Why did Chang 'e-1 change track?

For Chang 'e-1, "orbit change" means changing the flight orbit. If the satellite is launched directly from the ground to the earth-moon transfer orbit, it will need a rocket with much greater propulsion than the "Long March 3A" and the launch cost will double. In this launch, the satellite was first put into a super-geosynchronous orbit with an orbital period of 16 hours, and waited for the moon to fly over while the satellite was orbiting the earth, and gradually increased its speed through orbit change. "Chang 'e-1" needs to change its orbit many times during its flight, and finally accelerates to the entry speed of the earth-moon transfer orbit, and realizes the goal of flying to the moon through the satellite's own maneuverability. Although it increases the control difficulty, it can make room for timely and accurate adjustment through multiple orbit changes, and on the other hand, it can save fuel costs.

The process of changing the orbit of a satellite during its orbit operation is called orbit change. Because the speed of the rocket could not reach the starting speed at first, it had to be brewed by the surrounding speed. Therefore, before establishing a smooth communication link and sending back all kinds of detection information, it is only influenced by the gravity of the earth (air resistance is ignored in the ideal state, and of course, the influence of air resistance when crossing the atmosphere is considered through various calculations in practice. And the influence of interstellar debris such as dust when it enters the universe), it will move in a circular motion, and when the speed reaches the speed of the second universe, it will begin to break away from the gravity of the earth. Changing the orbit means that the rocket is adjusting its speed, because the radius of the orbit is proportional to the moving speed.

For more information, please refer to the following:

When an object reaches the speed of 1 1.2 km/s, it can get rid of the bondage of the earth's gravity. In the process of getting rid of the earth's bondage, it does not fly away from the earth in a straight line under the action of the earth's gravity, but flies parabolically. After escaping from the gravity of the earth, it orbits the sun under the gravity of the sun. In order to get rid of the bondage of the sun's gravity and fly out of the solar system, the speed of the object must reach16.7 km/s. At that time, it will fly away from the earth in a hyperbolic trajectory, while relative to the sun, it will fly away from the sun in a parabola.

Human space activities, not blindly escape from the earth. In particular, the current application of spacecraft needs to fly around the earth, that is, to make the spacecraft do circular motion. We know that there must always be a force equal to and opposite to the centrifugal force acting on the spacecraft. Here, we can only use the gravity of the earth. Because the gravity of the earth on the object is just the opposite of the centrifugal force of the object doing curvilinear motion. After calculation, on the ground, when the moving speed of an object reaches 7.9 km/s, the centrifugal force it produces is equal to the gravity of the earth. This speed is called hovering speed.

The speed at which the above-mentioned objects move around the earth is called the first cosmic speed; The speed of getting rid of the gravity of the earth and flying away from the earth is called the second cosmic speed; And get rid of the sun's gravity, the speed of flying out of the solar system is called third cosmic velocity. According to the law of universal gravitation, the gravitation between two objects is inversely proportional to the square of their distance. Therefore, the values of the circling velocity (the first cosmic velocity) and the departing velocity (the second cosmic velocity) of an object are different at different distances from the center of the earth.

The first cosmic speed is 7.8 km/s, so it can fly around the orbit, and the second cosmic speed is 1 1.2 km/s, which can rush out of the earth and third cosmic velocity 16.7 km/s, so it can fly out of the solar system. The orbit of the satellite is elliptical, so the way to save rocket fuel can be to launch it into a large elliptical orbit first. When the satellite is at apogee, adjust the attitude above the satellite to ignite the rocket, so that the orbit of the satellite becomes the required height. Orbit change can be repeated, and it is necessary to accurately calculate the satellite orbit change time, which is controlled by ground instructions.

The process of changing the orbit of a satellite during its orbit operation is called orbit change. The orbit of the satellite is elliptical, so the way to save rocket fuel can be to launch it into a large elliptical orbit first. When the satellite is at apogee, the attitude adjustment fire on the satellite "changes orbit", which means changing the flight orbit for Chang 'e-1. If the satellite is launched directly from the ground to the earth-moon transfer orbit, it will need a rocket with much greater propulsion than the "Long March 3A" and the launch cost will double. In this launch, the satellite was first put into a super-geosynchronous orbit with an orbital period of 16 hours. While the satellite was orbiting the earth, it waited for the moon to fly by, and gradually increased its speed through orbit change. "Chang 'e-1" needs to change its orbit many times during its flight, and finally accelerates to the entry speed of the earth-moon transfer orbit, and realizes the goal of flying to the moon through the satellite's own maneuverability. Although it increases the control difficulty, it can make room for timely and accurate adjustment through multiple orbit changes, and on the other hand, it can save fuel costs.

