| Korolev's R-7 "Semiorka"
rocket, similar to the one that
launched the Sputniks.
The USSR also announced its intention of launching artificial Earth satellites during the IGY, but the US and its allies did not take that announcement seriously. They were unaware of the long development of Russian long-distance rockets, leading to Korolev's R7 rocket, the Semiorka ("little number seven"), a huge vehicle powered by 20 rocket engines. It was not only a very effective launcher, but also rather beautiful to behold: four tapered first-stage rockets, each with a cluster of 4 engines, surrounding the main vehicle which was powered by a cluster of its own.
On October 4, 1957, that rocket inserted the first USSR "sputnik" (= satellite) into a circular orbit above the atmosphere, causing a great commotion throughout the world. Sputnik was seen as a challenge to the US technology, as well as evidence of Soviet missiles with intercontinental range. Not only did the US hurry up its own launch plans, but it reassessed the science education program of its schools and other underpinnings of advanced technology. A month later the USSR launched Sputnik 2, which carried a dog named Laika, proving that living beings could fly into space and survive.
The US tried but failed to launch its Vanguard satellite on December 6, 1957. The margin of extra lifting power of the Vanguard's first stage was rather small, and in the critical first seconds it did not rise fast enough to safely lift the rocket off the pad; instead the rocket toppled and burned. Today all space launches employ clamps to hold the rocket down during those seconds, until full thrust is achieved; if you ever watch the countdown of a spaceflight launch, you might note that "ignition" comes a short instant before "lift-off. " It wasn't so in the early days. Later launches of "Vanguard" lifted off successfully, but it was the 1957 failure that is remembered.
Explorers 1 and 3
| Launch of Explorer 1
In view of the success of Sputnik and the failure of Vanguard, Von Braun's launch plan was given the go-ahead, and on January 31, 1958, it orbited the first successful US satellite, Explorer 1 (launch picture on right). Aboard it was Van Allen's Geiger counter, and a similar spacecraft, Explorer 3, followed it in March (Explorer 2 failed).
Van Allen had planned to observe the cosmic radiation, high-speed ions (atoms stripped of electrons) from the distant universe. In particular, it sought to measure the flow of cosmic ray ions of the lowest energies, which are completely absorbed by the atmosphere and therefore cannot be studied from the ground (later Sampex mission studied such particles, with much better instruments). Unlike the orbits of the Sputniks, that of Explorer 1 was quite elliptic, rising to altitudes above 2000 km.
At the higher altitudes, strangely, the rate of cosmic ray particles recorded by the Geiger counter dropped to zero. The reason was found by Explorer 3, which showed that at the higher elevation the actual radiation was so high that the instrument became overloaded. This way was discovered the belt of "trapped radiation" (that is, of trapped ions and electrons) extending around the Earth, held by the Earth's magnetic field.
More of the story of the discovery of the radiation belt is told here, part of an extensive overview "The Exploration of the Earth's Magnetosphere."
The method of rocket firing from balloons is still used by amateurs today.
Web site on Sputnik 1.
On the life and work of Sergei Korolev.
About Korolev's role in launching Sputnik.
Site links collected by the NASA History Office.
3 books on the history of spaceflight:
"Countdown: A History of Spaceflight" by T. A. Heppenheimer, 398 pp., Wiley 1997.
"Korolev: How One Man masterminded the Soviet Drive to Beat America to the Moon", by James Harford, 292 pp. Wiley, 1997.
(Also reviewed by Alan Wells in New Scientist, 19 July 1997, p.44)
Something New Under the Sun: "Satellites and the Beginnings of the Space Age" Helen Gavaghan, 300 pp. , Copernicus, 1998.
A superb sourcebook on all aspects of spaceflight--history, vehicles, missions, etc.: "The Cambridge Encyclopedia of Space" edited by Michael Rycroft, Univ. of Cambridge Press, 1990. Related book in French: "Le Gran Atlas de l'Espace," Encyclopaedia Universalis, 1989.
Blazing the Trail, the Early History of Spacecraft and Rocketry, by Michael Gruntman, 503pp, published by AIAA (Amer. Institute of Aeronautics and Astronautics), 2004.
A historical overview with many unique photographs and stories. See AIAA Bookstore at http://www.aiaa.org.
Questions from Users:
What is the radiation hazard in space?
Van Allen belts and Spaceflight.