The idea of immigrating to Mars

Recently, Space Exploration Technology Company has released a blueprint for a new generation of rockets: the next generation of heavy-duty launch vehicles called "starships" will become the largest space carrier in human history.

At the launch of the new plan, Space Exploration Technology Company exhibited the completed full-scale prototype MK 1 of the second phase of the starship. Elon Musk, the founder of Space Exploration Technology Company, said in a speech that Space Exploration Technology Company plans to conduct the unmanned flight test of MK 1 this year. In addition, the prototype MK2 is also under construction, followed by MK3 and MK4 ... Space Exploration Technology Company is sparing no effort to promote the starship program.

According to the official website of Space Exploration Technology Company, "Starship" will be used to go to "Earth orbit, the moon, Mars and beyond". Musk has repeatedly stressed that his goal of creating a space exploration technology company is mainly to help humans immigrate to Mars. Judging from the design parameters of the starship, it is obviously aimed at this goal. Then, will the strongest transportation capacity in history, the most engines in history, orbital refueling and rocket reuse ... will these black technologies that challenge the limits of human science and technology be realized? Will the human Mars program become a reality?

Iterative starship moves from imagination to reality.

On the homepage of the official website of Space Exploration Technology Company, four projects are displayed side by side. The first two projects are Falcon 9 and Falcon Heavy, two active launch vehicle projects, and the third project is Dragon Spacecraft, which is a "transport plane" of Space Exploration Technology Company. It has successfully transported materials to the International Space Station and will be upgraded to a manned spacecraft next year to transport astronauts to the International Space Station. The last project belongs to the future. It has a sci-fi name-"Starship".

According to the concept of space exploration technology company, the engine room of the starship can accommodate 100 people, and its first-class "super heavy" also has unprecedented super thrust. Musk commented in September that the "Starship" system will be the fastest way for humans to build a self-sustaining city on Mars.

Known as a "madman", Musk has repeatedly stressed that his goal of creating a space exploration technology company is mainly to help human beings immigrate to Mars: in 20 16, Musk announced the design concept of "Interstellar Transportation System" (ITS), which will be specially used for transportation between planets in the solar system. Musk said at that time that his final plan was to transport 1 000 people to Mars every 26 months, with the goal of building a city with a population of one million on Mars within 50- 1 000 years.

Space exploration technology companies are also repeatedly adjusting the names of designs and systems. For example, 20 17, ITS was renamed BFR (large falcon rocket), and the design index was also reduced. Later, the project was renamed BFR, and the design was constantly updated, almost returning to the original level.

2065438+September 2008, Space Exploration Technology Company announced the first passenger to buy a "boat ticket" for BFR's flight around the moon-Japanese rich Tomoko Maezawa. He plans to go to the moon in 2023.

On October 2018165438+10, Space Exploration Technology Company announced that the BFR plan was officially renamed as "Starship". In this transportation system, the first stage/booster is called "super heavy" rocket, and the upper stage/spacecraft is called "starship". The system composed of the two is also collectively called "starship".

It's amazing that the "Starship" entered the reality so quickly. Space Exploration Technology Company quickly produced and tested several "starship" prototypes, including the full-scale prototype MK 1.

Time goes back to 2065438+July 2009. Space Exploration Technology Company conducted a free suspension test on Starhopper prototype at Bokachica proving ground in southern Texas, USA, creating a new record of flying height150m.

20 19 At the end of September, Space Exploration Technology Company exhibited the full-scale prototype MK 1 of Starship at the press conference. This 50-meter-high and 9-meter-diameter giant spacecraft is equipped with three raptor engines, flying higher than Starworm. At the press conference, Musk said that MK 1 will probably conduct a test flight at a height of 20 kilometers after 1 month.

Another prototype, MK2, is also in production, and the off-line time is expected to be later than MK 1. MK3 and MK4 are expected to be completed within six months and make their first orbital flight. MK5 is also planned.

Pang Zhihao, chief science communication expert of national space exploration technology, also said that space exploration technology company has changed the technical parameters of the "Starship" project many times, showing that its technology is far from mature, but it boldly adopts new technologies and schemes, and is not afraid of failure, and is constantly improving in practice. This practice is worth learning.

Historically, the first stage rocket had at most 37 engines.

Musk introduced at the space exploration technology company meeting that the upper stage of the starship system is 50 meters high, 9 meters in diameter and 200 tons in dry weight, and it is expected to be optimized to 120 tons in the future. Equipped with six Raptor engines, the carrying capacity of near-earth orbit will eventually reach 150 tons; The weight of the load returned to the earth is 50 tons, and the propellant filling amount is 1200 tons. The cabin space of the starship is 1 100 cubic meters, which can carry 100 people.

