NASA Acting Administrator Janet Petro praised the achievement, emphasising its importance in strengthening American leadership in space and fostering growth in the national space economy.

Sunita Williams and Butch Wilmore have completed over 900 hours of research involving 150 scientific experiments and technology demonstrations during their extended stay on the orbiting laboratory.

America is eagerly awaiting the return of two astronauts who have been stuck on the ISS since last June. Here's who they are.