The U.S. government defines deep space as anything beyond low-earth orbit. [1] Others vary. [2] The U.S. "Deep Space Network" was created because communications with low-earth orbit and beyond-LEO had very different requirements [3].
Deep space should be the furthest point reached by probes in likeness to deep ocean depth exploration. Voyager I, II and New Horizon probes should redefine the ”distance.“
Fascinating. I was just a kid in 1964 when I learned about fluidics. My December issue of Scientific American had an article on fluidics featured on the cover and I always wondered why there never seemed to be any applications of the devices described in that article. In particular, the use of fluidic logic gates and latches, etc.
Not sure the relationship, but they say 600PSI chamber pressure, or about 20 bar. Spacex is push 200 to 300 bar pressures. I would think this means they're currently at a low ISP. The challenge with RDEs has been keeping them lit, I e. Keeping the detonation wave going indefinitely. Once that's done they can work of efficiency. Seems like they're at that point now.
Pressure can tell you about thrust, but I don't think its as strongly linked to specific impulse. However looking at the wiki article on the RS25 which is pretty high up there being a hydrolox engine, I see it's also got a chamber pressure in the 200+ bar range.
This was a smaller prototype. Unless they release a theoretical Isp model for scaling up the engine (which, would we believe them if they did?) we can't know for certain yet.
Up to 25% improvement compared to conventional rocket engines according to the Wikipedia page. I haven’t found an actual ISP measurement for this NASA engine, though.
It seems that 25% paragraph on wikipedia cites a non-technical article[1] from 2018:
"Theoretical calculations have shown that detonation combustion is 25% more efficient than the isobaric combustion cycle, which corresponds to constant-pressure combustion, which is implemented in the chambers of of modern liquid propulsion engines."
From another article[2] of the same year:
"Conservatively speaking, a rotating detonation combustor, or RDC, should reduce specific fuel consumption by about 5% compared to a conventional engine. This measure of fuel efficiency is calculated by dividing fuel consumption by power output. A rotating detonation engine generates more power, which drives down specific fuel consumption. A reduction on the order of 5 percent would be a breakthrough, given that designers of conventional engines “try to eke out fractions of a percent,” says Scott Claflin, director of advanced concepts at the Rocket Shop, Aerojet Rocketdyne’s innovation organization."
> that 25% paragraph on wikipedia cites a non-technical article[1] from 2018
The article you footnoted is also in Cyrillic.
After all this time, it's amazing to see people trust Wikipedia. It's like they don't care if it's true or not; it's entertainment, pretending to know, not knowledge.
A perfect way to spin your wheels forever and go nowhere.
It’s a big deal because “the tyranny of the rocket equation” works in reverse too. Just as adding fuel is a compounding problem, reducing fuel is a compounding benefit.
Looking at the size of the rocket that went to the moon vs the size of the rocket that came back from the moon says it all. It seems completely unrealistic to colonize the solar system from earth.
The only way is to set up industries on the moon to build the ships and equipment necessary to expand through the solar system.
Simulations aren't really the limiter on engine efficiency, SpaceX etc already lean heavily on simulations.
The limiters on engine efficiency at this point are mostly materials and costs, and even the latter are coming down with better fuels (eg Methane, which is extremely popular with rockets debuting this decade) and different design philosophies (eg SpaceX's Raptor engine, which is supposedly under $1M per engine while being the most advanced flight tested rocket engine out there).
There is never going to be a 100% improvement in 'normal' rockets - you cant gey any more energu out of a chemical reacrion. We are using all the energy that we can get out of the most powerfull fuels that exist.
The only two ways to get 'sci-fi style rocket is either nuclear, or to beam energy to the rocket from outside with giant lasers.
Agree that 25% doesn't sound very exciting or revolutionary, but computers have been used to design space-related stuff for a while, for example, https://www.jpl.nasa.gov/nmp/st5/TECHNOLOGY/antenna.html . I would be surprised if no one had tried it with propulsion systems yet.
From 10% to 35% is a 25% improvement, you're still at 35%... From 70 to 95% is a 25% improvement, but it's a lot more. Going from 98 to 99% is only 1% but also like really a 10x improvment.
Rockets are operating at pretty decent efficiency, 25% improvment on an internal combusion engine would be mind blowing and make EVs way less interetsting.
There are theoretical maximum efficencies for various types of engines due to thermodynamics. You always lose energy to heat. Entropy is a b**.
yes but people often conflate/confuse that... saying the delta in %'s... not % improvement. I agree with you, I'm attempting to point out how a small % increase is a huge actual improvement. This GP was saying that a 25% improvment in the efficiency of a rocket engine was not much to a layman.
What's up with all of these crazy technical developments after a period of relative stagnation?
Aside from it being merely random or selection bias, it's plausible that there's some kind of AI assist beyond what we know happening behind the scenes.
These baseless speculations about ChatGPT are somewhat ironic given that the article itself alludes to what has unlocked this specific advance:
"The RDRE achieved its primary test objective by demonstrating that its hardware – made from novel additive manufacturing, or 3D printing, designs and processes – could operate for long durations while withstanding the extreme heat and pressure environments generated by detonations."
It's much easier to imagine that steady advances in manufacturing, computational modeling, and "mundane" technologies like that are contributing to progress like what's described in this article... Rather than some super secret AI assistant.
Please, folks, don't give up on reading just because computers can do it too now. :)
People have been working on rotating detonation engines, and making steady progress, for years. The idea dates to the '60s, but i think work really picked up about a decade ago.
OH MY.... Came here to say "Wow, this is so much more exciting than the 123th LLM/GPT and the 2746th "this is my experience / use case with AI" (sorry) "but sure, some one will come and claim that: GPT-8 would have designed that alone given the right prompt!!"
...
and then need to read this. :(
I said a few days ago that it is very likely 3 letter agencies and other organisations have had GPT4 equivalent models for some time now. It doesn’t seem that unlikely that some branches of the US gov would have much more advanced models.
Why do people always say this? It's almost like a thought-terminating cliche. Thousands of companies competing with each other were not able to do it earlier, but the NSA always has better everything, by definition.
Maybe ChatGPT is helping cut through bureaucratic tape. I know it’s helped me become much more persuasive in my communication. If your goal is to convince the US government to spend money testing your rotational detonation engine, your odds of success go up if an LLM helps you write the email.
