Aerospike Rocket Engines- You learn something new every day.

So, yesterday I heard that a new startup in Texas was looking to build a launcher for small satellites. The company is named Firefly, and of course, a quick google search found mostly pics of Serenity and Mal Reynolds. But one thing caught my eye, was a reference to aerospike engines, which the company plans to use. That lead to the question, what the hell is an aerospike engine?

You’re familiar with a liquid fueled rocket engine, right? Let’s look  at a typical engine. The is the RS-25, a derivative of the Shuttle Main Engine intended for the future SLS platform.

https://upload.wikimedia.org/wikipedia/commons/b/b1/Shuttle_Main_Engine_Test_Firing.jpg

Pumps mix fuel and oxidizer in a combustion chamber that then flows out the bell. Simple enough.

Aerospike engines kinda turn the bell idea upside down. The flame exhaust goes outside of a wedge, and uses ambient air pressure to shape the plume.

Confused? So was I.

[youtube https://www.youtube.com/watch?v=EWf4iOMSPNc]

In spite of extensive testing and several developmental models, the aerospike has never flown to space. Whether Firefly Systems changes that remains to be seen.

4 thoughts on “Aerospike Rocket Engines- You learn something new every day.”

  1. While the aerospike is kind of cool, it’s kind of ironic that they’re emphasizing the low-cost aspect of it as being important to the X-33 that was eventually canned due to basically infinite cost overruns. I’m still bitter because they should have picked the Douglas design which, not only was actually manufacturable, unique among the X-33 proposals, but which had actually flown scale-model tests.

    That’s when I figured out that NASA was basically useless for developing new hardware.

  2. Ah, the eternal promise of the aerospike!
    For even more fun: back in the mid-90s, someone (Gary Hudson?) tossed out an idea: take a basic round aerospike, mount it on a suitable bearing and whatnot, and cant the combustion chambers so it spins, thereby becoming its own high-pressure propellant pump.
    I still wanna try that one. Might make thrust vectoring a little interesting, though….

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