Americans have already landed on the moon and have already "spent". Apollo plans to return to the moon with 6 manned landings. Armstrong only fired the first shot. Their current target is Mars . The "rocket" that Apollo planned to return did not land on the moon, but hovered in orbit around the moon. This process was like you took a taxi from home and arrived at the edge of the pond. You told the driver: You circle the pond for a few times, I went down to touch a fish, and then came up to meet you, and then went home.
Apollo plan to pave the way for the moon landing
First of all, Chang'e-5 is about to land on the moon, and we also want to bring back some lunar "special products" to the moon, indicating that the plan to return to the moon is feasible. The Apollo plan is not the only Apollo No. 11 that Armstrong rides. No. 11 indicates that there are 1 to 10 in front of it.
Picture: Apollo-1 wreckage
Apollo plan was not smooth. The Apollo-1 , which was originally planned to be launched on February 21, 1967, was announced to be over before it was launched. A month before the launch, a routine test, the command module caught fire, and all three astronauts died in just 15 seconds.
The Americans followed by Apollo 2-6 were honest, but they tested Saturn 5 and the various cabins of the spacecraft without carrying people, including orbital ignition, moon return simulation, etc.
Americans were not in a hurry to land on the moon. Later, Apollo 7-10 carried manned orbiting the earth, around the moon, and back and forth, including lunar module and the command module for manned docking in space. These missions were successful, and they were not far from the manned moon landing. The only part of the entire manned moon landing plan that has not been tested is: lunar module lands on the moon, and samples are collected and taken back.
Apollo 11 After humans "take a big step", the Apollo plan continued until the 17th, with 6 successful moon landings. Many people ask, if the United States had succeeded in the first place, why wouldn’t it land on the moon now? Here is the answer, because they have successfully landed the moon six times, and the cost of each landing is huge, and it will be no new if you go too much. It is better to use it on Mars than to have strength.
Moon is a stepping stone for humans, or an experimental base, because it is currently the only planet that humans can experience in the vast universe. We want to take people to a farther place, and the only thing we can test is the moon.
If you understand the history of the Apollo Project, you will know that Americans are actually not as powerful as you think, they are just ahead of us. Chang'e is currently on the 5th. When Chang'e moves to the 11th, it is estimated that the Chinese have already landed on the moon. Then we solve the last question, how Armstrong came back with the "stone".
How to return astronauts
Moon is the Earth's satellite . In the universe, the size of mass determines the size of gravity, so the Earth is the one that dominates the gravity in the Earth-Moon system . When we go to the moon, we are overcoming the gravity of the earth, and when we return, we are "hurrying", but this is not the key.
Based on gravity, the larger the planet and the more compact it is, the harder it is to get out of it, because the greater the force, the greater the reverse acceleration when we want to leave, and the greater the initial speed we need to fly out of the planet.
The mass of the moon is only 1.2% of the earth, but it is like a cake with a radius of 27% of the earth, so it is easier to escape than the earth. In order to get rid of the gravity of the earth, we need to leave the earth's surface at a speed of 11.2km/s. If you want to escape from the moon, you only need to reach 2.4km/s.
The Saturn V rocket used when Apollo 11 went is still ranked second in the world. So how big does the rockets returning from the moon need?
Two things need to be clear here:
Apollo 11 lunar module has not come back. It is only responsible for landing on the moon and taking off from the moon. The relationship between velocity and energy is square.
When the spacecraft reached the lunar orbit, Saturn V's thruster had long disappeared, leaving only the command module, service module, and lunar module (upgrade, downgrade). Three astronauts and two entered the lunar module to land, one stayed in the command module and orbited the moon, waiting for the lunar module (upgrade) to send back the two astronauts and the collected samples. The shuttle bus that finally returned home was the command module.
From this we can see that the Americans have strict control over the quality of the lunar module, and minimize the quality of landing as much as possible because the larger the mass, the greater the energy required for takeoff. Secondly, the mass and the energy required for the moon to take off mean that the fuel, energy (kinetic energy) is the square of the velocity. In other words, the velocity of the moon (2.4) and the velocity of the earth (11.2) are about 1:5, which means that if you need to escape from the earth, you actually need 25 times the energy, that is, 25 times the fuel.
However, it is not just that:
Apollo does not need to escape from the moon, it only needs to enter the orbit of the moon to connect with the command module, so it only needs to reach the first cosmic speed of the moon 1.8km/s. The total weight of Saturn V when departs includes the fuel for the outbound and return journeys, and the load is larger. When taking off from the moon, it only needs to fly into the moon orbit, so there is not such a large load when descending, and the proportion of size is further increased. When the Apollo landed, it was landed with the upper upgrade and the downward stage. When it was about to take off, the downward stage remained on the moon as a launcher, and only the upper upgrade and the downward stage was lifted off, which further increased the proportion.
In summary, the rocket that takes off from the moon only needs the lunar module itself and does not require additional rocket boost. The matter of returning to the earth is handed over to the service compartment with sufficient fuel. Finally, the service compartment breaks away from the command compartment, and the command compartment enters the atmosphere and falls into the sea.
Figure: Separation of command cabin and service cabin
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