Elijah Williams
Boeing’s launch already delayed the Starliner spacecraft is delayed at least another four days, from next Tuesday until May 25, due to ongoing work to resolve concerns about a small helium leak in the capsule’s propulsion system, officials said Friday.
Mission commander Barry “Butch” Wilmore and co-pilot Sunita Williams are now planning to launch from pad 41 at Cape Canaveral Space Force Station in Florida at 3:09 p.m. EDT a week from Saturday, establishing a docking on the International Space Station next day, May 26, at 4:12 p.m.
Astronauts had hoped to take off on the Starliner’s first piloted test flight on May 6, but the countdown it was canceled because of problems with an oxygen pressure relief valve on the Centaur upper stage of the Atlas 5 rocket.
United Launch Alliance
The Atlas 5, built by United Launch Alliance, was transported from the pad back to the company’s nearby Vertical Integration Facility, where the suspect valve was replaced and cleared for launch.
The unrelated helium leak in the Starliner’s booster pressurization system was noted during the original countdown to launch, but remained within safe limits for flight. After the Atlas 5 and Starliner were returned to the VIF for oxygen valve replacement, managers decided to take a closer look at the helium issue.
The leak was detected in the plumbing that makes up the No. 2 helium collector inside one of four “doghouse” assemblies spaced around the exterior of the Starliner’s drum-shaped service module. Each doghouse has four orbital maneuvering and attitude control thrusters – OMAC and four small reaction control system maneuvering jets.
The pressurized helium gas is used to push propellants into the rocket engines in each doghouse, as well as four powerful launch abort engines that would only fire in the event of a catastrophic problem with the Atlas 5 on the way to orbit.
Engineers tightened bolts on a flange where the leak was detected, pressurized the lines, and performed tests to determine if the leak was still present. Meanwhile, the launch has been rescheduled to May 21st.
But as it turned out, tests revealed that the leak was still present. Mission managers considered a number of options to resolve the issue, but decided on Friday to move toward a May 25 launch opportunity, pending reviews and additional data analysis to show that the leak, which currently is stable and within acceptable limits, it will not worsen. in flight.
“Pressure testing… showed that the flange leak is stable and would not pose a risk at this level during flight,” NASA said in a blog post. “The tests also indicated that the remainder of the propulsion system is effectively sealed throughout the service module.
“Boeing teams are working to develop operational procedures to ensure the system retains sufficient performance capability and appropriate redundancy during flight. As work proceeds, (mission managers) will take the next few days to review the data and procedures to make a final determination. before proceeding to the flight countdown.”
United Launch Alliance
Wilmore and Williams, both veteran Navy test pilots and astronauts with four flights to the station between them, flew back to Johnson Space Center in Houston after the May 6 cleanup to participate in additional flight simulations. They are expected to return to Florida next week.
Starliner is one of two commercially manned ships ordered by NASA following the retirement of the space shuttle program in 2011. SpaceX won a contract valued at $2.6 billion to develop the company’s Crew Dragon spacecraft and Boeing received US$4.2 billion for the development of the Starliner.
NASA wanted spacecraft from different builders to ensure the agency would still have a way to get astronauts to the space station even if a problem prevented one company’s ferry.
SpaceX launched its first two-man crew in 2020. Since then, the company has launched eight NASA-sponsored crew rotation flights to the station, three commercial research missions to the lab, and a privately funded two-man, two-man trip. women. to low Earth orbit. In total, 50 people flew into space aboard Crew Dragons.
Wilmore and Williams will be the first astronauts to fly aboard a Starliner after a series of technical failures that included major software problems during an initial unpiloted test flight in December 2019 and corroded propulsion system valves that delayed a second mission. test tube unscrewed in May 2022.
Engineers were faced with questions about the parachute harness connectors and the protective tape wrapped around the wiring that posed a fire risk in the event of a short circuit. Work to fix these and other issues has delayed the first pilot launch until this month.
