Computing in the Soviet Space Program











Anatoly Krivonosov


Anatoly Ivanovich Krivonosov,

the chief designer of onboard

computers at Khartron

Khartron: Computers for Rocket Guidance Systems

by Anatoly Krivonosov

from Boris Malinovsky, History of Computer Science and Technology in Ukraine

Translated from the Russian by Slava Gerovitch

Malinovsky's introduction: The Khar'kov research-and-production association Khartron (formerly Elektropribor), established in 1959, has been one of the three organizations in the former Soviet Union (and the only one in Ukraine) that developed guidance systems for rockets and spacecraft, including onboard computers. For 40 years Khartron has remained a leading contractor for guidance systems, onboard and ground computer complexes, and advanced electronic equipment for various types of rockets and spacecraft. During those years, Khartron developed guidance systems for the intercontinental ballistic missiles SS-7, SS-8, SS-9, SS-15, SS-18, SS-19, the most powerful in the world delivery vehicle Energia, the delivery vehicle Tsiklon, the orbital modules Kvant, Kvant-2, Kristall, Priroda, Spektr, and 152 satellites of the Kosmos series.

The first guidance systems were based on analog and electro-mechanical devices; after 1964, they were based on electronic calculation-solving devices. In the latter period, the association Khartron provided modern, large-scale production of modules, multi-layered printed-circuit boards, and ferrite core memory, and it solved complex scientific and technical problems of interference shielding, high reliability, and the stability of key parameters of onboard computer facilities over the entire period of operation (10 years and more). A whole pleiad of talented scientists and engineers (V.P. Leonov, G.S. Bestan', D.N. Merzliakov, D.M. Smurnyi, and others) has emerged. The first head of the department of onboard equipment design, created in 1962, was A.N. Shestopal. From 1966 to 1992 this department was headed by A.I. Krivonosov. The chief executive and chief designer of missile complexes in the research-and-production association Khartron from 1960 to 1986 was Vladimir Grigor'evich Sergeev.

Anatoly Ivanovich Krivonosov, Doctor of Engineering, the chief designer of onboard computer equipment and a laureate of the Lenin Award and the State Award, shares memories of his work at Khartron:

By the mid 1960s it had become clear that the idea of building guidance systems on the basis of analog and discrete calculation-solving devices had no future. Further improvement of intercontinental ballistic missile guidance systems required a sharp increase in the amount of information processed on board a missile in real time. It also required a change in the approach to procedural tests of missile systems. Such tests were carried out on mobile testing equipment, which was installed on several trucks and was complex, expensive, and difficult to operate.

A revolutionary step at this point was the construction of missile guidance systems on the basis of onboard electronic computers, which provided the functioning of a missile complex during ground tests and during the flight. This step made it possible to simplify the ground equipment; it could now be placed at the top of missile silos instead of truck convoys. The possibility of using more complex calculation algorithms made it possible to raise significantly the accuracy of launches.

At the Khartron theoretical department led by Ia.E. Aizenberg, Doctor of Engineering and a laureate of the Lenin Award, a new section was created (head B.M. Konorev) for the development of architecture specifications and technical parameters of onboard computers and for the development of software. It was necessary to create not only a new methodology for the development of all algorithms and flight programs for ground tests, but also new technologies for designing technical tools, including simulation stands and an automated programming system. Initially Khartron developed guidance systems with onboard computers on two parallel tracks:

(1) based on an onboard computer designed by the Scientific Research Center for Electronic Computer Technology, the leading computer design organization of the USSR Ministry of Radio Industry;

(2) based on an onboard computer of its own design.

In April 1967, at a meeting of the top management of Khartron, the chief executive and chief designer Vladimir Grigor'evich Sergeev proposed to discuss and resolve the question of concentrating efforts on one of these directions. All the heads of leading departments and sections (Ya.E. Aizenberg, A.I. Krivonosov, B.M. Konorev, A.S. Gonchar, and others) supported the use of the Khartron computer. If the other computer was chosen, they argued, it would be practically impossible to implement any changes in the software, and this would slow down drastically the development of new guidance systems. The decision was made unanimously. As early as 1968, the first experimental model of an onboard computer on hybrid modules was tested. In just 6 months, its three-channel modified version on monolithic integrated circuits appeared.

In 1971 the Soviet Union for the first time launched the new 15А14 missile with a guidance system that included an onboard computer. The technical parameters of this computer (16-bit word length, 512 or 1024-word RAM, 16K-word read-only memory, and the speed of 100,000 ops) were chosen very well and implemented successfully, and its technological base was very reliable. As a result, this computer had a uniquely long life -- about 25 years -- and its slightly modernized version is still in operation and on active duty today. In order to meet strict size requirements, for the first time in the computer industry Khartron specialists developed hybrid micro-assembly of RAM control circuits, flat micro-modules with galvanic junction for synchronization devices, and multi-layered printed-circuit boards made by the open contact platform method.

