flying in craft lighter than air (in distinction to aviation). Until the 1920’s the term “aerostation” meant air travel in general. The origin of the scientific principles of aerostation and the first attempts to rise into the air using the laws of aerostatics belong to the 18th century. As a chronicle testifies, an attempt was made to rise in a large balloon filled with smoke in Russia in 1731 (notes of S. M. Bogolepov, reproduced in the manuscript On Air Flying in Russia FromA.D. 906 by A. I. Sulukadzev). In 1783, L. Euler, a member of the St. Petersburg Academy of Sciences, derived formulas for calculating the lift of aerostats. In that same year the French brothers J. and E. Montgolfier built an aerostat called an air balloon. In this balloon filled with warm air, Pilâtre de Rozier and d’Arlandes lifted off in Paris and made a 25-minute flight on Nov. 21, 1783. At the suggestion of French scientist J. Charles, they began to fill the air balloons with hydrogen, whose lift is more than three times greater than the same volume of heated air. The first flight of two hours and 30 minutes in a hydrogen-filled air balloon 8.5 m in diameter was made (also in Paris) by J. Charles and Robert on Dec. 1, 1783. The balloonists took measurements of air temperature and pressure at an elevation of 3,400 m. In Russia the first flights in an air balloon were made by the Frenchman J. Garnerin on June 20 and July 18, 1803, in St. Petersburg and on Sept. 20, 1803, in Moscow.

After the first flights, which were primarily for entertainment, aerostats began to be used for scientific and military purposes (for studying the atmosphere, geographical research,- and so on). On June 30, 1804, in St. Petersburg the Russian scientist la. D. Zakharov and the Belgian physicist E. Robertson made a flight in an aerostat for the purpose of observing various physical phenomena. The flight lasted three hours and 45 minutes, and they attained an elevation of 2,550 m. Zakharov was the first to use a rope with a weight on the end (guide rope) for braking and soft landing. In February 1805 members of the Russian around-the-world expedition commanded by Admiral I. F. Kruzenshtern, who were in the city of Nagasaki (Japan), first sent an aerostat filled with warm air into flight to observe air currents. In 1849 during Italy’s struggle for independence, the Austrian troops used small (with a volume of 82 cu m) free balloons to drop incendiary and explosive bombs on Venice. In the battle near Solferino in 1859, French balloonist F. Nadar carried on reconnaissance of the deployment of the Austrian troops from a captive balloon by taking photographs of enemy positions. Captive balloons were also used for reconnaissance and adjustment of artillery fire in the USA during the Civil War of 1861-65. During the Franco-Prussian War of 1871 communications between Paris, which was surrounded by the Germans, and the rest of France were set up by means of free balloons. In four months, 3 million letters and dispatches with a total weight of 16,675 kilograms, as well as 150 passengers, were sent on 65 balloons with volumes of 1,000-2,000 cu m. In 1871 the Paris Communards used balloons to spread revolutionary pamphlets.

From the appearance of aerostation until the 1870’s, only free and captive balloons were used. The first plan for a navigable aerostat with propellers, which were rotated manually, was proposed in 1784 by the French military engineer J. Meusnier. In the 1840’s designs for navigable aerostats were proposed by the Russian military engineer I. I. Tretesskii, who had in particular envisaged a rocket engine, and by other inventors. On Sept. 24, 1852, the Frenchman H. Giffard made the first controlled flight at a speed up to 11 km/hr (in windless weather) in an aerostat with a steam engine. In 1869 the permanent Commission on the Use of Aerostation for Military Purposes was formed in Russia. In 1870 at the Ust’-Izhorsk combat engineer camp near St. Petersburg, observations of troop movements and adjustment of artillery fire against targets unseen from the ground were carried out from balloons. In 1875 the Russian scientist D. I. Mendeleev advanced the idea of a “stratostat” and substantiated his choice of designs for some of its parts. In 1880 the aerostation division of the Russian Technical Society was formed. On Jan. 1, 1880, the journal Vozdukhoplavatel’ (Aeronaut) began publication in St. Petersburg and, with interruptions, continued until 1917. In 1885 in St. Petersburg a regular army team of military aeronauts was instituted (in 1887 it was reorganized as the Regular Army Aeronautic Training Depot) and started training ascents and flights in aerostats. Through the initiative of Russian scientists M. A. Rykachev, D. I. Mendeleev, M. M. Pomortsev, and others, the use of aerostats for scientific purposes was renewed. In 1885 at the Main Physical Observatory, which was directed by Academician M. A. Rykachev, meteorological recording instruments were developed, which were taken up in sounding balloons and kites. On Aug. 19, 1887, Mendeleev made a three-hour-and-36-minute flight from the city of Klin in a military balloon at an elevation of 3,350 m; his purpose was to observe a solar eclipse. Rus-sian scientists also used officer training flights for scientific purposes by equipping the aerostats with meteorological instruments. One of the organizers of these flights who often participated in them was the military scholar Professor M. M. Pomortsev. He succeeded in developing a methodology for observations, in improving existing aeronautical instruments, and in creating new ones. The scientific applications of aerostation were not limited to meteorology and aerology. Attempts were made to use free balloons (and later dirigibles, or airships) for investigating inaccessible areas. In 1897, taking off from the island of Spitzbergen in a 5,000-cu-m balloon, the Swedish aeronaut S. Andree and two companions tried to reach the North Pole with a favorable wind, but their attempt was unsuccessful and the aeronauts perished.

