Author Topic: China to have new rockets  (Read 423108 times)

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Offline DreamyPickle

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Re: China to have new rockets
« Reply #581 on: 12/22/2020 02:24 pm »
There doesn't seem to be any dedicated CZ-8 thread so I'll just ask here instead of the dedicated launch thread: Why have boosters on a reusable system?

The core and side-boosters have the same fuel, same engine and in the reusable configuration the booster will not detach. Simply having a larger single core would be better in every way.

This seems like a kludge motivated entirely by expediency: they don't have tooling for a bigger diameter so they just tied some smaller cores together. But looking at China's rockets I already see a bewildering variety of diameters.

Online spacenut

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Re: China to have new rockets
« Reply #582 on: 12/22/2020 02:38 pm »
They probably have a transportation problem like Russia, especially in the interior.  Rail only.  Harder to build large rockets except near waterways or sea coasts.  Most of China's population lives close to the coast so very little room.  Interior has a very poor transportation system.  No interstate highways, very few rail lines in the interior. 

The only real way to get a heavy lifter for either China or Russia is clustering the boosters.  Saturn V was built near a larger waterway.  Starship/Superheavy is being built near it's launch pad and can be delivered offshore.  I am surprised China hasn't built a launch facility in south China along the coast or the large island off Vietnam.  It is closer to the equator and a large rocket could be delivered by ship from North China.  I think sometimes they don't want people knowing what they are doing, especially free world media. 

Offline PM3

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Re: China to have new rockets
« Reply #583 on: 12/22/2020 02:47 pm »
Lots of Chinese Hopping activity expected in 2021.

CZ-8 hopper, SQX-2 (Hyperbola-2) hopper, hopefully a Newline-1 hopper, and Andrew Jones also mentions a TianBin hopper (per attachment from his tweet, see below).

Partially reusable CZ-8 (CZ-8R) aims entering service in 2025, and by 2030 they want to make it fully reusable.
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Offline Prettz

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Re: China to have new rockets
« Reply #584 on: 12/22/2020 02:50 pm »
There doesn't seem to be any dedicated CZ-8 thread so I'll just ask here instead of the dedicated launch thread: Why have boosters on a reusable system?

The core and side-boosters have the same fuel, same engine and in the reusable configuration the booster will not detach. Simply having a larger single core would be better in every way.

This seems like a kludge motivated entirely by expediency: they don't have tooling for a bigger diameter so they just tied some smaller cores together. But looking at China's rockets I already see a bewildering variety of diameters.
I think you answered your own question. It looks to be more-or-less the CZ-7 first stage with 2 fewer boosters and the CZ-3B's third stage as its second stage. Seems to me to be ALL about expediency.

Although it doesn't seem like a good idea for planning for the future, wedding yourself to the legacy tank designs for your new, next-generation rockets.

They probably have a transportation problem like Russia, especially in the interior.  Rail only.  Harder to build large rockets except near waterways or sea coasts.  Most of China's population lives close to the coast so very little room.  Interior has a very poor transportation system.  No interstate highways, very few rail lines in the interior. 

The only real way to get a heavy lifter for either China or Russia is clustering the boosters.  Saturn V was built near a larger waterway.  Starship/Superheavy is being built near it's launch pad and can be delivered offshore.  I am surprised China hasn't built a launch facility in south China along the coast or the large island off Vietnam.  It is closer to the equator and a large rocket could be delivered by ship from North China.  I think sometimes they don't want people knowing what they are doing, especially free world media.
CZ-5, -7, and -8 are launched from the new coastal launch site. It has ship access for big rocket stages.

Offline DreamyPickle

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Re: China to have new rockets
« Reply #585 on: 12/22/2020 03:02 pm »
They probably have a transportation problem like Russia, especially in the interior.  Rail only.  Harder to build large rockets except near waterways or sea coasts.  Most of China's population lives close to the coast so very little room.  Interior has a very poor transportation system.  No interstate highways, very few rail lines in the interior. 

The only real way to get a heavy lifter for either China or Russia is clustering the boosters.  Saturn V was built near a larger waterway.  Starship/Superheavy is being built near it's launch pad and can be delivered offshore.  I am surprised China hasn't built a launch facility in south China along the coast or the large island off Vietnam.  It is closer to the equator and a large rocket could be delivered by ship from North China.  I think sometimes they don't want people knowing what they are doing, especially free world media. 
That large island is Hainan and that is where CZ-8 launched from. Most rockets are still launched from deep inland locations.

