China's Space Program Thread II

[Temstar]

The wire recovery method might still come up useful in other cases. For examples there are rumours that CALT is considering recovery for the upper stage for LM-10 family as well. One of the problem with recovering upper stage is since upper stage engines have to be vacuum optimized they generally have very large nozzles which makes any leg based solution problematic. You'll avoid that problem if you use the wire recovery method and since the upper stage is going to be much smaller you could conceivably recover upper stages of even very large rockets like LM-9. Deadweight on upper stages also impact the rocket's overall delta-V much more harshly than first stage due to the rocket equation so if you are going to recover the upper stage, having a method that adds as little weight in recovery hardware as possible is a big benefit.

The fact that wire recovery method can easily accommodate a whole range of rocket diameters is another bonus that could help with this. A whole bunch of rockets could share a single set of recovery ships.

 

[Blitzo]

The wire recovery method might still come up useful in other cases. For examples there are rumours that CALT is considering recovery for the upper stage for LM-10 family as well. One of the problem with recovering upper stage is since upper stage engines have to be vacuum optimized they generally have very large nozzles which makes any leg based solution problematic. You'll avoid that problem if you use the wire recovery method and since the upper stage is going to be much smaller you could conceivably recover upper stages of even very large rockets like LM-9.

This could actually be viable, if they are able to actually do the hard part of developing an upper stage that can survive re-entry.

The fact that wire recovery method can easily accommodate a whole range of rocket diameters is another bonus that could help with this. A whole bunch of rockets could share a single set of recovery ships.

Technically a single sized SpaceX or Blue Origin style (or iSpace, etc) flat recovery barge can also accommodate multiple rocket types that use legs to land as well; one only needs to develop a ship that is adequately sized for the largest rocket of a set, and then all the slightly smaller ones will also be able to land on the recovery barge.

 

[nativechicken]

This could actually be viable, if they are able to actually do the hard part of developing an upper stage that can survive re-entry.

Technically a single sized SpaceX or Blue Origin style (or iSpace, etc) flat recovery barge can also accommodate multiple rocket types that use legs to land as well; one only needs to develop a ship that is adequately sized for the largest rocket of a set, and then all the slightly smaller ones will also be able to land on the recovery barge.

The biggest problem with the landing-leg mode for touchdown on an offshore platform is that the first stage has a large length-to-diameter ratio (pencil-shaped vehicle), which makes it prone to tipping over in moderately high sea states. The net-capture scheme is much better.
The issue with the net is that it imposes a height limit on the lander. The current CZ-10B first stage appears to be around 40 meters tall. My personal estimate for the net-receiving platform height is about 70 meters. The CZ-10C first stage looks to be in the 50+ meter range, so the net platform would probably need to be 85–90 meters tall.
I believe that a net platform capable of recovering the CZ-10C first stage would most likely also be able to recover the CZ-9 first stage (since that stage is also in the 53–56 meter height range).

 

[Tomboy]

Well, they can tweak it to further increase the mass efficiency (common bulkheads, engine mass and ISP, optimum aerodynamic length etc.?) but at the end of the day it's still going to be a 5-metre diameter vechicle with many CZ-10 family tech; perhaps optimum mass efficiencies will be reserved for the future 7-metre class vehicle. And the true mass delivery truck to LEO (possibly also lunar) will be the various versions of CZ-9 in 5-7 years. They'll eventually have a range of vehicles to cover the complete mass-delivery and economic-efficiency spectrum: "right vechicle for the right price" rather than the one-size-fits-all hype for Starship (I don't think serious SpaceX insiders really believe that a LEO mass truck is the best option for interplanetary travel via refueling of cryogenic propellants; build dedicated cis-lunar and interplanetary transports for the love of [insert deity name here]).

CZ-10C already uses common bulkheads for tanks, perhaps YF-219 could also be further improved for more payload. Though insiders and some of the more credible posters like Cute Orca seems to be quite pessimistic on whether Chinese LVs could ever reach the level of weight reduction and optimisation of Falcon 9 which is rather concerning given how this might extrapolate to other related industries like commercial and more importantly military aviation.

Also, IMO no one believes Starship is going to be used for anything other than LEO truck which is arguably far more important anyways. Timely and mass access to LEO should be considered no less strategic than free access to the sea or air especially with the industrialisation and militarisation of space and unfortunately China doesn't seem to be catching up quickly enough here.

But hey, anything is better than nothing for the current situation especially that CZ-10C might be one of the first commercially viable and somewhat globally competitive LV to come out of China within the near future along with the alleged 20t reuse "full" CZ-12B and ZQ-3A.

