The NX test ships were built as part of the program which led to the NX class Starship. They were the first Human-built vessels which exceeded warp factor 2, and later warp factor 3. The first warp 2 flight was made in 2143 by AG Robinson; the NX Alpha suffered a catastrophic accident at warp 2.2 and was destroyed, though Robinson managed to eject safely. The NX Beta subsequently achieved stable flight at warp 2.5. After a year of testing to prove the safety of the engine, tests resumed; eight months later Duvall achieved warp 3 in the NX Delta.

These flights proved the capability and safety of the warp engine designed by Henry Archer, allowing the Human race to mount true deep space interstellar missions for the first time.

• D728 Alpha NX
• D729 Beta NX
• D730 Delta NX
• D731 Gamma NX