For Xu Chuan, sending the space shuttle into outer space is just the most basic goal in the development of space technology.

His goal is to realize the transportation of Earth-Moon resources, and even the colonization between Earth and Fire.

And the foundation of all this is built on mature and high-speed space technology.

However, this can be said to be a 'luxury' for the current space technology.

For example, the Apollo 1 lunar spacecraft took more than eight days to travel from Earth to the moon, let alone back.

It has to do with how it is launched, how it is launched, and how it is launched.

When the Apollo lunar spacecraft was launched, the spacecraft did not directly accelerate into the Earth-Moon transfer orbit segment, but made various orbit maneuvers to go to the moon.

Its entire flight process can be divided into four orbital segments: the orbital segment entering the earth, the orbital segment orbiting the earth (also known as the reversing orbit segment), the Earth-Moon transfer orbit segment, and the orbital segment orbiting the moon.

First, the astronaut needs to take off from the danger center on the ground on a rocket and then enter the Earth's orbit, and this time is 16 hours.

After orbiting the Earth, the vehicle will ascend to another orbit, farther away from the Earth and closer to the Moon. In this orbit, the vehicle needs to fly for another 24 hours before it can perform the next maneuver.

This is the first time that the orbital segment has been turned into.

Subsequently, the plane again ascended to a 48-hour orbit, which was the second turn to orbit.

After flying around the earth twice, it still can't fly directly to the moon, and it still needs to ascend to orbit in a 48-hour cycle, and do a third orbit adjustment, so as to move away from the earth and approach the moon in a larger range.

After completing three orbit changes, the spacecraft can begin to accelerate to the moon. This process takes about 5 days, which is 120 hours.

As it approaches the moon's orbit, it is captured by the moon's gravitational pull.

After entering the lunar orbit, the spacecraft will stay in an orbit of 200 kilometers from the moon and begin to slow down.

After the deceleration is completed, a safe landing on the lunar surface can begin.

Before and after, all kinds of complex orbit changes, various orbital movements, and the entire flight process took more than eight days to finally complete a moon landing, which shows the great difficulty of landing on the moon.

And that's just the Moon, where the average distance between the Earth and the Moon is only 380,000 kilometers.

If it were to land on Mars, the average distance between Earth and Mars would be as high as 55 million kilometers, even in the closest period.

Such a long distance can take more than a month or two months.

Judging from the current space technology, it will take at least half a year to reach Mars from Earth.

For others, this time can be quite short.

But for Xu Chuan, this time is a bit too long.

It takes half a year to complete a fire, and with the current space technology, it will take a hundred years to establish a scientific research base or colonize Mars.

In the office, in the face of this problem, Academician Chang Huaxiang couldn't help but speak: "I said that your heart is a little too big, we haven't gone to the moon yet, and you are thinking about landing on Mars." ”

Xu Chuan took a sip of the tea in the cup, smiled and said, "Although it is difficult for us to land on the moon, it is not out of reach, is it?" ”

"If it is just to land on the moon, it is not much of a challenge for me, and it is not worth my time and energy to lead this work, I believe that there are enough talents in the domestic aerospace field to take on this mission."

In fact, for Xu Chuan, the moon landing was not his goal, and even the fire was not his goal.

In his mind, there was a bigger plan than the two, but there was no need to say it.

After all, if that idea is spoken, the whole society at present, I am afraid that there is not one in 10,000 people who can understand and support it, at most it is just adding some talking points to people who think he is crazy.

On the sofa, listening to Xu Chuan's words, Chang Huaxiang said with emotion: "You young people still have ideas, goals, and bottlenecks, and I don't know if I can see it in my lifetime." ”

sighed, and the academician immediately thought about it.

After a short while, he spoke: "If you want to shorten the time to go to the moon or the fire, there is no way. ”

"How?"

Chang Huaxiang thought for a while and said, "If you want to shorten the time, there are two most effective ways. ”

"The first one is to increase the speed of the spacecraft by using fuel (working fluid) in the thrusters, and you know very well that the faster the spacecraft, the shorter the time to go to the moon and Mars."

