China's Space Program News Thread

[gelgoog]

hmm, now you are trying to shift the goal post, that is not honest of you. Did I saying anything refuting these things that you are trying to stuff into the conversation? Did I even mention anything related to these "new" points of yours?
...

You are the one ignoring the strategic implications of reusability and giving way too much value just because someone is using LOX/LH2.

I made it perfectly clear that LOX/LH2 isn't even the highest Isp solution you can use. Which you claimed as if it was the only metric of merit in a rocket. Which it isn't. In the first stage of a rocket the metric of merit is high thrust to weight ratio to reduce gravity losses. For that you need high thrust to weight engines, low dry mass fraction of the rocket, dense fuel. Which liquid hydrogen is not. Only once you escape the confines of Earth's atmosphere does high Isp become more relevant.

The fact is, it would have been easier, not harder, for SpaceX to develop a LOX/LH2 engine with similar technology level than LOX/LCH4. The combustion is a lot cleaner and you don't need as many treatments and advanced alloys in the engine for it to work. But it would come at the cost of heavy fuel tanks. You would need much larger tanks because of its low density and you would need insulation on the tanks to keep the liquid hydrogen, which is deeply cryogenic unlike LOX or LCH4, below boiling temperature. Which would reduce useful payload for the same size rocket.

LOX/LH2 is nice to have in 2nd stages but many successful launcher rockets in the past and today don't use it anywhere at all. Soyuz is arguably the most successful rocket launcher in history and it does not use it. Neither does Proton. Neither does Falcon 9. I know ONE exactly ONE rocket which uses LOX/LH2 in the first stage and that is the USA Delta IV Heavy rocket. It is horrendously expensive and is being phased out from usage. To reduce the dry mass fraction Boeing uses isogrid tank construction which requires time consuming machining of tanks. Each tank, and it has three, is more expensive to manufacture than all of a Falcon Heavy's tanks. All other LOX/LH2 rocket designs at best use parallel staging with most of the thrust either coming from solid side boosters like Ariane 5/H-IIA/Shuttle or use LOX/Kerosene side boosters like Energia/Long March 5 thus not being true LOX/LH2 first stages. In a lot of cases in these rockets, like the Ariane 5, the LOX/LH2 rocket engine it has (Vulcain) can't even liftoff the weight of itself and the center fuel tanks. So it can't even liftoff without side boosters.

Thankfully China itself, unlike you it seems, sees the value of reusability and there are several private efforts attempting this and even the state sponsored launcher has decided to change its launch rocket plans.

 

[longmarch]

Oh God. Is China's space industry that incompetent?

Today China launches more rockets than US. and you start to worry one day US will launch 10 times more.

When US landed on the moon, China couldn't launch a potato to space (Mao's word) look at where they are now.

What Elon Musk is doing is evolution, not revolution. Period. China is happily letting him try things out, then quickly follow. Meanwhile China is doing other things that Musk is not doing.

Tencent happily invested in Tesla when Musk running out of money. It's not like China wants him to fail. Have some confidence.

 

[Temstar]

Even discounting the commercial side, remember that SpaceX is launching payloads for the military. If payloads to space get 10 times cheaper for the US, that is 10 times more US assets in space, assuming constant budget.

2: Try to brute-force it by subsidizing more costly rockets, draining resources while stunting domestic growth.

These two statements are actually contradictory, let me explain why that's so.

In terms of cheap access to space there are actually two schools of thoughts on how to achieve this (setting aside the really big infrastructure ideas like space elevators, laser launcher etc):

1. Reusability - SpaceX, Space shuttle, Skylon etc etc, bringing down cost by reusing hardware
2. Big Dumb Booster

Big dumb boosters aim to bring down cost using by using economy of scale. Instead of rockets being individual works of art using all super expensive material and squeezing every last drop of performance out of the engines, BDB instead call for powerful but simple rockets which may have lower payload efficiency, yet be cheaper to operate as a program, particularly as you scale up the size of your space program and call for more and more launches, meaning more and more BDBs getting built and economy of scale kicking in with manufacturing.

