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Chris O'Meara
The space shuttle Endeavour rolls out on runway 15 after landing on her final flight at the Kennedy Space Center in Cape Canaveral, Fla., June 1, 2011.Chris O'Meara

Chris Hadfield, the first Canadian to walk in space and now the director of NASA's robotics program, is standing at a podium, ready to talk about the Canadian technology that will help ensure the safety of the next shuttle, Discovery, which is set to launch on Wednesday.

But first there is something he wants to do. "These are the seven people we killed 2½ years ago," he says, pointing at a picture of the crew killed when the Columbia shuttle exploded Feb. 1, 2003, scattering their remains and the pieces of NASA's shattered reputation over much of Texas.

Is there a catch in Mr. Hadfield's voice as he says this? Of course not. He is, after all, a former test pilot and Canadian Air Force colonel who has flown on two shuttle missions and worked as ground support for dozens of others, and so the words are spoken in a firm, fighter-pilot kind of voice.

At the same time, it's clear he wants to recognize those who lost their lives that day.

And so he says a few words about the men and women on STS-107: about Kalpana Chawla, who was born in a small town in rural India and was her country's first astronaut; and about Ila Ramon of Israel, son of a Holocaust survivor and the first Israeli in space. And the rest of the crew: mission commander Rick Husband; flight surgeon Laurel Salton Clark; specialist David Brown, who put himself through college by working as a circus acrobat; Air Force Lieutenant-Colonel Michael Anderson, one of the first black Americans to join the space program; and shuttle pilot Willy McCool.

In an interview later, Mr. Hadfield said the coming flight isn't meant as a tribute to the crew; it's a resupply mission for the International Space Station, he said, and a chance to see if the upgrades and changes made to the shuttle since the Columbia explosion work.

In other words, the "Return to Flight" mission is about doing just that: getting back to business.

"The purpose of a spaceship is to fly in space," he said. "We're not in the business of just dreaming about space flight, we're in the business of space flight."

At the same time, it is clear that Mr. Hadfield feels a deep sense of responsibility toward the Columbia crew. "It's true, we did kill them," he said in his blunt, no-nonsense way.

"And I'm just as responsible as anyone else here. It was not a random act of God, it was a sequence of incorrect decision-making. I made my own particular best judgment based on what I knew and I was wrong."

NASA, he said, "decided based on all our engineering judgment and knowledge that [the damage caused by a piece of foam]wouldn't be a problem. And we were wrong."

Former astronaut Marc Garneau, the first Canadian aboard a shuttle and now director of the Canadian Space Agency, said he believes some of those involved in the current mission will see a successful launch as a kind of tribute to the crew of the Columbia, a way of showing that NASA has learned from the accident that led to their deaths.

"I think once the shuttle is proceeding with its mission, there will probably be some comments made in that regard, that this means they did not die in vain," he said.

Like the Challenger explosion some 17 years earlier, the Columbia disaster transformed the shuttle program in an instant. Instead of a heartwarming story of man's ability to rise above his earthbound existence, it became a story about how NASA had become complacent about the risks. The next two years were spent in a frenzy of self-examination, as the agency tried to determine how such an event could have taken so many experts by surprise.

During that time, NASA has struggled to do three things: first, find out why the Columbia exploded when it was assumed to be resistant to damage; second, change its design so that nothing similar can happen again; and third, launch another shuttle to prove that the program can still accomplish its fundamental task of getting astronauts to space and back safely.

"Everybody wants to just get past this and get back to doing what they do for a living, which is send people into space and bring them back," said Iain Christie of Ottawa-based Neptec, whose company made the camera that will inspect the shuttle.

Unlike its sister ship Challenger, which blew up shortly after launch in 1986, the Columbia was destroyed just a few minutes away from its scheduled landing at Johnson Space Center in Houston.

A suitcase-sized piece of foam came off the shuttle's external fuel tank and hit the wing, leaving a hole -- which NASA didn't think was all that important at the time.

But when the shuttle was re-entering the atmosphere, Mr. Hadfield said, "a blowtorch of superheated plasma came screaming in through that hole and melted the wing," and the shuttle exploded.

NASA says it is satisfied it understands how the incident occurred and can prevent it in the future.

However, the shuttle must be sent up again to prove conclusively that it is safe to fly. And even after all the modifications -- including more than $1.4-billion (U.S.) spent to add heaters to the fuel tank to prevent a buildup of ice that could break off, and to change the way that the protecting foam is applied to the tank -- something unexpected could still put the shuttle in harm's way.

"There is no magic spaceship that is 100-per-cent safe," Mr. Hadfield said. "We know this is not a perfect vehicle or a vehicle without risk -- you can't ever say something is without risk. But NASA has decided that we understand the risks and that we are prepared to fly again."

The seven astronauts, however, will strap themselves in knowing that a recent task force report found NASA had failed to fulfill three of the goals set out after the Columbia accident.

