More astronauts embark on first space missions later in careers

— -- If all goes according to schedule Wednesday, astronaut Barbara Morgan, 55, will become the second-oldest American and the oldest woman to make an initial flight into space.

Though Morgan's case is extreme, she's in good company. The average age when astronauts make their first flight and the average age of shuttle crews have been rising steadily since the mid-1990s, according to a USA TODAY analysis of NASA records.

Morgan was the backup to teacher Christa McAuliffe and has been waiting since shuttle Challenger exploded in 1986, killing McAuliffe and six crewmates.

Morgan is scheduled to launch Wednesday on space shuttle Endeavour. Only astronaut Karl Henize made his inaugural space flight later in life, in 1985 at age 58.

The analysis shows:

•The average age for when an astronaut makes his or her first flight on the shuttle has jumped from the late 30s in 1993 and 1994 to the mid-40s today.

•A shuttle crew's average age has increased from 40.7 in 1995 to 46.7 for this year's flights in June and August.

The analysis included only full-time astronauts that NASA counted as part of a shuttle crew. That excluded people such as John Glenn, who was not a professional astronaut when he made his second space flight in 1999 at age 77.

The rise in age mirrors the statistics at the birth of the shuttle program, when only the most experienced astronauts flew and many astronauts had been hired in the late 1960s during the Apollo era. The crew of the first shuttle mission that was not considered a test flight, in 1982, had an average age of 47.

Among the causes for the recent increase is the disintegration of shuttle Columbia in 2003, which killed the seven-person crew and grounded the fleet for 2½ years. Astronauts such as Morgan were forced to wait for a flight.

The aging trend is also due to the large number of astronauts hired in the mid-1990s, says Steve Lindsey, chief of the astronaut office. At the time, NASA thought the International Space Station would host seven-person crews by 2002. Instead, the station crew has stood at two or three people and will rise to only six in 2009.

"I've never seen an issue where age has affected how someone has performed as an astronaut," Lindsey says, but adds that rising age is "a concern" because as astronauts get older, they face a higher risk of health problems and are more likely to leave NASA.

Then there's morale. The average age at which an astronaut makes his or her first flight has been rising steadily, which translates to people being forced to wait a decade after joining NASA to fly.

The longer waits "are certainly not our intent and certainly not our desire, either," Lindsey says.

It's now common for a shuttle crew to include two astronauts older than 50. In the mid-1990s, one crewmember over 50 was unusual.

Dafydd Williams, 53, is scheduled to make up to three spacewalks on the Endeavor flight. Spacewalks, which require strength and endurance, are the most taxing activity astronauts can do.

"It probably will be a little bit more physically demanding now at my age than it would've been 10 years ago," Williams says. "It's also going to be exciting. … We should challenge ourselves as we get older not to have these expectations that we have to stop doing various things."

Some astronauts who've flown during different decades of life say that at a more advanced age, it's slightly more difficult to recover from the effects of zero gravity. They also say that when it comes to space travel, older can be better.

"My last (shuttle) flight, when I was 59 years old, I felt at my peak," says Vance Brand, 76, who made his first flight on the Apollo capsule at 44 in 1975 and his last flight in 1990.

At 59, he had more experience and know-how, making him feel "very confident," he says.

Joseph Tanner was 56 when he made two spacewalks on a shuttle mission last July, but he says he thought he had as much strength as he had on spacewalks earlier in his career.

The big difference, he says, was the adjustment to and from zero gravity. It took him an extra day to regain his appetite after reaching orbit, so he had to force himself to eat before his first spacewalk. After the shuttle landed, he needed more time to feel normal again, he says.

"It didn't seem to me like I bounced back as quickly," he says, but "nobody complained" about his work in space, so "I think my reputation is intact."

Astronaut Bill McArthur was 54 when he rode aboard a Russian Soyuz rocket in 2005 to spend six months on the space station. He got a sign that he wasn't as young as he used to be while rehearsing the liftoff.

"Being curled up in the Soyuz for several hours (before launch), my knees hurt," he said, describing himself and his crewmates as being "on the wrong side of 50."

On the other hand, living in orbit is a great cure for garden-variety annoyances of age, says John Phillips, who launched on the Soyuz in 2005 to live on the space station the day before his 54th birthday.

"That's one of the real nice things about space," he says. "The aches and pains of your feet and knees and ankles all vanish."

Contributing: William Risser