During geological surveys carried out from aircraft, the emission or reflection of electromagnetic waves by natural objects is recorded. Remote sensing methods are conditionally divided into methods of studying the Earth in the visible and near infrared regions of the spectrum (visual observations, photography, television filming) and methods of the invisible range of the electromagnetic spectrum (infrared survey, radar survey, spectrometric survey, etc.). Let's stop at brief description these methods. Manned space flights have shown that, no matter how perfect the technology is, visual observations cannot be neglected. The observations of Yu. Gagarin can be considered the beginning of them. The most striking impression of the first cosmonaut was the view of his native Earth from space: “Mountain ranges, large rivers, large forests, spots of islands clearly appear ... The Earth pleased with a juicy palette of colors ...”. Cosmonaut P. Popovich reported: "Cities, rivers, mountains, ships and other objects are clearly visible." Thus, already from the first flights, it became obvious that the astronaut can navigate well in orbit and purposefully observe natural objects. Over time, the work program of cosmonauts became more complicated, space flights became longer and longer, information from space became more and more accurate and detailed.
Many astronauts have noted that they see fewer objects at the beginning of a flight than at the end of a flight. So, cosmonaut V. Sevastyanov said that at first he could hardly distinguish anything from a space height, then he began to notice ships in the ocean, then ships at the berths, and at the end of the flight he distinguished individual buildings on coastal areas.
Already in the first flights, the astronauts saw from a height such objects that they theoretically could not see, since it was believed that the resolution of the human eye was equal to one arc minute. But when people began to fly into space, it turned out that objects were visible from orbit, the angular extent of which is less than a minute. The astronaut, having a direct connection with the Mission Control Center, can draw the attention of researchers on Earth to a change in any natural phenomena and designate the object of shooting, i.e., the role of the cosmonaut-researcher has increased in the observation of dynamic processes. Does a visual review matter for the study of geological objects? After all, geological structures are quite stable, and therefore they can be photographed, and then calmly examined on Earth.
It turns out that a cosmonaut-researcher who has undergone special training can observe a geological object from different angles, at different times of the day, and see its individual details. Before the flights, the cosmonauts specially flew with geologists on an airplane, examined the details of the structure of geological objects, studied geological maps and satellite images.
Being in space and carrying out visual observations, astronauts reveal new, previously unknown geological objects and new details of previously known objects.
The examples given show the great value of visual observations for studying the geological structure of the Earth. However, it must be taken into account that they always contain elements of subjectivism and therefore must be supported by objective instrumental data.
Geologists have already reacted with great interest to the first photographs that cosmonaut G. Titov brought to Earth. What caught their attention in geological information from space? First of all, they got the opportunity to look at the already known structures of the Earth from a completely different level.
In addition, it became possible to check and link disparate maps, since individual structures turned out to be interconnected at large distances, which was objectively confirmed by space images. It also became possible to obtain information about the structure of hard-to-reach regions of the Earth. In addition, geologists have armed themselves with an express method that allows them to quickly collect material on the structure of a particular part of the Earth, to outline objects of study that would become the key to further knowledge of the bowels of our planet.
At present, many "portraits" of our planet have been made from space. Depending on the orbits of the artificial satellite and the equipment installed on it, images of the Earth were obtained at various scales. It is known that space images of different scales carry information about various geological structures. Therefore, when choosing the most informative image scale, one should proceed from a specific geological problem. Due to the high visibility, several geological structures are displayed on one satellite image at once, which makes it possible to draw conclusions about the relationships between them. The advantage of using space information for geology is also explained by the natural generalization of landscape elements. Due to this, the masking effect of the soil and vegetation cover is reduced and geological objects “look” more distinctly on satellite images. Fragments of structures visible on space photographs line up in single zones. In some cases, images of deeply buried structures can be found. They seem to shine through the overlying deposits, which allows us to speak of a certain fluoroscopicity of space images. The second feature of surveys from space is the ability to compare geological objects by daily and seasonal changes in their spectral characteristics. Comparison of photographs of the same area, obtained at different times, makes it possible to study the dynamics of the action of exogenous (external) and endogenous (internal) geological processes: river and sea waters, wind, volcanism and earthquakes.
