China's Space Program News Thread
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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, 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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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.
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.
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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SinoSoldier
Colonel
So, if I can get this straight...
The 921 rocket is essentially a "CZ-5 Heavy", an offshoot project meant to fast-track CLEP's manned lunar missions, and in many ways comparable to the crewed SLS Block 1. Its design consisting of 3 CZ-5 cores heavily suggests that it's meant to use as much off-the-shelf technology as possible. We can expect this launch vehicle to debut sooner than 2030 which is when the CZ-9 is expected to fly, consistent with photos that the core structures are already in testing.
The CZ-9 is more of a long-term venture designed to haul heavy cargo to lunar orbit and beyond and will not be man-rated. I expect this project to be more on the backburner, with the 921 project stealing the spotlight (and with that most of their engineering talent). In other words, it's the CNSA equivalent of the SLS Block 2 and will likely fly in the same time frame (or maybe later since delays seem to be inevitable with the Chinese space program).
Sounds about right?
So far the Chinese seem to be emulating the SLS program down to a tee.
They were simply emulating the SLS white elephant yes. Now they are emulating SpaceX Falcon Heavy.
The 921 rocket stages will have the same diameter as CZ-5. This likely means they can use much of the same tooling, like circular welding machines, and the same transport infrastructure of the stages from the factory to the launch site. It will use the same engines. They basically have to redesign the tank structures. Because the Chinese engines are more powerful and efficient than the ones on Falcon Heavy they can use seven engines instead of nine engines per stage. In order for it to be reusable like a SpaceX rocket they will have to redesign the engines to have deeper throttling so it won't be as easy to do as an expendable. But it's not like it is impossible.
The 921 rocket stages will have the same diameter as CZ-5. This likely means they can use much of the same tooling, like circular welding machines, and the same transport infrastructure of the stages from the factory to the launch site. It will use the same engines. They basically have to redesign the tank structures. Because the Chinese engines are more powerful and efficient than the ones on Falcon Heavy they can use seven engines instead of nine engines per stage. In order for it to be reusable like a SpaceX rocket they will have to redesign the engines to have deeper throttling so it won't be as easy to do as an expendable. But it's not like it is impossible.
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