World's oldest and most experienced spacewoman is getting three extra months in orbit. NASA said, Peggy Whitson will remain on the International Space Station until September. The 57-year-old astronaut reached last November and was supposed to return to Earth in June. <br/><br/>But under an agreement between NASA and the Russian Space Agency, she will stay another three months and take advantage of an empty seat on a Soyuz capsule in the fall. This mission, her third, will now last close to 10 months.<br/> <br/>Scientists are eager to monitor any changes to her body, to add to the knowledge gained from retired astronaut Scott Kelly's recent one-year flight. The two men she flew up with in November France's Thomas Pesquet and Russia's Oleg Novitskiy will return in June without her.