China's Space Program News Thread

[eprash]

I highly doubt that even in the west there is a separate technology path and supply chain for solid propellant. Correct me if I am wrong, all solid boosters in commercial launches in the world are continuation of missile programs, meaning except the dimension and avionic, the propellant is the same either in a missile or a civilian launcher.

So far in China there is no civilian manufacture making exclusive civilian booster propellant. All of them are producers that solely serve the military until recent, and begin to do civilian business, so there is no separata tech/production chain in China at least.

It used to be the case but these days it's different, Missile propellants are the best the State's chemical industry can deliver whereas Launch vehicle propellants are the cheapest option that won't blow up in your face while meeting program objectives, hope i made it clear

 

[taxiya]

No idea what the MX uses (I'm not terribly interested in American military technology), but if it isn't NEPE then I assume it's APCP.

As I understand it, the DF-41 uses NEPE in all stages, while the DF-31 has a NEPE upper stage and APCP first and second stages (like the MX, supposedly).

The article that I sourced mentioned "DF-NG" which may be DF-41 or may be DF-41 successor. In the article it says N-15 (NEPE equivalent) is used only on 3rd stage. I guess for the same reason as MX. NEPE is energy denser, but more risky to handle. For SLBM there is no choice considering the restraint of space and mass. But for a land based missile, the restraint is less a problem, safety for long-term maintenance is preferable therefor the choice of APCP (or similar).

The same article also mentioned an underdeveloped N-15 variant which is cheaper and retarded that makes is suitable for long-term handling which may eventually replace APCP likes. When that happened, civilian boosters will also use it for its lower than N-15 price and better performance, again same supplier. The cost of that cheaper N-15 is 60% of "normal" N-15.

 

[taxiya]

It used to be the case but these days it's different, Missile propellants are the best the State's chemical industry can deliver whereas Launch vehicle propellants are the cheapest option that won't blow up in your face while meeting program objectives, hope i made it clear

see my other posts about ICBMs and commercial boosters using the same propellants.

 

[ZeEa5KPul]

The article that I sourced mentioned "DF-NG" which may be DF-41 or may be DF-41 successor. In the article it says N-15 (NEPE equivalent) is used only on 3rd stage. I guess for the same reason as MX. NEPE is energy denser, but more risky to handle. For SLBM there is no choice considering the restraint of space and mass. But for a land based missile, the restraint is less a problem, safety for long-term maintenance is preferable therefor the choice of APCP (or similar).

The source I got this from (whom I consider to be of the highest reliability) stated that the first and second use a slower-burning NEPE compound than the third stage.

The safety argument you've given doesn't make sense to me for two reasons: 1) NEPE is already used on the third stage and if a disaster happens then it'll certainly ignite the other stages no matter what compound they use. 2) Rockets are extremely sensitive to the performance of the fuel used (which determines the specific impulse of the motor). A 10% increase in specific impulse could nearly double the throw weight of the rocket. I don't know the difference between specific impulses of NEPE and APCP rockets, but that seems like a reasonable estimate for the improvement.

 

[clockwork]

The source I got this from (whom I consider to be of the highest reliability)

Was this I_H8_Y8s again? I'd like a link if possible (i.e. wasn't a PM).

Also this isn't really the right thread but what's the consensus here at this point for the missile to fill the silos, DF-41 or 45?

 

[ZeEa5KPul]

Was this I_H8_Y8s again? I'd like a link if possible (i.e. wasn't a PM).

Also this isn't really the right thread but what's the consensus here at this point for the missile to fill the silos, DF-41 or 45?

Yes and it was via PM.

I don't know that there is a consensus on how the silo fields will be employed in the near and longer term. The silos themselves are sized quite generously - they can accommodate a much larger missile than the DF-41. When this supposed "DF-45" will appear and what its specifications are isn't known. My own bet is that the fields will employ DF-41s in a "shell game" initially, and we'll see where things go from there.

 

[AndrewS]

The article that I sourced mentioned "DF-NG" which may be DF-41 or may be DF-41 successor. In the article it says N-15 (NEPE equivalent) is used only on 3rd stage. I guess for the same reason as MX. NEPE is energy denser, but more risky to handle. For SLBM there is no choice considering the restraint of space and mass. But for a land based missile, the restraint is less a problem, safety for long-term maintenance is preferable therefor the choice of APCP (or similar).

The same article also mentioned an underdeveloped N-15 variant which is cheaper and retarded that makes is suitable for long-term handling which may eventually replace APCP likes. When that happened, civilian boosters will also use it for its lower than N-15 price and better performance, again same supplier. The cost of that cheaper N-15 is 60% of "normal" N-15.

