The new Canadarm2, going aloft this week, is longer, stronger, more nimble than its famous predecessor. And it walks to work
in St-Hubert, Que.
It seems appropriate for the original Canadarm to be lying now in several pieces. After 20 years of stellar service, the off-world champion of the zero-gravity power lift is temporarily grounded on Earth—in Brampton, Ont., to be precise. In a sealed clean-room as big as an aircraft hangar, technicians at MacDonald Dettwiler Space and Advanced Robotics Ltd. wear unflattering hair nets and white lab coats as they meticulously refurbish an icon of national pride. At the same time, Canadarm’s heir apparent sits in the payload bay of the shuttle Endeavour at the Kennedy Space Center in Florida, folded up, bolted down
and scheduled to thunder off on its maiden voyage this week. A lot is expected of Canadarm2, which is bigger, better and stronger than its predecessor, says former astronaut Marc Garneau, now executive vice-president of the Canadian Space Agency. “It,” says Garneau, “absolutely has to work.”
The new robotic arm, technically known as the Space Station Remote Manipulator System, is a remarkable feat of aerospace engineering. It is designed to function in a hostile environment where temperature swings of 300° C occur frequently as it hurtles through space, in and out of direct sunlight, at eight kilometres per second. But do Canadians care anymore? Endeavour is scheduled to dock with the International Space Station on Saturday, April 21, Day 3 of the 12day mission. When it does, all three shutdes capable of docking with the orbiting research facility will have done so twice in the past eight months. News reports make scant reference. Obviously, leaving the planet has taken on the unmistakably stale air of routine.
The old Canadarm only adds to that perception, performing flawlessly as it has in more than 50 missions. But there is nothing routine about strapping seven human beings to two 20-storey rockets that, once ignited, are inextinguishable before all the explosive fuel is spent. From zero to 28,000 km/h takes just 8.5 minutes. Aboard Endeavour this time around will be Canadian astronaut Chris Hadfield, assigned to unpack and activate Canadarm2 during the first space walk by a Canuck. The mission is critical. “We have an extremely important role here,” says Garneau, echoing the agency’s oftenrepeated message. “If that arm doesn’t work, they cannot continue building the International Space Station.”
Oddly, after 15 years of research and development, the new arm looks a lot like the old one. Canadarm2, at almost 18 m, is just 2.4 m longer than the original, or a bit shorter than the average tractor-trailer speeding along the highway. Its two hollow booms, about as wide as a telephone pole, have a slightly larger diameter than the old ones. They are crafted from 19 layers of carbon fibre, each as thin and wobbly as a cookie sheet. But when bonded together, the overlapping lightweight
fibres fuse into a tube more rigid than steel. Each of the booms, joined at an aluminum elbow, ends in an identical “hand” that resembles sockets from a ratchet set. Four cameras—one at each end and on either side of the elbow—provide astronauts with their only view of what they are doing.
Not surprisingly, with youth comes flexibility and strength. The old arm bends and twists in six directions, like a human arm’s movements. But Canadarm2 has one more so-called degree of freedom for increased manoeuvrability. It also has four times the muscle, allowing it to move a fully loaded shuttle with either hand.
Astonishingly, this arm walks. Because the old arm is anchored to the shuttle, it has a limited reach. But Canadarm2 will be able to travel about the space station, hanging on to a dozen fixtures scattered about its surface. To move the arm, operators will fasten its free hand to a fixture nearby, then instruct it to let go of the first anchor. The arm can then cartwheel to the next fixture—moving, in effect, like a space Slinky.
But for the mechanical gymnastics to begin, Canadarm2 must survive the jarring forces it will encounter during the launch. The arm, folded in four equal lengths, is bolted to a Ushaped pallet in Endeavour’s hold.
On Day 4 of the mission, a shutde crew member will use the original Canadarm to hoist Canadarm2, still on its pallet, out of the cargo bay and fasten it to the exterior of the station’s American laboratory, called Destiny. Then, Hadfield and U.S. astronaut Scott Parazynski, suited up for their space walk, will step out of an air lock and into history.
Cocooned in their rigid space suits, the pair will clamber up the side of the lab module and attach power and data cables to link Canadarm2 to the station. Next,
Hadfield and Parazynski will undo eight one-metre-long bolts to free the new arm from its metal straitjacket. With the space walkers safely back inside the shutde, a space station crew member will issue the first commands to Canadarm2, readying it to step off its pallet.
After a few tests to limber up the arm on Day 5, the arm will receive
a command to grab a fixture on Destiny’s exterior. Canadarm2 will then step off the pallet to become an appendage of the U.S. module. Throughout the mission, the CSA will monitor the arm’s performance at its control centre in St-Hubert, Que. That centre, linked directly to Mission Control at the Johnson Space Center near Houston, will provide astronauts and NASA officials with technical support.
