The word astronaut, which is formed from two Greek words, means 'star sailor'.
The word astronaut, formed from two Greek words, means 'star sailor'.
Only flights which reach an altitude of 100 km or more are considered space flights.
Only flights reaching an altitude of 100 km or more are considered space flights.
People who are chosen to become NASA astronauts have to complete a difficult training program which lasts twenty months.
People chosen to become NASA astronauts have to complete a difficult training program lasting twenty months.