NASA let astronauts fly drunk on at least two occasions, an independent panel said in a report released Friday.

The report gave no names and did not say when the drinking occurred, how many astronauts were involved, or whether they were flying on the space shuttle, the Russian Soyuz spaceship, or aboard NASA's training airplanes.

NASA officials let them fly even after flight surgeons and fellow astronauts raised concerns that flight safety might be jeopardized, according to the report, done by a panel created by NASA after the arrest of astronaut Lisa Nowak in February on charges she tried to kidnap her rival in a love triangle.

In a statement Friday, NASA said the panel has not given the space agency details of the allegations. "As a result, NASA must independently determine the facts of the reported incidents," the space agency said.

Click here to read NASA report on astronaut drinking.

The panel said that astronauts and flight surgeons told the committee about heavy drinking by crew members just before flights. Also, the panel said alcohol is freely used in the crew quarters, where astronauts are quarantined at the Kennedy Space Center in the three days before launch.

Only four paragraphs of the 12-page report dealt with alcohol use by astronauts.

"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," the panel. "However, the individuals were still permitted to fly."

The panel said that NASA is not set up in such a way to deal with such problems.

"The medical certification of astronauts for flight duty is not structured to detect such episodes, nor is any medical surveillance program by itself likely to detect them or change the pattern of alcohol use," the panel wrote.

The panel recommended that NASA hold individuals and supervisors accountable for responsible use of alcohol, and that policies be instituted involving drinking before flight.

In another finding, the panel reported that flight surgeons' medical opinions were not valued by higher-ups. Several senior flight surgeons told the panel that officials only wanted to hear that all medical systems "were `go' for on-time mission completion."

The flight surgeons told the panel that higher-ups in NASA were notified of "major crew medical or behavioral problems," but that the flight surgeons' medical advice was ignored.

"This disregard was described as 'demoralizing' to the point where they said they are less likely to report concerns of performance decrement," the panel wrote. "Crew members raised concerns regarding substandard astronaut task performance which were similarly disregarded."

Fourteen astronauts, all but one with spaceflight experience, were interviewed by the panel, as well as five family members. All volunteered to take part in the review. In addition, eight flight surgeons were interviewed.