Hexapod Pointing System on-board Nasa SAGE III instrument

SAGE III is a NASA instrument produced as part of the EOS (Earth Observing System) programme to measure the components of the Earth’s atmosphere, such as pressurised and ozone gas, ranging between the troposphere and the stratosphere. Moreover, SAGE III provides overall measurements of the temperature in the stratosphere, reporting traces of gas as water vapour and nitrogen dioxide, key elements to study the atmosphere and the relative climatic changes of the Earth. Thales Alenia Space, a joint venture between Thales (67%) and Leonardo (33%), plays an important role in this project. In its capacity as the prime contractor party on behalf of the European Space Agency, it has supplied the Hexapod Pointing System with the function of providing a platform for the SAGE III instrument. In addition to the system-related activities, developed in the Turin plant, certain parts of the flight system have been designed and built (Wiring, Thermal Control System, Software, Control Algorithms, etc…,) as well as prototypes, simulation systems and support systems. Hexapod is a pointing system that can compensate for the instability of the Space Station and guarantee a finely-tuned, stable pointing device for the scientific instrument that uses it. The system mainly consists of a pointing mechanism (Hexapod Pointing Assembly) made up of a platform driven by six electro-mechanical actuators, controlled and checked by an electronic unit (Hexapod Electronic Unit) and by complex software (Application SoftWare) that has been developed especially for this mission. The Hexapod Flight Unit has been developed to support NASA scientific instruments called SAGE. It has been delivered fully qualified to NASA in 2015, and then assembled and tested in the SAGE/Hexapod Integrated Payload by NASA LaRC with TAS support. NASA LaRC is the Payload Integrator and is the responsible of the complete flight mission. Thales Alenia Space plays a significant role in this ambitious International Space Station project. Not only does it contribute over 50% in the production of pressurised modules and in the construction and integration of the PCM Cygnus Cargo transport modules, it also develops several systems used by the ISS, both internally and externally, to carry out and provide support for different types of scientific experiments.