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Shuttle's recovery given a shot in the Canadarm

When the Discovery blasts off from the Kennedy Space Center this spring, it will be a landmark event for NASA, eager to prove that the shuttle is safe after the Columbia disaster two years ago. But it will also be a shining moment for Canadians who have played a crucial role in the craft's return to flight.

The Discovery will employ a number of new features to help ensure that the events of Feb. 1, 2003, when the Columbia disintegrated on re-entering Earth's atmosphere, are not repeated.

One of those features is an "extension" to the famous Canadarm called the Orbiter Boom Sensor System. Using the sensors on board the boom, astronauts will be able to inspect the entire surface of the shuttle for damage, something not possible before.

"What we discovered is that you really needed about 50 feet of extra length to cover the entire orbiter," says Mike Hiltz, technical program manager for the boom project at MDA, the Canadian firm that designed and built the device at its robotics facility in Brampton, Ont.

The original Canadarm was also 50 feet (about 15 metres) long. Once in orbit, the Canadarm will be able to pick up the boom, giving it a total length of 100 feet (30 m), along with greater dexterity. Cameras and two sets of laser-ranging devices on the boom will give astronauts a 3-D view of their craft, allowing them to measure not only the size of any damaged region, but also the precise depth.

After a long investigation, the Columbia Accident Investigation Board concluded last year that foam falling off the shuttle's external fuel tank during launch damaged the leading edges of the orbiter's wings. When the shuttle later entered Earth's atmosphere, hot air flowed into the wing's interior, destroying the craft and killing the seven crew members on board.

The astronauts had no way to do a thorough damage inspection while in orbit. "Now, they'll be able to see the whole surface," Mr. Hiltz says.

The boom was shipped to Florida just before Christmas, and has recently been installed in Discovery's cargo bay. The launch is scheduled for May 12. "We're very excited," Mr. Hiltz says.

But it's not just hi-tech giants like MDA that are helping to make the shuttle space-worthy. Take Iceculture, for example. The family-run business based in Hensall, Ont., normally makes ice sculptures for weddings and corporate events. Last summer, however, it got a call from the National Aeronautics and Space Administration.

The agency needs to worry about ice because the liquid fuel in the external fuel tank is so cold that it can cause ice to form on the tank's surface. Pieces of ice that fall from the tank during launch could be just as dangerous as chunks of foam. So one of NASA's crucial tasks over the past two years has been to test how the leading edges of the shuttle's wings respond to ice impacts.

Engineers have been using enormous guns to fire blocks of foam and ice at a replica shuttle wing. But the density of ice varies tremendously, depending on the purity of the water and the amount of air trapped inside. (The milky-white colour of a frozen lake comes from the large amount of trapped air.) Pure ice, with no air, is the densest possible kind, so that was NASA's natural choice for testing a "worst-case scenario" -- to find out what size of ice chunks can do what kind of damage.

But finding an ice manufacturer that could reliably and consistently provide such pure samples, cut to precise specifications, proved difficult. "We weren't able to find anybody in the United States who could do that," says Matthew Melis, an aerospace engineer at NASA's Glenn Research Center in Cleveland.

One of the companies he had been speaking with told him about Iceculture, "and the rest is history," he says. "We formed a sort of partnership, with those guys making ice, and us shooting it. And we had great success with their ice over the last year."

The NASA contract was certainly a departure for Iceculture, started by Julian Bayely 16 years ago. "My wife and I started it as a hobby, making ice punch bowls for weddings," Mr. Bayley says. "And from that point on, excuse the pun, it snowballed."

Mr. Bayley, who runs Iceculture with his wife, two of his daughters and a couple of dozen employees, says the NASA project was "a challenge," but one that he tackled with enthusiasm. "We had to use 100-per-cent pure water, and the ice had to be cut to exacting measurements," he says. The finished product had to have "no scuffs, chips, cracks -- no blemishes."

And so they started producing disks and cylinders of precise sizes, ranging from a half-inch to six inches in length (about 1 cm to 10 cm), packing them in containers filled with dry ice (frozen carbon dioxide) to prevent melting, and shipping them to NASA.

Canada has played a prominent role in the shuttle program from the beginning, but the public often appears blasé about the missions. "I think a lot of people in Canada don't realize that you've played, as a nation, a great role in the 'return-to-flight' effort," Dr. Melis says.

Dan Falk is a science journalist based in Toronto.

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