Mission Control: Challenger, go at throttle up.
Smith: Roger, go at throttle up.
Mission Control: We’re at a minute 15 seconds, velocity 2,900 feet per second (1,977 mph) altitude 9 nautical miles (10.35 statute miles), range distance 7 nautical miles (8.05 statute miles)
Mission Control: Flight controllers are looking very carefully at the situation. Obviously a major malfunction. We have no downlink (communications).