In 1887 the Russian scientist K. E. Tsiolkovskii proposed a design for an all-metal frameless dirigible with the possibility of changing the volume during flight and heating the gas. The first successful dirigible flight, at a speed of 22-25 km/hr, was made by the French aeronaut A. Santos-Dumont when, on Nov. 13, 1899, he flew around the Eiffel Tower in Paris and safely returned to his starting place. In 1900 in Germany, F. von Zeppelin’s dirigible made its first flight. This was a rigid dirigible whose design soon became the primary one for dirigibles built in Germany, England, and the USA. The aggressive aspirations of the ruling circles in Germany and the other imperialist powers inspired them to develop aerostation primarily for military purposes. In the aggressive war of 1899-1902 against the Boers, the English troops used spherical captive balloons. In the Russo-Japanese War of 1904-05 both the Russian and the Japanese troops used captive balloons to adjust artillery fire. From the start of the 20th century the more refined kite balloons created by the German A. von Parseval in 1893 began to become common. This type of balloon, with a comparatively streamlined shape, vertical stabilizer, and lateral sails, was stable in the air and permitted observation at wind speeds up to 60 km/hr. During the Italo-Turkish War of 1911-12, in addition to captive kite balloons, the Italian troops for the first time used three semirigid dirigibles for bombing and reconnaissance. Just before and during World War I (1914-18) various types of airships with volumes from 1,500 cu m (the English light airships for detecting submarines) to 68,000 cu m (the German rigid airship for bombing and distance reconnaissance) were adopted in the most developed capitalist countries. The flight speed was 80-130 km/hr at an elevation of 3,500-5,000 m. During the war they participated effectively in naval reconnaissance and coastal defense, in the fight against submarines near ship moorings, and in escorting ships at sea. Captive kite balloons were also used very-effectively for reconnaissance on the field of battle and for adjusting artillery fire. Russia, France, and Germany alone had about 550 such observation balloons on the fronts, with volumes of 820-1,050 cu m, which were capable of ascending to elevations of 600-2,000 m. By the end of the war, kite balloons with a volume of 100-270 cu m began to be sent up in Great Britain, France, and Italy to obstruct aircraft at elevations of 2-4 km.

After the victory of the Great October Socialist Revolution, in December 1917 at the initiative of V. I. Lenin the formation of the first so-called socialist aerostatic detachments was begun in the cities of Petrograd, Moscow, Saratov, Novgorod, and elsewhere. At the start of 1918 the First All-Russian Aerostatic Congress was held. It outlined a program for the development of domestic aerostation. In May 1918 a balloon division was formed at the first Soviet scientific aviation institution, the Moscow Flying Labora-tory, directed by Professor N. E. Zhukovskii. On Aug. 10, 1918, the Field Directorate of Aviation and Aerostation of Field Forces was formed under the auspices of the Revolutionary Military Council of the Republic. Soviet aeronauts participated actively in the battles near Tsaritsyn, Kamyshin, and elsewhere during the Civil War. A new development in the combat use of captive balloons was sending them up for reconnaissance and adjustment of artillery fire from vessels of the river fleets (on the Volga and Dnieper) and also from armored trains. On Mar. 16, 1919, the first balloon ascended from the armored train Chernomorets, which was operating on the Southern Front. The 2nd Aero-static Detachment, in coordination with the armored train Volia, made 75 balloon ascents in two weeks of bitter fighting. On all fronts of the Civil War, Soviet military aeronauts made about 7,000 combat ascents, spending more than 10,000 hours in the air.

