Sputnik 1 (/ /,; "Satellite-1", or "PS-1", Простейший Спутник-1 or Prosteyshiy Sputnik-1, "Elementary Satellite-1") was the first artificial Earth satellite. It was launched into an elliptical low Earth orbit by the USSR on 4 October 1957 as part of the Soviet space program. It orbited for three weeks before its batteries died and then orbited silently for two months before it fell back into the atmosphere on 4 January 1958.
Object PS (Prosteishiy Sputnik)
|Mission type||Technology demonstration|
|Harvard designation||1957 Alpha 2|
|Mission duration||22 days (achieved)|
Ministry of Radiotechnical Industry
|Launch mass||83.6 kg (184 lb)|
|Dimensions||58 cm (23 in) diameter|
|Start of mission|
|Launch date||4 October 1957, 19:28:34 UTC|
|Launch site||Baikonur Cosmodrome, Site 1/5|
|End of mission|
|Last contact||26 October 1957|
|Decay date||4 January 1958|
|Reference system||Geocentric orbit|
|Regime||Low Earth orbit|
|Perigee altitude||215 km (134 mi)|
|Apogee altitude||939 km (583 mi)|
20.005 and 40.002 MHz
It was a polished metal sphere 58 cm (23 in) in diameter with four external radio antennas to broadcast radio pulses. Its radio signal was easily detectable by radio amateurs, and the 65° orbital inclination and duration of its orbit made its flight path cover virtually the entire inhabited Earth.
The satellite's unanticipated success precipitated the American Sputnik crisis and triggered the Space Race, part of the Cold War. The launch was the beginning of a new era of political, military, technological and scientific developments. The word "sputnik" is Russian for satellite when interpreted in an astronomical context; its other meanings are spouse or traveling companion.
Tracking and studying Sputnik 1 from Earth provided scientists with valuable information. The density of the upper atmosphere could be deduced from its drag on the orbit, and the propagation of its radio signals gave data about the ionosphere.
Sputnik 1 was launched during the International Geophysical Year from Site No.1/5, at the 5th Tyuratam range, in Kazakh SSR (now known as the Baikonur Cosmodrome). The satellite travelled at a peak speed of about 8 km/s (18,000 mph), taking 96.20 minutes to complete each orbit. It transmitted on 20.005 and 40.002 MHz, which were monitored by radio operators throughout the world. The signals continued for 21 days until the transmitter batteries ran out on 26 October 1957. Sputnik 1 burned up on 4 January 1958 while reentering Earth's atmosphere, after three months, 1,440 completed orbits of the Earth, and a distance travelled of about 7.0×107 km (4.3×107 mi).
Before the launch
Satellite construction project
On 17 December 1954, chief Soviet rocket scientist Sergei Korolev proposed a developmental plan for an artificial satellite to the Minister of the Defence Industry, Dimitri Ustinov. Korolev forwarded a report by Mikhail Tikhonravov, with an overview of similar projects abroad. Tikhonravov had emphasized that the launch of an orbital satellite was an inevitable stage in the development of rocket technology.
On 29 July 1955, U.S. President Dwight D. Eisenhower announced through his press secretary that, during the International Geophysical Year (IGY), the United States would launch an artificial satellite. Four days later, Leonid Sedov, a leading Soviet physicist, announced that they too would launch an artificial satellite. On 8 August, the Politburo of the Communist Party of the Soviet Union approved the proposal to create an artificial satellite. On 30 August Vasily Ryabikov—the head of the State Commission on the R-7 rocket test launches—held a meeting where Korolev presented calculation data for a spaceflight trajectory to the Moon. They decided to develop a three-stage version of the R-7 rocket for satellite launches.
On 30 January 1956 the Council of Ministers approved practical work on an artificial Earth-orbiting satellite. This satellite, named Object D, was planned to be completed in 1957–58; it would have a mass of 1,000 to 1,400 kg (2,200 to 3,100 lb) and would carry 200 to 300 kg (440 to 660 lb) of scientific instruments. The first test launch of "Object D" was scheduled for 1957. Work on the satellite was to be divided among institutions as follows:
- The USSR Academy of Sciences was responsible for the general scientific leadership and the supply of research instruments
- The Ministry of the Defence Industry and its primary design bureau, OKB-1, were assigned the task of building the satellite
- The Ministry of the Radiotechnical Industry would develop the control system, radio/technical instruments, and the telemetry system
- The Ministry of the Ship Building Industry would develop gyroscope devices
- The Ministry of the Machine Building would develop ground launching, refueling and transportation means
- The Ministry of the Defense was responsible for conducting launches
Preliminary design work was completed in July 1956 and the scientific tasks to be carried out by the satellite were defined. These included measuring the density of the atmosphere and its ion composition, the solar wind, magnetic fields, and cosmic rays. This data would be valuable in the creation of future artificial satellites; a system of ground stations was to be developed to collect data transmitted by the satellite, observe the satellite's orbit, and transmit commands to the satellite. Because of the limited time frame, observations were planned for only 7 to 10 days and orbit calculations were not expected to be extremely accurate.
By the end of 1956 it became clear that the complexity of the ambitious design meant that 'Object D' could not be launched in time because of difficulties creating scientific instruments and the low specific impulse produced by the completed R-7 engines (304 sec instead of the planned 309 to 310 sec). Consequently, the government rescheduled the launch for April 1958. Object D would later fly as Sputnik 3.
Fearing the U.S. would launch a satellite before the USSR, OKB-1 suggested the creation and launch of a satellite in April–May 1957, before the IGY began in July 1957. The new satellite would be simple, light (100 kg or 220 lb), and easy to construct, forgoing the complex, heavy scientific equipment in favour of a simple radio transmitter. On 15 February 1957 the Council of Ministers of the USSR approved this simple satellite, designated 'Object PS'. This version allowed the satellite to be tracked visually by Earth-based observers, and it could transmit tracking signals to ground-based receiving stations. The launch of two satellites, PS-1 and PS-2, with two R-7 rockets (8K71), was approved, provided that the R-7 completed at least two successful test flights.
