The Shuttlecraft Infinity was a small space vessel built by the Daystrom Institute, which served as the initial testbed for the transwarp drive project. In addition to its experimental transwarp engines, it also included a second fusion generator meant to reinforce the structural integrity field. In the year 2284, Torias Dax test-piloted the Infinity. Tragically, the shuttle broke apart before crossing the warp 10 threshold. (DS9 - The Lives of Dax short story: "Infinity")