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Boeing’s Starliner is set to make its first crewed flight on Saturday, a mission a decade in the making.
The new spacecraft is expected to lift off atop an Atlas V rocket at 12:25 p.m. ET from the Cape Canaveral Space Force Station in Florida. A live stream of the event will begin at 8:15 a.m. ET on NASA’s website.
Weather conditions are 90 percent favorable for launch, with wind and cumulus clouds the only concerns, according to Mark Burger, weather officer for the 45th Weather Squadron at Cape Canaveral Space Force Station.
The mission, called Crew Flight Test, is the culmination of Boeing’s efforts to develop a spacecraft to compete with SpaceX’s Crew Dragon capsule and expand the US’s ability to carry astronauts to the space station under NASA’s commercial crew program. The federal agency’s initiative aims to foster collaboration with private industry partners.
If successful, the flight would mark only the sixth inaugural flight of a crewed spacecraft in U.S. history, NASA Administrator Bill Nelson noted at a press conference in May. Veteran NASA astronauts Butch Wilmore and Suni Williams will be on board.
“It started with Mercury, then Gemini, then Apollo, the Space Shuttle, then (SpaceX) Dragon — and now Starliner,” Nelson said.
Williams will also make history as the first woman to fly aboard such a mission.
After reaching orbit, the Starliner crew capsule with Wilmore and Williams separates from the Atlas V rocket and fires its own engines. Starliner is expected to spend more than 24 hours traveling to the International Space Station, with landing expected to occur at 1:50 p.m. ET on Sunday.
The astronauts will test various aspects of the Starliner’s capabilities, including the performance of the spacecraft’s thrusters, the functioning of their spacesuits in the capsule, and manual piloting in case the crew needs to override the spacecraft’s autopilot.
Joe Skipper/Reuters
NASA astronauts Suni Williams (left) and Butch Wilmore pose before launch.
The astronaut duo will join seven astronauts and cosmonauts already aboard the space station and spend eight days in the orbiting laboratory.
The astronauts will test the Starliner’s “safe haven” capability to offer the space station crew shelter in the event of a problem on the space station, according to Steve Stich, NASA’s commercial crew program manager, who spoke during a press conference Friday.
When it’s time to head home, Williams and Wilmore return using the same Starliner capsule and land at a location in the southwestern United States.
The closest possible return for Williams and Wilmore is June 10, but other dates are available in case of bad weather, Stich said.
If the spacecraft doesn’t lift off as scheduled on Saturday, there are backup launch opportunities on June 2, June 5 and June 6, according to NASA.
Years of stalled development, problems with test flights and other costly setbacks slowed the Starliner’s journey to the launch pad. Meanwhile, Boeing’s competitor in NASA’s commercial program — SpaceX — has become a transportation provider for the space agency’s astronauts.
The mission could be the last major milestone before NASA finds the Boeing Starliner spacecraft ready for routine operations delivering astronauts and cargo to the space station.
“We’re looking forward to flying this mission. This is a test flight; we know we’re going to learn things,” Mark Nappi, vice president and program manager of Boeing’s Commercial Crew program, said in a statement. “We’re going to improve, and that improvement starts with the Starliner mission -1 and it will be even better than the mission we are about to fly on.”
The Starliner was only about two hours away from its first crewed launch attempt on May 6 when engineers identified a problem with a valve on the second stage, or upper part, of the Atlas V rocket. The entire stack, including the rocket and spacecraft, rolled back from the launch pad for testing and repair.
Afterwards, mission teams reported a small helium leak in the spacecraft’s service module. The leak was traced to a part called a flange on one nozzle of the reaction control system, where helium is used to allow the nozzles to fire.
The space agency said the leak did not pose a threat to the mission.
“We were really exploring what our options were with this particular flange,” he said. “The fuel line, the oxidizer line, and the helium line all go into the flange, which makes the job difficult. It’s almost dangerous to work on it.’
Instead of performing a replacement to fix the leak, the teams decided the helium leak was small enough to handle, Stich said.
“When we looked at this issue, it didn’t lead to trading,” Nappi said. “It came down to, ‘is it safe or not?’ And it’s safe. And that’s why we decided that we can fly with what we have.’
During the countdown to launch, mission teams will monitor the leak to see if it increases. Teams have spent the past two weeks assessing acceptable levels for a helium leak and troubleshooting problems that were laid out in the rules engineers will use to assess the leak Saturday morning, Nappi said.
While evaluating the helium problem, engineers also noted a “design vulnerability” in the propulsion system — essentially identifying a remote scenario in which some of the thrusters could fail when the vehicle leaves Earth orbit, with no backup method of safely returning home.
NASA and Boeing have since worked with the thruster supplier to come up with a backup plan to perform a deorbital burn should that situation arise, Stich said at a May 24 news conference.
“We restored that redundancy for backup capability in a very remote fail-safe set for direct burn,” Stich said.
After a flight readiness review meeting on May 29, senior officials from NASA, Boeing and United Launch Alliance, which built the rocket, “verified readiness for launch, including all systems, equipment and teams supporting the test flight,” the space agency said.
The mission teams also took a close look at the Starliner’s parachutes after one parachute failed to fully inflate on Blue Origin’s recent crewed suborbital flight. The Starliner uses components that are similar to the parachute system, Stich said.
Blue Origin shared flight data with Boeing and NASA, and after evaluating the Starliner’s parachutes, the team deemed them “good to fly.”
The space station experienced an anomaly Wednesday that Starliner could help correct, said Dana Weigel, NASA’s International Space Station program manager.
The pump on the station’s urine processor assembly has failed.
“This urine processor takes all of the crew’s urine and processes it in the first step of the water recovery system,” Weigel said. “Then it sends it downstream to a water processor that turns it into potable water. The station is really designed as a closed loop.”
The pump was expected to operate until the fall, and a replacement was scheduled to fly aboard a cargo resupply mission scheduled for August. But the pump failure “put us in a position where we would have to store an awful lot of urine,” Weigel said.
Now the urine must be stored on board in containers. To solve this problem, a spare pump was quickly swapped into the Starliner’s cargo. The pump weighs about 150 pounds, so the team removed two crew suitcases from the Starliner with clothing and toiletries, such as shampoo and soap, handpicked by Wilmore and Williams.
The space station has a standby supply of generic clothing and toiletries that the astronaut duo will use instead for their short stay, Weigel said.
Wilmore and Williams have been in crew quarantine since late April to protect their health before launch, said NASA astronaut Mike Fincke, who is scheduled to serve as pilot for the upcoming Boeing Starliner-1 mission, which will follow the successful test flight.
“Butch and Suni have full confidence in our rocket, our spacecraft and our operations and management teams, and they’re definitely ready to go,” he said.
CNN’s Deblina Chakraborty contributed to this report.