from the future-deep-space-exploration dept.
Japan successfully tests rocket engine propelled by new technology
Japan on Tuesday successfully tested a rocket engine that was propelled by new technology using shock waves produced by burning a mixture of methane and oxygen gases, with the aim of applying the propulsion method to deep space exploration in the future, the country’s space agency said.
The No. 31 vehicle of the S-520 sounding rocket series, measuring 8 meters in length and 52 centimeters in diameter and carrying the engine, lifted off from the Uchinoura Space Center in Kagoshima Prefecture at around 5:30 a.m., according to the Japan Aerospace Exploration Agency.
It reached an altitude of 235 kilometers four minutes and four seconds after the launch and landed in the sea southeast of Uchinoura about eight minutes later, with JAXA retrieving a capsule containing test data in nearby waters.
[...] Jiro Kasahara, a Nagoya University professor, jointly developing the technology with JAXA, said the test demonstrated that the engine maintained a propelling force in space as expected.
“We will aim to put the technology into practical use in about five years,” he said.
InterestingEngineering offers some numbers
The rocket began the tests after the first stage separated, firing the rotating detonation engine for six seconds. When the rocket was recovered from the ocean after the demonstration, it was discovered that the rotating detonation engine produced around 500 Newtons of thrust.
More info:
A rotating detonation engine (RDE) is a proposed engine using a form of pressure gain combustion, where one or more detonations continuously travel around an annular channel. Computational simulations and experimental results have shown that the RDE has potential in transport and other applications.
In detonative combustion, the results expand at supersonic speed. It is theoretically more efficient than conventional deflagrative combustion by as much as 25%. Such an efficiency gain would provide major fuel savings.
Disadvantages include instability and noise.
May 2020, UCF Researchers Develop Groundbreaking New Rocket-Propulsion System
A University of Central Florida researcher and his team have developed an advanced new rocket-propulsion system once thought to be impossible.
The system, known as a rotating detonation rocket engine, will allow upper stage rockets for space missions to become lighter, travel farther, and burn more cleanly.
The results were published this month in the journal Combustion and Flame.
“The study presents, for the first time, experimental evidence of a safe and functioning hydrogen and oxygen propellant detonation in a rotating detonation rocket engine,”...
Feb 2021, Successful engine test brings Australian space launch capability a step closer (also covered by S/N). Not too much information of fuel/oxidant, thrust or frequency of operations for this one.
Related Stories
Successful engine test brings Australian space launch capability a step closer:
An Australian research consortium has successfully tested a next generation propulsion system that could enable high-speed flight and space launch services.
The team's rotating detonation engine, or RDE, is a major technical achievement and an Australian first.
It was designed by RMIT University engineers and is being developed by a consortium led by DefendTex, with researchers from RMIT, University of Sydney and Universität der Bundeswehr in Germany.
How it works
While conventional rocket engines operate by burning fuel at constant pressure, RDEs produce thrust by rapidly detonating their propellant in a ring-shaped combustor. Once started, the engine is in a self-sustaining cycle of detonation waves that travel around the combustor at supersonic speeds greater than 2.5km a second.
Using this type of combustion has the potential to significantly increase engine efficiency and performance, with applications in rocket propulsion and high-speed airbreathing engines—similar to ramjets.
Benefits over existing engines include better fuel efficiency, simpler flight systems and a more compact engine, allowing for larger payloads and reduced launch costs.
[...] Although this technology is in its early stages, further development could support satellite launches from Australian soil and commercial opportunities for Australia's space industry, while indirectly supporting telecommunications, agriculture, transport, logistics and other industries.
YouTube video: What Is A Rotating Detonation Engine - And Why Are They Better Than Regular Engines
(Score: 0, Interesting) by Anonymous Coward on Sunday August 22 2021, @04:41AM (16 children)
"the rotating detonation engine produced around 500 Newtons of thrust.
To put that into context, SpaceX's large cargo-lifting rocket Falcon Heavy, for example, has three Falcon 9 nine-engine cores whose 27-Merlin engines together generate more than 5 million pounds of thrust"
Context???
What is that in milihorsepower?
(Score: 3, Informative) by mhajicek on Sunday August 22 2021, @04:50AM (9 children)
500 Newtons = 112.4 pounds force. Must have been a very small test engine. I'd be curious what ISP it got
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 3, Interesting) by Beryllium Sphere (r) on Sunday August 22 2021, @05:47AM
I wonder if it's noteworthy that the design scales down that small.
(Score: 2) by FatPhil on Sunday August 22 2021, @09:57AM (7 children)
Best to just avoid the use of nonsense units entirely.
