In the Cosmos/Iridium Collision, Which Satellite Won?

©Stratfor Global Intellegence

When two satellites collide at 790 km above the Earth’s surface, who really cares which satellite “won”? It’s going to be a mess; chunks of metal and shards of solar panels exploding to life after their once-solid satellite structures impacted at a velocity of 11 km/s (that’s kilometres per second). Both satellites are losers, twisted, shattered remains of their former selves, cluttering Earth-orbit, causing all kinds of stress for other vehicles flying around in orbit.

However, when the Iridium communications satellite was hit by the defunct Russian Cosmos 2251 on February 10th, it turns out there was a “winner” in the satellite demolition derby (although I am using the word “winner” very loosely)…
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Another Satellite Collision Simulation

50 minutes after collision, over the South Pole (University of Southampton)
50 minutes after collision, over the South Pole (University of Southampton)

On February 10th, Iridium 33 and Cosmos 2251 became the first ever satellites to collide in orbit. The event was unprecedented. Quickly, visualization companies (such as AGI) created stunning 3D animations of the event unfolding, modelling the resultant debris. Now, there’s another animation available, this time from the University of Southampton Astronautics Research Group.

Watch the University of Southampton simulation »

I really like this version, as a) it is modelled by software called “DAMAGE”, b) you get a real sense of orbital speed vs. the vanishingly tiny chance that two satellites, of that size, could possibly collide, and c) you can almost hear the *BOOM* when contact is made (it is a fanciful *BOOM*, because in space no one can hear a satellite scream).

Let’s just hope those hundreds of pieces of debris don’t amplify the space junk problem up there…

Source: Flightglobal/Hyperbola

Visualizing the Iridium 33 and Cosmos 2251 Collision (Update: Video Added)

Less than a day after news of the unprecedented in-orbit collision between the active Iridium communications and defunct Russian satellites, the software company AGI has already carried out an analysis of the event. A detailed animation has been released depicting the velocity, angle of impact and statistical distribution of debris. Although the CGI is missing (I would have liked to have seen at least an explosion, shockwave and shards of twisted smoking metal. Come on guys, have a little fun!), it is a great visual aid for us to get a grip of what happened up there. To be honest I’m still blown away that this happened at all. There might be a lot of junk up there, but the statistical likelihood of this happening is still low.

You can also download the full-resolution AGI animation of the incident at their website…

Here are some visualizations of the impact in full 3D glory. All images courtesy of Analytical Graphics, Inc. (

A special thanks to Stefanie Claypoole at AGI for notifying me about this material.

It’s Not One-Way Traffic: Satellites Collide at 790 km

© David Clark
© David Clark

On Tuesday, at approximately 5pm GMT, two satellites made history. They became the first artificial satellites ever to collide accidentally in low-Earth orbit. The event happened between a defunct Russian satellite (Cosmos 2251, launched in 1993) and an active commercial Iridium communications satellite (Iridium 33, launched in 1997), destroying the pair. Now there’s a mess up there, pieces of debris threatening other satellites, possibly even the International Space Station
Continue reading “It’s Not One-Way Traffic: Satellites Collide at 790 km”