Image of detonation engine firing

Japanese Rocket Engine Explodes: Continuously And On Purpose

Liquid-fuelled rocket engine design has largely followed a simple template since the development of the German V-2 rocket in the middle of World War 2. Propellant and oxidizer are mixed in a combustion chamber, creating a mixture of hot gases at high pressure that very much wish to leave out the back of the rocket, generating thrust.

However, the Japan Aerospace Exploration Agency (JAXA) has recently completed a successful test of a different type of rocket, known as a rotating detonation engine. The engine relies on an entirely different method of combustion, with the aim to produce more thrust from less fuel. We’ll dive into how it works, and how the Japanese test bodes for the future of this technology.

Deflagration vs. Detonation

Humans love combusting fuels in order to do useful work. Thus far in our history, whether we look at steam engines, gasoline engines, or even rocket engines, all these technologies have had one thing in common: they all rely on fuel that burns in a deflagration. It’s the easily controlled manner of slow combustion that we’re all familiar with since we started sitting around campfires. Continue reading “Japanese Rocket Engine Explodes: Continuously And On Purpose”

3D Printing Steel Parts At Home Via Special Filaments

Rocket engines are great for producing thrust from fire and fury, but they’re also difficult to make. They require high-strength materials that can withstand the high temperatures involved. [Integza], however, has tried for a long time to 3D print himself a working rocket engine. His latest attempt involves printing an aerospike design out of metal.

Even steel couldn’t hold up to the fury of the rocket exhaust!

The project relies on special metal-impregnated 3D printer filaments. The part can be printed with a regular 3D printer and then fired to leave just the metal behind. The filament can be harsh, so [Integza] uses a ruby nozzle to handle the metal-impregnated material. Processing the material requires a medium-temperature “debinding” stage in a kiln which removes the plastic, before a high-temperature sintering process that bonds the remaining metal particles into a hopefully-contiguous whole. The process worked well for bronze, though was a little trickier for steel.

Armed with a steel aerospike rocket nozzle, [Integza] attempts using the parts with his 3D printed rocket fuel we’ve seen before. The configuration does generate some thrust, and lasts longer than most of [Integza]’s previous efforts, though still succumbs to the intense heat of the rocket exhaust.

Overall, though, it’s a great example of what it takes to print steel parts at home. You’ll need a quality 3D printer, ruby nozzles and a controllable kiln, but it can be done. If you manage to print something awesome, be sure to drop us a line. Video after the break.

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A High Power Wood Rocket In 5 Days

Getting started with model rocketry is relatively cheap and easy, but as you move up in high power rocketry, there are a few hoops to jump through. To be able to buy rocket motors larger than H (160 N·s / 36 lbf·s impulse) in the US, you need to get certified by the National Association of Rocketry. The main requirement of this certification involves building, flying, and recovering a rocket with the specific motor class required for the certification level. [Xyla Foxlin] had committed to doing her Level 2 certification with a couple of friends, thanks to the old procrastination monster, was forced to build a rocket with only 5 days remaining to launch data.

For Level 2 certification, the rocket needs to fly with a J motor, which is capable of producing more than 640 N·s of impulse. Fortunately [Xyla] had already designed the rocket in OpenRocket, and ordered the motor and major body, nosecone, and parachute components. The body was built around 2 sections of 3″ cardboard tubes, which are covered in a few layers of fiberglass. The stabilizing fins were laser cut from cheap plywood and were epoxied to the inner tube which holds the motor and passes through the sides of the outer tube. The fins are also fibreglassed to increased strength. For a unique touch, she covered the rocket with a real wood veneer, with the rocket’s name, [Fifi], inlaid with darker wood. The recovery system is a basic parachute, connected to the rocket body with Kevlar rope.

[Xyla] finished her rocket just in time for the trek out to the rocket range. She successfully did the certification flight and recovered [Fifi] in reusable condition, which is a requirement. There was nothing groundbreaking about [Fifi], but then again, reliability the main requirement. You don’t want to do a certification with a fancy experimental rocket that could easily fail. Continue reading “A High Power Wood Rocket In 5 Days”

FreeCAD Takes Off With A Rocket Design Workbench

Here’s how FreeCAD works: the program’s design space is separated into different “workbenches”, each of which is intended for a particular set of operations, and a piece of work can be moved between them as needed. There is a sketching workbench, a part design workbench, and now a Rocket workbench has been added to the healthy ecosystem of FreeCAD add-ons. There’s even a series of video tutorials; ain’t open source grand?

It all started when [concretedog] posted on the FreeCAD forums, making a strong case for a Rocket-themed workbench. People got interested, and a short while later [DavesRocketShop] had some useful tools up and running. Here’s a blog post by [concretedog] which goes into detail and background, and while the Rocket workbench is available via FreeCAD’s add-on manager, the very latest experimental builds are available for manual installation on [Dave]’s GitHub repository.

This sort of development and utility is exactly the kind of thing our own Elliot Williams was describing when he made the point that one of open source’s greatest strengths is in the little things, like the FreeCAD ecosystem letting people scratch strange and specific itches, and the ability to share those solutions with others.

Experimenting With 3D Printed Rocket Nozzles

Rocketry is an exacting science, involving a wide variety of disciplines, encompassing everything from fluid mechanics to thermodynamics and materials engineering. As complex as it sounds, that doesn’t mean it’s beyond the purview of the average maker. [Sciencish] demonstrates this with a series of experiments on rocket nozzles in the home lab. (Video, embedded below.)

