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SATELLITES AS POWER MULTIPLIERS

By Taxiarchos, R.E. P. Leonardos

On 18-3-1965, Alexei Leonov was the first man to walk in space and on 20-7-1969, Neil Armstrong was the first man to walk on the Moon. Since then, continuous space missions and rapid technological development have brought space to the "extension" of the earth. New communication models increasingly rely on space services, while nothing on earth escapes the satellite "eye". Space technology has already brought about significant changes in the way military conflicts are conducted via satellites and, without a doubt, we are facing radical changes in strategy and geopolitics.

Satellite Technical Data

Satellites, based on the needs they serve, can be classified into three major categories. Earth observation satellites, telecommunications satellites and positioning and navigation satellites. The orbits of the satellites and the heights above sea level vary depending on their purpose. Thus, earth observation satellites rotate in low orbits of 150-5.000 km mainly, when they are used for the identification and interception of signals, as well as for meteorological and geodetic purposes, while telecommunications satellites rotate in geosynchronous orbit, that is, at altitudes of 35.000 km, and positioning and navigation satellites in semi-synchronous orbits and altitudes of approximately 20-23.000 km.
Satellites with geosynchronous orbit are called geostationary when they rotate at the height of the Equator with a period of 24 hours, direction and speed with that of the Earth's rotation and thus appear fixed in relation to their observation point on Earth. This fact helps them to cover certain areas without interruption in telecommunications. This is in contrast to observation satellites, which, by performing remote sensing for photography, have a revisit time of a specific point, at best, from one to four days. Of course, this is also their disadvantage at the moment, namely that they are not suitable for exploiting their data in real-time military operations.
The lifespan of a satellite system depends mainly on the orbit and the equipment of the satellite (battery chargers, amount of fuel, etc.). Today, geostationary satellites have a lifespan of 10-15 years, while low-orbit satellites have a lifespan of 5-7 years, and the closer they get to the Earth, the shorter their lifespan becomes, due to the greater damage they face.

Satellite Communications – Overview

A typical satellite communications or remote sensing system consists of two main parts: the space and the ground. In the case of telecommunications satellites, it should be emphasized that they provide guaranteed connections, because they ensure the line of sight required for the retransmission of the radio waves used in telecommunications. The caller is connected to the ground station that serves him. The ground station is "seen" by a satellite to which it sends the signal. This relays to another satellite, which "sees" the ground station that serves the called party and transmits the signal to it. Three geostationary satellites in Equatorial orbit can cover the entire Earth's surface. Unfortunately, our country lacks satellite communications although it recently has a telecommunications satellite, HELLAS-SAT.
In relation to remote sensing, after the satellite visits the point to be photographed, the image is then transmitted to the ground station from where its photointerpretation and distribution take place. In addition to the problem of revisiting that was formulated above, the problem of improving the time of image acquisition must be solved, from a procedural point of view, so that they reach the user in a timely manner. This problem is solved either by a special agreement with the owner of the ground station (owned by a company or another state) for preferential treatment on a commercial basis or, even better, by acquiring a proprietary satellite, and even a mobile one, so that the survivability of the system is achieved in the event of a crisis or war. Our country recently entered the “HELIOS-2” program, which is the only military satellite system in Europe and participates in the consortium in which France has the first say. However, to achieve better results, we will also need to proceed with the procurement of ground stations.
Space satellites can therefore be considered as important force multipliers and the exploitation of space should be sufficient for modern Armed Forces.