"We have to protect Earth" says astronaut
Japanese astronaut Kimiya Yui answered questions from children in Japan during his mission on board the International Space Station.
He told children: "When I was a pilot, it was the same in terms of flying above the ground and watching the beautiful woods and the sea. However, it was only when I became an astronaut that I realised how small Earth is.
"The Space Station goes around the Earth in around 90 minutes... you can tell how small the Earth is, and we have to look after it.''
He also said that studying and helping your parents clean up could help them become astronauts one day.
The Space station orbits 200 miles above our planet and Kimiya is staying for 5 months.