NASA officials ponder the future

CAPE CANAVERAL, Fla., Feb. 22 (UPI) -- Space shuttle Endeavour has returned to Earth, leaving only four more shuttle flights in the program and leading NASA officials to ponder the future.

The shuttle and its crew, led by George Zamka, landed at 10:20 p.m. EST Sunday at the Kennedy Space Center, ending a 14-day, 5.7-million-mile mission to the International Space Station.

"We've come a long way in human spaceflight because of the shuttle's capability," Zamka said. "We've launched and retrieved satellites, we've done medical research and now we've built this huge space station. We're almost to the point of passing the baton from the space shuttle to the space station in terms of what our human spaceflight experience will be now."

Kwatsi Alibaruho, lead STS-130 space shuttle flight director, said even with so much left to do in the shuttle program's final four flights, he was making it a point to spend some time thinking about the subject.

"It's very easy to get into a routine, to lose oneself in the hustle and bustle of trying to get the work done," Alibaruho said. "But the shuttle is a unique spacecraft. I find myself thinking a lot about how I'm going to describe this time to my son when he's old enough to understand. There has never been an operational spacecraft like (the shuttle) before and all indications are that it will be some time before there will be one like it again."