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The latest attempt at an inaugural crewed launch of Boeing’s Starliner spacecraft is on schedule for Wednesday after a computer glitch halted the countdown just before Saturday’s launch.
The historic mission, called the Crew Flight Test, will launch at 10:52 a.m. ET from the Cape Canaveral Space Force Station in Florida. The event will be streamed live on NASA’s website, with coverage beginning at 6:45 a.m. ET.
Veteran NASA astronauts Butch Wilmore and Suni Williams will be the first crew to ride aboard Starliner, propelled into orbit atop an Atlas V rocket built by United Launch Alliance, a joint venture between Boeing and Lockheed Martin .
The long-awaited flight took place 3 minutes and 50 seconds after launch on Saturday afternoon, when an automatic stop was activated by the ground launch sequencer, or computer that launches the rocket. Teams safely extracted the astronauts from the capsule, and Williams and Wilmore returned to the crew quarters as the rocket ran out of fuel.
Joe Raedle/Getty Images
Boeing’s Starliner spacecraft sits atop a United Launch Alliance Atlas V rocket at the Cape Canaveral Space Force Station in Florida on May 31.
Technicians and engineers from United Launch Alliance this weekend assessed ground support equipment and examined three large computers housed in a shelter at the base of the launch pad. Each computer is the same and provides triple redundancy to ensure the safe launch of manned missions.
“Imagine a large rack that is a large computer, where the functions of the computer as a controller are separated into individual cards or circuit boards,” said Tory Bruno, president and CEO of United Launch Alliance, during a press conference on Saturday. . “They all stand alone, but together they form an integrated controller.”
The cards in the computers are responsible for several key systems that must occur before a launch, such as loosening bolts at the base of the rocket so that it can take off after ignition.
During the last four minutes before launch, all three computers must communicate with each other and reach an agreement. But during the countdown on Saturday, a card on one of the computers responded six seconds slower than the other two computers, indicating something was wrong and causing an automatic lockout, according to Bruno.
Over the weekend, engineers evaluated the computers, their power supply and the network communications between the computers. The team isolated the problem to a single ground power supply within one of the computers, which provides power to the computer boards responsible for key countdown events – including the replenishment valves for the rocket’s upper stage, according to an update shared by NASA.
Starliner teams reported no signs of physical damage to the computer, which they removed and replaced with a spare computer. In the meantime, mission specialists continue to analyze the failed propulsion unit to better understand what went wrong.
The other computers and their maps were also assessed and according to the ULA team, they are all functioning normally as expected.
The Starliner mission management team has reviewed computer replacement troubleshooting steps and they have agreed that Starliner will launch on Wednesday, according to an update from NASA.
“I greatly appreciate all the work of the NASA, Boeing and ULA teams over the past week,” Steve Stich, manager of NASA’s Commercial Crew Program, said in a statement. “In particular, the ULA team has worked very hard to quickly learn more about these issues, keep our NASA and Boeing teams informed, and protected for this next effort. We will continue to take it step by step.”
Mission teams had successfully resolved a number of other issues that arose earlier during the countdown to Saturday’s launch attempt. These issues include the loss of data from ground valves responsible for replenishing the liquid oxygen and hydrogen to the second or upper stage of the Atlas V rocket before liftoff.
Both liquid oxygen and hydrogen, used to fuel the rocket, boil off while the rocket sits on the pad before launch, so replenishment continues until liftoff. After evaluating the problem, the mission teams switched to a redundant system for the valve data and were able to resume the process.
Weather conditions are 90% favorable for a Wednesday morning launch, with the only concern being cumulus clouds, the U.S. Space Force’s 45th Weather Squadron said. If the launch doesn’t happen on Wednesday, there will be another possibility for Thursday at 10:29 a.m. ET, according to NASA.
If Starliner lifts off successfully, the astronauts will travel to the International Space Station in just over 24 hours.
Joe Skipper/Reuters
Veteran NASA astronauts Butch Wilmore (left) and Suni Williams are seen Saturday ahead of Starliner’s second launch attempt.
After docking, Williams and Wilmore will spend eight days in the orbiting laboratory, where they will join the seven astronauts and cosmonauts already on board. The two will continue to test the functionality of the Starliner spacecraft while it is docked at the space station then return home aboard the same capsule. It is expected to parachute into one of several designated locations in the southwestern United States.
In the meantime, the two astronauts remain in quarantine to protect their health ahead of launch and practice procedures and simulations ahead of the historic flight, NASA said.