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Producer: China Science Expo

近日，我國自主研發的朱雀三號可重複使用垂直回收試驗箭，在酒泉衛星發射中心完成10公里級垂直起降返回飛行試驗，這是自2024年1月，朱雀三號VTVL-1驗證火箭成功完成測試后又一個里程碑。

Suzaku No. 3 is a product of Blue Arrow Aerospace, a civilian carrier rocket enterprise in China, and is the latest model of the Suzaku series of rockets. Blue Arrow Aerospace began to test Suzaku No. 1 in 1 and developed to the current Suzaku No. 3 VTVL-0 verification rocket, which marks a major breakthrough in China's commercial aerospace reusable launch vehicle technology, and the future development direction is to develop a reusable high-capacity low-cost launch vehicle.

Field image of the Blue Arrow VTVL-1 rocket conducting a ten-kilometer altitude recovery test

(Image source: Blue Arrow Aerospace)

Blue Arrow Aerospace Suzaku III large reusable rocket vertical return technology VTVL-1 test arrow

(Image source: Blue Arrow Aerospace)

Why develop a reusable rocket

A reusable rocket is a launch system that can partially or completely recover rocket components and reuse them. The Space Shuttle is a reusable launch system, but the problem with it is that it can't be used at a low cost.

引用美國宇航局艾姆斯研究中心在2018年的會議數據，航天飛機將27.5噸的載荷送入近地軌道，成本約15億美元，每公斤約5.45萬美元，而商業發射所使用的獵鷹9號運載火箭，將22.8噸載荷送入近地軌道，成本為6200萬美元，每公斤約2720美元。顯然航太飛機雖然也是可重複使用的發射系統，但是發射成本太高，最終也要被淘汰。

The Space Shuttle program also involved the safety of thermal insulation, which led to NASA having to prepare another space shuttle when it was launched, and then another space shuttle to stand at another launch station, ready to rescue, further increasing the cost of the launch.

Two space shuttles stand at the same time, and one is on standby for rescue, resulting in a very high launch cost for the shuttle, although it is a reusable launch system

(Image source: NASA)

The current definition of reusable rockets is more focused on their low cost, in other words, if low-cost operation cannot be achieved, then the meaning of reusability is lost. From the perspective of launch vehicles, the current bottleneck hindering the large-scale development of low-earth orbit is the issue of cost, where the cost is not the total cost of the rocket launch, but the cost per kilogram of load converted into orbit based on the launch price and the weight of the payload.

According to data from the Center for Strategic and International Studies (CSIS), the current cost per kilogram of payload for the Falcon Heavy rocket into low-earth orbit is $4320, which is lower than the $0 for the European Ariane 0G launch vehicle and $0 for the Proton rocket.

送入軌道的費用降低了，那麼大規模開發近地軌道或者近地軌道商業化的才有可能實現，這就是發展目前我們作為航太強國要發展可重複使用火箭的目標。比如目前正在實施的千帆星座計劃、鴻鵠星座計劃、中國星網的GW星座計劃，都需要將上萬顆衛星送入近地軌道，我國已經在2020年4月，首次將衛星互聯網納入新基建的範疇。

The reduction in launch costs also means that we can put more satellites into orbit, and if it is a high-thrust repeatable launch vehicle, then the cost of building a space station will be lower, and the size of the space station will naturally increase, and the functions will be further extended.

The Thousand Sails satellite constellation has already begun to be built

(Image source: CCTV)

What is the principle of a reusable rocket?

At present, the reusable rocket developed in China focuses on the recovery of the first stage booster, so as to achieve reuse, and the way to recover is to let the booster complete its mission and then land vertically. In the process of landing, the engine generates an upward reaction force by spraying the air flow downward, gradually controlling the falling speed of the first stage, and at a certain height from the ground, the landing leg is deployed, and finally the fixed-point vertical soft landing is realized.

