Recently, China successfully launched a reusable experimental spacecraft using the Long March 2F carrier rocket at the Jiuquan Satellite Launch Center. The test spacecraft will operate in orbit for a period of time and then return to a scheduled landing site in China. During this period, reusable technology verification and space science experiments will be carried out as planned to provide technical support for the peaceful use of space.
The reusable technology of spacecraft is one of the focuses in the international aerospace field and an important step in building China into a space power. As a cutting-edge aerospace technology, reusable spacecraft can not only "reduce costs and increase efficiency", but are also expected to make space tourism possible.
Breakthroughs in technological research
A reusable spacecraft refers to a spacecraft that can be used repeatedly, can quickly travel through the atmosphere, travel freely between the earth's surface and space, transport crew members and payloads, and can also refer to a spacecraft that can stay and maneuver in orbit for a long time, complete various tasks Mission spacecraft include manned spacecraft, cargo spacecraft, propulsion vehicles, planetary landers, space shuttles, etc.
On December 14, 2023, China successfully launched a reusable experimental spacecraft. Prior to this, China had launched reusable spacecraft on September 4, 2020 and August 5, 2022. Among them, the reusable spacecraft launched in 2022 successfully returned to Earth after flying in orbit for 276 days, marking an important breakthrough in China's research on reusable spacecraft technology, which will provide a more convenient and cheaper round-trip method for the peaceful use of space.
Hao Chun, director of the China Manned Space Engineering Office, previously said that in order to further improve the comprehensive capabilities and technical level of the project, China will develop a new generation of manned launch vehicles and a new generation of manned spacecraft. Among them, the return capsule of the new generation manned launch vehicle and the new generation manned spacecraft can be reused.
At the end of last year, the U.S. X-37B "Orbital Experimental Vehicle" successfully entered space aboard the "Falcon Heavy" launch vehicle and carried out its seventh mission. The X-37B aircraft first flew in 2010. It was manufactured by Boeing Company in the United States. It is about 9 meters long and has a wingspan of about 4.6 meters. It is similar in appearance to a space shuttle, but its volume is only 1/4 of the space shuttle. Part of its power supply comes from solar energy. This aircraft is equipped with an automatic landing system and is sent into space by a rocket. When it returns, it will glide and land on a runway like an airplane. It can be reused but does not carry people. The aircraft can perform communications relay, ground observation and other tasks, and has a wide range of military and civilian uses.
Solve cost and capacity issues
Reusability is also the only way for the development of launch vehicles and will become an important way for humans to enter and exit space on a large scale. In recent years, China has carried out technical research on reusable launch vehicles based on the technology of disposable launch vehicles and has made positive progress.
On July 16, 2021, the suborbital reuse demonstration and verification project vehicle developed by the First Academy of China Aerospace Science and Technology Corporation successfully made its first flight at the Jiuquan Satellite Launch Center. On August 26, 2022, the reusable flight test of the lift-type suborbital launch vehicle independently developed by the China Academy of Launch Vehicle Technology was successful.
The suborbital reusable launch vehicle can be used as a sub-stage of the lift rocket-powered reusable space transportation system and is a highly integrated aerospace technology. These successful flight tests have effectively promoted the leapfrog development of China's space transportation technology from one-time use to reuse, and laid a solid foundation for the development of reusable space transportation technology between space and earth.
Disposable launch vehicles have long been the main mode of transportation for humans to enter space. Why should we develop reusable launch vehicles? Bao Weimin, academician of the Chinese Academy of Sciences and director of the Science and Technology Committee of China Aerospace Science and Technology Corporation, pointed out that with the rapid growth of the demand for space entry and exit, disposable launch vehicles are facing huge challenges in terms of launch costs, performance cycles and production capacity requirements. The development of reusable launch vehicles Launch vehicles can solve the above problems very well.
