China Aerospace Science and Industry Corp. [CASIC] intends to offer solid-propellant rockets as alternate launch vehicles for heavyweight spacecraft. All of China's heavyweight spacecraft, including large satellites and manned spaceships, use liquid-fuel rockets as launch vehicles because their lift capacity is greater than existing solid-fuel models. But solid-propellant engines have advantages-they are less complicated, need less time for prelaunch preparations, place fewer demands on launch facilities and are more mobile.
CASIC began to develop Kuaizhou, which means speedy boat in English, series solid-fuel rockets in 2009 as a low cost, quick-response rocket family for the commercial launch market. It has launched three of the rockets-two Kuaizhou 1s and one Kuaizhou 1A. The Kuaizhou 16, a small model, has a diameter of 3.5 meters and can place large satellites-those weighing up to 5 tons-into a low-Earth orbit. Rockets in this category are the most used on the launch market so the Kuaizhou 16 should have bright prospects.
The rocket launch project called Kuaizhou 11, a solid-fuel carrier rocket, will mainly be responsible for sending mini satellites and sun-synchronous orbit small satellites. According to China Central Television, the Kuaizhou 11 will have its maiden launch carrying six satellites in early 2018.
By December 2017 design work had begun on two new-generation solid-fuel carrier rockets at CASIC. The Kuaizhou 21 will mainly be tasked with serving State space programs, such as the space station, while Kuaizhou 16 is targeted at commercial satellite makers. With a diameter of 4.5 meters, Kuaizhou 21 will be the largest and tallest in the Kuaizhou rocket family. The rocket's launching capacity is similar to that of the United States' Falcon 9 Full Thrust, and it will be capable of sending a 20-metric-ton spacecraft to a low-Earth orbit. It also will be powerful enough to transport supplies to the country's future space station or to ferry robotic probes to planets far from Earth.
The key to a solid-propellant, heavy-lift rocket is a powerful, reliable engine, which is under development at the CASIC Fourth Academy. The engine will have a diameter of more than 4 meters and a liftoff thrust of more than 1,000 metric tons. Engineers have had to overcome a host of technical obstacles because China had never developed such a large and sophisticated solid-propellant engine. That meant there were some gaps in their knowledge of structure, materials and mechanics. The bigger a rocket engine is, the harder the research and development are. It will weigh hundreds of tons. Its ultralarge size will generate a number of technical or manufacturing problems for engineers and workers.
As of the end of 2017, the ignition of China's ultra-large diameter solid rocket motor to test key technologies was planned for February 2018, more exactly, during the Spring Festival holiday, but as of 01 May 2018 there was no news of this test. A full-scale verification test was held in the second quarter of 2018. This solid rocket motor, developed by the No.4 Research Institute of China Aerospace Science & Industry Corp, has a diameter exceeding four meters [156 inches]. Chinese reporting claims this created a new world record by a large margin. The previous record, held by America, was 3.7 meters [144 inches] on the Space Shuttle [although the US conducted ground tests of motors with nearly twice this diameter in the 1960s].
Liang Jiqiu, chief designer of the rocket named Kuaizhou said in an interview that the solid rocket motor will be used in China's Kuaizhou-21 and Kuaizhou-31 large-thrust solid-propellant carrier rockets. The Kuaizhou-21 has a maximal near-earth orbit carrying capacity of 20 tons , while the Kuaizhou-31 has a maximal carrying capacity of 70 tons in the near-earth orbit. Kuaizhou 31 would be almost three times more powerful than the Long March 5, long the country's biggest and mightiest rocket.
Specifications for the larger rockets are sparse. One published artwork suggests an overall length of about 25 meters for the KZ-21, only slightly less than the 19.5 meter KZ-1. This is clearly too small for the claimed payload. Another artist's concept suggests an an overall length of about 45 meters for the KZ-21, which is probably closer to the mark. With a diameter of 4 meters, the KZ-21 would have a cross section of 12.5 square meters, in contrast to the 1.5 square meter cross section of the 1.4 meter diameter KZ-1, or the the 3.8 square meter cross section of the 2.2 meter diameter KZ-11. With a 2.2 meter diameter, the KZ-11 appears to be about 22.5 meters long, for a total volume of roughly 85 cubic meters. With a LEO payload of 30,000 kg, the KZ-21 has roughly 20 times the payload of the 1,500 kg KZ-11. In very round numbers, this would imply a total volume of 1,700 cubic meters for the KZ-21, which with a diameter of 4 meters [and a cross section of 12.5 square meters] would imply a length in excess of 125 meters, an implausibly large number.
One published artist's concept depicts KZ-11A and KZ-21A configurations using strap-on boosters smaller than the core vehicle [presumably the KZ-11A uses KZ-1 motors as strapons, and the KZ-21A uses the KZ-11 as strapons. The claimed KZ-21 payload might be achieved by a pair of 4 meter strap-on motors [to achieve an effective aggregate motor length of 125 meters, while the claimed KZ-31 performace might be achieved with a cluster of four or six 4 meter strapons. These are extremely rough order of magnitude calculations, but they clearly demonstrate a mismatch between claimed performance and depicted configurations.
The early Kuaizhou series rockets are launched into space by the truck-mounted mobile launcher. In the first half of 2018, the Kuaizhou-11 solid-propellant carrier rocket will have its maiden flight, carrying six satellites. With a takeoff weight of 78 tons and a near-earth orbit maximal carrying capacity of 1,500 kg and a sun-synchronous orbit carrying capacity of 1,000kg/700 km, the Kuaizhou-11 will mainly send single or multiple small satellites and microsatellites into the near-earth and sun-synchronous orbits ranging from 400 km to 1,500 km.
With the ultra-large diameter solid rocket motor with a large-thrust, the carrying capacity of Kuaizhou series will be increased from 1 ton to 20 tons and the cost for launching a rocket will be further lowered to $5,000 per kilogram, highly competitive compared with the ruling price range of $20,000-30,000 per kg in the present world market. The coming out of the ultra-large diameter solid rocket motor is a significant milestone in China's commercial space flight development.
The KZ-1A rocket corresponds to the DF-21 medium range missile, and the KZ-11 rocket is not much smaller than the DF-41 heavy duety solid rocket ICBM. According to Chinese media, by 2020 the production capacity of the Aerospace Science and Industry Rocket company will be equivalent of 20 DF-21 missiles and 30 DF-41 ICBMs. Chinese media claims that this capacity would exceed that of the peak of the Soviet Union for such missiles.
|Rocket||ILC||PL to LEO||PL to SSO||GLOW||diameter||length||PL fairing|
|kg||430 kg||30 tonnes||1.4 meters|
|300 kg||250 kg||30 tonnes||1.4 meters|
|19.4 m||1.4 m|
|1,500 kg||1,000 kg||78 tonnes||2.2 meters|
|22.5 m||2.6 m|
|kg||kg||tonnes||2.2 meters +|
|5,000 kg||kg||tonnes||3.5 meters|
|30,000 kg||kg||1,500? tonnes||4.0 meters|
|kg||kg||tonnes||4.0 meters +|
|70,000 kg||kg||3,500? tonnes||4.0 meters+|
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