Session
Session V: Propulsion-Enterprise
Location
Salt Palace Convention Center, Salt Lake City, UT
Abstract
The propellant grade hydrogen peroxide is coming back to space industry. While launcher applications would accept lower grades of High Test Peroxide (HTP) for cost reduction, the highest possible concentration matters much more for in-space propulsion. Every 1% in peroxide concentration translates to the propulsive performance (specific impulse) roughly in 1% for monopropellant and 0.5% for bipropellant.
The highest HTP grade provides certain advantages. While being more reactive, it requires less catalyst for its full decomposition, resulting in hardware mass and cost reduction. When used with any kind of bipropellant (either catalyst-augmented or hypergolic, and including hybrid), the highest grade HTP provides also the shortest possible ignition delay. However, decomposition temperature of 98% HTP has its price in a challenging catalyst technology. Pure silver, usually coated with samarium oxide, is no more applicable, even supported on e.g. nickel wire mesh. Ceramic supported platinum has been identified as very active and compliant with thermal requirements for 98% HTP. However, the brittle nature of microporous ceramics appeared to be a limiting factor for certain purposes.
While working with the European Space Agency (ESA) for over 10 years, the authors explored critical issues and requirements linked to space propulsion and understood how to work together to develop game-changing technologies for 98% HTP. Requirements, related to hydrazine catalysts, have been found challenging but motivating. Multiple iterative loops with conventional solutions for HTP and a failure in the identification of the right one indicated a different approach to this issue. A monolithic, fully-metal, macro-porous structure, coated with specially selected composition of active materials, appeared to be a perfect answer for 98% HTP. A three-dimensional, sponge-like metal foam ensures better mixing and reaction rate than any straight-channel cordierite catalytic insert and remains resistant to multiple cold starts. No movable parts means no abrasion and void creation. This affects the chamber pressure stability. Several ground demonstrations of this technology have proved its great potential. One of these includes over 20 kg of the propellant throughput with an in-house developed 1 N thruster. This demonstration combined up to 2 hour steady-state burns and over 10000 pulses of variable duration and frequency. The pressure roughness (3σ) has been maintained at the level of 1,5% from test to test. Good repeatability of transients and impulse bits has been achieved. Successful tests in a higher scale (200 times by mass flow rate) and with a higher bed loading proved the scalability of this technology.
The paper presents challenges encountered by the authors, approach, and methods applied to solve certain issues concerning propulsion technologies for 98% HTP. Test results with 1N monopropellant thruster and 420 N catalyst-augmented bipropellant engine have been discussed. The authors introduce their further development plan for an innovative, long-lasting and fast-response catalyst bed, considered as a game-changing technology. This scalable catalyst bed is applicable not only for monopropellant, but also for various types of bipropellant thrusters, including liquid and hybrid.
Document Type
Event
Game-Changing Technologies for Green Propulsion Operating With 98% Hydrogen Peroxide
Salt Palace Convention Center, Salt Lake City, UT
The propellant grade hydrogen peroxide is coming back to space industry. While launcher applications would accept lower grades of High Test Peroxide (HTP) for cost reduction, the highest possible concentration matters much more for in-space propulsion. Every 1% in peroxide concentration translates to the propulsive performance (specific impulse) roughly in 1% for monopropellant and 0.5% for bipropellant.
The highest HTP grade provides certain advantages. While being more reactive, it requires less catalyst for its full decomposition, resulting in hardware mass and cost reduction. When used with any kind of bipropellant (either catalyst-augmented or hypergolic, and including hybrid), the highest grade HTP provides also the shortest possible ignition delay. However, decomposition temperature of 98% HTP has its price in a challenging catalyst technology. Pure silver, usually coated with samarium oxide, is no more applicable, even supported on e.g. nickel wire mesh. Ceramic supported platinum has been identified as very active and compliant with thermal requirements for 98% HTP. However, the brittle nature of microporous ceramics appeared to be a limiting factor for certain purposes.
While working with the European Space Agency (ESA) for over 10 years, the authors explored critical issues and requirements linked to space propulsion and understood how to work together to develop game-changing technologies for 98% HTP. Requirements, related to hydrazine catalysts, have been found challenging but motivating. Multiple iterative loops with conventional solutions for HTP and a failure in the identification of the right one indicated a different approach to this issue. A monolithic, fully-metal, macro-porous structure, coated with specially selected composition of active materials, appeared to be a perfect answer for 98% HTP. A three-dimensional, sponge-like metal foam ensures better mixing and reaction rate than any straight-channel cordierite catalytic insert and remains resistant to multiple cold starts. No movable parts means no abrasion and void creation. This affects the chamber pressure stability. Several ground demonstrations of this technology have proved its great potential. One of these includes over 20 kg of the propellant throughput with an in-house developed 1 N thruster. This demonstration combined up to 2 hour steady-state burns and over 10000 pulses of variable duration and frequency. The pressure roughness (3σ) has been maintained at the level of 1,5% from test to test. Good repeatability of transients and impulse bits has been achieved. Successful tests in a higher scale (200 times by mass flow rate) and with a higher bed loading proved the scalability of this technology.
The paper presents challenges encountered by the authors, approach, and methods applied to solve certain issues concerning propulsion technologies for 98% HTP. Test results with 1N monopropellant thruster and 420 N catalyst-augmented bipropellant engine have been discussed. The authors introduce their further development plan for an innovative, long-lasting and fast-response catalyst bed, considered as a game-changing technology. This scalable catalyst bed is applicable not only for monopropellant, but also for various types of bipropellant thrusters, including liquid and hybrid.
