The Thunderbird, shown above, is the first test rocket to use a polysulfide solid fuel, developed by Charles Bartley at the Jet Propulsion Laboratory. The rocket test was conducted at Inyokern, California in November 1947. Al Richardson is seen on the left, with an unidentified employee on the right.
For more information about the Thunderbird test rocket, or about the history of JPL, contact the JPL Archives.