<a href="https://www.thenationalnews.com/future/space/2024/05/02/boeing-spaceflight-nasa-iss/" target="_blank">Boeing</a>’s much anticipated first manned flight of the <a href="https://www.thenationalnews.com/future/space/2024/04/18/boeing-capsule-placed-on-top-of-rocket-for-companys-first-astronaut-launch/" target="_blank">Starliner </a>CST-100 capsule hit another setback on Tuesday due to a technical issue with the rocket meant to carry the craft into space. The launch was cancelled about two hours before lift-off after a faulty oxygen relief valve was discovered in the Atlas V rocket built by United Launch Alliance, a joint venture between Boeing and Lockheed. On-board were two Nasa astronauts who were set for a two-week stay on the International Space Station, with the mission expected to show that the capsule was safe and ready for commercial operations. The mission is pivotal for Boeing as it seeks to rebuild its reputation after two crashes involving 737 Max 8 jets and a mid-flight <a href="https://www.thenationalnews.com/business/aviation/2024/02/06/bolts-missing-from-plug-door-that-flew-off-boeing-jet-us-agency-says/" target="_blank">door panel</a> blowout on a 737 Max 9 jet earlier this year. With the Starliner project, the plane-maker aims to turn the page and restore faith in its engineering prowess. United Launch Alliance has now set Friday as its target launch date. Dana Weigel, ISS programme manager at US space agency Nasa, told a media briefing after the mission was scrubbed that Boeing had “plenty of time to fly”. “With all of the mission prep and then the final scrub call … we're not in a rush to fly from a station standpoint,” she said. “We did clear our summer schedule intentionally to give us plenty of runway for the CFT mission.” Nasa awarded Boeing with a $4.2 billion contract under its Commercial Crew Programme, which aims to encourage companies to develop spacecraft that can deliver astronauts into space. However, the development of the Starliner CST-100 has been plagued with delays because of various technical issues over the past decade. Elon Musk's SpaceX, also part of the Commercial Crew Programme, has dominated the lucrative business and delivered eight crews to the ISS on behalf of Nasa since 2020. Even though Boeing lags behind SpaceX, a second ride to the space station would still be welcomed by Nasa as it would increase the space agency's access to the ISS. It would also reduce Nasa's dependence on a single spacecraft for missions, which would help in case one is grounded due to technical reasons. Boeing completed an unmanned test flight in 2022 when a Starliner capsule docked at the ISS and returned to Earth. The launch came about three years after a failed test flight in 2019 that foiled the craft's ability to reach the station due to a software glitch. Kenneth Bowersox, associate administrator of Nasa's Space Operations Mission Directorate, said delaying Tuesday's launch was the “proper action”. He said the oxygen relief valve regulates the pressure in the upper stage of the rocket. Maintaining it is important for the engines to run properly and take the crew into orbit. “We saw the self-regulating valve on the lock side had a bit of a buzz and so it was moving in a strange behaviour,” he said. “The flight rules had been laid out for this flight ahead of time with the crew at the launch pad. “The proper action was to take the scrub and United Launch Alliance team did a great job of assessing the data, talking through various options and put us into a scrub condition. “Now, we'll take the next day or so to look at the data and to recommend the next course of action.” The astronauts selected by Nasa to test the capsule are Sunita Williams and Butch Wilmore. Ms Williams, a retired Navy captain, has logged 322 days in space and completed seven spacewalks totalling 50 hours and 40 minutes. Mr Wilmore is a US Navy captain who has spent a total of 178 days in space. He was selected as an astronaut in 2000.