Open Source Liquid Rocket Reaches For The Sky

August 20, 2024 by Tom Nardi 30 Comments

Since the very beginning, solid-propellants have been the cornerstone of amateur rocketry. From the little Estes rocket picked up from the toy store, to vehicles like the University of Southern California’s Traveler IV that (probably) crossed the Kármán line in 2019, a rapidly burning chunk of solid propellant is responsible for pushing them skyward. That’s not to say that amateur rockets powered by liquid propellants are completely unheard of … it’s just that getting them right is so ridiculously difficult that comparatively few have been built.

But thanks to [Half Cat Rocketry], we may start to see more hobbyists and students taking on the challenge. Their Mojave Sphinx liquid-fueled rocket is not only designed to be as easy and cheap to build as possible, but it’s been released as open source so that others can replicate it. All of the 2D and 3D CAD files have been made available under the GPLv3 license, and if you’re in the mood for a little light reading, there’s a nearly 370 page guidebook you can download that covers building and launching the rocket.

Now of course we’re still talking about literal rocket science here, so while we don’t doubt a sufficiently motivated individual could put one of these together on their own, you’ll probably want to gather up a couple friends and have a well-stocked makerspace to operate out of. All told, [Half Cat] estimates you should be able to build a Mojave Sphinx for less than $2,000 USD, but that assumes everything is done in-house and you don’t contract out any of the machining.

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The Amateur Rocketry Hack Chat Reaches For The Stars

December 2, 2022 by Tom Nardi 7 Comments

Hackaday has been around long enough to see incredible changes in what’s possible at the hobbyist level. The tools, techniques, and materials available today border on science-fiction compared to what the average individual had access to even just a decade ago. On a day to day basis, that’s manifested itself as increasingly elaborate electronic projects that in many cases bear little resemblance to the cobbled together gadgets which graced these pages in the early 2000s.

But these gains aren’t limited to our normal niche — hobbyists of all walks have been pushing their respective envelopes. Take for example the successful launch of MESOS, a homebuilt reusable multi-stage rocket, to the very edge of the Kármán line. It was designed and built by amateur rocket enthusiast Kip Daugirdas over the course of several years, and if all goes to plan, will take flight once again this summer with improved hardware that just might help it cross the internationally recognized 100 kilometer boundary that marks the edge of space.

We were fortunate enough to have Kip stop by the Hack Chat this week to talk all things rocketry, and the result was a predictably lively conversation. Many in our community have a fascination with spaceflight, and even though MESOS might not technically have made it that far yet (there’s some debate depending on who’s definition you want to use), it’s certainly close enough to get our imaginations running wild.

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Student-Built Rocket Engine Packs A Punch

October 24, 2019 by Bryan Cockfield 30 Comments

A group of students at Boston University recently made a successful test of a powerful rocket engine intended for 100km suborbital flights. Known as the Iron Lotus (although made out of mild steel rather than iron), this test allowed them to perfect the timing and perfect their engine design (also posted to Reddit) which they hope will eventually make them the first collegiate group to send a rocket to space.

Unlike solid rocket fuel designs, this engine is powered by liquid fuel which comes with a ton of challenges to overcome. It is a pressure-fed engine design which involves a pressurized unreactive gas forcing the propellants, in this case isopropanol and N2O, into the combustion chamber. The team used this design to produce 2,553 lb*ft of thrust during this test, which seems to be enough to make this a class P rocket motor. For scale, the highest class in use by amateurs is class S. Their test used mild steel rather than stainless to keep the costs down, but they plan to use a more durable material in the final product.

The Boston University Rocket Propulsion Group is an interesting student organization to keep an eye on. By any stretch of the imagination they are well on their way to getting their rocket design to fly into space. Be sure to check out their other projects as well, and if you’re into amateur rocketry in general there are a lot of interesting things you can do even with class A motors.

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DIY Falcon Heavy 2nd stage test flight of BPS.space

Rocket Science With The Other SpaceX

September 18, 2018 by Steven Dufresne 29 Comments

When you say that something’s not rocket science you mean that it’s not as hard to understand or do as it may seem. The implication is that rocket science is something which is hard and best left to the likes of SpaceX or NASA. But that’s not the hacker spirit.

[Joe Barnard] recently had an unsuccessful flight of his Falcon Heavy’s second stage and gives a very clear explanation of what went wrong using those two simple concepts along with the thrust, which in this case is just the force applied to the moment arm.

And no, you didn’t miss a big happening with SpaceX. His Falcon Heavy is a homebrew one using model rocket solid boosters. Mind you, it is a little more advanced than that as he’s implemented thrust vectoring by controlling the engine’s direction using servo motors.

And therein lies the problem. The second stage’s inertia is so small and the moment arm so short that even a small misalignment in the thrust vectoring results in a big effect on the moment arm causing the vehicle to deviate from the desired path. You can see this in the first video below. Another issue he discusses is the high drag, but we’ll leave that to the second video below which contains his explanation and some chart analysis.

So yeah, maybe rocket science is rocket science. But there’s no better way to get your feet wet then to get out there and get building.

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Building Homebrew VTOL Rockets

February 16, 2017 by Brian Benchoff 35 Comments

No one can deny what SpaceX and Blue Origin are doing is a feat of technological wizardry. Building a rocket that takes off vertically, goes into space, and lands back on the pad is an astonishing technical achievement that is literally rocket science. However, both SpaceX and Blue Origin have a few things going for them. They have money, first of all. They’re building big rockets, so there’s a nice mass to thrust cube law efficiency bump. They’re using liquid fueled engines that can be throttled.