Launch vehicle preparation and launch site selection
The R-7 rocket was initially designed as an intercontinental ballistic missile (ICBM) by OKB-1. The decision to build it was made by the Central Committee of the Communist Party of the Soviet Union and the Council of Ministers of the USSR on 20 May 1954. The rocket was the most powerful in the world; it was designed with excessive thrust since they were unsure how heavy the hydrogen bomb payload would be. The R-7 was also known by its GRAU (later GURVO, the Russian abbreviation for "Chief Directorate of the Rocket Forces") designation 8K71. At the time, the R-7 was known to NATO sources as the T-3 or M-104, and Type A. A special reconnaissance commission selected Tyuratam for the construction of a rocket proving ground, the 5th Tyuratam range, usually referred to as "NIIP-5", or "GIK-5" in the post-Soviet time. The selection was approved on 12 February 1955 by the Council of Ministers of the USSR, but the site would not be completed until 1958. Actual work on the construction of the site began on 20 July by military building units. On 14 June 1956, Korolev decided to adapt the R-7 rocket to the 'Object D' (Sputnik 3), that would later be replaced by the much lighter 'Object PS' (Sputnik 1).
The first launch of an R-7 rocket (8K71 No.5L) occurred on 15 May 1957. A fire began in the Blok D strap-on almost immediately at liftoff, but the booster continued flying until 98 seconds after launch when the strap-on broke away and the vehicle crashed some 400 km (250 mi) downrange. Three attempts to launch the second rocket (8K71 No.6) were made on 10–11 June, but an assembly defect prevented launch. The unsuccessful launch of the third R-7 rocket (8K71 No.7) took place on 12 July. An electrical short caused the vernier engines to put the missile into an uncontrolled roll which resulted in all of the strap-ons separating 33 seconds into the launch. The R-7 crashed about 7 km (4.3 mi) from the pad.
The launch of the fourth rocket (8K71 No.8), on 21 August at 15:25 Moscow Time, was successful. The rocket's core boosted the dummy warhead to the target altitude and velocity, reentered the atmosphere, and broke apart at a height of 10 km (6.2 mi) after traveling 6,000 km (3,700 mi). On 27 August, the TASS issued a statement on the successful launch of a long-distance multistage ICBM. The launch of the fifth R-7 rocket (8K71 No.9), on 7 September, was also successful, but the dummy was also destroyed on atmospheric re-entry, and hence needed a redesign to completely fulfill its military purpose. The rocket, however, was deemed suitable for satellite launches, and Korolev was able to convince the State Commission to allow the use of the next R-7 to launch PS-1, allowing the delay in the rocket's military exploitation to launch the PS-1 and PS-2 satellites.
On 22 September a modified R-7 rocket, named Sputnik and indexed as 8K71PS, arrived at the proving ground and preparations for the launch of PS-1 began. Compared to the military R-7 test vehicles, the mass of 8K71PS was reduced from 280 t to 272 t, its length with PS-1 was 29.167 metres (95 ft 8.3 in) and the thrust at liftoff was 3.90 MN (880,000 lbf).
PS-1 was not designed to be controlled; it could only be observed. Initial data at the launch site would be collected at six separate observatories and telegraphed to NII-4. Located back in Moscow (at Bolshevo), NII-4 was a scientific research arm of the Ministry of Defence that was dedicated to missile development. The six observatories were clustered around the launch site, with the closest situated 1 km (0.62 mi) from the launch pad.
A second, nationwide observation complex was established to track the satellite after its separation from the rocket. Called the Command-Measurement Complex, it consisted of the coordination center in NII-4 and seven distant stations situated along the line of the satellite's ground track. These tracking stations were located at Tyuratam, Sary-Shagan, Yeniseysk, Klyuchi, Yelizovo, Makat in Guryev Oblast, and Ishkup in Krasnoyarsk Krai. Stations were equipped with radar, optical instruments, and communications systems. Data from stations were transmitted by telegraphs into NII-4 where ballistics specialists calculated orbital parameters.
The observatories used a trajectory measurement system called "Tral", developed by OKB MEI (Moscow Energy Institute), by which they received and monitored data from transponders mounted on the R-7 rocket's core stage. The data was useful even after the satellite's separation from the second stage of the rocket; Sputnik's location was calculated from the data on the second stage's location which followed Sputnik at a known distance. Tracking of the booster during launch had to be accomplished through purely passive means such as visual coverage and radar detection. R-7 test launches demonstrated that the tracking cameras were only good up to an altitude of 200 km (120 mi), but radar could track it for almost 500 km (310 mi).
Outside the Soviet Union, the satellite was tracked by amateur radio operators in many countries. The booster rocket was located and tracked by the British using the Lovell Telescope at the Jodrell Bank Observatory, the only telescope in the world able to do so by radar. Canada's Newbrook Observatory was the first facility in North America to photograph Sputnik 1.
The chief constructor of Sputnik 1 at OKB-1 was Mikhail S. Khomyakov. The satellite was a 585-millimetre (23.0 in) diameter sphere, assembled from two hemispheres that were hermetically sealed with O-rings and connected by 36 bolts. It had a mass of 83.6 kilograms (184 lb). The hemispheres were 2 mm thick, and were covered with a highly polished 1 mm-thick heat shield made of an aluminium–magnesium–titanium alloy, AMG6T. The satellite carried two pairs of antennas designed by the Antenna Laboratory of OKB-1, led by Mikhail V. Krayushkin. Each antenna was made up of two whip-like parts, 2.4 and 2.9 metres (7.9 and 9.5 ft) in length, and had an almost spherical radiation pattern.
The power supply, with a mass of 51 kg (112 lb), was in the shape of an octagonal nut with the radio transmitter in its hole. It consisted of three silver-zinc batteries, developed at the All-Union Research Institute of Power Sources (VNIIT) under the leadership of Nikolai S. Lidorenko. Two of these batteries powered the radio transmitter and one powered the temperature regulation system. The batteries had an expected lifetime of two weeks, and operated for 22 days. The power supply was turned on automatically at the moment of the satellite's separation from the second stage of the rocket.
