The Preliminary Thermal Design for the SPEQTRE CubeSat

CubeSats are now experiencing a strong demand for advanced scientific and technological performances which is increasing the value of heritage, accessible thermal flight data and high readiness technologies, on top of miniaturization and modularity challenges. This compels us to pay extra attention to their thermal management. In addition, the procedures and guidelines typically used for the thermal design of space systems are often inadequate for CubeSats, which result in over or under-sized thermal control systems. The Space Photon Entanglement Quantum Technology Readiness Experiment (SPEQTRE) CubeSat is a mission to demonstrate quantum key distribution which can secure communications between space systems and Earth ground segments. This project emerged from an international collaboration between RAL Space, part of the UK Science and Technology Facilities Council (STFC), and the Centre for Quantum Technologies (CQT) hosted by the National University of Singapore (NUS). Whilst CQT is responsible for the quantum source on the satellite and quantum receiver on the ground station, RAL Space is responsible for the optical payload, the spacecraft platform and the ground station at Chilbolton (UK). This paper describes how we are approaching the thermal design for the overall SPEQTRE CubeSat mission and how we are meeting the challenges and opportunities of supporting collaborator furnished systems. Bringing together CubeSat and quantum communication technologies requires stringent specifications. In addition, the required thermal management has a major impact on the scientific performance. The main thermal challenges are the thermal environment in Low Earth Orbit (LEO), the high power density, the required thermal stability and uniformity, and the thermal design flexibility. Launch is scheduled for Q1/Q2 2023.