Jump to content

Project Vanguard

From Wikipedia, the free encyclopedia

This is an old revision of this page, as edited by Yakobbokay (talk | contribs) at 02:11, 6 December 2006 (switched lb and kg order to match other entries). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Vanguard Rocket

Project Vanguard was the name given to the first United States program that was commissioned to design and launch the first artificial satellite into Earth orbit. The surprise launch of Sputnik I on October 4, 1957 shocked the U.S. and led to the start of a parallel crash program by the U.S. Army, that eventually launched the first U.S. satellite, Explorer I. The spectacular televised failure of Vanguard TV3 on December 6, 1957 deepened American dismay near the height of the Cold War.

On March 17, 1958 Vanguard I became the second artificial satellite successfully placed in Earth orbit by the United States. It was the first solar-powered satellite. Just 152 mm (six inches) in diameter and weighing just 1.4 kg (3 pounds), Vanguard I was described by then-Soviet Premier Nikita Khrushchev as "the grapefruit satellite."

Vanguard I is the oldest human-launched object still in space. Vanguard's predecessors, Sputniks 1 and 2 and Explorer I have long since fallen out of orbit.

Project history

As part of planning for the International Geophysical Year (1957 - 1958), the U.S. publicly undertook to place an artificial satellite with a scientific experiment into orbit around the Earth.

The three services' proposals

Proposals to do this were presented by the United States Air Force, the United States Army, and the United States Navy. The Army's ABMA under Dr. Wernher von Braun had suggested using a modified Redstone rocket (see: Juno I) while the Air Force had proposed using the Atlas rocket, which did not yet exist. The Navy proposed designing a rocket system based on the Viking and Aerobee rocket systems, for the purposes of launching the first US satellite.

In August 1955, The DOD Committee on Special Capabilities chose the Navy's proposal as it appeared most likely to, by spring 1958, fulfill the following:

  • 1) place a satellite in orbit during the IGY
  • 2) accomplish a scientific experiment in orbit
  • 3) track the satellite and ensure its attainment of orbit

Another consideration was that the Navy proposal used civilian rockets rather than military missiles, which were considered inappropriate for peaceful scientific exploration. Designated Project Vanguard, the program was placed under Navy management and DoD monitorship. The Naval Research Laboratory (NRL) in Washington was given overall responsibility, while funding came from the National Science Foundation. The director was John P. Hagen (1908-1990), an astronomer who in 1958 would become the assistant director of space flight development with the formation of NASA[1]. The 1.4 kg spherical Vanguard satellites (designated "Test Vehicles" prior to launch) were built at the NRL, and contained as their payload seven mercury cell batteries in a hermetically sealed container, two tracking radio transmitters, a temperature sensitive crystal, and six clusters of solar cells on the surface of the sphere.

NRL was also 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 remains operational today under the control of the Air Force and is a major producer of spacecraft tracking data.

Sputnik and Explorer I

TV-3 on display at NASM

On October 4, 1957, the Vanguard team learned of the launch of Sputnik I by the USSR while still working on a test vehicle (TV-2) designed to test the first stage of their launcher rocket. After the Soviet Union launched Sputnik II, on November 3, 1957, the Secretary of Defense directed the Army to use the Juno I and launch a satellite. At 11:45 AM on December 6 an attempt was made to launch TV-3; the rocket rose about four feet into the air, then immediately sank back down to the launch pad and exploded. The payload nosecone detached in the process and landed free of the exploding rocket. The satellite was too damaged for further use; it now resides in the National Air and Space Museum. On February 1, the ABMA managed to launch the Explorer I satellite.

On March 17, 1958, the program successfully launched the Vanguard satellite TV-4. TV-4 achieved a stable orbit with an apogee of 3,969 km (2466 miles) and a perigee of 650 km (404 miles) ; it was estimated that it would remain in orbit for 240 years, and Vanguard 1 remains the oldest human-made satellite still in orbit at this time. The radio continued to transmit until 1964, and tracking data obtained with this satellite revealed that Earth is not quite round - it is elevated at the North Pole and flattened at the South Pole. The Vanguard program was transferred to NASA when that agency was created in mid-1958. The program ended with the launch of Vanguard 3 in 1959.

In late 1958, with responsibility for Project Vanguard having been transferred to NASA, the nucleus of the Goddard Space Flight Center was formed. 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.

Accomplishments

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 slightly pear-shaped, not perfectly 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 on-board 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 now-inert Vanguards continues to provide information about the effects of the Sun, Moon and atmosphere on satellite orbits. Vanguard I marked its 48th year in space on March 17, 2006. In the years following its launch, the small satellite has made more than 178,061 revolutions of the Earth and traveled over 9.4 billion km (5.1 billion nautical miles).

Launch history

Vanguard rocket explodes shortly after launch at Cape Canaveral (December 6, 1957).

The Vanguard rocket launched 3 satellites out of 11 launch attempts:

See also

Retrieved from "https://en.wikipedia.org/enwiki/w/index.php?title=Project_Vanguard&oldid=92367743"