Extra-atmospheric astronomy

Probably, the beginning of extra-atmospheric astronomy can be associated with the creation of the first telescope by Galileo . Almost immediately, it was found that moving the telescope away from the Earth’s surface significantly improves the image of celestial objects (however, for the distances accessible to astronomers of that time, the main contribution to image improvement is not due to a decrease in atmospheric pressure, but to the movement of the instrument in an area with a lower concentration of dust and other contaminants).

Further successes in extra-atmospheric astronomy are associated with the use of high-altitude balloons capable of reaching heights of 40-50 km. The use of balloons made it possible to rise above the surface layers of the atmosphere saturated with water vapor and significantly overcome the ozone layer (the maximum concentration of ozone is observed at an altitude of about 27 km, at which the molecular concentration of ozone is approximately 3 10 ⁻⁶ ). Reaching these heights made it possible to perform separate measurements using radiation having a wavelength of more than 200 nm. The next stage in the success of extra-atmospheric astronomy is due to the beginning of the widespread use of rockets that were capable of reaching a height of 100 km, which allowed them to completely go beyond the ozone layer and expanded the spectrum of electromagnetic radiation available for research to 80 nm. In addition, the achievement of these heights opened up the possibility of individual x-ray studies. Despite the fact that the use of rockets made it possible to double the height to which astronomical instruments could be raised, the short flight time, low flight mass and the difficulty of using slow shutter speeds for gyroscopic stabilization of the rocket led to the fact that for a long time balloons and rockets were used in parallel with each other . The main result of this stage of extra-atmospheric astronomy is obtaining an image of the Sun in the region of wavelengths less than 300 nm. And finally, the rapid development of extra-atmospheric astronomy was facilitated by the beginning of the space age, which allowed not only to move observational means far beyond the Earth’s atmosphere, but also to place them in close proximity to the objects being studied.

The main objects of interest for researchers at the initial stage of development of radio astronomy were the Earth and the Sun. The first ever astronomical instruments put into low Earth orbit were installed on the Soviet satellite Sputnik-2 , launched in the USSR on November 3, 1957 . In addition to observations of the sun in the region of hard radiation (0.1-12 nm), Sputnik-2 equipment made it possible for the first time to detect the presence of the Earth's radiation belts (it is interesting to note that amateur radio operators from around the world, recording the signals of Sputnik-3, occupied the important role in determining the boundaries of the Earth's radiation belts studying the boundaries of radiation belts). Subsequent experimental observations of the Sun made by the USSR in 1957-1960 yielded data on the plasma temperature in the corona. The presence of solar wind was first detected by the automatic stations Luna-1 and Luna-2. A systematic and lengthy observation of solar activity (begun by the USSR in the 60s) made it possible to establish a connection between the change in the observed characteristics of the Sun and the physical processes taking place in it. The first image of the solar corona, made in the region of wavelengths corresponding to the x-ray range, was obtained by specialists of Naval Research Laboratory ( USA ). The equipment they used made it possible to obtain a resolution of 0.1 of the solar disk. Despite this relatively low resolution, the fundamental result of the study was the discovery of the anisotropy of the short-wave radiation of the solar corona and the registration of several active zones (which roughly coincided with the zones-sources of decimeter radiation). The next stage in the development of extra-atmospheric astronomy is associated with the study of various bodies of the solar system. One of the fundamental tasks that had to be solved to implement these studies was to achieve a second cosmic velocity. After a series of failures, this task was solved by AFM Luna-1. Due to a software error, the flight program was partially implemented, and among the flight results, the discovery of the Earth’s external radiation belt and the absence of the moon’s magnetic field can be noted. The first image of the far side of the moon was given by the AFM Luna-3, which, in addition to obtaining photographic information about the moon, made it possible to develop a system for stabilizing and orienting spacecraft, which was crucial for the subsequent development of extra-atmospheric astronomy. Almost simultaneously with the exploration of the moon, attempts were made to study Venus. After a series of failures of the Soviet aircraft (which nevertheless made it possible to obtain the most important technological information about the features of the operation of aircraft in space), the flight of the American Mariner-2 turned out to be successful, which was able to perform thermometric measurements of the Venusian atmosphere, specified the period of its revolution and made measurements of the magnetic field .

• Radio astronomy

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