Stardust from dawn of time arrives

The spaceship Stardust is pictured in this artist's rendering. Picture / Reuters

LOS ANGELES - A space capsule loaded with comet dust landed back on earth last night, released by its mother ship after a seven-year, 4.5 billion-km journey to recover materials formed at the dawn of the solar system.

The Nasa Stardust mission, which will allow scientists to study comet samples for the first time, ended when the 45kg capsule landed in Utah 11.10pm NZT.

"We visited a comet, grabbed a piece of it, and landed here this morning," said Don Brownlee, an astronomy professor with the University of Washington who is principal investigator for the Stardust mission. "It was a real thrill."

Television images showed scientists and engineers in the control room at NASA's Jet Propulsion Laboratory in Pasadena, California, cheering and applauding both at landing and earlier when the capsule's two parachutes deployed as it roared across the western United States toward its target.

"This thing went like clockwork," Stardust Project Manager Tom Duxbury said at a news conference following the landing. "To see that thing in one piece on the floor of the desert is very moving."

Earlier, Nasa scientists and engineers at the remote military outpost were nervous but upbeat as they awaited the vessel's return, according to one Stardust team member.

"There is some tension," said Chris Jones, director of solar system exploration at Nasa's Jet Propulsion Laboratory.

"There are parts of the system that have never been used before and they represent the unknown."

Assuaging some of those concerns, the Stardust spacecraft severed the umbilical cables between it and the capsule as scheduled. One minute later, springs on the craft pushed the capsule away. It was expected to enter the earth's atmosphere at a speed of 46,440km/h, the fastest of any man-made object on record.

Stardust's mission, which began in 1999, took it around the sun three times and halfway to Jupiter to catch particles from comet Wild 2 in January 2004. The dust was captured by a tennis-racket-shaped space probe containing ice-cube-sized compartments lined with aerogel, a porous substance that is 99.9 per cent air.

The particles, most of which are expected to be a tenth as wide as a piece of human hair, became lodged in the aerogel.

Comets are thought to be leftovers from the process of planet formation, and scientists hope the dust collected by Stardust will give them clues about the origins of the solar system 4.5 billion years ago.

"Capturing particles from a comet as it whizzes by is a way of looking back in time," Jones said.

- REUTERS