In 1979 the 15A18 and the 15A35 missiles with unified onboard computer complexes were placed on active duty. For the guidance systems of these "super-products," for the first time in the Soviet Union, Khartron specialists developed a new technology of software debugging, which included the so-called "electronic start-up": at a special complex that included the BESM-6 computer and certain modules of the missile guidance system, they simulated a missile flight and tested the responses of the guidance system to various disturbances. This technology provided efficient and complete testing of flight tasks. A group of the "electronic start-up" developers (Ya.E. Aizenberg, B.M. Konorev, S.S. Koruma, I.V. Vel'bitskii, and others) received the State Award of the Ukrainian Republic.

In the subsequent four years, they created four more series of onboard computers with some of the best in the Soviet Union technical and operational parameters, and also an efficient technology of software development on a par with foreign analogues.

One of our "highlights" was an original system of dynamic correction of programs (authors B.M. Konorev, V.P. Kamenev, A.V. Bek, Yu.M. Zlatkin, and A.I. Bondarev). While programs in read-only memory were rigidly "stitched" by way of "braids" that were inserted in U-shaped ferrite cores, this system made it possible to introduce necessary changes in the software at all stages from pre-flight tests to the work on the orbit.

The operational experience with the first onboard computers demonstrated the need to improve the structural methods of ensuring reliability. Khartron scientists and engineers (A.I. Krivonosov, V.I. Spiridonov, Iu.G. Nesterenko, I.I. Kornienko, V.V. Shein, A.V. Sychev, N.F. Mekhovskoi, and others) developed theoretical principles of the synthesis of highly reliable computing structures with multi-level majority and adaptation. These principles laid the basis for future generations of onboard computers.

In 1984-1988, Khartron developed the guidance system for the SS-18, a unique superpowerful missile known in foreign classifications as "the Satan." This system incorporated all the best technical solutions found in previous systems, as well as some totally new ideas:

  • providing serviceability after a nuclear explosion during the flight;
  • highly precise individual control of combat elements;
  • "direct" method of targeting that did not require prior formulation of the flight mission;
  • remote targeting; and so on.

These new ideas were implemented with the help of a new powerful onboard computer complex using "burning-out" transistor-based read-only memory and electronic RAM.

Most basic parts were manufactured at the Minsk production association "Integral" according to the specified level of radiation resistance. Besides the standard blocks, the onboard computer complex included, for the first time in the Soviet Union, a specialized memory unit on ferrite cores with internal diameter 0,4 mm through which 3 wires thinner than human hair were threaded. Also for the first time in Soviet Union, a memory unit on cylindrical magnetic domains was developed specifically for a certain type of combat equipment, and it passed flight tests.

One of the most difficult problems was the construction of an onboard multi-machine computer complex for the delivery vehicle Energia. This complex solved most complicated problems of stabilization, vehicle lead-out (in case extraordinary situations occurred in the control of numerous engine units), emergency protection of engines, and soft landing of initial stages ("side blocks"). The high requirements for reliability and failure-free operation were complicated by the use of oxygen and hydrogen components in the delivery vehicle, and this demanded an implementation in the control system of a whole set of fire and explosion safety measures.

In 1984-1988, Khartron worked simultaneously on two projects of large scale and utmost responsibility: the development of guidance systems for the SS-18 missile and for the delivery vehicle Energia. This demanded from the leadership and the specialists their maximum efforts. Work went on around the clock, including weekends and holidays; people often spent the night on their workplaces. Their greatest reward for these efforts were two successful launches of Energia on February 22, 1986, and on November 15, 1988, and the successful completion of field tests of the SS-18 missile and its placement on active duty.

A large amount of work was also carried out in order to build onboard computer complexes for the guidance systems of various space modules. A computer complex with multi-level majority, which remained in operation even after 10 to 20 local malfunctions, was built for the modules Kvant, Kvant-2, Kristall, Priroda, and Spektr, which worked with the station Mir. Its failure-free operation on the orbit for more than 10 years has proved the validity of technical decisions taken by Khartron specialists.

In the late 1980s two new onboard computer complexes were built for a new generation of spacecraft guidance systems. These complexes consumed much less energy than their predecessors. Successful launches of various spacecraft using these complexes have demonstrated that Khartron is capable of equipping spacecraft with reliable onboard computers.


Malinovsky's closing remark: A.I. Krivonosov, the chief designer of a unique radiation-resistant onboard computer complex, has received the Lenin Award for its construction.

site last updated 16 December 2002 by Slava Gerovitch