Interview with Georgii Priss
Moscow, May 23, 2002
In 1948 Georgii Priss graduated from the Moscow Aviation Institute and
joined the Scientific Research Institute No. 885 (NII-885) of the
Ministry of Communications Equipment Industry, led by the Chief Designer
of control systems for Soviet rocketry Nikolai Pilyugin. In 1963 NII-885
was transformed into the Scientific Research Institute of Automatics and
Instrument-Making (NII AP), and in 1965 it was subordinated to the
Ministry of General Machine-Building. In 1978, the Research-and- Production
Association of Automatics and Instrument-Making (NPO
AP) was created on the basis of the Institute, and in 1994 it was
subordinated to the Russian Space Agency. Currently this institution is
called the Pilyugin Research-and-Production
Center of Automatics and Instrument-Making (NPTs AP). Georgii Priss worked on gyroscopic
equipment for the first Soviet rockets, and he was the principal
integration engineer during the design of control systems for the R-5 and
rockets. In 1956 he became Pilyugin's deputy in charge of equipment and
test-and-launch complex. Priss was the principal developer of control systems
for the N-1 and the Buran projects. Currently he is the head of
Integration Department at NPTs AP.
This interview was conducted and translated from the Russian by Slava
Gerovitch: When did the idea of using onboard computers in
spacecraft control systems first arise? Who suggested it first? What
reaction did it provoke? Was it implemented right away?
Priss: By the time this idea emerged, the use of computers had already
been widespread. There already existed ground computing systems; some information
about the construction of specialized computers for guidance (not just
spacecraft guidance) had appeared. Generally speaking, this idea was in
the air. Computers had already spread quite widely. It was abundantly clear,
especially for the main designer of control systems for spacecraft
Alekseevich Pilyugin, that computers could be used for solving problems
of guidance and that they had many advantages over analog systems, which
had been used before. It is hard to tell, to whom the idea of using computers for these
problems came first. This idea was conditioned by the achievements of
engineering at that time, including the achievements in computing. At
the initial stage of the development of computers, it was simply
impossible to use them because of the large dimensions and huge energy
consumption, by the mid-1960s technology advanced so much - both in
terms of basic elements and design techniques - that computers became
quite acceptable by these external parameters.
The first onboard computer was installed on a space vehicle sent on
Mars. It was part of the control system for spacecraft intended for flight
toward Mars in the mid-1960s. Pilyugin decided to use a computer
code-named the Argon-11, which had been developed under the chief
designer Krutovskikh. A Moscow organization [NIEM, later NICEVT]
was designing computers,
which by their external parameters were quite suitable for use as part
of onboard equipment in spacecraft. And they modified their Argon
computer to adapt it to the kind of problems in which Pilyugin was
interested, and they code-named this new computer the Argon-11. These
problems were by and large problems of guidance. This was the first example.
After that, Pilyugin acted in his specific manner, in his
"technical spirit." He had been designing control systems since 1946,
and he always adhered to idea of building an autonomous control system
that would contain all the elements necessary to fulfill all functions
of a control system. This was not an unfounded claim; this was a clear
idea. If the development of all elements of a control system is
concentrated in the hands of one chief designer, then the control system
can truly be optimized. It makes it possible to allocate functions among
various parts of the system in the most expedient way in terms of weight, dimensions,
energy consumption, and functional decision-making. With this approach, all
main, as well as auxiliary, parts of the control system are being developed in one organization.
The application of this approach to the introduction of computers was
not the first step that Pilyugin made in the development of an
autonomous control system. Shortly before that, about five years
earlier, he performed a similar manipulation with a major unit included in
the nucleus of a control system - with the gyroscopic unit. Until the end of
the 1950s, inertial gyroscopic devices had not been developed in
Pilyugin's firm. There were organizations specializing in this; in particular, the organization
under the Chief Designer Kuznetsov worked on rocket engineering. He developed gyroscopic devices of
various types, including gyroscopic platforms. On one of the rockets developed in second half
of the 1950s, Pilyugin included in the structure of the control system a gyroscopic platform
developed in Leningrad by the Chief Designer Aref'ev. Having acquired
expertise, having obtained results of some tests of this platform on
location, Pilyugin himself started the development of gyroscopic platforms.
He used the same approach during the introduction of computers into the structure
of a control system. The first experiment that I mentioned - the experiment with
the Argon - resulted in Pilyugin's decision to start the development and
manufacturing of his own computer systems.
For the second phase of the development of the lunar complex N1-L3, Pilyugin
decided to design his own onboard computer. At the first phase, the
control system included some gyroscopic devices of the Chief Designer
Kuznetsov and some analog systems. At the second phase, a totally new control system
was created. This new design was implemented in the fourth (last) launch in
1972. The new control system included a gyroscopic platform and a computing system,
both designed by Pilyugin. This computer, called the S-530, was based on
the Tropa elements. It was intended for calculating all control tasks:
guidance, control of the operating logic of the control system's own equipment,
and control of the engines and of all other systems in the N1 rocket. There
were plans to use the same machine for the control system of the LOK (the lunar orbital ship) and
the LK (the lunar ship). Unfortunately, these plans did not come to
fruition. The fourth launch did not result in the operation of the LOK
or the LK, and therefore there were no experimental results on them. After that, all
control systems developed by Pilyugin included computing systems of his own
After that came the computer series we named the Bisser: the
Bisser-2, the Bisser-3, the Bisser-4, and the Bisser-6. The Bisser-6
represents today's technological level. Of course, these machines
developed and improved over time. In particular, the scale of circuit
integration increased: first medium-scale integration, then large-scale integration,
and now solid-state technology of very large scale integration. This
gave us an opportunity to increase the computing resources of the machine,
to enhance its memory, to raise its speed.
All these systems were based on the same design principle. Higher reliability was
required for the control system in general, and for the computing system
in particular. Therefore all these systems were designed with
redundancy. They could withstand damage in any single component. They
had radial interfaces with various exchange devices, such as gauge converters
and operating component converters.
