Helium fusion enhancement was a concept in which a dying star could be revitalized.
In 2367, the USS Enterprise-D conducted a test on the Praxillus star using specially-modified photon torpedoes, designed by Kaelon scientist Timicin. Due to the similarities of the Praxillus star and the Kaelon sun, the test was designed to determine if the same process could be performed on the dying Kaelon sun, thereby saving the Kaelon people. The photon torpedoes successfully reached Praxillus's core, and at first it appeared that the experiment was successful. The star's temperature continued to increase, however, and the star exploded. (TNG: "Half a Life")