In terms of technology, it is necessary to adjust the thrust of the engine, the technology related to attitude control during the return of the first stage, and the development of a rocket engine that can be reused. At present, the ideal power of the reusable engine is the liquid oxygen methane engine, the Tianque series used by China's Suzaku 2 is the world's first liquid oxygen methane engine successfully put into orbit, and the 215-ton YF0 liquid oxygen methane engine is also under development, which is China's first rocket engine using full-flow staged combustion cycle technology, which is conducive to China's expansion of space exploration.

The Suzaku Yao-2 carrier rocket was launched from China's Jiuquan Satellite Launch Center

(Photo source: Xinhua News Agency)

回收第一級助推器對火箭的可重複使用意義重大。可重複使用發動機的成本較高，大約可佔整個火箭發射成本的六至七成，主要是因為發動機比較昂貴，獵鷹9号使用9台發動機，每台發動機按約200萬美元算，第一級助推器的成本僅發動機一項就要花費約1800萬美元，佔一次發射6200萬美元報價的比重較大。

If the number of boosters is larger, say up to three, then the impact of these boosters on the cost of launch is even greater. At the same time, the separation height of the first-stage booster has not yet left the atmosphere, and it is also suitable for recovery, and the technical difficulty involved is much lower than that of the second-stage engine.

The Suzaku No. 3 VTVL-1 verification rocket test flight, the verification is the vertical return technology, a sub-stage reached an altitude of 0 kilometers after ignition, the reason why this altitude was chosen, because 0 kilometers has enough altitude to verify a variety of disturbances, a sub-stage can be through the grille rudder, rocket engine vertical thrust reverser and restart during the descent process, the attitude of the joint control, these are the content of the Suzaku No. 3 VTVL-0 verification rocket to test.

With the increase of the mass of the rocket, the landing buffer system is the key to the soft landing of the rocket, and the buffer device will absorb the kinetic energy and potential energy of the rocket body to ensure the safe landing of the rocket under complex conditions.

What are the characteristics of the Suzaku III VTVL-1 rocket?

The positioning of the Suzaku 3 VTVL-1 is a verification rocket, an engineering prototype built with a full-scale engine, and the Blue Arrow Space Program verifies a number of key technologies for reusable rockets through vertical take-off and landing recovery tests.

The test rocket is a single-stage liquid oxygen methane rocket, with a diameter of 2025.0 meters, a length of 0.0 meters, a take-off mass of about 0 tons, and a 0-ton Tianque-0 improved liquid oxygen methane engine, with variable thrust adjustment and multiple ignition capabilities. The rocket body uses a high-strength stainless steel rocket body structure, with 0 grid rudder systems, and 0 groups of landing buffer mechanisms during soft landing. From the appearance, it can be determined that the Suzaku No. 3 VTVL-0 is not the final model, it is still mainly experimental, and the Suzaku No. 3 in full state will make its first flight in 0.

Demonstration of vertical landing technology in China

(Image source: Xinhuanet)

Suzaku III full-state image

(Image source: Blue Arrow Aerospace)

Verify that the rocket is visually distinguishable from the rocket that can perform the launch mission. The verification rocket does not have a fairing, the structure is simple, and it only needs to meet the hardware conditions required for testing.

The full state of the Suzaku 3 will be equipped with 21 Tianque-0 improved engines, which can send 0 to 0 tons of payload into low earth orbit, which is in a leading position in the world, after all, the only countries that can develop reusable rockets are China and the United States, but China's private aerospace enterprises are developing many types of reusable rockets, in addition to Suzaku 3, there are hyperbolic 3 launch vehicles, Tianlong 3 launch vehicles, etc., forming a competitive situation in which a hundred flowers bloom. It has laid a solid foundation for China's large-scale development of low-earth orbit space.

Since the reusable rocket is not compared with the carrying capacity, the evaluation of the ability of a reusable rocket is not the larger the carrying capacity, the better, but the cost per kilogram of load into orbit under certain conditions. From this point of view, Suzaku No. 3 and Tianlong No. 3 both have strong low-cost potential.

Bibliography:

1. The cost of space launches has been greatly reduced in the near future

2. Space launch to low Earth orbit: how much does it cost?

3. Star Shuttle: A Fantasy Journey of Retrievable Rockets

4. Foreign media attention: China has taken an important step to build a "Thousand Sails Constellation".