At present, many spacecraft carry photographs or television devices that take pictures of our planet. It is known that the orbits of artificial Earth satellites and the equipment installed on them are different, which determines the scale of space images. The lower limit of photographing from space is dictated by the height of the orbit of the spacecraft, i.e., a height of about 180 km. The upper limit is determined by the practical expediency of image scales the globe received from interplanetary stations (tens of thousands of kilometers from the Earth). Imagine a geological structure photographed at different scales. On a detailed picture, we can see it as a whole and talk about the details of the structure. As the scale decreases, the structure itself becomes a detail of the image, its constituent element. Its outlines will fit into the contours of the overall picture, and we will be able to see the connection of our object with other geological bodies. Sequentially zooming out, you can get a generalized image, in which our structure will be an element of some geological formation. An analysis of different-scale images of the same regions showed that geological objects have photogenic properties, which manifest themselves in different ways, depending on the scale, time and season of shooting. It is very interesting to know how the image of an object will change with an increase in generalization and what actually determines and emphasizes its “portrait”. Now we have the opportunity to see the object from a height of 200, 500, 1000 km and more. Specialists now have considerable experience in studying natural objects using aerial photographs obtained from altitudes from 400 m to 30 km. But what if all these observations are carried out simultaneously, including ground work? Then we will be able to observe the change in the photogenic properties of the object from different levels- from the surface to space heights. When photographing the Earth from different heights, in addition to purely informational, the goal is to increase the reliability of identified natural objects. On the smallest-scale images of global and partially regional generalizations, the largest and most clearly defined objects are determined. Medium- and large-scale images are used to check the interpretation scheme, to compare geological objects on satellite images and data obtained on the surface of indicators. This allows specialists to give a description of the material composition of rocks emerging on the surface, to determine the nature of geological structures, that is, to obtain concrete evidence of the geological nature of the formations under study. Photographic cameras operating in space are imaging systems specially adapted for photographing from space. The scale of the resulting photographs depends on the focal length of the camera lens and the shooting height. The main advantages of photography are high information content, good resolution, relatively high sensitivity. The disadvantages of space photography include the difficulty of transmitting information to the Earth and taking pictures only in the daytime.
At present, a large amount of space information falls into the hands of researchers thanks to automatic television systems. Their improvement has led to the fact that the quality of images is approaching a space photograph of a similar scale. In addition, television images have a number of advantages: they ensure the prompt transmission of information to Earth via radio channels; shooting frequency; recording video information on magnetic tape and the possibility of storing information on magnetic tape. At present, it is possible to receive black-and-white, color and multi-zone television images of the Earth. The resolution of television pictures is lower than that of still pictures. Television filming is carried out from artificial satellites operating in automatic mode. As a rule, their orbits have a large inclination to the equator, which made it possible to cover almost all latitudes with the survey.
Satellites of the Meteor system are launched into an orbit with an altitude of 550-1000 km. His television system turns on itself after the sun rises above the horizon, and the exposure is automatically set due to changes in illumination during the flight. "Meteor" for one revolution around the Earth can remove an area that is approximately 8% of the surface of the globe.
Compared to a single-scale photograph, a television photograph has greater visibility and generalization.
The scales of television images are from 1: 6,000,000 to 1: 14,000,000, the resolution is 0.8 - 6 km, and the filmed area ranges from hundreds of thousands to a million square kilometers. Good quality pictures can be enlarged by 2-3 times without loss of detail. There are two types of television shooting - frame and scanner. During frame shooting, a sequential exposure of various parts of the surface is carried out and the image is transmitted via radio channels of space communications. During exposure, the camera lens builds an image on a light-sensitive screen that can be photographed. During scanner shooting, the image is formed from separate bands (scans), resulting from a detailed “viewing” of the area by a beam across the movement of the carrier (scanning). The translational movement of the media allows you to get an image in the form of a continuous tape. The more detailed the image, the narrower the shooting swath.
TV pictures are mostly unpromising. To increase the capture bandwidth on the satellites of the Meteor system, shooting is carried out by two television cameras, the optical axes of which are deviated from the vertical by 19°. In this regard, the image scale changes from the satellite orbit projection line by 5-15%, which complicates their use.
