title: Hexapod.
abstract: SAGE III (Stratospheric Aerosol and Gas Experiment), an Earth-observation instrument developed by NASA's Langley Research Center (LaRC), was one of the first scientific external payloads selected for the International Space Station. It was conceived to fly on a spacecraft able to provide +/- 1 degree pointing accuracy. Since the ISS's attitude can vary by several degrees over a long period, it was therefore necessary to provide a dedicated nadir-pointing system. For this task, NASA selected the hexapod-based pointing system ("Hexapod" for short) included by ESA in the list of proposed European contributions to the ISS early utilisation phase. Launch is currently scheduled with assembly flight UF-3, although this could be modified by revisions in the ISS assembly sequence.
mesh_terms: D055580:Astronomical Phenomena; D001256:Astronomy; D001272:Atmosphere / Q000032:analysis*; D018534:Earth, Planet; D004784:Environmental Monitoring / Q000295:instrumentation; D004867:Equipment Design; D005060:Europe; D007390:International Agencies; D013026:Space Flight / Q000295:instrumentation*; D018531:Spacecraft / Q000295:instrumentation*; D013057:Spectrum Analysis; D014481:United States; D018557:United States National Aeronautics and Space Administration; D014893:Weightlessness