Along with the introduction of onboard computers, computer equipment was
being installed at ground testing and launch facilities. Here the same
approach was used. While during the development of the first rockets, for example,
the N1, the ground facilities used industrial production computers, such as
SM-2 (developed at Severodonetsk), later on they switched to ground
models of the same onboard computers. Those ground models also had
higher reliability. The use of the same type of computers made it easier
to establish computer-to-computer communication between the ground and
the board, and this approach is still used today. Since the structure of
the control system for various space vehicles (with the changes in
rocket stages and cargo weights) has evolved significantly during these
forty years, a whole multi-computer system is now created, which
includes a ground machine and several onboard computers.
Onboard machines may have different purposes, and sometimes this results in
the development of specialized computers. For example, some onboard
computers provided communication between the central computing system with
various onboard systems, in particular, with radio systems or with the system of information and
controls display. Such specialized computers could be of different
types, they could have different cycles and interface types; nevertheless,
with the help of appropriate adapters and coordination devices,
integrated systems were successfully created. This principle was
implemented not only in Pilyugin's projects. The long-term space station
Mir also included a multi-computer control complex developed by
specialized organizations, in particular, by the Zelenograd Science
Center. It is the same today with the International Space Station:
diverse types of computers are included in an integrated computing system.
Gerovitch: Researchers from NICEVT,
who developed the Argon-11, say that this computer was installed on
board the Zond spacecraft that circled the Moon.
Priss: The Zond is a name for the L-1, which is also our project,
but this happened after the flight toward Mars. The Argon-11 was used in
other projects too. Speaking of priority, the very first use of this
computer was on the spacecraft sent to Mars. The L-1 was launched with
the Proton rocket; this project preceded an expedition to the Moon.
There was one successful launch of the L-1, which returned to the Earth
and landed with escape velocity. If this project were to continue, this
computer would have been replaced with the S-530 machine too, but this
did not take place.
Gerovitch: In the initial period, when digital computers were
introduced, what was seen as their advantages in comparison to analog devices?
And their deficiencies? Was it obvious that a transition to this new
technology was needed?
Priss: At that stage this was not obvious. First, the basic elements at that
time were not sufficiently reliable. Failures were numerous, and
therefore a decision to launch could be made only when redundant devices
were installed, and there was hope that back-up systems would ensure
operation during the flight. During preliminary tests all back-up
systems, including the computing system, were being checked, and, as a result,
a very large number of elements was tested, and failures occurred more often.
For this reason, preparations for the fourth N-1 launch (when an onboard
computer was used) proceeded with great difficulty. Various computer
elements failed all the time, repairs were being made, and every time it was necessary to
justify a move to the next set of tests.
Second, digital computers at that time did not have any advantageous external
operational characteristics. That is, they were not much lighter or more
energy-efficient than analog systems, and in this sense there were no advantages.
One had to learn how to program them, how to test algorithms, how to
test software. All this involved great difficulties, and we placed our hopes on
future developments. At that time, it was already clear that this
technology had good prospects, since the development of new basic elements
was under way. It was clear that computers could solve much more
problems than they did at the initial stage. Today computers solve all
the problems of the logic of control, problems of control of all other systems,
not to mention new, advanced guidance systems, which would have been very difficult to
achieve with analog devices. Innumerable changes in the shooting angle,
in the flight direction, in the trajectory, transitions from one trajectory
to another - all this could be solved with analog methods, but it would
have been much more difficult. Not to mention the speed of calculation,
which is very important for logical tasks. It is less important for
guidance tasks; in the latter case, all processes run more slowly, than, say,
the processes of starting-up and adjusting the engines. Initially all these
problems were solved with analog methods. As computers improved, these
tasks were shifted on to them, and thus the functions of the control
system were substantially expanded. The use of computers made it
possible to eliminate entire types of equipment and subsystems. For example, today
a computer-based gyroscopic system, incorporated into the control system,
fulfills the task of the initial azimuth aiming of a rocket. All the first rockets
of the 1940s, 50s, and early 60s were aimed with the help of an external geodetic system, which somehow
had to agree with onboard gyroscopic devices. One had to perform a geodetic
locality orientation, one had to install special geodetic devices on the ground,
and then, with the help of optical communication devices, one could turn
and aim a rocket. The launch installation had to provide means for
turning the entire rocket. Later the whole turning operation was transferred from the
rocket itself to its gyroscopic system. And when a computer complex was
added to the gyroscopic system, the entire system was greatly simplified. Onboard
pulse generators, which earlier had been used for temporal tasks, were
eliminated; current distributors, which unfolded a "cyclogram,"
were also eliminated - all this is now done by a computer complex. As a matter of fact, the computer complex and
the gyroscopic system are the only essential components of the control
system; everything else are just various converters and capacity amplifiers, which
control operating components, rocket automatics, engine automatics, and
power source, and that's it. Actual control problems, which earlier had
been solved by complex devices, are now solved by a computer. Today ground
computers prepare the flight task and recalculate it on the fly if necessary. As a matter of fact, all serious functions of
the control system are now performed by computers.
Gerovitch: You mentioned that the first computer made at
Pilyugin's firm, was built on the Tropa elements, which were not very reliable. When
did the transition to integrated circuits occur? Why did it happen?
Priss: The S-530 computer was developed in the late 1960s, and it
was used on a spacecraft in 1972. Subsequent machines in the 1970s were
based on integrated circuits of various types; the first had
medium-scale integration. Here again Pilyugin chose an original approach.
At that time, there existed different possibilities for development. In
our branch of industry, a new, so-called "open-frame" technology
was available: a designer could built the required circuits with
open-frame elements - tiny diodes and triodes - and could in practice, not just on
paper, implement something similar to medium-scale integration elements.
This technology was being used, but not at Pilyugin's firm. He chose an
alternative method: he let contracts to various specialized
organizations of the Ministry of Electronic Industry. According to his
specifications, large-scale integration elements were developed.