Television images provide a large amount of information, making it possible to highlight major regional and global features of the geological structure of the Earth.
After the successful experience of sending Soviet automatic interplanetary stations to the Moon in 1959, in the early 60s. in our country the first launches of spacecraft to the planets were undertaken solar system: in 1961 to Venus and in 1962 to Mars. AMS "Venera-1" covered the distance to Venus in 97 days, AMS "Mars-1" spent more than 230 days on the flight Earth - Mars. Subsequently, the flight time to Venus was increased to 117-120 days, since the rate of approach to the planet was lower, which facilitated the descent in the atmosphere and soft landing on the planet.
Flights to Mars, depending on its position in orbit, take from 6 to 10 months.
The first hard landing on Venus was carried out by the Soviet station "Venera-3" on March 1, 1966, a smooth descent in the atmosphere with the transfer of a large set of scientific data was first made by the AMS "Venera-4" on October 18, 1967, and a soft landing on the surface of Venus manufactured AMS Venera-7 on December 15, 1970. In October 1975, the first artificial satellite of Venus, Venera-9, went into orbit.
The first transmission of images of the surface of another planet (Mars) was carried out by the American spacecraft Mariner-4 in July 1965, the first artificial satellite of Mars was Mariner-9 (USA) on November 14, 1971, and two weeks later The Soviet AMS "Mars-2" and "Mars-3" became artificial satellites of the planet. The first soft landing on the surface of Mars was made by the Mars-3 descent vehicle in early December 1971.
An approach to Mercury with the transmission of images of its surface at close range was carried out by the American spacecraft Mariner-10 in March 1974, an approach to Jupiter was carried out by Pioneer-10 (USA) in December 1974. the same "Mariner-10" in February 1974, the first panoramic images of the surface of Venus were transmitted from it by the Soviet AMS "Venera-9" and "Venera-10" in October 1975, and panoramic images of the surface of Mars were transmitted by American descent vehicles "Viking-1" and "Viking-2", starting from July 20, 1976
The use of spacecraft has greatly expanded the possibility of exploring the planets. The main methods scientific research are the following:
1. Direct photography of the planet from a more or less close distance or small areas of its surface, both from the orbit or flyby trajectory, and from the planet's surface itself. Examples of the application of this method have already been given above. Sometimes shooting was carried out using light filters (Mars-3, Mariner-10).
The resulting images are transmitted to Earth by a method that has long been used in "terrestrial" television: the image is expanded line by line into a chain of signals that are transmitted by an antenna station to Earth, and then a beam in the cathode ray tube of the TV turns the received signal back into an image. This image, photographed from the TV screen, then undergoes lengthy processing aimed at eliminating interference, distortions and defects, as well as special marks from the TV screen, which serve to orient the image, but are unnecessary when considering the view of the planet's surface.
2. Measurement of the pressure and temperature of the planet's atmosphere during descent is carried out using pressure gauges (operating on the principle of an aneroid barometer) and resistance thermometers, density is measured by density meters various types(ionization, tuning fork, etc.). A detailed description of the design of these devices is available in the book by A. D. Kuzmin and M. Ya. Marov "Physics of the planet Venus" (M .: "Nauka", 4974) and in other books and articles listed in the bibliography at the end of the book.
In addition to direct measurements, the parameters of the planet's atmosphere and their change in altitude can be calculated from the rate of descent of the apparatus, since its aerodynamic characteristics are known. Experience has shown that this method gives good agreement with the previous one.
3. Measurement chemical composition atmosphere. Produced using gas analyzers of various types. Typically, each gas analyzer is designed to determine the content of a particular gas.
4. Study upper layers atmosphere by the method of radio transmission. This method consists in the fact that the spacecraft, entering (for an earthly observer) behind the disk of the planet or leaving it, sends a radio wave of a certain length (waves from 8 cm to 6 m are used). Passing through the atmosphere of the planet, the radio wave experiences refraction (refraction) and defocusing due to the fact that the refractive index of the atmosphere decreases with height. Therefore, a wave that has passed through higher layers of the atmosphere is refracted less than one passing through lower layers (Fig. 18).
As a result, the entire beam of radio waves expands and the signal intensity weakens. Depending on the refractive index, the frequency of the signal also changes.