"However, this has extremely high requirements for the performance of spacecraft or space engines, as well as fuel."

Hearing the first solution, Xu Chuan thought about it briefly and understood the thoughts of this academician Chang Huaxiang.

It is well known that in the case of a fixed distance, regardless of other factors, the faster the speed of progress, the shorter the time of demand.

When traditional manned spaceflight goes to extraplanets such as the moon and Mars, it almost always maintains an even speed on most of the road.

For traditional fossil fuel rockets, this is almost impossible to break through.

Because the thrust-to-weight ratio restricts everything, it is impossible for landers and spacecraft to carry large amounts of fuel to do this.

Conventional spacecraft cannot afford to leave a lot of space and weight to carry fuel, whether in terms of design, functionality, or their own load and launch weight.

And every track change, acceleration, deceleration and other links require a large amount of fuel to complete.

This also limits humanity's ability to explore other planets.

After all, if you want to recover the probe or send the astronaut over and back again, the endurance of the spacecraft is the biggest problem.

However, for the space shuttle, which uses miniaturized and controllable nuclear fusion technology as an energy source, there is no need to worry about energy at all.

Deuterium-tritium fusion releases thousands of times more energy than fossil fuels burn, and one ton of deuterium-tritium raw material is enough to complete a manned landing on the moon.

Compared with fossil fuels, although some of the liberated space will be used for the storage of aerospace working fluids, there is no doubt that the remaining space is enough for astronauts to survive on spacecraft for longer or carry more materials.

"And what about the second way to shorten the time?"

The first way is simple, with the efficiency of a miniaturized and controllable fusion reactor, it is not difficult to speed up the spacecraft.

At this time, Xu Chuan was more curious about another way to shorten the space time.

Chang Huaxiang smiled and said: "The second way has higher requirements for aerospace technology, and there is a little risk. ”

"How?"

"Omit the orbit adjustment of the spacecraft during the manned landing on the moon or the fire, and land directly on the moon in outer space orbit!"

Hearing this, Xu Chuan glanced at Academician Chang Huaxiang in front of him with some surprise, and said with a slight frown: "Omit the orbit adjustment, will this risk be too great?" ”

Although he is not a scholar in the field of astronautics, he is not ignorant of aerospace.

At least in recent times, he has made up a lot of aerospace knowledge.

As mentioned earlier, when the spacecraft goes to the moon, it does not go straight to the moon, but needs to constantly change orbits around the earth and the moon to adjust the orbit.

The main reason for this is the shortcomings and differences in space technology and theory.

Needless to say, in order to improve the efficiency of rockets, almost all chemical rockets at present have adopted the design of multi-pitch rockets.

At the same time, the irregular shape of the aircraft determines that when it is left on the rocket, the protruding parts such as solar panels and antennas must be folded, and the fairing should be set on the outside.

Therefore, when the last rocket is abandoned, the lunar lander needs a certain amount of time to separate, deploy, power up, test, and so on.

Especially in the testing session, you can't wait until the vehicle is near the moon to find that the vehicle is faulty and needs to be repaired, right?

Orbital flight also has reasons to adjust deployment and test whether the spacecraft will work properly.

The theory, on the other hand, is that the basis of the current use in the aerospace field lies in a theory called 'Hohmann transfer orbit'.

This is the knowledge of high school physics, whether it is the college entrance examination or the competition, it is often tested, and it is a way to change the orbit of a spaceship.

Using Hohmann transfer orbit, the spacecraft can greatly modify its orbit with only two engine propulsions during the orbit change, which can save a lot of spacecraft fuel.

After all, in reality, the larger the orbit parameters changed for each orbit change maneuver, the higher the requirements for engine thrust, and at the same time, it also requires longer working time and higher control accuracy, which means that there will be greater risks.

Multiple orbit detours are also an important means to reduce risks and ensure the safety of spacecraft and astronauts.

If astronauts need to take higher risks to reduce the time to land on the moon, Xu Chuan is reluctant to accept it.

While he wants technology to improve, it can't be based on sacrificing astronauts.

