Vanguard SLV-6, also called Vanguard Satellite Launch Vehicle-Six, hoped to be the third successful flight of the American

Vanguard The vanguard (also called the advance guard) is the leading part of an advancing military formation. It has a number of functions, including seeking out the enemy and securing ground in advance of the main force. History The vanguard derives f ...

rocket following the successful

Vanguard 2 Vanguard 2 (or Vanguard 2E before launch) is an Earth-orbiting satellite launched 17 February 1959 at 15:55:02 GMT, aboard a Vanguard SLV-4 rocket as part of the United States Navy's Project Vanguard. The satellite was designed to measure clo ...

satellite on rocket Vanguard SLV-4. Vanguard Satellite Launch Vehicle-6 (SLV-6) was designed to carry a small spherical satellite into Earth orbit to study solar heating of Earth and the heat balance. A faulty second stage pressure valve caused a mission failure.

Launch vehicle

Vanguard was the designation used for both the launch vehicle and the satellite. The first stage of the three-stage Vanguard Test Vehicle was powered by a General Electric X-405 thrust liquid rocket engine, propelled by

kerosene Kerosene, paraffin, or lamp oil is a combustible hydrocarbon liquid which is derived from petroleum. It is widely used as a fuel in aviation as well as households. Its name derives from el, κηρός (''keros'') meaning " wax", and was re ...

(

RP-1 RP-1 (alternatively, Rocket Propellant-1 or Refined Petroleum-1) is a highly refined form of kerosene outwardly similar to jet fuel, used as rocket fuel. RP-1 provides a lower specific impulse than liquid hydrogen (LH2), but is cheaper, is s ...

) and

liquid oxygen Liquid oxygen—abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries—is the liquid form of molecular oxygen. It was used as the oxidizer in the first liquid-fueled rocket invented in 1926 by Robert H. Goddard, an app ...

, with

helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic ta ...

pressurant. It was finless, tall, in diameter, and had a launch mass of approximately . The second stage was a high, of diameter Aerojet General AJ-10 liquid engine burning

Unsymmetrical dimethylhydrazine Unsymmetrical dimethylhydrazine (UDMH; 1,1-dimethylhydrazine, НДМГ or codenamed Geptil) is a chemical compound with the formula H2NN(CH3)2 that is used as a rocket propellant. It is a colorless liquid, with a sharp, fishy, ammonia-like smell ...

(UDMH) and White Inhibited Fuming Nitric Acid (WIFNA) with a helium pressurant tank. It produced a thrust of and had a launch mass of approximately . This stage contained the complete guidance and control system. A solid-propellant rocket with of thrust (for 30 seconds burn time) was developed by the

Grand Central Rocket Company The Lockheed Propulsion Company was a division of the Lockheed Aircraft Corporation located at 1500 Crafton Avenue in the Mentone, California area northeast of Redlands, California, adjacent to the Santa Ana River, from 1961 to 1975. It developed, ...

to satisfy third-stage requirements. The stage was high, in diameter, and had a launch mass of . The thin

steel Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistan ...

casing for the third stage had a hemispherical forward dome with a shaft at the center to support the satellite and an aft dome fairing into a

exit nozzle. The total height of the vehicle with the satellite fairing was about . The payload capacity was to a Earth orbit. A nominal launch would have the first stage bringing the rocket to an altitude of , followed by the second stage to , whereupon the third stage would bring the satellite to orbit. This was the same launch vehicle configuration, with minor modifications, as used for

Vanguard TV-3 Vanguard TV-3 (also called Vanguard Test Vehicle-Three), was the first attempt of the United States to launch a satellite into orbit around the Earth, after the successful Soviet launches of Sputnik 1 and Sputnik 2. Vanguard TV-3 was a small s ...

and all succeeding Vanguard flights up to this one.

Spacecraft

The SLV-6 satellite was a , of diameter sphere. The shell was composed of

magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ...

alloy and the interior was pressurized. The payload instrumentation package was mounted in the center of the sphere. The package was arranged in a cylindrical stack with mercury batteries at the bottom, followed by the

Minitrack The Minitrack Network was the first U.S. satellite tracking network to become operational, in 1957. It was used to track the flights of Sputnik, Vanguard, Explorer, and other early space efforts. Minitrack was the progenitor of Spacecraft Trackin ...

tracking system electronics, the environment electronics, the telemetering instrumentation, and the experiment electronics. Below the package at the bottom of the sphere was the separation device, a spring loaded tube with a timer designed to push the satellite away from the third stage after orbit was reached. At the top of the interior of the sphere was a pressure gauge. Four spring-loaded metal rods were folded along the equator of the sphere and would protrude radially outward when deployed, acting as a turnstile antenna. Mounted at the end of each antenna rod was a thermistor to measure solar heating processes. Two transmitters were used, one of 10 mW broadcasting at 108.00 MHz and one of 100 mW at 108.03 MHz.

Launch

Vanguard SLV-6 launched on 22 June 1959 at 20:16:09

GMT Greenwich Mean Time (GMT) is the mean solar time at the Royal Observatory in Greenwich, London, counted from midnight. At different times in the past, it has been calculated in different ways, including being calculated from noon; as a cons ...

. It was launched from Launch Complex 18A (LC-18A) at the

Cape Canaveral Air Force Station Cape Canaveral Space Force Station (CCSFS) is an installation of the United States Space Force's Space Launch Delta 45, located on Cape Canaveral in Brevard County, Florida. Headquartered at the nearby Patrick Space Force Base, the statio ...

(CCAFS). The second stage helium control bottle valve failed to open properly at engine start. Tank and chamber pressures rapidly decayed during second stage burn, and 40 seconds after engine start, the helium bottle ruptured due to pressure buildup. The third stage then separated and ignited, driving itself and the satellite into the

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

downrange. astronautix.com, Vanguard
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Launch vehicle

Spacecraft

Launch

See also

References

Further reading