Pilyugin's firm received finished, well-tested elements, and then
assembled the required structures out of those elements. Such was our
approach in the 1970s, and it was used not only at Pilyugin's firm. In
the late 70s the same approach was used by another firm engaged in the
construction of control systems, the Khar'kov Institute [Khartron].
All other design organizations that worked on various elements of a control system
also introduced one technology [of integrated circuits] or another. The
"scattering" technology was widely used with good results at
the Research-and-Production Institute of Measuring Technology, which
built telemetry systems, gauge equipment, transformer equipment, and so
on. I believe they still use this technology. Our Bisser-6 is built on
large-scale integration circuits developed at Minsk or Zelenograd firms.
Gerovitch: The Americans chose integrated circuits as basic elements for
the Apollo Guidance Computer in the early
1960s. Was there any study of the American experience? Was it taken into
account? Did it have any impact on technical decision-making?
Priss: I am not aware of that. In 1960s NICEVT was engaged in
this more deeply than we were, and they possibly knew something. In the
past several decades, this information has widely spread. Studies [of
foreign equipment] and comparisons with basic elements and capacities of our electronic
technology go on all the time. For a long time, the military system of
quality testing blocked applications of these [foreign] types of systems or elements.
Until the last decade, everything [in the space program] had to pass
quality checks by military organizations, and one of the requirements
for control systems was the use of domestically manufactured basic elements.
In recent years this rule has become non-obligatory. If such [foreign] technology
is used, this requires detailed knowledge and understanding of what is
being done abroad, and this also requires the creation of domestic
analogs to foreign models. To create an analog takes a lot of time. To repeat
always means to lag behind.
Gerovitch: Was there any discussion of the American design of a control system for
Priss: I do not recall seeing such materials or publications; I
do not think that we had detailed knowledge and understanding of
hardware implementation of the Apollo control system. There was some information
available about general design solutions and trajectory formation for
the Apollo, but this lay outside of the realm of the control system.
This information could be of interest only to the lead organization,
which was selecting trajectories and strategies for space flight. Despite
the substantial openness of the Americans and the availability of
endless material on the Shuttle (there was less available on the
Apollo), there were almost no publications that would specify hardware
design. One could find some general characteristics of the equipment, for example,
of a gyroscopic platform or of a computer (speed, memory, and so on), but
more substantive information was absent. Perhaps, this information was
available somewhere, but it did not reach us, the developers.
Gerovitch: Have there been any attempts to compare American onboard
computers with Soviet ones in terms of weight, speed and so on?
Priss: I know that in the early 1980s there were attempts to compare
the parameters of systems designed for the Buran and for the Shuttle. And I
must say that, based on external parameters, we did not lag behind. Our machine on
the Buran was the Bisser-4. In terms of computer performance per se, the
parameters of our machine were close to theirs; perhaps, we even had a
lead. As for the functional operation, here you have to take into
account that the overall structure of our system was different. Speaking
of computers, the overall picture was as follows: there were four machines on
the Shuttle; they worked in the regular mode on all stages while a
spacecraft was reaching an orbit, and they were supplemented with the fifth machine.
This fifth machine was of the same type as the other four, but it had
different software, different "mathematics." It was used as
back-up mathematics in emergency. According the American plan, this
back-up mathematics was to be developed by another team, not by those who
did mathematics for first four regular machines. The idea was obvious.
In the American case, a switch to the back-up system was to be carried out by
an astronaut. He had to realize that the first system was not working
satisfactorily and to switch manually to the second system. We did not
adopt a similar structure for two reasons. There was no other organization
that could develop the second mathematics. Even if such an organization
could be found, it was still necessary to test and debug their mathematics. Our
testing program included an extensive cycle of ground testing and later
in-flight testing. The second mathematics would have required additional
spending and cause time delays, and we could not afford this.
All these issues were widely debated by technical specialists engaged in
the development of the Buran. There were many organizations involved. The
lead aviation firm that built the Buran glider and was responsible for landing
issues very actively demanded that this question be considered. But eventually we
managed to prove the reliability of our regular system. Together with
the Rocket-and-Space Corporation Energia, we managed to demonstrate that we
foresaw a large number of potential emergencies, and for all these
potential emergencies we developed automatic modes of coping with them and
rescuing the crew.
For example, the mode of "restoration of control" has been introduced
on the Buran for the first time. Let's say, for some unclear reason the control system
breaks down on the orbit, all four machines break down, orientation is lost, the
spacecraft begins to make strange and unpredictable maneuvers - for example,
because of a fault in the power supply. If power is not restored, even
the Americans with their fifth machine could do nothing. If power is restored,
however, then a special mode would be switched on, which would restore orientation,
tell you where you are, restore all processes, and make it possible to rescue
the crew and to return them to the Earth.
Nevertheless, the idea of an additional, back-up system was discussed all time, and
as a result, it was implemented - not in hardware, but mechanically (a hand controller
and so forth) on the model 002 intended for horizontal
flight tests. This model of the Buran was tested in the Moscow region with numerous
lift-offs and landings. On this model, a manual landing control mechanism was
implemented, but it was never used, since the automatics worked without failures.
Comparisons occurred all the time. Not only computer facilities were
compared, but also gyroscopic systems. We had the same amount of the information
about their gyroscopic devices. Only external parameters of the
gyroscopic platform were known, not the internal ones. Here we did not
fall behind either. And if entire systems were compared - the control
system on the Buran vs. the avionics system on the Shuttle - a
competent, correct comparison was impossible, because there was no information anywhere on
the specific tasks carried out by the avionics system. Based on its
approximate composition and on information from some marginal sources,
one could conclude that their avionics system did not carry out all the
tasks assigned to our control system. Certainly, the avionics carried
out guidance and controlled both automatic and manual modes, but that
was all. What else could it do, what equipment was included in the
avionics system to carry out other tasks - all this was not at all clear.
