sentences:  HiPER was designed to study the "fast ignition" approach to generating nuclear fusion, which uses much smaller lasers than conventional ICF designs, yet produces fusion power outputs of about the same magnitude.This offers a total "fusion gain" that is much higher than devices like the National Ignition Facility (NIF), and a reduction in construction costs of about ten times.This opened a window for a small machine to be rapidly built that would reach ignition before NIF.