Hearing Xu Chuan's concern, Academician Chang Huaxiang nodded approvingly.

He also proposed this method to see what the young scholar in front of him thought.

After all, it was the first time to meet and cooperate, although I had heard a lot of his stories, but I didn't know his heart.

In academia, paranoia is a trait shared by most scholars, and it is a double-edged sword that can help a person to persevere on the path of study and research at normal times.

But if you are too paranoid, you will go crazy.

Sometimes, some researchers are paranoized about technology or scientific research to the point of desperation.

For example, there are some people who are engaged in biological research, and many times they regard life as crazy as nothing.

Chang Huaxiang naturally didn't want the person in front of him to have this kind of thought, although he really wanted to realize the dream of a space shuttle, but he didn't want to use his ability in the wrong place.

After all, with the current status and ability in China, once there is a deviation, it will be a great blow and loss to the development of the domestic academic community.

But now it seems that the idea of the person in front of me is still very good.

Smiling, Chang Huaxiang said: "It is difficult to omit orbit adjustment in the process of landing on the moon or fire, and put it on a traditional lunar exploration ship, after all, the traditional launch vehicle needs to complete the deployment of the spacecraft after reaching high orbit. ”

"But for the Space Shuttle, it's not impossible to save this step, or rather, shorten the time for orbit adjustment."

"The space shuttle has a lot of advantages over traditional spacecraft, and it is enough to omit a large part of the orbit adjustment without deploying additional solar panels, antennas and other equipment."

"And more importantly, after the breakthrough of miniaturized and controllable nuclear fusion technology in your hands, energy is no longer a shackle for it."

"The sheer size means that the shuttle can carry more supplies, and there is enough energy to allow it to make adjustments even after it has gone off orbit."

Speaking of this, Xu Chuan also understood what Academician Chang Huaxiang meant, and he pondered: "Just like an ordinary civil airliner, although the flight route is fixed at the beginning, it does not mean that it has no ability to modify the route, right?" ”

Chang Huaxiang nodded with a smile and said, "Yes!" ”

"Traditional spacecraft do not have such conditions, because they do not follow this route because of their own design ideas, but the space shuttle has, which is its advantage."

"Especially after the energy problem is solved, in the process of space travel, it can communicate and re-lock the target and direction at any time, just like a vehicle in the atmosphere."

After a pause, he continued: "However, I am afraid that this method will require more computing power, especially if the track is adjusted in real time. ”

Xu Chuan smiled: "This is no problem, just build a supercomputing center." ”

Hearing this, the corners of Chang Huaxiang's mouth moved, and he stopped talking.

He wanted to ask, do you know how much a supercomputing center costs? Even if it is a special type, for aerospace, the price may exceed nine figures.

With this money to build a supercomputing center, I am afraid it will be enough to launch double-digit or even triple-digit satellites into the sky.

Even for the cost of a manned landing on the moon, this is not a small amount.

Is it really inhuman?

Xu Chuan didn't think about it so much, the supercomputing center was really a trivial matter for him.

What's more, the supercomputing center is not a disposable, with the development of time and the increase of space missions, the supercomputing center will only become more and more cost-effective.

After thinking for a while, he spoke: "Academician Chang, you are an expert in the aerospace field, if the work related to the space shuttle is handed over to you, how long will it take to complete?" ”

Hearing this question, Chang Huaxiang thought for a moment and said, "Two years, within two years, I can guarantee that the production of at least one space shuttle will be completed." ”

"It's been too long."

Xu Chuan shook his head, in two years, the daylily was cold.

Chang Huaxiang said helplessly: "This is already very short, we have not developed much on the space shuttle route, and the relevant design and ideas need to be adjusted repeatedly." ”

"In addition, there are some technologies on the space shuttle that need to be overcome, such as the outermost layer of thermal insulation tiles, as well as the production and manufacturing of parts and equipment, as well as the assembly of these, which takes time."

Xu Chuan shook his head and said, "Judging from the current situation, if we want to be the first to land on the moon before the return of the United States, we will have less than a year at most, or even only about half a year." ”

(End of chapter)