China's Space Program News Thread


Bltizo

Lieutenant General
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I thought the 921 rocket was replacing the CZ-9 concept?

I'm unsure if it's suggesting that "only" CZ-9 will be developed in the future going forwards, or if he's suggesting that CZ-9 will be developed specifically for the mission of developing a moon base.

It's very possible that 921 ends up being developed for initial manned missions (and potentially iterated into reusable variants for terrestial/orbital launches) while CZ-9 is built for larger scale payloads to build more permanent and larger scale bases on the moon.
 

gelgoog

Captain
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Typically people who propose super-heavy rockets like CZ-9 (China) or Ares V, SLS (US) want to use it either for Mars missions or for expanded lunar bases. But the thing is with refueling in orbit you don't need those kinds of rockets for a lunar base, and for extended Mars missions you can use nuclear powered propulsion or solar-electric propulsion using ion engines with for example argon as a reaction mass.

This is not even a new idea. Chelomei's bureau's plans for a Soviet Mars mission used those kinds of propulsion.
In the US Ernst Stuhlinger proposed a solar-electric Mars mission in 1957.
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You assemble the ship in orbit and then you fly to Mars.

The Soviets did nuclear thermal space propulsion research.
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As did the US with NERVA and Dumbo. In the 1990s the US funded a research study called Project Timberwind which was a nuclear powered rocket which used TRISO nuclear fuel in hydrogen fuel to increase performance even further. The technology is not that dissimilar from the HTR-PM pebble bed nuclear reactor the Chinese are already working on. They predicted a 4x increase in payload with it as a second stage.
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The size of the rocket is less important than a lot of people think. They basically want to redo the technologies the Apollo program discarded. Their rocket is the equivalent of the direct ascent rocket discarded as too costly in the 1960s i.e. the NOVA rocket.
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These rockets are so expensive they would be launched once every couple of years. Plus they are all expendable. It is old tech pushed by Mike Griffin when he was NASA President as Ares V and being followed by the US, Russians, and Chinese. It is a colossal waste of money.
 
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taxiya

Colonel
Registered Member
I respectfully disagree. There are plenty of proposals to do that and more without requiring 20 tons on a single launch.
You could use inflatable habitation modules for example (TransHab).
You could also, you know, dig a hole and make that the base. Or you could simply find a cave in the Moon and inhabit that.
Also with a rocket like the Falcon 9 Heavy you can launch a payload like that to the Moon.
You just need to refuel it in orbit for it to get there.

If you expect to bring everything from Earth the lunar colony program will be a failure just like Roanoke colony in the Americas.
You have to live off the fat of the land. Everything possible should be made of lunar materials.

You should only bring tools, parts, and the bare minimum from Earth.
I think you have not understood what have said in previous posts about the "refueling/multi-launches" approach being not adequate. So I repeat once again, hope this time it can get your attention.

Firstly, inflatable habitation module is used to attach to a rigged structure which is the "20 tons" module I am talking about. You forget that TransHab is to be attached to ISS's rigid structure to replace a module rather than replace the whole structure. Besides, you can not mount your critical equipment to a inflatable. TransHab is never designed for that purpose.

All the "natural cave, dig hole" etc. need powerful tools. That is mass which you can not avoid. The hole on earth can be enough, but not in a vacuum, for that you need materials from earth, that is another mass. The total mass would be much higher than bringing a pre-fabricated module below 20 tons from earth. By proposing this alternative, you are creating new and higher demand of mass.

Your only viable solution to the new demand is multiple launches by "refueling". Let me put this way, you are moving to a new house, instead of moving your big couch, refrigerator, 75 inch TV in a big lorry, you dismantle them in pieces and stuff them one by one into your sedan and move them in tens of time, then try to reassemble them in a empty house where you could not eat and sleep for days. In case of moon surface (as your new home), you can not even breath.

And even more critical is that, the "refueling" tech for moon journey does NOT exist now. But the tech for CZ-9 class is there today. You may get the "refueling" working in LEO in the this decade, then you may get it work in LLO in the next decade. By then the China lunar surface station is already built.

The issue of your proposal is NOT that it won't work ever, it is too far in the future to be available, "远水解不了近渴", water far away can not save a dying man in the desert.

As of why I said "refueling" is not there yet, you can do some self-study of the key challenges and progresses. The detail is too much to be covered in this thread. And to remind you, China is ahead of US in space refueling, so if it is really a better alternative China would have already choose it.
 
