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After a decade of planning, Boeing’s Starliner is set to begin its first crewed flight on Saturday.
The new spacecraft is scheduled to launch on an Atlas V rocket at 12:25 pm ET from Cape Canaveral Space Command Station in Florida. Live streaming of the event will begin at 8:15 am ET on NASA’s website.
Mark Berger, launch weather officer for the 45th Weather Squadron at Cape Canaveral Space Station, said conditions were 90 percent favorable for the launch, with wind and cumulus clouds being the only concerns.
The mission, called “Crew Flight Test,” is the culmination of Boeing’s efforts to develop a spacecraft comparable to SpaceX’s Crew Dragon spacecraft and expand U.S. options for transporting astronauts to the space station under NASA’s Commercial Crew Program. The federal agency’s efforts are intended to foster collaboration with private industry partners.
If successful, the flight will mark only the sixth manned spacecraft to fly in space in U.S. history, NASA Administrator Bill Nelson said at a press conference in May. The craft will be crewed by veteran NASA astronauts Butch Wilmore and Suni Williams.
“It started with Mercury, then Gemini, Apollo, Space Shuttle, then (SpaceX’s) Dragon and now Starliner,” Nelson said.
Williams will make history as the first woman to take part in such a mission.
Once in orbit, the Starliner spacecraft carrying Wilmore and Williams will separate from the Atlas V rocket and ignite its own engines. The Starliner will travel more than 24 hours to the International Space Station, where it is scheduled to dock at 1:50 p.m. ET on Sunday.
The astronauts will test various functional aspects of the Starliner, including the performance of the spacecraft’s thrusters, how the spacesuits function inside 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 two astronauts will join seven astronauts and cosmonauts already aboard the space station and will spend eight days aboard the orbital laboratory.
According to Steve Stich, manager of NASA’s commercial crew program, who spoke at a press conference Friday, the astronauts will be testing Starliner’s “safe haven” feature, designed to provide an escape route for the space station’s crew if there’s a problem on the space station.
On the return journey, Williams and Wilmore will return in the same Starliner capsule, which is scheduled to land at a location in the southwestern United States.
The earliest Williams and Wilmore can return is June 10, but other dates are possible if the weather is bad, Stich said.
NASA said that if the spacecraft doesn’t launch as scheduled on Saturday, there are backup opportunities to launch on June 2, June 5 and June 6.
Years of stalled development, test-flight problems and other costly obstacles have slowed Starliner’s path to launch. Meanwhile, Boeing’s rival in NASA’s commercial program, SpaceX, has become the agency’s main provider of astronaut transport.
The mission could be the last major milestone before NASA determines Boeing’s Starliner spacecraft is ready for routine operations ferrying astronauts and cargo to the space station.
“We look forward to flying this mission. It’s a test flight and we’re going to learn a lot,” Mark Nappi, vice president and program manager for Boeing’s Commercial Crew Programs, said in a statement. “We’ll continue to improve, and that improvement will begin with the Starliner 1 mission and will be even better in missions we fly in the future.”
Just two hours before Starliner was due to attempt its first crewed launch on May 6, engineers discovered a problem with the second stage, or upper valve, of its Atlas V rocket. The entire stack, including the rocket and spacecraft, was rolled back from the pad for testing and repairs.
The mission team then reported a small helium leak inside the spacecraft’s service module, which was traced to a part called a flange on the Single Reaction Control System thruster, which uses helium to power the thrusters.
The space agency said the leak poses no threat to the mission.
“We seriously looked at what our options were with this particular flange,” he said. “The fuel lines, the oxidizer lines, the helium lines all go into the flange, making it difficult to work on. It’s almost unsafe to work on.”
Rather than building a replacement to fix the leak, the team determined the helium leak was small enough to be manageable, Stich said.
“When we looked at this issue, it wasn’t a question of trade-offs,” Nappi said. “The question was, ‘Is it safe or isn’t it?’ And it is safe, and that’s why we decided we could fly with what we have.”
The mission team monitored for leaks during Saturday morning’s launch countdown but has not reported any issues so far. The team has spent the past two weeks evaluating acceptable levels of helium leakage and troubleshooting outlined in a rulebook used by engineers, Nappi said.
As engineers evaluated the helium issue in the run-up to launch day, they also found a “design vulnerability” in the propulsion system — identifying a distant-future scenario in which a particular thruster could fail if the spacecraft left Earth orbit, with no backup means of returning safely home.
NASA and Boeing have since worked with the thruster vendor to develop a backup plan for performing a deorbit burn in case such a situation were to occur, Stich said during a May 24 press conference.
“We have restored redundancy of backup capabilities in the event of a very rare series of direct burn failures,” Stich said.
Following a flight readiness meeting on May 29, leaders from NASA, Boeing and United Launch Alliance, the company that built the rocket, “reviewed launch readiness, including all systems, facilities and teams to support the test flight,” according to the space agency.
The mission team also took a closer look at Starliner’s parachutes after one of the parachutes didn’t fully inflate during Blue Origin’s recent crewed suborbital flight, which uses components similar to that parachute system, Stich said.
Blue Origin shared flight data with Boeing and NASA, and after evaluating Starliner’s parachutes, the team deemed it “flyable.”
Dana Weigel, NASA’s International Space Station program manager, said the space station experienced an anomaly on Wednesday but that Starliner would be able to help repair it.
The pump in the station’s urine treatment device assembly failed.
“This urine treatment plant takes all of the crew’s urine and treats it in the first stage of the water recovery system,” Weigel said, “and then sends it downstream to the water treatment plant, which turns it into drinking water. The station is actually designed to be a closed loop.”
The pump was expected to function into the fall, and a replacement was scheduled to fly on a cargo resupply mission in August, but the pump failure “resulted in us having to store a lot of urine,” Weigel said.
Currently, urine must be stored on board in containers. To solve this problem, a replacement pump was hastily installed in the Starliner’s cargo. The pump weighs about 150 pounds, so the team unloaded two crew suitcases from the Starliner, containing clothes and toiletries like shampoo and soap carefully selected by Wilmore and Williams.
The space station has a stockpile of general-purpose clothing and toiletries to serve the two astronauts during their short stay, Weigel said.
Wilmore and Williams have been in crew quarantine since late April to protect their health ahead of launch, according to NASA astronaut Mike Fink, who will pilot Boeing’s Starliner 1 mission following the successful test flight.
“Butch and Suni have every confidence in our rocket, our spacecraft and our operations and leadership management teams and we are absolutely ready to go,” he said.
CNN’s Debrina Chakraborty contributed to this report.