The matter is that except for the gyroscopic platform and the computer,
whose functions were completely clear, all the other equipment [in the
Buran control system] was developed as a complex, that is, it not only
controlled operating components, but also carried out other tasks. A
computer route - stretching from the cabin, where the computing system
was set up, to the exchange devices, which were installed in the tail compartments of
the Buran - transmitted not only information necessary for the control
of aerodynamic surfaces on landing, but also data required for the
control of engines, for the control of small-thrust nozzles, and so on. Therefore,
it would be incorrect to compare our route with the route in the Shuttle
if it did not serve the same function.
Gerovitch: How was the problem of division of functions between
human and machine resolved at different stages? How did the functions of onboard
Priss: If we talk about the first machines, in the case of the
Mars probe, it was a fully automatic spacecraft. The N-1 carrier was
also automatic system; the orbital ships were supposed to have a pilot and
manual controls, but unfortunately, as I said, they did not get a chance
to be tested. The only case about which I can say anything is the Buran.
Everything that was done by our firm before or after the Buran are automatic systems. In
some projects carried out by
the Rocket-and-Space Corporation Energia, on orbital stations, some functions were
assigned to the crew. I do not know the details. I am not aware whether
any such functions related to guidance.
As for the Buran and the lunar ship, they had the so-called "manual
guidance contour." The implementation of such contours in the presence
of an onboard computer was limited to the following. On the Buran, the manual
guidance system, which included a steering wheel, hand controllers, and pedals
(like on the Shuttle), had two modes of operation: the landing mode
(with problems similar to aircraft landing) and the orbital control mode
for docking and undocking. There were different types of controls for these
tasks: the aviation controls were the steering wheel and the pedals,
while the orbit controls were the hand controllers in three dimensions. The information from these manual
controls through converters was entered in the computer. There were no
special operating components for manual control; they were the same
components that were used in the automatic mode. It would have been ridiculous to put additional
ailerons or vertical or horizontal rudders [for manual control].
The main question is this: what algorithms are used to process the information received from manual controls?
There are two possibilities here. The first is this: no function is assigned to the
computer, except for simple transmission, that is, whatever the pilot has
done is transmitted to operating components one-for-one. The second variant
is to limit his possibilities. Say, not to let him give a silly
instruction or an untimely instruction. The latter variant is in fact
chosen. There are some restrictions on the pilot's actions.
Next, the pilot should receive some information. During docking, he must
see a picture, he must be able to aim correctly. Here too there are
several possibilities. First, he can make observations through separate optical devices (for example, on
the Buran, there was a pilot's sight and some other optics through which
he could look independently from the machine). Second, he should
receive information about the condition of onboard equipment, at landing
you must show him the landing field, he must have arrow indicators, as in
an automobile or on an aircraft. The latter task [of information
display] was entrusted to the computing machine, since this information
came from inertial system gauges, or from systems of air-velocity
parameters, or from radio systems, and it fed into the machine. The
machine needed this information for automatic control. But besides this
use of information in the machine, it was also displayed for the pilot
The Americans assigned a greater role to the pilot than we did, and
the pilot had more opportunities to see a situation. In the Shuttle, for example,
he even had some indicator panels above his head. In our case, the situation
was a bit different. It was decided in the beginning that we would
design a shuttle that would be able to work both in the automatic and in
the manual mode. Therefore, everything had to be automated for the automatic
mode. And so it was done, for example, automatic landing was
implemented. Then, when this implementation was combined with manual
control, naturally, an idea arose: here everything is already in place,
so the pilot's role may be limited. Indeed, the machine thinks faster,
it executes commands and evaluates the situation faster. The Americans
faced a different situation, and for this reason they assigned wider functions to the pilot.
On a lunar complex we had manual control, because landing on the Moon
was to be performed manually. There were special controls made,
information display units, and so on. All this was done through the machine,
in the same way.
Gerovitch: Was the control system for the lunar ship completed?
Priss: It was completed; it passed almost the entire cycle of
testing on the ground. It was ready for operation.
Gerovitch: Let's come back to the Buran. If the computer
determined that the pilot was making a potentially dangerous move, what
happened in this case? Would it cancel this action?
Priss: No, the computer simply limited the pilot.
Gerovitch: For example, the pilot could not make a turn by more than
a certain number of degrees, right?
Priss: He could not make it greater than the number that the machine
Gerovitch: That is, the computer physically limited possible changes?
Priss: Yes, it did.
Gerovitch: Was there anything the pilot could do to override it?
Priss: He could not pass the preset limits. He could operate only
within the limits set by the machine, or, to be more exact, by the developer of
the algorithm. He could do another thing. He could manually switch to a
different control mode. All the modes were automated and had a specific algorithm
(that is, a program). If he had serious reasons, he could, for example,
cancel docking. Say, he is on a shuttle which is docking with a station in
the active mode, and he receives information - either from the station, or from
the ground - that for some reason the docking cannot be performed, while
the docking has already began. He can manually cancel this mode and
switch to another. He can choose a control mode. This switch could be
performed automatically by criteria that the machine understands, or by
command from the Earth, or by the cosmonaut.
Gerovitch: That is, he could only switch from one mode to
another, but could not disconnect the computer completely?
Priss: In principle he could disconnect it, but this did not make
Gerovitch: Who was doing programming for the onboard machine on
Priss: This is a very broad issue. If we talk about small projects, such as
the Mars or the N-1 (in terms of computing and programming tasks, those automatic projects from
today's perspective were not so big), then the development of mathematics was
done as follows. There are three circles of programs for the machine. The
first circle is a set of tools for the machine itself. The machine must have
an operating system, which directs the computing process: how to address various
types of memory and how to receive and send out external information;
there are also channel programs, input-output programs, and so on. All this mathematics
does not depend on the task carried out by the machine. It must control
the execution of any task assigned to the machine. A special group of programmers is
assigned to create this set of tools. They are "pure" programmers who
must know the computer, its system of the instructions, and the chosen
interfaces very well. One must add to this set also the algorithms of
flight mission input, of flight mission control, and of dialogue with other machines (if
this is multi-machine system, then some computers must be active, and
some passive, and so on). This set of programs is specific for each computer. If I
switch this machine to a different set of tasks, this set of programs will
remain the same.