If the planet has an ionosphere, then in the ionospheric layers, on the contrary, the radio beam is focused and the signal is amplified.
Rice. 18. Method of radio translucence (scheme).
Since the spacecraft is moving, the radio beam sent by it, crossing successively the upper and lower layers of the planet's atmosphere (or in reverse order - when leaving behind the planet), experiences either amplification or attenuation, which makes it possible to build a model of the upper layers of the atmosphere, including the ionosphere (in lower layers, the beam weakens so much that it is no longer possible to receive a signal).
5. Spectral observations of the glow of atmospheric gases in ultraviolet rays make it possible to register the most intense, the so-called resonant spectral lines. These include the famous hydrogen line (Lyman-alpha) at a wavelength of 1216 A, an oxygen triplet with a wavelength of 1302-1305 A, and a number of others. Investigation of the glow of these lines Provides information about the composition and density of the atmosphere up to the highest altitudes. Recall that the ultraviolet region of the spectrum is completely inaccessible to observations from the Earth.
6. Measurements of the content of charged particles in the atmosphere and near planetary space using ion traps; measurements of the velocity and flux of charged particles in the planet's magnetosphere.
7. Measurements of the planet's magnetic field strength and study of the structure of its magnetosphere using sensitive magnetometers.
8. Various study methods physical properties and the composition of the soil of the planet; determination of the content of radioactive elements using gamma spectrometers, determination of the dielectric constant of soil using an onboard radar, chemical analysis of soil samples taken by descent vehicles, measurement of soil density with a density meter, etc.
9. Study of the relief of Mars by the intensity of the absorption bands of the main component of its atmosphere - carbon dioxide.
10. The study of the gravitational field of the planet by the movement of its artificial satellites or spacecraft flying past it.
11. Study of the planet's own thermal and radio emission from close distances in a wide range of wavelengths - from microns to decimeters.
This list is far from complete. Some methods will be described or mentioned below when presenting the results of planetary studies. However, already from this list one can see how diverse the methods of space exploration of planets are, what rich opportunities they present to scientists. It is not surprising that in just 15 years these studies have given us an enormous amount of information about the nature of the planets.
Study natural resources planets using space methods
Subject: Exploration of the planet's natural resources using space methods.
Made by: 10th grade student
Municipal General Education
Molodtsova Olga
academic year 2003-2004
Abstract plan
1. Introduction…………………………………………………………..…. 3
2. Geography…………………………………………………….….. 4
3. Ways of studying the Earth………………………………………….. 6
4. Area of study…………………………………………………... 9
5. References……………………………………………….. 10
Introduction.
The rapid development of cosmonautics, successes in the study of near-Earth and interplanetary space have greatly expanded our understanding of the Sun and Moon, Mars, Venus and other planets. At the same time, a very high efficiency of the use of near-Earth space and space technologies was revealed in the interests of many earth sciences and for various branches of the economy. Geography, hydrology, geochemistry, geology, oceanology, geodesy, hydrology, geoscience - these are some of the sciences that are now widely using space methods and research tools. Agriculture and forestry, fishing, land reclamation, exploration raw materials, control and assessment of pollution of the seas, rivers, water bodies, air, soil, protection environment, communications, navigation - this is not a complete list of areas using space technology. The use of artificial Earth satellites for communications and television, operational and long-term weather forecasting and hydrometeorological conditions, for navigation on sea routes and air routes, for high-precision geodesy, the study of the Earth's natural resources and environmental control is becoming more common. In the near future and in the longer term, the versatile use of space and space technology in various areas of the economy will increase significantly.
From the point of view of geography great interest represents space geography. This is the name given to the totality of studies of the Earth from space using aerospace methods and visual observations. The main goals of space geography are the knowledge of the patterns of the outer shell, the study of natural resources for their optimal use, environmental protection, and the provision of weather forecasts and other natural phenomena. Space geography began to develop from the beginning of the 60s, after the launch of the first Soviet and American artificial satellites of the Earth, and then spaceships.
as a continuation and new qualitative development of traditional aerial photography. At the same time, visual observations by spacecraft crews began, also accompanied by satellite imagery. At the same time, after photography and television filming, more complex types of photography began to be used - radar, infrared, radiothermal and other special significance for space geography have some distinctive properties of space photography.
