18,000 mph gas gun makes 200+ shots to modernize US nuclear stockpile

The Joint Actinide Shock Physics Experimental Research (JASPER) facility recently achieved a milestone with its 201st full-containment experimental shot, marking over 22 years of operation since its first actinide experiment in 2003. Central to these experiments is a 65-foot, two-stage gas gun capable of launching projectiles at speeds up to 18,000 miles per hour (8 km/s), generating pressures millions of times greater than atmospheric pressure for less than a microsecond. These tests primarily investigate how plutonium and other dense radioactive materials respond to shock compression, providing critical data that supports the National Nuclear Security Administration’s (NNSA) computational models used to verify the U.S. nuclear stockpile without underground testing. Operated jointly by Lawrence Livermore National Laboratory and the Nevada National Security Sites, JASPER’s focus has evolved from initial Hugoniot and thermodynamic measurements to a broader dynamic materials science scope, including temperature, strength, and release-wave studies. This