Sputnik: The Launch of the Space Age

Born just over four years into the Space Age, I grew up in the 1960s and 1970s enthralled with the succession of space missions which ultimately inspired me to become a physicist who has spent most of his career working in space-related sciences (see “When I Thought My Dad was an Astronaut“) not to mention a historian writing about space exploration. During a trip to Washington, DC in May 1984 to attend a Society of Physics Students conference, I had a chance to make my first visit to the National Air and Space Museum and saw hanging in one of the display halls a replica of the satellite which started it all: Sputnik. Launched by the Soviet Union on October 4, 1957, the orbiting of this first artificial Earth satellite had an unforeseen impact on the world and started a cascade of events which has impacted the lives of not only budding space enthusiasts like myself, but all of us with the family of new technologies and capabilities it introduced.

The Dream

The roots of Sputnik stretch back three-quarters of a century before its successful launch.  Starting in 1883, a Russian schoolmaster named Konstantin Eduardovich Tsiolkovsky (1857-1935) became the first person to begin seriously addressing the science and engineering behind spaceflight. During the next half century he published a long series of works detailing the scientific principles behind such an endeavor. In the years to follow, Tsiolkovsky’s writings inspired a generation of incredibly talented and driven Soviet engineers and scientists who began the difficult task of developing the technologies needed to make the dream of spaceflight come true. With the availability of the German V-2 rocket technology at the end of World War II, scientists and engineers not only in the Soviet Union but in America and Europe as well soon realized that the first step into space – an Earth-orbiting satellite – was within reach.

Portrait of Chief Designer Sergei Korolev who led the effort at OKB-1 to build the first ICBM and first satellite. (RKK Energia)

In August of 1946 Sergei Pavlovich Korolev (1907-1966), who had survived his imprisonment during Stalin’s pre-war purges, became the Chief Designer of OKB-1 (the Russian acronym for Experimental Design Bureau 1) which was then part of the larger organization called NII-88 (Scientific Research Institute 88). Under Korolev’s direction, OKB-1 (which is the direct ancestor of today’s Russian aerospace giant, RKK Energia) successfully duplicated the V-2 design with a rocket designated R-1. Not long afterwards, subsequent rocket design innovations far exceeded this rocket’s limited capabilities with the improved R-2 and R-5 ballistic missiles as well as their variants. While Korolev’s superiors were primarily interested in the military applications of this new technology, Korolev and his closest colleagues always had the dream of spaceflight in the back of their minds with some of their early missiles adapted to lift scientific payloads on ballistic trajectories into space. In October of 1951 one of Korolev’s deputies, Mikhail Klavdievich Tikhonravov (1900-1974), presented a feasibility plan for an Earth-orbiting satellite showing that it was possible.

The R-1 was a Soviet copy of the German V-2 rocket built by OKB-1. As in the US and elsewhere, the V-2 would serve as the springboard to develop satellite launchers. Click on image to enlarge. (RKK Energia)

Efforts to launch a satellite remained subordinate to the need to develop new weapons until 1954 when planning for the International Geophysical Year (IGY) started. The intent of this unprecedented international scientific collaboration was to obtain data on Earth’s upper atmosphere and its interaction with the Sun during the peak of the next sunspot cycle between July 1957 and December 1958. Probably spurred by these developments, Korolev published a scientific paper on Earth satellites in 1954. On January 9, 1955 a group of Soviet scientists, who had been inspired by Korolev’s paper, met to promote his satellite project. They ultimately persuaded the Presidium of the Academy of Sciences to mail a brief questionnaire to several hundred Soviet scientists for their thoughts on the potential uses of satellites. The responses ranged from very positive to a terse “Fantasy!” but on April 15, 1955 the Academy of Sciences established a “Permanent Commission for Interplanetary Travel” to study the launching of a Soviet satellite and missions beyond.

Behind the scenes Korolev was busy selling the Soviet leadership on the idea of using one of  his new long-range missiles not only to launch a satellite but also men into orbit and probes to the Moon. On July 29, 1955 the Americans announced that they would launch a satellite as part of their IGY contribution. Three days later the Soviets made a similar announcement that seems to have been largely ignored in the West as yet another empty Soviet boast. With the clock already ticking, Korolev formally submitted his satellite proposal to the Soviet leadership on August 29, 1955.

