WEBVTT

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BRUCE BUCKINGHAM: Good morning from the Kennedy Space Center in Florida. This is Space Shuttle Discovery's Launch Control.

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The countdown for the launch of Discovery on mission STS-(121) is continuing on schedule this morning.

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Launch is scheduled to occur at about 2:38 p.m. Eastern time, and our launch opportunity window extends for about five minutes.

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This is our third launch attempt in four days. The first two attempts were scrubbed due to lightning and thick clouds.

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Much better chances of being able to launch today than we had last Saturday and Sunday on our first two attempts.

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Again, everything continues to run on schedule as we count down toward our targeted liftoff time at about 2:38 p.m.

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There is one technical issue that the launch team is currently looking at. This is something that just arose over the past few minutes,

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and it appears to be a situation with the circuit breakers that control all the heaters on the shuttle's booster joints.

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Apparently, we lost our backup capability and we would like to have full redundancy for that capability.

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The system is functional at this time and we could fly as is. However, to maintain a full redundancy,

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we're looking at sending a team out to the launch pad, to the mobile launcher platform where this

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circuit breaker panel is, and replacing that circuit breaker.

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So we'll be pulling a team together shortly and preparing them and prepping them on what exactly needs to be done to replace this

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100-amp circuit breaker that controls and commands all of our primary heaters on our,

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on both of our solid rocket boosters, the segment joints on both of the boosters.

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So that will be something that we will be tracking over the next little while as the team is pulled together.

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This is something that has been practiced and planned for. The, the so-called "red" crew that we will be sending out will be minimal,

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just two, perhaps three individuals that go out and do this work. They go out, get access to that specific panel in

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the mobile launcher platform, replace that circuit breaker and then immediately leave the area.

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Other than that, everything's going quite well this morning. The tanking operations to load the external tank with over 500,000 gallons

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of liquid propellants that are used by the shuttle's three main engines lasted about three hours, finishing up at about 7:28 this morning.

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With two hours, four minutes remaining in our scheduled built-in hold, at T-3 hours and holding, this is Shuttle Launch Control.

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