ESA GNC Conference Papers Repository

Proteus satellite bus was initiated by CNES and Thales Alenia Space end of 1996. The goal was to design and qualify a low-cost small platform for Low Earth Orbit payloads in the 300 kg/300 W class, as well as generic ground segment to perform scientific missions. This was achieved with the launch of six satellites from 2001 to 2016, with missions ranging from oceanography (JASON1, 2 and 3), to cloud and aerosol observation (CALIPSO), exoplanet search and asteroseismology (COROT), and soil moisture and oceans' salinity observations (SMOS). These missions were led by CNES and other agencies. The paper will briefly introduce PROTEUS bus architecture and give an overview of the six different missions. It will present more in detail JASON 3 mission objectives and satellite. Launched on January 17, 2016, from Vandenberg, by a Falcon 9 launcher, this satellite is the last one of the PROTEUS family and represents the fourth mission in U.S.-European missions that measure the height of the ocean surface. JASON3 is an international cooperation between CNES, NASA, EUMETSAT and NOAA. Then, the paper will focus on the generic PROTEUS AOCS design and highlight AOCS in-flight results during JASON3 Low Earth Orbit and assessment phases. During LEOP and assessment phase AOCS activities were more intense than foreseen due to unexpected events, but ended successfully in the end. The paper will explain these unexpected events, recovery actions and work-arounds. It will also describe in-flight final performance validation. The last part will make a synthesis and give the lessons learnt regarding PROTEUS AOCS behavior after more than 40 years cumulated in orbit, and four still operating satellites (JASON2 and 3, CALIPSO, SMOS).