Author Topic: China's space program  (Read 668832 times)

Offline vjkane

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Re: China's space program
« Reply #380 on: 02/06/2014 03:29 pm »
I think China could do this, and if they did pull it off, it would be an impressive engineering achievement in robotic space exploration that nobody else has done.
It would be a stupendous achievement. 

If they couldn't do a rover, the work on the South Pole-Aitken Basin sample return for the New Frontiers program shows the value of grab samples form a well selected site.  In fact, if NASA doesn't select the Aitken Basin sample return in the next New Frontiers selection, China could easily do this with Chang'e 6 (presuming they want to put Chang'e 5 on the near side for continuous communications).  From the press reports, the missions will have an orbiter that could serve as a comm relay from the far side.

Online Blackstar

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Re: China's space program
« Reply #381 on: 02/06/2014 04:14 pm »
If they couldn't do a rover, the work on the South Pole-Aitken Basin sample return for the New Frontiers program shows the value of grab samples form a well selected site.  In fact, if NASA doesn't select the Aitken Basin sample return in the next New Frontiers selection, China could easily do this with Chang'e 6 (presuming they want to put Chang'e 5 on the near side for continuous communications).  From the press reports, the missions will have an orbiter that could serve as a comm relay from the far side.

Well, the MoonRise work at JPL for SPAB sample return is more than simply "grab" sampling. The arm has a kind of backhoe on it, scoops up material (cutting down into the surface) and deposits that in a sifter that takes out the small dust and the bigger pieces, getting the size material that they want. JPL did a lot of work to demonstrate that the collector would work, the sifter would work, and that they can then put the sample container into the ascent vehicle. I don't think that any of this work is particularly hard engineering, but you do want to get a sense that it will work before you build the equipment for your lander.

Now going through a relay orbiter adds complexity, because you only have limited windows for comm. It would require a certain amount of automation on the lander so that you use the comm windows for updates and to correct issues. But you're right that if China is designing a system that already has an orbiter, then they're already far along the path toward developing the capability to use it as a relay.

The NASA SPAB New Frontiers mission is not a particularly difficult mission. It is difficult to keep within a New Frontiers cost cap, but the engineering is straightforward. I am reminded once again of the fact that China has a working lunar lander and the United States has a bunch of lunar landing studies and some test hardware. If China wanted to do that South Pole Aitken Basin sample return mission (and they are willing to spend the money), they could do it, no question.

Offline Steven Pietrobon

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Re: China's space program
« Reply #382 on: 02/07/2014 03:35 am »
Bit surprised here too.  Chang'e 1 was a success, but followed up by Chang'e 2 with a more ambitious mission profile.  the same pattern can be seen in their crewed missions also.

I has asked the Chinese delegate this. Chang'e 2 was not considered the same as Chang'e 1, as it demonstrated the mission profile to be used on later missions.

I met with the China Manned Space Agency (CMSA) delegate again yesterday who works in the International Cooperation Bureau. Here are some answers I got from him. Again, this is from memory, so it may contain errors.

The modular space station will be three modules like that shown previously. There will be a main module and two side modules with solar panels on the end. The design is currently being finalised. Each side module will first dock with the front axial port. Then a robotic arm (not as big as the ISS arm) will transfer the module to a side docking port. The docking mechanism will be closer to the Russian design and won't be compatible with the International Docking Standard (IDS). The Chinese have looked at IDS and consider it to be something they could build.

The CMSA is currently in discussion with ESA in three main areas. 1) Flying ESA astronauts to the station, 2) Providing either an ATV for supplies or a module and 3) providing experiments. They have visited Canada and looked at their arm technology, but won't be using a Canadian arm. The Italians showed the Chinese their Cupola, but they won't be using this initially. Maybe at a later date. The Swiss are looking to provide an astronomical payload.

Tian Gong 2 is planned for a launch in 2015 and the supply module in 2016. The supply module will be closer in design to Tian Gong. To communicate with Tian Gong 1, the Chinese contracted a Swedish company to install a dish near Perth in Western Australia.

The delegate was disappointed that there were no representatives from any space agencies at the International Space University Southern Hemisphere Summer Space Program (SHSSP). I have the delegate's business card, so if you are from a space agency and would like to cooperate in their manned space program, please contact me by email and I will pass on his details.

He also said that he would be happy to answer any questions I have about their manned program. He said it may take a few days to get a reply using his email address though.