The satellite had a one-watt, 3.5 kg (7.7 lb) radio transmitting unit inside, developed by Vyacheslav I. Lappo from NII-885, the Moscow Electronics Research Institute, that worked on two frequencies, 20.005 and 40.002 MHz. Signals on the first frequency were transmitted in 0.3 s pulses (near f = 3 Hz) (under normal temperature and pressure conditions onboard), with pauses of the same duration filled by pulses on the second frequency. Analysis of the radio signals was used to gather information about the electron density of the ionosphere. Temperature and pressure were encoded in the duration of radio beeps. A temperature regulation system contained a fan, a dual thermal switch, and a control thermal switch. If the temperature inside the satellite exceeded 36 °C (97 °F), the fan was turned on; when it fell below 20 °C (68 °F), the fan was turned off by the dual thermal switch. If the temperature exceeded 50 °C (122 °F) or fell below 0 °C (32 °F), another control thermal switch was activated, changing the duration of the radio signal pulses. Sputnik 1 was filled with dry nitrogen, pressurized to 1.3 atm (130 kPa). The satellite had a barometric switch, activated if the pressure inside the satellite fell below 130 kPa, which would have indicated failure of the pressure vessel or puncture by a meteor, and would have changed the duration of radio signal impulse.
While attached to the rocket, Sputnik 1 was protected by a cone-shaped payload fairing, with a height of 80 cm (31.5 in). The fairing separated from both Sputnik and the spent R-7 second stage at the same time as the satellite was ejected. Tests of the satellite were conducted at OKB-1 under the leadership of Oleg G. Ivanovsky.
Launch and mission
The control system of the Sputnik rocket was adjusted to an intended orbit of 223 by 1,450 km (139 by 901 mi), with an orbital period of 101.5 minutes. The trajectory had been calculated earlier by Georgi Grechko, using the USSR Academy of Sciences' mainframe computer.
The Sputnik rocket was launched on 4 October 1957 at 19:28:34 UTC (5 October at the launch site ) from Site No.1 at NIIP-5. Telemetry indicated that the strap-ons separated 116 seconds into the flight and the core stage engine shutdown 295.4 seconds into the flight. At shutdown, the 7.5-tonne core stage (with PS-1 attached) had attained an altitude of 223 km (139 mi) above sea level, a velocity of 7,780 m/s (25,500 ft/s), and a velocity vector inclination to the local horizon of 0 degrees 24 minutes. This resulted in an initial orbit of 223 km (139 mi) by 950 km (590 mi), with an apogee approximately 500 km (310 mi) lower than intended, and an inclination of 65.10° and a period of 96.20 minutes.
A fuel regulator in the booster also failed around 16 seconds into launch, which resulted in excessive RP-1 consumption for most of the powered flight and the engine thrust being 4% above nominal. Core stage cutoff was intended for T+296 seconds, but the premature propellant depletion caused thrust termination to occur one second earlier when a sensor detected overspeed of the empty RP-1 turbopump. There were 375 kg (827 lb) of LOX remaining at cutoff.
At 19.9 seconds after engine cut-off, PS-1 separated from the second stage and the satellite's transmitter was activated. These signals were detected at the IP-1 station by Junior Engineer-Lieutenant V.G. Borisov, where reception of Sputnik 1's "beep-beep-beep" tones confirmed the satellite's successful deployment. Reception lasted for 2 minutes, until PS-1 fell below the horizon. The Tral telemetry system on the R-7 core stage continued to transmit and was detected on its second orbit.
The designers, engineers and technicians who developed the rocket and satellite watched the launch from the range. After the launch they drove to the mobile radio station to listen for signals from the satellite. They waited about 90 minutes to ensure that the satellite had made one orbit and was transmitting before Korolev called Soviet premier Nikita Khrushchev.
On the first orbit the Telegraph Agency of the Soviet Union (TASS) transmitted: "As result of great, intense work of scientific institutes and design bureaus the first artificial Earth satellite has been built". The R-7 core stage, with a mass of 7.5 tonnes and a length of 26 metres, also reached Earth orbit. It was a first magnitude object following behind the satellite and visible at night. Deployable reflective panels were placed on the booster in order to increase its visibility for tracking. A small highly polished sphere, the satellite was barely visible at sixth magnitude, and thus harder to follow optically. The batteries ran out on 26 October 1957, after the satellite completed 326 orbits.
Our movies and television programs in the fifties were full of the idea of going into space. What came as a surprise was that it was the Soviet Union that launched the first satellite. It is hard to recall the atmosphere of the time.
The Soviets provided details of Sputnik 1 before the launch, but few outside the Soviet Union noticed. After reviewing information publicly available before the launch, the science writer Willy Ley wrote in 1958:
If somebody tells me that he has the rockets to shoot—which we know from other sources, anyway—and tells me what he will shoot, how he will shoot it, and in general says virtually everything except for the precise date—well, what should I feel like if I'm surprised when the man shoots?
Organized through the citizen science project Operation Moonwatch, teams of visual observers at 150 stations in the United States and other countries were alerted during the night to watch for the satellite at dawn and during the evening twilight as it passed overhead. The USSR requested amateur and professional radio operators to tape record the signal being transmitted from the satellite.
News reports at the time pointed out that "anyone possessing a short wave receiver can hear the new Russian earth satellite as it hurtles over this area of the globe." Directions, provided by the American Radio Relay League, were to "Tune in 20 megacycles sharply, by the time signals, given on that frequency. Then tune to slightly higher frequencies. The 'beep, beep' sound of the satellite can be heard each time it rounds the globe." The first recording of Sputnik 1's signal was made by RCA engineers near Riverhead, Long Island. They then drove the tape recording into Manhattan for broadcast to the public over NBC radio. However, as Sputnik rose higher over the East Coast, its signal was picked up by W2AEE, the ham radio station of Columbia University. Students working in the university's FM station, WKCR, made a tape of this, and were the first to rebroadcast the Sputnik signal to the American public (or whoever could receive the FM station).
