Yuri Kondratyuk by Robert Godwin
From The Space Library
At the beginning of World War I a Ukrainian engineering student by the name of Yuri Kondratyuk had been drafted into the Russian army. In early 1917 Kondratyuk spent much of his time writing down his ideas for mounting a lunar expedition. The precise date of Kondratyuk’s work is still in dispute since it would not be published until many years later, however, Russian scholars researching in the early 1960’s concluded that at least some of his notebooks may be from as early as 1916. When interest in rocketry really began to blossom in the 1920’s Kondratyuk produced his notes and dated them to around 1918-1919. In another recollection he placed his ideas approximately from the date of Tsar Nicholas II’s abdication in February of 1917. He later wrote,
“Having achieved the first positive results in my work in 1917, and not suspecting at that time that I was not the first and only researcher in this field, I rested on my laurels for some time, while awaiting the opportunity to start experimenting.”
Regardless of the precise dates there can be little doubt that Kondratyuk was a talented and imaginative theorist. In his short essay entitled To Whomsoever Will Read In Order to Build, he asked the question, “Is it possible at present to make an interplanetary flight on a reactive device with known available substances?”
He began with the following statement, “Above all, do not be frightened by the theme of this paper nor distracted from the realization, difficult as it might be to comprehend, that from the theoretical viewpoint rocket flight into outer space is nothing astonishing or improbable.”
Kondratyuk put forth his two criteria,
- ) flights from Earth and back should not risk the lives of the passengers and
- ) the vehicle should be maneuverable.
To allow for the first stipulation he understood that the human frame can only endure moderate acceleration, that it requires a sealed cabin to sustain a viable atmosphere, and that the air must be recycled and the temperature must be held at a convenient level.
“All of the latter conditions are easily met, but the first requires some discussion; in order for the vehicle to be able to overcome the Earth’s gravitational pull, it must achieve a tremendous velocity (about 11 kilometers per second). In order to gain such a velocity without mortal consequences, acceleration must be imparted over a rather long period of time (in hours) and over a very long distance (hundreds of kilometers).”
In what is almost certainly a deferential reference to Jules Verne, he continued, “Any sort of cannon, in the conventional sense of the word, besides the fact that it cannot communicate the necessary velocity to the vehicle with today’s materials, is totally unsuitable, for the additional reason that a man seated in the projectile would be mashed to a pulp at the bottom of the vehicle.”
In his next statement he introduced what seems to be a very modern concept, the rail gun.
“It is conceivable, of course, to construct an electric “cannon” several hundred kilometers in length, which would comfortably supply a velocity of 11 km/sec, but such an item would be very costly and would not solve the problem of the return trip to Earth or of maneuverability.”
The idea of using a series of electro-magnets to propel a projectile was at least two years old at the time of Kondratyuk’s throw-away comment. Hugo Gernsback had mentioned such a device in the November 1915 issue of Electrical Experimenter. The principle involved lining up a string of electro-magnets along a rail, or a barrel, and then alternately turning them on and off in a consecutive linear sequence. The resulting magnetic fields would gradually “pull” a projectile along their length. In theory the projectile could be brought to escape velocity, although in 1915 the idea was primarily being considered to send explosive shells across huge distances, eliminating the problems that arise from using traditional explosives for propellant.
Kondratyuk also dismissed the idea of using a large “sling” because of the sheer scale necessary for such a device and again because it didn’t solve the problem of “returning to the Earth.” The importance of understanding the upper atmosphere was becoming self evident to both governments and scientific institutions. The aeroplane revolution was well underway. The previous November the British company Sopwith had introduced the world’s first Tri-plane. It was not to be a serious contender in the war over the skies of France but when one was shot down over German territory it was disassembled, reverse-engineered and improved to ultimately produce the Fokker Dr. 1 tri-plane, which in the hands of the Red Baron would terrorize Allied pilots for the remainder of the war.