The index of the first-class "super heavy" rocket is even more exaggerated. It is 9 meters in diameter and 68 meters in height. It is equipped with 37 Raptor engines, with a takeoff thrust of about 7,500 tons, twice that of Saturn V, the rocket used in Apollo's manned moon landing program, and the highest thrust rocket in human history. Now he's retired.

The first phase of 37 engines is also a record. At present, Space Exploration Technology Company's Falcon Heavy is the world's most powerful launch vehicle, with 27 Merlin engines working in parallel at launch.

At that time, before the launch of Falcon Heavy, the outside world expressed concern about this "insufficient thrust and quantity" rocket working mode. Twenty-seven Merlin engines work in parallel, which may explode due to * * * vibration in flight, which was once one of the biggest technical challenges of this type of rocket. Musk himself said that as long as the rocket did not explode on the launch pad, it was successful. Fortunately, the Falcon was successfully launched. Previously, in order to achieve manned landing on the moon, the Soviet Union adopted a first-stage rocket design with 30 engines working in series, but all four launches failed.

"It is really risky for multiple engines to work together. If one or two engines fail, the engines symmetrically arranged with them will not shut down smoothly, or even explode once, the whole rocket will be destroyed. " Mao Xin is willing to say.

"For example, the N 1 rocket is not completely infeasible in theory, but the key is that in order to use so many engines at the same time, many auxiliary facilities are needed, including various fuel supplies, electronic circuits and structural control systems. For example, how to design a system to distribute fuel reasonably through the pump cycle and how to turn on and off the control systems of these engines need to be well coordinated. " Mao Xin would like to introduce.

Space exploration technology company has rich experience in designing multi-engine rockets. Mao Xin wants to say that Space Exploration Technology Company has proved the feasibility of the technology through its own practical examples. "The first stage of the Falcon heavy rocket has 27 Merlin engines, and several launches have been very successful."

"Space Exploration Technology Company has conducted in-depth research on the distribution, control system and auxiliary system of rocket fuel system. Especially when the first stage/booster of Falcon rocket is recovered, nine engines do not work together, but work step by step according to different quantities. This reflects a very high level of rocket engine control. " Mao Xin wants to say that the first stage of the "Starship" consisting of 37 engines is feasible and will not become a technical bottleneck.

In addition, Mao Xin would like to mention that the design of Space Exploration Technology Company also has advantages in cost. "Small engines can be mass-produced, and the cost is much lower than using several large engines. In addition, the' starship' can also be recycled, so the current solution is also what space exploration technology companies can do based on existing technologies, even the best solution. "

"Space refueling" makes the spacecraft go further.

Maybe we will see the launch of the starship soon. Space Exploration Technology Company said that the first flight of Starship will be realized in 20021year, but the early flight will be unmanned and may be used for launching communication satellites.

As for going to the moon and Mars, it is necessary to "refuel in space". At the press conference, Musk introduced the "orbital replenishment" plan of "Starship" in detail. It is envisaged that the manned spacecraft will first fly to Earth orbit for standby, and then launch a second spacecraft loaded with fuel as a "tanker". The two spacecraft will meet to transfer and refuel fuel in orbit, and then the manned spacecraft will go to the moon or Mars. Musk said that the docking of the "Starship" is simpler than the docking of the "Dragon" spacecraft and the International Space Station. "This is another key to establishing a base on the moon or Mars."

Mao Xin would like to comment that "space refueling" technology is very difficult. On the one hand, launching any load into space is very complicated; On the other hand, it is technically difficult to carry out large-scale liquid transportation in a weightless environment.

However, Mao Xin would like to think that "space refueling" is very important for human "navigation". "Realizing' space refueling' means that the cost can be greatly reduced. For example, fuel can be continuously replenished through multiple tasks, so that the huge load required for a single task can be dispersed, and the overall cost can be reduced and the success rate can be improved. "

Anyway, I'm afraid it will be a long time before we land on Mars.

According to NASA's previous plan, the US government-led manned mission to mars is expected to be launched in the mid-1930s, while Musk's plan is much more radical, claiming to land on Mars in 2024. However, in view of the consistency of long-term planning of space exploration technology companies, few people take the 2024 Mars program seriously.

"According to the existing blueprint, it is no problem for the' Starship' to leave the Earth for more mature lunar exploration and preliminary Mars exploration." Mao Xin wants to say, "But it is still very difficult to challenge manned landing on Mars."

Mao Xin wants to say that an important challenge of manned landing on Mars is how to return. "Considering the atmospheric resistance of Mars, how to land and how to return is an almost impossible task for humans including the' starship'."

"If you challenge manned landing on Mars, you need to do a lot of other technological development, and even produce rocket fuel on Mars, because it is very unrealistic to take it from the earth. This also means huge capital costs and technical challenges, which even a single country like the United States, the Russian Federation and China is unlikely to complete. " Mao Xinyuan said, "This can be regarded as a grand plan of mankind, but at present, mankind is far from this step."