The Soviet Union agreed to transmit on frequencies that worked with the United States' existing infrastructure, but later announced the lower frequencies. Asserting that the launch "did not come as a surprise", the White House refused to comment on any military aspects. On 5 October the Naval Research Laboratory captured recordings of Sputnik 1 during four crossings over the United States. The USAF Cambridge Research Center collaborated with Bendix-Friez, Westinghouse Broadcasting, and the Smithsonian Astrophysical Observatory to obtain a video of Sputnik's rocket body crossing the pre-dawn sky of Baltimore, broadcast on 12 October by WBZ-TV in Boston.
In Britain, the media and population initially reacted with a mixture of fear for the future, but also amazement about human progress. Many newspapers and magazines heralded the arrival of the Space Age. However, when the Soviet Union launched Sputnik 2, containing the dog Laika, the media narrative returned to one of anti-communism and many people sent protests to the Russian embassy and the RSPCA.
Sputnik 1 was not immediately used for Soviet propaganda. The Soviets had kept quiet about their earlier accomplishments in rocketry, fearing that it would lead to secrets being revealed and failures being exploited by the West. When the Soviets began using Sputnik in their propaganda, they emphasized pride in the achievement of Soviet technology, arguing that it demonstrated the Soviets' superiority over the West. People were encouraged to listen to Sputnik's signals on the radio and to look out for Sputnik in the night sky. While Sputnik itself had been highly polished, its small size made it barely visible to the naked eye. What most watchers actually saw was the much more visible 26-metre core stage of the R-7. Shortly after the launch of PS-1, Khrushchev pressed Korolev to launch another satellite to coincide with the 40th anniversary of the October Revolution, on 7 November 1957.
The launch of Sputnik 1 surprised the American public, and shattered the perception created by American propaganda of the United States as the technological superpower, and the Soviet Union as a backward country. Privately, however, the CIA and President Eisenhower were aware of progress being made by the Soviets on Sputnik from secret spy plane imagery. Together with the Jet Propulsion Laboratory (JPL), the Army Ballistic Missile Agency built Explorer 1, and launched it on 31 January 1958. Before work was completed, however, the Soviet Union launched a second satellite, Sputnik 2, on 3 November 1957. Meanwhile, the televised failure of Vanguard TV3 on 6 December 1957 deepened American dismay over the country's position in the Space Race. The Americans took a more aggressive stance in the emerging space race, resulting in an emphasis on science and technological research, and reforms in many areas from the military to education systems. The federal government began investing in science, engineering, and mathematics at all levels of education. An advanced research group was assembled for military purposes. These research groups developed weapons such as ICBMs and missile defense systems, as well as spy satellites for the U.S.
On Friday, 4 October 1957, the Soviets had orbited the world's first artificial satellite. Anyone who doubted its existence could walk into the backyard just after sunset and see it.
Initially, U.S. President Eisenhower was not surprised by Sputnik 1. He had been forewarned of the R-7's capabilities by information derived from U-2 spy plane overflight photos, as well as signals and telemetry intercepts. The Eisenhower administration's first response was low-key and almost dismissive. Eisenhower was even pleased that the USSR, not the U.S., would be the first to test the waters of the still-uncertain legal status of orbital satellite overflights. Eisenhower had suffered the Soviet protests and shoot-downs of Project Genetrix (Moby Dick) balloons and was concerned about the probability of a U-2 being shot down. To set a precedent for "freedom of space" before the launch of America's secret WS-117L spy satellites, the U.S. had launched Project Vanguard as its own "civilian" satellite entry for the International Geophysical Year. Eisenhower greatly underestimated the reaction of the American public, who were shocked by the launch of Sputnik and by the televised failure of the Vanguard Test Vehicle 3 launch attempt. The sense of anxiety was inflamed by Democratic politicians and professional cold warriors, who portrayed the United States as woefully behind. One of the many books that suddenly appeared for the lay-audience noted seven points of "impact" upon the nation: Western leadership, Western strategy and tactics, missile production, applied research, basic research, education, and democratic culture.
The U.S. soon had a number of successful satellites, including Explorer 1, Project SCORE, and Courier 1B. However, public reaction to the Sputnik crisis spurred America to action in the Space Race, leading to the creation of both the Advanced Research Projects Agency (renamed the Defense Advanced Research Projects Agency, or DARPA, in 1972), and NASA (through the National Aeronautics and Space Act), as well as increased U.S. government spending on scientific research and education through the National Defense Education Act.
Sputnik also contributed directly to a new emphasis on science and technology in American schools. With a sense of urgency, Congress enacted the 1958 National Defense Education Act, which provided low-interest loans for college tuition to students majoring in maths and science. After the launch of Sputnik, a poll conducted and published by the University of Michigan showed that 26% of Americans surveyed thought that Russian sciences and engineering were superior to that of the United States. (A year later, however, that figure had dropped to 10% as the U.S. began launching its own satellites into space.)
One irony of the Sputnik event was the initially low-key response of the Soviet Union. The Communist Party newspaper Pravda only printed a few paragraphs about Sputnik 1 on 4 October.
Sputnik also inspired a generation of engineers and scientists. Harrison Storms, the North American designer who was responsible for the X-15 rocket plane, and went on to head the effort to design the Apollo command and service module and Saturn V launch vehicle's second stage, was moved by the launch of Sputnik to think of space as being the next step for America. Astronauts Alan Shepard (who was the first American in space) and Deke Slayton later wrote of how the sight of Sputnik 1 passing overhead inspired them to their new careers.
The launch of Sputnik 1 led to the resurgence of the suffix -nik in the English language. The American writer Herb Caen was inspired to coin the term "beatnik" in an article about the Beat Generation in the San Francisco Chronicle on 2 April 1958.
