Lanceur Longue Marche

Le plus récent des lanceurs chinois "Chang Zheng-5" (Longue Marche-5), effectuera son premier vol en 2014, a rapporté vendredi l'agence Chine Nouvelle.

"Le lanceur se distingue par un haut niveau de fiabilité, de sécurité, de capacité d'adaptation et par un faible coût de production. Son développement accélérera sans aucun doute la domestication de l'espace et couvrira les besoins du marché chinois dans l'utilisation des ressources spatiales à des fins pacifiques au cours des 30 à 50 ans à venir", a affirmé l'agence.

Mesurant 60,5 mètres de long, le lanceur possèdera une masse au décollage de 67,5 tonnes et développera une poussée au lancement de 835 tonnes; son cône protecteur mesurera 5,2 mètres de diamètre, selon l'agence.

China Studies Moon Rocket

China is studying the design of a Moon rocket in the class of the Saturn V, as the Obama administration proposes canceling the U.S. successor to the Apollo launcher, Ares V.
The country also is developing another new rocket, the “medium thrust” Long March 7, the China Academy of Launch Vehicle Technology says. This new launcher joins the Long March 5 heavy rocket and the Long March 6, which was mentioned last year and is now defined as a “small-thrust” launcher. Long March 5, 6 and 7 will form a family of rockets, it says.
Chinese space officials have said that the Long March 6 was based on the side boosters of the Long March 5. Those side boosters come in two sizes, which could be arranged variously as first or second core stages or as boosters. Long March 7 is therefore likely to be a more powerful combination of the same collection of equipment.
China said last year that development of Long March 6 had begun and that it would appear in 2013, a year before Long March 5.
The Long March 5 has a core diameter of 5 meters (16 feet) with boosters of either 3.35 meters or 2.25 meters, officials say. The 3.35 meter diameter, the same as that of the original Long March series (Long March 1, 2, 3 and 4) was chosen as the largest that would fit within the loading gauge of the Chinese railways, one program executive told Aviation Week last year. Established tooling could also be used with the 3.35 diameter booster, even though the materials and structural design would be different, that executive said.
But the facilities of the space industry base under construction at Tianjin will be adaptable to handle rocket diameters of 8 or even 10 meters, an official there said last year, hinting that the plant was prepared to build an equivalent of the Saturn V, whose first-stage diameter was 10.1 meters.
Confirming that such a Chinese Moon rocket is at the study stage, the vice-president of the China Academy of Launch Vehicle Technology, Liang Xiaohong, says it will have a thrust at lift off of 3,000 tons. The Saturn V’s S-1C first stage generated 7,648,000 lb. (3,470 metric tons) of thrust at sea level.
Liang says the payload of the Moon rocket has not been defined, which seems to suggest that the achievable launcher technology will determine the scope of the mission, rather than the desired mission determining the performance of the rocket.
The Chinese government has not authorized a manned Moon mission, but it is clear the country’s space sector is at least being allowed to prepare for one.
The latest announcements have been reported by Xinhua news agency and the China Daily, an English-language newspaper whose content is intended for foreign consumption.
Liang says Long March 5 launchers will be used in the preparatory stage of a Moon landing.
Potentially, there will be a lot of them. The Tianjin base will be able to build two a year when its first stage is completed in 2011 but its capacity will eventually rise to one Long March 5 per month.
About 100,000 square meters of workshops have been completed so far at Tianjin, with an initial investment of 1.5 billion yuan ($220 million). The final investment will be 10 billion yuan.
“A moon landing program is very necessary, because it could drive the country’s scientific and technological development,” the China Daily quotes Bao Weimin of the Chinese Academy of Sciences as saying.
The Long March 5 will be needed for China’s plans for a full space station due to follow an unknown number of Tiangong laboratories before 2020. The station’s core module will have a mass of 20 tons. But Qi Faren, who designed the Shenzhou manned spacecraft, says the Long March 5 will first be used to launch the 8-9 ton Fengyun weather satellite to geostationary orbit. The current Long March series could not perform that mission.
Long March 5 will serve for 30 to 50 years, Liang says.
A modified Long March 2F will launch Tiangong 1 next year. Liang says that rocket has needed 170 modifications, including 38 major changes, to launch Tiangong 1, which will be initially unmanned but eventually able to accommodate astronauts performing experiments

