The fourth and fifth set of MISSE experiments (MISSE PEC3 and MISSE PEC4) were launched by , during mission STS-121, on 3 August 2006 and contained 875 specimens of various materials [REF].
MISSEs 3 and 4 also served an educational purpose, it flew approximately eight million basil seeds that were given to children for science experiments, in order to stimulate interest in space science [REF].