The Rocket

While Korolev’s proposal only obliquely referred to the rocket that would make these missions possible, he intended from the start to use the new R-7 (also known in the West by the NATO codename “Sapwood” or SS-6). The genesis of its design can be traced back to a proposal presented to Korolev by Tikhonravov in mid-1947 called the “Rocket Packet”. This long-range missile concept used parallel staging and called for a cluster of five identical rockets to ignite simultaneously at liftoff. From 1949 to 1951 MIAN (the Mathematical Institute of the Academy of Sciences) under the direction of Korolev’s good friend and ally, Academician Mstislav Vsevolodovich Keldysh (1911-1978), began detailed studies of this concept. By December of 1950 OKB-1 began feasibility studies of a number of long-range missiles concepts that would build on their previous work. This led to a design study called “T-1” which employed Tikhonravov’s innovative rocket packet concept.

Tikhonravov (left) and Korolev in 1947 at a celebration of the 90th anniversary of the birth of Tsiolkovsky. (TASS)

The design, whose study was authorized in February of 1953, called for a five-unit rocket packet with a launch mass of up to 200 metric tons that was capable of carrying a three metric ton payload over an astounding range of 8,500 kilometers. After the detonation of the Soviet’s first H-bomb in October of 1953, however, it became apparent that a missile with a five-plus metric ton payload capability would be required to carry this weapon over intercontinental distances. A scaled up version of the T-1 was immediately proposed to fill this requirement. On May 20, 1954 OKB-1 was given the authority to begin designing article 8K71 and the R-7 was born.

Korolev (left) with Igor Kurchatov (the “father” of the Soviet H-bomb) and Mstislav Keldysh in 1956. (Keldysh Museum)

The R-7 was a truly enormous rocket whose size would not be surpassed in the West until the development of the Saturn I. It consisted of a stepped, cylindrical core called Blok A surrounded by four tapered strap-on boosters designated Bloks B, V, G, and D – the next four letter in the Cyrillic alphabet. The total length of the missile, including warhead, was about 34 meters and it had a launch mass of 274 metric tons. The R-7 was designed so that the core and all four boosters would ignite on the pad, thus avoiding the then-untried procedure of starting large engines at high altitude. After the boosters of the R-7 had exhausted their propellants 120 seconds after liftoff, they would be jettisoned. The group of American engineers developing the smaller Atlas missile at this same time took a different approach to solve the same problem by igniting all of its engines on the pad then discarding just the rocket’s booster engines and their support structure when they were no longer needed (see “The First Atlas Test Flights“). After the four boosters were dropped, the Blok A core would then continue alone until the proper velocity had been reached 320 to 330 seconds after liftoff at which time the warhead would be released to continue its ballistic path towards its distant target. The R-7 was designed to throw a five-megaton nuclear warhead with a mass of 5,400 kilograms over a distance of 8,000 kilometers. This range would be sufficient to hit any target in Eurasia as well as most of Africa and North America including much of the continental US. The R-7 was truly an Intercontinental Ballistic Missile (ICBM).

This cutaway drawing shows the details of the original R-7 or 8K71 ICBM used in early test flights. Click on image to enlarge. (RKK Energia)

At lift off the engines of the R-7 generated an unequaled 3,904 kilonewtons of thrust. Each booster of the R-7 was powered by an RD-107 engine that produced 795 kilonewtons of thrust at sea level using kerosene and liquid oxygen (LOX) as propellants. The core used an engine of similar design called the RD-108 that produced 726 kilonewtons of thrust at sea level and 912 kilonewtons at altitude. These engines were designed and built by OKB-456 under the direction of Valentin Petrovitch Glushko (1909-1989). The RD-107/108 consisted of a single turbopump assembly feeding a cluster of four combustion chambers. The major external difference between the RD-107 and 108 was that they incorporated two and four small gimbaled vernier engines, respectively, to steer the R-7 and trim its velocity. The RD-108 also ran at a lower thrust level so that it could operate up to 210 seconds longer than the boosters’ RD-107 engines and its nozzles were optimized for operation at high altitudes.

Pictured here is the RD-107 engine used to power the four boosters of the R-7 rocket. A single turbopump assembly provide propellant to four large thrust chambers and two smaller vernier engines used to steer the rocket.

