Space Environmental Effects Experiments
Materials used on the exterior of spacecraft, satellites and space stations in low Earth orbit are subjected to many environmental threats which can cause degradation. Anything flown outside our atmosphere can be degraded by orbital debris, temperature extremes and, in low Earth orbit (LEO), atomic oxygen. Space environments affect flight experiments and test the stability and durability of materials and devices in the space environment.
There is also extreme ultraviolet radiation due to the lack of an atmospheric filter. This radiation deteriorates and darkens many plastics and coatings. The vacuum in space also alters the physical properties of many materials. Impacts of meteoroids and orbiting man-made debris can damage all materials exposed in space. The combined effects of all of these environments on spacecraft can only be investigated in space.
There have been several projects that test the effects of space on spacecraft materials.
America's first experimental space station was launched into Earth orbit on May 14, 1973 by a Saturn V rocket. Crews visited Skylab and returned to Earth in Apollo spacecraft. Three three-man crews occupied Skylab for a total of 171 days. Nearly 300 experiments were completed including experiments on human adaptability to zero gravity, on solar & Earth resources and on materials exposure in space environments.
The Mir Environmental Effects Payloads (MEEP) were attached for over a year to the Mir Docking Module of the space station Mir between shuttle flights STS-76 and STS-86.
NASA's Long Duration Exposure Facility (LDEF), which was retrieved in 1990 after spending 68 months in low earth orbit, was designed to provide long-term experimental data on the the outer space environment. LDEF revealed that space environments are very hostile to many spacecraft materials, components and operations. LDEF was designed to test reactions of various space building materials to radiation, extreme temperature changes and collisions with space matter.
The Materials International Space Station Experiment(MISSE) is a series of experiments mounted externally on the International Space Station (ISS) that investigates the effects of long-term exposure of materials to the harsh space environment. The MISSE project evaluates the performance, stability, and long-term survivability of materials and components planned for use by NASA, commercial companies and the U.S. Department of Defense (DOD) on future low Earth orbit (LEO), on synchronous orbit and on interplanetary space missions. MISSE is a direct successor of the Mir Environmental Effects Payloads (MEEP).