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taxiya

Colonel
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I thought the 921 rocket was replacing the CZ-9 concept?
I'm unsure if it's suggesting that "only" CZ-9 will be developed in the future going forwards, or if he's suggesting that CZ-9 will be developed specifically for the mission of developing a moon base.

It's very possible that 921 ends up being developed for initial manned missions (and potentially iterated into reusable variants for terrestial/orbital launches) while CZ-9 is built for larger scale payloads to build more permanent and larger scale bases on the moon.

No, nothing is replacing the other.

921 is the further development of the concept "CZ-5DY", a crew-only carrier rocket. CZ-9 is the cargo counter part in the moon mission.
From day one, China's moon mission consists a crew carrier and a cargo carrier.

The only publication I have seen so far (2019) says that China's moon program will begin with surface survey-> surface preparation -> tooling delivery -> basic surface habitat building -> human landing ->.... In this plan, CZ-9 would be used for material landing before 921 put man on the moon.

This plan is not necessarily the only path that China is thinking of. But if China is not under the pressure of competing with US, it is probably the preferred path. The initial targets of both countries were around 2030.

Some people has suggested that, because Trump moved US' manned landing from 2028ish to 2024, earlier 921 landing a man on the moon is preferable. It is essentially a move for bragging right, flag raising act without materialistic benefit. This is only some armatures' wish, not backed by any publication.
 
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by78

Brigadier
Chang-E 5's sampling device, responsible for gathering lunar soil.


 

gelgoog

Captain
Registered Member
I think you have not understood what have said in previous posts about the "refueling/multi-launches" approach being not adequate. So I repeat once again, hope this time it can get your attention.

Firstly, inflatable habitation module is used to attach to a rigged structure which is the "20 tons" module I am talking about. You forget that TransHab is to be attached to ISS's rigid structure to replace a module rather than replace the whole structure. Besides, you can not mount your critical equipment to a inflatable. TransHab is never designed for that purpose.

All the "natural cave, dig hole" etc. need powerful tools. That is mass which you can not avoid. The hole on earth can be enough, but not in a vacuum, for that you need materials from earth, that is another mass. The total mass would be much higher than bringing a pre-fabricated module below 20 tons from earth. By proposing this alternative, you are creating new and higher demand of mass.

Your only viable solution to the new demand is multiple launches by "refueling". Let me put this way, you are moving to a new house, instead of moving your big couch, refrigerator, 75 inch TV in a big lorry, you dismantle them in pieces and stuff them one by one into your sedan and move them in tens of time, then try to reassemble them in a empty house where you could not eat and sleep for days. In case of moon surface (as your new home), you can not even breath.

And even more critical is that, the "refueling" tech for moon journey does NOT exist now. But the tech for CZ-9 class is there today. You may get the "refueling" working in LEO in the this decade, then you may get it work in LLO in the next decade. By then the China lunar surface station is already built.

The issue of your proposal is NOT that it won't work ever, it is too far in the future to be available, "远水解不了近渴", water far away can not save a dying man in the desert.

As of why I said "refueling" is not there yet, you can do some self-study of the key challenges and progresses. The detail is too much to be covered in this thread. And to remind you, China is ahead of US in space refueling, so if it is really a better alternative China would have already choose it.

No, TransHab is a technology. It was originally proposed for Moon and Mars bases.


Later when the ISS was conceived it was proposed as a space station module for it.
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The technology is proven and in orbit attached to the ISS as a subscale demonstrator.
Larger inflatable units have been made on Earth but not flown.

With regards to the technology for in-orbit refueling "not existing" as an argument to make a single launch architecture, you are using the same argument NOVA rocket proponents used which lost against Saturn V as used in Apollo.

For one, it is bogus, how do you think the ISS gets resupplied with water? Not all of it is recycled. Also, the Progress modules can refuel the ISS so the station can reboost itself periodically (either Progress or the ISS can reboost). So pumping liquids isn't a problem.
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It hasn't been tested with cryogenic fuels but there is no reason why this shouldn't work either. Especially with mild cryogenics like liquid oxygen and liquid methane. Even if you want to use liquid hydrogen the problem isn't insurmountable. Lockheed Martin proposed in-orbit refueling of LH2 a couple years back.

Back when the Apollo program was happening, the big bear was in space docking. It was considered dangerous by the proponents of the NOVA rocket. In the end they did tests with the Agena Target Vehicle until they got it right on Earth orbit. With space docking technology proven, which took less then than the time to build SLS now, they could use rendezvous like on Apollo which reduced the launch mass significantly.
 
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