Why did it take 53 days for Chang'e-6 to land on the moon? And the American Apollo spacecraft only takes 8 days?

After digging deeper into the available information, we can't help but wonder why Chang'e-6 took 53 days to explore and return to Earth from the moon, compared to the Apollo mission of the United States that could complete it in just eight days. The difference stems from a complex set of factors and considerations.

First, let's review Chang'e-6's journey to the moon. At noon on May 8, at 10:12 a.m., after five days of rapid space flight, Chang'e-6 successfully withstood the test of solar flare radiation and arrived at the moon steadily. To ensure safe and precise access to the moon's orbit, it performed a critical deceleration maneuver achieved by 3,000 Newtons of thrust generated by the engine's ignition, which lasted 895 seconds, reducing its velocity relative to the moon to 340 meters per second. This deceleration ensured that Chang'e-6 was firmly captured by the moon's gravity and entered a large elliptical orbit that circled the moon for 12 hours.

Next, two flights are planned in this large elliptical orbit, during which Pakistan's local satellites will also be released. Chang'e-6 will then need two more delicate deceleration maneuvers, and is expected to steadily enter a circular orbit 200 kilometers above the lunar surface on May 10. This circular orbit will be crucial for Chang'e-6, like our daily commute from home to work, and it will be a desk for lunar exploration and scientific research.

Although Chang'e-6 took only 10 days from its departure to enter this crucial circular orbit, the rigor of lunar exploration requires that it wait until June 2 to carry out the landing. After landing, it will have a series of delicate tasks to perform, including completing sample collection on June 6. The complexity of the entire mission and the extremely high requirements for precision make Chang'e-6's journey to the moon much longer than that of the Apollo manned mission to the moon.

From public reports, what are the key missions that the mainland's Chang'e-6 has carried out on the moon during the period from May 10 to June 2? Imagine that in our daily work, although 9 a.m. is set as the starting time, it is often not until around 11:30 a.m. that we are really in a productive state of work. However, for Chang'e-6, every moment on the moon is crucial, and there is no room for any idle time.

In fact, Chang'e-6's journey to the moon was so tightly scheduled that it was immediately engaged in a series of crucial missions upon its arrival on the moon. First of all, in order to ensure that the core of the mission, the collection of soil samples on the far side of the moon, could proceed smoothly, it had to conduct a comprehensive test of the communication system. What makes this test so critical is that Chang'e-6's communication with Earth is entirely dependent on the relay service provided by the Queqiao-2 satellite. This is the first time that Queqiao-2 has participated in such a lunar exploration mission, so the mutual adaptation and adjustment between it and Chang'e-6 is particularly crucial.

During this test, Chang'e-6 needed to ensure that the communication link with Queqiao-2 was stable and reliable, just as we had to repeatedly test the network speed, game smoothness, and video clarity after installing a broadband network in our home. The purpose of this is to ensure that all functions run smoothly and provide a solid foundation for subsequent sampling tasks.

In addition to the testing of the communication system, Chang'e-6 also needs to carry out a number of other key tasks, including the survey of the lunar surface, the selection of sampling points, and the commissioning of samplers. Every task is crucial, and none can be left to be sloppy. Only through these rigorous tests and preparations can we ensure that Chang'e-6 will be able to land on the moon and complete its sampling mission on the far side of the moon.

The antenna design of the Queqiao-2 satellite is impressive, with a diameter of 4.2 meters, providing an impressive network transmission speed of 1 gigabit per second for communications on the far side of the Moon. And because the satellite does not reside at the ideal Lagrange L, it chooses a near-straight transfer orbit, which causes it to orbit the moon in about 24 hours. During this long orbital cycle, there is up to 20 hours to ensure stable communication between Earth and Chang'e-6, but unfortunately there is still a 4-hour communication outage.

In contrast, the Queqiao-1 satellite is located at the Lagrange point, which allows it to provide all-weather uninterrupted communication services without any interruption of communication. But this location is unusually far from the surface of the moon, reaching a staggering 80,000 kilometers, so its network transmission speed is relatively slow. The science behind this is well known: as the distance increases, the strength of the wireless network signal decreases, which is why the Queqiao 1 network speed is slow.

However, Chang'e-6's mission is to collect lunar samples, a complex mission that requires extremely high communication speeds. In order to meet this demand, Queqiao-2 chose an orbit closer to the moon, with an altitude of only more than 10,000 kilometers, which greatly improved the signal strength and ensured extremely fast communication speeds most of the time. Despite this, there will still be a 4-hour communication interruption during the night, but considering that most people are asleep during this time, this brief interruption will not cause substantial distress to most people.

In short, Queqiao One is like a broadband network in your home, providing 24-hour uninterrupted service, but the speed is slightly sluggish; Queqiao 2, on the other hand, is a high-speed communications network, with brief interruptions during the night, but fast enough for most of the rest of the day.

According to relevant reports, in view of the abundant fuel reserves of the Chang'e-6 rocket at this stage, the space probe is still capable of further carrying out auxiliary scientific research tasks for several years after the successful completion of the lunar soil collection mission. It is worth noting that since its launch in 2013, Chang'e-3, which has been in operation for nearly ten years, is still in good working condition; Chang'e-5, which has recently completed new experimental missions such as payload transfer and soft landing, is also starting follow-up research work at full speed. Due to the heavy scientific research tasks, after the successful completion of the lunar soil collection mission on June 6, Chang'e-6 will not immediately start the return process, but will continue to work in lunar orbit for half a month, until June 20 before officially departing to return to Earth, and is expected to achieve a safe landing on June 25.