Session

Technical Session 11: Propulsion

Location

Utah State University, Logan, UT

Abstract

The theory, experimentation, and implementation of a green monopropellant propulsion system for small satellites is described, including the environmental testing and integration of the system onto a CubeSat slated to launch in early 2022. HyPer, named after its propellant hydrogen peroxide, was specifically designed with the smaller size, lower power availability, and challenging launch conditions of CubeSats in mind. Instead of using a traditional monopropellant management system –pressurized reactive liquid forced to a catalyst bed – HyPer uses the vacuum of space to boil the stored liquid hydrogen peroxide, delivering a highly-tunable flow of reactive vapor to the catalyst. This lower flow rate enables HyPer to target the millinewton range of thrust without many of the hydrodynamic complications (e.g., droplet and bubble formation, and thermocapillary flows) that prevent full decomposition in low-thrust liquid systems. This thrust range allows for a wide variety of mission-enabling maneuvers for low mass systems, including (1) constellation management, (2) formation flying, (3) rendezvous, (4) extended mission durations, and (5) orbit reconfiguration. Due to the reaction at the catalyst bed, HyPer still retains the performance associated with a monopropellant system, which allows for a smaller total propulsion package.

The HyPer flight unit is exhaustively detailed from design decisions to performance metrics. There are several unique design elements due to the novelty of the concept. These include a propellant management device that controls the flow of vapor for propulsive activities and also allows for oxygen venting during long storage intervals, commercial-off-the-shelf components adapted for the harsh hydrogen peroxide environment, and a nozzle assembly designed to retain as much heat as possible in the catalyst bed. Performance was characterized by direct measurements of pressure, temperature, and mass flow rate in a vacuum environment. Launch survivability and on-orbit operability were verified with vibration, thermal cycle, leak rate, and life testing. On-board flight software and ground commanding were tested prior to integration to ensure appropriate timing and activation of safety features in case of an anomaly. HyPer’s checkout testing at different levels of satellite integration and propellant loading plan are also outlined.

Available for download on Saturday, August 07, 2021

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Aug 10th, 2:00 PM

HyPer - a Green Monopropellant for Small Satellite Propulsion

Utah State University, Logan, UT

The theory, experimentation, and implementation of a green monopropellant propulsion system for small satellites is described, including the environmental testing and integration of the system onto a CubeSat slated to launch in early 2022. HyPer, named after its propellant hydrogen peroxide, was specifically designed with the smaller size, lower power availability, and challenging launch conditions of CubeSats in mind. Instead of using a traditional monopropellant management system –pressurized reactive liquid forced to a catalyst bed – HyPer uses the vacuum of space to boil the stored liquid hydrogen peroxide, delivering a highly-tunable flow of reactive vapor to the catalyst. This lower flow rate enables HyPer to target the millinewton range of thrust without many of the hydrodynamic complications (e.g., droplet and bubble formation, and thermocapillary flows) that prevent full decomposition in low-thrust liquid systems. This thrust range allows for a wide variety of mission-enabling maneuvers for low mass systems, including (1) constellation management, (2) formation flying, (3) rendezvous, (4) extended mission durations, and (5) orbit reconfiguration. Due to the reaction at the catalyst bed, HyPer still retains the performance associated with a monopropellant system, which allows for a smaller total propulsion package.

The HyPer flight unit is exhaustively detailed from design decisions to performance metrics. There are several unique design elements due to the novelty of the concept. These include a propellant management device that controls the flow of vapor for propulsive activities and also allows for oxygen venting during long storage intervals, commercial-off-the-shelf components adapted for the harsh hydrogen peroxide environment, and a nozzle assembly designed to retain as much heat as possible in the catalyst bed. Performance was characterized by direct measurements of pressure, temperature, and mass flow rate in a vacuum environment. Launch survivability and on-orbit operability were verified with vibration, thermal cycle, leak rate, and life testing. On-board flight software and ground commanding were tested prior to integration to ensure appropriate timing and activation of safety features in case of an anomaly. HyPer’s checkout testing at different levels of satellite integration and propellant loading plan are also outlined.