During the six months following the launch of the Soviet Union’s second satellite, Sputnik 2 (see “Sputnik 2: The First Animal in Orbit”), public attention was focused on American efforts to catch up by whatever means available. By the end of April 1958, the ABMA (Army Ballistic Missile Agency) had orbited two satellites in three attempts while America’s original “official” satellite program, Project Vanguard, had managed to get only one small test payload into orbit after four tries (see “Explorer 1: America’s First Satellite” and “Vanguard 1: The Little Satellite that Could”). While these satellites, with a total mass of only 30 kilograms, were dwarfed by the 592 kilograms of useful payload orbited by the Soviet Union, they still made some important discoveries including that of the Earth’s Van Allen radiation belt. But while leaders in the US debated the Soviet’s capabilities, the danger they might pose and America’s response, everyone wondered when the next Soviet satellite would be orbited and what surprises it would bring.
The Third Soviet Satellite
Unknown to everyone in the West at the time, engineers and scientists associated with OKB-1 (Experimental Design Bureau-1) under the leadership of aerospace pioneer Sergei Korolev were quite busy during this hiatus in Soviet satellite launches. After the launch of the first two Sputniks using stripped down versions of the R-7 ICBM known as 8K71PS (see “Sputnik: Launch of the Space Age”), development flights of the 8K71 ICBM version of the R-7 continued with launches on January 30, March 29, and April 4 of 1958. While none of these tests were completely successful, the experience gained with each flight led to incremental improvements in the performance and reliability of this giant machine.
Portrait of Chief Designer Sergei Korolev who led the effort at OKB-1 to build the Soviet’s first ICBM and satellites. (RKK Energia)
The R-7 was a truly enormous rocket whose size would not be surpassed in the West until the introduction of the Saturn I (see “The Largest Launch Vehicles Through History”). Early development models of the 8K71 had a total length of about 34 meters (including the warhead) and a launch mass of 274 metric tons. The R-7 and its variants used a unique parallel staging arrangement where the RD-108 engine of its core, designated Blok A, and the similar RD-107 engines its four strap-on boosters, designated Bloks B, V, G, and D (the next four letter in the Cyrillic alphabet) would ignite on the launch pad. This was done in order to avoid the then untried procedure of igniting large engines in flight at high altitude. Once the boosters of the R-7 had exhausted their propellants 120 seconds after liftoff, they would be jettisoned. Afterwards, 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.
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)
By the spring of 1958 the first R-7 rocket specifically designed to launch satellites, known as the 8A91, was nearly ready to fly. The 269 metric ton 8A91 launch vehicle was similar to the 8K71 ICBM except that it was stripped of all of test equipment used during development flights as well as systems for precisely guiding an ICBM. It also used specially modified versions of the RD-107 and RD-108 engines employed in boosters and core, respectively. These engines were lower thrust, more efficient variants of the units used on the ICBM configuration and produced 3,806 kilonewtons of thrust at liftoff. The initial payload for this new launch vehicle was the Object D satellite developed by a team headed by Mikhail Tikhonravov at OKB-1. Originally meant to be the first Soviet satellite when Korolev’s proposal was authorized by the Soviet government on January 30, 1956, development of Object D and its 8A91 launch vehicle dragged on almost a year longer than originally anticipated. But by the spring of 1958, everything was finally ready for launch.
As with the launch of Sputnik 2, the timing of the third Soviet satellite launch was set by Soviet Premier Nikita Khrushchev’s political agenda. Thanks to Korolev and his team at OKB-1, the quick development and launch of the first two relatively simple Sputniks was able to secure an early lead in the Space Race for the Soviet Union. But Khrushchev, who took full advantage of the propaganda value of this lead, wanted more space spectaculars to further improve Soviet communism’s image abroad and deter Western aggression.