Those goals were to: ensure that no ice or foam would come loose from the fuel tank; make sure that if anything did hit the shuttle, it wouldn't cause any serious damage; and if there were any damage, find a way for the astronauts to repair it before their return.

According to Mr. Hadfield, those three goals were virtually impossible to meet completely. "We can't take it to zero," he said of the chances that something might damage the shuttle. "We can try to minimize it, but we can't get rid of it completely. And if we do get some kind of damage, there are some holes that we simply can't repair once we're up there."

If something knocks a hole the size of a stop sign in the shuttle's wing, as the piece of foam did to the Columbia, "we can't just get out there and throw a bunch of Bondo on it," he said.

Mr. Hadfield and others in the space program say so much study and analysis has been done over the past 2½ years that this shuttle launch could be one of the safest in the aircraft's 25-year history.

"I am confident that this is the safest launch ever attempted," he said. "Far safer than a shuttle mission has ever been before."

In fact, he said, "I would be far more comfortable flying on this one than I should have been flying on the first two."

Even the members of the Stafford-Covey task force (otherwise known as the Independent Return to Flight Task Group, set up by the Columbia Accident Investigation Board and staffed by former astronauts) said that the shuttle was safe to launch, Mr. Hadfield said -- "safer than the ones they flew on."

Perhaps the biggest struggle for NASA since the Columbia explosion has been coming to grips with all the things that it suddenly realized it didn't know. According to Mr. Hadfield, "there have been over 10,000 incidents of debris hitting the shuttle during launch" over the 112 flights leading up to the Columbia mission. Why did a piece of foam cause so much damage that one time?

Paul Cooper, a vice-president at MDA Ltd. of Brampton -- which built the Canadarm -- says the piece of foam would have had to be exactly the right size and come off at exactly the right time to hit the shuttle's wing in such a way as to damage it so badly. The odds of that are almost impossible to calculate.

"I watched the footage of that foam over and over," Mr. Hadfield said, "and I decided that we didn't need to do anything."

So did most of the other NASA engineers who saw it.

Now, NASA says it has come as close as it can get to ruling out a similar accident. NASA administrator Michael Griffin -- a physicist and engineer -- said the shuttle will still be at risk, but at least the risk is known.

"Before, we were flying at risk of foam and ice," he said, but "we really did not know how serious it was. Now we know, and we hope it will be much less because of the changes we have made. But the risk will not be zero."

Safety measures

NASA's space shuttle program has been grounded ever since Columbia exploded while reentering the Earth's atmosphere on Feb. 1, 2003. The space agency has reviewed its safety procedure prior to Wednesday's scheduled launch of the space shuttle Discovery.

Return to Flight:

NASA has addressed 44 safety issues prior to flying the space shuttle again.

Key recommendations:

1. Redesign the external tank (ET). Remove foam "ramps" that cover bipod struts attaching the ET to the shuttle's nose. A piece of insulating foam hit shuttle Columbia's left wing, causing fatal damage.

2. Install an electric heater on the liquid oxygen feedline to prevent a build-up of ice.

3. Install two new bolt catchers to prevent pieces of 32 kg explosive bolts -- that release solid rocket boosters (SRBs) from the ET -- from becoming debris that could cause damage.

4. Strengthen Reinforced Carbon-Carbon (RCC), the nose cap and leading edges of wings.

5. Ground-based cameras at nine locations will provide sharp photographs

of the ET throughout launch and during separation.

6. Ascent cameras on the ET will film bipod area and underside of fuselage. Cameras are also on SRBs.

7. Install 66 sensors on each wing to measure acceleration and impact data, and a further 22 sensors to measure temperature during the climb to orbit.

8. Design and build a new laser-eyed inspection boom used by a robotic arm to inspect the shuttle in orbit.

Other recommendations in the return to flight plan:

Pictures of the shuttle in orbit will be taken from spy satellites.

Two-person closeout -- with digital photo record -- of the shuttle maintenance in areas sealed from further view or inspection.

Strengthen shuttle to withstand debris damage.

Avoid debris from ET hitting ship on liftoff.

Long-term goal - eliminate all debris from the ET.

Develop tile kit to repair holes in heat-shielding tiles and RCC during spacewalk.

Use the space station as safe haven for crew of damaged shuttle until rescue mission can be mounted.

Structure of shuttle.

External tank, Liquid oxygen: 549,407 litres at -183C.

Liquid hydrogen: 1,170,218 litres at -253C

Solid rocket boosters 499 tonnes of propellant. Fuel: aluminium. Oxidizer: ammonium perchlorate plus catalyst and binder.

A 15 metre extension to the robotic arm to allow repair of the underside of the fuselage.

Existing Canadarm.

Launch schedule to be dictated by available resources, rather than by management deadlines.

Sources: NASA, StaffordCovey Return to Flight Task Group

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Mathew Ingram

'Return to Flight' shuttle mission has much to prove