NASA confirmed Friday that astronauts have flown Space Shuttles and jet trainers while under the influence of alcohol.
The space agency is launching investigations and tightening its rules.
NASA says it does not yet know how widespread the problem is, but personnel report seeing at least two fellow astronauts under the influence boarding a Space Shuttle, and a T-38 jet trainer.
One was stopped from taking off his jet by a fellow astronaut, while other apparently drunk astronauts were not challenged, tested or stopped.
NASA officials promised an investigation.
"At this point what we're dealing with are allegations. And we have to find out what the ground truth is. That's our job," said Deputy Administrator Shana Dale.
Hard drinking was part of the astronaut culture in its 1960's heyday.
Drunk flying in the current program turned up as a panel looked into former astronaut Lisa Nowak's cross country meltdown.
NASA insists it's rare and isolated
"It really shouldn't paint a picture of the astronaut corps or of how we carry out human space flight at NASA," noted NASA Director of Flight Crew Operations Ellen Ochoa.
One longtime NASA expert notes that crews always parade to the shuttle on camera.
"None of them are stumbling, none of them are hiccuping none of them are just looking up at the sky. They all look very intent and very coordinated," pointed out NBC News Space Analyst James Oberg.
Starting this week NASA has formalized for the first time what was an unwritten rule violated at least twice maybe more often, no drinking 12 hours before taking off into space.
For now, however, NASA's focus will be on how drunk or over-tired astronauts were allowed to fly by colleagues who should have blown the whistle.