China's Space Program Thread II

[taxiya]

The big deal with Zhuque 2 is it's the first rocket powered by methane to reach orbit. It all comes down to being more "environmental friendly" and ease of production. What the actual savings in costs are I don't know. I would guess methane is cheaper. Other companies using kerosene is likely they don't have the expertise and just use what they can afford.

Some advantages to methane:

1. Simpler And Cheaper To Produce
2. Little To No Coking And Other Forms Of Residue Buildup
3. Environmentally Friendly
4. Higher Specific Impulse Than RP-1 (Kerosene)
5. Can Be Produced On Other Celestial Bodies
6. Smaller Fuel Tanks Required Compared To Hydrogen
7. No Additional Compounds Needed To Keep Fuel Tanks Pressurized
8. Allows Rocket Engines To Run At Higher Pressures

AFAIK, methane is better than kerosene:

1. Methane engines can produce more specific impulse than kerosene. This means more delta-v for the mass of fuel and engine.
2. Methane takes up much less volume than other fuels like hydrogen, so the tanks can be smaller and lighter. It can be chilled before launch, causing it to shrink even further.
3. Methane is much cleaner burning than kerosene, eliminating problems with carbon deposits causing dangerous hot spots and blockages and greatly reducing the need for overhaul before reuse.
4. Methane can be made anywhere in space that power and common raw materials are available—including the surface of Mars.
5. Methane is plentiful and cheap in the form of natural gas (at least on Earth).
6. The boiling point of oxygen and methane are close enough you can easily prevent one freezing the other with a little insulation. That’s not the case with hydrogen (which will freeze oxygen) or kerosene (which will be frozen by it). These problems can be addressed with other fuels, but at the cost of extra weight.

Besides naturally easier to handel re-usability than Kerosene (air blown inside) and maybe cheaper to produce, other advantages are all quationable to non-existent.

Specific impulse (by volume) is slightly better than Kerocene but specific impulse (by mass) is much LOWER, meaning worse performance than Kerocene as first stage. In high altitude, it is far worse than LOX/LH2, only slightly better than Kerocene.

Methane is the WORST green house gas in big volume. At launch, it will be leaked on purpose to relieve the tank pressure caused by heat from the sun. I don't think it is any batter than the pollutents from Kerocene.

Producing Methane on other planet will remain a science fiction for 100 years and more if EVER. It is pointless to refer it as an advantage.

Bigger fuel tank than Kerocene and SRB. We should not cherry-pick.

Higher combustion chamber pressure is NOT the advantage of Methane fuel, BUT "Full Flow Cycle" which can be used by LOX/LH2 engine as well.

These subjects have been repeatedly discussed in the thread, I would appreciate that we don't go back to the basics.

 

[taxiya]

So a methane-fueled engine is more relevant as it goes up the rocket stages just as a hydrogen-fueled engine becomes the choice for the 2nd/3rd stage of the rocket.

Yes

A combination of kerosene, methane, and hydrogen-fuelled rocket could be the most efficient yet.

If you talk about pure performance in terms of payload capability, there is no place for methane.

There are two types of impulses, by volume and by mass. At sea level when the rocket goes vertically you want high impulse by mass, so the best first stage is SRB. At high altitude when the rocket goes side ways, you want high impulse by volume, so the best is LOX/LH2.

Kerocene having higher impulse by mass than methane is a better choice for 1st stage than methane. Methane 2nd stage is better than Kerocene but if one choose performace, one would choose LOX/LH2 anyway. So Methane has no place in the performance focused rocket. It is "高不成，低不就".

Methane is however a good compromise if one build a rocket with all methane stages for a lower cost. That is what Starship is doing.

 

[taxiya]

OK someone explain to me why this Landspace Zhuque 2 is such a big deal? Is it just because methane is a very cheap fuel? How much of the cost of an orbital flight is the fuel?

Honestly, it is a big deal mostly because it beats SpaceX. It would not have been a thing if it was not because SpaceX fans bloating methane/raptor as some kind magic.

Also I see some Chinese private space companies are going with kerosene - is that as cheap or otherwise better than methane?

both have pros and cons as I said in the other post.

