  The need for both high quality images and lightweight structures is one of
the main drivers in space telescope design. An efficient wavefront control
system will become mandatory in future large observatories, retaining
performance while relaxing specifications in the global system's stability. We
present the mirror actively deformed and regulated for applications in space
project, which aims to demonstrate the applicability of active optics for
future space instrumentation. It has led to the development of a 24-actuator,
90-mm-diameter active mirror, able to compensate for large lightweight primary
mirror deformations in the telescope's exit pupil. The correcting system has
been designed for expected wavefront errors from 3-m-class lightweight primary
mirrors, while also taking into account constraints for space use. Finite
element analysis allowed an optimization of the system in order to achieve a
precision of correction better than 10 nm rms. A dedicated testbed has been
designed to fully characterize the integrated system performance in
representative operating conditions. It is composed of: a telescope simulator,
an active correction loop, a point spread function imager, and a Fizeau
interferometer. All conducted tests demonstrated the correcting mirror
performance and has improved this technology maturity to a TRL4.
