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U.S.: Spacecraft Set To Return Solar Particles To Earth

Though made of diamonds, sapphires, gold, and silicon, a sampling device on board a U.S. spacecraft is set to bring even more precious cargo back to Earth in a week's time -- bits of the sun caught during the probe's three-year journey. Named "Genesis," the spacecraft should swing by Earth on 8 September, releasing a capsule containing particles of solar wind. The capsule is due to come down in Utah. But as RFE/RL reports, the capsule will not be allowed a hard landing because the precious cargo could get damaged. Instead, in a dramatic maneuver, the capsule will be snatched, in midair, by a helicopter.

London, 31 August 2004 (RFE/RL) -- On 8 September, scientists should be able to study -- for the first time -- pieces of the sun.

Robert Walsh is a space sciences specialist at Britain's University of Lancaster. "To be able to grab a piece of a star, to be able to grab the material that's coming out from the sun, the material that flows from this huge body at the center of our solar system, and analyze those particles at first hand, is something very special, indeed," Walsh says.

Walsh says scientists are looking forward to examining the particles because 99 percent of our solar system, including the planets, originated from the sun. Only the remaining 1 percent came directly from interstellar space.
"The navigation is very accurate, the spacecraft has operated flawlessly, and I am confident that we'll have a nice, safe, quick and robust entry."

And getting actual samples of solar particles is much better than depending solely on astronomical observations. "We can understand what the sun is like by using spectroscopy -- we try to split up the portions of light that come towards us. But that's very different than actually trying to grab a piece and also be able to analyze it. We know a lot about the solar wind. We know a lot about the sun, and how the sun operates. But actually to get an idea of the material that comes out from the star is very special," Walsh says.

Solar wind is made up of a constant stream of small particles from the sun that shoot through the solar system. These particles are normally diverted from Earth by its magnetic field.

And that's a good thing.

"Thank goodness a lot of the particles don't actually reach us, because if they did, it would be very dangerous, indeed. We have the Earth's magnetic field, a sort of force field that protects us from many of the high-energy particles, much of them [containing] very dangerous radiation which would very much affect our living here on Earth. The atmosphere also absorbs some of these waves, as well. So you really have to go outside the Earth's atmosphere, outside the Earth's magnetic field, and take something like 'Genesis' and grab this material for yourself," Walsh says.

"Genesis" was launched in August 2001 and steered into orbit around the sun.

Don Sevilla is an engineer on the "Genesis" project at the Jet Propulsion Laboratory in the western U.S. state of California. He explains "Genesis'" special solar orbit.

"That is a point in space where the gravity of the sun and the Earth are balanced, and so a spacecraft can reside in that area using very little fuel. I designed the mechanisms, and when we do that kind of work, we ensure that it is the most reliable mechanism, since nobody can go service it," Sevilla says.

Upon reaching orbit, part of the "Genesis" spacecraft opened, exposing a device that resembled the petals of a large flower. The petals are made from wafers of ultra-pure diamond, sapphire, gold, and silicon. The particles of solar wind were captured by the wafers.

The sampling operation lasted three years before the capsule closed and "Genesis" was steered back toward Earth.

The examination of these solar particles should yield significant scientific discoveries, even though the total amount probably equals a few grains of salt.

Sevilla -- who is responsible for all recovery operations -- notes that bringing the samples back to Earth presents its own challenges. Instead of letting the sample-return capsule land on Earth via its parachute, the capsule and parachute will be snatched on their descent by one of two helicopters that will be sent aloft for the purpose.

"When we launched 'Genesis,' those solar wind collectors were strong enough for landing directly to Earth, rather than being caught by the helicopter. The problem is that after being exposed in space for a number of years, they are much more fragile, and we don't want them to break," Sevilla said.

The helicopters will be equipped with special hooks to grab the capsule's parachute as it floats to Earth. Stunt pilots have been chosen for the job, and many media outlets have found this quite amusing.

"All the talk of Hollywood stunt pilots is kind of a diversion by the media because it's so entertaining. The fact of the matter is these are professional pilots. They are artists in flying their aircraft in the air, and they happen to work a lot for Hollywood because they are available for hire," Sevilla said.

Sevilla says he can't wait for "Genesis" to return.

"The navigation is very accurate, the spacecraft has operated flawlessly, and I am confident that we'll have a nice, safe, quick and robust entry," he says. "I will be out there, being very busy to ensure that we capture it in the air reliably."

Walsh says he's impatient, too, "to learn what secrets of our origins the samples unveil."

"Actually, that really does go back to the origin of how life started, and how this sun-Earth system's delicate balance may actually have evolved to where it is right now," Walsh says.

The "Genesis" project represents the first such space mission since the "Apollo" astronauts last brought samples back from the moon more than 30 years ago.