Backup units and replicas
At least two vintage duplicates of Sputnik 1 exist, built apparently as backup units. One resides just outside Moscow in the corporate museum of Energia, the modern descendant of Korolev's design bureau, where it is on display by appointment only. Another is in the Museum of Flight in Seattle, Washington. Unlike Energia's unit, it has no internal components, but it does have casings and molded fittings inside (as well as evidence of battery wear), which suggests[according to whom?] it was built as more than just a model. Authenticated by the Memorial Museum of Cosmonautics in Moscow, the unit was auctioned in 2001 and purchased by an anonymous private buyer, who donated it to the museum. Two more Sputnik backups are said to be in the personal collections of American entrepreneurs Richard Garriott and Jay S. Walker.
In 1959, the Soviet Union donated a replica of Sputnik to the United Nations. There are other full-size Sputnik replicas (with varying degrees of accuracy) on display in locations around the world, including the National Air and Space Museum in the US, the Science Museum in the United Kingdom, the Powerhouse Museum in Australia, and outside the Russian embassy in Spain.
Three one-third scale student-built replicas of Sputnik 1 were deployed from the Mir space station between 1997 and 1999. The first, named Sputnik 40 to commemorate the fortieth anniversary of the launch of Sputnik 1, was deployed in November 1997. Sputnik 41 was launched a year later, and Sputnik 99 was deployed in February 1999. A fourth replica was launched, but never deployed, and was destroyed when Mir was deorbited.
The Sputnik 1 EMC/EMI is a class of full-scale laboratory models of the satellite. The models, manufactured by OKB-1 and NII-885 (headed by Mikhail Ryazansky), were introduced on February 15, 1957. They were made to test ground electromagnetic compatibility (EMC) and electromagnetic interference (EMI).
The launch of Sputnik also planted the seeds for the development of modern satellite navigation. Two American physicists, William Guier and George Weiffenbach, at Johns Hopkins University's Applied Physics Laboratory (APL) decided to monitor Sputnik's radio transmissions and within hours realized that, because of the Doppler effect, they could pinpoint where the satellite was along its orbit. The Director of the APL gave them access to their UNIVAC to do the heavy calculations required.
Early the next year, Frank McClure, the deputy director of the APL, asked Guier and Weiffenbach to investigate the inverse problem: pinpointing the user's location, given the satellite's. At the time, the Navy was developing the submarine-launched Polaris missile, which required them to know the submarine's location. This led them and APL to develop the TRANSIT system, a forerunner of modern Global Positioning System (GPS) satellites.
- Donald B. Gillies – one of the first to calculate the Sputnik 1 orbit
- ILLIAC I – first computer to calculate the orbit of Sputnik 1
- Kerim Kerimov – one of the lead architects behind Sputnik 1
- Timeline of artificial satellites and space probes
- Timeline of Russian innovation
- Yuri Gagarin – Soviet cosmonaut and first human to journey into outer space
- Valentina Tereshkova, first woman in space
- "Sputnik 1 (PS-1 #1)". Gunter's Space Page. 11 December 2017. Retrieved 16 May 2021.
- Zak, Anatoly (2015). "Sputnik's mission". RussianSpaceWeb.com. Archived from the original on 23 January 2013. Retrieved 27 December 2015.
- "Sputnik 1". Encyclopedia Astronautica. Archived from the original on 27 December 2016. Retrieved 8 January 2017.
- "Trajectory: Sputnik-1 1957-001B". NASA. 27 April 2021. Retrieved 16 May 2021. This article incorporates text from this source, which is in the public domain.
- Siddiqi, p. 155.
- Terry 2013, p. 233.
- Ralph H. Didlake, KK5PM; Oleg P. Odinets, RA3DNC (28 September 2007). "Sputnik and Amateur Radio". American Radio Relay League. Archived from the original on 11 October 2007. Retrieved 26 March 2008.
- McDougall, Walter A. (Winter 2010). "Shooting The Moon". American Heritage. 59 (4). ISSN 0002-8738. Retrieved 3 January 2019.
- Swenson, et al, p. 71
- "Display: Sputnik-1 1957-001B". NASA. 27 April 2021. Retrieved 16 May 2021. This article incorporates text from this source, which is in the public domain.
- "Sputnik 1, Earth's First Artificial Satellite in Photos". SPACE.com.
- "APOD: October 3, 1998 – Sputnik: Traveling Companion". apod.nasa.gov. This article incorporates text from this source, which is in the public domain.
- Jorden, William J. (5 October 1957). "Soviet Fires Earth Satellite Into Space". The New York Times. Retrieved 28 December 2015.
- "Sputnik-1 1957-001B". NASA. 27 April 2021. Retrieved 16 May 2021. This article incorporates text from this source, which is in the public domain.
- Korolev, Sergei (26 May 1954). "On the possibility of Earth's artificial satellite development" (in Russian). Archived from the original on 8 April 2008. Retrieved 26 March 2008.
- Создание первых искусственных спутников Земли. Начало изучения Луны. Спутники "Зенит" и "Электрон", book: Гудилин В.Е., Слабкий Л.И.(Слабкий Л.И.)(Gudilin V., Slabkiy L.)"Ракетно-космические системы (История. Развитие. Перспективы)",М.,1996 Archived 14 March 2007 at the Wayback Machine (in Russian)
- "Korolev and Freedom of Space: 14 February 1990 – 4 October 1957". NASA. Archived from the original on 7 October 2006. Retrieved 18 February 2007.
- The Presidium of the Central Committee of the CPSU (8 August 1955). "On the creation of the Earth's artificial satellite" (in Russian). Archived from the original on 8 April 2008. Retrieved 26 March 2008.
- "G. S. Vetrov, Korolev And His Job. Appendix 2" (in Russian). Archived from the original on 7 March 2008. Retrieved 26 March 2008.
- "Sputnik Arming Key in Space Race". Smithsonian National Air and Space Museum. Retrieved 13 July 2019.
- "The Beginning" (in Russian). Archived from the original on 27 September 2007. Retrieved 26 March 2008.
