Genesis gathered 10 to 20 micrograms of bits of solar wind during its three-year mission, the first cosmic materials ever returned to Earth from beyond the Moon.

Scientists had hoped the microscopic particles from the solar wind would help them understand how the sun and planets were formed, but NASA officials said it was too soon to know what if anything could be retrieved from the damaged capsule.

The capsule careered into the ground at 310 kilometers (193 miles) per hour, hurtling past the helicopters that had planned to grab it in midair by latching onto the parachutes, said Chris Jones, director for solar system exploration at NASA's Jet Propulsion Laboratory.

"We have the samples, they are on the ground. There is still hope for a science result from this mission," Genesis mission director Don Sweetnam said.

NASA television images showed the saucer-like capsule's dramatic tumble as it twirled rapidly toward the western state's desert.

The capsule struck the Earth so hard that half of it was lodged the in the ground, where it was stuck at a 10-degree angle, said flight operations director Roy Haggard, who was aboard one the helicopters that was supposed to grab the craft as it fell.

"It appears that the science canister had been breached a couple of inches," he said.

The capsule entered Earth's atmosphere at 1555 GMT.

If all had gone according to plan, a stabilizing drogue parachute would have opened 33 kilometers (20 miles) above ground, followed shortly by the main parachute. In the end, neither opened, the National Aeronautics and Space Administration said.

Two helicopters, each with a crew of three, were in place with a six-meter (18-foot, six-inch) pole with a large hook on the end to snag the capsule as it plummeted through the sky.

Hollywood stunt pilots hired by NASA had been practicing since August 23 to keep the capsule from hitting the ground and damaging the solar samples, but they never got a chance to execute their aerial acrobatics.

"The capsule has suffered extensive damage. It's broken apart, sitting there on the desert floor," Jones said.

"We have no safety concern for the public."

The 494-kilo (1,000-pound) spacecraft used hexagonal wafers of silicon, gold, sapphire and diamond to capture 10 to 20 micrograms of the invisible bits of solar wind.

While some scientists try to figure out what went wrong, others will scramble to recover at least some of the precious shipment.

The samples were the first returned to Earth from beyond the Moon, and the first of any kind since the last Apollo mission to the moon in 1972.

On its 260-million-dollar mission, the Genesis spacecraft travelled three years and 32 million kilometers (20 million miles) to capture atomic bits of solar wind that NASA hopes will help scientists understand what the sun is made of and how the solar system began.

Genesis was launched in August 2001 and sent to a spot in space where the gravitational pulls of the sun and Earth balance each other.

That gave Genesis an uninterrupted view of the sun away from Earth's magnetic field, which disrupts the solar winds.

The wafers were to be sent to the Johnson Space Center in Houston, Texas for study.

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