Other space experts said that the reports appeared to be credible and authoritative.

"I have no doubt that our two space experts will be able to get the gist of any information their space friends may send."

"Nobody in the space community is happy today," a Federal space expert said.

But several space experts said yesterday evening that the announcement might be in the nature of a long-term goal and research program.

Some space experts hold that robots are the best way to explore Mars.

British space experts say it could be ready in 40 or 50 years.

Some space experts think the shuttle might have carried a secondary payload as well.

But other space experts, looking to lessons of history, warned of failure.

"They haven't ruled out anything," said an American space expert, who spoke on the condition of anonymity.

The space agency is at a turning point, most space experts agree.