SOFA: System d'Orientation Fine d'Antenne (an antenna fin pointing) mechanism

The SOFA system is particularly suited to the transmit-and-receive antennae of television satellites. It is one of the requisites for a radiofrequency type deviation detector. The major characteristic of this system is complete freedom from friction and wear-out, resulting in numerous advantages, such as outstanding precision, virtually endless service life, high simplicity and reliability. The sizing method is described and performances are analyzed. The results from analogue simulations are presented. A functional model of the electrical and mechanical parts were built and subjected to on-ground tests using a 2 axis platform simulating the spacecraft's motions. The results obtained are in keeping with the predictions and simulations. Various possible applications of the SOFA system are mentioned.