Microgravity Environment on the International Space Station

ABSTRACT The International Space Station is being assembledon-orbit to serve as a research platform for the nexttwenty years. A primary feature of this research platformwill be its microgravity environment – an environment inwhich the effects of gravity are drastically reduced. Aphysical environment with very low-levels ofacceleration and vibration has been accomplished byboth the free fall associated with orbital flight and thedesign of the International Space Station. TheInternational Space Station design has been driven by along-standing, high-level requirement for a microgravitymode of operation. Various types of data are gathered when scienceexperiments are conducted, with common variablesbeing temperature, pressure, voltage, and power. Theacceleration levels experienced during operation shouldbe factored into the analysis of the experiment results ofmost microgravity experiments. To this end, the NASAFundamental Microgravity Research in the PhysicalSciences program has had the Space AccelerationMeasurement System recording the acceleration levelsto support microgravity researchers for over twelve yearsof Shuttle missions, three years on Mir, and now nearlythree years of International Space Station operations. The Fundamental Microgravity Research in thePhysical Sciences program also supports the PrincipalInvestigator Microgravity Services project to assist theprincipal investigators with their analysis of theacceleration (microgravity) environment. The PrincipalInvestigator Microgravity Services project providescataloged data, periodic analysis summary reports,specialized reports for experiment teams, and real-timedata in a variety of user-defined formats.Characterization of the various microgravity carriers(e.g. Shuttle and International Space Station) is alsoaccomplished for the experiment teams. In the future, the Principal Investigator MicrogravityServices project will provide a detailed predictiveanalysis of the microgravity environment for particularpayloads in specified locations. This will assist greatly inthe operational payload planning process. In addition, aneural-network-based system is planned which willautomatically interpret the environment in real-time andpresent the results to users in an easily understoodformat. Presented in this paper will be a short description ofhow microgravity disturbances may affect someexperiment classes, a snapshot of the microgravityenvironment, and a view into how well the space stationis expected to meet the user requirements. ABBREVIATIONS AND ACRONYMS