KSC ABFM 2000–A field program to facilitate safe relaxation of the lightning launch Commit criteria for America's space program

Launches of both expendable and reusable vehicles, including the Space Shuttle, are constrained by weather launch commit criteria (LCC). The most conservative of these LCC are those designed to avoid the occurrence of triggered lightning such as that which destroyed Atlas-Centaur 67 in 1987. The conservatism in these rules is required to assure safety in the absence of a more complete theoretical and observational understanding of charge production, transport and dissipation in the atmosphere.

KSC ABFM 2000 is a field program designed to test at least one proposed model for charge dissipation in anvil clouds and to improve the use of remote sensing measurements to determine the triggered lightning threat. The goal is to revise several LCC related to anvil and thick layered clouds to simultaneously make them safer and less restrictive.

The program will use the University of North Dakota Citation II instrumented with both airborne electric field mills (ABFM) and cloud physics instrumentation to explore the connection between electrical and microphysical properties of target clouds. At the same time, radar observations at several wavelengths, some with Doppler and dual polarization, will be made from the ground. Passive microwave measurements, a surface electric field mill network and a suite of lightning detection sensors will complete the ground-based instrumentation.

This paper presents an overview of the observation program and the methodology to be applied to revise the lightning LCC based on these observations.