Triggered lightning risk assessment for reusable launch vehicles at four regional spaceports

DTRT57-05-D-30103, Task 13A
FA2R/DL411
The Aerospace Corporation was tasked by the Volpe National Transportation Systems Center to provide technical support to the Federal Aviation Administration, Office of Commercial Space Transportation, in assessing the risks involved with triggered lightning during
suborbital launches and reentries of reusable launch vehicles (RLVs) from four regional spaceports, viz., Spaceport America in New Mexico, the Oklahoma Spaceport, the Mojave Air and Space Port in California, and the West Texas Spaceport. Risk of triggered
lightning was studied for four conceptual RLVs originating and/or landing at these spaceports. Five areas were addressed: (1) observed frequencies of natural cloud-to-ground lightning at four spaceports, including data from two existing lightning-mapper arrays, plus estimates of violation frequencies of the other existing lightning flight commit criteria (LFCC), (2) literature summary and new approximate analysis of the effective conducting length of the vehicle plumes, (3) review of the current LFCC to determine if the criteria are relevant to each suborbital RLV concept, including an evaluation of local geographical effects pertaining to each spaceport to determine whether additional LFCC are necessary to conduct safe launch operations there, (4) evaluation of risk based on airborne electric field measurements and cloud, temperature and lightning data, and (5) evaluation of an aircraft icing index as an indicator of high electric fields in clouds at sites that are not instrumented with weather radars and temperature sounders.