Fresh from repairs to their launch pad in Florida, United Launch Alliance engineers resumed the overnight countdown for their third attempt to send an Atlas V rocket and Boeing’s Starliner spacecraft on a test flight to the International Space Station.
NASA astronauts Butch Wilmore and Suni Williams were scheduled to wake up early Wednesday, don blue pressure suits and head to the launch pad at Cape Canaveral Space Command Station to board a Starliner capsule atop a 172-foot-tall Atlas V rocket.
Go through the door again
Wilmore and Williams have done the same thing twice before, hoping to launch into space on the first crewed flight of Boeing’s Starliner spacecraft. A valve malfunction on the Atlas V rocket thwarted the May 6 launch, after engineers discovered a helium leak in the Starliner spacecraft itself. After weeks of troubleshooting, NASA and Boeing officials decided to try the launch again on Saturday.
All seemed to be going smoothly on Boeing’s long-delayed manned test flight until a computer glitch caused the countdown to automatically halt with just under four minutes to go. Engineers at United Launch Alliance (ULA), the company that makes and operates the Atlas V rocket, discovered that the problem was caused by a fault in a power distribution system connected to a ground computer that controls the final stages of the countdown.
Wednesday’s immediate launch is scheduled for 10:52 a.m. EDT (14:52 p.m. UTC), the time the Cape Canaveral launch site passes under the space station’s orbital plane. Forecasters predict a 90 percent chance of favorable weather at launch. You can watch NASA’s live coverage in the video embedded below.
The countdown began late Tuesday night with the firing up of an Atlas V rocket, which was scheduled to be filled with cryogenic liquid hydrogen and liquid oxygen propellants around 5 a.m. EDT (9 a.m. UTC). Kerosene fuel was loaded onto the Atlas V’s first stage booster ahead of the mission’s first launch in early May.
The two Starliner astronauts left crew quarters at NASA’s Kennedy Space Center for the 20-minute drive to the launch pad, arriving shortly before 8 a.m. EDT (12 noon UTC) and taking their seats inside the Starliner capsule. Following pressure checks of the astronauts’ spacesuits and the Starliner crew cabin, ground teams are scheduled to evacuate the pad about an hour before liftoff.
If all systems are ready for launch, the Atlas V will ignite its Russian-made RD-180 main engine and two solid-fuel boosters and lift off from Cape Canaveral, heading northeast over the Atlantic Ocean. Not only will Wilmore and Williams be the first to fly into space on Boeing’s Starliner, they will also be the first astronauts aboard the Atlas V rocket, which has made 99 flights to date carrying satellites for the U.S. military, NASA and commercial customers.
The rocket’s Centaur upper stage will deploy Starliner into space about 15 minutes after liftoff. Critical ignition by Starliner’s engines will occur about 31 minutes into the flight, completing the insertion process into low Earth orbit and preparing the spacecraft for an automatic docking with the International Space Station at 12:15 p.m. EDT (4:15 p.m. UTC) on Thursday.
The two-person crew will stay aboard the space station for at least a week, but an extension is expected if the mission goes well. Officials may decide to extend the mission to complete more tests or to wait for optimal weather at Starliner’s primary and backup landing sites in New Mexico and Arizona. Once the weather is favorable, Starliner will detach from the space station and parachute to land.
Crew test flights are a prerequisite for Boeing’s crewed capsule to become operational with NASA, which awarded Boeing and SpaceX multi-billion dollar commercial crew contracts in 2014. SpaceX’s Crew Dragon began flying astronauts in 2020, but Boeing’s project has been hit by years of delays.
Wilmore and Williams, former U.S. Navy test pilots, will take over manual control of Starliner at several points during the test flight as they evaluate the spacecraft’s flying characteristics and facilities for future flights that could carry four astronauts at a time instead of two.
“The media should not expect perfection,” Wilmore told Ars earlier this year. “This is a test flight. Flying and operating in space is hard. Really hard. And we’ll find something, and that’s to be expected. This is the first flight that brings together all of the capabilities of this spacecraft.”
