The Boeing launch already delayed Starliner spacecraft At least four more days will be lost, from next Tuesday to 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 targeting a launch from Pad 41 at the Cape Canaveral Space Force Station in Florida at 3:09 PM EDT each week starting Saturday, and setting up a docking station at International Space the following week Station. day, May 26, at 4:12 p.m
The astronauts had hoped to take off on May 6 for the Starliner’s first piloted test flight, but the countdown was canceled due to problems with an oxygen pressure relief valve in the Centaur upper stage of their Atlas 5 rocket.
United Launch Alliance
The Atlas 5, built by United Launch Alliance, was towed 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 propellant pressure system was noticed during the original countdown to launch, but it remained within safe limits for the flight. After the Atlas 5 and Starliner were rolled back to the VIF for oxygen valve replacement, managers decided to take a closer look at the helium problem.
The leak was discovered in the pipes that make up helium manifold No. 2, in one of four “doghouse” structures located around the outside of the Starliner’s drum-shaped service module. Each doghouse has four Orbital Maneuvering and Attitude Control (OMAC) thrusters and four small maneuver jets for the reaction control system.
Pressurized helium gas is used to push propellants to the rocket engines in each doghouse, as well as to four powerful launch abort engines that would only be fired in the event of a catastrophic problem with the Atlas 5 en route to orbit. soil.
Engineers tightened the bolts in a flange where the leak was detected, pressurized the pipes, and then ran tests to determine if the leak was still present. In the meantime, the launch was rescheduled for May 21.
But tests showed the leak was still present. Mission managers considered a range of options to resolve the problem, but they decided Friday to move forward to a May 25 launch possibility, pending additional data reviews and analysis to show that the leak, which is currently stable and within acceptable limits is not going to get worse. during the flight.
“Pressure testing showed that the flange leak is stable and would not pose a risk at that level during flight,” NASA said in a blog post. “The tests also showed that the remainder of the thruster system is effectively sealed across the entire service module.
“Boeing teams are working to develop operational procedures to ensure the system maintains sufficient performance and appropriate redundancy during flight. As that work continues, (mission managers) will take time in the coming days to review the data and procedures to make a final decision. before continuing the flight countdown.”
United Launch Alliance
Wilmore and Williams, both experienced Navy test pilots and astronauts with four flights to the station between them, flew back to the Johnson Space Center in Houston after the May 6 scrub to participate in additional flight simulations. They are expected to return to Florida next week.
The Starliner is one of two commercially developed crew ferries ordered by NASA following the retirement of the shuttle program in 2011. SpaceX won a $2.6 billion contract to develop the company’s Crew Dragon spacecraft and Boeing was awarded $4.2 billion to develop the Starliner.
NASA wanted spacecraft from different builders to ensure that the agency would still have a way to get astronauts to the space station even if a problem grounded a company’s ferry ship.
SpaceX launched its first two-person 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 trip of two men and two women. to low Earth orbit. A total of 50 people have flown into space aboard Crew Dragons.
Wilmore and Williams will be the first astronauts to fly aboard a Starliner after a series of technical issues, including major software problems during an initial unmanned test flight in December 2019, and corroded propulsion system valves that delayed a second unmanned test mission in May 2022.
Engineers encountered questions about parachute harness connectors and protective tape wrapped around wiring that posed a fire hazard if shorted. Work to resolve these and other issues has delayed the first test launch until this month.
