Image above: Space Shuttle Atlantis awaits Saturday's liftoff after a scrubbed launch attempt on Friday. Photo credit: NASA

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Atlantis' launch scrubbed due to ECO sensor problem

The launch of Space Shuttle Atlantis has been scrubbed until Saturday due to a problem with one of the vehicle's external tank ECO sensors.

NASA managers will hold a press conference no earlier than 12:30 p.m. EDT to discuss the sensor issue and tomorrow's liftoff attempt. The press conference will be carried live on NASA TV.

The new launch time for Atlantis is targeted for 11:15 a.m. on Saturday.

The ECO sensor issue arose earlier in today's countdown when launch controllers detected a problem with one of the four ECO sensors inside the hydrogen section of the space shuttle's orange external tank. The sensors monitor hydrogen levels inside of the tank and trigger the orbiter's engines to shutdown when gas levels drop below a specified level.

During a Thursday evening news conference Wayne Hale, Space Shuttle Program manager, said the decision to fly came about after a lively and inclusive meeting with space shuttle mission managers and engineers held in the early afternoon. "If you ever wanted to see the difference between the old NASA and the new NASA, you should've been over there today. There was a chance for everyone to participate." Hale continued to say that the Mission Management team's vote to fly on Friday was nearly unanimous.

The decision to launch follows analysis of an issue found with one of Atlantis' three electricity-generating fuel cells, which was discovered during pre-launch preparations earlier this week. NASA engineers have determined that any failure of the suspect fuel cell during the mission poses no danger to Atlantis and its crew. They also believe two fuel cells alone would provide Atlantis with enough power to accomplish the major goals of the mission.

During their three spacewalks, crew members of Atlantis will install the P3/P4 integrated truss and a second set of solar arrays on the space station, doubling the station’s current ability to generate power from sunlight and adding 17.5 tons to its mass.

Learn more about the truss

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