Development of a Cold Gas Propulsion System for the ... - SSL - MIT

Hydrogen peroxide at the concentrations needed for use as a rocket propellant is far less readily
available. The hydrogen peroxide available in drugstores for cosmetic and antiseptic purposes is
generally at only 3% concentration in aqueous solution, hydrogen peroxide for laboratory use is
available at 30-35% concentration, and concentrations from 50 to 70% are used for many industrial
purposes such as bleaching of textiles and paper, but propellant-grade hydrogen peroxide ranges in
concentration from 70 to 98% [33]. This presents two difficulties that were identified during this trade
study between propellant system types. Firstly, at the time the work described in this thesis was being
performed, few companies offered hydrogen peroxide for sale at propellant-level concentrations,
though there was at least one supplier (FMC Industrial Chemicals) located in the United States [33].
Secondly, the concentration of propellant-grade hydrogen peroxide was so much higher than that
commonly used in the laboratory that there were no suitable existing storage facilities at MIT, nor any
personnel trained to receive and handle the chemical. Again, there is a good deal of literature available
describing protocols for safe storage of highly concentrated hydrogen peroxide (see, e.g., [30] and [34]),
and several companies that sell propellant-grade hydrogen peroxide or related components also offer
training sessions or other consulting services which the TALARIS project could utilize [33,35]. However,
this is clearly another area in which considerably more resources would have to be expended to create a
safe and working hydrogen peroxide system than for a cold gas system.
Summary
To summarize, a monopropellant hydrogen peroxide propulsion system would almost certainly have a
higher performance than a cold gas propulsion system of equivalent mass, given the expected
properties of the TALARIS hopper. However, a hydrogen peroxide system would also have more design
constraints and be more complex, though not prohibitively so. Furthermore, there are many more
serious safety issues related to hydrogen peroxide than to cold gas propellants, and a great deal of
preparation and training would be needed to protect personnel. This is an especially large commitment
due to the high turnover of students working on TALARIS; each semester, new students join the project,
while some experienced students graduate or otherwise move on. None of these drawbacks are
insurmountable obstacles on their own. However, when added together, they represent a significantly
greater investment of resources in the development of the TALARIS spacecraft emulator propulsion
system. Time was deemed to be an especially critical resource; given the competitive nature of the
GLXP, the TALARIS vehicle had to demonstrate at least some hopping capability as soon as possible.
Thus, it was decided to continue designing a cold gas propulsion system for the TALARIS hopper.
Development of the TALARIS spacecraft emulator propulsion system could thus proceed more rapidly,
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