China's Space Program News Thread


SinoSoldier

Colonel
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.

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.
 

gelgoog

Captain
Registered Member
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.
 

SinoSoldier

Colonel
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.

I meant the SLS in terms of overall lunar mission architecture and phasing. Obviously the Chinese engineers are thinking hard about incorporating SpaceX-esque technologies like reusability and recycling in future blocks of their LVs.

I am almost certain we will not see any reusable variants of the 921 or CZ-9 in either CLEP missions or their initial variants, but it does seem that the projects have been future-proofed so as to incorporate these capabilities in the far future. Maybe that's why they axed plans to build the CZ-9 with solid rocket boosters.

It's also worthy to mention that, even though the 921 rocket does use the same engines found on the CZ-5, a 7-engine cluster will still be quite different from the CZ-5 configuration and thus it'll be difficult to consider this a mere variant of the CZ-5.
 

by78

Brigadier
LandSpace conducts tests on combined(?) TQ-11 and TQ-12 engines.


 

taxiya

Colonel
Registered Member
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.
What you have been saying was interesting. It has led me to study some of your arguments.

However CZ-9 became official in 2019 (see one of my earlier posts), and repeated by CNSA a week ago. From this moment on, forgive me but I have to say that your arguing for or promoting alternatives is irrelevant as far as this thread is concerned.

To be clear, I don't reject your ideas out right, at some point of time in the future they may become better solution for their application scenario. But I will not continue with them until their need arise.
 

taxiya

Colonel
Registered Member
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.
I guess by offshoot and fast-track you meant alternative. And your understanding is a two step approach, first 921 multiple launches to put man on the moon, followed by larger scale landing using CZ-9. My answer is, maybe or maybe not. So far I have not seen any paper suggesting this is the case.

Here is some background information.

In a paper by Long Lehao (2010), there was two phases to land man on the moon. Phase one is multiple launches without CZ-9. Phase two is crew rocket plus CZ-9. In one of the alternatives of phase one, there was even CZ-2F crew rocket involved, with two CZ-5s being the cargo rockets. Phase two is CZ-5DY crew plus CZ-9 cargo. This is the paper I have read years ago. All these plans require earth orbit rendezvous (EOR).

However another paper (2009), EOR was deemed too complicated and risk of total mission failure is too high due to the earth orbit waiting and docking. This paper basically made the same conclusion as Apollo which also proposed and killed the idea of EOR. This is why I kept objecting the idea of multiple launches of smaller rockets in place of CZ-9 class.

It is worth to note that Long Lehao's paper is about the overall idea of moon mission, not in detailed study of various approach. The 2009 paper is the outcome of sub-study into details. So it should be taken more seriously.

I believe that based on the study of this paper, CNSA has committed to LOR (lunar Orbit Rendezous) which Apollo used. But there is a difference. Aopllo's LOR is only about the docking of ascent stage and the returning modules, one LOR. CNSA's plan has the docking of crew with the landing combo before the landing, two LOR. CNSA's approach will significantly increase the total mass to TLI 75t or more, compared to APOLLO's 50t.

In this new approach, CZ-5DY was deemed two light to send crew module to lunar orbit, so it is replaced by 921.

Both papers have envisioned both small scale and large scale landing. However it is worth noting the conclusion of the 2009 paper.
1606498252248.png
It says "we can conduct small scale (4 or 3 launches), OR go straight to large scale (2 launches, crew + cargo)."

It seems that by that time in 2009, both approaches are on the table, but there is no decision of having the small scale as first step. It could be a large scale as the first step too.

Regardless which approach, 921 is not alternative to CZ-9, it is the crew carrier which may act as a cargo carrier in place of CZ-9 IF 921 is much faster in progress than CZ-9. However, I doubt it will be faster enough to warrant a small scale approach, we are looking at between 2025(921 earliest) and 2030 (CZ-9). Considering 921 is manned rocket, it will need multiple un-crewed launches (3 to 4) before sending man to the moon, that will put its earliest manned mission to 2028.

One the one hand, 921 can be seen as a fast-track alternative before CZ-9 is ready, or we can equally say that "multiple 921 launches" is a backup in case of CZ-9 delay.
 
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taxiya

Colonel
Registered Member
LandSpace conducts tests on combined(?) TQ-11 and TQ-12 engines.


TQ-11 (10t) is the second stage vector control engine. So the combo works in the way that TQ-12 nozzle is fixed, while TQ-11 does the vector control.
 

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