China's Space Program News Thread

[gelgoog]

Combustion chamber of third stage engine for CZ-9 (11) was tested. The engine is 25 tonne force thrust, expander cycle. Two tests were done at 60% and 100% thrust. The tests did not involve the expansion of LH and LO, only the combustion chamber. LH and LO were fed by compression. It is ready for full system test.

There is a statement "该型发动机是目前世界推力最大的膨胀循环氢氧上面级发动机"/This engine has the highest thrust among expander cycle. I know why it is claimed to be so. Just curious if anyone is going to reject that on what definition.

Heh. The Japanese LE-9 first stage expander bleed cycle rocket engine used in the H-3 rocket has 1471 kN thrust.
AFAIK that is the largest expander cycle engine ever made. To the point some even wondered if it was possible to design at the time.
There are issues with physics which limit the maximum possible size of an expander cycle engine and this one should be close to the limit.

The second stage of the H-3 rocket uses the LE-5B-2 expander bleed cycle engine with 145 kN thrust.
This engine, the YF-79, has 243 kN thrust and is a closed expander cycle engine.
The French designed Vinci expander cycle engine has 180 kN thrust.

So yes it should be the largest last stage expander cycle engine in use when it comes out. But not the largest expander cycle engine ever.
The US/Japan did have plans to make a similar rated engine in the 1990s, the RL-60, but it got cancelled about when the SLI got cancelled.
Vinci and LE-5B-2 have both completed their development stage. The LE-5B-2 is in current use.

Why wait 8 years if all critical technologies have been tested? Why not have the maiden flight in five years ?

They are still testing the combustion chamber. That is where the high pressure turbulent burning of fuel happens. If it doesn't work properly the engine can explode. Getting it to work is a significant milestone. But you still need to design the engine nozzle, do vacuum testing, design the engine control unit, etc.

 

[gadgetcool5]

There have been four consecutive successful launches of the Long March 7/7A series of rockets this year, compared to only two successful launches (and one failure) in the entire previous five years since the rocket's debut. It seems like the Long March 7/7A has really come into its own this year, similar to how the Long March 5/5B did last year. Hopefully in the future it can replace the Long March 3B and the Long March 2F for manned missions.

 

[Blitzo]

It seems to me that all critical technologies of CZ-9(11) have been tested. All engines have passed critical stages. With 8 years ahead, CZ-9(11)'s maiden flight before 2030 is almost certain.

How far are they along development with CZ-9(11) do you think they would have to go for it to be considered so far along that it is not worth it to cancel it?

At present I can see a rationale for working on both CZ-9(11) and (21), but at a certain point in the next couple of years I imagine they'll have to choose between one or the other, and given the noises they've made about 2030s and 2040s launch requirements in terms of frequency and tonnage, I have a feeling they're going to end up with a resuable super heavy first stage that looks something like (21) eventually.

===

Please, Log in or Register to view URLs content!

From 2020, a prospective goal of seeking to be able to conduct a hundred per year around 2035 with the ability to annually launch thousands of tons into orbit, and in 2045 to conduct on demand launches of a thousand launches per year with the ability to launch tens of thousands of tons into orbit a year.

　　包为民当天在福州开幕的2020年中国航天大会上，作《航班化航天运输系统的发展与思考》演讲时透露了上述计划。他说，实现航班化航天运输目标分为三个阶段：2025年前为起步建设阶段，主要任务是突破关键技术，形成试验试用系统；2035年实现目标初步建成，年总飞行数百次、总货运千吨级、总客运千人次；到2045年目标全面建成，实现按需发射，每年总飞行次数达千次量级，总货运万吨级，总客运万人次。

 

[tiancai8888]

How far are they along development with CZ-9(11) do you think they would have to go for it to be considered so far along that it is not worth it to cancel it?

At present I can see a rationale for working on both CZ-9(11) and (21), but at a certain point in the next couple of years I imagine they'll have to choose between one or the other, and given the noises they've made about 2030s and 2040s launch requirements in terms of frequency and tonnage, I have a feeling they're going to end up with a resuable super heavy first stage that looks something like (21) eventually.

===

Please, Log in or Register to view URLs content!

From 2020, a prospective goal of seeking to be able to conduct a hundred per year around 2035 with the ability to annually launch thousands of tons into orbit, and in 2045 to conduct on demand launches of a thousand launches per year with the ability to launch tens of thousands of tons into orbit a year.

　　包为民当天在福州开幕的2020年中国航天大会上，作《航班化航天运输系统的发展与思考》演讲时透露了上述计划。他说，实现航班化航天运输目标分为三个阶段：2025年前为起步建设阶段，主要任务是突破关键技术，形成试验试用系统；2035年实现目标初步建成，年总飞行数百次、总货运千吨级、总客运千人次；到2045年目标全面建成，实现按需发射，每年总飞行次数达千次量级，总货运万吨级，总客运万人次。

It took 16 years for CZ-5 from approving the project to maiden flight. 12 years for YF-100 engine. We can expect CNSA to go faster but IMO 8 years is still a highly optimistic estimate.

For 921 it has its position in the LM family. Most techs to make 921 are on the shelf. More likely it will become new CZ-5. So that's way Long lehao gave it a name called CZ-5DY

And don't forget the Space Planes to meet the payload goal

 

[tiancai8888]

It took 16 years for CZ-5 from approving the project to maiden flight. 12 years for YF-100 engine. We can expect CNSA to go faster but IMO 8 years is still a highly optimistic estimate.

For 921 it has its position in the LM family. Most techs to make 921 are on the shelf. More likely it will become new CZ-5. So that's way Long lehao gave it a name called CZ-5DY

And don't forget the Space Planes to meet the payload goal

I misinterpreted the (21) as 921. The YF-135 engine now only be seen in powerpoint/paper. Apperently, now the 11 version of CZ-9 has more progress.

 

[Quickie]

It took 16 years for CZ-5 from approving the project to maiden flight. 12 years for YF-100 engine. We can expect CNSA to go faster but IMO 8 years is still a highly optimistic estimate.

For 921 it has its position in the LM family. Most techs to make 921 are on the shelf. More likely it will become new CZ-5. So that's way Long lehao gave it a name called CZ-5DY

And don't forget the Space Planes to meet the payload goal

I think CZ-9(21) is not 921. The former has a core diameter of 10m, the latter 5m.

Edit: Just saw your correction.

 

[by78]

Chang'E lander has been in operation on the lunar surface for 100 months.

 

[by78]

High-resolution images of the latest CZ-7A launch mission.

 

[by78]

 

[by78]