China's Space Program News Thread


Orthan

Junior Member
Apparently other people want to get a laugh and you are bothered. If NASA is that great, why they need Russia for that many years?

You cant compare the two situations. Back in the day, russia was a great space power, not so much now. But regarding china, i have already replied to that.
 

gelgoog

Senior Member
Registered Member
I guess by offshoot and fast-track you meant alternative. And your understanding is a two step approach, first 921 multiple launches to put man on the moon, followed by larger scale landing using CZ-9. My answer is, maybe or maybe not. So far I have not seen any paper suggesting this is the case.

Here is some background information.

In a paper by Long Lehao (2010), there was two phases to land man on the moon. Phase one is multiple launches without CZ-9. Phase two is crew rocket plus CZ-9. In one of the alternatives of phase one, there was even CZ-2F crew rocket involved, with two CZ-5s being the cargo rockets. Phase two is CZ-5DY crew plus CZ-9 cargo. This is the paper I have read years ago. All these plans require earth orbit rendezvous (EOR).

However another paper (2009), EOR was deemed too complicated and risk of total mission failure is too high due to the earth orbit waiting and docking. This paper basically made the same conclusion as Apollo which also proposed and killed the idea of EOR. This is why I kept objecting the idea of multiple launches of smaller rockets in place of CZ-9 class.

It is worth to note that Long Lehao's paper is about the overall idea of moon mission, not in detailed study of various approach. The 2009 paper is the outcome of sub-study into details. So it should be taken more seriously.

I believe that based on the study of this paper, CNSA has committed to LOR (lunar Orbit Rendezous) which Apollo used. But there is a difference. Aopllo's LOR is only about the docking of ascent stage and the returning modules, one LOR. CNSA's plan has the docking of crew with the landing combo before the landing, two LOR. CNSA's approach will significantly increase the total mass to TLI 75t or more, compared to APOLLO's 50t.

In this new approach, CZ-5DY was deemed two light to send crew module to lunar orbit, so it is replaced by 921.

Both papers have envisioned both small scale and large scale landing. However it is worth noting the conclusion of the 2009 paper.
View attachment 65971
It says "we can conduct small scale (4 or 3 launches), OR go straight to large scale (2 launches, crew + cargo)."

It seems that by that time in 2009, both approaches are on the table, but there is no decision of having the small scale as first step. It could be a large scale as the first step too.

Regardless which approach, 921 is not alternative to CZ-9, it is the crew carrier which may act as a cargo carrier in place of CZ-9 IF 921 is much faster in progress than CZ-9. However, I doubt it will be faster enough to warrant a small scale approach, we are looking at between 2025(921 earliest) and 2030 (CZ-9). Considering 921 is manned rocket, it will need multiple un-crewed launches (3 to 4) before sending man to the moon, that will put its earliest manned mission to 2028.

One the one hand, 921 can be seen as a fast-track alternative before CZ-9 is ready, or we can equally say that "multiple 921 launches" is a backup in case of CZ-9 delay.

Well, with a single launch site you will need to wait for an orbit with a multiple-launch architecture yes.
But if you have multiple launch sites like SpaceX does, one in Texas, and the other in Florida, you can possibly make it in the same orbit. It requires precise timing but it would be possible. You launch the Falcon Heavy rocket first with the equipment, then you launch a regular Falcon rocket with the crew, you dock them on-orbit then do the mission. Then that would do an Apollo profile landing mission.

A single Falcon Heavy can also launch a crewed capsule on a manned lunar flyby just by itself. I mean even Proton can do it and it has less launch capability. Also, making a bugbear out of Earth docking is silly. I mean the Chinese expect to build an Earth orbit space station right? If docking is that unreliable you couldn't even have a space station to begin with.

If you need a large delivered payload to the Moon proper you can either refuel the payload in orbit to increase delivered mass, or you use automated missions to deliver the larger payloads *ahead* of the human mission, or both. Without humans you can use all sorts of slow-moving but highly efficient propulsion systems to deliver the requisite payload instead. You could use solar-thermal or solar-electric propulsion for example. Solar-thermal with LH2 has like twice the ISP of a LOX/LH2 stage and is kind of simple to implement. It works more or less like a solar water heater but you heat LH2 and vent it out. You have increased ISP with those methods because part of the propulsion momentum comes from solar power and doesn't need to be carried as mass.

Unfortunately the past NASA leadership lacked a clear vision to implement a lot of these ideas. But right now, I think, if SLS gets cancelled eventually which is highly likely, then NASA will have the huge funds to design all sorts of Moon/Mars architectures different than the one outlined in the Vision for Space Exploration (VSE) made by Mike Griffin back when George W. Bush was President. They are already funding a lot of projects under the NASA Gateway project which is a manned space station orbiting the Moon.
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If you read the NASA plans for lunar exploration back from when Goldin was President of NASA you will see they had a much different idea of how to do a launch architecture compared to that of Mike Griffin's time. Mike Griffin designed an architecture which assumed no new technology had to be developed at all, even if the technology to be developed was trivial, so NASA ended up with a design which uses the SSME as an expendable main engine for example. Which is just silly.

The Chinese CZ-9 at least uses expendable main engines. But it is still a huge rocket which will likely require new larger construction buildings to make the sections of the rocket (NASA at least had the Michoud facility in Louisiana which built the Saturn V/Shuttle), together with the cranes to move them, the machines to weld them, larger barges to carry them to the launch site, new launch site, new test stands, etc. For a rocket you will likely launch one every two years and which disentegrates into launch. Hugely expensive.
 

by78

Brigadier
ExPace has successfully completed the first 'hot' test run of its LOX/LCH4 (Liquid Oxygen/Liquid Methane) engine.