The first of them is a huge visibility. Shooting from satellite and spacecraft is usually carried out from a height of 250 to 500 km.
Other important distinguishing properties of satellite imagery are the high speed of obtaining and transmitting information, the possibility of multiple repetitions of shooting the same territories, which makes it possible to observe natural processes in their dynamics, better analyze the relationship between the components of the natural environment and thereby increase the possibility of creating general geographical and thematic maps. .
As a consequence of the development of space geography, several sub-sectors or directions were identified in it.
Firstly, these are geological and geomorphological studies, which serve as the basis for studying the structure earth's crust. In the USSR, they were also used in engineering and geological research (for example, when laying oil pipeline routes, the Baikal-Amur Railway), in geological exploration and geological survey work (for example, to identify faults in the earth's crust, tectonic structures that are promising for oil and gas) .
Methods of studying the Earth.
The problem of studying natural resources, assessing their reserves, volume and rate of spending, the possibility of their conservation and restoration are becoming increasingly important in our time. The tasks of protecting the environment and combating soil, air, and water pollution have also come to the fore. The need for constant monitoring of the state and rational use of forests, fresh water sources, and wildlife has increased.
Development of crop production, animal husbandry, forestry, fisheries and other areas economic activity Man demanded the application of new, more modern principles of environmental control and much more rapid receipt of its results.
The exhaustion of raw materials located in relatively close and developed by man places has led to the need to find them in remote, hard-to-reach, deep regions. The task arose of covering large areas with versatile exploration.
The main advantages of space tools, when used to study natural resources and control the environment, are: efficiency, speed of obtaining information, it is possible to deliver it to the consumer directly during the reception from the spacecraft, a variety of forms for the visibility of results, cost-effectiveness.
It should be noted that the introduction of space technology by no means excludes the use of aircraft and ground-based facilities in the IPR and SOS. On the contrary, space assets can be more effectively used in combination with them.
In addition to listing the goals, the effectiveness of the use of space technology for solving some problems of urban planning, construction and operation was revealed. highways and other.
objects at a distance, using sensitive elements and devices that are not in direct contact (immediate proximity) with the subject of measurements (research).
This method is based on the important circumstance that all natural and artificial terrestrial formations emit electromagnetic waves containing both their own radiation from the elements of the land, ocean, atmosphere, and solar radiation reflected from them. It has been established that the magnitude and nature of the electromagnetic oscillations coming from them depend significantly on the type, structure and state (on the geometric, physical and other characteristics) of the emitted object.
It is these differences in the electromagnetic radiation of various terrestrial formations that make it possible to use the remote sensing method to study the Earth from space.
In order to reach the sensitive elements of the receiving devices installed on the spacecraft, electromagnetic oscillations coming from the Earth must penetrate the entire thickness earth's atmosphere. However, the atmosphere does not transmit all the electromagnetic energy emitted from the Earth. A considerable part of it, being reflected, returns to the Earth, and a certain amount is scattered and absorbed. At the same time, the atmosphere is not indifferent to electromagnetic radiation of various wavelengths. It passes some vibrations relatively freely, forming “windows of transparency” for them, while it almost completely delays others, reflecting, scattering and absorbing them.
The absorption and scattering of electromagnetic waves by the atmosphere is due to its gas composition and aerosol particles, and depending on the state of the atmosphere, it affects the study from the Earth differently. Therefore, only that part of the electromagnetic radiation from the objects under study that is capable of passing through the atmosphere can reach the receiving device of the spacecraft. If its influence is great, then there are significant changes in the spectral, angular and spatial distribution of radiation.
assessment based on various factors.
The significance of the degree and nature of the influence of the atmosphere on the origin of electromagnetic radiation from the Earth through it for the radiation of natural resources from space is very significant. It is especially important to know the influence of the atmosphere on the passage of electromagnetic waves when studying weakly radiating and poorly reflecting terrestrial formations, when the atmosphere can almost completely suppress or distort the signals characterizing the objects under study.