[Joe Barnard] isn’t working with the same constraints SpaceX and Blue Origin have. He’s still building a rocket that can take off and land vertically, but he’s doing it the hard way. He’s building VTOL model rockets. Most of the parts are 3D printed. And he’s using solid motors you can buy at a hobby shop. This is the hard way of doing things, and [Joe] is seeing some limited success with his designs.

While the rockets coming out of Barnard Propulsion Systems look like models of SpaceX’s test vehicles, there’s a lot more here than looks. [Joe] is using a thrust vectoring system — basically mounting the Estes motor in a gimbal attached to a pair of servos. This allows the rockets to fly straight up without fins or even the launch rod used to get the rocket up to speed in the first few millseconds of flight. This is active stabilization of a model rocket, with the inevitable comments of ITAR violations following soon afterward.

Taking off vertically is one thing, but [Joe] is also trying to land his rockets vertically. Each rocket he’s built has a second Estes motor used only for landing. During descent, the onboard microcontroller calculates the speed, altitude, and determines if it’s safe to attempt a vertical landing. If the second motor has sufficient impulse to make velocity and altitude equal zero at the same time, the landing legs deploy and the rocket hopefully makes a soft touchdown in the grass.

While [Joe] hasn’t quite managed to pull off a vertical takeoff and landing with black powder motors quite yet, he’s documenting and livestreaming all of his attempts. You can check out the latest one from a week ago below.

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Serial Telemetry To Wi-Fi With An ESP8266

March 4, 2016 by Jenny List 12 Comments

Hackaday.io user [J. M. Hopkins] had a problem with his rocketry. Telemetry from the rockets came down to Earth via a 433MHz serial link, but picking just the bits he needed from a sea of data for later analysis on a laptop screen on bright sunny days was getting a little difficult.

His solution was to bring the serial data from his transceiver module to an ESP8266, and from that both share it over WiFi and display pertinent information via I2C to an LCD for easy reference. And he’s put the whole lot with a power supply in a rather splendid wooden case with an SMA socket on the back to attach his Yagi.

All information received from the telemetry is passed to a client connecting via Telnet over the WiFi, but pertinent information for the LCD is selected by sending it from the rocket enclosed in square brackets. We hope that the source code will be forthcoming in time.

This isn’t the first time we’ve featured rocket telemetry here at Hackaday. And we’d be missing a trick if we didn’t point out that this project is using our own Hackaday-branded Huzzah ESP8266 breakout board from the Hackaday Store.

Hacklet 68 – Rocket Projects

July 31, 2015 by Adam Fabio 12 Comments

There’s just something amazing about counting down and watching a rocket lift off the pad, soaring high into the sky. The excitement is multiplied when the rocket is one you built yourself. Amateur rocketry has been inspiring hackers and engineers for centuries. In the USA, modern amateur rocketry gained popularity after Sputnik-1, continuing on through the space race. Much of this history captured in the book Rocket Boys by Homer Hickam, which is well worth a read. This week’s Hacklet is dedicated to some of the best rocketry projects on Hackaday.io!

We start with [Sagar] and Guided Rocket. [Sagar] is building a rocket with a self stabilization system. Many projects use articulated fins for this, and [Sagar] plans to add fins in the future, but he’s starting with an articulated rocket motor. The motor sits inside a gimbal, which allows it to tilt about 10 degrees in any direction. An Arduino is the brain of the system. The Arduino gathers data from a MPU6050 IMU sensor, then determines how to steer the rocket motor. Steering is accomplished with a couple of micro servos connected to the gimbal.

Next up is [Howie], with Homemade rocket engine. [Howie] is cooking some seriously hot stuff on his stove. Rocket candy to be precise, similar to the fuel [Homer Hickam] wrote about in Rocket Boys. This solid fuel is so named because one of the main ingredients is sugar. The other main ingredient is stump remover, or potassium nitrate. Everything is mixed and heated together on a skillet for about 30 minutes, then pushed into rocket engine tubes. It goes without saying that you shouldn’t try this one at home unless you’re really sure of what you’re doing!

Everyone wants to know how high their rocket went. [Vcazan] created AltiRocket to record acceleration and altitude data. AltiRocket also transmits the data to the ground via a radio link. An Arduino Nano keeps things light. A BMP108 barometric sensor captures pressure data, which is easily converted into altitude. Launch forces are captured by a 3 Axis accelerometer. A tiny LiPo battery provides power. The entire system is only 23 grams! [Vcazan] has already flown AltiRocket, collecting data from several flights earlier this summer.

Finally we have [J. M. Hopkins] who is working on a huge project to do just about everything! High Power Experimental Rocket Platform includes designing and building everything from the rocket fuel, to the rocket itself, to a GPS guided parachute recovery system. [J. M. Hopkins] has already accomplished two of his goals, making his own fuel and testing nozzle designs. The electronics package to be included on the rocket is impressive, including a GPS, IMU, barometric, and temperature sensors. Data will be sent back to the ground by a 70cm transceiver. The ground station will use a high gain human-guided yagi tracking antenna with a low noise amplifier to pick up the signal.

If you want more rocketry goodness, check out our brand new rocket project list! Rocket projects move fast, if I missed yours as it streaked by, don’t hesitate to drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!