News on China's scientific and technological development.

tphuang said:

Posting this here, since I find the idea of an all CFRP rocket body to be just as relevant in material science as space. They apparently use some special resin that is cryogenic resistant, liquid O2-compatible mixed together with your carbon fiber to be usable for in space environment and with the Liquid O2/methane fuel. It also uses advanced continuous fiber 3D Printing for key parts in the rocket. Again, 3D Printing specialized parts in rocket engines is really taking off. In fact, advanced material science + 3d Printing seem to be the catch phrase for rocket launchers and aerospace engines in China these days.

Click to expand...

CFRP is always a mess with cryogenic fuel. I would not even bother. Also, composites are way more expensive than aluminium. In infrastruture terms you need expensive tools like autoclaves. It just not worth it.

gelgoog said:

CFRP is always a mess with cryogenic fuel. I would not even bother. Also, composites are way more expensive than aluminium. In infrastruture terms you need expensive tools like autoclaves. It just not worth it.

Click to expand...

It did mention they are cryo-resistant, something to do with the resin I guess. I'm more interested in the material life time for multiple reuses, if they perform as well as aluminum alloys then it is very worthwhile, 30% weight saving.

I remember one of NASA's old proposal for SSTO (was it venture star?) involves a fully carbon fiber lifting body design with LH2/O2 fuel. They abandoned it due to the difficulty with carbon fiber fuel tank.

Also I wonder how do they do with respect to re-entry heating. Weight saving is a lot more critical for upper stage, especially for re-usable upper stage like starship. If carbon fiber can be used in this way it would be huge.

In the Venture Star even the supposedly easy LOX fuel tank never worked properly. Let alone that LH2 multi-lobed monstrosity. I meant just look at those fuel tanks.



With the Venture Star it was not just the composite fuel tanks which were a problem. It turned out the aerospike engine was much heavier than originally expected. The whole vehicle had the center of mass much further behind than expected. Which is a problem in a winged spacecraft.

gelgoog said:

In the Venture Star even the supposedly easy LOX fuel tank never worked properly. Let alone that LH2 multi-lobed monstrosity.

Click to expand...

Yeah well tech is always evolving. Hopefully the Chinese company did crack it for real. And they're working with methane/Lox, much easier than LH2

With the Venture Star it was not just the composites fuel tanks which were a problem. It turned out the aerospike engine was much heavier than originally expected. The whole vehicle had the center of mass much further behind than expected. Which is a problem in a winged spacecraft.

Click to expand...

I ran into the exact same issue replicating it in KSP, I ended up just enlarging the tail fins to compensate lol

In the Venture Star it is like they tried making everything as hard as possible to make the whole thing fail. A lot of people think this was accepted by NASA just to discredit the DC-X which originally came from the BMDO. NASA NIH syndrome.

gelgoog said:

In the Venture Star it is like they tried making everything as hard as possible to make the whole thing fail. A lot of people think this was accepted by NASA just to discredit the DC-X which originally came from the BMDO. NASA NIH syndrome.

Click to expand...

Well in hindsight SSTO was never going to work in the place place, not without some magical propulsion or magical material. But enough with venture star we're off topic. Anyway I'm pretty bullish on carbon fiber, hope the company make it