To study natural resources from space, such a time and conditions are selected when the absorbing and distorting influence of the atmosphere is minimal. When working in the visible range, daylight hours are selected, with an elevation of the angle of the Sun above the horizon of 15 - 35 °, with low humidity, little cloudiness, the possibility of high transparency and low aerosol content of the atmosphere.
Areas of study.
In the field of geology: identification of mineral deposits, identification of promising areas for the extraction of oil, gas, ore, coal, and others; cartographic and geological preparation of large-scale construction; assessment of seismic and volcanic activity, obtaining data for their forecasting; examination of areas of mines and open pits, assessment of damage to vegetation in these areas.
forecasting the flow of water after spring floods, identifying threatened areas and the effectiveness of measures taken to reduce damage from floods; control over changes in the water regime of rivers, in particular, in order to optimize the use of hydroelectric power.
In the field of oceanology, oceanography, fisheries; forecasting of phenomena that affect the efficiency of navigation and pose a danger to coastal areas; assessment of sea routes; change in magnitude and nature of unrest water surface large water areas; observation of the ice situation in high-latitude regions, control of the formation and movement of icebergs; identification of areas rich in plankton, promising effective catches, identification of schools of fish and accumulation of game animals.
In the field of biosphere and environmental protection; assessment of water pollution in specific reservoirs and air in various areas; control of wastewater discharges and pumps in densely populated areas (large cities); control over the location and migration of wild animals.
In the field of agriculture and forestry, land science and land reclamation: operational assessment of development stages, maturity and crop yields; identification of damage to individual areas of fields and forests, establishing the effectiveness of measures aimed at preserving plants, assessing the condition of forest areas and timber reserves, forest inventory; cutting and planting planning; detection of forest fires, control of their development and effectiveness, fire prevention measures; identification of swampiness in certain district irrigation assessments, planning of drainage and melioration works; land use in specific regions, control of irrigated lands, assessment of pastures.
1 "World space exploration". Publishing house-Science. Moscow 1982
Material from the Uncyclopedia
Not so many years have passed since the launch in 1957 of the first artificial Earth satellite, but in this short period space research has managed to take one of the leading places in world science. Feeling himself a citizen of the universe, a person naturally wanted to get to know his world and its environment better.
Already the first satellite transmitted valuable information about the properties of the upper layers of the Earth's atmosphere, about the features of the passage of radio waves through the ionosphere. The second satellite marked the beginning of a whole scientific direction - space biology: a living creature, the dog Laika, went into space for the first time on board. The third orbital flight of the Soviet apparatus was again dedicated to the Earth - the study of its atmosphere, magnetic field, interaction air shell with solar radiation, meteor environment around the planet.
After the first launches, it became clear that space exploration should be carried out purposefully, on a long-term basis. scientific programs. In 1962, the Soviet Union began launching automatic satellites of the Kosmos series, the number of which is now approaching 2,000. phenomena in the upper atmosphere and near-Earth outer space.
Satellites "Electron" and orbital automatic observatories "Prognoz" told about the Sun and its decisive influence on earthly life. Studying our luminary, we also comprehend the secrets of distant stars, get acquainted with the work of a natural thermonuclear reactor, which has not yet been built on Earth. From space, they also saw the "invisible sun" - its "portrait" in ultraviolet, x-ray and gamma rays, which do not reach the Earth's surface due to the opacity of the atmosphere in these parts of the spectrum of electromagnetic waves. In addition to automatic satellites, long-term studies of the Sun were carried out by Soviet and American cosmonauts on orbital space stations.
Thanks to research from space, we better know the composition, structure and properties of the upper layers of the atmosphere and the ionosphere of the Earth, their dependence on solar activity, which made it possible to increase the reliability of weather forecasts and radio communication conditions.
The "cosmic eye" allowed not only to re-evaluate the "external data" of our planet, but also to look into its depths. From orbits, geological structures are better detected, the patterns of the structure of the earth's crust and the distribution of minerals necessary for man are traced.
Satellites allow in a matter of minutes to view huge areas of water, to transmit their images to oceanologists. From the orbits, information is received about the directions and speed of winds, the zones of origin of cyclonic vortices.
