The 2009 update to the Lightning Launch Commit Criteria

This paper will summarize the 2009 updates to the Lightning Launch Commit Criteria (LLCC). These updates made substantial changes to the LLCC for anvil clouds and for convective debris clouds and refined several of the definitions. The LLCC are a set of weather rules to avoid natural and rocket triggered lightning to in-flight rockets. They are very complex and are very different from most other operational weather support. The LLCC may now be the leading weather cause of launch delays and scrubs from Cape Canaveral Air Force Station and NASA Kennedy Space Center. The same LLCC are used for space launches from the U.S., such as by the US Air Force, NASA, commercial spaceports regulated by the FAA. Many atmospheric phenomena generate electric fields that are sufficiently strong for rocket triggered lightning, but are not strong enough to cause natural lightning. Even stratus clouds can have sufficiently strong electric fields for rocket-triggered lightning, if they are thick enough and reach the correct temperature level.