Washington, Aug 3 : Two NASA astronauts have safely returned to Earth from the International Space Station onboard a SpaceX Crew Dragon spacecraft, marking the completion of a historic flight called demonstration (Demo-2) mission. The Demo-2 test flight for NASA's Commercial Crew Programme has become the first to deliver astronauts to the space station and return them safely to Earth onboard a commercially built and operated spacecraft. SpaceX's Crew Dragon, carrying Robert Behnken and Douglas Hurley, splashed down under parachutes in the Gulf of Mexico off the coast of Pensacola, Florida at 2.48 pm EDT on Sunday and was successfully recovered by SpaceX. "Welcome home, Bob and Doug! Congratulations to the NASA and SpaceX teams for the incredible work to make this test flight possible," said NASA Administrator Jim Bridenstine. "It's a testament to what we can accomplish when we work together to do something once thought impossible. Partners are key to how we go farther than ever before and take the next steps on daring missions to the Moon and Mars." SpaceX CEO Elon Musk appeared super excited at the completion of the test flight as he congratulated both NASA and SpaceX on the accomplishment that marked the beginning of a new era in human spaceflight. "When space travel becomes as common as air travel, the future of civilization will be assured," Musk said in a tweet soon after the splashdown. Behnken and Hurley's return was the first splashdown for American astronauts since Thomas Stafford, Vance Brand, and Donald "Dekea Slayton landed in the Pacific Ocean off the coast of Hawaii on July 24, 1975, at the end of the Apollo-Soyuz Test Project. NASA's SpaceX Demo-2 test flight launched May 30 from the Kennedy Space Center in Florida. It was the first time that astronauts were sent into space from the US soil since 2011. After reaching orbit, Behnken and Hurley named their Crew Dragon spacecraft "Endeavour" as a tribute to the first space shuttle each astronaut had flown aboard. Nearly 19 hours later, Crew Dragon docked to the forward port of the International Space Station's Harmony module on May 31. Behnken and Hurley participated in a number of scientific experiments, spacewalks and public engagement events during their 62 days aboard the station. Overall, the astronaut duo spent 64 days in orbit, completed 1,024 orbits around Earth and travelled 27,147,284 statute miles. The astronauts contributed more than 100 hours of time to supporting the orbiting laboratory's investigations. The Demo-2 test flight is part of NASA's Commercial Crew Program, which has worked with the US aerospace industry to launch astronauts on American rockets and spacecraft. The goal of the programme is safe, reliable and cost-effective transportation to and from the space station. The completion of Demo-2 and the review of the mission and spacecraft pave the way for NASA to certify SpaceX's crew transportation system for regular flights carrying astronauts to and from the space station. SpaceX is readying the hardware for the first rotational mission, called Crew-1, later this year. This mission would occur after NASA certification, which is expected to take about six weeks. /IANS