Navigation in Space
Navigation in space can be said to have begun on October 4, 1957. Great transformations in human history often have debatable origins, but that date marks the defining moment when man took a first step to escape the “surly bonds of earth”; it was the beginning of the space age. On that date an aluminum ball about 58 cm in diameter called Sputnik (Russian for satellite) was successfully rocketed beyond the earth’s atmosphere and into a low orbit circling the earth every 96 min. With a mass of only about 83 kg it was placed in a 700 km elliptical orbit with an eccentricity of ε = 0.05 and an inclination of 65°. As significant as this was as a demonstration of human accomplishment, the reality is that it was not initially prompted by some noble desire to advance human knowledge, but really was a by-product of military rocketry and ICBM development; the same can be said of the early US efforts in space. In fact although Goddard and other “rocket boys” did pioneering work in rocketry, it was the German V2 rocket development during World War II by young geniuses such as Wernher von Braun that made possible the sending of a Sputnik, and later the American Explorer I satellites into orbit. Be that as it may, the timing of the event was prompted by the International Council of Scientific Unions’ resolution to call for the launching of artificial satellites to mark the International Geophysical Year (IGY). The Russian success sparked immediate reaction in the USA, resulting in intense rivalry dubbed the space race between the two cold war antagonists: the USA and the Soviet Union. One month after Sputnik 1 the Soviet Union successfully launched a much larger spacecraft designated Sputnik 2 which carried a dog on board; this was the second in a series that would be continued up to Sputnik 22. The first US satellite to be successfully placed in earth orbit was named Explorer 1 and was launched in January, 1958. In April 1961 the U.S.S.R successfully placed in orbit the satellite Vostok (Russian for East) with a human on board, Yuri Gagarin; 1 month later the American astronaut Alan Sheppard was sent aloft into a suborbital path aboard a craft named Freedom 7. It was not until a year later that John Glenn orbited the earth aboard the US spacecraft named Mercury Friendship. The culmination of the US manned flight program was the landing on the moon July 20, 1969, still in the decade of the 1960s, the target that US president John F. Kennedy had exhorted the nation to achieve. On that date the world watched on television Neil Armstrong and Edwin (“Buzz”) Aldrin step out of their Apollo 11 lunar module onto the moon’s surface, while Michael Collins circled the moon in his spacecraft the Columbia.
KeywordsCircular Orbit Inertial Measurement Unit Lunar Surface Onboard Computer Deep Space Network
- 1.N. A. Armstrong, M. Collins, E. E. Aldrin, http://history.nasa.gov/alsj/a11/A11_MissionReport.pdf
- 2.R. Wheeler, Apollo Flight J., http://history.nasa.gov/afj/launchwindow/lw1.html