Space Photography

photography of the earth, heavenly bodies, nebulas, and various cosmic phenomena with instruments located outside the earth’s atmosphere. Photographs of the earth’s surface made from space are distinguished by the fact that, although they provide a representation of terrain as a whole (and a more objective representation than do maps), they encompass very large areas (from tens of thousands of square kilometers to the entire globe in one photograph). This makes possible the use of space photographs to study the basic structural, regional, zonal, and global characteristics of the atmosphere, lithosphere, hydrosphere, biosphere, and landscape of our planet as a whole. With space photography an area may be photographed repeatedly during the same flight—that is, after short time intervals—which makes possible the study of the dynamics of natural phenomena that are periodic (daily, seasonal, and so on) and occasional (eruption of volcanoes; forest fires), as well as various manifestations of human economic activity (harvesting, the filling of reservoirs, and so on). Space photography provides a basis for the development of comprehensive measures to combat pollution of the air, land, and seas.

The first photographs from space were taken from rockets in 1946; the first photographs from artificial earth satellites were made in 1960, and the first from a manned spacecraft were taken in 1961 by Iu. A. Gagarin. At first, space photography was limited to photography in the visible range of the spectrum of electromagnetic waves, with direct delivery of the photographs to the earth (primarily in containers, by parachute). In addition to black-and-white and color photographs and television pictures, infrathermal, microwave, radar, spectrometric, and other types of electronic photography are used. The equipment is fundamentally the same as used in aerial photography.

The methods of space photography for the earth are (1) photographs from altitudes of 150–300 km, taken from short-term vehicles, with return of exposed film and recordings to earth; (2) photographs from altitudes of 300–950 km from long-term vehicles (in orbits in which the satellite is, in effect, always above the lighted part of the earth), with transmission of the images to the earth using radio and television systems; (3) photographs from an altitude of approximately 36,000 km from synchronous satellites, with delivery of the photographic information to earth using radio and television systems; (4) photographs from unmanned interplanetary probes at a series of consecutively increasing altitudes (for example, from the Zond probe at 60,000 and 90,000 km); (5) photographs of the earth from the surface of the moon and nearby planets taken automatically by recording and transmitting photoelectronic radio-television equipment sent there; (6) photographs from manned spacecraft and manned orbital stations (the first of which was the Soviet Salyut station).

The average scale of space photographs is 1:1,000,000 to 1:10,000,000. The detail of the image of the earth’s surface on photographs from space is significant. For example, when examining a photograph on a scale of 1:1,500,000 (taken from the Salyut station) under 10-power magnification, the main hydro-graphic and road networks, the contours of fields, medium settlements, and all cities (with their street patterns) are visible.

Modern areas of application of space photography include meteorology (the study of clouds, snow cover, and so on); oceanography the study of currents, the bottoms of shallow bodies of water, and so on); geology and geomorphology (particularly very long formations); the study of glaciers, swamps, deserts, and forests; tabulation of cultivated land; natural and economic re-gionalization of territories; and the creation and updating of small-scale topical and general geographic maps. The immediate prospects for practical use of space photography to study, develop, and protect the geographical environment and natural resources of the earth are associated with multichannel photography (in several spectral bands simultaneously, with identical illumination of the terrain) from orbital scientific space laboratories. This increases the variety and volume of information obtained and makes possible automatic processing, particularly when interpreting space photographs.