China's Space Program News Thread

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taxiya

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The first "full engine" test of the "Gimbal behind turbopump" LOX-Kerosene engine was successfully conducted recently.

An earlier partial test was conducted a year ago
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The engine is a modification of YF-100 (120 ton class) LOX-Kerosene engine used as LM5 booster, LM7 core and LM6 upper stage. The engine and its test is to serve the purpose of developing the main engine for super heavy lift rocket (CZ-9) at 500 ton class (480 ton maybe). The 500 ton engine has successfully tested its turbopump last year.

Note, China is the 2nd after Russia/USSR to master this technology.

Note to note, USA does not have such engine. I know some will argue for SSME. SSME has its low-pressure fuel pump mounted on the shuttle orbiter, its high-pressure turbo pump is fixed with the combustion chamber and gimbaled together. The pump in "gimbal behind turbopump" is the high pressure high temperature turbopump that burns fuel and the pipe has to withstand that pressure and heat.
 

jobjed

Captain
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The first "full engine" test of the "Gimbal behind turbopump" LOX-Kerosene engine was successfully conducted recently.

An earlier partial test was conducted a year ago
Please, Log in or Register to view URLs content!


The engine is a modification of YF-100 (120 ton class) LOX-Kerosene engine used as LM5 booster, LM7 core and LM6 upper stage. The engine and its test is to serve the purpose of developing the main engine for super heavy lift rocket (CZ-9) at 500 ton class (480 ton maybe). The 500 ton engine has successfully tested its turbopump last year.

Note, China is the 2nd after Russia/USSR to master this technology.

Note to note, USA does not have such engine. I know some will argue for SSME. SSME has its low-pressure fuel pump mounted on the shuttle orbiter, its high-pressure turbo pump is fixed with the combustion chamber and gimbaled together. The pump in "gimbal behind turbopump" is the high pressure high temperature turbopump that burns fuel and the pipe has to withstand that pressure and heat.

I believe they're doing this because the LM-9's engines will be too heavy to gimbal as a whole assembly. The more mass they can keep stationary the better.
 

taxiya

Brigadier
Registered Member
I believe they're doing this because the LM-9's engines will be too heavy to gimbal as a whole assembly. The more mass they can keep stationary the better.
Yes, that is the main purpose. It seems to me that US has chosen to rely on SRB for max liftoff thrust eliminating the need for F-1 class liquid engine which could benefit from "gimbal behind pump".
 

Hendrik_2000

Lieutenant General
the latest Chinese satellite has resolution of 15 cm
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GF-11: How do you say KENNEN in Chinese?
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On July 31st, China added a new member to its Gaofen Earth Observation constellation: Gaofen-11 (GF-11) was launched atop a CZ-4B rocket. While the early Gaofen satellites were
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by their designers, this one is a bit more obscure. It was not in the list of planned Gaofen satellites, and the launch caught observers by surprise, so most likely it is a military satellite operating under the guise of the Gaofen programme.

However, the Chinese always lift a bit of the veil of secrecy by releasing footage of the launch, with views of the rocket and of the control center, but also footage of satellite separation. Interestingly, 3D computer models are used in the control center to represent the rocket and its payload, and these models are not censored by the CCTV state television. They even showed those models with some of the military
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, probably as a form of strategic signaling towards their competitors. That way they can show the United States for instance that they mean business when it comes to strengthening their intelligence capabilities. Here is the footage for GF-11:


The most interesting part is this image of the satellite still attached to the third stage of the Long March rocket.

gf11.jpg


Knowing the stage has a diameter of 2.9m, and is almost completely parallel to the virtual camera, the diameter of the satellite’s aperture can be estimated at 1.7m. That means it carries a big mirror: the largest mirror carried by a commercial Earth Observation satellite is Worldview 3 & 4 ‘s 1.1m mirror, manufactured in the USA by ITT Exelis. For non-commercial satellites, the French have published images of their Helios 2 spy satellites, suggesting they have a 1.4m mirror. GF-1 beats them all, and is in fact only outclassed in its category of an optical imaging satellite by two US products:

– the Hubble Space Telescope, which has a 2.4m mirror working at optical wavelengths

– the KENNEN optical spy satellites, generally known under the KH-11 designation, which are rumoured to have a similar mirror size to Hubble. This is supported by the fact that the National Reconnaissance Office gifted two 2.4m optical mirrors it no longer had use for to NASA, which plans to use it for its WFIRST observatory. Additionally, people who have seen high-resolution images of these satellites have described them as “
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“.