Civilians will not be using solid-fuel boosters in large numbers. It simply is not competitive with liquid-fuelled rockets.

Civilian use of solid-fuel boosters is simply a stepping stone for companies to gain some launch expertise before moving to liquid-fuelled

 

[AndrewS]

From what I can see, it currently costs SpaceX about $1000 to send 1 kg to Low Earth Orbit using the Falcon 9 Full Thrust

That is far below anything anyone else can manage and is the current benchmark to beat

And looking at the Starship design with a reusable 2nd stage, they should be able to get this down to $100 per kg to Low Earth Orbit.
That is 10x less

---

Looking at Galactic Energy, Landspace and i-Space - their current engines should be comparable to the Merlin engines on the Falcon 9

But both SpaceX and Blue Origin are developing rockets which are far larger than the Falcon 9, along with much larger engines, like the Starship which aims for 10x lower costs

I reckon the Chinese rocket startups will end up developing reusable designs comparable to the Falcon 9 in the next 2 years.
But this will only be an intermediate step before they have to go with:

1. A new Methane-Oxygen1st Stage Engine design which is much larger
2. A larger 1st Stage Rocket design
3. Reusable 2nd stage

 

[nixdorf]

From what I can see, it currently costs SpaceX about $1000 to send 1 kg to Low Earth Orbit using the Falcon 9 Full Thrust

That is far below anything anyone else can manage and is the current benchmark to beat

And looking at the Starship design with a reusable 2nd stage, they should be able to get this down to $100 per kg to Low Earth Orbit.
That is 10x less

---

Looking at Galactic Energy, Landspace and i-Space - their current engines should be comparable to the Merlin engines on the Falcon 9

But both SpaceX and Blue Origin are developing rockets which are far larger than the Falcon 9, along with much larger engines, like the Starship which aims for 10x lower costs

I reckon the Chinese rocket startups will end up developing reusable designs comparable to the Falcon 9 in the next 2 years.
But this will only be an intermediate step before they have to go with:

1. A new Methane-Oxygen1st Stage Engine design which is much larger
2. A larger 1st Stage Rocket design
3. Reusable 2nd stage

 

[taxiya]

The source I got this from (whom I consider to be of the highest reliability) stated that the first and second use a slower-burning NEPE compound than the third stage.

I am almost certain that your source was talking about the DF-41 successor or new silo based missile which is the "DF-NG, DF-51, DF-45" or whatever name it maybe that was under development before 2010, but may have finished today.

There were two papers. 1. 二十一世纪航天科学技术发展与前景高峰论坛暨中国宇航学会第二届学术年会论文集 published in 2007. The conference was held in 2006. 2. N15类高能低特征推进剂在战术导弹发动机上的应用研究 published in 2005. Since their date matches closely I believe they can be support one another. So I will list my points based on both of them.

1. There is a conceptual design of advanced solid motor whose 1st stage is HTPB. 2nd stage being either N-15/N-15B or HTPB. 3rd stage being another type of unnamed high energy propellant.
2. N-15 was used by strategic missile at the time. But the publication did not say all stages.
3. N-15B is equally energy dense as N-15 but cheaper. It was under testing.
4. The publication said "N-15B may be an option for future large solid motor".
5. The unnamed propellant has 5% higher specific impulse than N-15. It will be used for 3rd stage for future strategic missile.
6. N-15B is more retarded which was quoted as the other reason for its development besides being cheaper.

Point 1 is essentially saying that the then under-developing strategic missile is similar to MX using HTPB for 1st stage and maybe 2nd stage as well. This also agrees with point 2 as N-15 being used but not the whole missile.

Point 3 is probably about the then future missile aka DF-XX/45/51/NG. This missile may use yet another type of propellant for its 3rd stage as point 4.

N-15 is not to be used for all stages may be due to its higher price, or maybe due to its less ideal (than HTPB) handling property. We can never know for sure. If NEPE was so ideal, I would have expected that MX' being gradually refreshed with NEPE. But that we probably will never know.

All I have been saying is that, at least for China, all sorts of propellant and solid motors are made by same suppliers. There is not much division between military and civilian applications in terms of technology or producer, the only consideration is price, which is equally considered in missile and rocket launcher.

As of why some people have the idea that HTPB/APCP are better for civilian application (basically taking the cue from US example), I dare to say that if US is confident in NEPE and its price tag allows, US would have switched to full NEPE for SRBs. Not switching may be simply that they don't have their cheaper version of NEPE, the N-15B equivalent, nor do they have the volume of order to warrant the switching even if it is feasible.

I will stop here now as it is getting off topic.