Main source: Beijing News "Chang'e-6 set off to "go to the moon", how difficult is it to "dig" on the far side of the moon? 》2025.5.3
Preface
The mainland folded Chang'e-6 on May 3, and successfully performed emergency braking on May 8 to enter the orbit around the moon, which is currently orbiting the moon.
And the United States' Apollo 11 60 years ago only needed 4 days to successfully land on the moon.
Could it be that China's technology in 2024 is not as good as that of the United States 55 years ago?
Chang'e VI
On May 3 this year, the Long March 5 Yao-8 carrier rocket carrying the Chang'e-6 probe was ignited and launched at the China Space Launch Site.
The Chang'e-6 probe weighs 8.2 tons, which is also the most complex and heaviest lunar probe ever made, and it travels to the moon 380,000 kilometers away.
Therefore, the mainland also used the strongest Long March 5 carrier rocket in service this time, so as to ensure that Chang'e-6 can be successfully lifted off and complete the mission.
The reason why Chang'e-6 is heavy this time is because the mission is complex and requires more equipment, and international cooperation has been carried out, carrying a number of national scientific payloads.
Among them, the international payloads carried include the ESA Lunar Surface Negative Ion Analyzer, the French Radon Detector, the Italian Laser Corner Reflector, and the Pakistani CubeSat.
Chang'e-6 is composed of four parts: orbiter, returner, lander and ascent, which will support Chang'e-6's return to Earth after completing its mission.
As the sixth probe of the mainland Chang'e lunar exploration project, Chang'e-6 is also a key node of the mainland lunar exploration project, and the task of Chang'e-6 is also very arduous.
The whole process will take 53 days, the first step is for the probe to be launched into space by the launch vehicle, and the second step is for the Chang'e-6 probe assembly to be separated from the launch vehicle.
After the separation operation, the third step, Chang'e-6 enters the Earth-Moon transfer orbit, and officially begins to march towards the Moon after entering the Earth-Moon transfer orbit, and the orbit altitude is about 200 kilometers at the perilunar point, and one to three orbit corrections are required.
After that, the probe needs to perform a near-moon braking near the perilunar point, which is what we call "braking", at which time the Chang'e-6 probe flies at an altitude of about 200 kilometers at the perilunar point.
Since it has entered the orbit around the moon, it is necessary to choose the time to release the CubeSat of Pakistan and carry out a sub-operation, so that the CubeSat of Pakistan can enter the orbit around the moon alone.
After two brakings, it will enter an orbit around the moon with an average altitude of 200 kilometers and a circumlunar period of only 2 hours, and the fourth and most critical step is to separate the Chang'e-6 ascent assembly and the orbital returner assembly, and after separation, the orbital return assembly is waiting in the lunar orbit.
Then the landing ascent group will fly around the moon, enter an orbit closer to the moon by performing two orbit lowering operations, and choose the opportunity to land.
Then, after completing the mission, the ascent vehicle complex and the orbit return assembly docked and returned to Earth.
Therefore, it can be seen from the mission process of Chang'e-6 that the mission to the moon is very complex and requires a large number of operations, and Chang'e-6 has successfully entered the orbit around the moon on May 8, and has now flown in the orbit around the moon, and has not yet carried out the landing operation.
Therefore, Chang'e-6 has not landed on the moon for nearly 9 days, why did Apollo 11 land on the moon 4 days ago 55 years ago?
Reference: North Evening Online "Aim at the back of the moon! From running to the moon to going home, Chang'e-6 has to take 11 steps" 2024.5.3
North Evening Online "Aim at the back of the moon! From running to the moon to going home, Chang'e-6 has to take 11 steps" 2024.5.3
Apollo 11
Apollo 11 was a program of the National Space Administration (NASA) in May 1961, during the Cold War between the United States and the Soviet Union, the space race was fierce, and both the Soviet Union and the United States could not wait to achieve the moon landing program as soon as possible.
So on July 16, 1969, after four manned missions, the United States chose to land on the moon, thus dealing a fatal blow to the Soviet Union, in order to declare its achievements in the field of space.
At 9:32 local time in the United States, the Kennedy Space Launch Center at the Apollo 11 launch site has attracted more than one million people to watch the scene, and the live broadcast record of the Apollo launch site around the world has reached 600 million, setting a world record.
