Astro III was the third in a series of Astro concepts, with Astro I bowing in 1967, and the XP-880 Astro II released the following year.
Powerplant for Astro III was the Model 250-C18 gas turbine engine produced by the Allison Division of General Motors. This engine was selected because of its lightweight and high power output. It weighed only 139 pounds and produced 317 net horsepower.
Though many tricycle-type automobiles have been produced over past years, none of them have been completely acceptable with regard to their handling. The key to good stability of a tricycle-type vehicle is the placement of the center of gravity. As the distance between the front tires or tread is reduced, the same resistance to rollover can be maintained by lowering the center of gravity through design and component location. These two technological conditions of aerodynamic efficiency and dynamic stability were necessary to resolve before proceeding with the Astro III design.