MTA launch event, 2021-07-17

by Dave Nordling, Reaction Research Society

The UCLA Project Prometheus had reserved the RRS MTA for Saturday, July 17, 2021, for another round of static fire testing of a nitrous oxide hybrid motor on our vertical test stand.  Dave Crisalli was the pyrotechnic operator in charge for that day and recorded the successful static fire.  The footage will be posted on the society Instagram page soon.

This summer semester test would demonstrate UCLA’s student designed and built custom hybrid motor.  Average thrust was around 300 lbf with a maximum value of 349 lbf.  Total impulse recorded was 2044 lbf-sec (in the M-motor range).  UCLA shared a few pictures from the event.

Success on the stand…
…starts with good testing in the lab

This was another great example of a university team success thanks to careful design, lab testing, training, planning and smart, in-the-field engineering.  The RRS is glad to offer our facility and technical advice.  The RRS looks forward to working with UCLA again soon.

For teams seeking to schedule the use the RRS MTA, please contact the RRS president, Osvaldo Tarditti.  Always include a full project description such that the society can accurately evaluate your request.

June 2021 Virtual Meeting

by Keith Yoerg (RRS Secretary)

The latest meeting of the Reaction Research Society took place last Friday, June 11th and had 19 attendees – including a guest presentation from the Clarkson University Rocket Club. We kicked off the meeting saying vitrual hello’s and catching up on personal updates – Dimitri is safely in beautiful Alaska but will be down to visit California and may attend an MTA event if one is hosted.

Screenshot of discussion during the monthly meeting


The group kicked off society business with Dave Nordling telling us about the highlights from recent events at the MTA – including liquid and hybrid rockets from the UCLA rocket teams. More details are available in the post from Dave here.

Dave also re-iterated his desire that the Reaction Research Society host at least 1 event at the MTA every month, and asked whether other members were interested in attending an event on Saturday, June 19. A few members expressed interest – and Osvaldo agreed to prepare a few Alpha rockets for Dave to possibly launch. The weather is forecast to be 111 deg Farenheit in the desert this weekend, so anyone attending will need to bring lots of water, sun protection, and other preparations to beat the heat!


David Nagy, Benjamin Ellis, and Tyler Brooks from the Clarkson University Rocket Club were our guest presenters for this month. The club is brand-new (it became active this year!) and these students are working to turn it into a fixture at the university in northern New York state. They are currently in the process of soliciting faculty support, building a composites lab, and procuring equipment to get the club off the ground

Clarkson University Rocket Club members working on building their high-power fiberglass rocket

David, the president of the team, has some previous rocket experience with both high power and liquid rockets – including a 9.5 kN pintle injector rocket engine. The team is currently building their own fiberglass, high power rocket from scratch which they plan to fly on a commercial, CTI 75mm solid rocket rocket motor. This scratch build is not only helping them build out their workspace to do filament winding and carbon fiber layups – they also intend to fly a 3D printed avionics bay with an avionics board designed from scratch. They hope to use the lessons learned from this project to inform work on future, more complicated projects.

David, Benjamin, and Tyler showing designs for a future planned project – a liquid bi-propellant rocket

The Clarkson University team solicited advice and opinions on their plans for a liquid bi-propellant LOX/Ethanol rocket. The design is currently in its early stages but the specifications are to have 500 lbf thrust, with a fuel-centered pintle injector. They predict that with a 15-second burn time they could build a rocket that would reach an apogee of 35,000 ft. Several RRS members gave their opinions on this design and other challenges involved with starting a fledgling club from scratch. I know many of the members are excited to see what these students will do!


We decided to do a short recap of our recent discussions and presentations from vendors of wireless launch controllers. Dimitri offered to let us use his Cobra system when he returns to California in July, and there was talk of attempting to launch 16 low-power kits at the same time to further test/prove the efficacy and safety of the controllers. RRS members seemed generally impressed with the presentation from Cobra last month, but concern was raised that it’s not a necessary expense. There was a bit of a debate about whether laying and coiling several hundred feet of igniter wire is triple-digit changes the calculation, but Osvaldo has graciously offered to be the cable spooler for any project that requests it.


The Executive Council updated the membership on progress with the permanent bathroom. After a meeting in Downey earlier this month, it was agreed that RRS member Wilbur would build the container in the LA area and then transport it out to concrete pads which will need to be built at the MTA site (along with a septic solution). The first step of this process has been completed – and the RRS has placed a down payment on a 20 foot “high-cube” shipping container to be used for the bathroom. A schematic of the container is shown below.

The current plan is still to build 2 of these 20-foot containers. Water will be supplied by a well and stored in a tank installed on top of the bathroom or a nearby storage container. The bathroom facility is planned to be located southeast of the Dosa building, alongside the existing storage containers.


The next RRS monthly meeting will be held virtually on Friday, July 9th at 7:30 pm pacific time. Current members will receive an invite via e-mail the week of the meeting. Non-members (or members who have not received recent invites) can request an invitation by sending an email to:

MTA launch event, 2021-05-29

by Dave Nordling, Reaction Research Society

The Reaction Research Society held a launch event at the Mojave Test Area mainly to support the UCLA Prometheus team for a static fire test of their high powered hybrid motor. UCLA chose one of the largest nitrous oxide hybrid motor designs, the M1575, made by Contrails Rocketry. Dave Crisalli was the pyrotechnic operator in charge for this event. I was his apprentice for the hybrid static fire.

There were three main activities at this event. The first was the UCLA Rocket Project making their preparations to launch their ethanol and LOX vehicle from the Friends of Amateur Rocketry (FAR) site from the 60-foot rail. FAR is just to the south of the RRS MTA where the UCLA Rocket Project had twice in one day static fired their 750 lbf liquid propellant rocket engine just four weeks earlier on 05-01-2021.