The SHSSP closing ceremony is this afternoon. The next session is expected to be in South Africa in one years time, but this has not yet been finalised.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline Lsquirrel

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Re: China's space program
« Reply #383 on: 02/07/2014 08:11 am »
At the International Space University Southern Hemisphere Summer Space Program being held here in Adelaide there are quite a few students from China who work in the Chinese space program. I got to talking with the Chinese person responsible for international collaboration in their crewed space program. Some of the answers I got were the following. This is from memory, so there might be some mistakes.

Tian Gong 2 will have only one docking port. They consider Tian Gong to be more of a space lab, then a space station. The large modular space station will have a different name. The main purpose of Tian Gong 2 will be to test the docking and fuel transfer of a supply vehicle. Longer crewed missions are expected, perhaps from one to three months. They are considering having Tian Gong 2 crewed for the supply vehicle docking, but there are safety risks involved as Shenzhou can't be docked at the same time.

For Shenzhou 10 last year there was a lot of discussion as to whether to fly the mission. They are happy they did so, as they learnt quite a few things.

If Chang'e 3 is successful, they won't fly Chang'e 4.

A decision for a Lunar crewed program won't be made until after the modular station has been built and been operating for a number of years. Perhaps a decision will be made in 2025 or 2030.

The European astronauts are learning Chinese. International astronauts are expected for the modular space station.

According to Chang'e-1 Chief Designer Ye Pei Jian,Chang'e 4 will be launched in 2015,while a skip reentry demo probe will be launched in 2014.
the skip reentry experiment  will be a pathfinder of Chang'e-5.

Offline Lsquirrel

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Re: China's space program
« Reply #384 on: 02/07/2014 08:24 am »

1-Surprising that they were not expecting to fly CE-4 no matter what. You'd think that they would want the experience. The more wheel turns that they can get on any planetary body, the better. Rover experience would set them up for an eventual Mars rover. With Yutu possibly out of commission, I would expect them to fly CE-4.



Bit surprised here too.  Chang'e 1 was a success, but followed up by Chang'e 2 with a more ambitious mission profile.  the same pattern can be seen in their crewed missions also.

I would have thought that Chang'e 4 would at least go somewhere different, such as the highlands or even the poles, given that Chang'e 3 landed from what appears to have been a polar orbit.

Another rover is worth doing for its' own sake as well as providing experience that could be used for Mars and further confidence in the lander for the sample return missions. 


Not to mention that it could form the basis for an interesting joint mission. One clever approach would be this:

-hold CE-4 (and its rover) in reserve
-fly CE-5 as a sample return mission

If CE-5 is successful, then reorient and redesign CE-6. Instead of having CE-6 take a sample at the landing site, have CE-6 land, then land CE-4 nearby, use the rover to scoop up material and deliver it to CE-6 for return to Earth.

That's the kind of thing that NASA is considering for Mars 2020 and Mars sample return. It would be an interesting and challenging mission for China to do on the Moon, but it would actually be a logical progression if they had success with CE-3 and CE-5.

Now I still think that the safe and wise engineering approach (no matter if CE-3 is a success or not) is to land CE-4 and operate it as much as possible and as long at possible. Get as many wheel turns as possible to understand that environment. But the scenario I outlined above would be both an engineering/operations challenge and scientifically productive. And it would do something that neither the US or Soviet Union has done before, using a rover to collect materials for sample return.

Using a Rover to collect materials is too ambitious to chinese engineer, so we have choosen a less challenge mission, using a Lander to dig luna soil, which will be found in Chang'e-4
« Last Edit: 02/07/2014 08:34 am by Lsquirrel »

Offline baldusi

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Re: China's space program
« Reply #385 on: 02/07/2014 10:51 am »
Steven, was any CONAE representative around?

Offline Lsquirrel

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Re: China's space program
« Reply #386 on: 02/07/2014 12:21 pm »
Thanks for the useful news, Steven - good work!

ESA and CNSA are indeed actively cooperating in the area of astronaut training. There have been reciprocal astronaut visits to training facilities.

Are any of the presentations being posted online, do you know, or can you obtain copies of them?

Can you find out anything more about the architecture of the modular space station? Do the Chinese expect each module to bring its own power supply, or will they provide a centralised power supply like the ISS USOS? How serious are the images of the station that have appeared online so far?

We hear a lot about international cooperation in the Chinese space station program but is anything really happening? Could you find out if the Chinese are planning a series of symposia to discuss international proposals for participation in the modular space station program?

By the way, following their success with Chang'e the Chinese are now taking an active role in ISECG discussions. The next ISECG meeting is planned for May in Beijing.