 

[ZachL111]

Will be good to see how these private conmpanies will faire, especially if they prove to be even more efficient/effective than the state owned ones. Wil be intersting to see if they will be able to compete fairly with state owned launch companies this coming decade and how this competition might help the industry. Hopefully they will be given the chance to compete fairly and win contracts if they can provide a better service.
Funny enough it actually seems to me that the first chinese space company to launch a reusable rocket in Space will be a provate company instead of a state. Before i thought the long march 8 resuable version will be launch soon, but since there has been no real information or news about that since then, i actualy think private chinese rocket launch company have a better chance and timeline they have given are more viable. Interesting times ahead for Chinas space industry

I'm just in awe at how fast the private space industry in China has caught up to the private space industry in the West, despite only really being launched in 2014. Especially with the booming private space VC funding I have seen over the past three years, along with the innovative approach combining both public/private ventures with purely private ventures, to explore many areas at once, I honestly see China overtaking our space industry in the next few decades.

 

[Red tsunami]

Translation:
Figure 1: High definition rendering of CSST optical facility structure v1.1
Figure 2: Schematic diagram of CSST main optical system
Figure 4: Schematic diagram of CSST inside CZ-5B fairing
Figure 6: Overall Structure Model of CSST Sky Survey Module
Figure 7-9: Main technical parameters of CSST optical facilities (main optical machine+various back-end modules) v1.1

CSST is expected to be launched no earlier than the end of 2024, and is likely to be postponed to 2025.

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[Red tsunami]

 

[taxiya]

CSST is expected to be launched no earlier than the end of 2024, and is likely to be postponed to 2025.

This kind of "internet fans making up plans" really bugs me. The only official statement from CAS (who makes and owns CSST) is 预计于2024年前后投入科学运行", from a 2021 publication on their web site here

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It means "CSST will be operational in a time span before to after 2024", that means 2023, 2024 and 2025. Then some internet fans decided that CAS promised operational in 2024, therefor launch in 2023. So CAS delayed it to launch in 2024, then delayed again to 2025. The exact same thing happened to WS-15. The reality is that these fans either can't read Chinese, or have no access to facts but spewing out all sorts of "bragging, blaming, complaining".

 

[Michael90]

I'm just in awe at how fast the private space industry in China has caught up to the private space industry in the West, despite only really being launched in 2014. Especially with the booming private space VC funding I have seen over the past three years, along with the innovative approach combining both public/private ventures with purely private ventures, to explore many areas at once, I honestly see China overtaking our space industry in the next few decades.

Yeah i agree. Unfortunately it seems again that due to various reasons most often private enterprises usually perform better than state owned ones if given the dale opportunities/level playing field . The only thing thay remains to be seen is if private space companies will not make state owned ones uncomfortable with increasing competition. So we will have to see if they wil be given the same opportunity/level playing field to compete with SOE or if they will be restricted and limited to just a particular sector in the industry to protect state owned ones who currently have a quasi monopoly for many decades now. Afterall, nobody likes others taking their business. So guess the crucial player here will have to be the Chinese government intervening to ensure there is fair competition.

 

[FairAndUnbiased]

Yeah i agree. Unfortunately it seems again that due to various reasons most often private enterprises usually perform better than state owned ones if given the dale opportunities/level playing field . The only thing thay remains to be seen is if private space companies will not make state owned ones uncomfortable with increasing competition. So we will have to see if they wil be given the same opportunity/level playing field to compete with SOE or if they will be restricted and limited to just a particular sector in the industry to protect state owned ones who currently have a quasi monopoly for many decades now. Afterall, nobody likes others taking their business. So guess the crucial player here will have to be the Chinese government intervening to ensure there is fair competition.

The state owned companies still own the infrastructure to build parts, build satellites, provide services (fuel, telemetry),and a monopoly on solid fuel. They have their military and CNSA business. They also have emergency satellite launch TELs like the Kuaizhou-1, as well as build missiles. They'll be fine.

I think the whole point of this is to transition SOEs out of the commercial launch sector and have them be more military and scientific oriented, as well as a being a supplier. Getting the PLA and MIC out of civilian business has been very important to the CMC since the 1990s.

 

[56860]