Super cool! 10 km vertical take-off and landing return flight, my country's reusable rocket has made a new breakthrough!

At noon on September 11, China's independently developed Zhuque-3 VTVL-1 reusable vertical take-off and landing recovery test rocket completed a 10-kilometer-level vertical take-off and landing return flight test at the Jiuquan Satellite Launch Center, marking a breakthrough in China's commercial aerospace technology in reusable launch vehicle technology and a key step towards achieving large-capacity, low-cost, high-frequency, reusable space launches in the future.

Image source: CCTV News video screenshot

01 The reusable Suzaku-3 rocket completed a 10-kilometer-class vertical take-off and landing return flight test

This mission is the first time in China to achieve secondary ignition of a vertical take-off and landing return rocket in the air, joint guidance and control of "grid rudder-cooling air attitude control-engine" in a transonic high dynamic pressure environment, and engineering application of high-altitude wind real-time wind repair technology. The test went through the process of "ascent-engine shutdown-unpowered taxiing-engine secondary start in the air-soft landing", and all indicators met the expected design.

According to experts from Blue Arrow Aerospace, the test rocket is a single-stage liquid oxygen-methane rocket with a body diameter of 3.35 meters, a length of 18.3 meters, a takeoff mass of approximately 68 tons, a takeoff thrust of 800 kilonewtons, and is equipped with three sets of landing cushion legs and a new four-piece grid rudder system. It uses the same high-strength stainless steel body structure as the Suzaku-3 rocket. It is equipped with an improved 80-ton Tianque-12 (TQ-12) liquid oxygen-methane engine of the same type as the Suzaku-3 rocket, which has achieved continuous orbital flight verification. It has orthogonal double pendulum, variable thrust adjustment from 45% to 111%, and multiple ignition capabilities.

Image source: CCTV News screenshot

02 Technical highlights of Suzaku-3

(1) Casting a rocket legend in stainless steel?

The Zhuque-3 reusable rocket is my country's first stainless steel liquid carrier rocket. Its tank structure is made of high-strength stainless steel and is highly original in terms of material selection, structural form, welding technology and production equipment.

Compared with aluminum alloy, the material of traditional rocket body structure, stainless steel has low cost and good welding processability, which can greatly reduce the production and manufacturing costs of medium and large liquid rockets. The high temperature resistance of its stainless steel rocket body structure has obvious advantages in rocket reuse. The first-stage engine of the Suzaku-3 rocket does not need to be inspected after the rocket is recovered, and can fly again after refueling, realizing true flight operation.

(2) Liquid oxygen and methane usher in a new era of vertical return technology

In principle, a rocket is actually a power device that uses the propellant it carries to react and generate a high-speed jet of hot air for propulsion. For launch vehicles whose main mission is space transportation, there are four mainstream propellant options for their engines: solid fuel, nitrogen tetroxide/unsymmetrical dimethylhydrazine, liquid oxygen and kerosene, and liquid oxygen and liquid hydrogen.

Nowadays, the main engines of mainstream launch vehicles basically use liquid propellant solutions. Unlike solid propellants, the propellants in this type of solution are divided into two categories: liquid fuel and liquid oxidizer. They are generally stored in two spaces on the launch vehicle engine, and generate thrust after violent reactions after entering the combustion chamber. Among all liquid propellant solutions, liquid oxygen is the oldest oxidizer. In 1926, the first liquid fuel rocket in human history used a solution of liquid oxygen (oxidizer) + gasoline (fuel agent). It is also the most efficient and cheap oxidizer. The main engines of many mainstream launch vehicles use liquid oxygen as an oxidizer, but the difference is the combustion agent that is matched with it. Among them, liquid oxygen + kerosene and liquid oxygen + liquid hydrogen are the most widely used combinations.

Liquid oxygen methane is a rocket fuel made from a mixture of liquid oxygen and methane. Methane is the main component of natural gas and has become a fuel option that rocket engine researchers cannot ignore.

Due to the low cost of liquid oxygen and methane, the methane engine's characteristics of no carbon deposits, easy maintenance and full life cycle monitoring, the first-stage engine of the Suzaku-3 rocket does not need to be inspected after the rocket is recovered. It can fly again after refueling is completed, realizing flight operations, and the launch cost can be reduced by 80% to 90% compared with disposable rockets.

Aerospace experts believe that liquid oxygen-methane rockets have entered a period of rapid research and development worldwide. Faced with future large-scale space travel and flight transportation needs, high-thrust, high-performance, reusable liquid oxygen-methane engines are an important direction for the development of liquid main power.

03 Laying the foundation for the future maiden flight and recovery of Suzaku-3

As early as July 12, 2023, the successful launch of Blue Arrow Aerospace's Zhuque-2 broke the record and became the world's first liquid oxygen-methane rocket to successfully enter orbit, marking a breakthrough in the application of new low-cost liquid propellants for my country's launch vehicles.

On January 19 this year, the first test rocket of Blue Arrow Aerospace's ZQ-3 large-scale reusable liquid oxygen-methane rocket successfully completed its flight test mission at the Jiuquan Satellite Launch Center, laying an important technical foundation for ZQ-3 to achieve its "first flight" in 2025.

The test rocket for this mission is an engineering prototype built with a full-size engine, which is an important part of the development of Blue Arrow Aerospace's reusable rocket project. Through two vertical take-off and landing recovery tests, the model team successfully verified a number of key technologies for reusable rockets, laying the foundation for the future maiden flight and recovery of Suzaku-3.

Comprehensive sources: Xinhua News Agency, CCTV News, etc.