In addition to launching of CubeSats to conduct bespoke measurements in support of national and regional businesses in New Zealand, CSST will conduct research to improve the quality and effectiveness of the CubeSat programme. Of particular interest here is the use of cold gas thrusters and electrical propulsion to better orient and extend the orbital range of CubeSats.
The initial satellites that CSST will design and build will most likely use a reaction wheel based control system to guide and control the CubeSats. As CSST progresses, we will research the ability to replace these control systems with a cold-gas thruster system, which is one of the most reliable methods for satellite orientation. Presently, the cold-gas thruster systems used on CubeSats are typically on the order of 25 mm × 90 mm × 90 mm, comprising 25% of the available space on a 1U satellite. The CSST research programme will aim to miniaturize this existing cold-gas thruster system to fit into the standardized CubeSat specifications.
Electrical propulsion is a much smaller control system than the cold-gas thrusters. For electrical propulsion, solar panels can be used to potentially provide not only orientation control, but also the ability to transfer the satellite to higher orbits. Therefore, the capability of CSST CubeSats would be dramatically enhanced as more tailored orbits could be achieved and even changed over time as required for each application. For example, by applying small pulses of acceleration over a long period, a 500 km orbit could be transformed into a 1000 km orbit to provide longer overpass times across New Zealand. The ability to push CubeSats into higher orbits after their ejection from the Electron orbital vehicle, would also extend the lifetime of CubeSats beyond the typical 3 years.
Additional research questions include:
- What is the minimum actuation required for orientation control of the CubeSats?
- How well do sensor systems integrate with CubeSats?
- What is the quality of the CubeSat data and can it be improved by using cold-gas thrusters?
- What is the impact of high elliptical orbits on CubeSat data generation?