 

[Temstar]

CZ-10C already uses common bulkheads for tanks, perhaps YF-219 could also be further improved for more payload. Though insiders and some of the more credible posters like Cute Orca seems to be quite pessimistic on whether Chinese LVs could ever reach the level of weight reduction and optimisation of Falcon 9 which is rather concerning given how this might extrapolate to other related industries like commercial and more importantly military aviation.

Also, IMO no one believes Starship is going to be used for anything other than LEO truck which is arguably far more important anyways. Timely and mass access to LEO should be considered no less strategic than free access to the sea or air especially with the industrialisation and militarisation of space and unfortunately China doesn't seem to be catching up quickly enough here.

But hey, anything is better than nothing for the current situation especially that CZ-10C might be one of the first commercially viable and somewhat globally competitive LV to come out of China within the near future along with the alleged 20t reuse "full" CZ-12B and ZQ-3A.

Some numbers for propellant mass fraction first:
Falcon 9 Block 5 - 95%
H-IIB - 92%
Long March 5 - 91%
Angara A5 - 89%
Ariane 5 - 89%
GSLV Mk II - 86%

Higher PMF is a sign of advanced rocket design, it means you can lift more mass with less rocket. You could always compensate for worse PMF by just building a bigger rocket. But obviously bigger rockets are more expensive.

US is really good at reducing dry mass yes, but this is an advantage that reusable rockets actually reduce. Since rocket is expensive but fuel is cheap you can always pay for a bigger reusable rocket initially with worse PMF for a given payload. The rocket may be more expensive but since you're reusing it the initial cost of building the rocket is spread out over many launches so it hurts less compared to an expendable rocket.

CALT has a reputation for being conservative and preferring to design robust rockets at the cost of lower PMF. Long March 5 gets the "conservative design and poor PMF" criticism all the time. But their approach may be quite suitable for reusable rockets. The CZ-10A test earlier this year for example has two out of four grid fins failing to deploy yet it didn't really affect the rocket control and it splashed down next to the recovery ship just fine with only two fins.

 

[Blitzo]

Some numbers for propellant mass fraction first:
Falcon 9 Block 5 - 95%
H-IIB - 92%
Long March 5 - 91%
Angara A5 - 89%
Ariane 5 - 89%
GSLV Mk II - 86%

Higher PMF is a sign of advanced rocket design, it means you can lift more mass with less rocket. You could always compensate for worse PMF by just building a bigger rocket. But obviously bigger rockets are more expensive.

US is really good at reducing dry mass yes, but this is an advantage that reusable rockets actually reduce. Since rocket is expensive but fuel is cheap you can always pay for a bigger reusable rocket initially with worse PMF for a given payload. The rocket may be more expensive but since you're reusing it the initial cost of building the rocket is spread out over many launches so it hurts less compared to an expendable rocket.

CALT has a reputation for being conservative and preferring to design robust rockets at the cost of lower PMF. Long March 5 gets the "conservative design and poor PMF" criticism all the time. But their approach may be quite suitable for reusable rockets. The CZ-10A test earlier this year for example has two out of four grid fins failing to deploy yet it didn't really affect the rocket control and it splashed down next to the recovery ship just fine with only two fins.

I think there is a difference between "higher dry mass is less of a detriment for reusable rockets" versus "lower dry mass is preferred overall if technology and processes allow".

I remain of the belief that a few differences in tonnage throw weight for medium or heavy lift rockets is not that big of a deal, if high pace reusability can be attained.


However, I also think there is some benefit for describing conservatism for what it is rather than suggesting it has any genuine benefit if all else is held equal (including technological capability). After all, a more "robust rocket" can simply be mitigated by designing a rocket that doesn't malfunction to begin with.

 

[Tomboy]

Some numbers for propellant mass fraction first:
Falcon 9 Block 5 - 95%
H-IIB - 92%
Long March 5 - 91%
Angara A5 - 89%
Ariane 5 - 89%
GSLV Mk II - 86%

Higher PMF is a sign of advanced rocket design, it means you can lift more mass with less rocket. You could always compensate for worse PMF by just building a bigger rocket. But obviously bigger rockets are more expensive.

US is really good at reducing dry mass yes, but this is an advantage that reusable rockets actually reduce. Since rocket is expensive but fuel is cheap you can always pay for a bigger reusable rocket initially with worse PMF for a given payload. The rocket may be more expensive but since you're reusing it the initial cost of building the rocket is spread out over many launches so it hurts less compared to an expendable rocket.