The process of changing the orbit of a satellite during its orbit operation is called orbit change. The orbit of the satellite is elliptical, so the way to save rocket fuel can be to launch it into a large elliptical orbit first. When the satellite is at apogee, adjust the attitude above the satellite to ignite the rocket, so that the orbit of the satellite becomes the required height. Orbit change can be repeated, and it is necessary to accurately calculate the satellite orbit change time, which is controlled by ground instructions.

The process of changing the orbit of a satellite during its orbit operation is called orbit change. The orbit of the satellite is elliptical, so the way to save rocket fuel can be launched to the large elliptical orbit first. When the satellite is at apogee, the ignition details of the attitude adjustment rocket on the satellite are as follows:

When an object reaches the speed of 1 1.2 km/s, it can get rid of the bondage of the earth's gravity. In the process of getting rid of the earth's bondage, it does not fly away from the earth in a straight line under the action of the earth's gravity, but flies parabolically. After escaping from the gravity of the earth, it orbits the sun under the gravity of the sun. In order to get rid of the bondage of the sun's gravity and fly out of the solar system, the speed of the object must reach16.7 km/s. At that time, it will fly away from the earth in a hyperbolic trajectory, while relative to the sun, it will fly away from the sun in a parabola.

Human space activities, not blindly escape from the earth. In particular, the current application of spacecraft needs to fly around the earth, that is, to make the spacecraft do circular motion. We know that there must always be a force equal to and opposite to the centrifugal force acting on the spacecraft. Here, we can only use the gravity of the earth. Because the gravity of the earth on the object is just the opposite of the centrifugal force of the object doing curvilinear motion. After calculation, on the ground, when the moving speed of an object reaches 7.9 km/s, the centrifugal force it produces is equal to the gravity of the earth. This speed is called hovering speed.

The speed at which the above-mentioned objects move around the earth is called the first cosmic speed; The speed of getting rid of the gravity of the earth and flying away from the earth is called the second cosmic speed; And get rid of the sun's gravity, the speed of flying out of the solar system is called third cosmic velocity. According to the law of universal gravitation, the gravitation between two objects is inversely proportional to the square of their distance. Therefore, the values of the circling velocity (the first cosmic velocity) and the departing velocity (the second cosmic velocity) of an object are different at different distances from the center of the earth.

The first cosmic speed is 7.8 km/s, so it can fly around the orbit, and the second cosmic speed is 1 1.2 km/s, which can rush out of the earth and third cosmic velocity 16.7 km/s, so it can fly out of the solar system.

Instead of using centrifugal force to accelerate. It's just that the speed is not enough, so I can only turn around a few times before I go. I chose a more fuel-efficient road.

There is no resistance in space, only gravity is considered. So it's a long journey, just a little time, not fuel. This is different from walking on the ground.

This accelerates by gravity, saves fuel and increases loading space.

If manned, it will not circle, but it will consume fuel, so the orbit of the satellite will become the required height. Orbit change can be repeated, and it is necessary to accurately calculate the satellite orbit change time, which is controlled by ground instructions. The arrow is lit, so that the orbit of the satellite becomes the required height. Orbit change can be repeated, and it is necessary to accurately calculate the satellite orbit change time, which is controlled by ground instructions. After the launch of Chang 'e-1, it was mainly attracted by the earth, in addition to other stars in space. When the gravity of the earth is the same as the centripetal force required for the satellite to move, the force reaches a balance and the satellite moves around an elliptical orbit. When the satellite accelerates, the centripetal force required by the satellite is greater than the gravity of the earth, and the orbit diameter of the satellite becomes larger, just like a stone tied to a rope and then rotates. When the speed of the stone is high, if there is not enough force to pull it, it will move outward, that is, change its track.

2) According to the statement in 1), when the orbit is enlarged to the earth-moon transfer orbit, both orbits may run, so as long as they are properly controlled, they will run around the moon.

3) As stated in 1), no, they will be in an equilibrium state. It's like you improperly provided a force to make the stone turn, and this force was provided by the moon. 37 years! China has made a great leap from an Earth satellite to a lunar satellite. 165438+1At 8: 34 on October 7, with the Chang 'e-1 satellite officially entering the working orbit 200 kilometers away from the moon, China firmly grasped the fifth admission ticket for the "Moon Meeting". "At the juncture of human activities expanding into space again, China did not delay too many years and efforts as it did in the previous two expansion into the ocean and sky, and finally entered the' Moon Club'." Luan Enjie, commander-in-chief of the lunar exploration project, said.

