Boeing’s anticipated foray into crewed spaceflight hit a snag Monday, when the aerospace giant had to call off the launch of its Starliner spacecraft due to a mechanical hiccup. The mission, destined for the International Space Station (ISS), was scrubbed because of a valve issue in the Atlas V rocket provided by United Launch Alliance (ULA), according to the Houston Chronicle.

The valve problem was detected in the rocket's oxygen system, prompting ULA to hold off on the flight to conduct additional evaluations. The relief valve, part of the second stage of the Atlas V rocket, showed unusual "buzzing," which refers to the valve opening and closing rapidly – a condition that if not addressed, could result in mechanical failure due to fatigue. Till now, the soonest the team would try another takeoff would be Friday from Cape Canaveral Space Force Station in Florida.

Boeing's erstwhile uncrewed flights are dwarfed by SpaceX's impressive tally of nine manned missions since 2014. This puts additional pressure on Boeing to break into the market dominated by the likes of Elon Musk's SpaceX, which has been at the forefront of private spaceflight. With NASA astronauts Barry “Butch” Wilmore and Sunita “Suni” Williams ready to board the craft, Boeing seeks to secure its position as a reliable transporter for the ISS missions – a goal underscored by the more than $4 billion in NASA funding it received for capsule development, as reported by The Hill.

Despite the setback, ULA CEO Tory Bruno reiterated that safety remains non-negotiable. “The crew was never in any danger,” Bruno told a news conference, and the delay was a precautionary measure. ULA would have proceeded with launch had the mission only carried a satellite, but with human passengers involved, they chose a more cautious route. Reviews of the valve cycling – that is, how many times it opened and closed, are underway to determine the next steps.

Boeing's Starliner is central to NASA's strategy to have multiple commercial vehicles ferrying astronauts, ensuring access to the ISS is not hindered by any single supplier’s technical issues. Boeing is now looking toward a resolution of the existing problem on the Atlas V as it anticipates a milestone crewed launch for the program.