Dongfanghong-1, as the first artificial satellite in China, uses silver-zinc battery as energy source, with an expected working life of 20 days and an actual working life of 28 days. During its on-orbit work, it measured the basic data of outer space and used special geometric modeling. A skirt? Structure, is it realized? Show it to people on earth? Reflected sunlight level.
Today, 50 years later, although the power of Dongfanghong-1 has been out for a long time, it still maintains its original orbital height and revolves around the earth day after day. So what makes a173kg iron block without energy orbit the earth in space for 50 years?
The answer to this question should start with Newton.
1687, after Newton's Mathematical Principles of Natural Philosophy was published, people knew that as long as the speed of an object reached 7.9km/s, it could fly out of the atmosphere, make a circular motion around the earth without falling into the earth, and become like the moon.
But unlike most people's imagination, space is not a vacuum in the strict sense, especially in the near-earth space below 400 kilometers, which Newton could not achieve? Like the moon? Dreaming.
Because atmospheric molecules in the outermost layer of the earth's atmosphere are blown by the solar wind all the time? Strip? Stripped atmospheric molecules wander in low earth orbit for a long time, causing space stations and satellites to operate below 400 kilometers. After a long time, the speed will be reduced because of these air molecules, and the consequence of reducing the speed is the decline of the orbit. Therefore, the international space station in orbit will use extra power to upgrade its orbit every few years to avoid falling into the earth because of its slow orbital speed.
The secret of Dongfanghong-1 staying in orbit for a long time without falling into the earth lies in its orbital height.
Because Dongfanghong-1' s orbit around the earth is elliptical, there is bound to be a difference between perigee and apogee, just as the earth has perigee and apogee, and the perigee orbit height of Dongfanghong-1 is 440km. In this high space, there are almost no atmospheric molecules on the earth, that is to say, in a high sense? Vacuum? The three laws of mechanics will be restored to the greatest extent here.
According to Newton's first law, an object will remain stationary or move in a straight line at a constant speed before being acted by an external force.
And Dongfanghong No.1 is in No.1 Middle School? Almost no external force? Space, so it perfectly inherits the original orbital speed, and can continue to maintain its elliptical orbit for 50 years under the action of the earth's gravity.
In the foreseeable future, Dongfanghong-1 will still be in orbit. If the future of Dongfanghong-1 is never destroyed? Second arrest? Otherwise, 500 or even 5000 years later, it will still rotate in the high orbit of the earth.