Days after Indian-origin astronaut Sunita Williams and Nasa's Butch Wilmore's flight to space was scrubbed in the final hours of liftoff, the American space agency has postponed the date for the second time.

Following the scrub, the new launch date was announced to be May 10, however, as the rocket needs more work, the date has been further pushed to May 17.

"Following a thorough data review completed on Tuesday, United Launch Alliance, the rocket manufacturer, decided to replace a pressure regulation valve on the liquid oxygen tank on the Atlas V rocket’s Centaur upper stage.

The rocket has been rolled off the launch pad with the Starliner capsule atop.

The oscillating behavior of the valve during prelaunch operations, ultimately resulted in mission teams calling a launch scrub on May 6. After the ground crews and astronauts Butch Wilmore and Suni Williams safely exited from Space Launch Complex-41, the ULA team successfully commanded the valve closed and the oscillations were temporarily dampened.

"After evaluating the valve history, data signatures from the launch attempt, and assessing the risks relative to continued use, the ULA team determined the valve exceeded its qualification and mission managers agreed to remove and replace the valve," Nasa said in a blog post.

Meanwhile, Nasa added that Wilmore and Williams will remain in crew quarters at Kennedy in quarantine until the next launch opportunity. The duo will be the first to launch aboard Starliner to the space station as part of the agency’s Commercial Crew Program.

The United States is looking to certify the second spacecraft with orbital capabilities to launch and return humans to and from space. So far, SpaceX's Crew Dragon has been leading the commercial space race.

The Starliner spacecraft, named Calypso, can fly autonomously or be steered manually and is expected to rendezvous and dock with the space station on Wednesday.

Source: India Today