Boeing found that the valve failure of Starline spacecraft was caused by humidity


On June 2, 2021, at NASA’s Kennedy Space Center, Boeing Starline spacecraft prepared for the second unmanned orbital test flight
Tencent technology news on October 22, representatives of NASA and Boeing confirmed that they had successfully removed the two valves on the Starline spacecraft and transported them to the Marshall Space Flight Center for analysis. The test results show that the valve failure may be caused by humidity.
At the Marshall Space Flight Center, researchers conducted various technical inspections including CT scans of the two valves in order to find the cause of the valve failure that led to the test flight failure of the Starline spacecraft on August 3. Less than 5 hours before the launch countdown, during routine inspection, the staff found that 13 of the 24 valves controlling the flow of nitrous oxide through the spacecraft service cabin could not be opened and closed normally.
Because no reason was found on the launch pad, Boeing decided to return the Atlas V launch vehicle and Starline spacecraft to the assembly building. After more inspections and tests there, the engineers decided to “dismantle” the spacecraft and return it to the Boeing spacecraft processing building at the Kennedy Space Center. This eventually led to further dissection of the ship and the removal of several valves.
Michelle Parker, Boeing’s chief engineer in charge of space and launch, confirmed that Boeing already had a fairly reliable guess about what went wrong. During the 46 days of installation on the launch pad, when the valve was stuck, moisture must have entered the interior of the spacecraft. These moisture combine with oxidant to form nitric acid and start the corrosion process.
Parker said that there was heavy dew at the launch site in August. Although the spacecraft had taken into account the humid environment in Florida at the beginning of its design, there was physical evidence that humidity was still the culprit leading to valve failure. Boeing and NASA engineers now want to try to reproduce the corrosion reaction under similar test conditions so that they can identify the root cause and test whether the improvement is effective.
Boeing and NASA will advance this work at Boeing test sites in Florida, Alabama and white sands, New Mexico. John Vollmer, Boeing’s commercial astronaut program manager, admits that all this takes time. He said that Boeing’s current goal is to conduct an unmanned test flight of Starline spacecraft in the first half of 2022.
The official name of this mission is orbital flight test-2 (or oft-2). Boeing is performing the oft-2 mission at its own expense at a cost of US $410 million. Previously, the company’s first unmanned test flight of Starline spacecraft in December 2019 failed due to software problems. The company’s technicians and engineers spent a long time trying to repair the software after the oft-1 flight, but these new hardware problems suddenly appeared when they checked the launch day on the launch day in early August.
NASA hopes Boeing can start and fly the Starline spacecraft, so that it can have a second manned launch system, together with SpaceX’s manned dragon spacecraft, to allow astronauts to travel to and from the international space station. Assuming Boeing safely completes the oft-2, the company and NASA hope to have about six months to review the data and prepare for a manned test flight, Volmer said.
This will enable the Starline spacecraft to launch its first manned mission as early as the end of 2022. More realistically, the mission may not fly until early 2023. After this flight, NASA will prove that the Starline spacecraft is ready for routine and operable astronaut flights.
As part of the commercial astronaut program, NASA ordered six “post certification” missions from SpaceX and Boeing. SpaceX successfully completed the manned test flight mission in 2020, and will conduct the third commercial astronaut manned mission crew-3 for NASA on October 31, sending four astronauts to the international space station. The fourth and fifth missions are planned for 2022.
Steve stich, NASA commercial astronaut program manager, said the agency was negotiating more commercial manned missions for SpaceX (and possibly Boeing). He said details of the contract renewal could be announced in the coming months. Considering the latest issues discussed, SpaceX now seems likely to complete the initial six mission contracts before Boeing’s first manned mission. But Steve believes Boeing can do the same.
He said: “I believe Boeing will also succeed in the operation of Starline spacecraft. We will work hard to solve this problem, and then we will have the two space transportation systems we want.” (reviewed by Tencent technology / Jinlu)