Vanguard
I - the World's Oldest Satellite Still in Orbit
Vanguard I,
the world's longest orbiting man-made satellite, built by the Naval
Research Laboratory (NRL) and launched at Cape
Canaveral,
Florida, in 1958, marked its 40th year in space on March 17, 1998.
In the years following Vanguard's launch, the small satellite has
made more than 158,061 revolutions of the earth and traveled over
4.59 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.) Fifteen cm in diameter and weighing just 1.4 kg,
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 given 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's Space Technology Center
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. Some of NRL's Project Vanguard members
joined NASA, forming the nucleus of the Goddard Space
Flight Center. The
Space Technology Center at NRL was redesignated the Naval Center for
Space Technology and
given overall responsibility to conceive, develop, and demonstrate space and aerospace
systems and technology to meet Navy, Department of Defense, and National needs.
In the years following Project
Vanguard's transfer to NASA, 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
developing the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) and the Extreme-ultraviolet Imaging Spectrometer (EIS) instruments for
NASA.
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 transmitter on board Vanguard 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.
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Vanguard
I Launch, March 1958
Engineering
Model of
Vanguard I Satellite
Vanguard
I Satellite on Display at the
Smithsonian Institution's National Air
and Space Museum
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