“Six minutes of terror”

If you’ve been following your geek news at CNN.com, you’ll know by now that Spirit — NASA’s latest land-roving probe — has successfully landed on Mars.

But what you may not know is just how utterly berserk those landings are. When Spirit hits the Martian atmosphere, it’s going 12,000 mph — about 15 times the speed of sound. The heat shield burns as hot as the surface of the sun (!), yet it does such a good job of protecting its contents that the probe itself, only a few feet away, never goes much above room temperature. A parachute opens up at 1,000 miles an hour, rapidly slowing the probe’s descent to about 250 miles an hour.

At that point, the probe drops down on a tether that is as skinny as a shoelace, to keep it a safe distance away when the lander’s retrorockets fire. With barely seconds to go before it slams into the ground — at nearly half the speed of sound — the lander snaps three quick pictures of the approaching terrain to help calculate its height and direction, and uses that information to instantly calculate the correct burn for the retrorockets. They fire, slowing the probe down even more, and the tether is cut, releasing the probe for its final drop to the surface. At that second, a crapload of airbags inflate, so the probe is covered with a cocoon of bubbles — which is good, because when it touches down it’s still travelling so fast that it bounces about four stories in the air. It bounces up to 30 times more before coming to a rest.

Here’s the fun part: NASA put together a video illustrating the entire process with superb CGI animation — it’s online here. (Go to the “Entry, Descent and Landing” section and click on one of the links.)

After you’ve seen that video, you simply cannot believe these guys can actually pull this off. It’s one of the most insane pieces of engineering I’ve ever seen in my life, just demented beyond description. They call the landing “six minutes of terror,” and I can see why. I can’t imagine how tense the landing room must have been, as they waited to find out if the probe would survive. Christ, I’m surprised the NASA guys aren’t all massive crystal meth addicts; I don’t know how else you’d survive the suspense.

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I'm Clive Thompson, the author of Smarter Than You Think: How Technology is Changing Our Minds for the Better (Penguin Press). You can order the book now at Amazon, Barnes and Noble, Powells, Indiebound, or through your local bookstore! I'm also a contributing writer for the New York Times Magazine and a columnist for Wired magazine. Email is here or ping me via the antiquated form of AOL IM (pomeranian99).

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