Dmitry Yevgenyevich Okhotsimsky () was a Russian engineer in the former

Soviet space program The Soviet space program () was the state space program of the Soviet Union, active from 1951 until the dissolution of the Soviet Union in 1991. Contrary to its competitors (NASA in the United States, the European Space Agency in Western Euro ...

who pioneered the studies in robotics, controls, and space ballistics. He wrote fundamental works in applied

celestial mechanics Celestial mechanics is the branch of astronomy that deals with the motions of objects in outer space. Historically, celestial mechanics applies principles of physics (classical mechanics) to astronomical objects, such as stars and planets, to ...

spaceflight Spaceflight (or space flight) is an application of astronautics to fly objects, usually spacecraft, into or through outer space, either with or without humans on board. Most spaceflight is uncrewed and conducted mainly with spacecraft such ...

dynamics and

robotics Robotics is the interdisciplinary study and practice of the design, construction, operation, and use of robots. Within mechanical engineering, robotics is the design and construction of the physical structures of robots, while in computer s ...

Biography

Okhotsimsky was born and lived his whole life in

Moscow Moscow is the Capital city, capital and List of cities and towns in Russia by population, largest city of Russia, standing on the Moskva (river), Moskva River in Central Russia. It has a population estimated at over 13 million residents with ...

. His father, Yevgeny Pavlovich Okhotsimsky, was an accountant/auditor, his mother a housewife. Okhotsimsky was very attached to his parents and always lived together with them. At the age of fifteen he suffered

diphtheria Diphtheria is an infection caused by the bacteria, bacterium ''Corynebacterium diphtheriae''. Most infections are asymptomatic or have a mild Course (medicine), clinical course, but in some outbreaks, the mortality rate approaches 10%. Signs a ...

in a hard form and was prohibited from any sports or physical activity. Nevertheless, he showed his whole life remarkable energy and good health, and was actively working until his death at the age of 84. He entered the Department of

Mechanics Mechanics () is the area of physics concerned with the relationships between force, matter, and motion among Physical object, physical objects. Forces applied to objects may result in Displacement (vector), displacements, which are changes of ...

and

Mathematics Mathematics is a field of study that discovers and organizes methods, Mathematical theory, theories and theorems that are developed and Mathematical proof, proved for the needs of empirical sciences and mathematics itself. There are many ar ...

of the

University of Moscow Moscow State University (MSU), officially M. V. Lomonosov Moscow State University,. is a public research university in Moscow, Russia. The university includes 15 research institutes, 43 faculties, more than 300 departments, and six branches. Al ...

in 1939. When

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

broke, the department was temporarily closed. He participated in the building of defense installations around Moscow, worked at the munitions factory. In 1941 he was conscripted to the Red Army but was dismissed in 1942 for vision problems (severe nearsightedness) and returned to the University. In 1946 he presented a paper about the optimization of the

missile A missile is an airborne ranged weapon capable of self-propelled flight aided usually by a propellant, jet engine or rocket motor. Historically, 'missile' referred to any projectile that is thrown, shot or propelled towards a target; this ...

flight, where he was able to find an

analytical solution In mathematics, an expression or equation is in closed form if it is formed with constants, variables, and a set of functions considered as ''basic'' and connected by arithmetic operations (, and integer powers) and function composition. C ...

using an original technique of

calculus of variations The calculus of variations (or variational calculus) is a field of mathematical analysis that uses variations, which are small changes in Function (mathematics), functions and functional (mathematics), functionals, to find maxima and minima of f ...

, a precursor in some respects to what was later formulated in a more general form as the

Pontryagin's maximum principle Pontryagin's maximum principle is used in optimal control theory to find the best possible control for taking a dynamical system from one state to another, especially in the presence of constraints for the state or input controls. It states that it ...

