WATCH: Nasa astronauts prepare for US flights to space

Suni Williams has been a Nasa astronaut since 1998, and has flown two previous missions, including 322 days in orbit on the International Space Station, where she took a stuffed toy dog with her for company, according to the Nasa website.

Now she's been introduced as one of the crew of astronauts who will fly the first US piloted space flights since the Space Shuttle programme ended in 2011.

The commercial spaceships will be built by Boeing and SpaceX and are expected to blast off to the International Space Station in 2019.