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1. It's two forces that bring the object to equilibrium

2. Isn't that right

e = f * r
differential
de = f * Dr
de = GMM * R ^ (- 2) * Dr
the indefinite integral on both sides is
e = - GMM / R + C
taking R →∞ as the reference point
the definite integral is
e = - GMM / R

3.

The power source of the satellite is to use conventional chemical fuel before entering orbit, and then turn on the electric propulsion engine after entering orbit

In this case, the orbit parameters of the satellite need to be adjusted

at the same time, from the perspective of remote sensing, communication and military tasks, it is also necessary to adjust and control the attitude properly when the satellite is in orbit

to adjust and control the orbit and attitude of a satellite, we need corresponding power, which comes from the power system on the satellite, but the power required for adjustment and control is far less than that required for launching the satellite into orbit. This power system on the satellite is called micro propulsion system, which can be divided into physical propulsion system, micro propulsion system and micro propulsion system Chemical and electric propulsion systems

extended data

the orbit of a man-made satellite depends on the mission requirements of the satellite, which is divided into low orbit, medium high orbit, geosynchronous orbit, geostationary orbit, sun synchronous orbit, large elliptical orbit and polar orbit. The speed of man-made satellites around the earth is fast. In low and medium orbits, high orbit satellites can fly around the earth several to more than ten times a day. They are not limited by territory, airspace and geographical conditions, and have a wide field of vision

it can quickly exchange information with the ground, including the transmission of ground information, and also obtain a large amount of remote sensing information of the earth. The area of remote sensing of a satellite image of earth resources can reach tens of thousands of square kilometers. When the orbit altitude of the satellite reaches 35786km and it flies along the same direction of the earth's rotation above the equator, the rotation period of the satellite around the earth is exactly the same as that of the earth's rotation

the relative position of the satellite remains unchanged, and it seems that the satellite is still hanging in the high altitude on the earth, which is called geostationary orbit satellite, or geostationary satellite for short. This kind of satellite can realize the uninterrupted information exchange between the satellite and the ground station, and greatly simplify the equipment of the ground station

the vast majority of TV relay and forward communication through satellite is realized by geostationary communication satellite

artificial satellite is the spacecraft with the largest number of launches, the widest use and the fastest development. According to different orbits, man-made satellites are divided into low orbit satellites, medium and high orbit satellites, various man-made satellites, geostationary satellites, sun synchronous satellites, large elliptical orbit satellites and polar orbit satellites; According to their uses, man-made satellites can be divided into communication satellites, meteorological satellites, reconnaissance satellites, navigation satellites, geodesic satellites, interception satellites, etc