Vanguard project
Vanguard (Eng. "Vanguard") was a project of the civil research facility Naval Research Laboratory of the United States Navy , with the aim of putting the first American satellite into orbit . This goal was not achieved for various reasons.
The name Vanguard was used for the launch vehicle (test vehicle, abbreviation TV-x, where the x stood for the start number) and the three successful satellites.
The history
US President Dwight D. Eisenhower announced on July 29, 1955, through White House Spokesman James Hagerty , that as the United States' national contribution to the International Geophysical Year (July 1, 1957 to December 31, 1958), he would place an Earth satellite in Order. Eisenhower wanted to emphasize the civil character of space research and thus defuse the question of overflight rights over other states. In times of the Cold War this was of course a challenge to the Soviet Union , which four days later also announced that it wanted to launch a satellite. The Soviets finally managed to make Sputnik 1, the first satellite, orbit the earth on October 4, 1957 .
At the time, NASA , later founded by Eisenhower, did not exist, and so there were three competing projects:
- a project of the Air Force ( US Air Force ), based on the at that time not yet existing Atlas - intercontinental ballistic missile .
- a project of the US Army ( US Army ), led by Wernher von Braun , the inside of the US Army, the Jupiter-C - launcher developed (in Huntsville's Redstone Arsenal , Alabama) and had experience in this field.
- Project Vanguard, led by John P. Hagen , a new missile from the Naval Research Laboratory of the US Navy.
As a prerequisite for a project for the International Geophysical Year, the USA envisaged a civil project or the lowest possible military participation in order to keep possible differences with the Soviet Union small. For reasons of confidentiality, too, a missile project from military research should not be used for research purposes, because the American scientists wanted to keep their projects as open as possible for those involved in all nations and to provide as much information as possible. This led to the choice of the Vanguard project, for which the rocket technology had to be largely redeveloped within a short period of time. The planned missile type was significantly more complicated than the technology of the Jupiter-C launcher, which was based on a modified medium-range missile of the Redstone type .
The rocket
The three-stage American launch vehicle was developed on the basis of the Viking sounding rocket . Compared to the Redstone, it was significantly slimmer. The first stage, built by General Electric , was powered by a mixture of kerosene and oxygen. The second stage engine was similar to that of the Navy's Aerobee sounding rocket and operated on a mixture of nitric acid and unsymmetrical dimethylhydrazine . This stage contained the missile's control systems. The third and top stage was a solid rocket made by the Grand Central Rocket Company, which, when the second stage was separated, was rotated about its longitudinal axis for stabilization. It was used from 1957 and achieved negative fame for its susceptibility to errors (9 false starts in 12 missions).
Technical specifications:
- Total mass: 10.5 t
- Payload: 40 kg
- Height: 21.95 m
- Max. Diameter: 1.14 m
- Starting thrust: 120 kN
The satellites
The small, spherical satellite Vanguard 1 , which with a diameter of 16.5 cm has a mass of about 1.47 kg, was also jokingly called grapefruit by Khrushchev . It was the second satellite successfully put into orbit in the USA after Explorer 1 and the first satellite to be equipped with solar cells . Thanks to this energy source, it was possible for seven years, until 1964, to follow its trajectory using the signals it sent and to derive knowledge about the shape of the earth from it.
It reached an orbit between 654 and 3969 km altitude at a 34.25 ° orbit inclination.
The radiation pressure caused Vanguard 1 to be displaced 1,600 m from its orbit within 28 months. Even after more than 60 years, however, it is still in a stable orbit, which it is expected to maintain for another 240 years before the crash.
Starts
- Dec. 06, 1957 - First attempt (Vanguard TV 3) of the complete launcher. Two seconds after taking off, the first step explodes and the upper steps collapse. The satellite survives the explosion. In the American press, following the Soviet Sputnik, terms such as Flopnik, Goofnik, Kaputnik, Nullnik, Oopsnik, Stallnik or Stayputnik are used for the flopped start attempt .
- February 5, 1958 - Situation control fails after 57 seconds. The aerodynamic forces that occur lead to structural failure of the launcher.
- Mar. 17, 1958 - Launch of the Vanguard 1 satellite on board a three-stage launcher (code TV-4).
- Apr. 28, 1958 - Second stage electrical failure, preventing third stage from igniting.
- May 27, 1958 - Attitude control problems prevent reaching an orbit.
- June 26, 1958 - The second stage switches off again after eight seconds, so the third stage is not ignited.
- September 26, 1958 - Second stage did not perform well.
- Feb. 17, 1959 - Vanguard 2 satellite placed in orbit with a mass of around 10 kg.
- April 13, 1959 - Position control of the second stage is lost when the first stage is separated.
- Jun. 22, 1959 - Loss of pressure in the tanks after ignition of the second stage.
- Sep. 18, 1959 - Vanguard 3 satellite placed in orbit with a mass of 22.7 kg. However, the third stage did not separate from the satellite as planned.
literature
- Horst Stöcker (Ed.): Pocket book of physics. Formulas, tables, overviews. 3rd, completely revised and expanded edition. German, Thun u. a. 1998, ISBN 3-8171-1556-3 .
Web links
- The Juno and Vanguard rockets on Bernd-Leitenberger's website
- Vanguard: A History (NASA History Series, English)
- all flights as part of the Vanguard project (English)
- Web Archive: Essay on the general conditions of the project ( Memento from July 25, 2008 in the Internet Archive )
- The Vanguard with its versions in Gunter's Space Page (English)
Individual evidence
- ↑ a b Korolev and Freedom of Space: February 14, 1955 – October 4, 1957 at www.hq.nasa.gov , accessed September 1, 2016
- ^ A b Sparrow, Giles., Evening, Bernhard ,: Adventure space travel: [50 years of expeditions into space] . Dorling Kindersley, Munich 2007, ISBN 978-3-8310-1089-9 .
- ↑ Vanguard 1 in the NSSDCA Master Catalog , as of February 26, 2008.
- ↑ Vanguard 1 at space.skyrocket.de
- ^ Stöcker: Taschenbuch der Physik. 3rd edition 1998, p. 747.
- ↑ Live tracking from Vanguard 1 on n2yo.com.
- ↑ "Grapefruit satellite" has been orbiting the earth for 50 years. In: Image of Science. March 17, 2008, archived from the original on January 27, 2018 ; accessed in March 2008 .
- ↑ Vanguard on Gunter's Space Page , accessed March 17, 2018