With this thrust, the engine has a thrust-to-weight ratio of 51.2, and a specific impulse of in a vacuum and at sea level.
Aerojet Rocketdyne RS-68 (prej Rocketdyne in kasneje Pratt & Whitney Rocketdyne) je tekočgorivni raketni motor, ki uporablja za gorivo tekoči vodik (LH2) in za oksidator tekoči kisik (LOX).