On Day 6, Hadfield and Parazynski are to go for another walk on the wild side, exiting Endeavour to reconfigure wiring on Destiny’s fixture and to disconnect the power-data cables on the pallet. On Day 7, the two generations of arms will work together in what CSA calls “the first robotic ‘handshake’ in space.” Hadfield will be at the controls of the shuttle arm when a space station crew member uses Canadarm2 to pass him the empty pallet. In not so much a handshake as a handoff, Hadfield will take the pallet into Canadarm’s grip and stow it in the shuttle’s cargo bay for its return to Earth.
Canadarm2 is the first of three components that make up Canada’s $1.4-billion Mobile Servicing System. The second is a movable platform scheduled to go up in March, 2002. Much like a railcar, the platform will roll along trusses that span the length of the station. Canadarm2 will be able to step off Destiny and onto the rig to be carted to a new work site. The third component has been nicknamed the Canadahand. “Hand” is an understatement—the 3.5-m-long robot actually has two arms and two hands. Technically known as the Special Purpose Dexterous Manipulator, Canadahand will sit at the end of Canadarm2, giving it the
The trusty old Canadarm will hoist its agile successor to its place on the side of the station
ability to perform intricate tasks, including manipulating objects as small as a book. Once it arrives in November, 2003, it will perform routine inspections of the station and carry out delicate maintenance tasks that otherwise would require hazardous space walks by astronauts.
n the same Brampton facility where the first Canadarm ever built is getting its gears re-lubed, technicians are assembling Canadahand. They are testing its software, using counterbalanced steel cables to support the arms to simulate weighdessness. A few keystrokes at a computer terminal awaken one of the robotic arms, causing it to glide smoothly—until it suddenly balks. “We’re still working some of the bugs out,” explains Aaron Hoag, Canadahand’s 26-year-old chief engineer. “That’ll be what we’re doing for the next six months.”
As impressive as Canadarm2 and its accessories are, the old arm still has a lot left in it. Spar Aerospace Ltd. in Brampton began work on the first Canadarm in 1975, completing the $ 108million project for the arm’s inaugural flight aboard the shutde Columbia in 1981. NASA later commissioned four more, resulting in $600 million worth of export sales. One was destroyed in the Challenger explosion in 1986.
In the ensuing years, Canadarm has successfidly placed new satellites in space, and plucked broken ones from orbit for repairs, notably the huge Hubble Space Telescope in 1993. The arm has proven versatile, once knocking ice from a vent that endangered the shuttle’s re-entry into the earth’s atmosphere, and another time nudging a bent, malfunctioning antenna into place. In December, 1998, Canadarm took part in the space station’s first assembly mission, mating the U.S. Unity capsule to Russia’s Zarya module. It continues to be part of NASA’s planning for future shuttle missions.
One often-asked question is whether the Canadarms are still Canadian. The answer, until last week, depended on how you looked at it. Spar in Brampton developed, built and delivered the Canadarms and Canadarm2 before the company imploded in an investors’ revolt in 1999. Just prior to the uprising, Spar had sold its robotics division to MacDonald Dettwiler and Associates (MDA) in Richmond, B.C., which named its new subsidiary MacDonald Dettwiler Space and Advanced Robotics Ltd. MDA, in turn, was controlled by Orbital Sciences Corp., headquartered in Dulles, Va. But last July, Orbital diluted its stake when MDA held a public share offering, with the stock trading on the Toronto Stock Exchange. That left Orbital owning about 52 per cent, but the majority of the board of directors was Canadian. Then just last week, the robotics operation was further Canadianized when Orbital left the scene, selling its remaining shares to a group of investors, including the Ontario Teachers’ Pension Plan Board, CAI Capital Partners and Co. II and the B.C. Investment Management Corp.
So what does the whole $ 1.4-billion project buy Canada? The right to send one astronaut to the station every three years for a tour of duty of up to four months. Canada also gets 2.3 per cent of the room designated for scientific equipment inside the non-Russian part of the station, plus access to a rack outside for exterior experiments. As for MD Robotics, it has parlayed its acquired Canadian expertise into more business, agreeing to provide components for robotic arms being developed by Japan and the European Space Agency for use on the station. Meantime, Canadarm2 will be in place just in time. The next shuttle mission to the space station, in June, requires the new arm to take delivery of an air lock for astronauts going for space walks. The pace of construction remains feverish, and the risk to human life is significant. Everyone involved just makes it look easy. E3
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