18 February 2009

Ablation cascade

Now there's something for WordMan™ to get excited about! Ablatus is the perfect passive participle of aufero, the Latin verb meaning "take away" (infinitive: auferre). In English, to ablate is to remove, to wear away, or to erode. An ablation cascade is an extraterrestrial event, analogous to a chain reaction, where the debris from a collision or other explosion spreads throughout the orbital domain causing massive destruction of spacecraft. One satellite goes "boom" and the bits hit another and it goes "boom" and the bits hit another and so on and so on. Though I suppose "boom" is the wrong term in the silence of space, I expect you get the idea. This thought was triggered by my favorite website, Astronomy Picture of the Day (aka APOD) and its story about the collision between Cosmos 2251 and Iridium 33 in low earth orbit above Siberia on 10 February. This is supposedly the first such occurrence of satellites colliding. It is amazing when you consider the vastness of space, even more amazing than submarines colliding in the ocean. An actual ablation cascade would render space travel impractical. But this event does remind us of the reality of space debris and its hazard to spaceflight. Thirty years ago a nutty rock band called Devo penned a lovely tune about a man who lost his girlfriend to falling space junk. (Skylab had recently broken up and its bits tumbled earthward.) Who knew how prescient they were?

Space Junk (G. Casale & B. Mothersbaugh)
She was walking
all alone
Down the street
in the alley
She never saw it
When she was hit by
Space Junk
. . .
It smashed my baby's head
And now my Sally's dead

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