Knowing that being an astronaut is difficult, but no one thinks it is so hard
The universe is an interesting mysterious world, but also full of dangers. So, going into space, astronauts have to go through a very complex process of selection and training.Flying astronaut in the world's largest swimming pool
The US Aeronautics and Space Administration (NASA) built a swimming pool larger than 10 times the Olympic swimming pool standard, to train astronauts in weightless conditions.