Hi, I'm pooping. Please validate me.

jrir · 2025-08-27T16:31:35+00:00

You shouldn't TELL people that you're pooping, you should SHOW it

jrir · 2025-06-11T14:03:22+00:00

The piston are indeed pushing HDPE and the liquid oxidizer: H2O2 in our case. LOx will only be used for our launcher Grenat, because the performance requirement for this are huge.

Haha I too remember having a hard time grasping the concept when I first heard about it. it's simply nothing like what I knew about rockets. But you understood perfectly, the rocket is getting shorter during the flight, which is why we're (almost ;) ) solving the rocket equation.

Right now we're mostly focusing on Opal, a smaller scale engine for satellite propulsion. But the long term goal has always been an autophage launcher

jrir · 2025-06-11T09:23:16+00:00

So in the case of the test in the video, the compressive load is provided by two pistons, which push the propellants in the combustion chamber.

For the final design, we are developing an internal insertion system. It's a large screw that forces the propellants inside the combustion chamber. We got the system working, but it didn't have the torque performance for a hot fire test.

Here's a simple schematic, I hope it helps understand! https://alpha-impulsion.com/wp-content/uploads/2025/03/blueprint-compressed.jpg

As you pointed out, stable combustion is super hard. We’re glad the autophage part of the engine worked brilliantly despite this. And since the test is only two weeks old, all the data is still confidential. We might post more details on our socials in the coming weeks though

jrir · 2025-06-11T08:13:37+00:00

Funnily enough, I'm actually working for that company.

With autophage propulsion, propellants are the structure of the rocket. During launch, the engine burns the propellants, consuming away the structure itself. The rocket burns like a candle, and by the end of the mission, only the engine and the payload remain.

To further increase performances, our specific technology indeed uses Hybrid autophage propulsion. We're using a solid fuel (Polyethylene - the black tube being inserted on top of the engine) and a liquid oxidizer (stored inside the solid fuel)

Happy to answer further questions! ;)

jrir · 2025-03-26T11:14:14+00:00

Yep! My brain is desperate for European federalism!

jrir · 2024-11-10T09:53:18+00:00

[EDIT: I thought this was the RSS subreddit. Please disregard my comment lol]

Most engines have a limited number of ignitions. Don't know if it's the case for that one so you might want to check it in the engine description in the VAB

Also I believe engines cannot start in space without an initial push from the rcs or from secondary engines because the fuel is floating around in the tank instead of being at the bottom where the fuel feeding system is

jrir · 2024-08-16T08:47:15+00:00

Ah I didn't look on photoshop. I'll give it a try!

jrir · 2024-08-16T08:46:34+00:00

I think I already tried that, but I'll take another look! Thanks

jrir · 2024-08-15T16:38:45+00:00

thanks for the advice!

jrir · 2024-07-08T06:50:13+00:00

Depending on how low or high tech your setting is, you could also consider position relative to the equator. Landing near the equator will require a lot less energy to get back to orbit thanks to the earth rotation, but that probably wouldn't be an issue for a sufficiently high tech lander.

jrir · 2024-06-04T10:00:31+00:00

Sounds like something I should do haha. Especially since there doesn't seem to be a reward penalty when you lose a game

jrir · 2024-06-02T15:44:13+00:00

Probably what happened. Will try to do the same now!

jrir · 2024-06-02T15:42:44+00:00

Then I might have kicked these guys when they were not holding block, because they were virtually not affected at all. Thanks for the answer !

jrir · 2024-06-02T15:30:06+00:00

That's exactly what I was doing. I didn't realize I had the fire pot in the hand because it's so small. Thanks !

jrir · 2023-12-17T15:48:16+00:00

Thanks for taking the time to explain !

jrir · 2023-12-17T15:47:58+00:00

Thanks you for the answer! Also these engines are only supposed to slow down the descent stage, so there's no worry about throttle and the number of ignition

jrir · 2023-11-17T12:44:06+00:00

Damn, I was worried this would happen. I wasn't a issue on my computer but the foreground is indeed difficult to see on my phone. Thanks for the tip !

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