"At this point, the implementation phase of the Chang 'e-1 launch was successfully completed. "Li Guoping, spokesman of the National Space Administration, said at the fourth press conference of Chang 'e-1 yesterday that this marked the basic realization of the goal of the lunar exploration project, and China had the ability to explore the moon. According to reports, the next step of Chang 'e-1 will be to correct the track deviation and conduct equipment testing in orbit.

165438+ Return the first voice data in October.

It is expected that the Chang 'e-1 satellite 165438+ will send back the first batch of voice data in the end of 10, and all detection instruments will be turned on for scientific detection. Subsequently, according to the requirements of the four scientific objectives, China's ground application system will analyze and process the detection data returned by the satellite to produce the first moon picture.

"According to the working orbit of the satellite and the rotation period of the moon, the CCD stereo camera can cover the entire surface of the moon once a month, the microwave detector can cover it twice, and the interference imaging spectrometer needs to cover it once every two months." Li Guoping said, "By mid-June 5438 +2008 10, all lunar exploration instruments on the satellite will cover the whole moon once."

Solar eclipse threatens satellite communication.

"After the satellite enters the working orbit, it is necessary to establish a three-body directional working posture in order to carry out various lunar exploration activities." Li Tieshou, chief designer consultant of the lunar exploration satellite system, said.

Li Tieshou said that the so-called three-body orientation means that the solar panel of the satellite keeps facing the sun to obtain enough energy; The satellite payload working face keeps the orientation towards the moon to ensure the exploration of the moon; The directional antenna used for data transmission keeps it facing the ground, so that a smooth communication link can be established and various detection information can be sent back. According to the current situation, we are expected to get the first batch of lunar surface image data later this month. Sun Huixian, deputy chief designer of the lunar exploration satellite system, said that the stereo camera carried by Chang 'e-1 satellite used one camera to complete the work that usually takes two or three cameras. It can obtain three two-dimensional images from three different perspectives at the same time, and a three-dimensional map of the lunar surface can be obtained by inversion.

Will Chang 'e-1 capture the footprints of American lunar explorers? Sun Huixian made it clear that the resolution of this footprint pixel should be in the order of centimeters. At present, the cameras on Chang 'e-1 satellite, including those used for international lunar exploration in the past and some other recent lunar exploration projects, do not have such high resolution. To be sure, it is not yet possible to see the footprints clearly through the lunar exploration instrument.

Uncertain development of space station.

In response to a reporter's question about establishing China's first space station, Li Guoping said that according to the Outline of the National Medium-and Long-Term Scientific and Technological Development Plan and the Outline of the Eleventh Five-Year Plan for Space Development, China will continue to carry out research on manned space flight and lunar exploration in the near future. Judging from the various national plans, China has not explicitly proposed to develop the space station.

"At present, the International Space Station established by 16 countries * * * provides convenient conditions for conducting various space experiments in space. Scientists in China are very willing to participate in the experimental work of the International Space Station. " Li Guoping said.

Chang ' e one

10/24 was successfully launched, flying for 326 hours. In recent months, four accelerations, 1 midway orbit correction and three braking were carried out, with a total flight distance of about 1.8 million kilometers, and finally it successfully entered the orbit around the moon, with an orbit period of 127 minutes. Will Chang 'e-1 capture the footprints of American lunar explorers? Sun Huixian made it clear that the resolution of this footprint pixel should be in the order of centimeters. At present, the cameras on Chang 'e-1 satellite, including those used for international lunar exploration in the past and some other recent lunar exploration projects, do not have such high resolution. To be sure, it is not yet possible to see the footprints clearly through the lunar exploration instrument.

Uncertain development of space station.

In response to a reporter's question about establishing China's first space station, Li Guoping said that according to the Outline of the National Medium-and Long-Term Scientific and Technological Development Plan and the Outline of the Eleventh Five-Year Plan for Space Development, China will continue to carry out research on manned space flight and lunar exploration in the near future. Judging from the various national plans, China has not explicitly proposed to develop the space station.

"At present, the International Space Station established by 16 countries * * * provides convenient conditions for conducting various space experiments in space. Scientists in China are very willing to participate in the experimental work of the International Space Station. " Li Guoping said.

Chang ' e one

10/24 was successfully launched, flying for 326 hours. In recent months, four accelerations, 1 midway orbit correction and three braking were carried out, with a total flight distance of about 1.8 million kilometers, and finally it successfully entered the orbit around the moon, with an orbit period of 127 minutes.

Chang 'e-1 time

165438+1in late October, voice data was sent back for the first time, and all detection instruments were turned on for scientific detection.

By mid-June 5438+October 2008 10, all lunar probes on the satellite will cover the whole moon once.