(from

Lev Pontryagin Lev Semyonovich Pontryagin (, also written Pontriagin or Pontrjagin, first name sometimes anglicized as Leon) (3 September 1908 – 3 May 1988) was a Soviet mathematician. Completely blind from the age of 14, he made major discoveries in a numbe ...

). In 1949 he joined the Mathematical Institute of the

Russian Academy of Sciences The Russian Academy of Sciences (RAS; ''Rossíyskaya akadémiya naúk'') consists of the national academy of Russia; a network of scientific research institutes from across the Russian Federation; and additional scientific and social units such ...

, where was working in the department of Applied Mathematics led by

Mstislav Keldysh Mstislav Vsevolodovich Keldysh (; – 24 June 1978) was a Soviet mathematician who worked as an engineer in the Soviet space program. He was the academician of the Academy of Sciences of the Soviet Union (1946), President of the Academy of Sc ...

, the future President of the Russian Academy of Sciences. Keldysh was an active member of the think tank behind the space program and his support was instrumental for active integration of Okhotsimsky and his group in space projects. Later the department of Keldysh became a separate institute currently known as the

Keldysh Institute of Applied Mathematics The Keldysh Institute of Applied Mathematics () is a research institute specializing in computational mathematics. It was established to solve computational tasks related to government programs of nuclear and fusion energy, space research and m ...

and the group of Okhotsimsky became a department in this institute, which he was leading until his death.

Space ballistics

Since his first student work, Okhotsimsky was interested in analytical and numerical solution of variational problems to which the optimization of

space mission Spaceflight (or space flight) is an application of astronautics to fly objects, usually spacecraft, into or through outer space, either with or without humans on board. Most spaceflight is uncrewed and conducted mainly with spacecraft such a ...

can be reduced: how the mission can achieve its target with the minimal total fuel consumption (possibly combined with other criteria and restrictions). Using first Soviet computers (such as

Strela computer Strela computer () was the first mainframe vacuum-tube computer manufactured serially in the Soviet Union, beginning in 1953. Overview This first-generation computer had 6200 vacuum tubes and 60,000 semiconductor diodes. Strela's speed was 200 ...

, he worked with his colleagues to develop new generation of

numerical method In numerical analysis, a numerical method is a mathematical tool designed to solve numerical problems. The implementation of a numerical method with an appropriate convergence check in a programming language is called a numerical algorithm. Mathem ...

s and principles of programming. After the launch of the first satellite he published a few papers were the mathematical aspects of the launch and evolution of the orbit were analyzed. Okhotsimsky's leadership was instrumental in the development within his department of the remarkable group of young talents collectively nicknamed "Keldysh boys". Many of them became well-known, such as Efraim Akim, Timur Eneev and Mikhail Lidov. Okhotsimsky contributed to the planning of multiple space missions including launches to

Moon The Moon is Earth's only natural satellite. It Orbit of the Moon, orbits around Earth at Lunar distance, an average distance of (; about 30 times Earth diameter, Earth's diameter). The Moon rotation, rotates, with a rotation period (lunar ...

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

and

Venus Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker ...

. His analysis of the first failed docking attempts on

Soyuz spacecraft Soyuz () is a series of spacecraft which has been in service since the 1960s, having made more than 140 flights. It was designed for the Soviet space program by the Korolev Design Bureau (now Energia). The Soyuz succeeded the Voskhod spacecraf ...

helped to quickly find a reason of mechanical instability and develop successful docking techniques. Together with Yuri Golubev and Yuri Sikharulidze he developed a concept of a dual-entry

aerodynamically Aerodynamics () is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dynamics and its subfield of gas dynamics, and is an important domain of ...

controlled landing

algorithm In mathematics and computer science, an algorithm () is a finite sequence of Rigour#Mathematics, mathematically rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algo ...

of a

spacecraft A spacecraft is a vehicle that is designed spaceflight, to fly and operate in outer space. Spacecraft are used for a variety of purposes, including Telecommunications, communications, Earth observation satellite, Earth observation, Weather s ...

where the two-stage entry was used to reduce speed and achieve an accuracy of landing of a few km. He developed the methods on the passive stabilization of satellites using the gravity gradient and the non-sphericity of the tensor of inertia.