- Lidorenko, Nikolai. "On the Launch of the First Earth's artificial satellite in the USSR" (in Russian). Archived from the original on 2 April 2008. Retrieved 26 March 2008.
- "40 Years of Space Era" (in Russian). Archived from the original on 29 February 2008. Retrieved 26 March 2008.
- Lanius, et al, p. 38.
- Lafleur, Claude (2004). "Spacecrafts [sic] launched in 1957". ClaudeLafleur.qc.ca. Archived from the original on 27 August 2011. Retrieved 26 March 2008.
- "Межконтинентальная баллистическая ракета Р-7" [Intercontinental ballistic missile R-7] (in Russian). Arms.ru. Archived from the original on 7 March 2012. Retrieved 10 January 2013.
- Isachenkov, Vladimir (30 September 2007). "Sputnik at 50: An improvised triumph". USA Today. Associated Press. Retrieved 13 July 2019.
- Zaloga, p. 232.
- Cox & Stoiko, p. 69.
- Bilstein, p. 387.
- Zak, Anatoly (2015). "Origin of the test range in Tyuratam". RussianSpaceWeb.com. Archived from the original on 23 November 2015. Retrieved 27 December 2015.
- Zak, Anatoly. "Sputnik-3". RussianSpaceWeb.com. Archived from the original on 5 October 2007.
- Lanius, et al, p. 38
- Wade, Mark. "R-7". Encyclopedia Astronautica. Archived from the original on 29 June 2011.
- "S.P.Korolev RSC Energia – Launchers". www.energia.ru. Archived from the original on 9 January 2017. Retrieved 4 October 2007.
- Zak, Anatoly. "R-7 family of launchers and ICBMs". RussianSpaceWeb.com. Archived from the original on 4 October 2007.
- Harford, p. 127.
- V.Poroshkov. Создание и запуск Первого спутника Земли [Creation and Launch of the First Earth's Satellite] (in Russian). Novosti Kosmonavtiki. Archived from the original on 6 June 2011.
- V.Poroshkov. Создание и запуск Первого спутника Земли [Creation and Launch of the First Earth's Satellite] (in Russian). Novosti Kosmonavtiki. Archived from the original on 6 June 2011. Retrieved 10 January 2013.
- Siddiqi, p. 163.
- 45th Anniversary of the First Start of Native ICBM R-7 Archived 8 January 2009 at the Wayback Machine at Ukrainian Aerospace Portal (in Russian)
- Zak, Anatoly. "Sputnik launch vehicle 8K71PS (M1-1PS)". RussianSpaceWeb.com. Archived from the original on 11 December 2015. Retrieved 4 October 2007.
- Siddiqi, p. 39.
- Siddiqi, p. 162.
- ИСТОРИЯ ЦУПА: ТРУД, РАДОСТИ, МЫТАРСТВА [HISTORY OF DECORATION: LABOR, JOY, TREATMENT] (in Russian). НАУКА и ЖИЗНЬ. Archived from the original on 18 June 2008.
- Wonderful "Seven" and First Satellites at the website of OKB MEI Archived 3 September 2007 at the Wayback Machine
- Yu.A.Mozzhorin Memories Archived 18 October 2007 at the Wayback Machine at the website of Russian state archive for scientific-technical documentation(in Russian)
- Lovell, p. 196.
- Canadian Register of Historic Places (2015). "Newbrook Observatory". Historicplaces.ca. Canada's Historic Places. Archived from the original on 30 October 2012. Retrieved 29 December 2015.
- Олегу Генриховичу Ивановскому – 80 лет [80th Anniversary of Oleg Genrikhovich Ivanovsky] (in Russian). Novosti Kosmonavtiki. Archived from the original on 19 June 2009.
- Кречетников, Артем. Старт космической эры [Start of the Space Era] (in Russian). BBC Russia. Archived from the original on 5 February 2008.
- Wade, Mark. "Sputnik 1". Encyclopedia Astronautica. Archived from the original on 2 February 2007. Retrieved 20 January 2007.
- ПС-1 – первый искусственный спутник Земли [PS-1 – Earth's First Artificial Satellite] (in Russian). Novosti Kosmonatviki. Archived from the original on 11 October 2007.
- Спутник, спасший мир [The companion who saved the world] (in Russian). Парламентская газета. 4 October 2007. Archived from the original on 19 December 2007.
- ИСЗ Спутник-1 [Sputnik-1 Satellite] (in Russian). USSR in space. 27 June 2018. Archived from the original on 23 March 2008.
- Golovanov, Yaroslav K. (2007). "57: Space". Королев: факты и мифы [Korolev: Facts and myths] (in Russian). Moscow: Russian Knights Foundation. ISBN 9785903389018. Archived from the original on 9 January 2009. Retrieved 12 January 2019.
- Anatoly Zak (2017). "Design of the first artificial satellite of the Earth". RussianSpaceWeb.com. Retrieved 1 January 2021.
- "Moskva Electronics Research Institute Novaya NII 885" (PDF). National Photographic Interpretation Center. May 1970. Archived (PDF) from the original on 23 September 2017.
- Form of Signals of the First Earth's Artificial Satellite Archived 25 October 2007 at the Wayback Machine – a document at the website of Russian state archive for scientific-technical documentation
- Main Results of the Launch of the Rocket with the First ISZ Onboard on 4 October 1957 Archived 2 October 2007 at the Wayback Machine – document signed by S.P. Korolev, V.P. Glushko, N.A. Pilyugin and V.P. Barmin, in the book by Vetrov "Korolev and His Job" (in Russian)
- Siddiqi, p. 154.
- "Sputnik 1" (in Spanish). Archived from the original on 27 September 2007.
- How the First Sputnik Was Launched Archived 8 April 2008 at the Wayback Machine at Zemlya i Vselennaya magazine, No.5, 2002 (in Russian)
- "World's first satellite and the international community's response". VoR.ru. Archived from the original on 12 September 2007. Retrieved 22 January 2007.