While the British, French and Germans duked it out over the skies of France the Russian people were rebelling against the declining monarchy of Tsar Nicholas II. Tens of thousands of Russians and Ukrainians had already died in the war with Germany and food was becoming increasingly scarce. Many Russians could see little point in continuing the fight against Germany and their apathy was ripe for exploitation. Meanwhile, Yuri Kondratyuk seemed oblivious to the huge upheaval taking place in his home country and continued to concern himself with his theories of space travel.
“Is it possible in general theory for a reactive device to develop a velocity of 11 km/sec and to recover it for the return trip, and does this require dimensions that are impracticable or very difficult to realize? We will consider the rocket as a reactive device, since any other type that comes into mind is either unrealizable due to the enormous dimensions required, or the problem of realizing it calls for prior investigations which, at the moment, I am unprepared to carry out.”
It seems as though Kondratyuk was following the same lines of logic as Robert Esnault-Pelterie had done a few years earlier. What is of perhaps minor significance is that most Russian space scholars cannot be certain that Kondratyuk arrived at his theories entirely independently, nor can they place them with any accuracy to a specific date.
Kondratyuk was in fact born in the Ukraine as Oleksandr Ignatyevich Shargei. Because he served in the war wearing a Tsarist uniform he soon became a target for Lenin’s roving assassins and so he changed his name. However, earlier in his life he had attended Peter the Great Polytechnic college in St Petersburg, in fact it would seem that he was there studying engineering around the same time (or shortly after) that Esnault-Pelterie gave his lecture in that very same town. Kondratyuk’s mother was a French teacher and so it seems highly likely that the young engineering wizard may well have received more than an adequate schooling in the language of Moliére. Regardless of this it would seem that Kondratyuk would spend a considerable amount of time formulating his ideas for space travel and he supported his contentions with a considerable measure of mathematics. He discussed the energy yield of hydrogen/oxygen combustion; he readily comprehended the implications of intense acceleration on the human body and graphically demonstrated the need for using couches aligned perpendicularly to the direction of acceleration (a method still used today to help avoid the downward flow of blood from the brain during lift-off). He proposed earth-bound centrifuges as a means to experimenting with such large accelerations. He described in detail the potential of using an “electric” motor, something which we would today call an ion-engine.
“Even though right now a reactive device based on material emission seems very difficult and unlikely to me, it is nevertheless worth thinking about and working on; in the event that it succeeds, it promises to give as colossal a velocity as could be given to even the most gigantic rocket. It would perhaps be possible to test the Theory of Relativity.”
Such a gigantic ion-propelled starship is still the stuff of Star Trek and other science fiction, but an ion-propelled vehicle, Deep Space One, would finally be launched in 1998 and sent to flyby an asteroid and a comet.
Kondratyuk understood the benefits of staging and described the process in meticulous detail in his early paper. He also grasped the need for stability and suggested the Biaxial Astatic Gyroscope as the perfect mechanism to provide such stability. What is even more interesting is his theoretical work on rocket engines. He knew that if a rocket were to be propelled by hydrogen and oxygen it would be imperative that the two gasses mixed and burned cleanly. Any errant hydrogen building up in the combustion chamber would provide a recipe for disaster and so Kondratyuk proposed a method of alternating feeder pipes, laid out “to form a checkerboard pattern” so that the two gasses would be “rather finely stratified”. He even suggested that the fuel pumps would be driven by a turbine that would derive its power from the main fuel supply. This method is still used today.
Kondratyuk turned his keen eye to the subject of flight paths and trajectories concluding that:
“It is apparent that the sooner the escape from the atmosphere, the better. The main factor here is the first few tens of kilometers of the atmosphere, since beyond this limit its density becomes negligible. Therefore, the …method of flight must begin…almost perpendicular to the Earth’s surface, with the acceleration directed along a tangential course from the moment of takeoff.”
