These are sections of a hand wheel from Rocketdyne's Vertical Test Stand No. 1 (VTS-1) at its Santa Susana Field Laboratory in the Santa Susana Mountains, California. VTS-1 was an important site used by Rocketdyne and its predecessor from the 1950s for the testing the U.S.'s first large-scale liquid propellant rocket engines, starting with the Redstone missile engine. The wheel may have been used to open water tanks to cool down the stand after each firing.
The Redstone engine evolved into the engines for the Thor, Jupiter, and Atlas missiles, the engines for the Saturn V launch vehicle that took men to the Moon, and the Shuttle Main Engine.
This object was donated to the Smithsonian in 1996 by Rocketdyne.