Eric F. Diaz

    I do worry about our precious Hubble Space Telescope. I didn’t know about the incident involving China launching a ballistic weapon that struck and destroyed Fengyun 1. And I agree, that to knowingly put so many other spacecraft at risk is unconscionable!

    Tell me, do you happen to know if any our GPS satellites are at risk?

    Thank you, for the very enlightening blog entry.

  2. Bob Bailey

    I am an American who has lived in Taiwan for 13 years. So, I’ve had the opportunity to observe China pretty close up while enjoying the freedom (including that of the press) offered by the Taiwan government.

    Sadly, despite having become a major power on the world stage, China still often does not live up to the promises and agreements made by the PRC government, be it human rights, trade, health, etc.

    (Oh dear, now I hope they do not ban me from traveling to Shanghai this summer to view the eclipse. I went to Hami last summer.)

  3. Lin4dGary Linford

    It is more than an act of malicious mischief to generate large amounts of space debris in orbit around the Earth or other planets. Sufficient quantities of counter-orbiting space debris can put the lid on space travel to or from the affected planet. Bands of debris injected at varying heights and orbiting in opposite directions create the dreaded “Pandora’s Box” effect making it difficult if not impossible to survive a launch. Terrestrial inhabitants are then trapped on the Earth’s surface!

  4. carsten

    Most likely the best way to shoot down a satellite with a missile would be to hit it on the downward part of the ballistic trajectory rather on the upward leg. This way a lot of pieces would be put on a reentry path. Also, more junk could be knocked out of the sky if the impacting missle also came from front and the resultant forces acted as a retro rocket to cause deorbiting. Any small bits pushed into a lower orbit where the air is thicker would more quickly decay into reonty mode due to increased air resistance. Anyway,it could be a hell of a show down range!

  5. A. Szautner

    The collision velocity was around 40,000 km/hour. The two satellites were traveling in near circular orbits at a similar altitude: Iridium 33 was at 776 x 791 km, while Cosmos 2251 was at 767 x 803 km. They therefore had similar orbital velocities (with respect to the earth) at the time of impact (each moving along at roughly 7.5 km per second). But their orbital planes were inclined to each other by about 100 degrees, meaning that they hit each other on the fast side of the 90-degree inclination difference.

    In the event of a fairly direct strike, the population of debris above 1 centimeter across generated could easily exceed a million. Considering the geometry noted above, at least a quarter of the fragments would have entered orbits with considerrably lower perigees. Those are fragements that may be expected to deorbit and reenter the atmosphere in a fairly short time-frame (most under several decades). But the rest was boosted into either higher orbits (higher apogees) which won’t deorbit for MILLENNIA, or laterally into orbits deviating from the two original satellites but remain at much the same altitude (for centuries). End Part 1 of 2.

  6. A. Szautner

    There are two conjunction points where these clouds of fragments will repeatedly meet intersect: at the original impact point (with respect to the stars) and the antipode of that spot, somewhere over the Antarctic. Some collisions between fragments in these two locations will undoubtedly ensue, but the real problem is that these locations are also so near the most densely-populated spots where literally thousands of satellites and boosters ply near-polar orbits.

    Absolutely not, no, this is NOT a scenario we can easily live with, by any stretch of the hopeful imagination. What happens when another 1 or 2 big collisions transpire? These satellites INFEST that altitude, and the regions above the poles are CRAMMED with them. We may easily knock off our ability to become a truly spacefaring civilization – just because we sent so much junk into polar orbit to satisfy cell-phone users (the current Iridium system serves only about 300,000 paying customers) and military ‘intelligence’ anaylists, which is utterly superfluous when heads of state don’t understand what the satellite analysts tell them and go ahead and do whatever they have in mind to do anyway. It’s truly a dispicable situation to watch as we encase ourselves within an impassable barrier. It’s high time that governments institute international regulations to stem the launch of space hardware into the neow most sensitive orbital regimes. Part 2 of 2.

  7. A. Szautner

    Carsten: oh, yes, of course, one hell of a good show downrange.

    “Jolly, good. Jolly, jolly good show”. (You have to watch ‘THe Bridge on the River Kwai” to get the reference to THAT.

