Andrew Yee[_1_]
March 20th 08, 01:23 AM
Public Affairs Office
Naval Research Laboratory
Washington, D.C.
3/17/2008
NRL Press Release: 6-08r
Vanguard I Celebrates 50 Years in Space
The Vanguard I satellite celebrates its 50th birthday this year. Its launch
on March 17, 1958 from Cape Canaveral, Florida, culminated the efforts of
America's first official space satellite program begun in September 1955.
The first solar-powered satellite, Vanguard I has the distinction of being
the oldest artificial satellite orbiting the Earth. Its predecessors,
Sputniks I and II and Explorer I, have since fallen out of orbit.
The Vanguard I was launched as part of the United States' participation in
the International Geophysical Year (July 1957 to December 1958) in a
tri-service project with the U.S. Army operating the tracking stations and
the U.S. Air Force providing the launching site. As part of the scientific
program for the International Geophysical Year, the Naval Research
Laboratory was officially delegated the responsibility of placing an
artificial satellite with a scientific experiment into orbit around the
Earth. NRL developed the launch vehicles; developed and installed the
satellite tracking system; and designed, constructed and tested the
satellites in a program headed by Dr. John Hagen. NRL's proposal to conduct
Project Vanguard was based on experience gained from extensive use of German
V-2 and Viking rockets to probe the Earth's upper atmosphere.
Vanguard I is 6 inches in diameter and weighs about 3 pounds. Its small
size, compared to the Soviet's 200-pound Sputnik I, caused then-Soviet
Premier Nikita Khrushchev to dub it "the grapefruit satellite."
In the 50 years following Vanguard's launch the 3-pound satellite made more
than 196,990 revolutions of the Earth and travelled 5.7 billion nautical
miles, the distance from Earth to beyond the planet Pluto and halfway back.
In that time it has provided a wealth of information on the size and shape
of the Earth, and set a number of space records as well.
The successes of Vanguard I set the pattern for a multitude of other space
ventures in this country and abroad. Vanguard also served as a springboard
for NRL scientists to launch several series of space probes to study various
aspects of radiation phenomena.
Vanguard I introduced much of the technology that has been applied in other
U.S. satellite programs. 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. Now the oldest man-made
satellite in orbit, Vanguard I has been 100 percent successful in meeting
its scientific objectives. It accomplished the following:
* First orbiting package to be powered by solar energy.
* Returned a wealth of information on air density, temperature ranges and
micrometeorite impact.
* Maintained an orbit so stable that cartographers were able to more
accurately redrawn maps of islands in the Pacific Ocean.
* Revealed that the Earth is slightly pear-shaped rather than round.
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. For example:
* Fifteen years after its launch, Vanguard was in an orbit with an apogee
height of 2,121 nautical miles above the Earth's surface, and a perigee of
about 353.6 nautical miles. The orbit period was approximately 133.8
minutes.
* By 2000 Vanguard was in an orbit with an apogee height of 2,073 nautical
miles above the Earth's surface, a perigee of 352 nautical miles, and an
orbit period of 132.8 minutes.
In conjunction with the Vanguard launch, NRL scientists laid out a worldwide
tracking system called Minitrack. Laboratory scientists later used many of
the principles embodied in this system to develop a Space Surveillance
System that can detect unannounced, radio-silent satellites passing over the
U.S.
Although Vanguard I's solar-powered radio transmitter stopped transmitting
in 1964, U.S. space surveillance systems still track the spacecraft.
When it was launched 50 years ago, it was estimated that the satellite's
life expectancy would be about 200 years. Since then, scientists have
extended this estimate to 2000 years. Accordingly, Vanguard I should be
celebrating many more birthdays in space.
For more information about the 50th anniversary of Vanguard I, see the
website
http://www.nrl.navy.mil/vanguard50
Naval Research Laboratory
Washington, D.C.
3/17/2008
NRL Press Release: 6-08r
Vanguard I Celebrates 50 Years in Space
The Vanguard I satellite celebrates its 50th birthday this year. Its launch
on March 17, 1958 from Cape Canaveral, Florida, culminated the efforts of
America's first official space satellite program begun in September 1955.
The first solar-powered satellite, Vanguard I has the distinction of being
the oldest artificial satellite orbiting the Earth. Its predecessors,
Sputniks I and II and Explorer I, have since fallen out of orbit.
The Vanguard I was launched as part of the United States' participation in
the International Geophysical Year (July 1957 to December 1958) in a
tri-service project with the U.S. Army operating the tracking stations and
the U.S. Air Force providing the launching site. As part of the scientific
program for the International Geophysical Year, the Naval Research
Laboratory was officially delegated the responsibility of placing an
artificial satellite with a scientific experiment into orbit around the
Earth. NRL developed the launch vehicles; developed and installed the
satellite tracking system; and designed, constructed and tested the
satellites in a program headed by Dr. John Hagen. NRL's proposal to conduct
Project Vanguard was based on experience gained from extensive use of German
V-2 and Viking rockets to probe the Earth's upper atmosphere.
Vanguard I is 6 inches in diameter and weighs about 3 pounds. Its small
size, compared to the Soviet's 200-pound Sputnik I, caused then-Soviet
Premier Nikita Khrushchev to dub it "the grapefruit satellite."
In the 50 years following Vanguard's launch the 3-pound satellite made more
than 196,990 revolutions of the Earth and travelled 5.7 billion nautical
miles, the distance from Earth to beyond the planet Pluto and halfway back.
In that time it has provided a wealth of information on the size and shape
of the Earth, and set a number of space records as well.
The successes of Vanguard I set the pattern for a multitude of other space
ventures in this country and abroad. Vanguard also served as a springboard
for NRL scientists to launch several series of space probes to study various
aspects of radiation phenomena.
Vanguard I introduced much of the technology that has been applied in other
U.S. satellite programs. 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. Now the oldest man-made
satellite in orbit, Vanguard I has been 100 percent successful in meeting
its scientific objectives. It accomplished the following:
* First orbiting package to be powered by solar energy.
* Returned a wealth of information on air density, temperature ranges and
micrometeorite impact.
* Maintained an orbit so stable that cartographers were able to more
accurately redrawn maps of islands in the Pacific Ocean.
* Revealed that the Earth is slightly pear-shaped rather than round.
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. For example:
* Fifteen years after its launch, Vanguard was in an orbit with an apogee
height of 2,121 nautical miles above the Earth's surface, and a perigee of
about 353.6 nautical miles. The orbit period was approximately 133.8
minutes.
* By 2000 Vanguard was in an orbit with an apogee height of 2,073 nautical
miles above the Earth's surface, a perigee of 352 nautical miles, and an
orbit period of 132.8 minutes.
In conjunction with the Vanguard launch, NRL scientists laid out a worldwide
tracking system called Minitrack. Laboratory scientists later used many of
the principles embodied in this system to develop a Space Surveillance
System that can detect unannounced, radio-silent satellites passing over the
U.S.
Although Vanguard I's solar-powered radio transmitter stopped transmitting
in 1964, U.S. space surveillance systems still track the spacecraft.
When it was launched 50 years ago, it was estimated that the satellite's
life expectancy would be about 200 years. Since then, scientists have
extended this estimate to 2000 years. Accordingly, Vanguard I should be
celebrating many more birthdays in space.
For more information about the 50th anniversary of Vanguard I, see the
website
http://www.nrl.navy.mil/vanguard50