While there were a range of projects under development which could supply Khrushchev with another important space first, none would be ready until at least the summer of 1958. The only hardware at hand was the nearly completed Object D and its launch vehicle. But to Khrushchev, who was not interested in science for its own sake, the launching of just another satellite would hardly be spectacular. As a result, Khrushchev’s enthusiasm for this project was lukewarm at best. But with nothing else available, the launch of Object D was set to occur before the upcoming Italian general election on May 25, 1958 in the hope of influencing its results. An 8A91 rocket and an Object D satellite, along with a backup to ensure a successful mission, were prepared for launch.
An Orbiting Research Laboratory
While it did not matter to Khrushchev, Object D promised to make the most comprehensive geophysical survey of the near space environment for the IGY (International Geophysical Year) – an international scientific cooperative effort to study the Earth and its interaction with the Sun that ran from July 1, 1957 to December 31, 1958. Object D was roughly conical shaped with a height of 3.57 meters and a base diameter of 1.73 meters. It consisted of a magnesium alloy frame covered with polished aluminum panels. Like the earlier Sputniks, its interior was pressurized with nitrogen in order to provide a laboratory-like environment for its internal equipment. A fan circulated the internal nitrogen atmosphere of the satellite and 16 external louvers would open and close as needed to help maintain the internal temperature. While using a pressurized interior added to the mass of the satellite, it would become the standard Soviet aerospace engineering practice because it helped ease thermal control issues and simplified ground testing of equipment.
This Russian diagram shows the configuration of the Object D satellite as it was flown. Click on image to enlarge. (RKK Energia)
In order to help cut development time and simplify the design further, it was decided that Object D would not be outfitted with an attitude control system and would be left to drift instead. Like its predecessors, Object D would be powered by a bank of silver-zinc batteries which would allow radio transmissions for about six weeks. Also included was a technology experiment consisting of small banks of silicon solar cells – the second satellite to do so after the diminutive Vanguard 1 (see “Vintage Micro: The Original Nanosatellite”). In addition to providing an assessment of how solar cells would fare in the space environment, they could provide power to the satellite’s tracking beacon and cosmic ray detector allowing them to operate for a much longer period of time than the battery-powered equipment. With a total mass of about 1.3 metric tons, Object D was more than twice as massive all the previously launched Soviet and American satellites combined.
In addition to being the largest satellite ever launched up to this point, Object D would be the most sophisticated scientific satellite ever orbited. A commission of scientists and engineers established by the Soviet Academy of Sciences headed by Korolev’s ally, Academician Mstislav V. Keldysh, with Korolev and Tikhonravov as his deputies, decided what instruments Object D would carry. In the end they chose a dozen experiments that investigated virtually every area of interest to IGY scientists around the world. These included direct measurements of the density, pressure, and composition of the Earth’s upper atmosphere. Measurements of the concentration of charged particles, cosmic rays, solar radiation, terrestrial magnetic and electrostatic fields, as well as the flux of micrometeorites would also be made. To round out the investigations, radio propagation studies would be performed using the satellite’s transmitters that operated at frequencies of 20 and 40 MHz. All together, 968 kilograms of instrumentation and power supplies would be carried inside the pressurized interior of Object D with useful data being returned from the instruments for periods of one week to a month or more, depending on the investigation.
A view showing the internal equipment of Object D. (RKK Energia)
To support all this instrumentation, Object D was equipped with a sophisticated high speed telemetry system called Tral-D that would handle the flow of data. A tape recorder was also included in the system to store all of the instruments’ observations when the satellite was not in contact with Soviet tracking stations. Its contents could be downloaded upon command via radio when the satellite was over Soviet territory. In order to maximize the scientific return of the mission, it was decided to place Object D in an elliptical orbit with a apogee of at least 1,500 kilometers. Combined with the impressive array of instruments and the tape recorder, this orbit would allow the radiation belts first observed by the American Explorer 1 satellite to be systematically mapped in detail by a large array of instruments for the first time.
