Active deployable primary mirrors on CubeSat

TL;DR

This paper presents a laboratory demonstrator of a deployable segmented primary mirror for CubeSats, significantly enhancing ground resolution and photometric capabilities by enabling larger apertures in small satellite platforms.

Contribution

The work introduces a novel segmented deployable telescope with high deployment repeatability and precise mirror control, advancing optical capabilities for CubeSat applications.

Findings

High deployment repeatability of <±5 μm demonstrated

Effective piston, tip, and tilt control achieved for diffraction-limited imaging

Thermal environment impacts on wavefront error analyzed

Abstract

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.