On Thursday, Boeing will have a second chance at a do-over for the space taxi it has built for NASA.
The Starliner capsule will take astronauts to and from the International Space Station, but first it has to complete a test flight without astronauts to verify that its systems all work properly. Its two previous attempts to carry out that preparatory journey — the first in December 2019 and the second in August 2021 — were both marred by serious technical problems. The setbacks have also cost Boeing hundreds of millions of dollars.
But now, finally, Starliner is again at the launching pad. Here’s what you need to know about its flight.
How and when can I watch the Starliner launch?
Liftoff is scheduled for 6:54 p.m. Eastern time on Thursday from Cape Canaveral Space Force Station in Florida. NASA Television will start streaming coverage of the launch at 6 p.m.
Weather forecasters give an 80 percent chance of conditions favorable for launch. There is a backup launch window on Friday at 6:32 p.m., but the weather might be less promising, at only 30 percent, because of expected thunderstorms in the area.
Why has Starliner had so much trouble?
Boeing conducted an uncrewed test flight of Starliner in December 2019. The problems started almost as soon as it reached orbit.
A software error caused the Starliner’s clock to be set to the wrong time. That caused the onboard computer to try to move the spacecraft to where it thought the vessel should be. The firing of the thrusters used up much of the propellant, and plans for Starliner to dock at the space station were called off.
While troubleshooting that problem, Boeing engineers discovered a second flaw that would have caused the wrong thrusters to fire as the capsule prepared for re-entry, potentially leading to the destruction of the spacecraft. They fixed that software flaw while Starliner orbited the Earth, and the capsule landed safely at White Sands, N.M.
Those problems put a hold on what would have been the next step: a demonstration flight with astronauts aboard. NASA told Boeing that it needed to repeat the uncrewed test flight, at Boeing’s cost.
Boeing spent more than a year revamping and retesting the software, and in August last year, Starliner was back at the launching pad at Cape Canaveral Space Force Station in Florida, on top of a second Atlas 5 rocket.
The countdown started, but had to be halted. Flight managers discovered that 13 valves in Starliner’s propulsion system had failed to open.
Boeing then spent about eight months investigating the corrosion that had caused the valves to stick shut. Boeing swapped out the service module — the piece of Starliner below the capsule that houses the propulsion system — with one that had been planned for the next mission.
Now, it’s ready for that second do-over.
Is Starliner carrying cargo on this mission?
Although this mission is not carrying any astronauts, one of Starliner’s seats will be filled by a mannequin named Rosie the Rocketeer. Rosie also flew on the first orbital test in 2019, outfitted with sensors to measure conditions within the capsule.
There is also more than 800 pounds of cargo aboard, mostly food and supplies for the space station crew, but also some memorabilia. The spacecraft is to bring back to Earth almost 600 pounds of cargo from the space station.
Are all of the problems fixed now?
NASA and Boeing officials say they have methodically analyzed and fixed the software flaws that cut short the 2019 test flight. A problem with the communications system has also been fixed.
They also say they understand how the valves became stuck. Moisture in the air reacted with the thruster propellant, nitrogen tetroxide, producing nitric acid that corroded the valves.
“The trick for this flight was to eliminate that moisture and make sure that it doesn’t cause those nitrates to form,” Mark Nappi, vice president and program manager at Boeing for the commercial crew program, said during a news conference on Tuesday. “We went to great extent to make sure that the valve is properly sealed off so there’s no potential for moisture intrusion into the valve.”
Dry nitrogen was sent through the valves to help remove moisture.
During preparations, the valves were opened and closed a number of times without any problems, Mr. Nappi said.
Boeing is also considering longer-term solutions including a redesign of the valves, he said.
Does NASA really need Starliner?
After the space shuttles were retired, the United States had to rely on Russia’s Soyuz rockets for trips to and from the International Space Station. NASA then hired two companies to take astronauts to and from the station: SpaceX and Boeing. At the time of Boeing’s test flight in 2019, it seemed that Starliner would beat out SpaceX’s Crew Dragon capsule for the first mission with astronauts.
But with problems grounding Starliner, SpaceX has since launched seven Crew Dragon missions with astronauts. Five were for NASA. Two others carried private citizens to orbit.
SpaceX’s missions also appear to be significantly less expensive than Boeing’s. When NASA announced the contracts in 2014, Boeing was set to receive $4.2 billion while SpaceX was to receive $2.6 billion. (The space agency did not release details of the contracts, making it difficult to exactly compare the cost of a seat on Starliner with one on Crew Dragon. In 2019, the NASA inspector general estimated that each seat on a Crew Dragon costs $55 million, while a seat on Starliner costs $90 million.)