US astronauts were allowed to fly while drunk at least twice, a review panel set up by space agency Nasa has found.

The panel was created to look at health issues affecting Nasa crew members after astronaut Lisa Nowak was arrested on kidnapping and assault charges.

The drunk astronauts were allowed to fly even though colleagues had raised concerns about safety, the panel found.

The panel also said it found evidence of heavy use of alcohol within the 12-hour pre-flight ban on drinking.