The US Department of Energy and the National Nuclear Security Administration (NNSA) have announced a success in a nuclear fusion experiment at the Lawrence Livermore National Laboratory’s (LLNL) National Ignition Facility (NIF). A system of 192 lasers emitted 2.05 megajoules of energy by focusing it on a tiny gold cylinder containing a pellet of deuterium and tritium. The energy from the lasers created conditions similar to those in a stellar core by triggering nuclear fusion and generating about 3.15 megajoules of energy. Obtaining more energy than emitted is an important step in using nuclear fusion as an energy source but a lot remains to be done to build fusion nuclear power plants.