 The LDF structure was built at NASA Langley Research Center and shipped to Kennedy Space Center in 1983 where experiments were mounted to it in preparation for launch. These experiments and the structure itself were designed to better define and determine the effects of the low earth orbit environment where man may someday live as he extends his exploration of the solar system. The advent of LDF, NASA's Long Duration Exposure Facility, took place in April of 1984. It would become one of NASA's most successful satellites. The first spacecraft ever to take advantage of the space shuttle's unique capability to deploy experiments in space for long exposure times and then return them safely to earth for laboratory analysis. Using a remote manipulator arm, Terry Hart lifted the LDF from the shuttle cargo bay and placed it in the proper position for free flight in space. The LDF's initial orbit was 257 nautical miles above the earth and inclinated at 28 and one-half degrees. As it orbited in free flight, one end always pointed toward space, the other always pointed toward the center of the earth. For five and one-half years, LDF would carry 57 experiments in 86 trays mounted on its exterior. It would be the only source of data to measure the effects of prolonged space exposure on spacecraft materials and living organisms. The retrieval of LDF in January of 1990 marked the beginning of scientific investigation for the more than 200 researchers and scientists who had launched their experiments five and one-half years earlier. This time, astronaut Bonnie Dunbar operated the manipulator arm while astronaut Marsha Ivins took the first investigative photographs. Ten thousand specimens in virtually every part of the facility will provide information about what happens when things stay in space for long periods of time. The facility and experiments will provide unprecedented data on the magnitude of induced radioactivity in materials during prolonged exposure in space. The interstellar gas experiment will provide insight into the formation of the galaxies as captured interstellar gas atoms are analyzed. Cosmic dust experiments will provide insight into the evolution of the solar system through studies of the unparalleled quantity of captured micrometeoroid material. Radiation experiments will provide data on radiation intensity and its effects on living organisms. Studies of thousands of materials associated with design of spacecraft structures, thermal control systems, power systems, optics, electronic systems, and propulsion systems will be analyzed for environmental effects of radiation, vacuum, extreme temperature variations, atomic oxygen, and collision with space materials. Eventually, all spacecraft and spacecraft systems will be designed using materials that have been validated for long-duration space exposure. For the remainder of the mission, LDF was safely tucked away in the Space Shuttle's cargo bay. It remained there through the shuttle landing at Edwards Air Force Base and the piggyback ride to the Kennedy Space Center. In the Orbiter Processing Facility, investigators got their first glimpse of LDF. Initial examinations focused on the interrelationship of all experiments and the LDF structure. Then the experimental trays were removed and distributed to investigators for data analysis. The science experiments hold exciting revelations regarding the evolution of the cosmos and biological effects on long-duration space exposure as they relate to the presence of humans in space. LDF technology experiments will establish a database for use in designing spacecraft, such as Space Station. The most publicized experiment is SEEDS, which offers a wide variety of opportunities for student experiments. Twelve and one-half million SEED packages were distributed to upper elementary through university-level students. American students and students of foreign countries have become interested in science and the scientific method of investigation by growing and comparing tomato plants from control seeds which are kept on Earth and experimental seeds which were housed on LDF as it orbited the Earth. LDF and its experiments are just beginning to define and determine the effects of the lower Earth orbit environment. As investigators interpret their data, they grow confident in the models they are using to accurately predict this environment. All space vehicles that fly in Earth orbit will benefit from LDF. Space Station Freedom will be its first major benefactor. The LDF structure designed for reuse may be available for use on future LDF missions.