NASA has begun shaping Project Prometheus — harnessing nuclear energy to usher in a new era of Solar System exploration. Government agencies are powering up to support the effort. U.S. aerospace firms have started assessing how to build nuclear-powered probes. And scientists are sketching out an unprecedented “power-rich” research agenda using potent suites of space science instruments. Yet Prometheus is not without its detractors. Opponents see the program as dangerous and risky, dismissing it as a front for military star warriors.