Back on Earth, Kelly’s brother Mark became an invaluable part of the research. Mark is a former astronaut himself – indeed the Kelly brothers are the only siblings to have ever been in space. As Scott’s twin, Mark was ideal to be studied as a control alongside his brother to detect what changes there were in the latter’s DNA after his extended time on ISS. The results of the continued experiments conducted on the twins are still emerging today.
It is difficult to conceive the hardship of spending 520 days floating around in a 2,000-square-foot metal living space. You may well imagine that, after the initial excitement of lift-off, things might get a bit dull on the missions. However, there were quite a few incidents and surprises – not all of them pleasant – to keep Kelly and his fellow astronauts alert during their time spent on the ISS.