China has lots of big rivers and they mostly flow towards the populated coast, sort of like the Mississippi. This is a much better situation than in Russia where major rivers flow into the arctic or internal lakes, and Russia is just physically much larger. They're also famous for spending ridiculous amounts on infrastructure.

It's possible that major manufacturing for rockets was placed in extremely remote areas for military reasons and they had trouble shipping rocker tanks of the appropriate diameters to Hainan

Offline Lars-J

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Re: China to have new rockets
« Reply #586 on: 12/22/2020 11:11 pm »
Most of China's population lives close to the coast so very little room.  Interior has a very poor transportation system.  No interstate highways, very few rail lines in the interior.

I think your information is ... a bit out of date. :)

1. China's population is not just at the coast. The entire eastern half of the country has high population density. (See image)

2. China has spent an incredible amount on infrastructure in the last decades, and now have a vast highway and rail network. And its rail network would be the envy of ANY nation: https://en.wikipedia.org/wiki/High-speed_rail_in_China
 
3. And the expressway system is impressive: https://en.wikipedia.org/wiki/Expressways_of_China - its length is now roughly 3 times the US interstate system.

The only launch site of theirs which would qualify as very remote is Jiuquan. The others have decent infrastructure access, and it is getting better.
« Last Edit: 12/23/2020 04:55 am by Lars-J »

Offline baldusi

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Re: China to have new rockets
« Reply #587 on: 12/23/2020 01:59 am »
What's maximum diameter and length of train transported structures? They might have the most impressive highways and train lines but if they are restricted to 3.35m x 25m they still are transport limited.

Offline luhai167

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Re: China to have new rockets
« Reply #588 on: 12/24/2020 08:24 am »
For standard rail carts, 13 m x 3 x 3. Absolute maximum would be unspecified length x 5.5 m x 4.3 m, that would require special rail carts.


http://www.chmc.cc/contents/152/41172.html
« Last Edit: 12/24/2020 08:26 am by luhai167 »

Offline baldusi

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Re: China to have new rockets
« Reply #589 on: 12/24/2020 01:05 pm »
For standard rail carts, 13 m x 3 x 3. Absolute maximum would be unspecified length x 5.5 m x 4.3 m, that would require special rail carts.


http://www.chmc.cc/contents/152/41172.html

You need certain margins on the bottom, to the sides and to consider the vibrations environment. You also need to consider the minimum radius of turns in the whole way and then calculate how that restricts your width given your length. So I wouldnít be surprised if 3.35m was the limit they calculated as the maximum common denominator from the factory to all launch sites. I think for the Russians that was 3.8m, the can send 4.1m from Moscow to Bailonour but they canít cross another train during the whole trip and itís impossible to do to the East. Chine might have a couple of tight tunnels or bridges through some of their trips to some launch site.

Offline Prettz

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Re: China to have new rockets
« Reply #590 on: 12/24/2020 02:36 pm »
Where are most of their rocket stages built? I think we heard the 5m stages for CZ-5 are built in Tianjin, right? Are the smaller diameter stages also built near the coast?

Offline luhai167

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Re: China to have new rockets
« Reply #591 on: 12/24/2020 05:31 pm »
Where are most of their rocket stages built? I think we heard the 5m stages for CZ-5 are built in Tianjin, right? Are the smaller diameter stages also built near the coast?
Beijing, or at least that's the long trip starts. Here is information straight from horse's mouth. Also notice in the image they are using standard carts with some overhang.

http://calt.spacechina.com/n482/n756/c5912/content.html

Offline tangdou8

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Re: China to have new rockets
« Reply #592 on: 05/01/2021 08:02 am »
Some updates on new rockets

First, SAST's new medium Commercial launcher (consider it similar to F9 v1.0?). Tentative maiden flight is scheduled for 2023.
Height: 59m. Take-off weight: 433t. Take off thrust: 5000KN.
[email protected]: 10T, [email protected]: 5t
First stage: 4 * YF100k engines, second stage: 2* YF115

This rocket is believed to be the single core version for SAST's 921 rocket (5*4 YF100K with 3.8 diameter)


Offline tangdou8

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Re: China to have new rockets
« Reply #593 on: 05/01/2021 08:16 am »
Here are some presentation slides from China Space Day

First image is the comparison of YF-100, YF-100K, YF-100M (vac)
YF 100K:
Throttle range: 65% to 105%; Thrust to Weight ratio: 75

YF-100M: nozzle diameter: 2.16m, nozzle ratio: 90

Second image has a comparison of two New gen manned launcher on the right. Left one is CALT's 3*7 YF-100k version, and the right one is SAST's 5 * 4 YF100K version. Both use 2 * YF100M for the second stage.