Sputnik 3 is Launched
The Blok A core of the first flight-ready 8A91, serial number B1-2, arrived at the NIIP-5 Test Range (today known as the Baikonur Cosomodrome) in Soviet Kazakhstan on April 5, 1958 followed five days later by its quartet of boosters. While the hope had been to launch the new spacecraft on April 20 in commemoration of the upcoming 88th anniversary of the birth of Lenin, preparations took longer than expected. Launch finally took place at 12:01 PM Moscow Time on April 27 with Object D mounted beneath a conical aerodynamic fairing on the nose of its new launch vehicle. All seemed to going as planned but as the rocket ascended, longitudinal resonance vibrations (an effect called “pogo”) in the strap-on boosters increased in intensity as the propellant tanks emptied. The launch vehicle finally shook itself apart about 88 seconds after launch. The debris reached a peak altitude of 13 to 15 kilometers and fell to the ground some 69 to 225 kilometers downrange.
The first 8A91 satellite launch vehicle disintegrated during ascent on April 27, 1958.
The remains of the still top secret Object D were subsequently recovered after a low profile search to keep it away from prying eyes. While the flight was a total loss, the ruggedness of the payload was aptly demonstrated when some of the would-be satellite’s instruments continued to operate despite the explosively short ride. Unlike the American satellite program whose failures were known (see “Vanguard TV-3: America’s First Satellite Launch Attempt”), the Soviet government made every effort to conceal the failure for years to come.
After this first Soviet satellite launch failure, the backup 8A91 launch vehicle, serial number B1-1, was quickly prepared to orbit a spare Object D which was completing its final assembly and testing. But while prelaunch checks of the payload’s instruments showed everything to be in order, there were indications that the data tape recorder was not operating properly. The engineer in charge of the telemetry system and recorder, Chief Designer Alexei F. Bogomolov of OKB MEI, did not want to be the one to hold up this important launch. Bogomolov insisted that the errant signals from the recorder were the result of electromagnetic interference from other sources in the testing room and that the unit was actually working properly. With increasing pressure from the Kremlin to launch by mid-May, Korolev accepted Bogomolov’s explanation despite the protests of the other engineers and preparations to launch the second Object D proceeded.
Sputnik 3 shown being prepared for launch.
Finally at 10:00:35.5 AM Moscow Time on May 15, 1958 the second 8A91 rocket lifted off from its pad in the Kazakh steppes for the fourth Soviet satellite launch attempt. This time the rocket operated perfectly placing its 1,327 kilogram payload, now called Sputnik 3, into a 230 by 1,880 kilometer orbit inclined 65.2° to the equator. Once in orbit, Sputnik 3 separated from the spent core of its launch vehicle to start its mission. While this flight did not give the Soviets any new space firsts, the immense size of the satellite was a shock to the West and provided leaders with more evidence that the Soviet Union possessed an viable ICBM capability.
The launch of Sputnik 3 on May 15, 1958.
But as the Soviet propaganda machine hailed their latest space success, in reality all was not well with the new satellite. Much to the chagrin of everyone involved in the project, the suspect tape recorder failed to operate once in orbit. Because of the secrecy associated with the project, Soviet authorities did not share with the rest of the world the information needed to receive and decode Sputnik’s signals thus losing the opportunity to recover data gathered over the most of the globe. This limited the new Sputnik’s measurements to the times it was over Soviet territory. Since Sputnik 3 was near the perigee of its orbit during these periods, it could only make observations up to an altitude of about 1,000 kilometers. While extremely useful data could still be gathered, project scientists would be unable to make the systematic series of global measurements they hoped to make.
This illustration provides a modern view of the Van Allen radiation belts. (JHUAPL/LASP)
It was only after the scientific results of the first American and Soviet satellites were studied in detail was it was realized how the loss of the tape recorder prevented Soviet scientists from making an important scientific find. After the discovery in late 1958 by American scientists that the Van Allen radiation belt is in fact composed of distinct inner and outer portions, Soviet physicist Sergei Vernov realized that Sputnik 3 had returned the first measurements from the outer belt. But because of the loss of the tape recorder, he and his colleagues were unable to place their spotty data into the broader context required to recognize the significance of their observations.