The video starts with an amusing analogy about nozzle design based on people fleeing a bad pizza. From there, [Sciencish] 3D prints a wide variety of nozzle designs for testing. The traditional bell nozzle is there, of course, along with the familiar toroidal and linear aerospikes and an expansion deflection design. Of course, 3D printing makes it easy to try out fun, oddball geometries, so there’s also a cowbell nozzle , along with the fancy looking square and triangular aerospikes too. Testing involves running the nozzles on a test stand instrumented with a load cell. A soda bottle is filled with rubbing alcohol vapour, and the mixture is ignited, with each nozzle graded on its thrust output. The rockets are later flown outside, reaching heights over 40 feet.

[Sciencish] notes that the results are a rough guide only, as the fuel/air mixture was poorly controlled. Despite this, it’s a great look at nozzle design and all the science involved. It also wouldn’t be too hard to introduce a little more rigour and get more accurate data, either. However, if solid fuels are more your jam, consider brewing up some rocket candy instead.

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Crossed Wires Crash Rockets

On November 17th, a Vega rocket lifted off from French Guiana with its payload of two Earth observation satellites. The booster, coincidentally the 17th Vega to fly, performed perfectly: the solid-propellant rocket engines that make up its first three stages burned in succession. But soon after the fourth stage of the Vega ignited its liquid-fueled RD-843 engine, it became clear that something was very wrong. While telemetry showed the engine was operating as expected, the vehicle’s trajectory and acceleration started to deviate from the expected values.

There was no dramatic moment that would have indicated to the casual observer that the booster had failed. But by the time the mission clock had hit twelve minutes, there was no denying that the vehicle wasn’t going to make its intended orbit. While the live stream hosts continued extolling the virtues of the Vega rocket and the scientific payloads it carried, the screens behind them showed that the mission was doomed.

Displays behind the hosts clearly showed Vega wasn’t following the planned trajectory.

Unfortunately, there’s little room for error when it comes to spaceflight. Despite reaching a peak altitude of roughly 250 kilometers (155 miles), the Vega’s Attitude Vernier Upper Module (AVUM) failed to maintain the velocity and heading necessary to achieve orbit. Eventually the AVUM and the two satellites it carried came crashing back down to Earth, reportedly impacting an uninhabited area not far from where the third stage was expected to fall.

Although we’ve gotten a lot better at it, getting to space remains exceptionally difficult. It’s an inescapable reality that rockets will occasionally fail and their payloads will be lost. Yet the fact that Vega has had two failures in as many years is somewhat troubling, especially since the booster has only flown 17 missions so far. A success rate of 88% isn’t terrible, but it’s certainly on the lower end of the spectrum. For comparison, boosters such as the Soyuz, Falcon 9, and Atlas have success rates of 95% or higher.

Further failures could erode customer trust in the relatively new rocket, which has only been flying since 2012 and is facing stiff competition from commercial launch providers. If Vega is to become the European workhorse that operator Arianespace hopes, figuring out what went wrong on this launch and making sure it never happens again is of the utmost importance.

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A Farewell To Hackaday’s Favorite Falcon 9 Booster

With the notable exception of the Space Shuttle, rockets and spacecraft have always been considered disposable. It’s a slow and expensive way to travel, akin to building a new airliner for every flight, but it was the easiest option. These vehicles have always represented the pinnacle of engineering and material science of their time, and just surviving the trip to space once was an incredible accomplishment. To have another go around would have been asking too much of the technology. Even looking back on the Space Shuttle program, there’s plenty of debate about whether or not the reusable design really paid off in the end.

So SpaceX’s ability to land, refurbish, and refly the first stage of their Falcon 9 booster is no small accomplishment. After demonstrating the idea was possible in 2017, the company made numerous changes to the latest iteration of the rocket with reusability in mind. Known as Block 5, this version of the Falcon 9 is designed to be more survivable and require minimal servicing between flights. The company says its cheaper and faster to reuse the Block 5 than it would be to build a new one for each flight, allowing the company to approach spaceflight more like commercial aviation.

Falcon 9 launch and landing streaks
Falcon 9 launch and landing streaks. (Source: SpaceX)

With a fleet of Block 5 boosters now in rotation, SpaceX has given them serial numbers not unlike an airplane’s tail number. It might not be the kind of thing the general public would normally be aware of, but these serial numbers have allowed a dedicated community of space aficionados to keep track of the missions each booster has flown.

Unfortunately the story of one of these rockets, officially referred to as “Cores” in SpaceX parlance, was recently cut short. Core B1056, returning from the Starlink 4 mission on February 17th, failed to land on the autonomous spaceport drone ship (ASDS) Of Course I Still Love You and splashed down in the ocean. It’s still unclear what condition the booster was in after its soft landing in the water, but when the recovery ships returned to port empty handed, there was no question as to the fate of B1056.

From a purely business standpoint, the failure of any of SpaceX’s boosters means lost time and revenue. But in some ways B1056 had established itself as the vanguard of the fleet, managing to either set or break a number of records in its relatively short life. The destruction of the most thoroughly flight proven Block 5 booster is a stark reminder that there’s very little about spaceflight that could be called routine.

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