 

taxiya

Colonel
Registered Member
Well, with a single launch site you will need to wait for an orbit with a multiple-launch architecture yes.
But if you have multiple launch sites like SpaceX does, one in Texas, and the other in Florida, you can possibly make it in the same orbit. It requires precise timing but it would be possible. You launch the Falcon Heavy rocket first with the equipment, then you launch a regular Falcon rocket with the crew, you dock them on-orbit then do the mission. Then that would do an Apollo profile landing mission.

A single Falcon Heavy can also launch a crewed capsule on a manned lunar flyby just by itself. I mean even Proton can do it and it has less launch capability. Also, making a bugbear out of Earth docking is silly. I mean the Chinese expect to build an Earth orbit space station right? If docking is that unreliable you couldn't even have a space station to begin with.

If you need a large delivered payload to the Moon proper you can either refuel the payload in orbit to increase delivered mass, or you use automated missions to deliver the larger payloads *ahead* of the human mission, or both. Without humans you can use all sorts of slow-moving but highly efficient propulsion systems to deliver the requisite payload instead. You could use solar-thermal or solar-electric propulsion for example. Solar-thermal with LH2 has like twice the ISP of a LOX/LH2 stage and is kind of simple to implement. It works more or less like a solar water heater but you heat LH2 and vent it out. You have increased ISP with those methods because part of the propulsion momentum comes from solar power and doesn't need to be carried as mass.

Unfortunately the past NASA leadership lacked a clear vision to implement a lot of these ideas. But right now, I think, if SLS gets cancelled eventually which is highly likely, then NASA will have the huge funds to design all sorts of Moon/Mars architectures different than the one outlined in the Vision for Space Exploration (VSE) made by Mike Griffin back when George W. Bush was President. They are already funding a lot of projects under the NASA Gateway project which is a manned space station orbiting the Moon.
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If you read the NASA plans for lunar exploration back from when Goldin was President of NASA you will see they had a much different idea of how to do a launch architecture compared to that of Mike Griffin's time. Mike Griffin designed an architecture which assumed no new technology had to be developed at all, even if the technology to be developed was trivial, so NASA ended up with a design which uses the SSME as an expendable main engine for example. Which is just silly.

The Chinese CZ-9 at least uses expendable main engines. But it is still a huge rocket which will likely require new larger construction buildings to make the sections of the rocket (NASA at least had the Michoud facility in Louisiana which built the Saturn V/Shuttle), together with the cranes to move them, the machines to weld them, larger barges to carry them to the launch site, new launch site, new test stands, etc. For a rocket you will likely launch one every two years and which disentegrates into launch. Hugely expensive.
Quick and short answer, China study what others do and takes their idea if it fits China's need, China does NOT exactly copy them. China cares what they do, just do NOT care that much.
 

Quickie

Major
Chang'e 5 enters lunar orbit just 5 hours ago.

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China's Chang'e-5 probe enters lunar orbit
Source: Xinhua| 2020-11-28 22:49:31|Editor: huaxia

BEIJING, Nov. 28 (Xinhua) -- China's Chang'e-5 probe decelerated and entered the lunar orbit on Saturday, completing a vital step on its way to collect and return moon samples, the China National Space Administration (CNSA) announced.
After flying about 112 hours from Earth, an engine on the probe ignited when it was 400 km away from the surface of the moon at 8:58 p.m. and shut down after about 17 minutes, the CNSA said.
The probe performed the braking without incident and entered the lunar orbit successfully, according to the real-time monitoring data.
Chang'e-5, comprising an orbiter, a lander, an ascender, and a returner, has carried out two orbital corrections during the Earth-Moon transfer, achieving its expected goals.
Afterward, it will adjust the altitude and inclination of its orbit around the moon. When the time is appropriate, the lander-ascender combination will separate from the orbiter-returner combination, implement a soft landing on the near side of the moon, and carry out automatic sampling as planned. Enditem
 

gelgoog

Senior Member
Registered Member
I didn't say it was a straight copy. Besides there is nothing wrong with following the path already trailed by someone else.
 

siegecrossbow

Brigadier
Staff member
Super Moderator
Chang'e 5 enters lunar orbit just 5 hours ago.

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China's Chang'e-5 probe enters lunar orbit
Source: Xinhua| 2020-11-28 22:49:31|Editor: huaxia

BEIJING, Nov. 28 (Xinhua) -- China's Chang'e-5 probe decelerated and entered the lunar orbit on Saturday, completing a vital step on its way to collect and return moon samples, the China National Space Administration (CNSA) announced.
After flying about 112 hours from Earth, an engine on the probe ignited when it was 400 km away from the surface of the moon at 8:58 p.m. and shut down after about 17 minutes, the CNSA said.
The probe performed the braking without incident and entered the lunar orbit successfully, according to the real-time monitoring data.
Chang'e-5, comprising an orbiter, a lander, an ascender, and a returner, has carried out two orbital corrections during the Earth-Moon transfer, achieving its expected goals.
Afterward, it will adjust the altitude and inclination of its orbit around the moon. When the time is appropriate, the lander-ascender combination will separate from the orbiter-returner combination, implement a soft landing on the near side of the moon, and carry out automatic sampling as planned. Enditem

When will it land?
 

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