Keywords: remote sensing, international affairs, natural resources of a state, states’ security, disarmament, states’ cooperation
Remote sensing is an applied science, depending on the technological development stage at a certain point in time.
The remote sensing notion comprises, in the specialized doctrine, the same fundamental, but sensibly interpreted elements, taking into account that remote sensing method involves notions of high-resolution technology.
However, all definitions have the same point of reference, i.e. the definition included in the UN General Assembly Resolution no. 41/65 of 3 December. Principle 1 under the Annex sets for that “Remote sensing” means the sensing of the Earth’s surface from the space, by making use of the properties of electromagnetic waves emitted, reflected or diffracted by the sensed objects, for the purpose of improving natural resources management, land use and the protection of the environment.”
In the Romanian doctrine, remote sensing is defined as a method used to determine the nature and condition of Earth natural resources, by observation and measurements made from space objects, or the ”space activity by which information on geophysical phenomena, human activities, natural resources on the Earth surface or underground area both on the territory under States’ sovereignty and in the areas not falling under their sovereignty are collected and stored.
Teledetecţia (Romanian word for remote sensing) is an adaptation of “remote sensing” Anglo-Saxon expression, used ever since the sixties in order to define the technique for information acquisition, a terminology established when the first Earth observation satellites were placed into the orbit.
Today, the same concept has more literal translations, but the teledetecţie or teleobservare (Romanian word for remote observation) terms are the closest to the word etymology.
The development of space technology permitted a variant of the remote sensing concept, applied, at first, to aerial photography (main sensor existing during that period) i.e. satellite remote sensing. Thus, from a strictly technical point of view, remote sensing means “the whole set of techniques, systems and procedures permitting the acquisition and analysis of images at the Earth surface, by means of sensors located at a very high distance”. In this context, remote sensing is the science dealing with the acquisition of information, starting from multi-spectrum photographs, or from the radar, captured by remote sensors (satellites) of items located at a certain distance.
The remote sensing term indicates the acquisition of information about an object situated at a distance, with no material contact between the observed object and the observing object.
In this case, the observed object is the Earth’s land surface, oceans or atmosphere, and the observing object is a sensor located in the air or in the outer space, capable to detect and store information which is to be analyzed later.
In fact, remote sensing includes any method of obtaining and recording information from a distance.
Remote sensing includes not only the processes and instruments permitting the capturing of an image of the Earth surface from a distance, but also the processing required for certain determinations.
For this point of view, remote sensing activities also include the procedures subsequent to the acquisition of information by satellite, as listed in the UN General Assembly Resolution no. 41/65/1986. It results from the provisions of the UN document that the “remote sensing” term has two limitations as regards the technical term: the purposes and objectives of a military use are limited and remote sensing from the air is excluded.
Therefore, whatever the name of this technology would be, the essence of the definitions delineating the “remote sensing” or ”remote observation” terms is that of observing an item from a high distance via high-technology methods.
The remote sensing field is subject to rapid transformation, through the impact caused by new platforms, sensors, space information handling and analysis methods.
The evolution of the Earth observation technology via satellites gives no accurate data on the time when such high resolution technique was applied, because the satellites that used this system were of military application.
Photographs of the Earth were initially taken from the air, i.e. at the end of the First World War, over one million photographs dating from that period, but the actual techniques of recognition through the remote sensing method were used during the Second World War No important military movement could be initiated without having captured and interpreted the aerial photographs of the area. During this period there was an interest in civil use techniques for prospecting minerals and oil in the Earth’s underground areas.
The origins of aerial photographs of the Earth surface are unknown. The first aerial photographs were taken in France, in 1839, and the first topographic maps were made in 1840, being provided by the manager of the Paris Observatory. In 1858, Gaspard Felix Tournachon flied above Paris in a balloon intending to draft the city map.
The forerunners of remote sensing were the military reconnaissance balloons, used during the North American civil war and the war of the Triple Alliance.
In 1906, G. Lawrence developed, in the USA, a mechanism permitting the transport of cameras by which he took aerial photographs of the damages caused by the San Francisco earthquake. The first aerial photographs were obtained by Wilbur Wright in 1909, in Italy.
We can speak about actual remote sensing, as defined today, after the launch of Sputnik Soviet satellite, when the United States of America placed in the orbit the first Earth observation satellite equipped with an optical sensor, the satellite being manufactured for military purposes.
The official beginning of remote sensing systems, open to scientific community, is year 1972, when LANDSAT 1 satellite was launched, being followed by LANDSAT 2, in 1975, and LANDSAT3, in l978.
Also in 1978, the US launch another satellite, named SEASAT, whose lifetime in orbit is only 100 days. It seems that its scheduled and intended destruction was caused by the high amount of information it provided to various persons or institutions, which rendered any control impossible.
As regards the remote sensing activity of the former USSR, it places remote sensing satellites in orbit during the period 1980 and 1998 under the name of SPIN, but the information regarding such satellites is classified.
Western Europe launches out in the field of remote sensing satellites with SPOT 1, made in France, placed in orbit in 1986. Two years later, US manufacture Lacrosse platform, the first spy radar system, and ESA launches in 1991 ERS 1 satellite, followed by ERS 2, launched in 1994, a satellite that is operational even today.
The nineties, when the world political arena was marked by the destruction of the communist system in Eastern European countries, was a point of reference as regards the launches of satellites for remote sensing purposes also by other States in possession of space technology.
The use of artificial satellites in remote sensing gives this technology a practical applicability that is extremely important and beneficial, consisting in meteorological and seismic forecasting, evolution of crops, fire detection in forests, information about ice sheets, detection of underground ores and biological resources.
Today, the outer space is no longer dominated by a few States. Almost 150 countries, several from the so-called ”Third World" are directly or indirectly involved in space activities used for national development, remote sensing showing its usefulness for poorly developed countries, which gave the name of the ”Third Big Space Race".
The specialized and universally oriented works and documents issued by worldwide organizations frequently focused on the importance and benefits of space and remote sensing activities. In order to carry out and correlate the objectives and purposes of such organizations, space activities are becoming indispensable today. We are particularly referring to satellite telecommunications and remote sensing, without which the exchange of information between intelligence organizations could not be carried out in an optimal manner.
Due to the fast scientific development, remote sensing was not regulated in detail so as to avoid disagreements within international organizations, the subject of such discussions being mainly the dissemination of the acquired information.
At the same time, the privatization and sale of space activities, including remote sensing activities, increase the role of developing States...