Vol 6 Chapter 2889: 15km landing tour

The hall of Xinyuehu Aerospace Command and Control Center in Haoyu Science and Technology Park is already brightly lit, and everyone is in their positions, waiting for the important moment. On the big screen in front of the hall, there is a 3D model image of the moon. On the slowly rotating moon, there are circles of green lines around it. The end of the green line shows a strangely shaped aircraft. The lander of the Lunar Cargo 2 spacecraft launched five days ago, these green lines are exactly its previous orbit around the moon.

In front of the lander, there are these circles of red lines, which are the routes the lander is expected to travel. At the end of the red line, there is a flashing dot, which is the final landing point of the Zhesu lander, the aircraft landing site of the Zhihai lunar surface scientific research station.

In fact, many people confuse a concept. In everyone's impression, it seems that the moon does not rotate. Because in our impression, the moon always faces the earth from the front, and the back can never be seen, so we think that the moon does not rotate. Will rotate the same.

In fact, the moon is rotating, but its rotation period is relatively long. Because "because of the effect of "tidal locking", the moon rotates while revolving around the earth, which is 27 days, 7 hours, 43 minutes and 11.47 seconds, so the moon we see on the earth is always its front, never Can't see his back.

Ten hours ago, the lander had successfully separated from the orbiter, and it is now gradually descending to the height of its orbit around the moon, preparing for landing.

Therefore, today's landing process also attracted a lot of attention, and the guest auditorium in the command and control hall was also filled with many reporters and invited guests.

Wu Hao and the others also came to the scene and accompanied several important guests to witness the entire landing process with their own eyes.

In fact, besides some experts and professors, among these guests were some leaders, including Anxi local leaders and provincial leaders, who came to watch the whole launch process.

In any case, this can be regarded as a grand event in the scientific and aerospace fields in Anxi and even the whole province, so the leaders are also very concerned. They have called several times before to ask for details and care about the progress of the entire project.

Now at this most critical moment, they even came in person, which also made Wu Hao and the others very grateful, and felt the support and concern of the leaders for them.

As the overall person in charge of the entire project, Yu Chengwu also aimed to act as the host and commentator, personally helping them and introducing some important guests who came this time.

"Xiao Wu, when will you land?" The big leader sitting next to Wu Hao looked at the big screen and asked Wu Hao with a smile.

Seeing the leader's inquiry, Wu Hao glanced at the time and replied with a smile: "There are about 40 minutes left, our lander is currently flying around the moon, and gradually lowering the orbital altitude, adjusting the orbital angle, and waiting until the entire landing After the controller reaches this predetermined height and position, it can implement the orbit change and descend.

You see, those red lines on the big screen are its next trajectory. We have to wait until it descends to an altitude of about 15 kilometers and reaches the sky above the lunar basin in the southern hemisphere of the moon. It will be the flashing red dot on the screen. position, and then begin the official landing. The entire descent and landing process takes about 14 minutes, which is also the most dangerous 14 minutes from the rocket launch to the final landing process, which is related to the success or failure of the entire mission. "

"Fifteen kilometers, so low?" This altitude is almost the same as the altitude of our civil aviation aircraft on the earth. Another leader said in surprise.

Hearing the leader's words, Wu Hao nodded with a smile: "That's right, the international flights of our current civil aviation airliners are generally around 13,000 to 16,000, and the final orbit may not be as high as the plane."

"So low!"

After Wu Hao's words fell, the leaders next to him all showed surprise expressions. They also did not expect that the altitude of the orbit around the moon would be so low.

Seeing this, Wu Hao explained with a smile: "The volume of the moon is only one-eighth of that of the earth, its radius is one-fourth of that of the earth, and its weight is only one-eighty-one of that of the earth.

So compared to the earth, it is very small overall and its mass is very light, so its own gravity will be very small, only one-sixth of our earth.

If the gravity on our earth is '1', then the gravity on the moon is only '0.17', which is very small.

In this way, we can calculate that the Karman line of our earth, that is, the dividing line between our earth's atmosphere and space, and also the dividing line of gravity is 100 kilometers.

Above this one hundred kilometers, you can float in weightlessness, and below this altitude, you will feel gravity.

Then if this altitude is converted to the moon, 0.17 is 17 kilometers, so it can be concluded that the Karman line on the moon is 17 kilometers.

Of course, this number is not an exact number, but an approximate value, which may be higher or lower. And affected by the absence of an atmosphere on the moon and the speed of flying around the moon, the altitude of this landing orbit is lower.

These are carefully calculated, so there will be no problems. "

In the end, Wu Hao added that it was a reassurance for the leaders and made them feel at ease.

Sure enough, upon hearing Wu Hao's introduction, the leaders couldn't help but nodded, as they had a general understanding of the entire landing process.

"The altitude of 15 kilometers should not be too high, why is it so dangerous." Another leader who accompanied him immediately raised such a question.

The leaders all laughed at this. Indeed, the altitude of 15 kilometers on the earth is also the flight altitude of international flights. UU Reading www.uukanshu.com is still far from space.

It may also be because of our country's excellent achievements and strong strength in the aerospace field, so it seems to the leaders that such a height is not difficult at all.

Wu Hao was also very helpless about this, but who made the other party the leader? He could only explain with a smile: "On our earth, this altitude is really nothing, even many extreme skydivers can go from 10,000 Skydive at an altitude of more than 20,000 kilometers, and then land safely.

But this is the moon, another planet 380,000 kilometers away from us. Things that are very easy on the earth will have various difficulties on the moon.

It seems that the 15 kilometers seems very simple, but we have to reduce the flight speed of the lander from 1.7 kilometers per second to zero in about 14 minutes during the landing process.

That is to say, during the entire descent process, the engine on the lander must constantly work to decelerate the lander. This process is very important.

…

(end of this chapter)