To catch some rays. This autumn, Nasa will attempt to catch in mid-air a canister containing rays of sunlight after the Genesis spacecraft jettisons it back towards the Earth. If the fragile cargo hits the ground in September it could scramble the results of the three-year, million-mile mission to collect samples of solar wind - and this is where the professional stuntmen come in. The space agency has hired two stunt pilots, including one who has worked on films including Die Hard 2 and Star Trek IV, to fly helicopters fitted with giant hooks to chase and catch the precious canister as it descends. Slowed by a series of parachutes the space cargo will eventually fall at about 10mph, giving the pilots just a few minutes to snag it.
There is no chance of a second take if it goes wrong, which is why the two pilots were seen being put through their paces in a training exercise over the Arizona desert last week.
Project manager Don Sweetnam describes the capture as one of the most challenging parts of the mission. "We must get the spacecraft to return to a tiny spot in the Utah desert and then snag it with a helicopter before it hits the ground." This will be the first space material returned to Earth since Apollo 17 visited the moon in 1972.
Launched in August 2001, Genesis has spent two years collecting solar samples while hanging at a point in space where the gravitational pull of the Earth and sun balance perfectly. Earlier this month it carefully folded away the tennis-racket style collecting arms, comprising wafers made from pure gold, sapphire and diamond, and headed for home.
"The material our collector arrays are made of may sound exotic, but what is really unique about Genesis is what we have collected on them," says Don Burnett, lead scientist on the project.
The solar particles will be mainly hydrogen, helium, oxygen and other trace gases. The returned samples will weigh less than a few grains of sand but will offer scientists the best opportunity yet to understand what the sun is made of, and so shed light on the development of the solar system.
