During space shuttle main engine checkouts today, the backup controller for engine 3 did not turn on as expected. There appeared to be an issue with one of three power phases, which was narrowed down to either a cockpit circuit breaker or switch that provides power. The circuit breaker and switch were turned off and on, restoring power, according to NASA.
The space agency said engineers continue to analyze data that showed voltage irregularities and will meet this afternoon to review their data.
Earlier today, around 10 a.m., countdown activities continued to pick up as space shuttle Discovery is a day away from its final launch. Technicians are inspecting the external tank liquid oxygen feed line. The onboard and ground communications systems will be activated this afternoon and preparations are being made to move the rotating service structure away from the shuttle this evening.
“There is excitement in the air,” said NASA Test Director Steve Payne. “People are putting their game faces on.”
This mission is the last spaceflight for Discovery, NASA’s oldest active shuttle. Its history includes deployment of NASA’s Hubble Space Telescope and two successful Return to Flight missions, STS-26 and STS-114.
“When she goes, she’s going to take a little bit of everyone of us and we’re ready,” Payne said.
The weather forecast is holding steady with a 70 percent chance of acceptable conditions at launch time Wednesday. Liftoff is scheduled for 3:52 p.m. EDT.
Meanwhile, Boeing said its engineers and technicians are supporting Discovery’s final mission, in part by processing the shuttle’s payload, which includes the last U.S. pressurized element to be delivered to the International Space Station (ISS).