This is the fuel hardstand and fuel holding trailer. In a fuel loading operation a commercial tank truck containing fuel (Aerozine 50, a mix of hydrazine and unsymmetrical dimethylhydrazine) would pull up along side and off-load its contents into the holding trailer. The fuel was then heated or cooled until it reached 60° F (15.5° C) and then flowed by gravity into the missile via large braided hoses. Propellant loading or unloading operations are refered to as “PTS operations.” PTS means propellant transfer system. Oxidizer is loaded and unloaded from a similar hardstand on the north side of the silo.