Starliner has delayed again and its launch window may close soon

For a week before the launch of Boeing’s much-anticipated Starliner test flight on Tuesday, officials from NASA and the aerospace company said the spacecraft and its Atlas V rocket were ready to go. Their big concern, they said, was the weather, with frequent afternoon thunderstorms along Florida’s east coast.

Tuesday morning, a few hours before the launch window opened, the weather conditions along the coast looked pretty good. But Boeing had to erase the launch attempt anyway, citing an issue with a valve in the spacecraft’s reaction control system, which helps the vehicle maneuver in space.

Engineers from Boeing and NASA then spent Tuesday afternoon trying to determine the cause of the “unexpected valve position indications” in the spacecraft’s propulsion system. Presumably, they were trying to determine if these valves were actually in the wrong position, or if the readings were due to some kind of wrong sensor reading.

Engineers couldn’t come to a conclusion on Tuesday evening, and Boeing said it was canceling a possible launch attempt for Wednesday. In a statement, the company declined to say when it is targeting its next attempt and needs more time to investigate the issue.

“We’re going to let data guide our work,” said John Vollmer, Boeing’s vice president of commercial crew program and program director. “Our team has worked diligently to ensure the safety and success of this mission, and we will not launch until our vehicle is nominally running and our teams are satisfied that it is ready to fly.”

Although the next opportunity after Wednesday to launch Starliner presents itself this weekend of August 7-8, sources have told Ars that the spacecraft may have difficulty achieving that launch window. Company engineers will likely need more than a day or two to resolve issues.

Starliner does not have an infinite launch window, however. The first conflict comes at the end of the month, when SpaceX’s CRS-23 International Space Station supply mission is due to launch on August 28. There are only two mooring ports available for this type of mission on the station. Currently one is occupied by a Crew Dragon, and the CRS-23 Cargo Dragon will occupy the second port. While NASA expects a CRS-23 launch in late August, Boeing’s Starliner is expected to launch around August 20 in order to have enough time to get to the station and depart before Cargo Dragon arrives.

According to NASA’s current schedule, the CRS-23 will undock from the space station on September 30, opening a port for Starliner during the month of October. But there’s another complication: NASA has a high-priority science mission, Lucy, with a 21-day launch window that will open in mid-October. This mission will also fly on an Atlas V rocket.

United Launch Alliance requires a minimum of two or three weeks for final preparations for an Atlas V launch, so even if Starliner launched on October 1, it would likely take some time at Lucy’s launch window. Dropping some of that would be risky for the asteroid mission, which faces a delay until 2022 if it misses its window. It seems likely that NASA would prioritize the Lucy mission over the Starliner test flight.

The bottom line is that for Boeing, NASA, and the United Launch Alliance, it’s really important to try and get Starliner out of the pad before mid-August, otherwise the mission could face long delays.

Already 19.5 months have passed since an initial test flight of the Starliner resulted in a “high visibility close call” in which the vehicle was almost lost both shortly after its launch and shortly before re-entering the atmosphere. This prompted NASA to launch an investigation into Boeing’s safety culture and demand a major overhaul of Boeing’s flight software. Boeing also agreed to pay for a second test flight, at a cost of $ 410 million, out of its own resources.

After much effort, Boeing finally returned to the pad this week. After Tuesday’s clean-up launch, however, the rocket and spacecraft will now return to an integration hangar for more in-depth troubleshooting.