This is an enormously important concept. It was the subject of contention for some years that there are two ways to arrive at escape velocity. One is to fly straight up and the other is to fly horizontally thereby taking advantage of the fact that the curvature of the Earth will gradually fall away beneath you. The former suffers from the disadvantage of having to combat the full force of gravity in a short time frame and the latter suffers from the fact that you are fighting the forces of friction as you remain much longer in the dense air. It seems that Kondratyuk was keenly aware that a hybrid trajectory provides the best of both worlds, i.e. fly straight up for the first few minutes to get out of the thick air and then pitch your spacecraft’s nose down and fly horizontally to take advantage of the gradually receding curvature of the Earth to gain altitude. Once again, this method is still employed today. He further developed this theory and applied it to flying to the Moon and provided the equations to substantiate the trajectories.
So Kondratyuk understood many of the problems faced by would-be space voyagers and came up with good solutions for getting them into space, but what of the return? He knew that it would not suffice to put your adventurer into space if you couldn’t bring him home again.
“The atmosphere can be used to absorb the velocity of the vehicle so that we do not have to expend active substance (fuel) for this purpose….these methods, however, are far from simple to realize. It is said, for example, that meteors burn up from the friction of the air. They burn up because the mean velocity of the air molecules relative to the meteor is enormous. For this reason it becomes hot and burns up.”
He recognized that the aerodynamics of the vehicle were extremely important and he proposed a polished surface on the vehicle (i.e. no extrusions hanging out, like the tile spacers that seemed to be continually hanging out of the Space Shuttle) however, at this point, he can be excused for his inclination to keep the vehicle flying nose first. At the time of writing, practically everything that was known about high speed aerodynamics came from ballistics (i.e. guns). Since artillery shells and bullets seemed to fly most efficiently sharp-end first, it was assumed that this was the best and only way to accomplish such things. Kondratyuk proposed that his returning spacecraft not only fly nose first but that it be stabilized by gyroscopes supplemented by what looked like the keel of a ship. It seems odd that he didn’t immediately recognize that his keel was essentially a wing and would undoubtedly have had the opposite to the desired effect of stability (at least without another identical opposing wing). Kondratyuk can be forgiven this error since the research into providing successful re-entry continued to foil engineers until the 1950’s when it was discovered that a returning hypersonic projectile was in fact much more stable if it returned blunt-end first (as long as a method for dispersing the heat was provided.)
Kondratyuk was still not quite finished. He proposed a spacecraft that used solar radiation for propulsion, a solar sail, and he suggested an assortment of mirrors and reflectors to increase the potential thrust provided by high energy particles streaming from the sun (the solar wind). (He may well have read the two recent novels written by his fellow countryman Boris Krasnogorskii which described this idea.) In an almost casual aside he said,
“Reflectors could also be used to reflect waves from wireless telegraph stations to send them wherever necessary.”
Although he didn’t specify optimum orbits for such reflectors it is undeniable that he was discussing the communication satellite.
Finally, he proposed an entire architecture for space exploration:
“Flight should be executed in line with the Earth’s rotation (as should the landing) in order to utilize, rather than to incur harm by the considerable velocity of the Earth’s rotation.
“It is advisable to proceed as follows: first, send out from Earth a base with supplies but without personnel, such that it will automatically be made an Earth satellite, then send up a vehicle with people; after flying to the base, they will pick up any necessities and continue the flight, the base continuing to circle the Earth.
“To make a stopover at some other planet…it would be more advantageous, therefore, not to land the entire vehicle on the planet but to send a satellite (around the planet), in fact just that part of the vehicle that will be needed for landing on the planet and returning to the vehicle.
“On the return flight, provisions are again picked up on the base and the return to Earth completed. Such a method is appropriate in that, by sending ahead the main bulk of the load without people, we are not held back by limited acceleration and could even utilize the cannon principle.”
These are some of the most important fundamental concepts for planetary exploration, all summarized by Kondratyuk during World War I. There can be little doubt, even allowing for the mystery of the dates ascribed to these comments, that Kondratyuk was a formidable theorist and although a crater on the moon bears his name he is almost entirely forgotten today.
