【Text/Observer Network Zhao Noah】Nuclear thermal propulsion rockets, ladders, Earth-Mars economic circle... These terms, which previously appeared only in science fiction works, have been incorporated into the blueprint of China's future Mars plan.
Recently, the 2021 Global Space Exploration Conference (GLEX 2021) was held in Russia. Affected by the epidemic, China participated in the meeting through online means.
During the meeting, Wang Xiaojun, president of the China Academy of Launch Vehicle Technology (First Academy of Astronautics), delivered a speech entitled "Manned Mars Exploration Space Transport System", which not only introduced China's previous Achievements in Mars Exploration Missions, but also revealed China's future manned Mars exploration development route.
Taken as a whole, this idea is divided into three steps: the first step is robotic Mars exploration, including sampling, base selection and in situ resource utilization. The second step is primary manned exploration, which aims to land on manned Mars and base construction; the final step is to explore flights and establish an Earth-Mars economic circle.
In order to achieve this Mars plan, the China Academy of Launch Vehicle Technology has basically determined the composition, characteristics, overall scheme and design parameters of the space transport system for manned Mars exploration missions. Compared with the existing space transport system, the Mars exploration project requires a more complex transport system, and the transport will also change from chemical propulsion to thermonuclear and even nuclear fusion propulsion.
Wang Xiaojun believed in his speech that there are still many technical problems in the realization of manned Mars exploration and space transportation, but he said: "Mars exploration is of great significance to mankind, it is an important way for human beings to go out of the cradle of the earth, explore the origin of life, and expand the living space. We are willing to work with our counterparts and partners at home and abroad to jointly realize the dream of human beings going to deep space and walking on Mars. ”
Wang Xiaojun brings a speech on "Manned Mars Exploration Space Transport System" to global astronauts in the video Screenshot (the same below)
To establish a "geo-fire economic circle", China plans to take three steps
From June 14 to 17, the 2021 Global Space Exploration Conference was held in Russia. Affected by the epidemic, China participated in the meeting through online means and brought speeches to the space professionals and media from various countries attending the meeting. On the second day of the conference, Wang Xiaojun, as the representative of the Chinese side, told the history and future of China's exploration of Mars from the perspective of space transportation and rocket technology.
However, the media and professionals are more concerned about Wang Xiaojun's plans to establish a sustainable base on Mars and even the Earth-Mars economic circle in the future, which Wang Xiaojun revealed in the lecture. For example, the well-known space news professional website "space.com" in the United States specially pulled out this plan and reported it.
Space.com: China wants to build a sustainable presence on Mars
Wang Xiaojun's speech was divided into four parts: the structural analysis of the manned Mars exploration mission, the development route of the manned Mars exploration, the overall transportation system concept, and finally the key technical difficulties.
In the first part, Wang Xiaojun said that the factors affecting the design of the mission structure are the type of ground fire transfer track, the departure time, the starting point, the propulsion technology, and whether to use aerodynamic capture.
He proposed that the appropriate departure time for Mars missions is 2033, 2035, 2037, 2041, 2043, etc., and it is more appropriate to choose a high elliptical orbit (HEO).
In terms of propulsion technology, nuclear thermal propulsion is an important choice for the design of the current manned Mars exploration scheme. Nuclear fusion propulsion theoretically has higher specific impact performance, which requires theoretical and technological breakthroughs and is suitable as a longer-term research target for manned Mars exploration. In addition, China is also studying the new transportation system of the ladder as a space starting point, which can reduce the scale of Mars exploration and transportation.
In the second part, he proposed a three-step plan for China's manned Mars exploration.
The three-step plan proposed by the Chinese side
The first step is the robot Mars exploration, which mainly performs the Mars sample return, the Site Selection Investigation of the Mars Base, the utilization and construction of in situ resources, etc., which belongs to the stage of technical preparation.
"Space.com" explains that the use and construction of in situ resources refers to pumping water from under the surface of Mars or obtaining oxygen directly from the surface of Mars to compensate for the replenishment limits of Mars exploration. The purpose of the Chinese plan is to build a platform for the initial manned Mars mission, starting from the orbital outpost, in preparation for landing on Mars and eventually for the establishment of a Mars base.
The second step is the initial manned exploration, which mainly includes manned ring fire orbit exploration, manned Mars landing exploration, and Mars base construction.
The third step is the flight detection, which is the stage of the formation of the economic circle, mainly including large-scale fire transport fleet, large-scale (Martian resources) development and application.
Wang Xiaojun proposed a corresponding space transport technology roadmap for each step. For example, in the robot Mars exploration stage, China uses large or heavy launch vehicles to directly launch the probe into the ground fire transfer orbit. The probe uses chemical propulsion, selects a pulsed combined orbit, and uses reverse thrust braking to reach Mars for exploration.
In the initial stage of manned exploration, China designed a new mission structure for orbital transfer, which uses nuclear power nuclear thermal propulsion combination, human and cargo diversion, assembled in near-Earth orbit (LEO), starting from high orbit, and using Mars aerodynamic capture.
Conceptual diagram of an initial Mars manned planned transport system
He explained in detail that during this phase, the cargo transfer stage rocket and payload were first transferred by the carrier rocket to low Earth orbit, and the cargo transfer stage (rocket) was loaded in the orbit group. The Geospatial Ferry class ferries the cargo transfer class to the Earth's high orbit and then returns to low Earth orbit.
