What causes the altitude and inclination of the ISS orbit

The choice of some parameters of the orbit of the International Space Station is not always obvious . For example, a station can be located at an altitude of 280 to 460 kilometers, and because of this, it constantly experiences the inhibitory effect of the upper atmosphere of our planet. Every day, the ISS loses approximately 5 cm / s of speed and 100 meters in height. Therefore, it is necessary to periodically raise the station, burning the fuel of ATV and Progress trucks. Why can’t you raise the station higher to avoid these costs?

The range laid down during design and the current real position are dictated by several reasons at once. Every day, astronauts and astronauts receive high doses of radiation , and beyond the 500 km mark, its level rises sharply . And the limit for a six-month stay is set at only half avert, for the whole career only a Sievert is reserved. Each sievert increases the risk of cancer by 5.5 percent.

On Earth, we are protected from cosmic rays by the radiation belt of the magnetosphere of our planet and the atmosphere, but they work weaker in near space. In some parts of the orbit (the South Atlantic anomaly is such a spot of increased radiation) and beyond, strange effects can sometimes manifest: Flashes appear in closed eyes. These cosmic particles pass through the eyeballs, and other interpretations claim that the particles excite parts of the brain that are responsible for vision. This can not only interfere with sleep, but also once again unpleasantly recalls the high level of radiation on the ISS.

In addition, the Unions and Progress, which are now the main crew change and supply ships, are certified to operate at altitudes up to 460 km. The higher the ISS, the less cargo can be delivered. Less will be able to bring rockets that send new modules for the station. On the other hand, the lower the ISS, the more it is slowed down, that is, the more delivered cargo should be fuel for subsequent orbit correction.

Scientific tasks can be performed at an altitude of 400-460 kilometers. Finally, space debris affects the position of the station - failed satellites and their debris, which have tremendous speed relative to the ISS, which makes a collision with them fatal. There are resources on the Web that allow you to monitor the orbit parameters of the International Space Station. You can get relatively accurate current data , or track their dynamics . At the time of this writing, the ISS was at an altitude of approximately 400 kilometers. The ISS can be accelerated by elements located at the rear of the station: these are Progress (most often) and ATV trucks, and if necessary, the Zvezda service module





" (rarely). In the illustration, the European ATV works before the kata. The station is often raised little by little: the correction occurs approximately once a month in small portions of about 900 seconds of engine operation, with Progress, smaller engines are used so as not to greatly affect the course of experiments.

Engines can turn on once, thus increasing flight altitude on the other side of the planet. Such operations are used for small ascents, since the eccentricity of the orbit changes. A correction with two inclusions is also possible, in which the second inclusion smooths the orbit of the station to a circle. Some parameters are dictated not only by scientific data, but also by politics. The spacecraft can be given any orientation, but at launch it is more economical







will use the speed that the rotation of the Earth gives. Thus, it is cheaper to launch the device into orbit with an inclination equal to latitude, and maneuvers will require additional fuel consumption: more to move to the equator, less when moving to the poles. The ISS orbital inclination of 51.6 degrees may seem strange: NASA vehicles launched from Cape Canaveral traditionally have an inclination of about 28 degrees. When the location of the future ISS station was discussed, they decided that it would be more economical to give preference to the Russian side. Also, such orbital parameters allow you to see more of the Earth's surface.





But Baikonur is located at a latitude of approximately 46 degrees, why then is the 51.6 ° inclination common for Russian launches? The fact is that there is a neighbor to the east who will not be too happy if something falls on him. Therefore, the orbit is tilted to 51.6 °, so that at launch no parts of the spacecraft could under any circumstances fall on China and Mongolia.