With the successful ignition of the Saturn V launch vehicle carrying Apollo 11, the largest launch vehicle of mankind was successfully launched, and after 12 minutes of flight, the spacecraft successfully entered the Earth's orbit.
After a one-and-a-half-orbit around the Earth, the third stage of the Apollo 11 rocket ignited, accelerating the spacecraft to 10.5 kilometers per second and heading for Earth-Moon transfer orbit.
After 30 minutes, the command module/service module separated from the Saturn V and after a 180-degree rotation it connected to the lunar module in the third stage of the rocket and headed for the moon.
In about three days, Apollo 11 was near the moon and decelerated the Apollo 11 manned spacecraft by igniting the main rocket to enter lunar orbit.
After that, it was necessary to identify the expected landing site of the moon, and in the process of orbiting the moon, three astronauts identified the planned "landing site" in the air.
So, in less than a day, the Apollo 11 spacecraft was going to land, so on July 20, Earth time, Apollo 11 successfully landed in the southern part of the moon's quiet sea, 20 kilometers southwest of the Sabine D crater.
The main reason is that this site is flat compared to other sites on the moon, and because of the choice of this site, because of the voucher, it is very easy for Apollo 11 to land and carry out extravehicular activities.
Therefore, it can be seen that the United States was able to complete the lunar landing in four days with Apollo 11 55 years ago, which makes people marvel at the strength of the American lunar landing technology.
The United States manned moon landing 55 years ago took 102 hours and 45 minutes, about 4 days, and the countries of the world in the 21st century could not land on the moon in 4 days, and the Indian probe needed 21 days to enter the orbit around the moon.
Even with the mainland's current achievements in the lunar exploration program and rich experience, it took Chang'e-6 five days to enter the orbit around the moon.
Why is there such a big gap with the United States?
Reference: Todd Douglas Miller, "Apollo 11 Documentary", July 7, 2019
Todd Douglas Miller, Apollo 11 Documentary, July 7, 2019
Why is the gap so big?
First of all, the rocket used by the United States is the Saturn V, which is the most powerful launch vehicle of mankind at present, with a height of 110.6 meters alone, and a take-off weight of 3038.5 tons and a total thrust of 3048 tons.
And the carrying capacity in lunar orbit has reached 45 tons, and the carrying capacity in low-earth orbit can reach 118 tons, even today in the 21st century, there is no rocket with greater thrust than Saturn V, even the United States itself has not done it.
The mainland's Chang'e-5 uses the "Long March 5 Yao-8 launch vehicle", the carrier rocket with the largest thrust currently used by the mainland, with a total length of nearly 60 meters, a take-off weight of 869 tons, and four thrusters tied.
Therefore, the Long March 5 Yao-8 launch vehicle can carry 25 tons in low earth orbit and 14 tons in geosynchronous orbit, which is the largest rocket in the continent's medium and high space orbit.
Although the carrying capacity of the Long March 5 is already powerful, compared with the data of the Saturn V, there is still a big gap, and there is an obvious gap in thrust and carrying capacity.
Therefore, on the way to the moon, Saturn V can provide Apollo 11 for the United States when it goes to the moon, providing faster rotation and transportation capabilities, so with the help of such a large thrust, Apollo 11 can land in about 4 days.
However, after all, Apollo 11 is a manned landing on the moon, and the mass of the spacecraft itself is very large, of which the overall Apollo 11, including the command module, the lunar module, astronauts and various equipment, has reached 78 tons.
After disengaging from the command module, Apollo 11 also weighed 48 tons and carried 2.5 tons of fuel, so a rocket of Saturn V's thrust was needed to send them to the moon.
Chang'e-6 is an unmanned probe with an overall weight of only 8.2 tons, so the use of a launch vehicle like the Long March 5 is completely sufficient.
So, from this aspect, is it possible to prove that the technology of the United States in 55 years is already more advanced than that of other countries in the 21st century?
The United States' achievements in the field of aerospace are understandable, but after all, unmanned exploration and manned lunar exploration are indeed different, and the United States has never set foot on the moon since the implementation of the Apollo program.
The return to the moon program has also been postponed indefinitely for various reasons, and the United States cannot come up with a launch vehicle of the Saturn V class now, so in terms of lunar exploration engineering technology, it cannot be said that China's technology is worse than that of the United States 55 years ago.
Not only that, the "Odysseus" lunar probe recently launched by the United States also took about five days to enter the orbit around the moon, so it can be said that in terms of lunar exploration technology in the 21 st century, the gap between the level of China and the United States is not large.