Beijing

[Vous devez être inscrit et connecté pour voir cette image][Vous devez être inscrit et connecté pour voir ce lien] alt="" />The Chinese space industry is studying a Moon rocket in the class of the Saturn V while separately moving ahead with a medium-heavy launcher that will complete a modern, modular family of launch vehicles. Chinese space engineers appear to be planning to assemble manned lunar spacecraft in orbit with two or more launches per mission. The medium-heavy launch vehicle, previously foreshadowed as a relative of the new Long March 5 heavy launcher, is being developed under the name Long March 7. Long March 5 and 7 and the lighter Long March 6 will form a family of rockets, says the China Academy of Launch Vehicle Technology. Chinese industry will maximize economies of scale in production by building the three basic vehicles for a wide range of payloads while, in almost all applications, using only three basic stage modules and, apparently, two engine types. The launcher for manned lunar missions, several times larger than even the Long March 5, would have a thrust at lift off of 3,000 tons, says the vice president of the academy, Liang Xiaohong, adding that the payload has not been defined. By comparison, the S-1C first stage of the Apollo program’s Saturn V generated 3,470 metric tons at sea level. The news of Chinese studies into such a mighty launcher comes as the Obama administration seeks to cancel the U.S. equivalent, the Ares V of the Constellation program, whose six main engines and two solid-fuel boosters would put out about 4,300 tons of thrust. Since the lift-off thrust of the launcher will be lower than that of the Saturn V, it will be unable to deliver as great a mass to lunar orbit—probably about 35 tons, compared with the U.S. launcher’s 45 tons, estimates one U.S. rocket engineer. But NASA needed that 45 tons for missions that were close to the minimum conceivable—brief stays on the Moon by two astronauts. Moreover, the Apollo equipment was built so lightly that even now the Chinese would probably struggle to do that minimum mission with much less mass. So the thrust of the proposed Moon rocket strongly suggests that Chinese engineers plan to launch their lunar craft in at least two parts and assemble it in low Earth orbit, as NASA planned in the Constellation Program by launching the crew capsule separately. In proposing a Moon launch vehicle, the Chinese engineers are avoiding the risky alternative of a longer succession of Long March 5 launches. Getting 3,000 tons of thrust under a single rocket presents a formidable technological challenge for China, whose largest engine so far, the YF-100, generates thrust of just 120 tons. The Soviet Union’s disastrous experience with the 30-engine first stage of its N-1 lunar launcher argues against attempting such an arrangement with the YF-100. China could alternatively develop or buy larger powerplants. The five F-1 engines of the Saturn V each generated 694 tons of thrust. The Russian RD-171, used on the Zenit launcher, puts out 770 tons from four thrust chambers. Four RD-171s would deliver 3,080 tons, and they would probably fit into a rocket airframe with a diameter of 8-10 meters (26-33 ft.), says the U.S. engineer.

An official from the Chinese space industry base under construction at Tianjin said last year that the plant could be adapted to handle rocket diameters of 8-10 meters. The Saturn V’s first-stage diameter was 10.1 meters.
The YF-100 seems to have been developed with Russian technology and is a key element in the family of smaller launchers that China already has in development. While there are few new details from Chinese industry, synthesizing them with earlier information suggests that two YF-100s will act as the first-stage engines for the Long March 7.
China is developing three basic rocket modules, with diameters of 2.25 meters, 3.35 meters and 5 meters and lengths that vary with their roles as first or second stages or side-mounted boosters. Matched with those modules are two new engines, the kerosene-fueled YF-100 in the two narrower bodies (hence module names, K2 and K3) and the liquid-hydrogen fueled, 50-ton-thrust YF-77 in the wider module (called H5). If the Chinese are following plans revealed a few years ago, then two stacked K2 modules form the Long March 6 while two stacked K3s make up the core of the Long March 7, with K2s as boosters.
The Long March 5 core will be built up from one or two H5 modules, with various combinations of K3 and K2 boosters. The largest version, Long March 5E, is intended to deliver 14 tons to geostationary orbit, its low-orbit payload unstated.
The description of Long March 7 corresponds with the mid-sized launcher that the academy detailed in 2007. The configuration displayed then had the two K3 core modules, four K2 boosters and a special 3-meter-dia. module, H3, that would presumably be an optional third stage for missions beyond low Earth orbit. But the range of payloads quoted for Long March 7, 10-20 tons, shows that it would be built with a variety of booster combinations. A single YF-100 would presumably provide second-stage propulsion.
The payload of the Long March 6 is unknown. China said last year that development of that launch vehicle had begun and that it would appear in 2013, a year before Long March 5. It is now described as a low-thrust launcher. The engine of the K2-2 second stage has not been stated, but the designation shows that it is fueled by kerosene, implying that it, too, is a YF-100. It would be unusual for a second stage to have the same engine as the first, since that would result in poor throw weight for the size of the rocket, though it would simplify production.
China’s strict approach to modularity has been made possible by the shortcomings of its current technology, based on hydrazine-fueled engines in the earlier Long March launchers. Hydrazine is stored and ignited easily and thereby eases rocket design, but it is costly and toxic, and has much less energy for its weight than kerosene. In planning a future rocket family, China could therefore afford to begin with a clean sheet of paper.
The old hydrazine Long Marches may be needed after the new family goes into service, depending on the size of the gap between Long March 6 and 7.
Some established technology is being brought forward for Long March 7. Chinese media say the Long March 7 will be developed from the technology base of the Long March 2F, China’s human-rated launcher. However, the new rocket’s stated payload, far above the 8.4 tons of the Long March 2F, makes clear that the Chinese have introduced the YF-100.
Kerosene propulsion implies a complete redesign of the launcher body, since it demands liquid oxygen that needs cryogenic storage. Unless Long March 7 retains the hydrazine-engine core of older Long Marches, using YF-100s only in its boosters, it should be a fundamentally new launch vehicle.

