The U.S. space program is responsible for a number of facilities with metallic structural and nonstructural
components in highly and moderately corrosive environments. To protect against the effects
of corrosion, such structures are commonly covered with a coating system consisting of a zinc primer,
intermediate coating, and topcoat. The most common topcoats used in such systems are
polyurethanes that contain isocyanates and other hazardous materials. Their use, however, is being
threatened by safety and environmental concerns and increasing regulations. In order to ensure
mission readiness while reducing environmental and safety risks, the National Aeronautics and Space
Administration (NASA) partnered with Headquarters Air Force Space Command (AFSPC) to
demonstrate/validate environmentally preferable coating systems for use on steel substrates used on
launch pads, test stands, and ground support equipment. This paper will present the results and
conclusions from the laboratory and field testing. The study revealed at least two isocyanate-free
coating systems that performed similar or better than the control coatings.