The second circle of tasks are guidance tasks. This includes the
processing of information from various sources (inertial systems, optical systems,
and radio systems). Then the computer solves the guidance problem,
taking into account various dynamic characteristics of the object of
control: inertial and weight characteristics of the spacecraft, the characteristics of
various operating components, dynamics requirements, and limitations
imposed by the rocket design (for example, there are limitations on turn
angles and on rotation speeds). The programs that we include under the
guidance rubric, as a rule, are developed by programmers from the main
organization that designs the control system. If we design the control system,
then these are our programmers.
Gerovitch: Are these programmers trained as engineers? Do they understand
the logic of the control system well?
Priss: Certainly. They design it! They design guidance
algorithms. For example, one can direct a flight along a rigid trajectory,
in which case any deviation from this trajectory is detected by sensors, and then the
spacecraft must return to the straight path that you have laid out beforehand.
This is yesterday's technology; nobody does this today. Today science
has developed the technique of terminal
control: it does not matter how I fly; what is important is that I
arrive in the given final destination with the given speed, angular parameters,
and so on. It means that I don't have to force the product, to twist it
this way and that; I save fuel and power; I don't have to make an extra
durable spacecraft that would resisted the wind. If the wind sweeps it
away, let it do it; you can correct for this later. This is the meaning
Programming is done by people who know, understand, and can do all of
this. Besides, they know the computer and its operating system; they know
the capacities of the machine. They try to solve problems without
spending much memory or computer time, that is, they try to make an
optimal use of its resources. As initial data, they use specific
trajectory requirements set by the developers.
There are some exceptions to this approach. For example, V.A.
Trapeznikov's institute, that is, the Institute of Automation and Remote
Control [currently the Institute of Control Problems], develops for the
large rocket complexes algorithms of calculation of complex dynamic processes,
in particular, algorithms related to the regulation of component ratio
in the fuel for rocket engines. This line of research was started by the
academician B.N. Petrov. They begin the development of this type of
algorithms and then transfer their development to our specialists, who
link these algorithms with their own algorithms that also relate to
motion. For example, if the engine is adjusted, then the velocities also
change, and these algorithms must be somehow coordinated.
The third group of programmers resolves issues related to the logic of
control of all other processes, other onboard systems. Such issues also
have two parts. Say, a developer of the control system formulates an algorithm of engine
control and requirements for separation. The stages must be separated
under specific strength conditions and so forth. Here contact with the second group of programmers is
needed. For example, it is necessary to turn off the engine when certain
velocity is reached. Velocity is measured by specialists in dynamics, but they do not
know how to turn off the engine. This is not a simple instruction but a whole
cyclogram. These specialists only issue a command to turn off the
engine, while the entire cyclogram - all subsequent operations with the engine, with
separation, and so on - is done by "complex" programmers, who know
little about motion and dynamics, but who understand the logic of
operation of all system.
It was precisely at this stage that the developers of the Buran faced
incredible problems caused by the very volume of the task. There were
the total of 52 onboard systems that were subject to automatic control
by a computing system. Some of them were controlled by the control system, and
some were not. Take, for example, the telemetry system. There is a chief
designer of this system, who designs this equipment and knows how it should work.
The telemetry must be turned on and off, its mode may have to be
changed, and so on. Only he knows the algorithm of working with this system,
but it is the computer that will actually be operating it. This means
that there must be a program for the telemetry system. To find a place for this program and to agree upon
its interaction with other programs is a task of "complex" programmers working for us.
Then a question arises: who will write this specific program? On a simpler
type of spacecraft when we faced similar problems but they were not so
numerous, the following method was used. The developer of this system draws
the cyclogram in a usual way, without translating it into a mathematical program, and
then our "complex" programmers translate it into a program. This way there always were
some discrepancies, misunderstanding, and errors, and several iterations
were needed to correct and debug it. It was not feasible to use the same
method on the Buran; in this case, the design stage would have taken 20 more years.
For this reason, high-level programming languages were created that enabled the developer of
a system to write up an algorithm without knowing any characteristics of the
computer, its system of instructions, or any other internal requirements of the machine.
He would write an algorithm in a simple, clear language, and then a programmer on the basis of this initial material
would write a program for the machine. During the design of the Buran,
the translation of this algorithm into a program was done mainly by hand with
the help of some semi-automatic tools. Today new systems exist that can
process this information and produce a complete program as a result.
After that, this program, of course, has to be tested: first on
autonomous simulators, and then on complex simulators. I have included in my
article a list of organizations involved in this project as part of the
Buran program [G.M. Priss, "Nekotorye aspekty razrabotki sistemy
upravleniia 'Burana'," Aviakosmicheskaia tekhnika i tekhnologiia,
no. 3 (1999): 35-42.].
Gerovitch: Did the Institute of Applied Mathematics take part in
Priss: Yes, they participated most actively. The academician A.N.
Tikhonov supervised this project; M.R. Shura-Bura was among his top
aides. They worked together with us, since our specialists knew the
specific characteristics of the computers. They created the PROL language
for programming this type of tasks - not guidance problems, but logical
Gerovitch: Could you tell more about the Bisser computers?
Priss: The Bisser-1 did not develop beyond the design phase. The
Bisser-2 was designed in the late 1970s-early 80s, and until recently it
was installed on Zenith-2 rockets. This machine was used quite widely
and was installed on many different models. The development of the
Bisser-3 went in parallel with the work on the Bisser-4 for the Buran.
These two machines were principally different. The Bisser-3 was also widely
used. Today it is installed on the Zenith-3, on the acceleration module
of the Sea Launch; it flew on the acceleration module of the of the Frigate
(there have been four joint launches with the French).