Another point is that Chang'e-6 entered the orbit around the moon on the fifth day (May 8) after its launch, why did it refuse to land?
Reference: Beijing News "Chang'e-6 set off to "go to the moon", how difficult is it to "dig" on the far side of the moon? 》2025.5.3
Beijing News "Chang'e-6 Sets Off to "Run to the Moon", How Difficult Is It to "Dig Soil" on the Far Side of the Moon? 》2025.5.3
The moon is the most difficult for humans to explore without man
Because the Chang'e-6 mission has also been called "the most difficult unmanned human exploration of the moon"!
At present, the whole mission process of Chang'e-6 has reached 53 days on this "business trip", and it has to go through 11 flight stages:
"Launch into orbit section, Earth-Moon transfer section, near-moon braking section, circumlunar flight section, landing descent stage, lunar surface working section, lunar surface ascent stage, rendezvous docking and sample transfer section, circumlunar waiting stage, moon-to-ground transfer section and re-entry recovery stage."
Therefore, it can be seen that the complexity of the Chang'e-6 mission seems to be much more complicated than the "Apollo 11 manned lunar mission".
And compared with the manned landing site of Apollo 11 on the moon, the location of Chang'e-6 this time can be said to be "a field that humans cannot set foot in".
Because the far side of the moon that I visited this time is tidally locked between the earth and the moon, the orbital period of the movement of the moon and the earth is exactly the same as the rotation period of the moon itself, so there are a large number of "dark areas" on the far side of the moon, which is also called the "lunar sea".
The far side of the moon is full of meteorite impact craters and radiation and dust from the universe, and it is also a "forbidden area" for space communications, and the landing mission on the far side of the moon is almost impossible until the mainland launches the "Queqiao-2" satellite.
And Chang'e-6 is not only going to the far side of the moon, but also the south pole of the moon-Aitken Basin, also known as the coldest place on the moon.
As the largest meteorite impact crater on the Moon, the Aitken Basin has a diameter of about 2,500 kilometers, a depth of 13 kilometers, and a maximum drop of 16.1 kilometers, which is also the oldest and deepest impact crater, which can be formed 4 billion years ago.
Therefore, Chang'e-6 will go to this area this time, and it will also go deep into the moon 2 meters below the ground to collect soil from the far side of the moon, which is also the first time that humans have collected soil from the far side of the moon.
Therefore, Chang'e-6 is more difficult than any lunar exploration mission in the environment, and there is no relevant experience in landing on the far side of the moon, so the choice of Chang'e-6 landing site needs to be very cautious, because 97.5% of this area is craters and impact craters, so the landing site requirements are strict.
Therefore, when Chang'e-6 enters the circumlunar orbit stage, it will take about 20 days to observe the landing position and adjust the attitude before it can land.
Moreover, at the end of March this year, the American lunar lander "Odysseus" broke a "leg" when landing on the front of the moon due to insufficient preparation for landing.
Therefore, mainland scientists are very cautious about the first landing on the far side of the moon, so Chang'e-6 needs to make all preparations to complete the most difficult unmanned lunar mission of mankind.
Reference: Guangming Network "Intelligent Sampling on the Back of the Moon! Chang'e-6's 53-day space "business trip" is interlocking, and the key step by step is "2024.5.8
Guangming Network "Intelligent Sampling on the Back of the Moon! Chang'e-6's 53-day space "business trip" is interlocking, and the key step by step is "2024.5.8
epilogue
It is undeniable that although the United States has not returned to the moon for so many years, the United States has also made great contributions to human space exploration.
And just by the landing time, there is no way to face the technical gap, after all, the nature of the two missions is completely different, so it is hoped that countries can increase their efforts in the field of exploring the moon and space!
Resources:
Guangming Network "Intelligent Sampling on the Back of the Moon! Chang'e-6's 53-day space "business trip" is interlocking, and the key step by step is "2024.5.8
Beijing News "Chang'e-6 Sets Off to "Run to the Moon", How Difficult Is It to "Dig Soil" on the Far Side of the Moon? 》2025.5.3
Todd Douglas Miller, Apollo 11 Documentary, July 7, 2019
North Evening Online "Aim at the back of the moon! From running to the moon to going home, Chang'e-6 has to take 11 steps" 2024.5.3