'Sun catcher' finally flies

Goodbye for now: Genesis leaves the Earth

It had to wait over a week but the Genesis space probe finally blasted off from the Cape Canaveral Air Force Station in Florida, US, on Wednesday.

Genesis will return a small but precious amount of data crucial to our knowledge of the Sun and the formation of our Solar System

Dr Donald Burnett, Genesis principal investigator

The spacecraft, which aims to collect charged particles from the Sun, lifted clear of the launch pad at 1213 EDT (1613 GMT). A camera on the outside of the Delta rocket gave a dramatic view of the climb into the sky.

Mission managers later reported the spacecraft to be in excellent health, with its power and temperature levels all normal.

Genesis should have gone up nine days ago. At first, the launch was scrubbed because of concerns over a pair of power converters in the spacecraft. Then, when the components were cleared for blast off, bad weather kept the probe on the ground.

Genesis has been designed to capture and return to Earth about 10 to 20 micrograms of the solar wind, the charged particles that stream away from our star.

'Rosetta Stone'

Researchers hope the project will help them answer some of the fundamental questions about the exact composition of the Sun and the birth of our Solar System.

The solar wind is made up of billions of tonnes of matter

"This mission will be the Rosetta Stone of planetary science data, because it will show us the foundation by which we can judge how our Solar System evolved," said Chester Sasaki, Genesis project manager at Nasa's Jet Propulsion Laboratory (JPL) in Pasadena, California.

"The samples that Genesis returns will show us the composition of the original solar nebula that formed the planets, asteroids, comets and the Sun we know today," he added.

Genesis will be the first mission to return a sample of extraterrestrial material collected beyond the orbit of the Moon.

Mid-air retrieval

To do this, the spacecraft must get to a position in space well beyond Earth's atmosphere and the magnetic environment that acts as a buffer against the solar wind.

Genesis facts

Launch - July 2001

Return - September 2004

Journey length - 32m km

Probe dimensions - 2.3m x 2m

Solar array wingspan - 6.8m

Mass - 636kg

Only when it reaches this location - about 1.5 million kilometres (930,000 miles) distant - can it start to collect particles in its bicycle tyre-sized arrays made of diamond, gold, silicone and sapphire.

On-board instruments will record other details about the wind, such as its speed, density and temperature.

Genesis will return its cargo to Earth in September 2004. A capsule containing the samples will parachute down through the atmosphere, where it will be grabbed in mid-air by a helicopter. The special retrieval will prevent the samples from being damaged by the sudden impact of hitting the ground.

Gas and dust cloud

The $209m mission should provide invaluable information about the solar nebula, the great cloud of gas and dust that gave rise to the Sun and planets more than 4.6 billion years ago.

The spacecraft has to get away from the Earth's magnetosphere

Scientists believe the surface of the Sun has preserved the composition of the nebula. So by studying solar wind samples collected by Genesis, researchers expect to get a picture of the evolutionary process that has led to the enormous environmental diversity across our Solar System.

"Genesis will return a small but precious amount of data crucial to our knowledge of the Sun and the formation of our Solar System," said Dr Donald Burnett, California Institute of Technology, Pasadena, who is principal investigator and leader of the Genesis mission.

"Data from Genesis will provide critical pieces for theories about the birth of the Sun and planets."

The arrays will catch just 10-20 micrograms of particles