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Boeing’s Starliner spacecraft sits atop a United Launch Alliance Atlas V rocket May 7 after its scheduled Crew Flight Test launch was scrapped.
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The target date for the long-awaited inaugural crewed mission of Boeing’s Starliner spacecraft has been pushed back again.
Starliner’s first flight with astronauts was expected as early as May 21 after two earlier delays this month, but mission teams need more time to “go through spacecraft closeout processes and flight rationale” and are now aiming to arrive no earlier than 15.09 hours to launch. ET on May 25, according to a NASA release.
The update comes just days after Starliner teams reported a small helium leak in the spacecraft’s service module. They traced the leak to a thruster flange of a single reaction control system, where helium is used to fire the thrusters. Additional time before launch gives specialists more time to evaluate this problem, although tests so far have shown that the leak does not pose a threat to the mission, according to NASA’s latest update.
“Pressure tests conducted on May 15 on the spacecraft’s helium system showed that the flange leak is stable and would not pose a risk at that level during flight,” the space agency said in its press release. “The tests also showed that the rest of the bow 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.”
The mission, called the Crew Flight Test, could be the last major milestone before NASA deems Boeing’s spacecraft ready for routine operations as part of the federal agency’s Commercial Crew Program.
The historic crewed flight took place about two hours after launch on May 6, when it was scrubbed due to a problem with the valve on the second stage, or upper portion, of the Atlas V rocket that will carry Starliner into space.
The NASA astronauts who would crew the mission for a week-long stay on the International Space Station, Suni Williams and Butch Wilmore, were in preflight quarantine but returned to Houston on May 10 to spend time with their families, said Boeing. Williams and Wilmore will fly back to NASA’s Kennedy Space Center in Florida closer to the new launch date, according to the space agency’s latest release.
The Crew Flight Test is a decade in the making – the culmination of Boeing’s efforts to develop a spacecraft worthy of transporting astronauts to and from the International Space Station under NASA’s commercial program.
The launch would mark only the sixth maiden voyage of a manned spacecraft in U.S. history, NASA Administrator Bill Nelson noted at a news conference earlier this month.
“It started with Mercury, then Gemini, then Apollo, the space shuttle, then (SpaceX’s) Dragon – and now Starliner,” he said.
Boeing designed the Starliner to rival SpaceX’s prolific Crew Dragon capsule and expand America’s capabilities for transporting astronauts to the space station.
On board, Williams will also make history as the first woman to embark on such a mission.
Development issues, test flight problems and other costly setbacks have delayed Starliner’s path to the launch pad. Meanwhile, Boeing’s rival under NASA’s commercial crew program – SpaceX – has become the transportation provider for the space agency’s astronauts.
Williams and Wilmore were already in their seats aboard the Starliner capsule on May 6 when engineers discovered a problem and halted the launch.
The United Launch Alliance team, which is building the Atlas V rocket, identified a pressure control valve on a liquid oxygen tank that needed to be replaced. The valve has since been replaced, but the latest problem concerns the helium leak on the Boeing spacecraft that sits on top of the rocket has caused further delay.
If the spacecraft is launched as planned next week, the spacecraft and the astronauts inside will detach from the Atlas V rocket after reaching orbit as Starliner begins firing its own engines. The vehicle will likely take more than 24 hours to reach the space station.
Williams and Wilmore will spend about a week in the orbiting laboratory, where they will join the seven astronauts and cosmonauts already on board, while the Starliner remains docked outside.
The history-making crew will then return home aboard the same Starliner capsule, which is expected to parachute into one of several designated locations in the southwestern United States.
CNN’s Jackie Wattles and Ashley Strickland contributed to this report.