Workers carry away the faulty Enhanced Main Events Controller from Shuttle Endeavour at Launch Pad 39A.

Workers carry away the faulty Enhanced Main Events Controller (E-MEC) from Shuttle Endeavour at Launch Pad 39A. The E-MEC became suspect during the Jan. 31 launch countdown and mission STS-99 was delayed when NASA managers decided to replace it. Each Shuttle carries two enhanced master events controllers (E-MECs), which provide relays for onboard flight computers to send signals to arm and fire pyrotechnics that separate the solid rockets and external tank during assent. Both E-MECs are needed for the Shuttle to be cleared for flight. Currently Endeavour and Columbia are the only two orbiters with the E-MECs. Built by Rockwell's Satellite Space Electronics Division, Anaheim, Calif., each unit weighs 65 pounds and is approximately 20 inches long, 13 inches wide and 8 inches tall. Previously, three Shuttle flights have been scrubbed or delayed due to faulty MECs: STS-73, STS-49 and STS-41-D. The next scheduled date for launch of STS-99 is Feb. 11 at 12:30 p.m. EST