Russia tend to go for the BDB approach. You can see this by the fact that they're still using R-7 rocket family (rolling them off the assembly line like sasuages, as it were), and on top of this all of their rockets from R-7 family to Proton to even N1 can all be built horizontally, rolled out to the pad and then erected vertically. American rockets are much less robust and all have to be stacked vertically in the VAB.

China is somewhere in between the two approaches. However if you say we need to launch 10 times more payload than we are now as a matter of national security it's not certain which of the two approaches actually offer cheaper access to space.

 

[Arcgem]

These two statements are actually contradictory, let me explain why that's so.

In terms of cheap access to space there are actually two schools of thoughts on how to achieve this (setting aside the really big infrastructure ideas like space elevators, laser launcher etc):

1. Reusability - SpaceX, Space shuttle, Skylon etc etc, bringing down cost by reusing hardware
2. Big Dumb Booster

Big dumb boosters aim to bring down cost using by using economy of scale. Instead of rockets being individual works of art using all super expensive material and squeezing every last drop of performance out of the engines, BDB instead call for powerful but simple rockets which may have lower payload efficiency, yet be cheaper to operate as a program, particularly as you scale up the size of your space program and call for more and more launches, meaning more and more BDBs getting built and economy of scale kicking in with manufacturing.

Russia tend to go for the BDB approach. You can see this by the fact that they're still using R-7 rocket family (rolling them off the assembly line like sasuages, as it were), and on top of this all of their rockets from R-7 family to Proton to even N1 can all be built horizontally, rolled out to the pad and then erected vertically. American rockets are much less robust and all have to be stacked vertically in the VAB.

China is somewhere in between the two approaches. However if you say we need to launch 10 times more payload than we are now as a matter of national security it's not certain which of the two approaches actually offer cheaper access to space.

Why not have it both ways instead of choosing just one or a half-and-half middle ground? If Starship gets off the ground (and back, in one piece) it will be:

1. reusing boosters.
2. cheaper to build (stainless steel is heavier, which cuts into payload) while also being massive.

These two combined would absolutely achieve economies of scale. Not only do your rockets come back after each launch, they don't even have to squeeze out every drop of performance because they can just launch again. Scaling up is easy, just build another rocket.

 

[gelgoog]

Well the thing is SpaceX already pretty much adheres to the simple rocket design philosophy. I mean just compare Falcon 9 with Atlas V.
Instead of designing two engines, one for each stage, they use the same basic engine design on both stages. They use simple fuel tanks which require minimum fabrication. The engines are also simple to manufacture gas-generator designs. They manufacture the engines in large quantities so they get economies of scale by making hundreds of engines instead of only a couple of them in an artisanal workshop.

China, it seems to me, took best practices of the rockets in the 1990s and designed their current generation rockets based on that. It wasn't a bad idea. They have better rockets today than nearly everyone. China dominates the staged combustion cycle with LOX/Kerosene while the USA still needs to import Russian engines. SpaceX and Blue Origin new rocket engines are supposed to replace Russian staged combustion engines of RD-170 family like the RD-180 on Atlas V. But rockets which will use those engines are still not in production and might only be in 5 years.

For next generation rocket designs I think China needs to opt for a reduction in the amount of different launch vehicle types they use, use a universal rocket module, plus implement reusability in their rockets. The 921 rocket is a great design because a single core of it with 7x YF-100 engines can replace Long March 7 at ease. While a triple core with 21x YF-100 engines can replace the Long March 5 and then some. With increased production rate of the same basic rocket modules and engines economies of scale can be reached and lower cost per flight can be attained. Then if they manage to make it reusable you'll get another cost reduction on top of that. Let's say they manage to reuse the stages half a dozen times. That could reduce costs to a quarter.

