MER-B launch recycle | MER-B launch video (Real Media)
Mars Exploration Rover B (MER-B) launch attempt at the 1st window of 10:35:23 p.m. EST was halted at T-minus 7 seconds due to an indication that the fill and drain valve on the 1st stage did not close properly. The launch team reset the countdown clock and started a procedure to recycled the valve three times. The valve behaved properly. Delta II/MER-B launched on time during the 2nd launch window on 7/7/03 at 11:18:15.170 p.m. EST.
The launch attempt on Sunday, July 6. scheduled for 10:43:16 p.m. EST was delayed to provide time to replace a battery on the flight safety system. The launch originally scheduled for Saturday, June 28 at 11:57 p.m. EST was scrubbed due to upper atmosphere winds. Upon inspection after the launch attempt, the mission management team decided to delay the launch to repair a 1/4" thick band of cork insulation on the 1st stage.