On July 27, 1920, a free balloon flight was made in honor of the Second Congress of the Third International. N. D. Anoshchenko, I. I. Olerinskii, and L. E. Kuni ascended in a balloon from Red Square in Moscow, reached an elevation of about 5,000 m, and landed near the city of Bogorodsk. Beginning in 1921, regular balloon flights were made for training and practice, and scientific observations were carried on simultaneously. On Jan. 26, 1921, the Council of Labor and Defense decreed the formation of a special commission to develop a program for aerostatic and aviation development. Several competitions were held for building the best models of aeronautic craft. On Nov. 8-9, 1922, N. D. Anoshchenko, I. I. Meisner, and N. G. Stobrovskii made a flight in a free balloon that covered 1,273 km in 22 hours and ten minutes (from Moscow to Lake Lieks in northern Karelia). This was a record achievement. On Oct. 12, 1924, the Society of Friends of the Air Force held the first all-Union aerostatic competition, in which eight balloons participated (five balloons of 640 cu m, two balloons of 1,437 cu m, and one balloon with a volume of 2,000 cu m). The greatest elevation achieved was 2,485 m and the greatest flight duration was 23 hours and ten minutes.

After the end of World War I airships of various types and with volumes of from 1,400 cu m (semirigid) to 184,000 cu m (rigid) continued to be built in the USA, France, Italy, Germany, and other countries for passenger and freight traffic and for military purposes. The achievements of aerostation in these countries were reflected in the airship flights of the 1920’s. In May 1926 the Norwegian R. Amundsen made a 71-hour flight without landing from the island of Spitzbergen across the North Pole to Alaska in the semirigid dirigible Norge (designed by the Italian engineer U. Nobile) with a volume of 18,500 cu m and equipped with three 185-kilowatt (250-horsepower) engines. In 1928, U. Nobile flew across the North Pole in the same dirigible. In 1929 the German rigid dirigible Graf Zeppelin, with a volume of 105,000 cu m, made a flight around the world with three intermediate landings; the flight took 21 days, covered 35,000 km, and the average flight speed was 177 km/hr. Later, from 1932 to 1937 the dirigible transported 13,110 passengers in 136 flights to South America and seven flights to the USA.

During the 1930’s, flights were made in stratosphere balloons to study the stratosphere. On May 27, 1931, the Belgians A. Piccard and P. Kipfer spent 16 hours in the air in a stratosphere balloon with a volume of 14,300 cu m and ascended to an elevation of 15,780 m; on Aug. 12, 1932, Piccard and M. Cosyns spent 11 hours and 45 minutes in the air in the same balloon and ascended to an elevation of 16,370 m. On Sept. 30, 1933, the Soviet stratosphere balloonists G. A. Prokof ev, K. D. Godunov, and E. K. Birnbaum spent eight hours and 20 minutes in the stratosphere balloon USSR-1 (designed by K. D. Godunov), with a volume of about 25,000 cu m, and they reached an elevation of 19,000 m. On Jan. 30, 1934, the Soviet stratosphere balloonists P. F. Fedoseenko, A. B. Vasenko, and I. D. Usyskin spent seven hours and four minutes in the stratosphere balloon OAKh-1 with a volume of 24,920 cu m and reached an elevation of 22,000 m. On Nov. 11, 1935, the American stratosphere balloonists A. Stevens and O. Anderson ascended to an elevation of 22,066 m in the stratosphere balloon Explorer-2 with a volume of 105,000 cu m. Flights by stratosphere balloons and sounding balloons with automatic radio transmitters at elevations up to 40 km significantly increased the application of aerostation in scientific research.