The Bisser-4 stayed apart from these models; it was an original machine.
It was used only on the Buran. Its main feature was that each channel
was structurally autonomous, that is, each channel was a separate machine. It
was possible to combine as many of them as necessary. There were four machines in one complex and four machines in the other complex, and
the majorization of the output was carried out by a special logic
switchboard outside of these machines.
Gerovitch: Would it have been possible to install five machines?
Priss: Yes, it would have. The only thing that would have to be
changed is the logic switchboard so that it could process information from five sources. It
would have been also possible to install only three machines. Our choice
of this logic was influenced by the American structure: they have a fifth machine, and
it works according to its own program. But since it uses a different program,
it is impossible to apply the majority principle. This principle
requires a comparison of similar information from all sources and
suggests using those outputs that are identical. For example, out of three machines two
results must be identical; if one machine deviates, I simply stop paying
any attention to it and take information from the other two. Out of four machines three
results must be identical. It is possible to build more complex logic: to compare
pair by pair and so forth. But if the fifth machine has its own program,
it cannot be part of this process. Before the final output is given, all
the computers of the Bisser-4 complex exchange information among themselves.
This way the reliability of such a system sharply increases.
In all current models the Bisser-3 is used. The next step is the Bisser-6 machine
on integrated circuits of higher integration (newly developed by organizations
in Minsk and Zelenograd). This computer has improved communication with external
users, a higher speed, and a different type of memory. So far this machine
has been used in ground testing complexes. It is hardware- and
software-compatible with the Bisser-3 (with small corrections). When we
decide that it is completely tested, it can be installed on all models where
currently the Bisser-3 is used. The Bisser-6 is cheaper, its elements
are smaller, it is lighter and more power-efficient. It is our next step.
Gerovitch: Does the Bisser-6 complex operate on the same principle
as the Bisser-3, that is, its computers are integrated, rather than
Priss: Yes, that's right.
Gerovitch: Let's go back to the Bisser-4. Say, one of four machines gives
a result that differs from the others. Would this machine be turned off
completely, or only its result during this one cycle would be discarded?
Priss: No, its result would be discarded only during this cycle.
This could be a sporadic failure, and it could work normally in the
Gerovitch: Would this machine be included in further operation on
a par with the others?
Priss: Yes, certainly.
Gerovitch: Were there any computer malfunctions during the Buran
Priss: On the Buran there was not a single malfunction - not only in the computer, but in
the entire control system. The entire preparation cycle was repeated twice. The first
launch of the rocket carrier Energia with the Buran was scheduled for
November 30, 1988. But they called it off right on the launching site. The system
did not take off because the mechanism of retraction of targeting optical devices on the carrier
(I already talked about it) did not work.
Today no optical systems are used during launches. Our gyroscopic platforms have a
gyro-compass mode, that is, the platform itself can determine the
cardinal points; there is no need for geodesic or optical devices. Wherever the platform
is, it will determine its location and direction of movement. The Americans
did not have that, and they had to aim precisely. The matter is that the
Americans do not have a separate rocket. They have solid-fuel
accelerator engines and a tank that works with the Shuttle engine. Therefore,
a control system - the "brain" - is installed only on the
Shuttle. They had three gyroscopic platforms, and it was necessary to
aim them. For this purpose they used a ground optical system. But they
were able to put their platform on the left board of the cabin and somehow managed
to establish an optical connection from the Earth to aim correctly.
We have not been able to place our gyroscopic devices on the Buran in a
similar way. This happened not because our platform is bigger; in fact,
it is rather smaller than the American one. The matter is that the requirements
for automatic operations - including such operations on the orbit as
docking, determining the location, and so on - resulted in expanding the structure of
the control system with a whole complex of automatic optical devices:
stellar-solar gauges, navigation antennas, and so forth. It was
necessary to be able to adjust their position with relation to the platform. All
our gyroscopic devices were installed not in the front, but behind the cabin, in
the cargo compartment. Three platforms (a triple-redundancy system) and all optical
devices were put on a very powerful adjusting plate. But the cargo compartment is closed!
It opens only on the orbit. And they were not able to make a slit to reach these devices.
At that time, we did not have platforms with the gyro-compass mode. We
needed an optical orientation to set the initial azimuth, but this could
not be done. Therefore, we had to do optical orientation for the platform
that stood on the rocket.
Our Energia rocket had an independent control system (which the Americans
did not have), and therefore the Energia could be launched without the
Buran. Its gyroscopic system had to be aimed correctly. A ground optical station
aimed it with the help of special optical devices. It was necessary to transfer two beams to each platform, and
there were three platforms in total. On the N-1 we solved the same
problem. A top optical aiming device is set up, which is needed only on the
ground. It is not needed in flight, since you have already aimed and
took off. On the N-1 we simply dropped this device; it fell on the
ground and shattered. It could be used only once. On the Energia we
decided this was a waste, and we looked for a way to preserve these
devices. On the N-1 this would not have been possible: it was too high,
the service trusses moved away, and there was nothing that could pick up
those devices. And now such an opportunity arose. The Energia was much lower,
smaller than the N-1. There was a special truss construction made that
supported those three devices. It was joined to the rocket, and at a
launch it was to be separated automatically (special pyrotechnic locks
were made) and moved away from the rocket.
On the first launch on November 30, 1988, this system did not work. More
precisely, the separation took place, but there was a tilt, and a
confirmation that it worked did not come through. The launch was
aborted. But up to that moment all preparations on board passed without
a single flaw. The fuel tanks were emptied, and another attempt was
scheduled in two weeks, for December 15. We have repeated the entire
routine. This time this thing worked and moved away, we reached the orbit, made two
turn circuits, and then the process of deceleration and descent began.
At this stage, there were other difficulties. We landed in the automatic
mode. There was a side wind of 17 meters per second, but we landed within three meters
of the center of the landing strip. Not a single flaw there was. Neither at
the take-off, nor during the ascent, nor during the flight.
