In the beginning …
The E.R.P.S. was founded in February of 1993 to gather together interested amateurs to learn about, design, build, and test liquid fuel rocket engines. The group early on decided to concentrate on developing and testing high density storable propellant combinations because they allowed the maximum amount of work to be done with the minimum amount of risk to life and limb. After research and consultations, high density Hydrogen Peroxide (H2O2) was selected as the oxidizer of choice, with the intent to combine it with a high-density kerosene such as JP5 or regular Jet-A.
HTP by any other name …
Peroxide, when catalyzed, produces steam (2 H2O) and pure oxygen (O2) at high temperatures. Peroxide makes a fair mono-propellant when used in concentrations above 95% and there was historical experience (the British ‘Black Knight’ program of the late 60’s and early 70’s) to show that respectable performances and capabilities could be developed even at lower concentration when combined with a high density liquid hydrocarbon. The British, however, limited themselves by the catalyst they chose to work with, silver screens. Because the melting point of silver is low (at 936.93o C), using peroxide at concentrations above about 85% generates a heat of reaction high enough to melt the silver and thereby reduce and eventually eliminate the “catalyst” from the reaction. The physical properties of the reaction and the type of catalyst used, therefore, limited their performance.
Where we’re headed …
We decided to pursue the development of technology capable of reaching Low Earth Orbit (LEO) in a single stage. It was decided that the performance of 95% and higher concentrations was required, and therefore the E.R.P.S. set out to find, by research, test and experimentation, catalyst the could operate with 95% to 100% pure peroxide without deteriorating. Such a catalyst would be of great value in the efforts to open the space frontier.
The Basics
E.R.P.S. is a volunteer, non-profit liquid fuel rocket engine design and test group based in the San Jose area of Northern California. We’re experimenting with and developing new rocket engines using high density propellents that are storable at room temperature and that will allow us to demonstrate simplicity of operation and cost advantages for single-stage-to-orbit launch vehicles. (My that sounds very long winded!) There are some areas of research that are proprietary and there are some that are not posted for liability issues (school kids playing with high strength oxidizers without proper adult supervision is a personal nightmare of mine). Outside of those areas, E.R.P.S. has all along wanted to be a central source for information and safety procedures for high density propellents. While the main web site isn’t as up to date as I’d like, we’ve recently started this blog page will be working on building both a better record of the ongoing research and on putting together the safety and training pages we’ve long wanted to provide.
High Test Peroxide
The basics of what we’ve been doing is developing new catalysts for use with high strength hydrogen peroxide (HTP). The current catalyst under test looks to work at up to 98% H2O2 without deterioration, but we’re in the process of building new facilities for producing HTP in quantity to use for testing and in getting commercial manufacturing of the catalyst started to allow for ease of assembly.When peroxide passes over a catalyst it breaks down into water and pure oxygen in the formula:
It also expands from a liquid to a gas at about 600:1 ratio. As a mono propellent, H2O2 develops a reasonable thrust by channelling the expansion gases out a standard Bell nozzle.
Gas “jets” of peroxide have been used in space on board things like the Mercury capsule and the NF-104 exo-atmospheric aircraft (flown by Chuck Yeager and depicted in the movie “The Right Stuff”, for example). Because the process generates a lot of heat, the choice of catalyst is important. Most H2O2 rockets have used silver screens, which limit them to 85% concentrations because the heat generated becomes higher than the melting point of silver, thereby removing your catalyst and rendering your engine useless.
The British did a lot of work with HTP engine development in the late 50’s and into the 60’s, including actually launching a satellite into polar orbit from Woomera, Australia using a multi-stage Peroxide/Kerosene vehicle. Check out the Black Knight and Black Arrow programs for additional details on their use of silver screen catalysts. In typical British fashion, however, the program was cancelled and everyone went back to the UK. 8-(
Development Plans
At 98% concentrations we generate about 1800o F, which is absorbed by the oxygen (the water heats to 212oF and becomes steam). For higher performance, we plan to add high density kerosene to the flow (when added to a pure oxygen flow at 1800o any hydrocarbon fuel will ignite) and basically double the performance of the engines. These bi-propellent engines should provide enough thrust at low weight to make single stage reusable vehicles feasible.
Aside from the static engine testing, we’ve developed some rudimentary flight test tools (GIZMOs) and platforms (POGOs) to assist with the coding of the Flight Control System. These are mostly very simple platforms for conducting tests of the RCS thrusters (Reaction Control System) to keep the platform stable in the air and for differential throttling of groups of engines for main propulsion stability in “hover” and “landing” modes. Initial hardware is starting to come together for these systems now. We’ve also flown liquid fueled ballistic vehicle with traditional parachute recovery systems (which usually worked), to demonstrate basic performance of peroxide mono-propellent engines.
Down the road, we’re looking at extending the flight characteristics with a larger, more sophisticated vehicle called ReSOAR. This will be used to extend the flight regime in incremental steps to verify the scalability and robustness of the design and code. ReSOAR will test the aerospike engine concept in flight for the first time. It will also be the first vehicle to test aerospike/airflow interactions at Max Q (the point of highest dynamic pressure), rocket engine restart in the atmosphere, base-first powered reentry and reusable sounding rocket operations and cost efficiency.
Following on the lessons learned during ReSOAR flights will be PROTO, a Private Rocket To Orbit Tiny Objects, the first true single stage reusable launch vehicle with orbital capabilities. While its’ payload will likely be only 20 lbs or so to a nominal 150 nautical mile high orbit, PROTO will demonstrate the feasibility of reusable SSTO vehicles and provide a cost-effective platform for launching micro satellites for university research programs and commercial applications.
Contact Information
Because of the volunteer nature of the E.R.P.S., there isn’t really any mailing address or “office” where people can answer questions in real time. By using the Internet, we are able to maintain contact, keep track of progress, notify people in the local area of meetings, and receive valuable input from more distant contributors. The main avenue for this communication is the E.R.P.S. email list. Instructions for subscribing to the list and archives ofpast posts are available on the list info page.
Regular meetings are held the third Tuesday of the month in Sunnyvale, California. If you’re local (or visiting) and would like to attend a meeting, watch for the “Next Meeting …” notices in the list or on the web page.