Recently, Elon Musk said he would launch 1000 spacecraft to transport 10 million people to Mars. Because Mars is the only planet in the solar system other than Earth that may be suitable for life, some countries have proposed many manned Mars exploration programs and made a lot of technical reserves. Moreover, 3 probes landed on Mars this year, setting off a “Mars fever” again. So how will human beings land on Mars in the future?
Facing multiple technical tests
The process of manned Mars exploration missions is very complicated. It can be roughly divided into stages such as Earth surface launch, Earth orbit assembly, earth fire transfer, Mars landing and rise, Mars orbit rendezvous docking, return to Earth, etc. Each stage faces major technical challenges.
The distance between Earth and Mars is far away.
Mars is very far away from the earth. Every 26 months, there will be a reversal window between Mars and Earth. The nearest distance between the two is 5500 million kilometers, up to 4 billion kilometers. Manned spacecraft go to Mars for at least 6 months one way, and then consider the launch window to return from Mars. Astronauts may need to work on the surface of Mars for nearly 500 days, so a single manned Mars exploration mission may last up to 900 days. During the long space journey in the past 3 years, astronauts can hardly get a second supply of supplies, so manned Mars exploration missions need to carry a lot of supplies and energy.
Considering that astronauts need to work and live on the surface of Mars for a long time and the rise and return devices that take off from the surface of Mars, humans need to transport at least 40 tons of materials to the surface of Mars. In addition, carriers such as ground fire transfer vehicles, residential living cabins used by astronauts on the surface of Mars, manned spacecraft and other carriers are expected to approach 1000 tons of mission mass are launched into orbit.
Such a huge launch mass far exceeds the current rocket’s carrying capacity, which requires launching each module into Earth orbit in batches, assembling and assembling in Earth orbit, and then flying to Mars. This involves technical problems such as the overall scheme design of manned Mars exploration, orbit optimization, low-temperature propellant storage and management, and orbit assembly.
Imagination of human landing on Mars by spacecraft
The journey of Mars exploration is long. Astronauts live in radiation and microgravity environments for a long time. They need to study food nutrition maintenance and long-term storage technology, radiation protection technology and equipment, medical diagnosis and treatment equipment, and also encourage astronauts to carry out activities in a narrow environment to relieve physical and psychological pressure and provide weeks. Comprehensive health protection measures.
In addition, long distances cause communication difficulties. Two-way communication between Mars and Earth will be delayed by 6-44 minutes. New communication network links need to be established to maintain reliable communication.
There is a delay in communication between Earth and Mars.
In the process of entering Mars orbit and landing, due to the thin atmosphere of Mars, a large amount of aerodynamic heating will occur when the lander flies at hypersonic speed, which requires the application of thermal protection technology.
At the same time, due to the thin atmosphere of Mars, the effect of the parachute is not obvious when landing, and it is necessary to use innovative technology of reverse thrusters to slow down.
In addition, due to the long delay, it is difficult for Earth workers to provide relevant support for the process of landing on Mars, which also puts forward higher requirements for the autonomy, reliability and safety of manned Mars exploration, and more advanced guidance and control technologies must be developed.
Composition of manned Mars exploration system
In order to complete the manned Mars exploration mission, the future exploration system will include unmanned exploration system, space transportation system, Mars surface application system and measurement and control system.
The unmanned exploration system mainly includes Mars orbiters, unmanned rovers and radio beacons that were put into Mars in the early stage of the mission, which are used to investigate the Martian environment explored by astronauts, select astronaut landing sites, carry out technical verification and radio navigation, etc.
Space transportation systems include various carriers for different stages of manned Mars exploration missions, including launch vehicles, geofire transfer stages, Mars landing and risers, Mars ground facilities, etc.
Among them, the launch vehicle sends all mission payloads and astronauts into Earth orbit, and the ground fire transfer stage is responsible for the transfer between Earth orbit and Mars orbit, sending astronauts and materials into Martian space.
