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Public Affairs Office
Naval Research Laboratory
Washington, D.C.

3/10/2003

NRL Press Release 21-03r

Vanguard Satellite Marks 45 Years in Space
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Vanguard I, the world's longest orbiting man-made satellite, built by 
the Naval Research Laboratory and launched at Cape Canaveral, Florida, 
in 1958, will mark its 45th year in space on March 17. In the years 
following Vanguard's launch, the small satellite has made more than 
178,061 revolutions of the earth and traveled over 5.1 billion 
nautical miles. 

The first solar-powered satellite, Vanguard I was the second 
artificial satellite successfully placed in earth orbit by the United 
States. (Vanguard predecessors, Sputniks I and II and Explorer I have 
long since fallen out of orbit.) Just six inches in diameter and 
weighing just 3 pounds, Vanguard was described by then-Soviet Premier 
Nikita Khrushchev as "the grapefruit satellite." 

As part of the scientific program for the International Geophysical 
Year (1957-58), NRL was officially delegated the responsibility of 
placing an artificial satellite with a scientific experiment into 
orbit around the earth. Designated Project Vanguard, the program was
placed under Navy management and DoD monitorship. 

NRL was responsible for developing the launch vehicles; developing and 
installing the satellite tracking system; and designing, constructing 
and testing the satellites.  The tracking system was called Minitrack. 
The Minitrack stations, designed, built and initially operated by NRL,
were along a North-South line running along the east coast of North 
America and the west coast of South America. Minitrack was the 
forerunner of another NRL-developed system called NAVSPASUR, which is
operational today and a major producer of spacecraft tracking data.

In late 1958, responsibility for Project Vanguard was transferred to 
NASA, forming the nucleus of the Goddard Space Flight Center. After 
the transfer, NRL rebuilt their spacecraft technology capability and 
have developed some 87 satellites over the past 40 years for the Navy,
DoD and NASA. NRL's relationship with NASA is still very active; for 
example, NRL is currently developing the Interim Control Module for 
NASA's International Space Station.

Vanguard met 100 percent of its scientific objectives, providing a 
wealth of information on the size and shape of the earth, air density, 
temperature ranges and micrometeorite impact. It proved that the earth 
is pear-shaped, not round; corrected ideas about the atmosphere's 
density at high altitudes and improved the accuracy of world maps.

NRL space scientists say that the Vanguard I program introduced much 
of the technology that has since been applied in later U.S. satellite 
programs, from rocket launching to satellite tracking. For example, it 
proved that solar cells could be used for several years to power radio 
transmitters. Vanguard's solar cells operated for about seven years, 
while conventional batteries used to power another onboard transmitter 
lasted only 20 days.

Although Vanguard's solar-powered "voice" became silent in 1964, it 
continues to serve the scientific community.  Ground-based tracking of 
the satellite provides data concerning the effects of the sun, moon 
and atmosphere on satellite orbits.

More information about the Vanguard Project:
     http://www.nrl.navy.mil/content.php?P=VANGUARD

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