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2) by mhajicek on Sunday August 22 2021, @02:29PM (6 children)
Don't think so. I work with these units when testing medical device parts. Check it with an online unit converter.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 3, Interesting) by FatPhil on Sunday August 22 2021, @03:12PM (5 children)
Apologies, you're perfectly right.
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2) by mhajicek on Sunday August 22 2021, @06:21PM (3 children)
My gut check was a device I tested to failure at around 800 Newtons, which I recall was in the vicinity of 250 pounds.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 2) by FatPhil on Monday August 23 2021, @07:53AM (2 children)
However, I suspect I'll never need to know the ratio, I have genuinely never encountred the lbf in 50 years of existence.
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2) by FatPhil on Monday August 23 2021, @07:54AM (1 child)
metric masses yield g metric forces' force
far better. or not.
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2) by Immerman on Tuesday August 24 2021, @12:45AM
Can't tell you the aggravation I went through dealing with the fact that the US customary system predominantly measures weight instead of mass. You want to do any calculations? First convert the weight of your object into slugs, since nobody measures slugs. And then something about the relationship of of pound-mass, pound-force, slugs, and slug-force constantly tripped me up.
Metric was much easier - everybody measures mass rather than weight, almost nobody uses obtuse things like kg-force, and g=10m/s is close enough for most applications so that 1kg weighs 10N.
(Score: 2) by mhajicek on Sunday August 22 2021, @06:23PM
Though it seems my memory was off, 800N = 180 pounds force.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 2) by c0lo on Sunday August 22 2021, @06:30AM (5 children)
You don't measure impulse in horsepower.
https://www.youtube.com/@ProfSteveKeen https://soylentnews.org/~MichaelDavidCrawford
(Score: 0) by Anonymous Coward on Sunday August 22 2021, @06:40AM (4 children)
Indeed. Space rockets propel by the principle of the conversation of momentum.
(Score: 0) by Anonymous Coward on Sunday August 22 2021, @06:55AM (3 children)
Uhm.... conservation, not conversation.
Anyway, what I mean, for yous even more ignint than I am, is this.
Cars propel by pushing against the ground. Airplanes propel by pushing against the air/atmosphere. There is neither ground nor air in the space, so the rockets must propel forward by shooting matters backward. Momentum is defined as mass times speed.
(Score: 3, Interesting) by c0lo on Sunday August 22 2021, @07:58AM (2 children)
Airlift is pushing against atmosphere - higher pressure on the down side of the airfoil. Same for propellers, made of airfoils.
But jetplanes are working mostly by conservation of momentum - the air at the exit of the jet has a much lower pressure than the atmospheric one (necessary so, it exits at higher velocity).
https://www.youtube.com/@ProfSteveKeen https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by maxwell demon on Monday August 23 2021, @12:43PM (1 child)
Of course pushing against the atmosphere just means transferring momentum to the atmosphere. And that is what both propellers and jet engines do, just in a different way.
There is no way of propelling other than by conservation of momentum (there are some reaction-less drive concepts, but they depend on non-standard physics, and none has yet been proved to actually work).
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by c0lo on Tuesday August 24 2021, @01:27AM
Ah, the statistical mechanics basis for thermodynamics, where the macroscopic pressure is derived from the impulse transfer of the particles making up a fluid.
Not very useful for practical flight engineering, tho' (not everybody's favourite lifestyle to keep an eye on an Angstrom-sized gate to open it up only for "hotter" particles, but I can understand the fascination for some - friendly grin)
The same way the quantum mechanics is not very useful in practical chemistry - yes, Raman/IR spectra will tell you what compound resulted from the reaction, but it's very seldom that one gets to design the reaction from quantum mechanics considerations.
If you have a fascination for backyard chemistry as a science: from https://www.youtube.com/watch?v=D4vDwQ4TyIc [youtube.com] to https://www.youtube.com/watch?v=PxPjBz_8S3c [youtube.com] with some facinating (to me at least) steps on the way there.
https://www.youtube.com/@ProfSteveKeen https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by Rosco P. Coltrane on Sunday August 22 2021, @06:19AM (11 children)
So they reinvented the pulsejet?
They must have found old V1 blueprints from their German friends...
(Score: 3, Informative) by c0lo on Sunday August 22 2021, @06:34AM (10 children)
Wrong. Pulsejet uses combustion (and at low compression ratios, so it has abysmal efficiency).
This one uses detonation - explosions at super/hypersonic speeds, with pressures like the ones in the shock-wave front. Gets 25% more efficiency than what Musk is using.
https://www.youtube.com/@ProfSteveKeen https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by Rosco P. Coltrane on Sunday August 22 2021, @08:28AM (4 children)
Well quite. No doubt it's a clever version of the old pulsejet idea, complete with beaucoup improvements and amazing engineering to make it work. Possibly, it doesn't bear much resemblance to the original idea.
