Is that a 25% improvement in ISP/exhaust velocity or another metric?

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."

[1] https://rg.ru/2018/01/18/levochkin-vozmozhnost-sozdaniia-det...

[2] https://aerospaceamerica.aiaa.org/departments/increasing-eng...

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.

> The article you footnoted is also in Cyrillic.

And your comment is in Latin, going by your terminology. In the age of decent online translators, do you care to elaborate on why that’s a problem?

I mean, Russia has a fairly large space program, is that surprising?

25% sounds super disappointing from a laymans perspective and not very "revolutionary" in the grand scheme of time and space.

Can't wait until AI will be able to iterate advanced engineering designs in simulation space at incredible speed.

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**.

Technically, from 10% of something to 35% of something is a 350% improvement or a 25 percent point improvement.

https://en.wikipedia.org/wiki/Percentage_point

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.

Actually, from 10% of something to 35% of something is a 250% improvement. You already had the first 10%.

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).

This is the most HN-circa-2023 comment of all time

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.

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.

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.

Other ways are:

1. air launch, which boils down to using the O2 in the air rather than carrying it with you

2. mass driver, which needs to be in a vacuum

3. gravity slingshots

But, yeah, we need a fusion drive.

>2. mass driver, which needs to be in a vacuum

Project HARP[0] disagrees. Launched a payload 110 miles (177km) into space using a 120 foot (36m) long cannon. This was in the 1960s.

[0] https://en.wikipedia.org/wiki/Project_HARP

It didn't achieve orbit.