Also, on the left, there are notations showing 2025 crewed lunar fly by mission and 2030 crewed lunar landing mission...

The third one showing the diameter of CALT's launcher is 5m with 27t LTO

« Last Edit: 05/01/2021 09:06 am by tangdou8 »

Offline tangdou8

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Re: China to have new rockets
« Reply #594 on: 05/01/2021 08:31 am »
The last one is 200t LOX/methane engine

low-cost full-flow stage combustion
throttle range: 25% -110%
sea level thrust: 2000kN
sea level impulse: >= 327s
Thrust to weight ratio >= 90
could be reused for >= 20 times

The second image shows possible config for this engine. 5m diameter with 3 or 5, and 7.5m diameter with 9


Offline Lars-J

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Re: China to have new rockets
« Reply #595 on: 05/01/2021 05:55 pm »
The last one is 200t LOX/methane engine

low-cost full-flow stage combustion
throttle range: 25% -110%
sea level thrust: 2000kN
sea level impulse: >= 327s
Thrust to weight ratio >= 90
could be reused for >= 20 times

The second image shows possible config for this engine. 5m diameter with 3 or 5, and 7.5m diameter with 9
The specs for this last one is almost an exact match for Raptor. (Not surprising they would want a similarly capable engine)

But is it more of a specification wishlist than something that is in the middle of development? I suspect the former.

Offline luhai167

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Re: China to have new rockets
« Reply #596 on: 05/01/2021 08:01 pm »
The last one is 200t LOX/methane engine

low-cost full-flow stage combustion
throttle range: 25% -110%
sea level thrust: 2000kN
sea level impulse: >= 327s
Thrust to weight ratio >= 90
could be reused for >= 20 times

The second image shows possible config for this engine. 5m diameter with 3 or 5, and 7.5m diameter with 9
The specs for this last one is almost an exact match for Raptor. (Not surprising they would want a similarly capable engine)

But is it more of a specification wishlist than something that is in the middle of development? I suspect the former.
Yes, the Chinese text in the slide say specifications benchmark against the most advanced reusable LOX/methane engine of today, which would be the raptor. Also since this is a benchmark, so it is very much a wishlist.

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Re: China to have new rockets
« Reply #597 on: 06/17/2021 06:45 am »
According to the official China Space News, it was decided (as many have suspected) that a 2-stage "RP-1/LOX core only" version of the "921 rocket" as mentioned earlier (perhaps with 1 engine on 2nd stage instead of the full version's 2) will be used for LEO missions of the next generation Chinese crew S/C, with capability of around 20 tonnes.

https://mp.weixin.qq.com/s/TtVQ0stCTGx7oM1LQHKOQA
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Offline Steven Pietrobon

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Re: China to have new rockets
« Reply #598 on: 06/19/2021 03:45 am »
Here are the relevant paragraphs.

"Zhang Zhi revealed that the new generation of manned rockets used for manned landing on the moon is over 100 meters high, using a three-stage semi-configuration, earth-moon transfer orbit carrying capacity of nearly 25 tons, on the basis of inheriting the mature technology of the Long March 5 and Long March 7 rockets, innovative upgrade escape system and fault detection and diagnosis system to further ensure the safety of astronauts.

It is understood that China's manned lunar landing program of the original 6 kinds, after many arguments, finally determined and "Artemis plan" similar program, that is, two launches, respectively, manned spacecraft and lunar lander into lunar orbit, the two in the lunar orbit rendezvous and docks, in the form of a combination of flight for a period of time and then separated, astronauts aboard the lander landing on the moon. After the scientific expedition, the astronauts took off from the moon aboard the ascending device, entered the lunar orbit and docked with the manned spacecraft, and abandoned the ascender and returned to Earth after the transfer.

Manned rockets used in low-Earth orbit evolved from manned lunar landings. Zhang Zhi said the two-stage structure of the rocket, low-Earth orbit carrying capacity of nearly 20 tons, will promote China's manned space industry into a new stage."
« Last Edit: 06/19/2021 03:51 am by Steven Pietrobon »
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline tangdou8

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Re: China to have new rockets
« Reply #599 on: 06/19/2021 08:47 am »
A new presentation slide showing more accurate numbers of take-off weight and take-off thrust for the 921 rocket.

LEO capability: 70t (CZ-2F: 8.6t)
LTO: 25t
take-off weight: 2211t
take-off thrust: 2680t
« Last Edit: 06/19/2021 08:48 am by tangdou8 »

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