In the federal budget released this week, President Barack Obama calls for increasing NASA's funding by 2% while cutting its manned space flight program. If enacted by Congress, the cuts will likely end plans to return astronauts to the moon. Some claim these cuts will damage America's capabilities in science and technology, but the president's spending plan will likely boost both.

The manned space flight program masquerades as science, but it actually crowds out real science at NASA, which is all done on unmanned missions. In 2004 President George W. Bush announced a new vision for the space agency: a return of astronauts to the moon followed by a manned expedition to Mars. A few days later NASA's office of Space Science announced major cutbacks in its important Beyond Einstein and Explorer programs of unmanned research in astronomy. The explanation was that they "do not clearly support the goals of the President's vision for space exploration."

Soon after Mr. Bush's announcement I predicted that sending astronauts to the moon and Mars would be so expensive that future administrations would abandon the plan. This prediction seems to have come true.

All of the brilliant past discoveries in astronomy for which NASA can take credit have been made by unmanned satellite-borne observatories, and there is much more to be done. By studying the polarization of cosmic microwave radiation, we may find evidence of gravitational waves emitted in the first fraction of a second of the big bang. By sending laser beams between teams of satellites, we should be able to detect gravitational waves directly from collisions between neutron stars and black holes. By correlating the distances and velocities of many galaxies, we should be able to explore the mysterious dark energy that makes up most of the energy of the universe.

None of this involves astronauts. The cost of all these projects would be a few billion dollars—not cheap, but nothing like the hundred or so billion dollars for a manned return to the moon, or the many hundreds of billions of dollars for a manned mission to Mars.