But tell me: if I don't point out the similarity, how else am I gonna plug a cheap Nazi joke eh? :)
(Score: 2) by c0lo on Sunday August 22 2021, @09:28AM (1 child)
I'm reminded of Shipstone description. That one with "improved storage battery".
Were I to have some time at the moment, I'd take it as a challenge.
https://www.youtube.com/@ProfSteveKeen https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by PinkyGigglebrain on Sunday August 22 2021, @07:07PM
Dear Goddess, I haven't heard anyone mention shipstones in a very long time.
Thank you for that short jaunt down amnesia lane :)
Now I'm really hoping I still have that copy of Friday [wikipedia.org] in storage.
"Beware those who would deny you Knowledge, For in their hearts they dream themselves your Master."
(Score: 3, Informative) by Kell on Sunday August 22 2021, @09:31AM
By making reference to Wernher von Braun, ideally in the form of a song by Tom Lehrer.
Scientists ask questions. Engineers solve problems.
(Score: 3, Informative) by mhajicek on Sunday August 22 2021, @02:32PM
It's not like a pulse jet. This engine has a constant detonation front that orbits inside the combustion chamber, no pulsing.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 5, Informative) by deimtee on Sunday August 22 2021, @08:51AM (2 children)
H2 + O2 rockets can get an Isp of around 400. Bumping that up to 500 would be useful but it's still not as good as the 1200 they were getting with NERVA.
One job constant is that good employers have low turnover, so opportunities to join good employers are relatively rare.
(Score: 2) by c0lo on Sunday August 22 2021, @09:20AM (1 child)
On the flip side, it's much safer.
https://www.youtube.com/@ProfSteveKeen https://soylentnews.org/~MichaelDavidCrawford
(Score: 2) by mhajicek on Sunday August 22 2021, @02:35PM
And smaller, lighter, and likely much cheaper.
The spacelike surfaces of time foliations can have a cusp at the surface of discontinuity. - P. Hajicek
(Score: 0) by Anonymous Coward on Monday August 23 2021, @11:42PM (1 child)
Rotating detonation engines are derived from pulse jets. It goes Pulse jet->Pulse detonation->Rotating detonation. Scott Manley explains it far better than I can. https://www.youtube.com/watch?v=rG_Eh0J_4_s [youtube.com]
(Score: 2) by c0lo on Tuesday August 24 2021, @12:59AM
Almost true
By the same measure, an ICE combusting gasoline is derived from an electric vehicle. You see, those spark plugs are what keeps it firing.
https://www.youtube.com/@ProfSteveKeen https://soylentnews.org/~MichaelDavidCrawford
(Score: 0) by Anonymous Coward on Sunday August 22 2021, @06:23AM
Snow cones for everyone! Muscel cars in space! Nah this is more like rice Berners in space. Green space engines!
Fun close tag..
Space requires energy-efficient travel or you don't get wherever you're going. It's a good thing we can figure this stuff out before we go. Even so, people will die in deep space. The price you pay to be the first.
You first, no you first, no you first.
(Score: 2) by ElizabethGreene on Monday August 23 2021, @02:51PM (1 child)
There are two ways to burn a fuel/oxidizer mix, combustion or detonation.
A traditional rocket engine uses combustion, a process that produces a subsonic flame front. The exhaust gasses then flow through a convergent-divergent nozzle to transition the flow to supersonic.
In a detonation engine, the flamefront is supersonic. The advantage of this is that it increases the exhaust velocity, the #1 metric for how fuel/oxidizer efficient a rocket engine can be.
We've had intermittent detonation engines. pulsejets, for a long time. In a pulsejet the in the fuel in the combustion changer detonates, the chamber refills, and the next detonation occurs. You can hear this in the boom-boom-boom-boom of the rocket's exhaust. Unfortunately in these the engine is detonating only a tiny fraction of the engine cycle time. Most of the time is waiting to refill the engine.
The cool technology they are demonstrating is a continuous rotary detonation engine. Via magic and physics they maintain one or more supersonic flame fronts propagating continuously around an annular combustion chamber in space! AFAIK it's previously only been done in a lab.
Note: I'm unclear if the rotary detonation engine still uses a CD nozzle downstream of the combustion chamber.
(Score: 0) by Anonymous Coward on Monday August 23 2021, @11:49PM
They use a nozzle just like any other chemical rocket. The "EnterestingEngineering" link in the summary has a picture of it. It looks like a toroidal aerospike.