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The latest attempt at a crewed maiden launch of Boeing’s Starliner spacecraft is on track for Wednesday after a computer glitch interrupted the countdown moments before liftoff Saturday.
The historic mission, called Crew Flight Test, is scheduled to launch at 10:52 a.m. ET from the Cape Canaveral space station in Florida. The event will be streamed live on the NASA website, with coverage beginning at 6:45 a.m. ET.
Veteran NASA astronauts Butch Wilmore and Suni Williams will be the first crew to board the Starliner, propelled into orbit atop an Atlas V rocket built by United Launch Alliance, a joint venture between Boeing and Lockheed Martin.
The highly anticipated flight was 3 minutes and 50 seconds from liftoff Saturday afternoon, when an automatic shutdown was triggered by the ground launch sequencer, or the computer that launches the rocket. The teams safely extracted the astronauts from the capsule, and Williams and Wilmore returned to the crew quarters as the fuel was drained from the rocket.
United Launch Alliance technicians and engineers evaluated ground support equipment over the weekend, examining three large computers housed in a shelter at the base of the launch pad. Each computer is identical, providing triple redundancy to ensure the safe launch of crewed missions.
“Imagine a large rack that is a large computer in which the functions of the computer as a controller are divided separately into individual boards or circuit boards,” said Tory Bruno, president and CEO of United Launch Alliance, during a press conference on Saturday. . “They are all self-contained, but together they form an integrated controller. »
The boards inside the computers are responsible for different key systems that must be activated before a launch, such as loosening bolts at the base of the rocket so it can take off after ignition.
During the last four minutes before launch, the three computers must communicate and hear each other. But during Saturday’s countdown, a card on one of the computers responded six seconds slower than the other two computers, indicating something was wrong and triggering an automatic hold, according to Bruno.
Over the weekend, engineers evaluated the computers, their power supply, and network communications between the computers. The team isolated the problem to a single ground power supply in one of the computers, which powers computer boards responsible for key countdown events, including the rocket’s upper stage resupply valves. , according to an update shared by NASA.
Starliner crews reported no signs of physical damage to the computer, which they removed and replaced with a spare. Meanwhile, mission specialists continue to analyze the faulty powerplant to better understand what went wrong.
The other computers and their cards were also evaluated, and all are functioning normally as expected, according to the ULA team.
The next attempt
Mission teams successfully resolved a few other issues that surfaced earlier in the countdown to Saturday’s launch attempt. Those problems included a loss of data from ground valves responsible for resupplying liquid oxygen and hydrogen to the second stage, or upper stage, of the Atlas V rocket before liftoff.
Liquid oxygen and hydrogen, used to power the rocket, evaporate as the rocket sits on the platform before launch, so resupply continues until liftoff. After assessing the problem, mission teams switched to a redundant system for valve data and were able to resume the process.
Weather conditions are 90% favorable for a launch Wednesday morning, with the only concern being cumulus clouds, according to the 45th Weather Squadron of the US Space Force. If the launch does not happen on Wednesday, there is another opportunity on Thursday at 10:29 a.m. ET, according to NASA.
If Starliner launches successfully, astronauts will spend just over 24 hours traveling to the International Space Station.
After docking, Williams and Wilmore are expected to spend eight days in the orbiting laboratory, joining the seven astronauts and cosmonauts already on board. The two men will continue to test the functionality of the Starliner spacecraft while it is docked with the space station, then return home aboard the same capsule. He is expected to parachute to a landing in one of several designated locations in the southwestern United States.
In the meantime, both astronauts remain in quarantine to protect their health before launch, and they practice procedures and simulations before the historic flight, according to NASA.
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