Mir Environmental Effects Payload

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.

Source: Wikipedia — Mir Environmental Effects Payload (CC BY-SA 4.0)