Reports of drunk astronauts have been circulating in the media, but according to an employee survey released on Wednesday, crew members have never gone on space missions under the influence of alcohol. However, there was one isolated incident, when a former astronaut was seen impaired after apparently mixing a prescription medication and alcohol.

The survey clearly states: “All respondents reported never witnessing a crew member consume alcohol, on launch day, in the time leading up to launch. Overall, there is a high level of understanding of and knowledge of where to find the documented Space Flight Alcohol Use policy across both astronauts and flight surgeons. Comments emphasized that the (Space Flight Alcohol Use) policy is clear and being followed.” 31 NASA flight surgeons and 87 astronauts responded to the survey.

In response to the isolated incident mention earlier, the study says: “Medical personnel and management assessed the situation and determined there was no impact to mission flight readiness or risk to space operations. Further details are protected by medical privacy.”

Previous studies regarding astronauts’ mental health issues reported incidents of astronauts being drunk on a launch date or before flying a plane and also the incident regarding astronaut Lisa Nowak, who attacked a love rival in a parking lot at Orlando International Airport one year ago, which determined NASA chief Michael Griffin to order an anonymous survey regarding these reports.

The survey contained 65 questions designed to assess four main objectives: the relationship between astronauts and flight surgeons as defined by openness of communication, level of trust, and understanding of safety responsibilities; concerns with raising and responding to issues of flight safety and/or crew suitability for flight; knowledge and implementation of policies and procedures detailing astronaut performance and crew assignment and knowledge and implementation of space flight alcohol policy and determination if there was personal knowledge of a United States astronaut , on launch day, presenting a risk to flight safety due to alcohol use.