Gerovitch: What was Sergei
Korolev's opinion on the prospects of using onboard computers? Some say that he looked for contacts with various organizations, in particular, with
the design bureau of Philip Staros and Joseph Berg in Leningrad, where
mini-computers were being developed in the early
1960s. Others contend that he was skeptical about this. Do you know what
his opinion was? To what extent could this opinion influence Pilyugin's
Priss: Pilyugin always was on very terms with [Sergei
Pavlovich] Korolev. They were friends,
and therefore Pilyugin always listened to Sergei Pavlovich's opinion.
They never disagreed on principal issues. They had some disagreements on
specific questions. They often had quite harsh and vigorous disputes. But
Korolev died in 1966. It was just the beginning. I was pretty close to
the these circles, and I never heard of Sergei Pavlovich's negative
attitude toward computing.
I am not aware of the contacts that you mentioned. I can only make
the following assumption. At that time in Sergei Pavlovich's organization
there already formed a large division under the direction of Boris
Evseevich Chertok. They too were engaged in designing control systems.
This happened because when they began the development of manned
spacecraft (on satellites, it is a different matter, since satellites are
quite passive from the point of view of
control), Sergei Pavlovich offered Nikolai Alekseevich to make a control
system for them. Before that, nobody was making control systems. True,
in the late
1950s there already existed a firm in Khar'kov which was doing for the
chief designer Mikhail Yangel the same thing as we did. In the same period,
a special design bureau under the direction of Nikolai Semikhatov
[currently the Research-and-Production Association Avtomatika] was set
up in Sverdlovsk; they began doing the same for navy complexes. And the
directors of both firms were former employees of our organization.
The time when Sergei Pavlovich offered Nikolai Alekseevich to
participate in this project was a very difficult period for us in terms
of work load and also personal relations. Gagarin flew in 1961. His
spacecraft was a primitive device. He landed on a parachute; the
spacecraft had almost nothing to do. Korolev envisioned a whole series
of advanced piloted spacecraft, and later this was indeed implemented.
At that very moment [the chief designer] Vladimir Chelomey began working
on spacecraft, and Pilyugin was assigned some projects for him. Thus, we
did work for Korolev and for Yangel, and then Chelomey' projects were
added. Pilyugin realized that he could not carry out all these projects
at once, and he refused Korolev's offer.
Sergei Pavlovich began working on this problem in his own
organization. Boris Chertok, Boris Raushenbakh, and others were
involved. Their approach had its own specificity. Apparently, they coped
well, and this division still exists and solves these problems with good results, which are
in no way inferior to what we could do. The difference in approach is
another matter. We work by the method I described earlier - we
concentrate everything under one roof - while they are engaged, as a matter of fact, in compilation. They buy
a machine, they buy gyroscopic devices, they buy optical equipment, and
so on. We try to do everything ourselves, except for optical devices.
Apparently they realized, just as we did, that it was necessity to use computer
technology. I never heard anyone, including Sergei Pavlovich, speaking
against it. He was not in this sense conservative, and I can hardly believe
that he could take a negative attitude.
Gerovitch: Who designed the Mars spacecraft on which the Argon-11 was
Priss: Sergei Pavlovich.
Gerovitch: This means that this installation must have had his
approval. The decision to install an onboard computer could not have
escaped his attention, true?
Priss: Both he and Chertok understood all these problems perfectly
well. Later on Korolev transferred all automatic spacecraft projects -
the Moon, the Mars, and the Venus - to the chief designer Georgii
Babakin. Babakin too was a very progressive designer, and for him there
was no question [whether to use computer technology]. The first
successes of the lunar program - landing on the Moon and everything else -
were achieved with Babakin's spacecraft. Currently Babakin's Phobos
project continues, but it is not very successful. Now they are planning
the Mars-express project. It is difficult to imagine now that someone
could have objected [to the use of computer technology].
Gerovitch: By the mid-1960s, analog technology was improved to a
certain level of reliability, and new digital technology could raise doubts.
I often hear that Korolev insisted that it was necessary to rely on
well-tested technologies, to choose simple solutions without unnecessary
Priss: This principle always holds true. Everyone supports it. In this sense the West
is more conservative than Russian developers. We now often face this
problem. Today negotiations are going on with Boeing, which has created
the Sea Launch company, about further steps, in particular, to work not
just on sea launch, but also on ground launch. We put forward various
proposals, for example, to switch to the Bisser-6. They reply: "No, no
need for that. The old computer has already flown, and the new one has
not." We say: "It will be well tested by the deadline!" They reply:
"No, no need for that." I believe, they have the rule that all new
models must have no less than 70 % of old equipment. But even in the
remaining 30 % one could include a computer.
Gerovitch: Could you tell me about yourself: when did you join
Pilyugin's firm, what did you work on?
Priss: I joined the firm in January 1948. The firm was
organized by the well-known order of May 13, 1946, signed by Stalin. It was
a general order to start the development of rocket weaponry. It
contained specific assignments to various ministries. For example, it
would read "on the basis of such-and-such factory, create an
organization that will be doing this and that." A similar
assignment was given to the Ministry of Electrical Technology, in which
there was a factory that produced communications equipment: telephone sets, telephone
exchange switchboards, and so forth; it was located on Aviamotornaya. On the basis of
that factory, our organization was created. It had two assignments: the creation of
autonomous control systems and the creation of radio systems. Therefore, there were two
chief designers in our organization: N.A. Pilyugin and Mikhail Sergeevich Ryazansky. Pilyugin was the
chief designer of autonomous systems, and Ryazansky worked on radio
systems. All of them - Pilyugin, Korolev, [Valentin] Glushko - in 1945, after the Victory, were
sent to Germany, where they studied captured rocket technology. There were
doubts and debates in the Soviet Union: whom to assign the production of
this rocket technology? The Air Force refused; the Ministry of
Ammunition also refused. In the end Nikolai Dmitrievich Ustinov understood
the value of this technology - he was then the Minister of Defense
Industry - and he took up this job. Then Stalin's order appeared, and
all ministries received specific assignments.
