Commercially Available Imaging Payloads for CubeSat Earth Observation Missions

Abstract

CubeSats have many advantages for Earth observation, as platforms for scientific payloads with expanded spatial coverage and improved temporal resolution measurements through their operation in constellations. However, the development of custom miniaturized imaging payloads for the size, weight, and power constraints (SWaP) of CubeSats can be complicated and costly. This project evaluates currently available commercial-off-the-shelf (COTS) cameras for use as CubeSat-borne Earth observation imagers. This study is conducted in line with the mission requirements of a 3U CubeSat research project focusing on coastal imaging. We perform trade studies on COTS cameras for visible (VIS) and long wave infrared (LWIR) imaging. A radiometric link analysis of camera performance provides an estimate of the achievable signal-to-noise ratio (SNR) from low Earth orbit (LEO). We present results for select VIS and LWIR cameras, and our radiometric link analysis tool has been made available open-source. For example, we find that for a CubeSat in a 400 km orbit, featuring a VIS imager with a 11.4 mm aperture and 0.500 ms exposure, targeting a 443 nm center wavelength with 10 nm bandwidth, COTS cameras can provide SNRs ranging from 12.62 to 16.40 dB. As calibration and validation are critical for producing meaningful science data, we discuss our ground testing and onboard calibration approach using vicarious and in-situ methods.