Monday, November 28, 2005

The Falcon has landed

It now appears that the Japanese Hayabusa space craft successfully landed on the asteroid Itokawa, took a sample, and lifted off again. If all goes well, the craft will return to Earth with a smidgen of space dust two years hence.

Itokawa is a potato-shaped chunk of rock about the size of a football stadium (with parking lots). Its orbit is not all that different from the Earth's, as you can see from the diagrams here.

But let's get a better fix on the scale. Let the Sun be represented by a basketball on the 50-yard line of a football field. Then the Earth would be a pinhead on the home team's 20-yard line. Right now, as Hayabusa journeys along with Itokawa, the asteroid is on the opposing team's 22-yard line, and far too small to be visible on this scale -- say, the size of a big molecule.

Engineers on the pinhead Earth hurled a box of instruments on a two-year journey, chasing and catching up to the asteroid. From the pinhead Earth they now control this complex sampling operation more than half a football field away (15 minutes by radio signal) the first ever that -- if successful -- will return to Earth with material from a celestial object other than the Moon.