This is a Space Shuttle Columbia (STS-52) onboard photograph of the United States Microgravity Payload-1 (USMP-1) in the cargo bay. The USMP program is a series of missions developed by NASA to provide scientists with the opportunity to conduct research in the unique microgravity environment of the Space Shuttle's payload bay. The USMP-1 mission was designed for microgravity experiments that do not require the hands-on environment of the Spacelab. Science teams on the ground would remotely command and monitor instruments and analyze data from work stations at NASA's Spacelab Mission Operation Control facility at the Marshall Space Flight Center (MSFC). The USMP-1 payload carried three investigations: two studied basic fluid and metallurgical processes in microgravity, and the third would characterize the microgravity environment onboard the Space Shuttle. The three experiments that made up USMP-1 were the Lambda Point Experiment, the Space Acceleration Measurement System, and the Materials for the Study of Interesting Phenomena of Solidification Earth and in Orbit (MEPHISTO). The three experiments were mounted on two cornected Mission Peculiar Equipment Support Structures (MPESS) mounted in the orbiter's cargo bay. The USMP program was managed by the MSFC and the MPESS was developed by the MSFC.