The Aquarius/SAC-D observatory was launch in June 2011 from Vandenberg Air Force Base (VAFB), in California,
USA. This mission is the fourth joint earth-observation endeavor between NASA and CONAE. The primary objective
of the Aquarius/SAC-D mission is to investigate the links between global water cycle, ocean circulation and climate by
measuring Sea Surface Salinity (SSS). Over the last year, the observatory successfully completed system level
environmental and functional testing at INPE, Brazil and was transported to VAFB for launch operations. This paper
will present the challenges of this mission, the system, the preparation of the spacecraft, instruments, testing, launch, inorbit
checkout and commissioning of this Observatory in space.