I have download some presentions:


Offline baldusi

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Re: China's space program
« Reply #387 on: 02/07/2014 01:22 pm »
Thank you for those presentations! I've a few questions:
1) They talk about international cooperation and rescue ops, but they won't move the orbital plane from ~42deg. This basically leaves out Russian launchers and crafts (Progress might work from CSG, but Soyuz can't). And the plane change makes it inaccessible to the ISS. So the Russians can't launch a Soyuz to rescue the Chinese, and only the Chinese could launch to the ISS. But they've stated that they won't be IDSS compliant. So, much talk about possibilities but the technical decisions speak differently.
2) They stated that the zenith and nadir ports of the node are reserved for international modules, but then they show the nadir port used during hand-off. And it would only make sense that they would want at least a spare docking port for all manned operations, which would imply at least 3 ports dedicated to manned docking.
3) Btw, the pictures describe the Robotic Arm 1 on the Zenit port of Node. Will it be able to move a module docked on Aft(?) to the Nadir port?
4) I see the Lab 1 will have an airlock. Will the Shenzhou orbital module be used as a contingency EVA port?
5) The Robotic Arm 2 on Lab 1 is to deploy experiments from the local airlock? Am I to assume that it will host the external experiments attachments?
6) Is it being designed with only contingency EVAs in mind? I find the lack of actual EVA experience in the manned program quite puzzling.
7) Am I correct in understanding, since they said that the space station projects was "approved" only by 2010, that when they mean "approved" they mean something like authorizing the actual project, and not about preliminary designs or experiments?

Online Blackstar

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Re: China's space program
« Reply #388 on: 02/07/2014 08:57 pm »
Using a Rover to collect materials is too ambitious to chinese engineer, so we have choosen a less challenge mission, using a Lander to dig luna soil, which will be found in Chang'e-4

My point was that if they have a successful CE-5 mission, using a lander to dig and return lunar soil, then a logical step would be to use a rover to dig up soil and take it to CE-6. You could have a logical development building on the success of each mission.

My guess is that China will now fly CE-4 with a rover to try and get experience because they did not have a fully successful CE-3. But the sequence I proposed seems to me to be within China's capabilities. China has already done the hard things: landing a vehicle, deploying a rover. The next hard thing to do is sample return and orbital rendezvous. But some of the rendezvous technology has already been developed in Earth orbit.

Offline Dalhousie

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Re: China's space program
« Reply #389 on: 02/07/2014 11:02 pm »
To justify a sample collection rover you will need a reasonable traverse capability to be able to sample different units, probably at least 10 km, and of course to drive to the sample return system.
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I also wonder at the mass of the sample collection mechanism and the storage system.  Yutu is a fairly small rover.  They could leave off the GPR perhaps.
Apologies in advance for any lack of civility - it's unintended

Offline MATTBLAK

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Re: China's space program
« Reply #390 on: 02/07/2014 11:10 pm »
I've said it before and I'll say it again - I'm full of admiration for their efforts. GO CHINA!! :)
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Online Blackstar

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Re: China's space program
« Reply #391 on: 02/07/2014 11:12 pm »
To justify a sample collection rover you will need a reasonable traverse capability to be able to sample different units, probably at least 10 km, and of course to drive to the sample return system.

Not really. A rover is just a way of moving around your instruments. Ideally you want to be able to move them far, but one thing that bothered the Viking scientists in the 1970s was that they could see interesting rocks just a few meters away and could not reach them. A rover allows you to travel to the interesting stuff. Hopefully you have already landed near the interesting stuff.

Offline vjkane

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Re: China's space program
« Reply #392 on: 02/07/2014 11:35 pm »
An operationally simpler method would be for the sample return lander to bring the rover with it.  Chang'e 5 might just use a scoop while Chang'e 6 might also carry a small rover.

I suspect, though, that these design decisions with mass allocations have already been made.

I have worried about the lack of a small rover on the proposed New Frontiers sample return missions for the reasons Blackstar mentions.   

Offline Dalhousie

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Re: China's space program
« Reply #393 on: 02/08/2014 01:36 am »
To justify a sample collection rover you will need a reasonable traverse capability to be able to sample different units, probably at least 10 km, and of course to drive to the sample return system.

Not really. A rover is just a way of moving around your instruments. Ideally you want to be able to move them far, but one thing that bothered the Viking scientists in the 1970s was that they could see interesting rocks just a few meters away and could not reach them. A rover allows you to travel to the interesting stuff. Hopefully you have already landed near the interesting stuff.

