China's Space Program News Thread

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The engine which propels China's Long March-7 carrier rocket for its successful maiden flight into space on Saturday is not only the pride of researchers and designers in Xi'an but is the hope and guarantee for the country's space cargo shuttling project as well.

Thanks to this engine, the Long March-7 has boasted a thrust which is 60 percent more powerful than its predecessors. Designed by China's Academy of Aerospace Liquid Propulsion Technology, the Long March-7 engine has got an improved specific impulse by 15 percent because of its innovative circulation mechanism and completely new structure.

"This engine enjoys completely independent intellectual property rights and all its raw materials, components, procedures and diagnosis are made and formulated here in China," says Liu Zhanguo, deputy chief designer of the Long March-7 carrier rocket.

The engine is up to par with internationally advanced levels and some of its capabilities have even surpassed the current international norms. This engine is the genuine core and kernel of China.

 

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Yuanzheng-1A, will conduct several extended experiments after it deployed the last payload to the earth orbit Sunday afternoon.Yuanzheng-1A (Expedition-1A), the upper stage of Long March-7, has the capability to deploy several payloads to different destinations through multiple ignition missions.

"This time, we take the advantage of Yuanzheng-1A's powerful mobility to put every satellite on the different orbits. It is advanced internationally," said Wang Guohui, technical head of the Long March-7 load combination of China Academy of Launch Vehicle Technology.

Yuanzheng-1A will continue to be upgraded in the restart capability and overall orbital transferring ability to conduct more space missions in the future.

"We expect to develop this upper stage to be equipped with infinite restart capability. In addition, working period on orbit is expected to be longer. Besides satisfying the need of current missions, it will be employed in deep-space detection and on-orbit maintenance in the future," said Wang Guohui.

 

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A small spacecraft sent into orbit by the Long March 7 rocket launched from Hainan in southern China on Saturday is tasked with cleaning up space junk, according to the government, but some analysts claim it may serve a military purpose.

The Aolong-1, or Roaming Dragon, is equipped with a robotic arm to remove large debris such as old satellites. Tang Yagang, a senior satellite scientist with the China Aerospace Science and Technology Corporation, said the Aolong-1 was the first in a series of craft that would be tasked with collecting man-made debris in space.

For instance, it could collect a defunct Chinese satellite and bring it back to earth, crashing it safely into the ocean, he said.

“China, as a responsible big country, has committed to the control and reduction of space debris. In order to fulfil the obligations and responsibilities, our country is [working endlessly towards] achieving a technological breakthrough in space debris removal technology,” Tang says on the website of the China National Space Administration.

But the question is: did China develop the cutting-edge technology only to clean up space junk? “It is unrealistic to remove all space debris with robots. There are hundreds of millions of pieces drifting out there,” said a researcher with the National Astronomical Observatories in Beijing.

To the military, the robot had potential as an anti-satellite weapon, the researcher said. The Roaming Dragon is small, weighing only a few hundred kilos, so the prototype could be produced and launched in large numbers.

During peacetime, the craft could patrol space and prevent defunct satellites from crashing into big cities such as Shanghai or New York. During wartime, they could be used as deterrents or directly against enemy assets in space, said the researcher.

It was also a “clean” anti-satellite weapon, the researcher said. In 2007, China conducted an anti-satellite test which blew up a dead weather probe with a missile. The test prompted an international outcry because the explosion generated such a large volume of debris. “This time no one will point a finger [at China],” the researcher said.

Another mainland space engineering scientist said the role of the craft to pick up space debris was a “bold experiment” with a high chance of failure. It looks simple, but some enormous challenges lie ahead, some that no other nation has solved,” said the expert. The development of the technology was mainly supported by the military, and kept confidential, he said.

The first challenge in such missions was to get close to a “non-cooperative target”, the scientist said. But China had conducted numerous such rendezvous flights, he said. During the docking of the Shenzhou manned spacecraft to the Tiangong space laboratory, for instance, the two vehicles constantly exchanged information.

