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Description of Driving Event:

In the early morning hours before launch, a KSC ice team performed an inspection of the Challenger and pad. Their specific aim was to check for the amount and type of ice. They had with them an infrared gun designed to measure surface temperatures. This instrument was focused on the external tank and Solid Rocket Boosters (SRB's) during the course of the survey. The infrared gun indicated temperatures on the right SRB of from seven to nine degrees Fahrenheit, compared to 23 to 25 degrees for the left SRB. This discrepancy was not reported to launch team officials. Later, tests indicated the infrared gun requires a minimum of 40 minutes to stabilize at the temperatures experienced at KSC on the morning of the launch. The gun was focused on the right SRB prior to the time it had stabilized, indicating the readings taken were not reliable. Ice team members displayed a lack of sensitivity to potentially hazardous conditions to which they were evaluating and, nevertheless, should have reported the low readings.