If you ever dreamt of being an astronaut as a kid, then you know that its no easy feat. The US space agency has revealed on its website all the requirements that need to be met by someone before they have a shot at going to space. The requirements to be a NASA astronaut have changed over the years to better align with the agency’s mission and values.

First, a potential candidate must be a US citizen. They also have to have a master’s degree in STEM field from an accredited institution — acceptable degrees include engineering, biological science, physical science, computer science, or mathematics.

On top of that, a potential candidate has to have at least two years of related professional experience after completing their degree, or ‘at least 1,000 hours pilot-in-command time on jet aircraft,’ the agency noted. NASA also emphasised the types of characteristics it’s looking for in its astronauts, including a skilled leader, a good communicator, and a good collaborator.

It’s not enough to simply be educated to be an astronaut, though, a candidate also has to be able to withstand the physical pressure of being in space. On that note, a person must be extremely healthy and able to pass the NASA long-duration flight astronaut physical, which tests agility, body co-ordination, eye co-ordination, and vision. Furthermore, NASA astronaut positions require a candidate to be of particular height and weight. To be a commander or pilot astronaut, you need to be 158cm to 190cm tall, and to be a mission specialist you need to be between 149cm to 193cm. In general, astronauts should weigh between 50 and 95 kilograms (110 and 209 pounds) and measure between 149.5cm and 190.5cm.