The Explorer 23 micrometeoroid satellite (S 55C) was the third in the series of S 55 micrometeoroid satellites orbited by NASA. Its purpose was to obtain data on the near-Earth meteoroid environment, and provide an accurate estimate of the danger posed to spacecraft structures by meteoroid penetration. The cylindrically shaped spacecraft, about 61 cm in diameter and 234 cm long, was built around the spent fourth stage of the Scout launch vehicle, which remained as part of the orbiting satellite. Explorer 23 carried stainless steel pressurized-cell penetration detectors, impact detectors, and cadmium sulfide cell detectors to obtain data on the size, number, distribution, and momentum of dust particles in the near-earth environment. In addition, the spacecraft was designed to provide data on the effects of the space environment on the operation of capacitor penetration detectors and solar-cell power supplies.
This artifact is a portion of the backup spacecraft for Explorer 23. It was transferred to the Museum from NASA, Langley Research Center in 1979.