The Moon is different though.  Run a sieve through the regolith and you will get a representative sampling of the local bedrock and a proportion (~10% from memory) of more distant material as well.  For for example samples of mare regolith will contain fragments of highland crust from 100s of km away.  This is through impact gardening, which is why geological boundaries are smeared out over 100 m of more, and why actual outcrop is very rare.

The combined sieve and scoop is conceptually a descendent of the rake used on Apollo 15-17 http://airandspace.si.edu/collections/artifact.cfm?object=nasm_A19781497000

I suspect that the Viking scientists had a conceptual model for the martian regolith that was essentially lunar when they designed their sampling system.   Not unreasonable, given the Moon like concepts of the martian surface prevalent when the hardware was being designed. But the only rocks within reach of both Vikings turned out to be indurated soils. Impact gardening does not happen on Mars to anywhere near the same extent due to higher gravity, lower small impact cratering rates, and higher erosion and weathering rates. 

Apologies in advance for any lack of civility - it's unintended

Offline Steven Pietrobon

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Re: China's space program
« Reply #394 on: 02/08/2014 02:10 am »
Steven, was any CONAE representative around?

No. There was one person from Brazil.
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Online Blackstar

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Re: China's space program
« Reply #395 on: 02/08/2014 02:21 am »
1-An operationally simpler method would be for the sample return lander to bring the rover with it.  Chang'e 5 might just use a scoop while Chang'e 6 might also carry a small rover.

I suspect, though, that these design decisions with mass allocations have already been made.

2-I have worried about the lack of a small rover on the proposed New Frontiers sample return missions for the reasons Blackstar mentions.   

1-Yes.

2-JPL has evaluated the possibility of the AXEL rover on their MoonRise proposal. When I talked to the MoonRise PI he did not think it was included, and it is certainly not necessary from a mission point of view. However, the JPL program manager indicated that they had mass budget to carry one. And the company that does sampling devices (I think it is Honeybee?) has actually tested a small sampler for AXEL. It is a little short drill that pokes out of the side of the wheel and gathers a small sample. Of course, getting that back to the sample canister is going to pose some design challenges. But I don't really think it is necessary, at least not for the SPAB mission. I think JPL has only included provisions in case somebody gives them a thumbs up and can come up with a good reason for it.

Personally, if a SPAB lander had extra mass, I would rather see it carry a seismometer, but that would probably make little sense because the SPAB mission only has to operate for a short period of time, whereas a seismometer requires a long-term power source, and that would completely change the mission.

Offline plutogno

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Re: China's space program
« Reply #396 on: 02/08/2014 07:13 am »
the latest issue of Scientia Sinica Technologica has several technical papers in Chinese on rendezvous and docking techniques as well as a paper on the use of finite elements for launch vehicle structural dynamics

http://tech.scichina.com:8082/sciE/CN/volumn/volumn_6804.shtml

Offline plutogno

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Re: China's space program
« Reply #397 on: 02/10/2014 07:42 am »
it looks like the Chinese are seriously thinking about a comet flyby mission to Wirtanen in 2018. this was proposed by Richard Farquhar at the latest IAC as a joint US-China mission, where the US would contribute the old ICE spacecraft. whether this kind of cooperation was really possible is not clear, but in any case it looks like NASA no longer has the hardware to communicate with the probe.

http://www.dost.moe.edu.cn/dostplan/jyjl/20130816155543

Google translation:
Quote
  6. Sino-US joint deep space exploration - comet "Wo Tanan" exploration program
    Project Source: Collaborative units to implement the project.
    Total funding: 2.5 million.
    The key breakthroughs in core technologies proposed: deep space exploration technology in general, autonomous navigation and control technology, deep space communications and control technology, efficient energy and propulsion technology, advanced load technology.

Offline vjkane

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Re: China's space program
« Reply #398 on: 02/10/2014 02:17 pm »
6. Sino-US joint deep space exploration - comet "Wo Tanan" exploration program
 

I've not heard anything about a US mission to this comet.  Has anyone else?

Offline plutogno

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Re: China's space program
« Reply #399 on: 02/10/2014 02:22 pm »
I've not heard anything about a US mission to this comet.  Has anyone else?

it was a mission proposed a year ago by Robert Farquhar. China would provide a flyby craft, while the US would retarget ICE to fly through the tail of the comet.
see http://www.bis-space.com/2012/11/29/7813/bis-prestige-lecture-teaching-old-spacecraft-new-tricks and this paper: http://www.iafastro.net/iac/paper/id/16371/summary.lite/

 

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