Then in August, Lockhart replaced rookie pilot Gus Loria when Loria was forced to remove himself from the crew because of an injury he sustained in an accident at home. Loria also remains an astronaut and his colleagues remain hopeful he can be assigned to a future flight.
Neither Pettit nor Lockhart are particularly happy about the situation, but it also wouldn't be fair to call them reluctant astronauts.
Pettit's story
"These kind of crew switch outs are always a double-edged sword in that you feel saddened for the person that was replaced, but at the same time it's a good opportunity for you," Pettit said.
A rookie, Pettit is to serve as science officer for the Expedition Six crew, which includes commander Ken Bowersox and Russian cosmonaut Nikolai Budarin.
The trio is to spend the next four months or so working aboard the International Space Station.
Unfortunately for Pettit, all of the clothing and food selected by Don Thomas for his stay aboard the outpost already has been delivered to the station during earlier shuttle missions.
Fortunately, Pettit can fit into Thomas' clothes -- and since both men share the same first name all of the personalized clothing has the correct moniker sewn into the fabric.
Back on the down side, Pettit is a loyal coffee drinker and Thomas isn't, so Pettit is using almost his entire allowable weight and volume for personal effects to carry a four-month supply of java into space.
He learned of his promotion to prime crew from Bowersox while they were all training in Star City near Moscow.
"There's no hard feelings from Don Thomas toward Don Pettit," Bowersox said. "When you want to do something that badly, you can imagine the shock. To be so close, four months away."
As backup, Pettit had been training for the long duration stay all along.
"In the back of your mind you realize the purpose of the back up crew is to take over in the event something happens to a prime crew member, but the likelihood of that happening is pretty small. Still it's a possibility," Pettit said.
"I trained as a back up with the mindset that I was going to fly. So I treated back up training very seriously," Pettit said.
Lockhart's story
Unlike the Expedition Six crew, the STS-113 shuttle crew didn't have specific backup trainees in the pipeline, but there was a plan in place.
When it was decided that Loria wouldn't be able to fly, chief astronaut Charlie Precourt turned to the pilot who had most recently flown aboard Endeavour.
Lockhart was Endeavour's pilot during the June shuttle mission that carried the Expedition Five crew of Valery Korzun, Peggy Whitson and Sergei Treschev to the station.
He and his crewmates were at the Marshall Space Flight Center in Alabama a couple of weeks after landing when Precourt called Lockhart on the phone and asked the veteran pilot if he was free for the next couple of months.
"When the astronaut office calls and says 'What does your schedule look like?' you basically say it's open and I can do what ever needs to be done," Lockhart said.
That initial phone call came on a Thursday, Lockhart remembered. The formal invitation to join the STS-113 crew followed the next day, and on that next Monday he was in a simulator at the Johnson Space Center in Houston training for the flight.
"It came really quick," Lockhart said. "I realize that I happened to have the right set of skills and just happened to be in the right place at the right time, and I'm honored that NASA would select me."
Lockhart said Loria was a class act in dealing with the situation.
"He didn't have to bring me up to speed on a whole lot of things. He was really gracious about letting me use his crew notebook, which was extensive and very well written out and really gave me a lot of insight into the thinking of how the crew operated," Lockhart said.
Given that this is his second spaceflight, Lockhart said he might be a little more relaxed on this mission, which also will probably give him a chance to be a little more nervous. But he's no less ready to fly.
"We're flying the same shuttle, the same type of mission where we use four crewmembers to bring up three, we're doing three spacewalks, I'm the pilot again -- all of these being the same meant that I could just fit right in."
Even the right-hand seat on Endeavour's flight deck is still at the same height Lockhart left it when he departed the shuttle after its landing in June, he said.
"If I just keep my head straight and stick to what I'm supposed to do, I know that we'll have a good flight and come back successful," Lockhart said.
Nothing new
Replacing prime crew members with backups is nothing unusual for NASA, but it remains a fairly rare event considering the number of people involved during the past 40 years.
The first such occurrence goes all the way back to Project Mercury when Deke Slayton was replaced by Scott Carpenter in 1962 because of Slayton's now infamous irregular heartbeat. Slayton was later cleared of his medical concern and flew the 1975 Apollo Soyuz Test Project mission.
The 1966 deaths of Elliott See and Charles Bassett in T-38 jet crashes forced NASA to replace them with backups Tom Stafford and Gene Cernan.
While crew assignments were juggled around for various reasons throughout Apollo, the most famous case of a last-minute astronaut replacement came in 1970 when Tom Mattingly was replaced by Jack Swigert just days before launch of Apollo 13.
But the emotional scenes in the Ron Howard film "Apollo 13" when the news was broke to the Mattingly character pale in comparison to what happens for real, Expedition Six commander Bowersox said.
"The emotions and the reality are much stronger," Bowersox said. "I had trouble sleeping before it happened because I was so worried about which way we should go, and what was right and what was wrong, and the best way to handle it."
Crew replacements in the shuttle era continued, whether because of medical reasons, deaths or what could be most diplomatically called "office politics".
Examples include John Blaha flying as pilot because of the death of David Griggs in 1989, or David Hilmers flying because of the death of Sonny Carter in 1991.
advertisement