Since 1959, the study of the Earth's satellite - the Moon - began with the help of Soviet automatic stations. The Luna-3 station, having circled the Moon, photographed its far side for the first time; "Luna-9" carried out a soft landing on the Earth's satellite. To have a clearer idea of the entire Moon, long-term observations from the orbits of its artificial satellites were necessary. The first of them - the Soviet station "Luna-10" - was launched in 1966. In the autumn of 1970, the station "Luna-16" went to the Moon, which, returning to Earth, brought with it samples of lunar soil rocks. But only long-term systematic studies of the lunar surface could help selenologists understand the origin and structure of our natural satellite. Such an opportunity was soon provided to them by self-propelled Soviet scientific laboratories- moon rovers. The results of space exploration of the Moon provided new data on the history of the origin of the Earth.
The characteristic features of the Soviet program for the study of the planets - regularity, consistency, the gradual complication of the tasks being solved - were especially clearly manifested in the studies of Venus. The last two decades have brought more information about this planet than the entire previous more than three centuries of its study. At the same time, a significant part of the information was obtained by Soviet science and technology. The descent vehicles of the automatic interplanetary stations "Venus" more than once landed on the surface of the planet, probed its atmosphere and clouds. The Soviet stations also became the first artificial satellites of Venus.
Since 1962, Soviet automatic interplanetary stations have been launched to the planet Mars.
Cosmonautics also studies planets more distant from the Earth. Today, television images of the surface of Mercury, Jupiter, Saturn and their satellites can be viewed.
Astronomers, who received space technology at their disposal, naturally, did not limit themselves to studying only the solar system. Their instruments, taken out of the atmosphere, which is opaque to short-wavelength cosmic radiation, aimed towards other stars and galaxies.
The invisible rays coming from them - radio waves, ultraviolet and infrared, X-ray and gamma radiation - carry valuable information about what is happening in the depths of the Universe (see Astrophysics).
Photographic images of the Earth from space began to be obtained from research rockets even before the launch of artificial Earth satellites (AES). The survey of the Earth was carried out from heights of 100-150 km. The shots were very perspective and had an image of the horizon. At the same time, the survey programs already included experiments on choosing the optimal parameters for space photographic systems.
Already on the first satellite images, mountain ranges, outcrops of bedrock, valleys and riverbeds, snow cover and forests were clearly visible.
Filming from rockets has not lost its significance even with the launch of satellites. And at the present time scientists of Belarus are using images obtained during filming from rockets. These images are valuable not only for their information, but also for the fact that they provide a series of different-scale images of the same territory.
Space research, which began in the sixties of the last century, was and is being carried out with such intensity that it has made it possible to accumulate a rich fund of satellite images (CS).
A large, if not huge, number of operational and meteorological satellites, manned spacecraft and orbital stations have been and are keeping a scientific watch. Many of these space objects were or are currently equipped with imaging equipment. The images obtained and obtained in them are extremely diverse depending on the choice of recorded characteristics, the technology for obtaining images and transmitting them to the Earth, the scale of the survey, the type and height of the orbit, etc.
Space images are taken in three main shooting ranges: visible and near infrared (light) range, infrared thermal and radio range.
The first group is the most significant - in the visible and near infrared range, it is divided into three subgroups according to the methods of receiving and transmitting information to Earth: photographic, television and scanner, photo-television images. The variety of images by groups, more or less equivalent in content and volume of transmitted information and image quality, expands the possibilities of using images in certain areas of geographical research.
Geological research is one of the areas where satellite images are most actively used. Already the first photographs from spacecraft have found wide use in the study of stratigraphy and the lithological and petrographic properties of rocks; structural-tectonic study of the territory; prospecting for mineral deposits; study of geothermal zones and volcanism.
One of the important advantages of satellite images is the ability to see new features of the structure of the territory, imperceptible on large-scale images, which refers primarily to the study of large geological structures, filtering small details as a result of the “optical generalization” of the image creates the possibility of spatially linking disparate fragments of large geological formations into a single whole.
A small amount of information obtained by deciphering satellite images refers specifically to the field of structural geology. Plicative structures and discontinuous violations of different orders are well distinguished.
Linear discontinuities are reflected especially well, both with and without displacement of adjacent blocks. In platform areas, they are expressed by weak relief drops, curvature of river channels and erosional forms; in folded mountains, they are deciphered due to shifts of rocks of various lithological composition.
