ERPS Site:
Experimental Rocket Propulsion Society
What's New The SF Bay Area's Non-profit Liquid-Fuel Rocket Engine Team


& Goals
Board &
Meetings Getting
& Video

In the beginning...

The E.R.P.S. was founded in February of 1993 to gather interested amateurs in a group that would learn about, design, build, and test liquid fuel rocket engines. Its founders, Michael Wallis and Kevin Bollinger, hoped to foster and disseminate "nuts and bolts" knowledge of rocket science, and thereby speed the day when truly routine access to space would be achieved.

Early on, the group decided to concentrate on developing and testing high density, room-temperature-storable propellant combinations. The reason was because they allowed the maximum amount of work to be done with the minimum amount of risk to life, limb and logistics. After research and consultations, high-purity Hydrogen Peroxide (H2O2) was selected as the oxidizer of choice, with the intent to use it with a high-density kerosene such as JP5 or regular Jet-A. In the meantime, the H2O2 (also known as HTP, or "high-test peroxide") could serve as a monopropellant, permitting the group to "cut its teeth" on relatively safe rockets with reasonable performance.

Over the next eleven years, the group acquired access to rocket-engine assembly and test facilities and, more important, active members with the skills to make good use of those facilities. We've achieved a number of successes — notably, the first repeated amateur launch of the same vehicle within one 24-hour period.

Where we're headed ...

The group was founded to pursue the development of technology capable of reaching Low Earth Orbit (LEO) in a single stage. That goal has not changed, even though it's taking longer to get there than we expected. The keys to this achievement are lots of building and testing.

Since beginning with HTP in mono-propellant vehicles made logistical sense, best performance demanded concentrations of 95% and higher. Therefore the E.R.P.S. set out to find, by research, test and experimentation, a catalyst formulation that could operate with 95% to 100% peroxide without deteriorating. Such a catalyst would be of great value in the efforts to open the space frontier. We believe we have such a catalyst, but we need to run more tests to make sure. We expect to complete those tests later this year.

Getting to the next level of performance (and, ultimately, LEO) will require a bi-propellant vehicle — which adds a whole new order of complexity.

Vehicle control is another challenge. We have a team working on control issues. Their primary tool at present is a home-brew propellor-driven testbed called "Gizmocopter". The idea is that control software can be developed on Gizmo, with testing done locally, and later transferred relatively quickly to a multi-engine rocket vehicle. This team is also responsible for the electronics on our existing rockets.

Our other challenges include logistics (keeping track of parts, tools, etc.), documentation (too often overlooked, but essential to a successful development effort), safety, and regulatory affairs.

To sum up, we are designing and building a series of increasingly capable vehicles, the last of which will reach low Earth orbit. If you're interested in helping us reach that goal, read through the Web site to find out what we've doing in more detail. Then show up at a general meeting and volunteer for a job where you think you can make a contribution.

Board and Officers

The ERPS is directed by a board chosen from the executive membership. Director elections are held in August of each year, at the annual meeting, with nominations commencing the previous May. Officer elections are also held at the annual meeting.

The current slate of officers is:

Members of the Board of Directors for the current year are:


It's long been an ERPS tradition to meet over dinner. For our general meetings, the meeting room in a restaurant works best. Many of us are on tight budgets, so we tend to prefer inexpensive restaurants; our choices have included Harry's Hofbrau, IHOP, and CoCo's. However, we don't tolerate inferior food or service. Currently, we meet at the Denny's on Bowers Avenue in Santa Clara. Meetings are held on the first and third Thursdays of every month, holidays permitting. The meetings begin at 8 PM; if you want dinner, it's wise to get there at 7.

The address of the Denny's is 3399 Bowers Avenue, Santa Clara 95054. That's just south of U.S. 101; Bowers crosses 101 and becomes Great America Parkway on the other side. If you're coming from 101, the Denny's will be on your left. Here are some links to maps of the location:

The location as mapped by Yahoo's server.

MapQuest's map.

Joining ERPS

There are three classes of membership in ERPS: Observer, Participating, and Executive.

We provide a printable ERPS Membership Application Form on-line. Simply fill in the requested information, print a copy, and mail it to the address indicated. (If you live nearby, you can bring it to a meeting.)

E-mail List

The membership of ERPS is worldwide. These far-flung members keep in touch chiefly by participating in the Society's electronic mailing list. Instructions for signing up, as well as an archive of past messages, are found here.

Contact Information

Because of the voluntary nature of the group, there is no ERPS office, no full-time (or even part-time) staff to answer questions in real time. (We do maintain a post office box: PO Box 61642, Sunnyvale, CA 94088-1642.)

The Internet lets us maintain contact among members, keep track of progress, notify people in the local area of meetings, and receive valuable help from more distant contributors. The main avenue for this communication is the ERPS e-mail list. Instructions for subscribing to the list and archives of past posts are available on the list info page.

Regular meetings are held the first and third Thursdays 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 e-mail list or on the Web site.

News Archive

The news archive is still under construction. Please be patient.

Pictures & Videos

We have amassed a large collection of still images and videos documenting our rocket assembly and test activities. The best of these are accessible through the following links:

Videos of Rocket Assembly & Testing

Still pictures of ERPS activities

Copyright 2004 E.R.P.S.

Last Updated: 21:04:34 on 01 Apr 04

Site design by Michael Wallis and Chris Winter

Web services provided by: Wallis International Networking Services