Bao Weimin said that on the whole, reusable launch vehicles have obvious advantages over disposable launch vehicles in terms of launch cost and launch frequency, and are the ideal way to achieve large-scale, low-cost space entry and exit such as global arrival in one hour and round-trip transportation between space and ground. important means of transportation system.
Form a variety of technical solutions
As early as the 1950s and 1960s, humans have begun to explore technologies related to reuse of space transportation systems. After decades of development, major aerospace powers and regions have possessed varying degrees of reusable technology reserves, forming a variety of typical reusable carrier solutions. Among them, according to the number of orbit entry stages, it can be divided into multi-stage orbit entry scheme and single-stage orbit entry scheme; according to the take-off and landing method, it can be divided into vertical take-off and landing scheme, vertical take-off and horizontal landing scheme, and horizontal take-off and landing scheme; according to the recovery method , can be divided into partial reuse scheme and complete reuse scheme.
At present, rocket engine technology is relatively mature and is the preferred propulsion method, while combined power is an important development direction in the future. The first stage of the rocket-powered two-stage orbit reusable space transportation system is the focus of domestic and foreign reuse technology.
The "Falcon 9" of the American Space Exploration Technology Company is a reusable launch vehicle. It uses the low-cost advantage brought by reuse to develop rapidly in the global commercial space launch market. In the past year, Falcon 9 has been launched more than 30 times. Recently, the "Falcon 9" rocket and the "Dragon" spacecraft carried a "private" space team organized by the American private company Axiom Aerospace to the International Space Station.
In the field of private aerospace, Chinese aerospace companies have also successively developed reusable launch vehicles in recent years. Recently, the Kuaizhou rocket reusable technology test arrow independently developed by China Aerospace Science and Industry Corporation's Sanjiang Rocket Company successfully completed its vertical take-off and landing test, laying the foundation for the development of the Kuaizhou series of reusable liquid oxygen methane launch vehicles. Not long ago, the Zhuque-3 reusable rocket's vertical return technology completed its first flight test at the Jiuquan Satellite Launch Center. The rocket is China's first stainless steel liquid launch vehicle and uses liquid oxygen and methane as fuel. The Zhuque-3 rocket body has a diameter of 4.5 meters, and one sub-stage is designed to be reused no less than 20 times. It has the ability to launch multiple satellites with one rocket and flat-plate stacked satellite clusters. The Suzaku-3 tank structure is made of high-strength stainless steel, and the launch cost can be reduced by 80% to 90% compared with disposable rockets.
Reusable spacecraft have the technical characteristics of low cost and high reliability, and can meet the future development needs of cheap and free access to space. In addition to replenishing systems such as the space station with personnel and supplies, reusable spacecraft can also carry passengers, enabling more efficient space travel at a lower cost.
In the future, during space travel, the power system of the reusable vehicle will continue to use rocket engines. The take-off stage is like a rocket launch, climbing to a suborbital space about 100 kilometers away from the earth, staying for about 10 minutes, and then relying on inertial imaging. The plane returns to Earth and lands horizontally. The whole process takes about 30 minutes, and the whole process is in accordance with the predetermined procedures and the flight is fully automatic. Tourists do not need to wear spacesuits, and can even bring their mobile phones to take photos and post them on WeChat Moments, floating around in the cabin like astronauts, and looking at the Earth from space through the windows. Since the launcher itself has an error correction function, it can return to the correct track even if the instructions are wrong. Therefore, tourists also have the opportunity to experience the fun of space driving.
Reusability, high reliability and high safety are important development directions for future spacecraft. Currently, there are still many challenges in the development of reusable spacecraft. For example, spacecraft require advanced thermal insulation protection when re-entering the atmosphere, as well as a sturdy and reliable landing system and a reliable and efficient propulsion system. At the same time, maintaining the power source while the spacecraft is in orbit also requires advanced solar panels or other power generation systems that can operate reliably in space. (People's Daily Overseas Edition Reporter: Liu Wei)