Weather conditions were ideal with winds being nearly still for most of the morning. This makes little difference for the hybrid motor static fire testing at the RRS MTA which was the second project by UCLA. Wind would factor heavily in the flight of the UCLA’s liquid rocket.

The third planned activity for UCLA was a series of model rocket flights from several high school teams mentored by UCLA graduate and undergraduate students. Still winds made for easier recovery of the first rockets launched that day.

UCLA Prometheus team prepares for static fire at the RRS MTA on 5-29-2021
Dave Crisalli gives the MTA safety briefing for the event in the loading area where the model rockets were assembled for flight.
UCLA graduate students conducted the model rocket launches from just west of the large test stand at the MTA

UCLA at the end of each Spring Quarter conducts a launch event where student groups build small rockets with egg payloads using single and dual-stage vehicles with model rocket class motors (G and under). UCLA graduate students and Professor Mitchell Spearrin were leading this event.

It is good experience for beginners and experts alike to build and fly model rockets., The RRS has it’s own such internal program called the Yoerg Challenge which is to motivate all members to build and fly a model rocket kit at least once from the RRS MTA. The RRS is known as an experimental society and not limited to the model rocket code, but we are also fully supportive of all forms of propulsion as long as it is safely conducted and compliant to the regulations set by the state of California.

As the UCLA hybrid rocket team was making their system checks, they discovered a problem in their nitrous filling system and valve commands. During this diagnostic period, some of the RRS members went to the nearby FAR site to see how the UCLA liquid rocket preparations were progressing.

UCLA’s liquid rocket set on the 60-foot rail launcher at FAR. The team preparing the vehicle for erecting, loading then flight.
RRS members from left to right, Bill Inman, Waldo Stakes, John Wells and Manuel Marquez, inspect the UCLA liquid rocket on the 60-foot launcher deployed at the FAR site.
A few last minute fixes and the rocket was made ready.
The liquid rocket sits on the rail before raising it for launch.
UCLA’s rocket is in position getting ready to clear the area for propellant loading and pressurization operations.

Some of the RRS members remained at the FAR site to witness the launch. After two years of design, planning, build and world pandemic, the UCLA team liquid rocket launch was an amazing success. Due to the relatively low winds that day under clear skies, recovery was made just under a mile away. Preliminary data from telemetry confirmed a new university team altitude record of 22,000 feet. It was an amazing sight to witness from the observation bunker at the RRS MTA.

UCLA’s liquid rocket had a perfect launch on 5-29-2021 setting a new altitude record of 22,000 feet by a university team. Photo by Xavier Marshall, RRS.

The UCLA Prometheus team had corrected their initial electrical problem and began the series of procedural checks to familiarize the new members of the hybrid rocket team. Some minor adjustments of the motor mount alignment was necessary before getting into test.

The UCLA Prometheus team makes some adjustments to better align the hybrid motor in the vertical skid mounted to classic I-beam at the RRS MTA.
The nitrous oxide K-bottle sits inverted in the sloped stand to allow the liquid to flow from the port. Some nitrous oxide bottles come with an internal siphon line to avoid having to invert the container. The bottle is also being chilled with ice to keep the oxidizer sufficiently dense and improve performance in hot-fire.
The top bulkhead of the hybrid motor is attached to the load cell for thrust measurement. A pressure transmitter is tapped into the nitrous oxide volume to further gauge performance.
The high-powered hybrid motor by Contrails uses four 1/4-inch fill lines and a single smaller vent line from the same floating injector at the mid-point inside
Dave Crisalli (right) inspects the hybrid motor on the test rails before the firing
UCLA Prometheus team tracks their written procedures as they progress to hot-fire in the old blockhouse.

The hybrid motor firing proceeded without further problems and resulted in a spectacular test meeting expected performance. Continuous thrust levels over 600 lbf were recorded but data analysis is still ongoing.

The hybrid motor at startup.
The UCLA hybrid motor at full thrust. Chamber pressure was over 1000 psia.

The team had a second hybrid motor grain ready for another firing so they proceeded with disassembly and inspection of the parts. The floating injector seals were still in good condition but the graphite nozzle having survived many prior hot fire tests did not survive that day’s test. Although the throat was in good condition, the inlet taper had cracked requiring a replacement the team did not have.

The top half of the floating injector with its internal siphon tube protruding up to near the top bulkhead.
The floating injector being removed from the lower half containing the spent fuel propellant grain.
The floating injector was removed after hot-fire and the dual O-ring seals were inspected. Seals were ok for re-use.
The nozzle assembly did not pass inspection after the first and only hot-fire on 05-29-2021.
The graphite nozzle fractured at the inlet taper from the first and only firing that day.

UCLA Prometheus was pleased with the results from the single firing and will proceed with integrating the motor into their flight vehicle for a launch from FAR on June 19, 2021. The RRS will hold an event at the Mojave Test Area on this same Saturday for member projects and will observe the flight from our northern vantage point.

UCLA avionics team conducted a few tests on the GPS tracking module that will fly on their vehicle in June 2021.

In the last hours of the day, after most of the UCLA liquid and hybrid teams had cleared the area, packaged and carried away their trash, packed their equipment and departed the RRS MTA and FAR sites. The UCLA avionics team remained at the MTA to conduct another series of tests on the GPS tracking system. The society was glad to support this diligence which will help assure success in one of the most important aspects of rocketry which is data acquisition from telemetry. If there is no data, it didn’t happen.

For any group interested in using the RRS MTA for their propulsion related projects, download one of our Standard Record Forms from our RRS.ORG website and submit this request to the RRS president. The society has had a long relationship with UCLA and USC, but we are also supportive to any amateur, professional or academic groups wanting to learn from test.