An Analysis of Lightning Risk and Convective Cloud Cover for Two Proposed Commercial Spaceport Sites

The Aerospace Corporation was contracted by the Volpe National Transportation Systems Center to provide technical support to the Federal Aviation Administration, Office of Commercial Space Transportation (FAA/AST), to assess the risks involved with triggered lightning during suborbital launches and reentries of reusable launch vehicles (RLVs) from the proposed Southwest Regional Spaceport in New Mexico and from the proposed Oklahoma Spaceport, in Burns Flat, Oklahoma.

In support of this effort, we performed a lightning climatology for the period of 1 Jan 1990 – 30 Sept 2004 at two existing sites with locations nearly identical to the above spaceports (Clinton-Sherman Air Force Base and White Sands Missile Range) in order to assess the diurnal and seasonal probability of naturally occurring lightning. We also analyzed the correlations between naturally occurring lightning and convective cloud types for the months of January and July 1999. Three-hourly data from the Cloud Depiction and Forecast System (CDFS2), which incorporates Defense Meteorological Satellite Program (DMSP) cloud sensors, was used. Emphasis was placed on identifying the cloud types most commonly associated with lightning and their thickness. The presence of cloud layers and their separation at the times where lightning was observed were also studied. Using five different concept RLV designs, and their specific characteristics, an attempt to identify triggering conditions and their associated risks during launch/reentry at each spaceport was done.