What Is the Future of Model Rockets in the “New Space” Era?
An Interview with Joe Barnard
The success of SpaceX, and the pending arrival of Blue Origin, has totally disrupted the heavy launcher market, and right alongside that disruption a fierce war is being fought amongst the new entrants with smaller launchers for the the growing small satellite and cubesat market, with the first of the new companies now having reached orbit.
However in contrast to that rapid pace of development in orbital launchers, the “hobby” rocketry scene has been far more static. In an age when you can put an open source cubesat into orbit, or build your own ground station for a few hundred dollars, where now for model rocketry?
So I guess it was just a matter of time before someone in the model rocketry space decided to try and replicate the successes of SpaceX. Which is where Joe Barnard, and his company Barnard Propulsion Systems, comes in.
We’ve looked at Barnard’s Signal board, a thrust vectoring system for model rockets similar to that used by real full-sized rockets, in the past. But with Barnard pushing forward with his plans for propulsive landings, and a building scale model of the Falcon Heavy, we thought we should sit down to talk with the man himself, Joe Barnard.
Can you tell me how you got into model rocketry? Do you have an aerospace background?
I have no background in aerospace, but my dad does! He worked on guidance, navigation, and control (GNC) for several US missile systems and got me started with model rocketry when I was a kid. I had a continued interest in engineering, participating in a few different student competitions through high school. That said, I studied audio production at the Berklee College of Music, so I have no formal training in aerospace or rocketry.
A year or two after graduating college, I took notice of SpaceX and the “new space” phenomenon and got totally hooked. I initially wanted a job at SpaceX, but I couldn’t afford to go back to school. At this point, I was a full time videographer(weddings, music videos, etc), so I bought a few aero/astro textbooks and spent all my free time trying teach myself as best I could.
As for the model rocketry part of that, I figured I couldn’t just show up to SpaceX (or any other aero company) claiming I knew what I was doing — I had to prove it to them. I decided that in order to get my foot in the door without a degree, I had to build a model Falcon 9 rocket that could launch and land, just like the real thing, and send them a video of it. To be clear, building a model rocket that does this is not nearly as complicated as a space launch vehicle. But building a robust guidance computer, flight software, thrust vector control system, etc at such a small scale is where the challenge lies.
Is this your day job? Or is it a ‘side gig’ for you?
It is now! For a long time, BPS.space was a side project while my day job was as a videographer in Boston, MA. About a year and a half ago, I decided to transition the project into an actual business, and I’ve recently been able to go full time with it.
A really important part here is the tremendous generosity of the folks who’ve been following BPS as it grows. We have a Patreon with a few rewards, and none of development or testing would be possible without their support.
Why did you decide to sell the board, rather than just talk about it?
After flights started getting more successful, I got a few requests for a thrust vector control (TVC) kit for model rockets using what I had built. I dismissed these requests initially because turning something like that into a user-friendly experience is difficult, and I wasn’t sure it could be done.
TVC is extremely complicated to get right, even if it doesn’t seem like it at first glance. As the project progressed, the flight computer, mechanics, etc got easier and easier to build, purely through iteration on their designs. Eventually, I gave the kit idea a second look and realised that if it were done correctly, it might be a fun addition to the model rocketry hobby.
What got you interested in thrust vectoring?
A while back, I took a look at several hobby markets and where success for companies was found within them. I ended up finding a sort of Venn diagram that existed with most. One circle represents models that are super detailed, but can’t do much. Think of a fancy model car that sits on someone’s office desk; that kind of thing.
The other circle represents models that function just like their real counterparts. For example in the model aircraft community, there are folks who just go for speed records. They’ll build something that can scream through the air with little ducted fans as fast as possible, but of course these don’t resemble most real aircraft, they’re not built for looks.
Where these circles meet, you end up with models that look and work like the real thing, and that’s what everyone wants. The overwhelming majority of these communities are interested in form + function in what they buy. Model rocketry isn’t there right now — every rocket with fins has to launch and fly like a dart. They lift off the pad and are out of sight in a second. Almost every space launch vehicle starts verrrrry slowly off the launch pad. Famously the Saturn V took 7 seconds to travel one full vehicle length off the launch pad! I want model rockets to look and work like the real thing — A Falcon 9 or Atlas V model that can slowly ascend, and TVC is the only way to achieve that.
Tell me about the Signal?
Signal Alpha was our first attempt at a commercial thrust vectoring kit for model rockets. It was released in a short run in the fall of 2017.
The Signal Alpha kit included a thrust vectoring motor mount, assembly guides, and, of course, the Signal Alpha flight computer. Alpha was programmable via a configuration file on the micro SD card. While it works just fine, it wasn’t the friendliest user interface which is where Signal R2 comes in.
With software upgrades, a bluetooth chip, and a whole new set of sensors, Signal R2 is the latest in the Signal family of flight computers. Once again the kit comes with the thrust vectoring hardware, assembly instructions, and the flight computer. The biggest change for R2 is the addition of the Signal app for iOS and Android devices. The app lets users monitor the state of their rocket, looking at sensor readings, flight settings, etc — mission control for your phone!
Where are you going after the Signal R2?
Not everyone is interested in thrust vector control, and while it’s fun to anticipate and work towards modelling technologies like thrust vector control and propulsive landing in the model rocketry community, Signal R2 is still an experimental kit for advanced rocketeers.
