The next generation of CubeSat orbit transfer

Every year NASA sends out requests for proposals from small business through their SBIR program. This system allows for small companies to gain funding to develop their ideas for potential future use. This year I sent in a proposal for their topic on CubeSat orbit transfer system.

The system that I am proposing would allow for CubeSats up to almost 100kg to transfer to the orbit that is being tested during the NASA CAPSTONE mission (NRHO). The way this system can achieve this is by using Nuclear Thermal Propulsion (NTP). NTP systems use Nuclear fission to generate heat, this heat is then absorbed by a coolant gas to both help control the reactor temperature while also providing high ISP thrust. The ISP range for most NTP systems is 900s to 1000s.

This transfer system will sacrifice the ISP to improve the total system volume by using decomposed Hydrazine instead of the typical coolant gasses. This would reduce the ISP to around 800s, but it will reduce the storage volume and complexity since Hydrazine is easy to keep as a liquid at room temperature. The target thrust is 50N.

The proposed process is to first decomposed Hydrazine through a catalyst to generate Hydrogen and Nitrogen, this gas will be hot when entering the reactor but the control drums should be able to control the reaction to prevent overheating. With the target thrust of 50N, and knowing the expected gas composition and inlet temperature, the reactor would only need to output 12kW. This is similar in size to the KRUSTY system that was tested to verify power generation on the Moon and Mars.

The hope is that funding can be acquired either through SBIR funding or through private investments to refine the design, test the system, and fly the first NTP system on orbit.