Extended Abstract (76K)6.3
Lightning Protection at the Kennedy Space Center and Cape Canaveral Air Force Station
Pedro J. Medelius, Dynacs, Inc., Kennedy Space Center, FL; and W. P. Roeder and J. Willingham
Frequent lightning activity in Florida has resulted in the need for effective lightning protection systems at the Kennedy Space Center (KSC) and at Cape Canaveral Air Force Station (CCAFS). Critical flight hardware, such as the Space Shuttle vehicle launched from KSC and the expendable launch vehicles (ELV’s) launched from CCAFS, must be protected against direct lightning strikes, including their indirect effects, and the effects of nearby strikes. Electronic equipment is susceptible to damage when exposed to voltage beyond safe limits. Lightning strikes, which usually carry currents on the order of several thousand amperes, generate large magnetic fields with fast rise and decay times. These fast varying electric and magnetic fields result in induced voltages and currents on any conductor, which, if attached to an electronic device, can cause immediate failure of the device, or cause lesser damage which can significantly reduce its lifetime. An even more dangerous situation could result from a direct lightning attachment to an explosive or flammable device in a space vehicle or a storage facility.
Statistical and probability studies of lightning strike and damage data performed at KSC/CCAFS over the years has resulted in a comprehensive set of lightning protection systems and methods. For instance, different techniques have been applied to KSC’s launch pad structures to estimate the lightning protection effectiveness for the gaseous oxygen vent arm. In-depth studies of indirect effects caused by nearby lightning strikes have also affected the lightning protection criteria.
Lightning protection at the Space Shuttle launch pads is provided primarily by a 70-foot insulating fiberglass mast 5 feet in diameter located on the Fixed Service Structure with a lightning rod at the top of the mast. A catenary wire running from the top of the mast to grounding points 1000 feet to the north and south of the tower is used to direct the current away from the pad structure. The lightning protection mast is struck an average of three times per year. Nevertheless, there have been instances when a lightning flash has traveled past the catenary wire protection and has directly struck the launch pad structure.
Overhead protective grids, grounded at multiple points, are widely used at CCAFS and at selected installations at KSC. These grids are intended to divert the lightning current to ground and to prevent it from causing damage to sensitive equipment or personnel working underneath. Other launch pads at KSC/CCAFS use different lightning protection designs.
This paper presents a compilation of the lightning protection systems in use at KSC and CCAFS, as well as a description of the systems used to monitor the lightning activity and its direct and indirect effects.
Session 6, Space Vehicle Operations Support (Parallel with Joint Session J1)
Tuesday, 14 May 2002, 2:00 PM-5:15 PM
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