    Yes, an interesting ‘problem’: ‘A Method of Producing Lots of Artificial Meteors by Intentional Satellite Demolition.”


  8. Fred ShumanFred from Laurel, Md

    Two points come to mind. First, in light of what several posters have said here, the deliberate creation of thousands of pieces of orbiting debris, especially after the nation doing this has signed an international agreement to limit such debris, is not just unconscionable (any nation committing such an act will hardly be impressed by that label!); no, it is quite possibly an act of war; certainly of hostility. And any nation, especially a spacefaring nation, that doesn’t immediately and sternly inform them of this, and start considering punitive action, is complicit in that act. This debris is nothing more or less than ‘space shrapnel,’ aimed at a whole plethora of legitimate satellites. If the UN weren’t a useless collection of malignant dictatorships, IT would be the body that could take care of this. Maybe we need to form a US(pacefaring)N, but that might not be any improvement, either.

    Second, A. Szautner’s observation that the impact point and its antipode are condensation points for this debris cloud, raises the possibility that in the future there may be a way of capturing or redirecting most of the particles in such a cloud into re-entry and rapid-decay orbits by doing something at one of those two spots, thus effectively ‘sweeping’ that cloud. I imagine that over time, these condensation points would diffuse, though, so time would be of the essence. Any ideas what could be done at such a condensation point to clear debris without creating more?

    If I could add a third, probably unrelated, point, today happens to be Galileo’s 445th birthday.

  9. jmmahony

    “The February 10th collision was an accident: the Russian craft was inoperable, and the Iridium, though apparently equipped with a maneuvering rocket, hadn’t known it was going to be hit.”

    I’ve been wondering about that (the last part). We track many thousands of bits of space junk, and I’ve occasionally heard about the ISS making small adjustments in its orbit to avoid a possible collision with one of these bits. So wouldn’t a company with nearly 100 satellites in orbit (currently 89, I think) put just a little bit of effort into using this same data to keep their satellites safe? The Iridium sats are highly maneuverable. The Russian sat was large enough that it would have been detected very regularly by the US space junk monitoring agencies, so its orbit would have been known to high accuracy. While trying to calculate all possible collisions between any pair of those many thousands of bits might be computationally intensive, if you’re only worried about 89 of them, it shouldn’t be too hard. 89 X 13,000 gives about one million possible pairs to check. Not trivial, but I wouldn’t expect it to be too hard for a high-tech company.

  10. Peter WilsonP Wilson

    “Don’t get too worked up about the pair of spacecraft that collided in orbit on February” How dare S&T not hype this! “Remarkably, five years earlier China’s National Space Administration (CNSA) had signed a United Nations agreement to help reduce the amount of space debris.” And Japan agreed not to hunt whales…

  11. Peter WilsonP Wilson

    “Don’t get too worked up about the pair of spacecraft that collided in orbit on February” How dare S&T not hype this! “Remarkably, five years earlier China’s National Space Administration (CNSA) had signed a United Nations agreement to help reduce the amount of space debris.” And Japan agreed not to hunt whales…

  12. Enrico the Great

    I see that this website has been up long enough that the political guys have now come out of the wood work. OK, my two cents: I have never been a pacifist, I am rather right-wing in my politics, indeed my friends see me as rather a hawk when it comes to foreign relations, HOWEVER, calling China’s destruction of its own satellite an ACT OF WAR is a stretch. While I agree that what China did was HIGHLY IRRESPONSIBLE and an unfriendly act directed at every other nation on the Earth, it is not something that I would advocate war as a solution to. There are other ways of ensuring that China ceases this type of activity that should be used before war us considered as an option. May I point out that war between spacefaring nations would add to the problems of space debris because each side would have to destroy the other side’s communication, recconaisance, navigation and even weather satellites?

  13. Ted Welti

    Saw about 100 star-like objects gliding through the sky over Leesburg, VA on June 1, 2014 10:00pm to 10:15pm south to north each one looking like a satellite looks if you’ve ever watched one of those glide across a starry sky. Does anyone think it could have been debris from the Irridium satellite collision a couple of years ago?

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