NASA URGED TO POSTPONE MOON, MARS MISSIONS

As space shuttle Columbia limped home on its troubled flight, NASA was urged to postpone grand missions to the moon and Mars and focus on cheaper, simpler programs closer to Earth. ``It can be argued that much of what humans can perform in space could be conducted at less cost and risk with robotic spacecraft - and in many cases we believe it should be,'' a White House panel said Monday in a report on the future of the US space program.

Two cherished space aims of the Bush administration - a permanent moon base and a manned mission to Mars - will have to wait until funds are available, the report said. This could be decades away.

But the National Aeronautics and Space Administration won high marks for its science missions, even on the Columbia flight that ended at Edwards Air Force Base, Calif., late Monday after its crew had problems with computers, weather, and a clogged toilet. The crew still managed to observe more than 80 celestial objects through an observatory in the shuttle's cargo bay.

In the panel's scenario, the space shuttle program, which has suffered frustrating setbacks including hydrogen leaks that temporarily grounded the three-ship fleet, would be partly replaced with unmanned, heavy-lift vehicles that could carry bigger loads into space at less risk.

This would help in building Space Station Freedom, which originally had been envisioned as the base for the moon and Mars missions, the panel said.

The station itself should be redesigned on simpler, less expensive lines, and should accommodate projects by partners in the European, Japanese, and Canadian space agencies, the report said.