Associated Press
This image provided by NASA shows a high angle view of the Cupola, backdropped against the darkness of space and Earth's horizon, and some components of the International Space Station.

NASA is again putting out a help-wanted sign for astronauts.

But why? The space-shuttle fleet has been consigned to history, NASA's program to develop a new orbital launch system shelved in favor of a scrum among private contractors to develop a reusable shuttle.

America's only firm appointment in space for the next decade is to continue sending an astronaut or two at a time to staff the International Space Station.

In such a climate, the downsizing of the astronaut corps by attrition is notable perhaps for how many have stuck with the space program: There were more than 150 in 2000, about 60 today. The last nine hires came two years ago and are still in training.

NASA's not saying how many astronauts it will take on in the new class. The basic job requirements — a bachelor's degree in engineering, math or science and three years of relevant professional experience — are fairly open-ended.

Those in the first class of astronauts knew they were flying with largely unproven equipment, but no shortage of national support. Those in the 21st class of space trainees in some respects face a less-certain career path.

Perhaps it's just as well that NASA won't pick them until 2013.