Plicative disturbances - folded structures, complex anticlinoria, ring structures - are also well deciphered on satellite images.
Space images open up fundamentally new possibilities for understanding the deep structure of the lithosphere, making it possible to identify the structures of different depths by a combination of features and compare them with each other. This direction of using satellite images is of great importance in connection with the search for hidden mineral deposits and the tasks of revealing deep seismogenic structures.
On space photographs, the relief does not find a sufficiently complete direct reflection; stereoscopically on stereopairs, only forms of foothill and mountain relief with amplitudes of several tens or hundreds of meters are perceived. However, a good rendering of various indicators of the relief, mainly of the soil and vegetation cover, makes it possible to study the relief in morphological-morphometric and genetic terms.
Different genetic types of relief have their own features of the image on the CS, their deciphering features and decoding indicators. So, for example, the fluvial relief is brightly reflected on the CS in the visible range with a darker background than the surrounding area, and the proluvial alluvial fans of temporary watercourses are clearly visible.
CSs also make it possible to study ancient fluvial forms, for example, ancient erosional tributaries and deltas.
The photographs clearly reflect not only individual valleys, but the entire system of erosional dissection, although individual gullies and ravines can be identified only on photographs of the largest scale. In general, the erosion network is revealed with great completeness. In terms of the completeness of the erosion network display, CSs at a scale of 1:2,000,000 are comparable to topographic maps at a scale of 1:200,000 and 1:100,000.
The CS of the modern and ancient eolian relief make it possible to study the features of the formation and evolution of various forms of relief, expressed in their pattern, and to reveal the dependence of the orientation of forms on the wind regime. At the same time, the images testified to the imperfection of the image of sands on the maps of many regions of the world and the need to involve the SC in compiling maps of desert regions. In addition, the work showed that the CS can be used in the study of not only open, but also closed areas.
The CS shows well karst and subsidence-suffusion landforms, and large-scale images of mountainous areas distinguish even individual landslide-scree alluvial fans, deluvial plumes. Some forms of glacial relief are recognized at the CS: trough valleys with their parallel lines of “shoulders” on the slopes, terminal moraines blocking large valleys, and glacial lakes. The ancient finite moraine relief is often reflected. The coastal form is well displayed on the CS with the characteristic sharpness of the coastlines of the abrasion coast and smooth lines of the accumulative one.
A thorough geomorphological analysis of CS shows the expediency of using them for geomorphological mapping on a medium scale. Images at a scale of 1:2,000,000 can serve as a good basis for field work and drawing geomorphological contours, i.e. mapping on a scale of 1:1,000,000 or smaller.
CSs are also useful for compiling other relief maps, for example, maps of the density of relief dissection, maps of orographic lines and points. When compiling the latter, the nodes of the convergence of the ridges (nodal points), the separation of the characteristic lines of the first and subsequent orders and the entire network of subdivision of mountainous regions, the boundaries of the mountainous and flat territories, etc. are specified from the images.
CS made at a low position of the sun, giving a plastic picture of the relief due to the cut-off mosaic, can be used in the manufacture of hypsometric maps.
Concluding the theoretical part of the discipline "Geomorphology and Geology", it is necessary to remind students of the words of Academician, Professor of St. Petersburg University I. Leman: "A geodesist who draws relief and does not know geomorphology is like a surgeon who performs operations and does not know anatomy."
Questions for self-examination
1. What disciplines is geomorphology divided into?
2. What elements of the form and types of relief do you know?
3. Tell us about the classification of relief by genesis.
4. Tell us about the classification of landforms according to their quantitative characteristics.
5. Give a general description of the relief types.
6. What types of plains do you know by origin?
7. Describe the hilly-morainic relief.
8. Describe the valley-beam relief.
9. Describe the mountainous terrain.
10. Describe the structural relief.
11. Describe the karst relief.
12. Describe the volcanic relief.
13. Describe the aeolian relief.
14. What aircraft are used in space surveys?
15. In what shooting ranges are space images taken?
16. What gives a variety of use of shooting ranges in space photography and what is this range?
17. What are the results of using satellite images in geological research?
18. What are the results of using satellite images in geomorphological research?