Chinese reusable technology – next dimension of competition with USA

China seems to spot how important is adding reusable technology to launch vehicles and started to improve pace of development of own technology, which could help in reducing prices of delivering payload to orbit.

Once in 2016 Chinese news agency Xinhua informed about progress in development of reusable rockets program in China. News from April 2016 was unfortunately not detailed enough to evaluate how advanced is reusable rocket program. It was only described, that unspecified Long March rocket was used to conduct test of "parachute system" for recovering first stage of the rocket. This technology seemed little outdated - boosters used for Space Shuttle years ago were also falling on parachutes, but it was not possible to use them as fast and easy as first stage of SpaceX Falcon-9, not to mention about New Shepard designed by Blue Origin. Now we know, that China Association for Science and Technology and China Academy of Launch Vehicle Technology are in fact working on various systems of reusable technology simultaneously. More surprising is fact that both organizations are working on completely new rockets, not on technology which could be easily adapted to present launch vehicles.

These new launch vehicles are both designed to use reusable first stages. First rocket was designed as smaller, with special parachute system for recovering its first stage. Rocket will be long for 29 m with diameter of the first stage at 3.35 m and mass under 100 t. It will be able to lift up to 650 kg of payload to SSO orbit with altitude of 700 km. First stage will be powered by engines fueled with LOX and Methane, what will make rocket more environment friendly and also give result in lower launch price. Two engines of the first stage will provide at least 600 kN of thrust each at sea level, with second stage, with diameter at 3 m, will be equipped with engines fueled with LOX/methane providing thrust in vacuum at 80 kN. Payload fairing will be 3 m in diameter. Recovery system will be based on parachutes: two pilot for deploying two drag parachutes for reducing speed. Three main parachutes will serve for final speed reduction and soft landing. It was not unveiled where CNSA is planning to place landing zones - if first stage will land only using parachutes, without any retro thruster system, landing on present landing zones placed in Inner Mongolia will be hard without damaging booster. CAST and CALT are planning to use special system of airbags for shock protection, but considering dimensions of stage and speed of landing, airbag system could not be sufficient for safe landing.

Another project assumes using propulsion for landing instead system of parachutes. It is larger rocket with length of 37.5 m, weight of 184 t and payload capacity for LEO of 1500 kg and for SSO orbit - 800 kg. Again diameter of the first stage is 3.35 m and 3 m for second stage. Propulsion is based on LOX/Methane engines, but in this project first stage will be equipped in three engines with sum thrust of 1800 kN. Due the exact same thrust of engines which are planned to be used, we can assume that engines will be identical as engines used in the first project. Second stage will be also based on LOX/methane engines with thrust at 80 kN and it will be probably equipped with identical model of engines like in the first project. IN case of this rocket reusable technology is more advanced. First stage is designed to land using main propulsion and utilizing fuel from main tanks. It will perform descent on launch trajectory to reach launch pad and land using (probably) deployable fins. Unfortunately no details on steering system, attitude control system or avionics were unveiled. Since now CALT and CAST have finished only tests of parachute systems for first project, which seems easier; nothing is known on second project, which definitely will push Chinese space industry upwards in rank of most innovative space industries in the world.

China seems to have plans to create launch vehicle with comparable possibilities in reusable technology as Falcon-9 rocket by American SpaceX. Chinese project seems to be interesting especially in second version, but it is worth to remind that Falcon-9 is able to deliver to LEO 10 t of payload using conventional LOX/RP-1 propulsion. Chinese rockets are small launch vehicles and reusable technology will probably change price per kilogram of payload extensively and will help China to dominate market of small launch vehicles. If heavy rockets are concerned, China probably will still rely on conventional rockets, which still are less expensive for customers than comparable American launch vehicles.

Sources:
http://www.chinaspaceflight.com/rocket/Reusable-Launch-System.html

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