Light Microscopy Modle, LMM, Ground Unit Testing, GU. Control Systems Engineer using a small magnet to maneuver a 1mm metal stir-bar into a colloid sample fluid-filled capillary. The capillary tubes of sample fluid will be filled and sealed. The sample fluid supplied by a Principal Investigator typically contains some hazardous/toxic chemicals that she must ensure will not leak and put the astronauts at risk. On-orbit on the LMM, ‘insitu mixing’ is used, which uses electromagnetic inductors to stimulate the metal stir-bar to mix the fluid within the sealed capillary.