The original core diameter of the old Long Marches has been kept in the K3 modules. Another non-Chinese rocket engineer suggests that, since Chinese industry has upgraded the equipment in its launchers over the past few years—renewing such systems as guidance and diagnostics, and installing new technology such as a health management system—it probably plans to move those items across to the Long March 7.
A Chinese industry executive confirms to Aviation Week that the K3 module has a new structure with new materials. The diameter has been kept for two reasons, he says, one being the original reason for its choice four decades ago: 3.35 meters is the most that will fit within the loading gauge of the Chinese railways. The second reason is that keeping the old diameter meant that costly tooling could also be retained.
The executive says one of the biggest challenges in the Long March 5 program has been building tools that can work on the greater diameter with adequate precision. That challenge would be even bigger with an 8-10-meter diameter.
The latest announcements have been reported by Beijing’s Jinghua Times, Xinhua news agency and the English-language China Daily, whose content is intended for foreign consumption. The news coincides with the annual meeting of the National People’s Congress, which is often an occasion for stirring patriotic announcements.
Confusingly, the Jinghua Times says the Long March 7 is needed because there is no other Chinese launcher with a capacity of 10-20 tons. But the two smallest versions of the Long March 5 could carry 10- and 18-ton payloads to low Earth orbit.
The Long March 5 program is at the engineering-model stage. Liang says the first full-diameter part, the bottom of a tank, has been welded together.
Long March 5 launchers will be used in the preparatory stage of a Moon landing, he says, implying that final execution of the manned landings will rely on the proposed Moon rocket.
Potentially, there will be a lot of Long March 5s. The Tianjin base will be able to build two a year when its first stage is completed in 2011 but capacity will rise to one a month. About 100,000 sq. meters of workspace is ready, with an initial investment of 1.5 billion yuan ($220 million). The final investment will be 10 billion yuan. “The launch base on Hainan [island] for big rockets is basically complete,” adds Liang.
The Long March 5 will be needed to put a space station into orbit after an unknown number of Tiangong laboratories before 2020. The station’s core module will have a mass of 20 tons. Qi Faren, who designed the Shenzhou manned spacecraft, says the Long March 5 will first be used to launch an 8-9-ton Fengyun weather satellite to geostationary orbit.
Next year a modified Long March 2F will launch Tiangong 1, which will be unmanned as a docking target before accommodating astronauts doing experiments. Beginning with that launch, greater reliability and accuracy will be needed from China’s rockets, says the Jinghua Times. “Before Shenzhou 7, a launch failure meant only the failure of one mission,” Liang tells the paper. “But from Tiangong 1 until Shenzhou 8, 9 and 10, one launch failure will imply the failure of the whole project.”
That clearly excludes the use of new launch vehicles in the upcoming stages of the manned space program, but Xinhua says Long March 7 might be used in the Chang’e program of unmanned lunar probes.