While I agree that there is no rush to compete and that being a decade behind isn't too much of a problem, certain technologies need to begin development right now if China is to compete with current USA rockets, let alone future ones. To a large degree a lot of USA government payloads are still launched on Delta IV/Atlas V so the cost reduction factor of the Falcon 9 is still not fully reflected on government payloads. Once it is then you might see an increase in USA space assets. One sign of this intent is the creation by the USA of the Space Force as a separate arm from the USAF. The US wants a dedicated agency to control its in space assets. This is only the case because they see a need for more focus on satellites and space technology in the next decade.

China has the launch vehicles it needs right now but the 921 rocket is, I think, of prime importance for the next decade in case they want to remain ascendant. Plus they have to do work on reusability right now so it will be ready sometime over the next decade even if it is near the end of it.

Things like Starship I am not too concerned about them, I think it is overly complicated as a rocket like I said before, but the Raptor engine is a fearsome design, if designed into a proper rocket, and SpaceX's recent achievement of the belly flop manuever is no small achievement unlike some people think. NASA in the 1990s tried to do a flip maneuver with the DC-XA vehicle and the vehicle imploded in flight as the fuel sloshed around and burst the fuel tanks. The fuel tanks couldn't withstand the change in orientation of the vehicle. It was a more complex maneuver, sure, it was a bottom-up flip instead of a sideways flip, but do not underestimate the difficulty of doing that with the tanks and the plumbing continuing to work. Plus they demonstrated active control of the descent with the winglets. Another non-trivial thing to do. If those work properly then the rocket can likely return back to launch site instead of having to land on a barge or whatever. I also don't think the steel construction is a minus factor. It actually demonstrates a rational economic approach to the problem. It is much cheaper and has more strength per weight than the alternatives for these cryogenic fuels. My main gripe with the design, besides the whole thing being huge, is the reentry phase where they want to use heat tiles. Those seem like a failed move to me.

 

[discspinner]

Well the thing is SpaceX already pretty much adheres to the simple rocket design philosophy. I mean just compare Falcon 9 with Atlas V.
Instead of designing two engines, one for each stage, they use the same basic engine design on both stages. They use simple fuel tanks which require minimum fabrication. The engines are also simple to manufacture gas-generator designs. They manufacture the engines in large quantities so they get economies of scale by making hundreds of engines instead of only a couple of them in an artisanal workshop.

China, it seems to me, took best practices of the rockets in the 1990s and designed their current generation rockets based on that. It wasn't a bad idea. They have better rockets today than nearly everyone. China dominates the staged combustion cycle with LOX/Kerosene while the USA still needs to import Russian engines. SpaceX and Blue Origin new rocket engines are supposed to replace Russian staged combustion engines of RD-170 family like the RD-180 on Atlas V. But rockets which will use those engines are still not in production and might only be in 5 years.

For next generation rocket designs I think China needs to opt for a reduction in the amount of different launch vehicle types they use, use a universal rocket module, plus implement reusability in their rockets. The 921 rocket is a great design because a single core of it with 7x YF-100 engines can replace Long March 7 at ease. While a triple core with 21x YF-100 engines can replace the Long March 5 and then some. With increased production rate of the same basic rocket modules and engines economies of scale can be reached and lower cost per flight can be attained. Then if they manage to make it reusable you'll get another cost reduction on top of that. Let's say they manage to reuse the stages half a dozen times. That could reduce costs to a quarter.

While I agree that there is no rush to compete and that being a decade behind isn't too much of a problem, certain technologies need to begin development right now if China is to compete with current USA rockets, let alone future ones. To a large degree a lot of USA government payloads are still launched on Delta IV/Atlas V so the cost reduction factor of the Falcon 9 is still not fully reflected on government payloads. Once it is then you might see an increase in USA space assets. One sign of this intent is the creation by the USA of the Space Force as a separate arm from the USAF. The US wants a dedicated agency to control its in space assets. This is only the case because they see a need for more focus on satellites and space technology in the next decade.

China has the launch vehicles it needs right now but the 921 rocket is, I think, of prime importance for the next decade in case they want to remain ascendant. Plus they have to do work on reusability right now so it will be ready sometime over the next decade even if it is near the end of it.