It’s not easy for manned spacecraft to land on Mars.
Landing and ascending devices are mainly responsible for the round-trip transportation of people and materials between the Mars orbit and the Mars surface. They are generally composed of two-stage aircraft. The propellant can be produced using Martian resources and some of the carrying resources after reaching the surface of Mars.
In order to ensure the transportation mission between the surface of Mars and the orbit, some infrastructure needs to be built on the surface of Mars, including in-situ resource utilization equipment, energy systems, landing guidance systems, and launch sites. Among them, in-situ resource utilization equipment can use Mars’ own resources to produce energy, propellants, etc.
Mars surface application systems include residential cabins, scientific experimental modules, environmental protection systems, Mars rovers, extravehicular activity systems and power systems. Among them, the environmental control life insurance system is used to ensure the living conditions of astronauts, and the Mars rover helps astronauts move and explore quickly on the surface of Mars.
The TT&C system includes ground TT&C systems, which include various TT&C networks on the ground, and space-based TT&C systems, and space-based TT&C systems, the latter includes relay satellites, navigation and communication satellites. The measurement and control system can ensure the communication between Mars surface equipment and Earth researchers, transmit experimental data, and let Earth researchers intervene in the disposal of Mars surface equipment problems.
Astronauts’ ground fire round trip process
For a long time, the United States, Russia and others have been actively studying the feasibility of manned Mars exploration missions and putting forward a number of scheme ideas. In summary, the process can be roughly divided into several stages.
The first stage is the transshipment of materials. The launch vehicle sends payloads such as ferry stage, cargo transfer stage components, Mars landing and riser, Mars surface facilities into low-Earth orbit in batches and assembles them into cargo transfer stage in orbit. After the ferry stage transfers the cargo transfer stage to high-Earth orbit, it returns to low-Earth orbit. Then launch a refilled vehicle by a carrier rocket to in orbit the ferry stage, waiting for the next ferry mission.
Manned spacecraft to Mars
The cargo transfer stage passes through the geofire transfer orbit. After a long journey, it enters the ring fire orbit, waiting for manned spacecraft and astronauts. At the same time, it releases Mars surface facilities, lands on the surface of Mars, and prepares propellants.
In the second stage, payloads such as manned transfer stage components and deep space residential cabins are transported to low-Earth orbit in batches by launch vehicles, manned transfer stages are assembled in orbit, and they are transferred to high-Earth orbit by ferry stages.
Once the surface facilities of Mars and the manned transfer stage waiting in high-Earth orbit work well, and wait for the appropriate launch window, the launch vehicle launches the manned spacecraft into the predetermined orbit, docks with the manned transfer stage, and then sends the astronaut into the geofire transfer orbit by the manned transfer stage.
In the third stage, the manned transfer stage enters the ring fire orbit. The manned spacecraft docks with the Mars landing and ascendor that had previously entered the ring fire orbit. Astronauts enter the Mars landing and riser, land on the surface of Mars, and carry out operations and scientific exploration activities.
In the fourth stage, after completing the Mars surface mission, the astronauts inject propellant into the Mars landing and ascendor, ride the riser, return to the ring fire orbit, and complete the docking with the manned transfer stage waiting for the ring fire orbit.
Finally, the manned transfer stage enters the fire transfer orbit and returns to Earth space.
It should be pointed out that at present, some of the technologies of manned Mars exploration missions based on conventional propulsion systems have been verified. With adequate budget support, human beings can gradually land on the surface of Mars. However, the long mission time has caused the scale of the exploration system, which is concerned about the current level of human engineering technology and the astronauts. Both reason and physiology cause great pressure. If the time of manned fire detection missions is to an acceptable level, many revolutionary advances are needed in space engineering, especially nuclear thermal propulsion systems.
I believe that with the continuous improvement of space technology capabilities, human beings will eventually land on Mars, become a cross-planetary species, and gain a wider space for development.