NASA Studying Engine Computer Glitch on Space Shuttle Discovery

Shuttle Discovery's Gas Leaks Repaired In Time for Wednesday Launch
The space shuttle Discovery and its STS-133 crew will deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the International Space Station. The launch attempt on Wed., Nov. 3 was delayed, however. (Image credit: NASA/Troy Cryder)

CAPE CANAVERAL, Fla. ? NASA engineers are studying anapparent engine controller glitch in a backup system on the space shuttleDiscovery, in the hopes of solving the issue in time for the shuttle's scheduled launch tomorrow.

The glitch is affecting the backup computer controller on Discovery'sMain Engine No. 3, but further details have not yet been released. During the shuttle's main engine checkouts, the backup controller for engine 3 did not turn on as expected, NASA officials said in a statement. Engineering teams are continuing to investigate the issue.

Earlier today (Nov. 2), shuttle engineers noticed a separate problemwith the same backup computer system, but the issues were said to have beenresolved. [GRAPHIC:NASA's Space Shuttle ? From Top to Bottom]

"After addressing a couple issues last night, ourcountdown work is currently back on schedule," NASA test director StevePayne told reporters during a mission status briefing this morning.

Discoveryis slated to blast off tomorrow (Nov. 3) at 3:52 p.m. EDT (1952 GMT) from a seasidepad here at NASA's Kennedy Space Center. The mission has been delayed by twodays by other technical issues that have since been solved.

The shuttle's STS-133 mission management team is scheduledto meet at 5 p.m. (2100 GMT) to discuss the issue and make a decision onfurther action.

If the issue is resolved, NASA would then proceed with plansto begin fueling Discovery's external tank early tomorrow morning for itsafternoon launch into space.

Spaceshuttle Discovery will begin its 39th and final mission to theInternational Space Station when it blasts off this week. Weather forecasts continueto show a 70 percent chance of acceptable conditions for launch tomorrow.

On its 11-day mission, Discovery will haul critical spareparts to the space station, including a storage room and a humanoidrobot to assist the crew of the orbiting laboratory.

Discovery was originally scheduled to launch Nov. 1. The space agency delayed the launch by one day after detecting helium and nitrogen leaks on the shuttle. Another day of delay, to allow time to complete repairs, pushedthe launch to Nov. 3.

While the weather outlook forWednesday looks promising, NASA is tracking some other storms that could stallDiscovery's flight if it suffers another launch delay.

A weather front pushing down intoparts of central Florida could cause concerns if Discovery's launch is stalledanother 24 hours or more, according to Kathy Winters, NASA's shuttle weatherofficer.

NASA has until Sunday, Nov. 7 to launch Discovery within thecurrent window. After that, the space agency would have to wait until earlyDecember to try again.

Follow Staff Writer Denise Chow onTwitter @denisechow asshe covers Discovery's final space voyage from Cape Canaveral, Fla. Click here formission updates, new stories and a link to NASA's live webcast coverage.


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Denise Chow
NBC News science writer

Denise Chow is a former staff writer who then worked as assistant managing editor at Live Science before moving to NBC News as a science reporter, where she focuses on general science and climate change. She spent two years with, writing about rocket launches and covering NASA's final three space shuttle missions, before joining the Live Science team in 2013. A Canadian transplant, Denise has a bachelor's degree from the University of Toronto, and a master's degree in journalism from New York University. At NBC News, Denise covers general science and climate change.