TopSat is a high resolution space camera, developed by RAL Space, which takes images with 2.5m pixels from 600km orbit height. It is also very compact and light which allows it to be carried onboard a microsatellite giving a very low cost solution with high performance.
The system comprises a push-broom imager based on a three-mirror off-axis telescope, fitted with a long, linear, Charge Coupled Device (CCD) detector in its focal plane. To achieve image resolution of this order from space requires highly accurate alignment of the optical system and extremely stable support structures for the optical components.
Positional accuracies of about 10 microns in the placement of components are needed and must be maintained throughout launch and subsequent operation in space.
Optical Systems within RAL Space designed the optical system and focal plane electronics. The telescope was aligned using complex opto-mechanical alignment techniques involving CMM and interferometry.
Further TopSat technical information can be found here.