NASA says it has found no evidence to support reports that astronauts were drinking before flying on the space shuttle and other craft.

"I've never seen anyone show up for work impaired," said Bryan O'Connor, chief of NASA's office of safety and mission assurance, during a press conference Wednesday. "If an astronaut shows up impaired … they can be replaced right up until launch day. Who would want to do such a thing?"

NASA Administrator Michael Griffin says he has never seen an astronaut show up inebriated for work.
(Associated Press)

NASA posted a review by O'Connor, himself a former astronaut, on its website Wednesday morning that disputed charges made by an independent committee in July. The panel, citing anonymous reports, said there had been incidents of alleged heavy alcohol use by astronauts.

"Interviews with both flight surgeons and astronauts identified some episodes of heavy use of alcohol by astronauts in the immediate preflight period, which has led to flight safety concerns," the committee's July report said.

"Alcohol is freely used in crew quarters. Two specific instances were described where astronauts had been so intoxicated prior to flight that flight surgeons and/or fellow astronauts raised concerns to local on-scene leadership regarding flight safety. However, the individuals were still permitted to fly."

O'Connor, in his review, said that while he could find no evidence to back up the claims, NASA should consider a drug and alcohol testing program for astronauts and other employees.

Doctors should play a stronger "oversight" role on launch day and accompany astronauts as they prepare for launch, O'Connor wrote. Astronauts should also limit their alcohol consumption in off-duty hours up to a year before a flight, he said.

NASA administrator Michael Griffin agreed with O'Connor and said he had never witnessed an astronaut show up for work drunk.

'I can't imagine risking my ticket.'—NASA administrator Michael Griffin

"I can't imagine risking my ticket," he said. The two specific allegations are not true "with a very high degree of confidence."

Griffin also rejected calls to force the independent committee to identify the anonymous sources who made the charges.

"I don't have that kind of power," he said. "We don't live in that kind of a country and I don't want to."

NASA began to examine employee health more closely after astronaut Lisa Nowak allegedly tried to kidnap a romantic rival for a shuttle commander's affections earlier this year.