Miami ? A sober internal investigation found no evidence to support recent assertions that several astronauts were impaired by alcohol shortly before blasting into space, NASA reported Wednesday.

“Where do these stories come from? Well, I don’t know,” said Mike Griffin, NASA’s administrator, who characterized the allegations as nothing more than “urban legends.”

“There are quite a number of things out there that are cited and are not true,” Griffin said. “This story is one of them.”

Bryan O’Connor, a former astronaut and NASA’s chief of safety and mission assurance, conducted the monthlong review of the claims included in a report released last month by an independent review panel.

That panel reported vague, anecdotal accounts of possible alcohol abuse by at least two astronauts in recent years.

One unidentified astronaut supposedly was drunk when he showed up for a shuttle launch. Another unnamed astronaut supposedly was inebriated before boarding a Russian Soyuz rocket for a flight to the International Space Station.

It turns out, O’Connor and Griffin said, that both accounts were based purely on rumor that could not be substantiated.

O’Connor said his team conducted 90 interviews and reviewed 40,134 records of all 94 shuttle flights and 10 Soyuz missions during the past 20 years and could find no evidence to confirm the assertions.

“Within the scope and limitations of this review, I was unable to verify any case in which an astronaut space flight crew member was impaired on launch day,” O’Connor said.