China's Space Program News Thread


taxiya

Colonel
Registered Member
Peacock experimental reusable rocket. It was apparently involved in testing new intelligent flight control software. Because my technical Chinese in this area is deficient, I'm not able to competently translate the text below. Our Chinese-speaking members, please help with a translation.

十二所智能飞行控制技术演示验证试验圆满成功】2020年9月27~28日,航天一院十二所完成了非程序制导控制技术飞行演示验证试验,取得圆满成功!本次试验验证了基于分布式感知的力载荷与弹性模态辨识、软硬件协同加速及多核并行的在线轨迹规划、姿态控制稳定裕度在线辨识与自适应控制等一系列关键技术。试验利用自研的重复使用平台——“孔雀”飞行器进行。此次试验是2020年十二所“一组突破”的第一项,提升了非程序制导控制理论与方法的技术成熟度,为全面实现“航天智控1.0”提供了重要支撑。
In short, you have get the essence of the article "intelligent flight control".

In full, here is the translation (in my best effort)
12th institute of 1st academy has completed a flight demonstration proof of concept "non-programmed guidance and control". The demonstration flight has verified series key technologies:
  1. force-load and flexible mode identification based on distributed sensors
  2. SW and HW coordinated accelerated multi-core parallel real-time route planning
  3. real-time identification of stability margin of position (orientation) control
  4. adaptive control
The demonstration uses self-developed (of course) reusable platform "peacock". This demonstration is the 1st item of "group breakthroughs" by 12th institute in 2020. It has improved the maturity of "non-programmed guidance control" in both theory and methodology. It serves as a important support (milestone, foundation) for fully realization of "Aerospace Intelligent Control 1.0".
The key point here is "non-programmed guidance and control". The Chinese words is "非程序制导控制". I could only find one doctoral dissertation that used 非程序制导控制 which is translated to "non-programmed guidance and control" in its English summary. The dissertation is about "guidance of boost and glide missile guidance".

Here is what I could gather by reading the paper
In programmed guidance system, the input target coordinate/location and current coordinate/location are used to plot a fixed route. Any deviation of the plot will trigger a minus or plus control command to turn the vehicle back on track. In pseudo code it looks like
if (off course to left by 1 degrees) then​
thruster push left by 10 Newton force​
It is called "programmed" because for every deviation scenario there is a predetermined adjustment action. A good example is C based language.

To be clear, "non-programmed" is still a computer program but not in the traditional sense. Non-programmed control is to set a set of constraints rather that predetermined If-Elses. The constraints are the expected parameters like route point, angel and speed etc, and of course the target location. The control system will work out all sort of control commands in real-time on the fly to make sure the vehicle stay with the constraints leading it to the target.

The key difference is the commands are generated on the fly rather than pre-loaded before the flight. A close example is the computer language Erlang which BTW will drive a new completely nuts.:D
 

ougoah

Captain
Registered Member
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Did someone say China needed a starlink-like constellation?
Things like Starlink constellations in LEO and whatnot truly are a backup military constellation and the associated launch capabilities that make a fast and numerous constellation possible. China sort of doesn't quite need such a thing as the US does. Why? Because China's military posture is very defensive and regional where they already have numerous types of very fast and extremely high altitude reconnaissance and communications drones that probably can perform many other duties tasked by satellites. Regional advantage means easier to deploy and continue deploying these drones as opposed to sending them and somehow fueling them halfway around the world like the US would need to do if their mainstay satellites are disabled. Regional wars also mean you don't quite have as much comprehensive need for these sorts of satellites for targeting, comms, and navigation.

Of course all of this progress is still very valuable because one never knows when certain technologies become useful in myriad of other unexpected ways. It still pays to start working on relatively pointless tools today when you have the time and money.
 

gelgoog

Senior Member
Registered Member
China already does more satellite launches than either the US or Russia. Their satellite networks are mostly global but they will tend to go global in due time much like what happened with Beidou. This without the new generation rockets being in full production even. Once they enter full production I expect China to increase its global coverage more.

PS: Do the Chinese have electric propulsion technology for satellites? That is one of the main technologies behind Starlink.
 

ougoah

Captain
Registered Member
China already does more satellite launches than either the US or Russia. Their satellite networks are mostly global but they will tend to go global in due time much like what happened with Beidou. This without the new generation rockets being in full production even. Once they enter full production I expect China to increase its global coverage more.

PS: Do the Chinese have electric propulsion technology for satellites? That is one of the main technologies behind Starlink.
But the important thing is the Starlink style projects are built on very impressive LEO launch technologies that are cheap, numerous, and effective. So China needs to also develop similar capabilities and accessibility which will be done but it's just yet another thing to give attention to.

China will need to bridge the widening gap in booster tech, rocket engines, and various forms of economical advantages. Re-usable is a a really good solution for SpaceX because their boosters, rockets, and engines are undoubtably very expensive whereas Chinese ones probably can achieve desired function at much lower costs, therefore making reusables a more questionable endeavor. But there are other ways to lower costs and reusable is definitely still going to be worth pursuing for Chinese launchers even if the benefits won't be as considerable compared to the benefits for US launchers.
 

gelgoog

Senior Member
Registered Member
China until quite recently used hypergolic rockets. Not something exactly easy to reuse. You need special suits and a special environment to refill a rocket like that. Their most recent engines and rockets however are more amenable to reuse. One of the private Chinese companies is developing rockets with a similar guidance profile to the Falcon 9 in terms of reuse back to land. I think it is a question of time until other nations start doing rocket reuse too. One example is Japan. The engine on their H-III rocket is really well suited for reuse, even more than SpaceX's. The H-III could be redesign into a reusable rocket if they wanted to. Thing is they do so few launches it will probably not be cost competitive to reuse. China does many launches so it will be profitable to reuse rockets.
 

taxiya

Colonel
Registered Member
PS: Do the Chinese have electric propulsion technology for satellites? That is one of the main technologies behind Starlink.
Yes, China has it for years, as early as 2014 on DFH-3B platform. The recent CZ-5 launch in 2019 was DFH-5 platform which also uses electric propulsion. If an earlier CZ-5 launch did not fail, DFH-5 would have been in orbit in 2017.
 

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