This is a Descent Engine designed by Space Technology Laboratories as used on the Project Apollo Lunar Excursion Module (LM) to land on the Moon. The engine could be throttled between 1,000 and 10,000 pounds of thrust and was also the first gimballed and throttable rocket engine used on a spacecraft.
The engine shown here is an early developmental model dating to 1966. During the Apollo lunar missions from 1969-1972, there were no problems with the Descent Engine, although on the Apollo 13 mission, no Moon landing was made and the Descent Engine served another purpose, that of taking the craft out of lunar orbit and back home. The engine was donated to the Smithsonian in 1972 by the NASA Marshall Space Flight Center.
Transferred from the National Aeronautics and Space Administration