CALT has a reputation for being conservative and preferring to design robust rockets at the cost of lower PMF. Long March 5 gets the "conservative design and poor PMF" criticism all the time. But their approach may be quite suitable for reusable rockets. The CZ-10A test earlier this year for example has two out of four grid fins failing to deploy yet it didn't really affect the rocket control and it splashed down next to the recovery ship just fine with only two fins.

While I do agree with your points that reusability makes PMF less of a absolute indicator for efficiency but it doesn't make it completely redundant. IMO, eventually, just like commercial airliners, the "fuel efficiency" of a LV will become a critical performance benchmark once reusablility has become a commodity in the industry. Fuel is cheap relative to the rocket itself but isn't free, that extra hundred or two tonnes of kerosene/methane and LOX for a similarly sized payload will eventually add up in costs over dozens of flights.

 

[nativechicken]

Some numbers for propellant mass fraction first:
Falcon 9 Block 5 - 95%
H-IIB - 92%
Long March 5 - 91%
Angara A5 - 89%
Ariane 5 - 89%
GSLV Mk II - 86%

Higher PMF is a sign of advanced rocket design, it means you can lift more mass with less rocket. You could always compensate for worse PMF by just building a bigger rocket. But obviously bigger rockets are more expensive.

US is really good at reducing dry mass yes, but this is an advantage that reusable rockets actually reduce. Since rocket is expensive but fuel is cheap you can always pay for a bigger reusable rocket initially with worse PMF for a given payload. The rocket may be more expensive but since you're reusing it the initial cost of building the rocket is spread out over many launches so it hurts less compared to an expendable rocket.

CALT has a reputation for being conservative and preferring to design robust rockets at the cost of lower PMF. Long March 5 gets the "conservative design and poor PMF" criticism all the time. But their approach may be quite suitable for reusable rockets. The CZ-10A test earlier this year for example has two out of four grid fins failing to deploy yet it didn't really affect the rocket control and it splashed down next to the recovery ship just fine with only two fins.

Most Western rockets today are hydrogen-oxygen powered. Hydrogen-oxygen propulsion tends to result in a relatively low dry-mass fraction (low propellant density leads to lower specific impulse in terms of density, larger fuel tanks). Solid rocket boosters and strap-on configurations also degrade the dry-mass fraction indicator.
The Falcon 9 represents a series of extreme design choices that are hard for others to replicate. First, it uses aluminum-lithium alloy, which most other rockets do not. Second, its engines have a simple structure and are relatively light. The YF-100 series weighs 1.5–1.8 tons per engine, about 1–1.3 tons heavier than the Falcon 9's Merlin 1D each. Just the first-stage engines alone add nearly 10 tons of excess weight. The YF-100 can't help it—the basic engine was designed that way, and it can't be swapped out in the short term.
My estimate puts the first-stage dry mass at 42–45 tons. The Falcon 9's is reportedly only 22 tons.
The author observes that Falcon 9's low dry mass enables a favorable thrust-to-weight ratio at landing, whereas the YF-100's limited throttle range (only 30%) makes such soft hovering harder to achieve—unless the vehicle is very light. The translation preserves the casual analytical tone ("it's clear," "that's why").
The Falcon 9's dry-mass fraction is exceptionally high, and it's unlikely anyone will try to match it. There's not much need. As long as the core total cost and unit launch cost are lower than the Falcon 9's, that's enough to win. For example, aluminum-lithium alloy is much more expensive than aluminum-magnesium or aluminum-copper alloys, and the fabrication process is trickier—plus the development and trial-and-error costs need to be amortized. That's disadvantageous for private aerospace companies (most probably won't rush to adopt it). In the US, aluminum-lithium was mainly used in the Space Shuttle's external tank for years. China has only recently produced a 3-meter diameter upper-stage tank out of this alloy, and it may not even have flown yet. Under cost-priority considerations, materials like aluminum-lithium (expensive and immature) are basically not used—no one wants to be the guinea pig bearing the verification risk.
This passage continues the previous thread about Falcon 9 vs. Chinese rocket design.

 

[nativechicken]

While I do agree with your points that reusability makes PMF less of a absolute indicator for efficiency but it doesn't make it completely redundant. IMO, eventually, just like commercial airliners, the "fuel efficiency" of a LV will become a critical performance benchmark once reusablility has become a commodity in the industry. Fuel is cheap relative to the rocket itself but isn't free, that extra hundred or two tonnes of kerosene/methane and LOX for a similarly sized payload will eventually add up in costs over dozens of flights.