Rocket design

Okhotsimsky's team, along with a group managed by

Mikhail Tikhonravov Mikhail Klavdievich Tikhonravov (29 July 1900 – 3 March 1974) was a Soviet engineer who was a pioneer of spacecraft design and rocketry. Mikhail Tikhonravov was born in Vladimir, Russia. He attended the Zhukovsky Air Force Academy from 1922 ...

at NII-4, did analysis and optimization of multi-stage rocket designs. Okhotsimsky studied the general problem of how rockets could increase their range by dropping parts of their construction during flight. This included sequential stages and parallel "packet" rockets and schemes involving the pumping of fuel between stages during flight. This led directly to the design of the R-7 missile and the exact proportions of its strap-on booster stages.

Robotics

In the middle of the 1970s Okhotsimsky became interested in

, especially in the modeling and control of

insect Insects (from Latin ') are Hexapoda, hexapod invertebrates of the class (biology), class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (Insect morphology#Head, head, ...

-like walking. A few successful models of 6-legged walking robots were created including systems with autonomous vision able to climb the stairs and handle complicated terrain.Okhotsimsky D.E., Golubev Yu. F. Mechanis and control of the automatic walking system, Nauka,

, 1974 In the work of Okhotsimsky and his school realistic mechanical modeling of the motion was typically combined with sophisticated

s adapted to the context of a particular task. He usually advocated a "from the bottom up" approach aimed at first handling particular low-level problems and then moving to assembling a more general setup. He thought that this is the way the nature works in the making of live creatures.

Positions and social activity

Okhotsimsky combined the talents of a scientist and an administrator. His career was closely linked to the section of Mechanics and Control of the Soviet/

, of which he was a deputy-secretary. Parallel to his main work in the Keldysh Institute of Applied Mathematics, he was appointed in 1962 a chair of Theoretical Mechanics at the Department of Mathematics and Mechanics at the

Moscow State University Moscow State University (MSU), officially M. V. Lomonosov Moscow State University,. is a public university, public research university in Moscow, Russia. The university includes 15 research institutes, 43 faculties, more than 300 departments, a ...

and performed both functions until his last days. He was always striving to find practical forms of cooperation between the Academy of Science and the University. Until his last days he remained a staunch supporter of the leading role of the Academy of Science as a center of fundamental research in Russia. Okhotsimsky was one of the 5 initiators of the creation of the Department of Control and Applied Mathematics at the Moscow Institute of Physics and Technology.

Awards and honors

*Member of the

Corresponding Member The corresponding member is one of the possible membership types in some organizations, especially in the learned societies and scientific academies. This title existed or exist in the Soviet Union, GDR, Polish People's Republic, Czechoslovak S ...

since 1960,

Academician An academician is a full member of an artistic, literary, engineering, or scientific academy. In many countries, it is an honorific title used to denote a full member of an academy that has a strong influence on national scientific life. Accor ...

since 1991 *Foreign Member of the

Serbian Academy of Sciences and Arts The Serbian Academy of Sciences and Arts (; , SANU) is a national academy and the most prominent academic institution in Serbia, founded in 1841 as Society of Serbian Letters (, DSS). The Academy's membership has included Nobel Prize, Nobel la ...

since 2000 *

Lenin Prize The Lenin Prize (, ) was one of the most prestigious awards of the Soviet Union for accomplishments relating to science, literature, arts, architecture, and technology. It was originally created on June 23, 1925, and awarded until 1934. During ...

(1957) *

Hero of Socialist Labour The Hero of Socialist Labour () was an Title of honor, honorific title in the Soviet Union and other Warsaw Pact countries from 1938 to 1991. It represented the highest degree of distinction in the USSR and was awarded for exceptional achievem ...

