NASA and Boeing announced that Boeing's CST-100 Starliner commercial crew vehicle will push back the first mission with astronauts to early 2023. The team is currently addressing minor issues during an uncrewed test flight in May.
Why Boeing Starliner Delayed Its Schedule
The Crew Flight Test (CFT) mission, which won't take off until no later than February 2023, will include NASA astronauts Butch Wilmore and Suni Williams. After completing the Orbital Flight Test (OFT) 2 test flight in May, Boeing began preparations to launch CFT as early as this December.
The Starliner that will fly the CFT mission just has to be fine-tuned, according to data from the OFT-2 mission, said Mark Nappi, vice president and program manager for Starliner at Boeing. He said that the data showed a need for a minimal number of changes to the Starliner.
Nappi said that there was no hope of a CFT mission this year due to the fine tuning. He said that they had timetables that allowed for CFT to be completed by December of 2022. However, there were certain locations where the systems needed a little bit more development. They factored that into the plan, which moved them out by perhaps a month or roughly five weeks.
Root Cause of Failed Systems in the Boeing Starliner
The work in question deals with issues that arose during the OFT-2 flight, including the Orbital Maneuvering and Attitude Control (OMAC) thrusters. The OMAC shut down during the orbital insertion burn. Since the OMAC thrusters are in a service module that burns up on reentry and is not retrieved, Nappi first claimed that some debris-related conditions likely caused those thrusters to shut down. However, he later clarified that this is their best guess.
He claimed that they were uncertain about the origin of the debris. Overall, it appears to be the root cause. By inspecting the CFT vehicle and ensuring that there is zero debris in the system, they have successfully ruled that out.
According to Space News, the mission also saw the shutdown of several reaction control thrusters, which Nappi said was probably caused by low inlet pressures and could be fixed with a tweak in timing and tolerances in the software. Engineers concluded that high pressures in a thermal control loop observed during the flight were caused by filters that are unnecessary and may be removed. The VESTA guiding system on the spacecraft performed well but produced more data than the flight software could handle, prompting software modifications.
High Hopes in Boeing Starliner Launching in February 2023
According to Nappi, progress on the Starliner vehicle that will carry out CFT in Dec. 2019 is on schedule. It uses the same crew module as the OFT mission's initial flight . He said that they have strong plans to support that date in February, and that the crew module will be mated to its service module in November.
The first operational Starliner mission, which is anticipated to take place in the fall of 2023, is the company's ultimate goal, although he added that the timeframe was tight.
The valves in the service module for CFT won't be subject to any significant alterations by Boeing. Before an OFT-2 launch attempt in August 2021, the valves rusted as a result of atmospheric moisture reacting with nitrogen tetroxide propellant that leaked through the valve to produce nitric acid, which corroded the aluminum components of the valve. Boeing took action to dry out the valves in preparation for the OFT-2 launch in May. They also periodically opened the valves to check if they were working.
Alterations to the Boeing Starliner Before Launch
He stated, "We're flying that same configuration on CFT." He explained that because it is being used throughout the development and not after the vehicle is created, they have a decent short-term solution that they are slightly improving for CFT.
Boeing is still researching long-term modifications that would involve replacing the aluminum in the valves and sealing them off from moisture.
RELATED ARTICLE: NASA Boeing Starliner Launch Delayed; How Humidity, Corrosive Valves Hindered Plans
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