NX-Beta

The NX-Beta was one of three test vehicles, along with the NX-Alpha and NX-Delta, used by Starfleet's NX Project to test and refine the warp 5 engine designed by Henry Archer.

In 2143, Commanders Jonathan Archer, Henry Archer's son, and A.G. Robinson took the NX-Beta on an unauthorized flight shortly after the destruction of NX-Alpha. The vessel was able to reach a maximum speed of warp 2.5 by use of a manual intermix ratio control system, and return to Earth safely, the first Human vessel to do so. 

NX-Beta NX-Beta NX-Beta "NX-Beta"