Boeing's Starliner has seen many cancellations in its days. Most recently, the firm hoped to launch Starliner on August 3 in an attempt to dock with the International Space Station (ISS), but the mission was scrubbed due to a technical glitch. Now, engineers are revealing they may have pinpointed the cause behind the failed mission.
During a NASA teleconference held on Friday, John Vollmer, vice president and program manager of Boeing’s Commercial Crew Program, stated that it was time to return the rocket back to the factory. The ship has been resting in ULA’s Vertical Integration Facility for over a week.
Engineers have been trying to fix the 13 oxidizer valves that failed to open during the countdown to launch. So far they have succeeded in moving seven of the stuck valves by August 10 and nine by August 13.
Vollmer further explained during the teleconference that the specialists have “done everything we can on those,” and that Boeing “ultimately decided to stop and go back to the factory” where engineers can continue investigating the craft's malfunction.
The most likely root of the problem
The “most likely root cause” of the problem, added Vollmer, is that moisture somehow got onto the dry side of the oxidation valves. This would have produced nitric acid causing the 13 valves to get stuck.
Vollmer dismissed water splashing in from an intense storm that swept through the launch pad a day before the scheduled launch as the source of this moisture. He also added that it was unclear if a redesign was required or if preventative measures would suffice.
“We use Teflon seals that can withstand NTO [nitrogen tetroxide], which is a very corrosive oxidizer. We know there is permeation through that seal,” further explained Vollmer. This is why engineers will now “have to go back to see if ambient moisture was retained during assembly” of the craft or if some other cause is responsible for the stuck valves.