NASA’s budget is $16.8 billion, about 0.6 percent of the total federal budget. Three fifths goes to human spaceflight, a third to science (for the planetary probes as well as space telescopes to explore the broader universe) and the rest to aeronautics.

The agency projects the new moon shot will run about $100 billion over the next decade. The Apollo program cost about the same.

This money comes from phasing out the shuttle and space station. President George W. Bush has retracted his earlier promise of a few extra billions, forcing a 20 percent cut in the science program.

Numerous missions have been canceled or put off.

NASA administrator Michael Griffin estimates that if the agency’s budget just keeps up with inflation, astronauts could land on Mars in the late 2030s.