Europe launches probe toward comet landing

By David McHugh
The Associated Press

	AP An Ariane-5 blasts off from French Guiana yesterday.
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The Rosetta craft blasted into orbit from Kourou, French Guiana, aboard an Ariane-5 rocket. Two hours later the rocket's upper stage boosted the craft to the nearly 25,000 mph needed to escape Earth's gravitational field.

European Space Agency (ESA) controllers in Darmstadt then took command of the 3-ton craft — named for the Rosetta stone whose inscriptions provided the key to Egyptian hieroglyphs — and began bringing its systems to life, deploying its 105-foot solar panels.

The launch was more than a year behind schedule. ESA abandoned a January 2003 date after another rocket in the Ariane-5 family veered off course the previous month and had to be destroyed. Two launch attempts last week were put off, first because of high winds and then by a broken piece of insulation.

Rosetta's destination — in 2014 — is a comet called 67P/Churyumov-Gerasimenko, an irregular chunk of ice, frozen gases and dust discovered in 1969 by Soviet astronomers Klim Churyumov and Svetlana Gerasimenko.

Rosetta must loop three times past Earth and once past Mars to gain speed, using the planets' gravitational fields as "slingshots."

While Rosetta orbits the comet, its lander will try to touch down, using a harpoon and spikes to grab hold. The comet has a diameter of three miles at most, and therefore its gravity is very weak.

Scientists find comets interesting because they are considered to be much as they were when the solar system first took shape — unlike Earth and the other planets, which have undergone vast changes. But no one has been able to sink a drill in a comet and see what it is made of, as Rosetta's lander will attempt to do.

Scientists also believe that comets, which once pelted Earth, may have brought much of the planet's water, as well as compounds necessary to the formation of life, such as amino acids and substances based on carbon.

The lander will have at least a week's working life on the surface on its batteries, and up to six months if its solar panels can grab enough sunlight, Schulz said.

Like NASA's Pioneer and Voyager space probes, Rosetta will carry a message after its mission ends — in this case, the first three chapters of Genesis on a nickel disk, translated into 7,000 languages.

Copyright © 2004 The Seattle Times Company