The next step is called Arc! Arc is a small flight computer for any type of model rocket. Arc logs a wide range of flight data, controls parachutes, and is built to be dead simple to use. Piggybacking on the app development work for Signal R2, rocketeers can use Arc to monitor their rocket’s condition on the pad with their phone. Traditional altimeters use confusing button and beeping combinations as a user interface, leaving plenty of room for user error. An intuitive interface on a nearly universal platform, like a smartphone, is the way to fix this.
Tell me about the Falcon Heavy Build?
When Elon Musk states that building the SpaceX Falcon Heavy was harder than they thought it’d be, that applies at the model scale as well.
The BPS Falcon Heavy (FH) model uses four separate flight computers, one for each major stage. Three bottom cores and one second stage are all separately controlled by their own flight computer. For longer burn times, inter-core communication will need to be added, but it’s not necessary for shorter flights. With each computer logging 31 points of data(orientation, altitude, etc) at 40Hz, the whole Falcon Heavy is a data logging monster, recording nearly 5000 vehicle measurements per second!
Each core of the vehicle has thrust vector control, and when all three are attached, the vehicle has roll control too! The side cores passively separate from the center core by dropping away when they burn out. That said, the side cores have spaces for separation motors for flights where inter-core clearance at separation is crucial.
The second stage is quite small but also uses thrust vectoring! It has not flown yet, and I’m confident I can get it working, but this will be extremely tricky to get right. With a massive fairing on top of the second stage just like the real thing, the vehicle will be naturally unstable, and the thrust vector control system will have to work very hard to keep it on course. And to answer the most important question here, yes, there will definitely be a Hot Wheels roadster inside the fairing.
More than anything, FH is a technology demonstrator. FH is meant to push the boundaries of what can be done at the model scale, regardless of if it’s useful, practical, or sensible. Perhaps one day it can be a kit, but setting the vehicle up for flight takes a full day or two of work right now, so one step at a time!
You’re now attempting a real powered landing, how’s it going?
Yep, really well! Right now landing tests are being conducted with a rocket called Echo. It’s a test bed for this type of thing using an internal developer version of the the Signal flight computer. Landing is performed with a signal solid rocket motor which cannot be throttled. While this may not seem possible, a solid motor can get extremely close to landing properly, given that the flight is planned around the impulse available. This means that the Signal computer does a bit of math onboard while monitoring descent speed, orientation, etc. The computer calls the shots here and decides when exactly to hit the brakes and burn the landing motor.
Testing for this is still pretty early on, but things are looking promising. BPS has conducted two recent drop-tests where the rocket is lifted into the air via a UAV, dropped, and given the task of “landing” at a target altitude. It’s a little safer right now to do air landings with a parachute final descent just in case something goes wrong and Signal misses the target.
The first few drop tests were performed over the last year, none of the tests attempted any landings, but they were meant to safely test the landing software, get real descent data, and look at the passive stability of the falling rocket. In early August, we had the first landing test. The vehicle had a landing target of 14m AGL(above ground level) but missed that quite a lot, “landing” instead at 30m AGL. The second test was performed in late August. The vehicle had a landing target of 18m AGL and landed at 20m AGL. Not too bad! For next steps, the GNC software needs a few updates, then it might be time for a ground landing test! Eventually of course, we’ll put the up and down part together and have a model rocket fully capable of launching and propulsively landing.
It’s worth noting here, that like the Falcon Heavy, the point of this isn’t that it’s useful or practical, it’s that propulsive landing is super hard to do, and awesome when it works! I can’t afford to build the big rockets, so I’ll just make the small ones as realistic as I can.
Once you succeed, where then?
Bigger rockets! My hope is that a propulsive landing model will help generate more support for the project and business which directly helps fund larger vehicles.
There are several more solid plans than “bigger rockets” after propulsive landing, but most involve a bit of boring business strategy, and bigger rockets are always more fun. For instance, we’ve been chatting with a few liquid engine manufacturers for work on much larger(still suborbital) vehicles.
You have an joint initiative with universities?
Sure! There has been some interest from several universities in using Signal R2 as a education tool in aero/astro classes. Generally it’s been for use in control theory or embedded systems classes, but I think there’s room to get creative with a few other options.
I feel pretty strongly about this being a great teaching tool. As mentioned, I’m all self-taught with rocketry and aerospace. Through all this experimentation, I’ve received offers from most of the American orbital launch companies. Had I not spent the last few years actually *building* rockets, even just advanced models, I never would have learned with the textbooks alone. Hands-on education is so important for the next generation of scientists, engineers, and astronauts, and it’s tools like Signal that help folks stay inspired and engaged even when these complicated topics can be a bit dry.
How is your work being supported? Do you have partners on the project?
First, again is the support from the folks on Patreon. This all would have ended long ago without them. The journey to bigger and more ambitious projects will involve their support as well. Just want to acknowledge their generosity.
The other support is from companies like Aerotech. They build rocket motors for all sizes of rockets — small, large, and really really large. After hearing my NARCON keynote this winter, they volunteered tremendous time and effort to develop long burning model rocket motors, perfectly suited for thrust vector control and the Signal R2 kit. Most model rocket motors burn for 2–4 seconds, but Aerotech put in all the R&D to push the envelope up to 15–20 seconds! Plenty of time for those realistic launches at the model scale.
A big thanks to Joe Barnard for taking the time to answer our questions, and if you want to learn more about Barnard Propulsion and the Signal, the Signal R2 board has a full user manual online and a ‘build along’ video series. Unlike the original Signal Alpha, which was restricted to residents and citizens of the United States due to ITAR restrictions, the Barnard’s new Signal R2 is an EAR99 item and is now shipping internationally — costing $349.