Astronaut Tim Kopra exercises in zero-G on the shuttle Discovery in September.
NASA astronaut Tim Kopra knows full well that the space shuttle may never fly after his next mission, currently scheduled for next September. But he also knows that in the space business, you can almost never say "never."
"I think we're all planning for this to be the last flight," he told me last week. "Of course, you never know until all the decisions are made."
NASA laid out its plans last month, just after Kopra wrapped up a two-month stay on the International Space Station. Those plans call for Kopra and four other astronauts who have had one round trip each on the space shuttle to go up for their second and final turn, under the leadership of veteran commander Steve Lindsey.
"It's a great crew, and I'm very thankful to be on this mission," Kopra said.
For now, Discovery's STS-133 mission represents the space shuttle fleet's last delivery call before its retirement. Those plans could change, however, depending on what the Obama White House decides to do with America's space program.
One of the options on the table is to extend the fleet's operating life for a few more flights, to cut down on the gap between retirement and the debut of next-generation spaceships such as NASA's Orion (or, for that matter, the crew-capable version of SpaceX's Dragon cargo craft). If the White House takes that option, Kopra's flight wouldn't be the last after all.
Kopra and his crewmates can't concern themselves with such big-picture decisions, of course. For now, the 47-year-old Army colonel's top priority is to get himself back in shape for the flight to come.
He's still recuperating from his time in space, which started with Endeavour's long-delayed launch in July and ended with Discovery's landing last month. When he arrived on the station, it marked the first time there were 13 people gathered together in one place in outer space - including the station's newly expanded expedition crew of six and the seven visitors from the shuttle.
Kopra said he didn't feel jammed in: "Not only was it not crowded with six people on board, it wasn't crowded with 13."
On the inside, the space station is now the size of a five-bedroom, two-bathroom house, and if you want to get around somebody in a hallway, all you have to do is float up toward the ceiling and fly over them.
"For me, life on space station was truly awesome," Kopra said. "I knew it was going to be a great experience, but I didn't anticipate that the quality of life was going to be so high."
Kopra's two months on the station may have ranked as one of the shortest "long-duration" flights in orbit, but the readjustment to Earth's gravity was still a challenge.
"The first couple of days were actually pretty challenging," he said. "My head felt like it was 50 pounds when I lay down to go to sleep. But the improvement is rapid."
He's still working on reports and debriefings from his time on the station. He's also going through a rigorous rehabilitation routine that includes physical workouts as well as mental coordination exercises.
"I feel like I've been in boot camp for the last three weeks," Kopra said.
Soon preparations will begin in earnest for the mission ahead. Kopra doesn't yet know what his duties will be as a mission specialist - but the fact that he's now an experienced spacewalker would put him in a good position to take on another extravehicular outing if necessary. Whatever his role turns out to be, Kopra can hardly wait.
"By the new year, we will definitely be in training," he said.