NASA announces with great fanfare a revolutionary method of propelling rockets.

The RDRE differs from a traditional rocket engine by generating thrust using a supersonic combustion phenomenon known as a detonation. This design produces more power while using less fuel than today’s propulsion systems and has the potential to power both human landers and interplanetary vehicles to deep space destinations, such as the Moon and Mars.

Pulsed repetitive detonation. Hmm. Sounds familiar. I think another dude is working on it right now, or maybe just a few minutes ago. Or a couple centuries ago, which is the same as a few minutes in Elon Standard Time. What was his name? Karl Benz?

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Somewhat more seriously: I was working in an acoustics lab at Penn State in the late ’80s. One of our big projects was a new coal pollution control system, funded by Aerojet General. After the project was finished (with no meaningful results) Aerojet considered reusing the setup to test resonant detonation for rockets, but decided to go elsewhere. So this particular line of research is at least 40 years old.