Glushko had unsuccessfully tried to develop the larger single-chamber RD-105/106 engines from 1951 to 1953 that would have provided the T-1 with a total liftoff thrust of 2,700 kilonewtons. In the RD-107/108 concept, however, each chamber produced about the same amount of thrust as the successful single-chamber RD-100 which powered the Soviet R-1. The clustered nozzle approach of the RD-107/108 bypassed numerous problems such as combustion instability encountered during the work on the larger RD-105/106 so that development could proceed more quickly. Test firings of a single chamber of the RD-107/108 began in the middle of 1955 followed by tests with a pair of chambers in December. In January of 1956 trials with the full four-chamber configuration started.

The Satellite

These events could not have come soon enough for Korolev. On January 30, 1956 the Soviet government authorized Korolev’s satellite program. Korolev gave Tikhonravov and his design team in Department No. 9 the job of building the heavy satellite designated “Object D”. Object D, which would have a mass of about 1,000 to 1,400 kilograms and carry 200 to 300 kilograms of geophysical instrumentation, would be launched into orbit using a special version of the R-7 designated 8A91. The 269 metric ton 8A91 launch vehicle would be similar to the 8K71 except that it would be stripped of all the equipment needed to precisely guide an ICBM and it would use specially modified versions of the RD-107/108 engines. These engines would be lower thrust, more efficient versions of engines used on the ICBM configuration and would produce 3,806 kilonewtons of thrust at liftoff. Seven missiles were set aside for Korolev’s satellite launches which were to be conducted as part of the larger R-7 development program.

This Russian diagram shows the configuration of the Object D satellite as it was eventually flown. Click on image to enlarge. (RKK Energia)

Progress on the development of the R-7 proceeded quite quickly through 1956. That summer saw the first static test firings of a single strap-on booster. The first static tests of the Blok A core started in August and by the winter of 1956-57 the entire R-7 was being static tested at a facility outside of Moscow. As a result of Korolev’s growing influence as well as his skill as an engineer and manager, OKB-1 became independent of the more research and development oriented NII-88 in October of 1956.

Since the existing Soviet missile test range at Kapustin Yar near the Aral Sea was too small to handle long-range flights of ICBMs (or satellite launch vehicles), a new launch facility was required for the R-7. On May 31, 1955, construction had begun on the new R-7 launch facilities near the town of Tyuratum in Soviet Kazakhstan. This new facility, initially known by its railway stop designation of “Tashkent 50”, was designed and built by the Moscow-based design bureau GSKB SpetsMash under Vladimir Pavlovich Barmin (1909-1993). Later these facilities would become the focus of today’s sprawling Baikonur Cosmodrome. By December of 1956 a nonflight R-7 test article, designated 8K71SN, was delivered to Tashkent 50. On March 4, 1957 the first R-7 launch pad was completed and fit tests using the 8K71SN began.

A view of the original launch pad for the R-7 built in what would become the Baikonur Cosmodrome. (RKK Energia)

While the preparations for the satellite project were well underway, a Soviet delegate to a conference of the Special Committee for IGY held in Barcelona, Spain announced on September 11, 1956 that the Soviet Union would launch a satellite during the IGY. Unfortunately, progress on the complex Object D satellite was proceeding more slowly than originally hoped. The main problem was delays in the delivery of instruments which could operate in space – a new realm with unforeseen engineering challenges. In mid-November 1956, Tikhonravov suggested to Korolev that a much less complex satellite called “Object PS” (“PS” standing for the Russian acronym for “Simple Satellite”) could be quickly developed and launched. In its initial incarnation, Object PS would be about a half a meter across, have a mass of 40 to 50 kilograms and only carry a simple transmitter. After some deliberation, Korolev adopted the plan in December and moved to implement it. Initially there was some resistance to this change in plan, most notably from Academician Keldysh, but it was quickly approved and design work started with two satellite launches planned between April and June 1957 following a couple of successful test flights of the R-7.

Blueprints for Object PS which would become Sputnik. Click on image to enlarge. (RKK Energia)

In its final form, Object PS turned out to be a simple 58-centimeter polished metal sphere with four antennas and a mass of about 80 kilograms. Pressurized to aid in thermal control, Object PS was equipped with a pair of battery-powered D-200 type transmitters operating at the frequencies of 20 and 40 megahertz. The radio signals would be frequency modulated to transmit information on the satellite’s interior temperature and pressure. Studies of these transmissions would also provide information on the propagation of radio signals through the upper ionosphere. Observations of  the changes in the satellite’s orbit would give scientists much needed data on the density of the upper atmosphere and the precise shape of the Earth – tasks made easier by the simple spherical shape of the satellite. All of these data would be a valuable contribution to the IGY.

