Without too much fanfare, China is continuing its programs of reusable rockets, including the future Long March 8, which should fly in 2021. The main stage will return back to earth on the vertical position, like that of SpaceX’s Falcon 9. But the technological choices look different.
Like SpaceX and Blue Origin in the United States, the Chinese government and some private companies are trying hard to would develop a partially reusable launcher. This was hinted by Long Lehao of the Chinese Academy of Launching Technology (CALT). This specialist unveiled the plans for this future rocket, called Long March 8 (CZ-8) on April 24 at a space industry conference in Harbin. A first launch is planned in 2021.
This two-stage launcher and booster would have a reusable main stage that would land back on Earth vertically near its launch site. Depending on the number of boosters used, from two to four depending on the performance requirements of the launcher, CZ-8 will be capable of launching up to 4.5 tonnes in a sun-synchronous low orbit (approximately 700 km) and 2.5 tonnes in geostationary transfer orbit .
This launcher will be marketed to satellite operators and offered in international markets for the launch of satellites open to competition. With one condition however: that the satellites to launch are “ITAR free”, that is to say built without components made in the United States.
To reduce development costs and risks, the CZ-8 will use elements from other launchers already in service. Thus, the main stage, with two YF-100 engines, will be derived from that of the Long March 7. This engine is derived from the Russian RD-120 kerosene and liquid engine used by the Zenith launcher.
Bao Weimin, director of the Science and Technology Commission of China Aerospace Science and Technology Corporation, said China has opted for a different method than the one chosen by SpaceX for its Falcon 9 launcher. To recover the main stage, SpaceX uses the so-called Toss-Back maneuver, which consists of turning the engine around, reversing and re-lighting. In this configuration, the stage uses rocket propulsion to provide the pulses for ground return, atmospheric phase braking and vertical landing.
Originally, the Russian RD-120 engine is not designed to be recovered and reused. Due to a lack of detailed information on Chinese technology choices, one can only assume the method of recovery. What is known from other programs suggests that China will use parafoils or balloons to brake and ensure the return of the main floor and boosters CZ-8. Some time ago, a recovery test was performed on a booster braked by a balloon.
For China, the reuse of launchers is also a public safety issue. Unlike the United States, whose launch sites are close to the coast, Chinese launchers fly over inhabited areas before returning to space. At each launch, the authorities are forced to evacuate the areas above which the separation and falling of stages and boosters take place. Added to this risk is the crash of a launcher in case of failure, with all the consequences that this may have for people and infrastructure on the ground.
In the longer term, by 2035, China is aiming for a fleet of fully reusable launchers. It is also working on a reusable spacecraft by 2025 and a fully reusable two-stage launcher by 2030.