Diagram showing where Sputnik 3 entered (filled circles) or exited (open circles) the Van Allen radiation belt during its overpasses of the Soviet Union. Unfortunately only the edge of the inner belt where it dips close to the Earth was detected. (Vernov)
With hindsight, Soviet authorities claimed on March 6, 1959 that Vernov had discovered the outer belt and that this result had actually been reported at an IGY meeting the previous August – long before the American’s announcement of their discovery. Unfortunately the Soviet claim was rejected since such a statement was not explicitly made in their August 1958 report and there was no way to unambiguously identify the outer belt from the Soviet data published up until that time. Still, a popular Russian joke at the time proposed that the Van Allen belt be renamed the “Van Allen-Vernov Belt”.
Aftermath of the Mission
Sputnik 3 transmitted a total of 100,000 measurements of the space environment before its primary data transmission system failed on June 3, 1958. The solar-powered radio beacon and associated cosmic ray detector continued to return useful data until the orbit finally decayed and the satellite burned up on May 6, 1960. Despite the fact that the mission was largely successful, there was no support in the Soviet government for follow-up missions. Khrushchev was far more interested in space spectaculars than the systematic exploration of space. This combined with limited resources at OKB-1 and its network of other design bureaus resulted in continual reassessments of project priorities during 1958.
In the end, three nearly-completed scientific satellites in the shops at OKB-1 that were to follow Sputnik 3 into Earth orbit were never launched. Development of attitude-controlled versions of the Object D and other proposed satellites that would use the 1.5 metric ton payload capability of the 8A91 launch vehicle were also eventually scrapped. Since the next round of missions would require launch vehicles with much greater payload capabilities, the 8A91 was quietly retired after only two launches.
Experience gained from the 8A91 flights was not wasted and helped Korolev’s engineers iron out problems with the development of the R-7 ICBM and its derivatives. In the mean time the basic 8K71 would be modified to carry larger payloads into space in support of the next round of space spectaculars. With the relatively “easy” space firsts achieved, Khrushchev charged Korolev and his team with attaining the next goal: The first probes to the Moon (see “The First Race to the Moon: Getting Off the Ground“).
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Related Video
Here is a Universal News Reel from June 9, 1958 about the Sputnik 3 satellite:
Related Reading
“Sputnik: The Launch of the Space Age”, Drew Ex Machina, October 4, 2017 [Post]
“Sputnik 2: The First Animal in Orbit”, Drew Ex Machina, November 2, 2017 [Post]
“The First Race to the Moon: Getting Off the Ground”, Drew Ex Machina, November 8, 2018 [Post]
Bibliography
Boris Chertok, Rockets and People Volume II: Creating a Rocket Industry, NASA SP-2006-4110, 2006
James Harford, Korolev: How One Man Masterminded the Soviet Drive to Beat America to the Moon, John Wiley & Sons, 1997
John Rhea (editor), Roads to Space: An Oral History of the Soviet Space Program, Aviation Week Group, 1995
Asif A. Siddiqi, “Before Sputnik: Early Satellite Studies in The Soviet Union 1947-1957 – Part 2”, Spaceflight, pp. 389-392, Vol. 39, No. 11, November 1997
Asif A. Siddiqi, Sputnik and the Soviet Space Challenge, University Press of Florida, 2000
Timothy Varfolomeyev, “Soviet Rocketry that Conquered Space Part 1: From First ICBM to Sputnik Launcher”, Spaceflight, pp. 260-263, Vol. 37, No. 8, August 1995
Timothy Varfolomeyev, “Sputnik Era Launches”, Spaceflight, pp. 331-332, Vol. 39, No. 10, October 1997