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Artist’s view of a KH-11 based on a modified Hubble image. Credit The Space Teview
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The Hubble Space Telescope
So China seems to have accomplished a great leap forward in space optics. As GF-11 is positioned on a 470km circular orbit, a 1.7m mirror would give it a ground resolution of 15 to 20cm, surpassing all commercial satellites and most reconnaissance satellites. This propels China into the select club of countries that can acquire
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satellite imagery, meaning the resolution is high enough to identify small hand-held weapons. Presumably the only members of this club are the US and now China, and that will continue to be the case in the foreseeable future, with maybe Russia joining them later if the
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program fulfills its promises.
 

Quickie

Colonel
The naming of the Rover is open to the world citizens.

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China unveils Chang'e-4 rover to explore Moon's far side


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Photo provided by State Administration of Science, Technology and Industry for National Defense shows the image of the rover for China's Chang'e-4 lunar probe. China's moon lander and rover for the Chang'e-4 lunar probe, which is expected to land on the far side of the moon this year, was unveiled Wednesday. The global public will have a chance to name the rover. (Xinhua)

BEIJING, Aug. 15 (Xinhua) -- China's moon lander and rover for the Chang'e-4 lunar probe, which is expected to land on the far side of the moon this year, was unveiled Wednesday.

Images displayed at Wednesday's press conference showed the rover was a rectangular box with two foldable solar panels and six wheels. It is 1.5 meters long, 1 meter wide and 1.1 meters high.

Wu Weiren, the chief designer of China's lunar probe program, said the Chang'e-4 rover largely kept the shape and conditions of its predecessor, Yutu (Jade Rabbit), China's first lunar rover for the Chang'e-3 lunar probe in 2013.

However, it also has adaptable parts and an adjustable payload configuration to deal with the complex terrain on the far side of the moon, the demand of relay communication, and the actual needs of the scientific objectives, according to space scientists.

Like Yutu, the rover will be equipped with four scientific payloads, including a panoramic camera, infrared imaging spectrometer and radar measurement devices, to obtain images of moon's surface and detect lunar soil and structure.

It will also endure vacuum, intense radiation and extremes of temperature. The moon has a large temperature difference between day and night, which can reach more than 300 degrees Celsius.

Both the lander and rover will carry international payloads for other countries.

The Chang'e-4 lunar probe will land on the Aitken Basin of the lunar south pole region on the far side of the moon, which is a hot spot for scientific and space exploration.

Direct communication with the far side of the moon, however, is not possible, which is one of the many challenges for the Chang'e-4 lunar probe mission.

China launched a relay satellite, named Queqiao, in May, to set up a communication link between the Earth and Chang'e-4 lunar probe.

The global public will have a chance to name the rover, according to State Administration of Science, Technology and Industry for National Defense.

Participants can submit their proposed names for the rover through the internet from Aug. 15 to Sept. 5, and the official name will be announced in October after several selection rounds.

Winners will be rewarded at most 3,000 yuan and invited to watch the lunar probe launch.

The name Yutu was chosen from 200,000 proposals submitted over two months worldwide.
 

weig2000

Captain
Two years ago, when China launched its civilian optical sensing satellite with an announced resolution of 0.5m. I was saying the military ones might have better resolution, probably at 0.25m. Admittedly, I thought it was a rather optimistic guesstimate. Well, now different western analysis have put the new GaoFen-11's resolution at 10-15cm.

It's a very impressive progress.

China closing the satellite imagery capability gap
Andrew Tate, London - IHS Jane's Defence Weekly
14 August 2018
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A Chinese Earth-observation satellite launched on 31 July from the Taiyuan Satellite Launch Centre may be capable of achieving ground-image resolution of 10 cm or less. If confirmed, this would give China a satellite-imaging capability second only to the United States and possibly comparable to the maximum resolution provided by US imaging satellites.

China’s state-owned Xinhua news agency reported that the Gaofen 11 satellite is an “optical remote-sensing satellite” that was carried aloft by a Long March 4B rocket “as part of the country’s high-resolution Earth observation project”. An article in the Science & Technology Daily , the news outlet of China’s Ministry of Science and Technology, noted that the satellite’s ground resolution was “at the sub-metre level”.

Previous Gaofen satellites are part of the civil China High-resolution Earth Observation System (CHEOS). However, Gaofen 11 was not included in previously released information related to the civil programme, so it is likely that this satellite will have a primarily military role.

A video of the launch was released by state-owned broadcaster China Central Television (CCTV), and computer-generated 3D images displayed in the satellite control centre were also shown. These included a representative image of the satellite while still attached to the rocket’s third stage but after the payload faring had been jettisoned.

Analysis of this image published on the website SatelliteObservation.net compared the size of the satellite body with the known diameter of the third-stage module and concluded that the mirror lens is around 1.7 m across.

The satellite has been placed in an elliptical near-polar orbit, which gives it an altitude of 693 km at its apogee and 247 km at its perigee, which occurs at 10:00 h local time at latitude 20° N -– such as when passing over the South China Sea, India, or Hawaii.
 
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