Things like Starship I am not too concerned about them, I think it is overly complicated as a rocket like I said before, but the Raptor engine is a fearsome design, if designed into a proper rocket, and SpaceX's recent achievement of the belly flop manuever is no small achievement unlike some people think. NASA in the 1990s tried to do a flip maneuver with the DC-XA vehicle and the vehicle imploded in flight as the fuel sloshed around and burst the fuel tanks. The fuel tanks couldn't withstand the change in orientation of the vehicle. It was a more complex maneuver, sure, it was a bottom-up flip instead of a sideways flip, but do not underestimate the difficulty of doing that with the tanks and the plumbing continuing to work. Plus they demonstrated active control of the descent with the winglets. Another non-trivial thing to do. If those work properly then the rocket can likely return back to launch site instead of having to land on a barge or whatever. I also don't think the steel construction is a minus factor. It actually demonstrates a rational economic approach to the problem. It is much cheaper and has more strength per weight than the alternatives for these cryogenic fuels. My main gripe with the design, besides the whole thing being huge, is the reentry phase where they want to use heat tiles. Those seem like a failed move to me.

Do you think it will work for a MARS landing? Sparse atmospher, 6x terminal velocity of earth. It's going to be hard to even collect data when they inevitably fail the first couple of attempts
Overly complicated for moon bases
Also, how do you guarantee a relatively flat landing location on the moon or Mars? Trying to land a 2 story pyramid vs landing a 20 story building

 

[HybridHypothesis]

If SpaceX is successful with their whole refuelling thing is there any reason why China wouldn't take advantage of their service?

Like hey, if you can lift tanks full of liquid oxygen and methane into low earth orbit and have the tech to transfer them, then give us the specifications for your docking port and we'll shortly launch a giant Mars-capable spacecraft sans fuel into orbit with our Long March 9 and you can fuel it up for us.

They are after all in business to make money no?

wow dude, you still think the American gov cares more about money than politics at this point

 

[by78]

Just watched the Starship flight yesterday. Holy shit. China lost sooo much time in the 2 1/2 years after the July 2017 Long March 5 explosion... it is massively behind now.

This is exactly the kind of low effort, off-topic post we are trying to avoid. In case you haven't noticed, comparison posts of this nature is forbidden by the forum rules, precisely because we want to avoid the pages of derailed discussions that followed.

 

[Hitchhiker]

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The lunar rocks leaving lunar orbit soon.

"The orbiter-returner combination of China's Chang'e-5 probe on Saturday completed an orbital maneuver, preparing to leave the lunar orbit for a trajectory that returns it to Earth,"

 

[Quickie]

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Update: Chang'e-5 orbiter-returner completes orbital maneuver to prepare for return



A graphic simulation shows the orbit of the orbiter and returner combination of China's Chang'e-5 probe after its separation from the ascender. (CNSA/Handout via Xinhua)

BEIJING, Dec. 12 (Xinhua) -- The orbiter-returner combination of China's Chang'e-5 probe on Saturday completed an orbital maneuver, preparing to leave the lunar orbit for a trajectory that returns it to Earth, according to the China National Space Administration.
After about six days in lunar orbit, the orbiter-returner combination completed the maneuver at 9:54 a.m. (Beijing Time), changing from a nearly circular orbit to an elliptical orbit with a perilune altitude of 200 km.
The orbiter-returner combination is scheduled to have another orbital maneuver to escape lunar gravity and enter the moon-Earth transfer orbit to return to Earth.
Chang'e-5 is one of the most complicated and challenging missions in China's aerospace history. It is also the world's first moon-sample mission in more than 40 years.
The probe, comprising an orbiter, a lander, an ascender and a returner, was launched on Nov. 24, and its lander-ascender combination touched down on the north of the Mons Rumker in Oceanus Procellarum, also known as the Ocean of Storms, on the near side of the moon on Dec. 1.
The probe's returner is expected to land at the Siziwang Banner in north China's Inner Mongolia Autonomous Region in mid-December. ■