The Aolong-1, by contrast, would be trying to rendezvous with a piece of cold, unresponsive debris. It would need to search for and identify the target, then plan and adjust its own course of approach. Another challenge involves reaching out to any debris with Aolong’s robotic arm.

To get a firm grip, the arm must aim for a specific target area – something that in space is likely to be constantly changing. Sensors and computers on Aolong will have to analyse the fast, irregular patterns of the tumbling target to guide its arm. Such challenges would test China’s technology to the limit, said the expert.

China is not the only country developing the technology. The European Space Agency is expected to approve a similar project called e.deorbit later this year.

The ESA was considering two different ways to capture the debris: one using a net and the other a robot arm. With a projected launch in 2023, the e.deorbit robot would “target a European derelict satellite in low orbit, capture it, then safely burn it up in a controlled atmospheric reentry,” the ESA says on its website.

The ESA also claims the e.deorbit would be “the world’s first active debris removal mission”, though that is no longer true given the launch of Aolong-1.

The United States Defence Advanced Research Projects Agency (Darpa) plans to launch a larger, more sophisticated craft for the US Air Force in 2020. The Phoenix in-orbit servicing programme had been scheduled for launch last year, but was delayed by technical and cost concerns.

Unlike the Aolong and e.deorbit, the Phoenix would also be able to carry out jobs such as repairing, upgrading and refuelling ageing satellites. It would even be able to “turn foreign satellites into US spy satellites”, according to the US air force.

Chinese researchers with the 502 Institute at the China Aerospace Science and Technology Corporation said last year that China would launch a multi-tasking space robot similar to the Phoenix, also by about 2020.

 

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The satellite lifecycle would long be gone before you need to refuel an ion thruster.

In other words, you're still claiming it's as good as no propellant is required?

The thing is this: Although the amount of propellant required is smaller, maybe 10 times smaller, its weight and the weight of the additional equipment required to generate and store electricity for the ionization, still constitute a significant part of the weight of the satellite.

At the present stage of development, the technology is still being tested on experimental satellites and seem to be more suited for deep space probes than satellites possibly because of the limitation of the small thrust.

 

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This is old new since most of the next generation satellites will be powered by ion thrusters that doesn't need refueling.

Ion propulsion will be used on "some" GEO communication sats and deep space spacecraft. Chemical will still be the most used propellant .

 

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how much cheaper this new LM-7 compared to old LM-2 series ... i.e $/kg cargo.

Difficult to say, but we know those old launchers used hypergolic propellant mix that are more expensive than kerolox...

 

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Difficult to say, but we know those old launchers used hypergolic propellant mix that are more expensive than kerolox...

Yes, also with the new much improved engine YF-100 (payload to LEO 13.5 ton or SSO 5.5 ton) compared to LM-2F with 4 YF-20B (payload to LEO 8.4 ton) ... roughly 61% improvement. I'd expect the cost would be significanyly lower ... perhaps 40%-50% cheaper ... if this is the case, it will be extremely competitive as the LM-2F is already very competitive

 

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The satellite refueling device is interesting. I remember someone here talked about it or maybe somewhere else. But anyways, it is an interesting idea. That will be very economical for operating satellites.

It is not obvious that in-orbit refueling system will be economical at all. This device will likely be expensive; It will be like buying a new pricey battery for a old laptop...

 

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Wenchang Satellite Launch Center...

 

[SamuraiBlue]

Ion propulsion will be used on "some" GEO communication sats and deep space spacecraft. Chemical will still be the most used propellant .

What other sats beside HO satellites do you think is requires to periodically use thrusters to regain altittude?
LO satellites are usually spy satellites but those use chemical propellants because they need to change orbit quickly not because ion thrusters are not available.

As for automated refueling they are already in use in a sense since the Japanese H-II, Russian Progress, European ATV, commercial Dragon, and commercial Cygnus Transfer Vehicle that sends supplies to the ISS are all automated resupply space vehicles.