(1961) *Two

Orders of Lenin The Order of Lenin (, ) was an award named after Vladimir Lenin, the leader of the October Revolution. It was established by the Central Executive Committee on 6 April 1930. The order was the highest civilian decoration bestowed by the Soviet ...

(1956, 1961) *Two Orders of the Red Banner of Labour (1970, 1981) *

Order of the October Revolution The Order of the October Revolution (, ''Orden Oktyabr'skoy Revolyutsii'') was instituted on 31 October 1967, in time for the 50th anniversary of the October Revolution. It was conferred upon individuals or groups for services furthering communis ...

(1975) *

USSR State Prize The USSR State Prize () was one of the Soviet Union’s highest civilian honours, awarded from its establishment in September 1966 until the dissolution of the USSR in 1991. It recognised outstanding contributions in the fields of science, mathem ...

, 1970 (for his contribution to the lunar mission "Luna-16") *Gold Keldysh medal, 2001 (awarded by the

for works in mechanics) * Minor planet 8062 discovered by astronomer

Nikolai Chernykh Nikolai Stepanovich Chernykh ( rus, Никола́й Степа́нович Черны́х, , nʲɪkɐˈlaj sʲtʲɪˈpanəvʲɪtɕ tɕɪrˈnɨx, links=yes; 6 October 1931 – 25 May 2004Казакова, Р.К. Памяти Николая Сте ...

on March 13, 1997 was named Okhotsymskij in his honor.

Published works

*Охоцимский Д. Е., Голубев Е. Ф., Сихарулидзе Ю. Г., Алгоритм управления космическим аппаратом при входе в атмосферу - М, Наука, 1975. *Охоцимский Д.Е., Голубев Ю.Ф.Механика и управление движением автоматического шагающего аппарата - М., Наука, 1984. *Охоцимский Д.Е.,Сихарулидзе Ю.Г. Основы механики космического полета. - М., Наука, 1990

References

External links

Obituary article
at the

(in Russian)
Historical account of how the orbit of the first satellite was measured and computed (In Russian)Online version of the memoirs
of

Nikita Moiseyev Nikita Nikolayevich Moiseyev (Russian: Никита Николаевич Моисеев) (23 August 1917 – 29 February 2000) was a Soviet and Russian mathematician, full member of the Soviet and Russian Academies of Sciences and of the Interna ...

B.E. Chertok "Rockets and people" online, in Russian
* ttp://www.ras.ru/win/db/show_per.asp?P=.id-776.ln-ru.dl-.pr-inf.uk-0 Okhothimsky's page on the siteof the

Okhotsimsky's biography information on the site
of the

Department of Control and Applied Mathematics at the Moscow Institute of Physics and Technology, history notesAkim, E. L., Golubev, Yu. F., Platonov, A. K., Eneev, T. M. ''D. E. Okhotsimsky as a leader of the scientific school of space flight mechanics'' Cosmic Res (2006) 44: 183-186
{{DEFAULTSORT:Okhotsimsky, Dmitry 1921 births 2005 deaths 20th-century Russian engineers 20th-century Russian mathematicians 21st-century Russian engineers 21st-century Russian mathematicians Engineers from Moscow Mathematicians from Moscow Communist Party of the Soviet Union members Corresponding Members of the USSR Academy of Sciences Foreign members of the Serbian Academy of Sciences and Arts Full Members of the Russian Academy of Sciences Heroes of Socialist Labour Recipients of the Lenin Prize Recipients of the Order of Lenin Recipients of the Order of the October Revolution Recipients of the Order of the Red Banner of Labour Recipients of the USSR State Prize Early spaceflight scientists Russian aerospace engineers Russian mechanical engineers Russian space program personnel Soviet aerospace engineers Soviet mechanical engineers Soviet space program personnel Burials in Troyekurovskoye Cemetery