The world will soon know if his gamble pays off.
Discovery is set to blast off from Kennedy Space Center at 3:49 p.m. EDT Saturday, the first launch of a space shuttle in almost a year and only the second since the Columbia disaster in 2003.
With storms expected, forecasters said there's only a 40 percent chance the shuttle will lift off tomorrow and the outlook is no better through Monday. However, weather is not NASA's only worry.
Whenever it flies, Discovery will be the only shuttle ever launched with a system officially classified as "an unacceptable risk," reports CBS News correspondent Bob Orr.
The seven astronauts say they are confident of Griffin's decision to go ahead, but hardly any astronaut ever publicly expresses fears before a launch.
"I believe we'll be as safe as we were on my other flights," said Steve Lindsey, Discovery's commander who has flown on three previous shuttle missions. "I haven't really seen a decision made that I didn't agree with."
But at least two top NASA engineers are up in arms over the shuttle going up at all, CBS' Drew Levinson reports. They've recommended postponing the mission so more work can be done to prevent damage from foam possibly breaking off during launch.
Faced with a 2010 deadline to finish building the international space station and end the shuttle program, Griffin wants to get the shuttles flying again and believes a delay now would create schedule pressure toward the end of the decade.
He has acknowledged, though, that he would likely shut down the shuttle program if there is another vehicle lost like Columbia or Challenger.
"Looking at the whole picture, I'm willing to take a little bit of programatic risk now — notice I did not say crew risk ... in order to prevent an excessive build-up of programatic risk later on," Griffin said recently. "This is in fact what they pay me to do."
But NASA said the foam poses no risk to the crew. If the shuttle is hit and the damage can't be repaired, Discovery's seven astronauts will scramble to the space station and await a rescue by the space shuttle Atlantis, reports Orr.
The board that investigated the Columbia accident faulted NASA three years ago for placing schedule concerns ahead of safety, squelching dissent and steamrolling over the concerns of engineers who worried that foam from the huge external fuel tank had hit Columbia. Fiery gases were able to penetrate the wing where the foam knocked a hole, causing the shuttle to disintegrate. All seven astronauts were killed.
This time around, NASA has aired its internal dissent publicly.
Bryan O'Connor, the space agency's chief safety officer, and chief engineer Christopher Scolese recommended at a meeting two weeks ago that the shuttle not fly until further design changes are made to 34 areas on the fuel tank known as ice-frost ramps. These wedge-shaped brackets run up and down the tank holding in place pressurization lines. Foam insulation is used to prevent ice from building up on the tank when it is filled with supercold fuel. Small pieces of foam have snapped off during previous launches.
At the meeting, Scolese wrote in a report that he signed, "I remain no-go based upon the potential loss of the vehicle."