The Project Vanguard reference article from the English Wikipedia on 24-Jul-2004 (provided by Fixed Reference: snapshots of Wikipedia from wikipedia.org)

Project Vanguard

Project Vanguard was the name of the program that launched the first satellites from the United States.

Table of contents

1 The DOD Committee on Special Capabilities 2 The Navy's proposal 3 Sputnik II and Explorer I

The DOD Committee on Special Capabilities

In August 1955, the DOD Committee on Special Capabilities chose the NRL 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

Project Vanguard was chosen from three proposals 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 non-existent Atlas rocket.

The Navy's proposal

The Navy proposed designing a rocket system based on the Viking and Aerobee rocket systems, for the purposes of launching the first US satellite.

The Naval Research Laboratory was given overall responsibility for the project while funding came from the National Science Foundation. The 1.4kg spherical Vanguard satellites (designated "Test Vehicles" prior to launch) were built at the Naval Research Laboratory in Washington, 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.

Sputnik II and Explorer I

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 2466 miles and a perigee of 404 miles; it was estimated that it would remain in orbit for 240 years, and Vanguard 1 remains the oldest satellite still in orbit at this time. The radio continued to transmit until 1965, 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.

Vanguard met 100 percent of its scientific objectives, providing a wealth of information on the size and shape of Earth, air density, temperature ranges, and micrometeorite impact. It proved that solar cells could be used for several years to power radio transmitters, with its solar cells operating for about seven years. Ground-based tracking of the now-inert Vanguards continues to provide information about the effects of the Sun, Moon and atmosphere on satellite orbits.

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