This cutaway drawing shows Object PS and how it was mounted atop of its 8K71PS launch vehicle. Click on image to enlarge. (RKK Energia)

Since the purpose-built 8A91 satellite launch vehicle would not be available yet, Object PS would have to be launched into orbit using a stripped down version of the R-7 designated 8K71PS. It would be nearly identical to the 8K71 ICBM save for the absence of the warhead and 300 kilograms of extraneous radio telemetry equipment. A payload adapter, a separation system, and a nose cone were also added to the top of the missile to accommodate the small satellite. The shutdown sequence of the R-7 core’s RD-108 engine was also simplified so that it would burn until its propellants were exhausted thus guaranteeing the highest possible velocity. All together, the 8K71PS, whose spent Blok A stage would enter orbit along with the satellite, was 7 metric tons lighter than the 8K71 ICBM. While this plan might not have been elegant engineering, at very least the launch of Object PS would demonstrate that a satellite could be placed into orbit and provide practical experience for the eventual launch of the more advanced Object D. In addition, Object PS would still be much more massive than the 11-kilogram Vanguard satellites the US was planning to launch during the IGY (see “Vanguard TV-3: America’s First Satellite Launch Attempt“).

Testing the R-7

In March of 1957 OKB-1 delivered the first flight model of the R-7 to the new facility at Tashkent 50. Finally at 7:01 PM Moscow Time on May 15, 1957 the first R-7, serial number M1-5, was launched on a test flight carrying a dummy warhead filled with telemetry equipment. All seemed to be going well until 98 seconds after launch when one of the strap-on boosters broke away from the core. Afterwards the rocket tumbled out of control and crashed 400 kilometers downrange. An investigation showed that a type of excessive longitudinal vibration, known as “pogo”, started a fuel leak that lead to a fire in the booster’s engine compartment. Eventually the RD-107 engine overheated and shut down leading to the booster breaking away. This failure along with delays building and testing the PS-1 satellite made the originally envisioned satellite launch date of May or June impossible.

An R-7 ICBM being prepared for a test flight. (RKK Energia)

Undeterred by the failure, another R-7 serial number M1-6 was modified and prepared for flight. A launch attempt was aborted at the last second on June 9 followed by two more aborts on June 10 and 11. The uncooperative rocket was removed from the pad and inspected. Eventually it was discovered that an incorrectly installed nitrogen valve was the source of the problem. In the mean time another R-7, serial number M1-7, was erected on the pad and launched at 3:53 PM Moscow Time on July 12. This time a short circuited battery caused a malfunction in the ascending rocket’s control system which sent the R-7 spinning until it broke up after only 33 seconds of flight. Meanwhile on July 9, 1957 the Soviets publicly announced that a satellite was being prepared for launch as well as the radio frequencies it would use. Once again the United States and the rest of the West seemed to dismiss the announcement as empty Soviet propaganda.

The timing of these R-7 failures could not have been worse for Korolev. He had been constantly under attack from rival Chief Designers for much of his career but, with the string of R-7 failures, his support in the Soviet government was beginning to falter. At one point he even lost the support of his staunchest ally in the upper echelons of Soviet government, Premier Nikita Khrushchev. It was Korolev’s lowest point and the very future of OKB-1 was at stake.

The launch of the first successful R-7 test flight on August 21, 1957. (RKK Energia)

Knowing how close he was to success, Korolev stubbornly pushed forward with work on the R-7. Finally at 3:15 PM Moscow Time on August 21, 1957 Korolev’s fortunes changed when R-7 serial number M1-8 was successfully launched. The missile sent a dummy warhead to its target on the Kamchatka peninsula 6,500 kilometers away. While the warhead broke up at an altitude of ten kilometers during descent because its thermal protection was inadequate, the R-7 design itself was vindicated and OKB-1 was saved. Although much work still lay ahead to fine tune the R-7 as well as develop a viable warhead design, the Soviet government officially announced that they possessed an operational ICBM only five days after this first successful test. The impact in the West was slight at best.

The Launch

With a successful test of the R-7 under his belt and OKB-1 future secure for the moment, Korolev was in a position to seek final approval for the launch of an Earth satellite. In early September 1957 Khrushchev gave his approval but for his own political reasons. He felt that a successful satellite launch would show his enemies in the Party that he could lead the Soviet Union towards a glorious future. It would also demonstrate to the West that the Soviets did indeed possess an ICBM capability, thus serving as a deterrent to any outside aggression. Finally, it would give Khrushchev the excuse he needed to reorganize the Soviet military and form the Strategic Rocket Corps on equal footing with the other branches of the military.

