A ROCKET carrying the replacement crew for two NASA astronauts who have been stranded in space for nine months has finally launched. SpaceX's Falcon 9 rocket lifted off at 7.03pm ET from NASA's Kennedy Space Center in Florida carrying the four replacement astronauts. US astronauts Butch Wilmore and Suni Williams have been trapped on the International Space Station (ISS) for nine months and have had their journey home delayed a number of times. The two veteran astronauts were the first to fly Boeing's Starliner capsule to the ISS in June but issues with its propulsion system during the flight forced an extension to their trip. Originally planned as an eight-day stay, NASA deemed it too risky from them to fly home on the craft, which returned empty to Earth in September. Mission Crew-10 was initially scheduled to launch on Wednesday with its four astronauts, but a last-minute issue with the rocket's ground systems forced a delay. Now on the way, the Crew-10 mission is a long-awaited key step to bringing the stranded astronaut duo back to Earth. Williams and Wilmore are set to depart the station on March 19 after the replacement crew arrive on Saturday night. More to follow... For the latest news on this story keep checking back at The Sun Online Thesun.co.uk is your go-to destination for the best celebrity news, real-life stories, jaw-dropping pictures and must-see video. Like us on Facebook at www.facebook.com/thesun and follow us from our main Twitter account at @TheSun.