INVESTIGATION OF THE TRIGGERING OF LIGHTING BY LAUNCH VEHICLES DURING ASCENT

THE SPECIFIC OBJECTIVE OF THIS PROPOSAL IS TO DEVELOP A TRIGGERED LIGHTNING MODEL WHICH HAS THE ABILITY TO RELIABLY ASCERTAIN THE ELECTRICAL THREAT TO ASCENDING LAUNCH VEHICLES. THIS WILL BE ACCOMPLISHED THROUGH A SERIES OF SPECIFIC TASKS, WHICH EXAMINE ALL IMPORTANT ASPECTS OF THE TRIGGERING PHENOMENON INDIVIDUALLY. TASKS ARE PROPOSED TO INVESTIGATE: (1) THE MICROPHYSICS OF THE DISCHARGE PROCESS; (2) THE EFFECT OF THUNDERSTORM PARTICLES; (3) THE EFFECT OF GLOBAL AND LOCAL VARIATIONS IN AIR PRESSURE; (4) THE EFFECT OF A ROCKET PLUME, AND (5) THE CONDITIONS UNDER WHICH ARC FORMATION OCCURS RATHER THAN SIMPLE ELECTRICAL CORONA. THE RESULTS OF THE SPECIFIC TASKS WILL BE INTEGRATED INTO A SINGLE TRIGGERED LIGHTNING MODEL. THIS MODEL, GIVEN THE FLIGHT ENVIRONMENT, WILL BE ABLE TO PREDICT WHETHER TRIGGERED LIGHTNING CAN OCCUR FOR A SPECIFIC LAUNCH VEHICLE,AND WILL ALSO BE ABLE TO PREDICT THE EFFECT ON THE VEHICLE IF TRIGGERED LIGHTNING DOES OCCUR.