[ExI] Rosetta zips past stone

[Damien Broderick]

Isn't this one of your toys, Amara?

from Melbourne AGE:

In a minutely choreographed operation, the $US1 billion ($1.23 
billion) unmanned probe Rosetta - launched in 2004 by the European 
Space Agency - came within about 800 kilometres of an unusual 
asteroid called 2867 Steins, a distance that is a hair's breadth in 
space terms.

Its goal was to get rare, close-up photographs and surface scanning 
of an asteroid, part of the intriguing debris left over from the 
building of the Solar System.

The Rosetta data is being streamed to antenna stations in New Norcia, 
Western Australia, and a NASA laboratory in Goldstone, California.

The first pictures of the flyby were expected to arrived at mission 
control in Darmstadt, Germany, around noon local time on Saturday, 
followed by data from other instruments.

"It will take approximately four weeks for all of the acquired data 
from all instruments to be down-linked," ESA said.

The encounter between Rosetta and the asteroid took place 360 million 
km from home as Rosetta zipped through the asteroid belt between Mars 
and Jupiter, on its way to a rendezvous with Comet 
67P/Churyumov-Gerasimenko in 2014.

Rosetta switched on 11 instruments to scan the rock as it flashed by 
at 8.6 kilometres a second, or 30,720 km/h, using an optical 
navigation system to keep automatically on course, ESA said in a live 
blog of the operation.

The spacecraft had been instructed to make a flip so it can get the 
best view of the asteroid and this caused a planned break in radio 
contact of around 80 minutes.

At about 2014 GMT (0614 AEST Saturday) the craft resumed signal 
transmission to the cheers of ESA engineers and technicians.

"We're extremely happy that it worked," said the mission's manager 
Gerhard Schwehm, sipping a glass of champagne after the announcement 
from the control room.

"It's a big relief. People can relax a bit now and everything seems fine."

The images and data from the deep space craft - which was launched in 
March 2004 from French Guyana, and is 402 million kilometres from 
Earth - have begun beaming back to earth.

Schwehm said the data must first be sent to antenna stations far away 
from Europe because of signal issues created by the present position 
of the satellite and the curvature of the earth.

The timing of the flyby ensured the asteroid would be illuminated by 
the sun, making it likely the transmitted images will be clear and sharp.

Experts will parse the data from the 4.6 kilometre-diameter 
irregularly shaped asteroid for keys that could help unlock some of 
the mysteries of the creation of the solar system.

"Dead rocks can say a lot," Schwehm said.

Rosetta is due to make a second asteroid flyby in July 2010, skimming 
past a 100 kilometre rock called 21 Lutetia.

The comet-chasing project was approved in 1993 and launched in 2004.

If all goes well, Rosetta will meet up with Churyumov-Gerasimenko in 
May 2014 and then send down a small lander, Philae, that will hook 
onto the comet's crusty surface and carry out nine experiments.

The European Space Agency is supported by 17 countries, including 
Germany, France, Ireland and the Netherlands. It cooperates with the 
NASA, the European Union, European national space agencies and 
international partners. It's expected that the ESA will become the 
space agency of the EU in the near future.

AP/AFP