Friday, January 14, 2005

Taking Math for Granted

Every so often we see news items like today's story about landing a probe on Saturn's largest moon, Titan (an ESA, or European Space Agency project. I think they're from "Old Europe".....). We give it about 30 seconds of attention (a bit more if there are pictures) as it has become so routine.

I'm not a scientist, but believe I have a reasonable aptitude for some aspects of science so I started to think about this announcement today in a different light. To put it in perspective, a bunch of humans succeded in landing a 2.7 meter, 318 kg probe on an object 1.2 billion km away (the spacecraft actually travelled a distance of nearly twice that due to the indirect route it needed to take), a target with a diameter of a bit more than 5,000 km. I don't know how close it came to its intended landing spot on Titan, but I'll bet it was within 1000 km or so. The journey took a little more than 7 years. Along the way it passed through many conflicting and complementing gravity fields (using many of those for propulsion and course correction), and millions of pieces of space debris. My understanding is that due to the length of the journey (fuel considerations) very few if any earth-originated course corrections were initiated, other than at the very beginning and at the end. Think of a precise billiard shot over that distance, ricocheting off thousands of rails.

Add to that the adjustments needed to the received transmission frequncies due to the Doppler shift between the probe and the orbiting relay ship, Cassini, and that ship relative to the multiple receiving stations on earth.

I realize that most of the calculations were done by a computer; however, the programming for those calculations needed to be extremely precise. Ain't math wonderful.

Amazing...... Or as Matt would say, DEVELOPING..........

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