Sandia National Laboratories' Z-Machine plays a key role in NNSA’s mission to assure the reliability and safety of our nuclear stockpile as it ages. Z-Machine allows scientists to study materials under conditions similar to those produced by the detonation of a nuclear weapon, and produces key data used to validate physics models in computer simulations. Researchers can use Z-Machine to study the effects of nuclear radiation on different materials and under varying conditions to understand how to validate and secure U.S. weapons. Z-Machine just reached an important milestone: the 3,000th shot in support of stockpile stewardship.