Subsequently, the cargo transfer stage ignites into the ground fire transfer orbit, employs atmospheric capture and low fire braking, enters the ring fire orbit, and the Mars landing and ascent period (MDAV) waits for the members to arrive in the ring fire orbit. At the same time, release the Martian surface facilities and land on the Surface of Mars.
Arrive at the manned transfer window, the manned rocket is directly launched into the high orbit, docking with the manned transfer stage, and the manned transfer stage ignites into the ground fire transfer orbit. The manned transfer class close-fire brake enters the ring fire orbit, and the members land on the surface of Mars through Mars landing and ascent vehicles to carry out Mars surface operations.
On the return journey, the members enter the landing and ascent, return to the ring fire orbit, dock with the manned transfer level waiting on the ring fire orbit, and then enter the fire transfer orbit from the manned transfer level, and finally return to Earth.
In the final stage of manned Mars exploration, the Chinese side proposed to adopt a nuclear power integrated transportation mode, starting from the earth space station, the Sun-Ground L2 and other bases, selecting the geo-fire cycle orbit, the ground-fire cycle orbit has been arranged to transfer the aircraft, and the propellant of the transfer vehicle will be replenished by the ground or space filling station.
Conceptual diagram of a transport system for the phase of a manned Mars exploration of flights
"Manned Mars exploration and transportation systems are very different"
Wang Xiaojun said that compared with the earth space launch vehicle flying into space at one time, the manned Mars exploration and transportation system is very different. Its mission structure includes: entering the Earth orbit, assembling the Earth orbit, earth fire transfer, Mars landing and ascent, Mars orbit docking and return to Earth, etc.
In addition, the flight time of manned Mars missions may reach hundreds of days, the flight distance can reach millions to hundreds of millions of kilometers, and the number of orbital rendezvous and docking times has reached more than 10 times.
To this end, the specific parameters of the task proposed by the Chinese side are:
Earth ascending segment: 7 heavy launch vehicles and 1 manned launch vehicle, using chemical propellants.
Geospace Ferry Geothermal Transfer Stage: Ferry class based on high specific impulse nuclear power propulsion technology, and ground fire transfer vehicle based on high specific impulse high thrust nuclear thermal propulsion technology.
Mars Space: Mars Landing and Ascent Vehicle Based on Chemical Propulsion.
Ground fire transfer carrier: Using nuclear thermal nuclear power dual mode, three 10-ton thrust nuclear thermal engines as the main power, the use of nuclear power systems to provide power for each subsystem.
Manned transfer vehicle: with a total mass of 246 tons and 108 tons of liquid hydrogen, it can carry a total of 65 tons of payload, including deep space living modules and manned spacecraft.
Cargo type transfer vehicle: the total mass is 328 tons, the filling is 76 tons of liquid hydrogen, and the payload mass is 206 tons.
Of course, China's Mars program still has many key technical problems. Wang Xiaojun said that these problems mainly include the overall design technology of the space transport system, the propulsion technology of large-scale interstellar transport, the precision guidance and control technology, the energy and interstellar measurement and control communication network technology, and the lightweight heat-proof structure design technology.
China Academy of Launch Vehicle Technology (also known as the First Research Institute of China Aerospace Science and Technology Group Co., Ltd.), founded on November 16, 1957, affiliated to China Aerospace Science and Technology Group Co., Ltd., is the birthplace of China's aerospace industry, and the longest and largest missile weapons and launch vehicle development, test and production base in China.
Tianwen-1 probe landing platform National Space Administration map
The "Space.com" interpretation said that the plan proposed by Wang Xiaojun is "ambitious", but it is also in a very early stage. In addition, the plan does not take into account other challenges of human long-distance travel into deep space, such as radiation and the effects of a gravity-free state. But the plan does include some technologies already under development, such as a new generation of manned spacecraft, and other Chinese space agencies will try to solve other challenges beyond the transport system.
At present, the world's major space agencies studying Mars settlement programs include NASA, the European Space Agency (ESA) and the Russian Federal Space Agency (Roscosmos). But at present, NASA's Mars exploration plan is mainly based on the Artemis moon landing plan, and has not proposed a complete Mars settlement plan.
It is worth mentioning that at this conference, the China National Space Administration and the Russian State Space Corporation also jointly issued the "Roadmap for the International Lunar Research Station (V1.0)" and the "Guide for the Partners of the International Lunar Research Station (V1.0)", which introduced the concept, scientific field, implementation path and cooperation opportunities of the International Lunar Research Station, and pointed out the direction for the participation of international partners in the planning, demonstration, design, development, implementation and operation of the International Lunar Research Station.
According to the Guidelines, the project has set 8 major scientific objectives related to the moon; from 2021, the project construction will be divided into three phases of "exploration, construction and use", with a time span of 15 years, which is planned to be completed in 2035; and the project also delineates five types of cooperation for the participation of international partners at each stage and at all levels of the stage.
After the release of this document, China and Russia will also launch an updated version of the Roadmap and the Guide in due course, further clarify the milestone plan of each engineering stage of the International Lunar Research Station, and release the partner joining procedure in a timely manner to ensure the steady progress of the overall project.