I am curious about how much potential would a hybrid (electric & chemical) micropropulsion system have for CubeSats.
The chosen propellant is water due to its non toxic nature, cheap cost and high Delta-V. Besides, it can be disassociated, by applying external electrical power, into hydrogen and oxygen. These two would react in a combustion chamber (chemical propulsion).
Nanosatellites such as CubeSats impose strict requirements in terms of mass, volume, and power. These are the restrictions I am thinking to impose on the micropropulsion system ONLY: 0.7 Kg as the maximum total wet mass of the system, a 1U size for the micropropulsion system (100 mm X 100 mm X 100 mm) and 7 W as maximum power required to make the system work.
The CubeSat performance requirements set by ESA are as follows
Now the question is what electric and chemical propulsion systems shall we choose to be combined. I propose
- Micro-resistojet (Electric propulsion). It vaporizes liquid water to a high temperature vapor for expulsion via a conventionally shaped nozzle, and has a wide potential for in-orbit maneuvers of nano-satellites. The general structure of the thruster is based on a modular design with three main parts: inlet section, heating chamber and nozzle. Biggest advantage: high Isp. Biggest drawback: low thrust.
- Bipropellant system (Chemical Propulsion). Combustion of an oxidizer (oxygen) and a fuel (hydrogen) are utilized to create a high-temperature, high-pressure gaseous mixture that can be expanded using a converging–diverging nozzle to create a high velocity exhaust stream. Bipropellant systems feature the highest performance for chemical systems per stored propellant, but require generally complex propellant managements system with multiple active components. Biggest advantage: higher thrust and performance among all chemical propulsion systems. Biggest disadvantage: complexity.
Do you think it is feasible to combine those propulsion systems within CubeSat constrains?
Thank you in advance! ;)