- Brzezinski, pp. 158–159
- Спутник-1 – начало космической эры (in Russian). Rustrana.ru. 21 July 2005. Archived from the original on 29 September 2007. Retrieved 4 October 2007.
- "Reds Say Sputnik's Batteries Worn Out". Argus-Leader. Sioux Falls, South Dakota. Associated Press. 26 October 1957. p. 1 – via Newspapers.com.
- David, Leonard (4 October 2002). "Sputnik 1: The Satellite That Started It All". Space.com. Archived from the original on 16 February 2006. Retrieved 20 January 2007.
- Ley, Willy (October 1958). "How Secret was Sputnik No. 1?". Galaxy. pp. 48–50. Retrieved 13 June 2014.
- Sullivan, Walter (5 October 1957). "Course Recorded". The New York Times.
- Ackman, p. 280.
- Greg Messel (2012). Last of the Seals. BookBaby. p. 131. ISBN 978-0-9854859-1-7.
- "How To Tune," San Antonio Light, 5 October 1957, p1
- "Senators Attack Missile Fund Cut". The New York Times. 6 October 1957. Retrieved 20 January 2007.
- Ted Molczan, "Motion Picture of Sputnik 1 Rocket from Baltimore on October 12, 1957" Archived 29 October 2013 at the Wayback Machine, 30 June 2013.
- "Reaction to the Soviet Satellite: A Preliminary Evaluation" (PDF). White House Office of the Staff Research Group. 16 October 1957. Box 35, Special Projects: Sputnik, Missiles and Related Matters; NAID #12082706. Archived (PDF) from the original on 24 December 2016. Retrieved 28 April 2015 – via The Eisenhower Presidential Library.
- "ARPA/DARPA". Defense Advanced Research Projects Agency. Archived from the original on 7 April 2007. Retrieved 21 May 2007.
- "DARPA: History". Defense Advanced Research Projects Agency. Archived from the original on 15 October 2009. Retrieved 7 December 2009.
- "Roads and Crossroads of Internet History" Archived 27 January 2016 at the Wayback Machine by Gregory Gromov
- Green, pp. 186–187
- Nicholas Barnett '"Russia Wins Space Race"': The British Press and the Sputnik Moment, 1957': Media History, 19: 2 (2013), 182–195
- Bessonov, K. (2007). Sputnik's legacy. Moscow News, 41. Retrieved from "Archived copy". Archived from the original on 26 May 2009. Retrieved 29 October 2009.CS1 maint: archived copy as title (link).
- Siddiqi, p. 172.
- West, John B. (30 January 2015). "Historical Aspects of Early Soviet/Russian Manned Space Program". Essays on the History of Respiratory Physiology. Springer. pp. 334–35. ISBN 978-1-4939-2362-5.
- The Legacy of Sputnik [Editorial]. (2007). The New York Times, p. 28.
- "Sputnik Declassified". NOVA. Season 34. Episode 15. 6 November 2007.
- Wilson, C. (n.d.). Sputnik: a Mixed Legacy. U.S. News & World Report, 143(12), (37–38).
- Morring, F. (2007). "March). Down To Earth". Aviation Week and Space Technology. 166 (12): 129.
- Peoples, C. (2008). "Sputnik and 'skill thinking' revisited: technological determinism in American responses to the Soviet missile threat". Cold War History. 8 (1): 55–75. doi:10.1080/14682740701791334. S2CID 154436145.
- Gray, p. 31.
- Lashmar, p. 146.
- Peebles (2000), p. 168.
- Divine, p. xiv.
- McDougall, p. 134.
- Peebles (1991), p. 180.
- Burrows, p. 236.
- Peebles (1997), p. 26.
- McDougall, p. 118.
- Divine, p. xv.
- Brzezinski, p. 274.
- McDougall, p. 172.
- Abramson, Larry (30 September 2007). "Sputnik Left Legacy for U.S. Science Education". NPR. Retrieved 3 February 2019.
- Zhao, p. 22.
- Neal, et al, pp. 3–4.
- Project Mercury: Main-in-Space Program of NASA, Report of the Committee on Aeronautical Sciences, United States Senate, 1 December 1959
- Prados, p. 80.
- Harford, p. 121.
- Gray, p. 41.
- Shepard & Slayton, p. 43.
- Štekauer, Pavol (2000). English Word-formation: A History of Research, 1960–1995. Gunter Narr Verlag. p. 109. ISBN 978-3-8233-5210-5.
- Steinmetz, Sol (2 July 2001). Yiddish & English: The Story of Yiddish in America. University of Alabama Press. p. 65. ISBN 978-0-8173-1103-2.
- Hamlin, Jesse (26 November 1995). "How Herb Caen Named a Generation". San Francisco Chronicle. Archived from the original on 19 January 2008. Retrieved 30 September 2007.
- "Kaluga city (Kaluga Region, Russia)". www.crwflags.com. Archived from the original on 12 March 2016. Retrieved 7 December 2018.
- "The Top Ten Sputniks". Collectspace.com. collectSPACE. 2016. Archived from the original on 21 February 2016. Retrieved 28 February 2016.
- "Energia Museum". Npointercos.jp. NPO InterCoS. 2016. Archived from the original on 15 March 2016. Retrieved 28 February 2016.
- Levy, Steven (22 September 2008). "Browse the Artifacts of Geek History in Jay Walker's Library". Wired. Archived from the original on 28 December 2013. Retrieved 28 February 2016.
- Photo/MB, UN (1 December 1959). "UN Visitors View Model of USSR Sputnik". UN Multimedia. Archived from the original on 23 September 2017. Retrieved 23 September 2017.
- "Replica Sputnik I satellite". Science Museum Group. Retrieved 3 February 2019.
- "Replica of the Sputnik-1 Satellite". Museum of Applied Arts and Sciences. Retrieved 3 February 2019.
- Stradling, Richard (17 November 1997). "Russians Launch Sputnik replica, Trigger Memories of First Satellite". Daily Record. Morristown, New Jersey. p. 6 – via Newspapers.com.