The people who had worked at that factory now switched to rocket
engineering. They were telephony specialists evacuated from Leningrad, from
the Krasnaya Zarya factory. They were very competent in their work. They
were inventors, who in the early days of telephone engineering were engaged in
the construction of telephone systems - not only telephone sets, but also stations. The
captured German rocket technology was based on relay circuits. Analog
control devices were made with vacuum tubes. There were also some
gyroscopic devices. The Germans had only five devices in total.
Pilyugin, who had studied this technology in Germany, was appointed to supervise
these relay specialists. He had graduated from the Moscow Advanced
Engineering School (MVTU). In 1947, when we came, he had about 70
people. Back in 1946 he had just 30. In 1947 Pilyugin was a member of
the graduation examining board at the Moscow Aviation Institute. He
attended graduation project defenses and listened to these projects. He used
the following method: he talked to those students who came not to defend
their own project but to listen to another project defense. They were
about to defend their own projects, and they came just to listen. Based
on their graduation projects, Pilyugin selected the first group of six
students and hired them.
I was in the second group. I met Pilyugin at the end of December 1947, when
he attended project defenses of the first group. We still had about six
months to do our own projects. He told us: "Come to me, and do your
projects with me." We indeed came. He did tell us what we would be
working on - there was secrecy all over - he just said: "Here are such and such
research topics. If you want, I can hire you as technicians while you do
your projects." We did not know any details. We thought, why not? What's
the difference where to do our projects? So we agreed. We came in January, and
we defended in June-July 1948, and all stayed with him. There was also the third group, in 1950-51. Stalin's order was
all-inclusive: it had a provision for the organization of special
student training and student job placement in the centers of rocket
Pilyugin assigned topics by intuition, as I understand, and I got
integration. There were six of us, and the majority began working on
specific devices, while I was assigned to the integration laboratory. I
defended my project, and since then I have been working on integration.
The Soviet rocket industry had a unique organizational structure. If you
take aviation industry, you won't find there a "chief
designer" of the control system for a particular aircraft. There is
no such position, even though there are control systems, and they also
have gyroscopic devices and computing devices, and their tasks are as
complex as ours, and maybe even more. In aviation industry, the chief
aircraft designer - Aleksandr Yakovlev or Andrei Tupolev - used the
compilation method. They always had " equipment groups." Many
of our collegemates, who graduated the same year, before, or after, were
placed in so-called "equipment brigades." What they were doing was
to visit various aviation firms that produced autopilots, electric
transformers, radio equipment, and so on, and searched for the equipment
they needed. At best they could order equipment, but usually they had to
take whatever they were given, and then they compiled these pieces and created a control system.
By contrast, in rocket industry the chief designer of control systems
[Pilyugin] was appointed at the very beginning. Next to him was the
chief designer of gyroscopic devices, Viktor Ivanovich Kuznetsov. A
chief designer of radio systems also was appointed. The Council of Chief
Designers was created. It also included Sergei Pavlovich Korolev, the
engine designer Valentin Glushko, and the ground complex designer
Vladimir Barmin. That's six people in total, the entire Council. They resolved all
the technical questions.
What is integration? All these individual devices must be put together to make
a unified cyclogram; there must be some equipment that would integrate
everything. It was necessary, for example, to integrate various parts of
the power system - the accumulator battery storage and the converters into other kinds of energy
(gyroscopes, for instance, require alternating current). It was necessary to operate
the engines and all onboard systems, to make a cyclogram of pre-launch preparation,
and so on. It is the control system that turns on the engines at
I graduated from the Faculty of Equipment of the Moscow Aviation Institute
(MAI). MAI is distinguished by its broad education. They taught us oxygen equipment,
hydraulic equipment, radio equipment, and other kinds of devices. I was
finishing college after the war, and at that time and during war a lot
of new kinds of equipment appeared in Russia: American airplanes on
lend-lease contracts, captured German equipment, and alike. We began
studying all this. In the Faculty of Equipment and Instrument
Construction, the department of Viktor Naumovich Mil'shtein organized a
group to study new equipment during an additional, eleventh semester. I got into this group.
My major in the diploma read "mechanical engineer with
specialization in gyroscopic devices." For me, the idea of
integration was clear; I knew where every kind of equipment went.
Since then I have been doing integration. I was the principal
integration engineer on the R-7 rocket, and before that on the R-5. I worked
also on the very first rockets, the R-1 and the R-2, but as an ordinary
engineer, not as the principal. I was the principal developer on the N-1
and on the Buran. Since 1956, I have been Pilyugin's deputy in charge of equipment and
the test-and-launch complex. Pilyugin since died; his former post is no
longer call the Chief Designer, but the General Designer, and I am still the
deputy. Now I am the head of Integration Department. We currently
work on a joint project with Australia on the Aurora space-rocket system.
We have an Integration Division, which includes several departments. Other
departments work on integration in other projects. Someone is still
working on a project, and someone else is finishing, and he gets another
project. For other projects I work on the problems of stabilization
routes, of communication with radio operators, and so forth (the entire control system is
divided into separate functional routes).
There was a period in the 1960s when I was the head of the entire
Integration Division. In 1963 we moved from Aviamotornaya to the
Southwest district, and after 1963 I was the head of this division and was
working on the UR-500, on the Proton, and on the N-1. Almost 600 people
worked in that division.
Gerovitch: Did you attend any launches?
Priss: Yes, of course. I attended all the launches of the N-1 and the first, unsuccessful
attempt to launch the Buran. Then I left for Moscow and did not return
for the second attempt, but stayed in the Flight Control Center. I was
curious to see the role played by the Center. I had already been to the
launch site, and those who see the launch do not see the landing. Those who sit in the bunker
during the launch cannot be at the landing complex. And in the Center
you can see everything and know everything.
Gerovitch: Thank you very much for the interview.