Divya Delhi: Boeing's Atlas rocket experienced issues with its oxygen pressure-relief valve, causing a loud buzz. As a result, Boeing canceled their first manned launch on Monday night. The countdown was stopped two hours before liftoff as the two NASA test pilots were strapped into Boeing's Starliner capsule for a mission to the International Space Station. United Launch Alliance CEO Tory Bruno said an oxygen pressure-relief valve on the Atlas rocket's upper stage started fluttering open and closing, making a loud buzz. Bruno said the valve may have exceeded 200,000 lifespan cycles and must be replaced, delaying the launch until next week. If engineers can confirm the valve is within that limit, the launch team could attempt again Friday.After years of capsule issues, Boeing's maiden crew flight was delayed again.Boeing canceled its first astronaut launch Monday night due to a rocket valve issue. The countdown was stopped two hours before liftoff as the two NASA test pilots were strapped into Boeing's Starliner capsule for a mission to the International Space Station.United Launch Alliance CEO Tory Bruno said an oxygen pressure-relief valve on the Atlas rocket's upper stage started fluttering open and closing, making a loud buzz. Bruno said the valve may have exceeded 200,000 lifespan cycles and must be replaced, delaying the launch until next week. If engineers can confirm the valve is within that limit, the launch team could attempt again Friday