Engine will produce 26 hp.

Boeing and Lockheed Martin have reportedly tapped Roush Industries to build a unique engine for its United Launch Alliance program.

According to The Drive, the aerospace titans have tapped the Metro Detroit firm to build an "Integrated Vehicle Fluids" flathead straight-six engine which has a displacement of just 600cc.  The 26 horsepower engine will measure just 27.5 inches long and weigh about 100 pounds.  It has also been designed to be cost effective so it will use a number of readily available parts including piston rods, spark plugs, and a coil pack from General Motor's 5.3-liter V8 engine.

The engine will be used on the Advanced Cryogenic Evolved Stage (ACES) rocket which is currently being developed.  It will reportedly pressurize the rocket's fuel tanks, recharge batteries, and provide attitude control.  If everything goes according to plan, the engine will enable the rocket to operate in space for weeks at a time.

The rocket is reportedly being designed as part of an ambitious program which intends to send as many as a 1,000 astronauts into space by 2045.

Source: The Drive