In the USSR aerostation also became widespread for purposes of sport—in competitions for duration, elevation, and distance of flight. On Mar. 9, 1935, pilot V. A. Romanov and Professor I. A. Khvostikov reached an elevation of 9,800 m in a balloon with an open gondola. On Sept. 3, 1935, I. I. Zykov and A. M. Tropin made a record flight of 91 hours and 15 minutes from Moscow to Aktiubinsk Oblast in a balloon with a volume of 2,200 cu m. From Sept. 29 to Oct. 4, 1937, the Soviet dirigible USSR V-6, with a volume of 19,000 cu m and three 177-kilowatt (240-horsepower) engines, set a world record for duration of flight—130 hours and 27 minutes. On board the airship was a crew of 16; the crew commander was I. V. Pan’kov. Among women, the greatest successes were achieved by A. P. Kondrat’eva, who flew a distance of 481 km in 22 hours and 44 minutes in the spherical balloon USSR VR-31, with a volume of 600 cu m. On Mar. 16, 1941, S. S. Gaigerov and B. A. Nevernov made a record (for duration and distance) flight from Moscow to Novosibirsk Oblast, covering 2,767 km in 69 hours and 20 minutes. By the start of the Great Patriotic War, Soviet aeronauts held 17 of the 24 officially recorded world records in aerostation. Aerostation was widely used during the Great Patriotic War (1941-45). Observation balloons carried on protracted artillery reconnaissance and adjustment of battery fire. Barrage balloons were widely used in the antiaircraft defense systems of Moscow, Leningrad, and other cities against attacks by fascist German aviation. A significant contribution to the creation of improved barrage balloon designs was made by panels of engineers headed by V. N. Arkhangel’skii and K. D. Godunov. A large part in guaranteeing the reliable exploitation of barrage balloons was played by military engineers trained by the professors and teachers headed by Professor V. A. Semenov of the N. E. Zhukovskii Air Force Engineering Academy. In addition to captive balloons, the V-12 non-rigid dirigible, with a volume of 3,000 cu m, was used during the war to ship special cargo. In 1944, the Pobeda dirigible was designed under the direction of engineer B. A. Garf; it had a volume of 5,000 cu m and demonstrated outstanding flight properties. Between 1945 and 1947 this airship was used on the Black Sea to search for minefields, sunken ships, and so on. At the start of the 1950’s flights by domestic air-ships stopped. In the USA and West Germany some nonrigid dirigibles continued to operate until the 1960’s. Most of their flights were made for advertising purposes.

After the end of the Great Patriotic War, sport and scientific aerostation continued to develop in the Soviet Union. On July 3, 1945, S. A. Zinoveev and A. M. Borovikov ascended in the balloon USSR VR-70, with a volume of 600 cu m, for scientific observations of atmospheric electricity, and on July 9, 1945, they observed a solar eclipse from the balloon USSR VR-63. On Nov. 11, 1945, G. I. Golyshev and M. I. Volkov ascended to an elevation of 11,500 in the substratosphere balloon VR-79, with a volume of 2,700 cu m, for the purpose of studying physical phenomena in the upper layers of the atmosphere. On Apr. 27, 1949, P. P. Polosukhin and A. F. Krikun ascended to an elevation of 12,100 m in the balloon USSR VR-79, with a volume of 2,700 cu m. On Oct. 25-28, 1950, Soviet aeronauts S. A. Zinoveev, S. S. Gaigerov, and M. M. Kirpichev completed a flight in the same balloon from Moscow to Kazakhstan, flying about 3,200 km in a straight line in 84 hours and 24 minutes. The flight was made at an elevation of more than 5,000 m. The 1950’s were marked by a great leap forward in the study of atmospheric physics, particularly the laws of movement of air masses. The so-called jet streams in the atmosphere were discovered. It became possible to make maps of jet streams over the entire globe and to forecast a balloon’s flight path from the moment of its launching throughout several days of flight. Simultaneously with the expansion of knowledge of the physics of the atmosphere there were fundamental changes in aerostatic technology. The chemical industry turned out new plastic materials for making balloon envelopes (polyethylene, polyethylene terephthalate, and others). These materials are transparent, strong, frost-resistant, and very light (1 sq m of such film weighs 30-50 g) and are heated very little by the sun’s rays. In a balloon made of such materials it is possible to reach an elevation of about 40 km and fly for more than 15 days. Achievements in radio technology, electronics, automation, precision instrument manufacture, and other fields made it possible to build unmanned free balloons, called automatic aerostats, which fly and carry out complex research programs reliably. They are used to study air jet streams, for geographical and biomedical research in the lower layers of the stratosphere, as pads for launching meteorological rockets and setting up altitude telescopes, and so on.