Rosetta drops by, looking for rubble

Newspaper article from SMH 5 September 2008 – appendix to New Norcia story

An artist's impression of Rosetta's flyb-by of the asteroid Steins

An artist's impression of Rosetta's flyb-by of the asteroid Steins

AS WORLDS go, it is tiny, little more than a lump of rubble left over from the birth of the solar system. But the voyage to reach it has taken more than 4½ years.

Early tomorrow morning the European space probe Rosetta will sweep within 800 kilometres of an asteroid called Steins. The minuscule asteroid, which measures 4.6 kilometres across, orbits the sun between Mars and Jupiter, 360 million kilometres from Earth.

Just finding it had been an achievement, said John Holt, a former Telstra engineer who leads the team operating the New Norcia tracking station, near Perth, which is owned by the European Space Agency.

It will be New Norcia's job today to beam up the final commands, ensuring Rosetta is on course for the 8.6 kilometres-a-second fly-past. If all goes well, the station will begin receiving pictures beamed back by the probe over the weekend.

"Ours is the prime tracking facility controlling the mission," Mr Holt said. "We are the central link between the Earth and the spacecraft."

Rosetta is so distant that signals travelling at the speed of light take 20 minutes to arrive. "It is quite difficult just to estimate where the spacecraft is," he said. "To try to manoeuvre to within 800 kilometres of the asteroid is quite incredible."

Discovered in 1969 and named after a Latvian astronomer, so little is known about the asteroid that almost everything Rosetta observes will be new to science.

Astronomers believe this irregular-shaped body of rock will provide clues to how the planets formed more than 4.6 billion years ago. Steins may be a fragment of a larger asteroid shattered in a collision long ago.

Regardless of what Rosetta finds, Steins is just a stop-off on its 10-year voyage of discovery.

Launched in March 2004, its mission is to drop a 100 kilogram lander on Comet Churyumov-Gerasimenko in 2014.

This story by Richard Macey was found at: