Naval Research Laboratory
Wednesday, March 12, 2003
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
