scope:

Description of Driving Event:

Launch complex 39B demonstrated satisfactory capability during the STS 51-L launch, with a few exceptions. It was anticipated that the initial shuttle launch from LC 39B would uncover minor problems, and some discrepancies between the Pad A and Pad B systems. Damaged or loosened items due to the launch have been identified as candidates for additional pad "hardening" and other mechanical/electrical systems had minor operating differences than those on LC 39A. A freeze plan was first used during STS 51-L, which allowed vehicle operations to safely continue at below freezing temperatures. The freeze plan was successful in that vehicle operations continued but the resulting build-up in ice is not considered desirable for future operations. A water systems protection plan, to eliminate the necessity of continuously running water through pipes in very cold weather to prevent freezing inside, is being studied. If operations below freezing temperatures are essential, water system modifications will be required.