The accelerometer shown here is from France's National Office for Aerospace Studies and Research (Office National d'Etudes et de Recherches Aerospatiales - ONERA). It was developed for use in a proposed joint US-French mission called ARISTOTELES (which was not selected for flight). It used a rectangular proof mass 4cm x 4 cm x 1cm in dimensions rather than a sphere. The accelerometers being developed from LISA can be derived from existing space qualified electrostatic accelerometers such as this.