The loss of the Space Shuttle Columbia and its crew earlier this year has not dampened the pioneering spirit of would-be astronauts locked in a race to build their own manned launch vehicles. While the shuttle accident was an stark reminder of perils often overlooked in space travel today, competitors in the X Prize competition to put humans in space -- many of whom will ride inside the vehicles they're building -- maintain that their missions are still go.

"I think if anything, it's increased the amount of interest in our project," said Geoff Sheerin, leader of Canadian Arrow, one of two Canadian teams out of 24 groups vying for the X Prize.

"You have to understand that we already had Challenger on the books, long before this happened," Sheerin said. "So we had already something that we could point to and say, 'Yeah, things could go wrong.'"

In 1986, the Space Shuttle Challenger exploded during a Jan. 28 launch, killing the seven astronauts aboard at the time. Faulty O-rings in the shuttle's solid rocket boosters were later identified as the accident's cause.

But the X Prize efforts are much smaller, and often much simpler in design, than NASA's shuttle program or any other national space effort. Another X Prize entry, the SpaceShipOne project led by aerospace designer Burt Rutan of the company Scaled Composites, has already rolled out a launch vehicle, named pilot astronauts and is busy conducting flight tests high above Mojave, California.

The Scaled Composites flight plan calls for a high-altitude vehicle dubbed White Knight to carry SpaceShipOne up to a height of 50,000 feet (15,240 meters), where the spaceship then ignites a rocket engine to reach space. After about three minutes of weightlessness, the craft then reenters the Earth's atmosphere and glides down to a landing strip. An official date for the project's first space shot has yet to be released.

Although neither Rutan nor any of the four named SpaceShipOne pilots were available for comment, the aerospace designer has said the project's goal is to win the X Prize and build interest in private space travel.

"Our goal is to be the first private spaceship to fly private astronauts to 100 kilometers," he explained in a statement on the X Prize web site. "I hope our progress will inspire others to follow in our footsteps. We're going to space because that's where the view is."

Started by the X Prize Foundation in 1996, the X Prize will award a trophy and $10 million to the first group that sends a spacecraft-for-three 62 miles (100 kilometers) into the atmosphere, then repeat the feat two weeks later. The launch can be completed with one pilot and ballast in place of the two passengers, an X Prize spokesperson said.

Following the Columbia accident, most X Prize teams sent messages to the foundation reaffirming their commitment to the space endeavor. "The common theme through out all of theme is the importance, now more than ever, to develop private, safe and low-cost spaceships," said Peter Diamandis, chairman and president of the X Prize Foundation, in an interview.

Although the pilot selection methods of X Prize contenders vary from team to team, Canadian Arrow was the first to recruit astronauts from the general population, requiring only a $75 application fee and some paperwork. On June 26, Sheerin's team will announce the three people, chosen from hundreds of applications, who have enough of the right stuff to train for the Canadian Arrow mission.

Canadian Arrow's astronauts will have three main qualities. He or she will work well with teams to integrate into the 18-member Canadian Arrow group. Applicants should also "have a technical mind," though not necessarily technical knowledge. Finally, the successful applicant will be in generally good shape.

"If you fit any of those three things, then you're a pretty good candidate," Sheerin said.

The three successful astronaut candidates will train for a total of eight weeks, not necessarily all at once, between their announcement and the expected launch next summer.

"You don't have to quit your day job," Sheerin added. "We're hoping that the employer may, for this case, be able to make a special exemption."

The immense response to Canadian Arrow's call for astronauts shows there is still a large interest in space tourism despite the public failure of Columbia, NASA's oldest space shuttle. Part of the reason the Foundation started the X Prize was to kickstart the space tourism industry, much like aviation contests in the early 1900s helped get people in the air.

"I think Canadian Arrow's call for astronaut test-pilots is an innovative way to generate continued enthusiasm and interest," Diamanidis said. "It also reinforces the fact that this class of passenger space-vehicles are intended to fly the general public into space."

Diamandis added that there has been some financial fallout to the X Prize Foundation due to Columbia. The accident caused some sponsors concerned over the obvious risk to pull away from the project, forcing the foundation to seek other funding sources.

Brian Feeney, leader of the Canadian da Vinci X Prize effort, said his team conducted a project review following the Columbia accident, but made no changes in their craft's design and mission profile.

"It's as if we're designing an aircraft," Feeney told SPACE.com, adding that the prevailing mission outlook states that anytime you fly, you can lose the mission, but you can't lose the aircraft.

Today's modern technologies, from basic structural materials to thermal protection systems, make it viable for small-scale space vehicle projects without compromising safety, Feeney added. "The basic space shuttle design was laid out in the early 1970s, and a lot of things have changed since then," he said. "That system is sort of caught in a time warp."

The da Vinci Project will launch Feeney, riding aboard the Wild Fire spacecraft, into space from a launch pad suspended 80,000 feet (24,384 meters) above the ground by a helium balloon. Feeney believes his team would make the vehicle just as safe, even if the boss weren't flying, but he thinks his "character" helps.

"I'm not your typical astronaut," said Feeney, who has dyed his hair white three times during the competition. "I've never tried to change or conform to the norms."

The da Vinci team leader will undergo hundreds of hours of training leading up to the expected launch in 2004 from the skies above the Canadian province of Saskatchewan. The Canadian Defense and Civil Institute of Environmental Medicine, which has trained Canadian fighter pilots and astronauts, is putting together a program for Feeney as well. The team is also building a flight simulator with the help of three pilots who are on the team.

"A lot of your training is involved in when things go wrong, not when things go right," Feeney says. "For every our we sort of sit there watching the computer do something, we'll spend a hundred hours going through a host of things that are not going the way they should be."

Like Canadian Arrow, Feeney's team does strive to bring more attention to space tourism for the general public. "There's a small, if not possibly large, worldwide impact that will be groomed out of this over the decade to come," Feeney says.

But Feeney, who has had a lifelong fascination with space and made his first gunpowder in sixth grade, is also personally motivated. "This is just way too much fun," he said.

However, before humanity can go out and explore the universe in person, it will have to find a cheap way to transport people into space en masse. That's where the X Prize can make a galvanizing mark, pushing independent enterprises to take the initial steps of commercialized space travel despite the risk involved.

"There's risk in virtually everything you do, and you cannot mitigate it down to zero even by staying in your own home," said Michael J. Gallo, CEO and president of American X Prize competitor Kelly Space and Technology. "I think the draw here is that you're doing something that’s never been done before, something that's worth doing."

Based in San Bernardino, California and co-founded by Gallo and Michael Kelly, Kelly Space has been working since 1993 - before the start of the X Prize - to develop a reusable spacecraft. The pilot for its entry will be chosen from a pool the engineering and design firm works with regularly.

"But as for passengers, I know I want to go," Gallo said.

The thought of flying in a spacecraft not designed by the armada of scientists and engineers behind the NASA space program or the Russian Soyuz may be frightening to some, but clearly not for those chosen and those who will be chosen to fly the X Prize entries.

"For those who say 'no way', that's fine; they can wait until later. "We are opening a frontier that has a measured amount of risk. Pioneering isn't for everyone," Diamandis says. "But I can assure you that there are many people, including myself, who would love a chance to personally participate in the early days of commercial spaceflight."