  The volume available on small satellites restricts the size of optical
apertures to a few centimetres, limiting the Ground-Sampling Distance (GSD) in
the visible to typically 3 m at 500 km. We present in this paper the latest
development of a laboratory demonstrator of a segmented deployable telescope
that will triple the achievable ground resolution and improve photometric
capability of CubeSat imagers. Each mirror segment is folded for launch and
unfolds in space. We demonstrate through laboratory validation very high
deployment repeatability of the mirrors <{\pm}5 {\mu}m. To enable
diffraction-limited imaging, segments are controlled in piston, tip, and tilt.
This is achieved by an initial coarse alignment of the mirrors followed by a
fine phasing step. Finally, we investigate the impact of the thermal
environment on high-order wavefront error and the conceptual design of a
deployable secondary fitting inside 1U.
