The WD-1 was an experimental Earth spacecraft in used in 2055 SFC and 2056 SFC to test a prototype practical warp drive based on the theories of Centauran physicist Zefram Cochrane.
In 2055 SFC, on its first test run, WD-1 famously reached a warp factor of 1.5 -- traveling some 10 million kilometers across the near-Pluto test area in just 10 seconds.
The same flight was also a practical test of the potential effects of space warp on living beings. A chimpanzee named Rosy flew aboard the WD-1, and proved that higher life forms could travel at warp without ill effects. (TOS reference: Spaceflight Chronology)