Aerospace-grade liquid oxygen runs about ¥1,320/ton, RP-1 (kerosene) ¥20,000/ton, and liquid methane ¥8,000/ton. Adding that bit of cost doesn't dent competitiveness at all.
As for SpaceX — its Falcon 9 reused launch cost is $15 million internally, but it sells at $70 million+ per launch (commercial price; for government/military and crewed procurement, the per-launch price is far above $100 million). On the Chinese side, some people have been talked into believing the Falcon 9 launch price really is $15 million — see LandSpace's Chinese-language paper, for instance. They're trying to peg their own reused launch pricing within that range. My estimate is that once the tech matures domestically, the reused launch price in China will be around ¥25–30 million per launch (Falcon 9 class).
Tell me who cares about that 100–200 tons of propellant cost. It's smaller than the added shipping cost of offshore recovery alone (a single recovery voyage might run $1 million).

Actually, Europe and the US don't need to worry that China's reusable rockets will have any impact on SpaceX's market position. As I said earlier, this kind of impact doesn't exist—because the markets are segregated.

The entire satellite market is essentially US-dominated. It took China over 20 years from the turn of the century to achieve full technological autonomy.

And because of the so-called Wen Ho Lee case (he was framed) back in 1998, the US already ruled that no satellite containing even a shred of US technology can be launched on a Chinese rocket. More than ten years ago, if China needed any US tech, it required special approval. After 2010, at most China could lean on European tech to get by for a while—and later even European tech became hard to get (now it's not needed anymore).

So the real situation is: whether China has reusable tech or not makes no difference to SpaceX's development, and likewise, SpaceX's development can't affect China's space tech iteration at all.

Every time I see someone talking about China-US space competition, or "impact," I just laugh. If SpaceX runs into trouble, the biggest reason won't be some Chinese space tech advancement. It'll be that they shouldn't keep running so many reckless projects and burning money chaotically—then they could stay ahead for a long, long time.

For instance, if Starship V1/V2 hadn't insisted on second-stage reuse and instead used a traditional expendable upper stage, it could've been declared a success ages ago, taking over the SLS Block 1/1B/2 missions. Then they could've iterated slowly toward full-reuse second stage. This is something any slightly seasoned aerospace expert worldwide understands. But SpaceX just wouldn't do it—had to insist, and now it's still not even reached orbit, holding up the entire Artemis program schedule. And then there's that overweight pencil-shaped lunar HLS. Given SpaceX's whole "blow up rockets and learn" engineering principle, do you really trust them to nail the first Moon landing without issues?

Are all these dragging-everything-down problems supposed to be blamed on Chinese reusable rocket competition? Purely SpaceX messing itself up.

 

[broadsword]

Most Western rockets today are hydrogen-oxygen powered. Hydrogen-oxygen propulsion tends to result in a relatively low dry-mass fraction (low propellant density leads to lower specific impulse in terms of density, larger fuel tanks). Solid rocket boosters and strap-on configurations also degrade the dry-mass fraction indicator.
The Falcon 9 represents a series of extreme design choices that are hard for others to replicate. First, it uses aluminum-lithium alloy, which most other rockets do not. Second, its engines have a simple structure and are relatively light. The YF-100 series weighs 1.5–1.8 tons per engine, about 1–1.3 tons heavier than the Falcon 9's Merlin 1D each. Just the first-stage engines alone add nearly 10 tons of excess weight. The YF-100 can't help it—the basic engine was designed that way, and it can't be swapped out in the short term.
My estimate puts the first-stage dry mass at 42–45 tons. The Falcon 9's is reportedly only 22 tons.
The author observes that Falcon 9's low dry mass enables a favorable thrust-to-weight ratio at landing, whereas the YF-100's limited throttle range (only 30%) makes such soft hovering harder to achieve—unless the vehicle is very light. The translation preserves the casual analytical tone ("it's clear," "that's why").
The Falcon 9's dry-mass fraction is exceptionally high, and it's unlikely anyone will try to match it. There's not much need. As long as the core total cost and unit launch cost are lower than the Falcon 9's, that's enough to win. For example, aluminum-lithium alloy is much more expensive than aluminum-magnesium or aluminum-copper alloys, and the fabrication process is trickier—plus the development and trial-and-error costs need to be amortized. That's disadvantageous for private aerospace companies (most probably won't rush to adopt it). In the US, aluminum-lithium was mainly used in the Space Shuttle's external tank for years. China has only recently produced a 3-meter diameter upper-stage tank out of this alloy, and it may not even have flown yet. Under cost-priority considerations, materials like aluminum-lithium (expensive and immature) are basically not used—no one wants to be the guinea pig bearing the verification risk.
This passage continues the previous thread about Falcon 9 vs. Chinese rocket design.

Do you mean exceptionally low?