Mir Environmental Effects Payload

NASA materials science experiments aboard the Russian space station

The ''Mir Environmental Effects Payload (MEEP''') was a set of four experiments installed on the Russian space station Mir from March 1996 to October 1997 to study the effects of space debris impacts and exposure to the space environment on a variety of materials. The materials used in the experiments were being considered for use on the International Space Station, and by exposing them at a similar orbital altitude to that flown by the ISS, the experiments provided an assessment of the performance of those materials in a similar space environment. and retrieved during STS 86. Components

MEEP consisted of four separate experiments mounted in four separate Passive Experiment Carriers (PEC) installed on Mirs docking module. Each PEC consisted of three components; the experiment carrier, which contained the experiment itself, the sidewall carrier, which kept the PEC secure in the payload bay of the space shuttle during launch and return, and the handrail clamp, which was used to attach the PEC to the docking module. The first experiment, Polished Plate Micrometeoroid and Debris (PPMD), consisted of gold, aluminium, and zinc plates and studied how often space debris hit the station, the sizes and sources of the debris, and the damage the debris might do on hitting a space station. The second, the Orbital Debris Collector (ODC), captured orbital debris in aerogel cells for return to Earth to determine the possible origins and components of that debris. The last two experiments, Passive Optical Sample Assemblies I (POSA I) and II (POSA II), tested various materials intended for use on the International Space Station including paint samples, glass coatings, multilayer insulation, and a variety of metallic samples.

MEEP was designed to assess the magnitude of molecular contamination in ISS critical exterior surfaces in the space environment and to quantify the performance and degradation rate of candidate and selected ISS exterior surface materials. NASA's Langley Research Center had overall responsibility for MEEP as well as the development of the Passive Equipment Carriers as well as the PPMD experiment. The experiments were then inspected and studied by teams of space environmental effects investigators for micrometeoroid and space debris effects, space exposure effects on materials, and electrical performance. Also MEEPS can trace their inception to the Passive Optical Sample Array (POSA) sample trays flown on STS 1 and STS 2, and their successor Effects of Oxygen Interaction with Materials (EOIM) on STS 3 and STS 5.