Frontiers are areas that have not been fully explored. There are very few frontiers left on Earth. However, beyond Earth there is a frontier bigger than we can possibly imagine-space.
Astronauts face many challenges when they spend even a short period of time in space. In the early days of space travel, missions lasted just a few days or weeks. Now, some astronauts live in space for up to six months at a time.
In Living and Working in Space, find out how astronauts prepare for and deal with the challenges of space.
Did you Know?
As the International Space Station orbits Earth once every 90 minutes, the Sun repeatedly appears and disappears behind Earth. This means crew members see a spectacular sunrise or sunset every 45 minutes.