This cutaway drawing shows the 8K71PS rocket used to launch Sputnik. Click on image to enlarge. (RKK Energia)

With Khrushchev’s blessing, Korolev set out to launch a satellite as soon as possible. The 8K71 missile serial number M1-10 was stripped of non-essential systems and converted into 8K71PS serial number M1-1PS. Korolev had hoped to launch PS-1 in time for the 100th anniversary of the birth of Tsiolkovsky on September 18 but work on the required hardware could not be finished in time. Still, the anniversary was marked by an announcement by Radio Moscow that a satellite launch was imminent with the West again turning a deaf ear. On September 20, Korolev left OKB-1 in Moscow for Tashkent 50 so he could personally supervise the final preparations for the satellite launch. During this time he lived in a small wood framed house with the hanger-like MIK assembly building a ten minute walk away in one direction and the launch pad ten minutes away in the other. On the night of October 2 the 8K71PS carrying PS-1 left the MIK for the launch pad. The next day the rocket was erected on the pad and it was  fueled for the coming launch.

A technician shown working on Object PS before launch.

During the day of October 4 several attempts were made to launch the R-7 but they were repeatedly delayed due to a string of technical glitches. As night fell, Korolev decided to make one more attempt. As Korolev himself was counting down the final minutes to launch from a bunker 100 meters from the pad, a lone bugler briefly appeared on the concrete apron to blow a long series of trumpet blasts to announce the imminent historical event. Finally at 10:28:04 PM Moscow Time, the 20 large thrust chambers of the R-7 ignited lifting the missile and its payload off the launch pad. The rocket quickly gained speed, pitched on command towards the northeast and disappeared into the night sky.

The launch of Sputnik on October 4, 1957. (RKK Energia)

Korolev and the rest of the people who witnessed the sight had no way of knowing if the satellite made it to orbit. A radio receiver and loud speakers were set up in the MIK where everyone had gathered to wait to hear from Object PS as it flew overhead for the first time. An hour and a half after launch the now famous “beep, beep, beep” from the satellite’s transmitter, now designated “Sputnik” (Russian for “fellow traveler”), echoed throughout the MIK. There was now no doubt about the outcome of the launch: The 83.6 kilogram Sputnik was successfully placed into a 228 by 947 kilometer orbit with an inclination of 65.1° and a period of 96.17 minutes.

A painting by Soviet space artist, Andrei Sokolov, showing Sputnik separating from its launch vehicle after reaching orbit.

After the cheers of the people gathered in the MIK died down, Korolev stood before them and spoke:

“The conquering of space has begun. Today we have witnessed the realization of a dream nurtured by some of the finest minds who ever lived. Our outstanding scientist Tsiolkovsky brilliantly foretold that mankind would not forever remain on the Earth. Sputnik is the first confirmation of his prophecy. We can be proud this was begun by our country.”

With these words, the Space Age had begun.

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Related Reading

“Vanguard TV-3: America’s First Satellite Launch Attempt”, Drew Ex Machina, December 6, 2017 [Post]

“America’s First Satellite… Almost”, Drew Ex Machina, October 4, 2015 [Post]

General References

James Harford, Korolev: How One Man Masterminded the Soviet Drive to Beat America to the Moon, John Wiley & Sons, Inc., 1997

Asif A. Siddiqi, Sputnik and the Soviet Space Challenge, University Press of Florida, 2003

M.K. Tikhonravov, “The Creation of the First Artificial Earth Satellite: Some Historical Details”, Journal of the British Interplanetary Society, Vol. 47, No. 5, pp. 191-194, May 1994

Timothy Varfolomeyev, “Soviet Rocketry That Conquered Space, Part 1: From First ICBM to Sputnik Launcher”, Spaceflight, Vol. 37,  No. 8, pp. 260-263, August 1995

Timothy Varfolomeyev, “Correspondence: Soviet Rocketry”, Spaceflight, Vol. 38, No. 1, p. 31, January 1996

From First Satellite to Energia-Buran and Mir, RKK Energia, 1994

Raketno-Kosmichekaya Korporatsiya Energia Imeni S.P. Koroleva 1946-1996 (in Russian), RKK Energia, 1996