heavy" precipitation. The weather conditions violated one launch criteria ("The flight path of the vehicle should not be through mid level clouds 6,000 feet or greater in depth, when the freezing level is in the clouds."), the weather team reported it as an icing issue, not a lightning risk. After discussions about the risk posed by ice, the NASA program directors gave the go-ahead. The Atlas was struck by lightning around 38 seconds into launch. Control of the booster started to fail and it broke apart from structural loads at T+50 seconds. The Range Safety Officer sent the destruct command, but there was no evidence that the booster ever received it. Debris rained out of the clouds onto the pad area, the shoreline, or in shallow water just off of it and was easily recovered. A section of the payload fairing was found to have multiple small holes burned in it due to repeated lightning strikes. The key piece of evidence was Atlas's flight computer, which was recovered intact and examined. It was discovered that the last command issued was a signal to gimbal the booster engines hard to right, caused apparently by lightning induced Electromagnetic pulse (EMP) altering a single word in the guidance program. The launch caused significant reappraisals of weather guidelines at Cape Canaveral. The 45th Weather Squadron uses rules developed after the incident to determine if weather conditions allow a launch. Variants References External links William W. Varnedoe Collection, The University of Alabama in Huntsville Archives and Special Collections NASA photographs, mission planners guides, contracts, and other documents pertaining to the Atlas-Centaur. Rockets and missiles Atlas (rocket family)