- Krebs, Gunter. "Sputnik 40, 41, 99 (RS 17, 18, 19)". Gunter's Space Page. Archived from the original on 3 March 2016. Retrieved 28 February 2016.
- "Preparations for Sputnik launch". www.russianspaceweb.com. Retrieved 23 November 2020.
- Guier, William H.; Weiffenbach, George C. (1997). "Genesis of Satellite Navigation" (PDF). Johns Hopkins APL Technical Digest. 19 (1): 178–181. Archived from the original (PDF) on 12 May 2012. Retrieved 9 April 2012.
- Steven Johnson (2010). Where good ideas come from, the natural history of innovation. New York: Riverhead Books.
- Ackmann, Martha (2004). The Mercury 13: The True Story of Thirteen Women and the Dream of Space Flight. New York: Random House. ISBN 978-0-375-75893-5.
- Bilstein, Roger E. (1980). Stages to Saturn: A Technological History of the Apollo/Saturn Launch Vehicles. Washington, DC: National Aeronautics and Space Administration. OCLC 5891638.
- Brzezinski, Matthew B. (2007). Red Moon Rising: Sputnik and the Hidden Rivalries That Ignited the Space Age. New York: Henry Holt and Co. ISBN 978-0-8050-8147-3.
- Burrows, William E. (2001). By Any Means Necessary: America's Secret Air War in the Cold War. New York: Farrar, Straus & Giroux. ISBN 978-0-374-11747-4.
- Cox, Donald; Stoiko, Michael (1958). Spacepower: What It Means To You. Philadelphia, PA: The John C. Winston Company. OCLC 2641757.
- Divine, Robert A. (1993). The Sputnik Challenge. New York: Oxford University Press. ISBN 978-0-19-505008-0.
- Golovanov, Yaroslav (1994). Королев: факты и мифы [Korolev: Facts and Myths] (in Russian). Moscow: Nauka. ISBN 978-5-02-000822-9.
- Gray, Mike (1992). Angle of Attack: Harrison Storms and the Race to the Moon. New York: W. W. Norton & Co. ISBN 978-0-393-01892-9.
- Green, Constance McLaughlin (1970). Vanguard: A History (PDF). NASA Historical Series. Washington, DC: National Aeronautics and Space Administration. OCLC 204635. SP-4202.
- Harford, James J. (1997). Korolev: How One Man Masterminded the Soviet Drive to Beat America to the Moon. New York: John Wiley & Sons. ISBN 978-0-471-14853-1.
- Lanius, Roger D.; Logsdon, John M.; Smith, Robert W. (2013). Reconsidering Sputnik: Forty Years Since the Soviet Satellite. London: Routledge. ISBN 978-1-134-96033-0.
- Lashmar, Paul (1996). Spy Flights of the Cold War. Annapolis, MD: U.S. Naval Institute Press. ISBN 978-1-55750-837-9.
- Lovell, Bernard (1968). The Story of Jodrell Bank. New York: Harper & Row. OCLC 439766.
- McDougall, Walter A. (1985). ...The Heavens and the Earth: A Political History of the Space Age. New York: Basic Books. ISBN 978-0-465-02887-0.
- Neal, Homer A.; Smith, Tobin L.; McCormick, Jennifer B. (2008). Beyond Sputnik: U.S. Science Policy in the Twenty-first Century. Ann Arbor: University of Michigan Press. ISBN 978-0-472-11441-2.
- Peebles, Curtis (1991). The Moby Dick Project: Reconnaissance Balloons Over Russia. Washington, DC: Smithsonian Institution Press. ISBN 978-1-56098-025-4.
- Peebles, Curtis (1997). The Corona Project: America's First Spy Satellites. Annapolis, MD: U.S. Naval Institute Press. ISBN 978-1-55750-688-7.
- Peebles, Curtis (2000). Shadow Flight: America's Secret Air War Against the Soviet Union. Novato, CA: Presideo Press. ISBN 978-0-89141-700-2.
- Prados, John (1982). The Soviet Estimate: U.S. Intelligence Analysis & Russian Military Strength. New York: Dial Press. ISBN 978-0-385-27211-7.
- Shepard, Alan B.; Slayton, Donald K. (1994). Moon Shot: The Inside Story of America's Race to the Moon. Atlanta, GA: Turner Publishing. ISBN 978-1-57036-167-8.
- Siddiqi, Asif A. (2003). Sputnik and the Soviet Space Challenge. Gainesville, FL: University of Florida Press. ISBN 978-0-8130-2627-5.
- Swenson, Loyd S.; Grimwood, James M.; Alexander, Charles C. (1966). This New Ocean: A History of Project Mercury. Washington, DC: National Aeronautics and Space Administration. OCLC 569889.
- Terry, Paul (2013), Top 10 Of Everything, Octopus Publishing Group Ltd 2013, ISBN 978-0-600-62887-3
- Zaloga, Steven J. (2002). The Kremlin's Nuclear Sword: The Rise and Fall of Russia's Strategic Nuclear Forces, 1945–2000. Washington, DC: Smithsonian Institution Press. ISBN 978-1-58834-007-8.
- Zhao, Yong (2009). Catching Up Or Leading the Way: American Education in the Age of Globalization. ASCD. ISBN 978-1-4166-0873-8.
- Chertok, B. E. (1999). Rakety i li︠u︡di: lunnai︠a︡ gonka [Rockets & People: The Moon Race] (in Russian). Moscow: Mashinostroenie. ISBN 978-5-217-02942-6.
- Dickson, Paul (2007). Sputnik: The Shock of the Century. Walker & Co. ISBN 978-0-8027-1365-0.
- Gerchik, Konstantin Vasilyevich (1994). Proryv v kosmos [A Breakthrough in Space] (in Russian). Moscow: Veles. ISBN 978-5-87955-001-6.
- Mieczkowski, Yanek (2013). Eisenhower's Sputnik Moment: The Race for Space and World Prestige. Ithaca, NY: Cornell University Press. ISBN 978-0-8014-6793-6.