FSPA and BSMA Nanometric positioning actuators for ground and space applications

Many applications and more specifically space projects show need for a stable sub-micrometre positioning actuator. In order to meet this need, Cedrat Technologies has designed the new FSPA brand. This linear stepping actuator offers sub-micrometric positioning resolution along 5mm stroke combined with high actuation force (>100N) and the ability to hold its position without power.
The IASI-NG instrument is one of the key payload on-board METOP-SG which is a new meteorological satellite for Europe. The instrument is based on a Mertz interferometer and requires a very precise positioning of an optical blade used to separate the interferometer’s branches. A dedicated version of the FSPA, the Beam Splitter Mechanisms Actuator (BSMA) is then developed to achieve this nanometric positioning which is a key parameter for the overall instrument performance.
This paper firsts present the internals of both FSPA and BSMA actuators. Major design differences and their respective impact on the resulting performances are detailed. Results from the acceptance and qualification test campaigns are also presented.