Space flight experiment test results of a Space Station Active Rack Isolation System (ARIS) are presented. The purpose of ARIS is to isolate microgravity sensitive science experiments mounted in Space Station racks from structural vibrations present on the large Space Station orbital structure. The overall objectives of the experiment were 1) to test and evaluate the ARIS design modifications made from 1997 to 2000 as a result of prototype flight testing performed on the Space Shuttle Atlantis, 2) to characterize isolation performance on the International Space Station, 3) to assess the impact that rack payload disturbances have on the microgravity environment, 4) to test alternative umbilicals designed to improve isolation performance, and 5) to gain on-orbit operational experience and validate procedures. The scope of the material presented is limited to microgravity performance issues, so only results related to the first four objectives are presented. Over a year of flight testing was completed, and ARIS consistently has performed extremely well such that station vibrations were isolated to levels well below the science requirement.