The Rosetta comet-chasing spacecraft of the European Space Agency, after travelling 4 billion miles in 10 years, has achieved its goal of a rendezvous with its target, agency officials say.
Now within 60 miles of Comet 67P/Churyumov-Gerasimenko, it will begin its studies of the icy body -- the first extensive, close-up examination of a comet - in preparation for putting a lander on its surface.
As the comet continues on its trajectory toward the sun, Rosetta will follow along, mission officials said.
"The key thing is we're rendezvousing and escorting right in alongside the comet for an extended period, for over a year," mission scientist Matthew Taylor says.
The comet and the spacecraft are currently around 330 million miles away from the sun and moving at more than 34,000 miles per hour.
First observed in 1969, the comet takes its name from its discoverers, Russian researchers Klim Churyumov and Svetlana Gerasimenko.
About 2.5 miles across, the comet's orbit around the sun, which takes it as far out as the orbit of Jupiter and as close as the orbit of Earth, takes 6.5 years.
In November, Rosetta will attempt to place a small lander known as Philae down onto the irregularly shaped comet's surface to make the most detailed examination ever conducted of the internal composition of one of these ancient wanderers of our solar system.
Philae will use a collection of nine instruments and a special drill to probe into the surface of the comet.
"It's really going to get down and scratch the surface to get the most pristine material that we can from the surface of the comet," Taylor says.
Comets like 67P/Churyumov-Gerasimenko are frozen leftovers of our solar system's formation some 4.5 billion years ago.
Remaining relatively untouched in all that time, comets could yield significant clues to that formation process, astronomers say.
That's why the $1.7 billion Rosetta mission has been designed to stay with the comet as it approaches Earth, conducting extensive scientific research in detail never attempted before, scientists say.
During that time the comet will start to warm up, emitting a streaming mixture of water vapor and dust that Rosetta will sample in a search for organic chemicals.
If they exist, they would be evidence of the theory held by many scientists that comets could have delivered the building-block elements needed to get life started on Earth.
