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Movie pilots ready for capsule catch

Not since the Apollo missions of the 1970s has Nasa brought back extraterrestrial samples to Earth.

Now its Genesis spacecraft is set to end that dry spell by returning samples it has collected of the solar wind.

But when the capsule parachutes down to the Utah desert in September, it will be anything but a run of the mill landing, as Rachael Buchanan found out when she attended the final dress rehearsal in Utah.

It's 3.15pm and out on the white salt flats of the US Army's Dugway test range Don Sevilla once again raises his tiny binoculars and scans the cloudless skies.

Despite the blinding Sun there's a cold wind whipping across the endless Utah plains that bites through every layer of clothing and makes everyone's eyes tear up.

But Sevilla and his companions seem oblivious to the contradictory elements.

Every one of the assembled Genesis team stares up intently, awaiting the appearance of a helicopter and the start of this latest rehearsal.

This is sample return 21st-Century style. No gentle ocean splashdown - on re-entry in September, the Genesis capsule will head straight for this desert and even its two parachutes won't ensure a soft enough landing for the delicate cargo.

Swatting particles

So LA based scientists at Nasa's Jet Propulsion Laboratory have borrowed some tricks and personnel from their glitzier neighbours in the Hollywood hills.

Before the capsule hits the dirt, movie stunt pilots will snatch it from the sky using an 18ftt pole and hook suspended below their helicopters. Or at least that's the plan.

As the distant thwack of rotor blades signal the chopper's approach, Sevilla anxiously raises his binoculars again.

Come September, a successful mid-air retrieval will be essential. Genesis has spent the last two-and-a-half years in space, basking in the solar wind, and on board is the collector system his team designed.

"It's like very expensive fly-paper. The collectors are wafers of silicon, sapphire, gold and diamond, tiled over several square feet and the solar particles embed into these solid materials," Sevilla said.

"But our total collection is just a few micrograms, on the order of a couple of grains of table salt."

Herein lies the reason for the mid-air ballet - the samples are miniscule and the wafers extremely delicate.

Sign of success

There's a collector for each kind of solar wind (fast, slow and coronal mass ejection) with another two constantly exposed, tasting the overall flavour of the Sun.

A hard impact could shatter the fragile tiles, mixing up the samples.

Unlike the rest of the Solar System, the Sun has kept the same composition as the cloud of dust and gas from which our planets formed.

So despite its Lilliputian scale, this sample could increase our understanding of how our corner of the galaxy evolved into the diverse planetary bodies we see today.

In the skies above, the chopper drops its cargo, which freefalls momentarily, before the rectangular parafoil inflates; slowing the descent to a lazy 10 mph.

Seven thousand feet up, the chopper lowers its boom and moves in for capture. The pole scrapes over the top of the chute and the collapse of the canopy confirms the capsule has been snagged. The second success of the day.

Back on the ground in his sunglasses and Nasa flightsuit, Dan Rudert looks every inch the Hollywood stunt pilot. While the softly spoken native of Salt Lake City is surprisingly modest and appreciative of the unique opportunity he has been given, he is in no doubt why he and fellow pilot, Cliff Flemming, were picked for the job.

All weathers

"In a way this is a lot like a movie stunt. You get asked to do a lot of crazy things by directors - people grappling out of your helicopter; flying over buildings or cars that blow up. But this stunt is not fiction; it's the real deal.

"On 8 September the space capsule comes in on this day and this day only and you better be ready and able to catch it - you don't get another chance."

Both pilots make it look easy, but Rudert is very aware of how risky the manoeuvre is.

"You have to be at a pretty close proximity to make sure you get it on the hook. If I'm a little too high it can rip through the canopy. If I'm too low then I can hook it through the skids and get it up into the tail rotor."

They've all been at this since 1998, before the probe was even launched, and Sevilla is very happy with day's outcome.

"This was fantastic," he said. "We've tested it in all sorts of weather now, in high winds this afternoon and with it starting out of vision above the clouds this morning. So we have proved it can be done in most conditions."

But what about the pilots - is Rudert confident they can repeat this success in September?

"We'll see who is closest between me and Cliff but we'll catch it. Absolutely."

Posted by thinkum at May 10, 2004 01:39 PM