Vanguard 1
Organization	United States Navy
Major contractors	United States Naval Research Laboratory (NRL)
Mission type	Earth science
Satellite of	Earth
Launch date	March 17, 1958 at 12:15:41 UTC
Launch vehicle	Vanguard rocket
Mission duration	May 1964; ~2,200 days
NSSDC ID	1958-002B
Webpage	NSSDC Master Catalog
Mass	1.47 kg (3.2 lb)
Semimajor axis	8,689.7 km (5,399.5 mi)
Eccentricity	0.1909
Inclination	34.25°
Orbital period	134.2 minutes
Apoapsis	3,969 km (2,466 mi)
Periapsis	654 km (406 mi)
Orbits	~196,000 as of March 16, 2008

Vanguard 1 was the fourth artificial satellite launched, and is the oldest still orbiting Earth, though there is no longer any communication with it. As of August 2007, it remains the oldest piece of space junk still in orbit.^[1] It was also the first satellite to be solar powered.^[2] It was designed to test the launch capabilities of a three-stage launch vehicle as a part of Project Vanguard, and the effects of the environment on a satellite and its systems in Earth orbit. It also was used to obtain geodetic measurements through orbit analysis. Vanguard 1 satellite (NASA) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... USN redirects here. ... Bust of Thomas Edison at the front gate of the Naval Research Laboratory. ... Earth science (also known as geoscience, the geosciences or the Earth Sciences), is an all-embracing term for the sciences related to the planet Earth. ... This article is about Earth as a planet. ... is the 76th day of the year (77th in leap years) in the Gregorian calendar. ... Jan. ... UTC redirects here. ... The Vanguard rocket is the first space launch vehicle of the United States. ... The National Space Science Data Center (NSSDC) is a department in NASAs Solar System Exploration Division. ... In astrodynamics, under standard assumptions any orbit must be of conic section shape. ... For the science fiction novella by William Shunn, see Inclination (novella). ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... is the 75th day of the year (76th in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... For other uses, see Satellite (disambiguation). ... Space Debris Space debris or orbital debris, also called space junk, are the objects in orbit around Earth created by man that no longer serve any useful purpose. ... A Saturn V launch vehicle sends Apollo 15 on its way to the moon. ... 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. ... This article or section should include material from Erdmessung. ...

Spacecraft design

The spacecraft is a 1.47 kg (3.2 lb) aluminum sphere 152 mm (6 inch) in diameter. It contains a 10 mW, 108 MHz transmitter powered by a mercury battery and a 5 mW, 108.03 MHz transmitter that was powered by six solar cells mounted on the body of the satellite. Six short antennas protrude from the sphere. The transmitters were used primarily for engineering and tracking data, but were also used to determine the total electron content between the satellite and ground stations. Vanguard also carries two thermistors which measured the interior temperature over sixteen days in order to track the effectiveness of the thermal protection. A backup version of Vanguard 1 is on display at the Kansas Cosmosphere and Space Center. Aluminum is a soft and lightweight metal with a dull silvery appearance, due to a thin layer of oxidation that forms quickly when it is exposed to air. ... For other uses, see Sphere (disambiguation). ... A mercury battery (also called mercuric oxide battery, or mercury cell) is a non-rechargeable electrochemical battery, a primary cell. ... A solar cell, made from a monocrystalline silicon wafer A solar cell or photovoltaic cell is a device that converts light energy into electrical energy. ... A Yagi-Uda beam antenna Short Wave Curtain Antenna (Moosbrunn, Austria) A building rooftop supporting numerous dish and sectored mobile telecommunications antennas (Doncaster, Victoria, Australia) An antenna is a transducer designed to transmit or receive radio waves which are a class of electromagnetic waves. ... TEC is an important descriptive quantity for the ionosphere of the Earth. ... NTC thermistor, bead type, insulated wires Thermistor symbol A thermistor is a type of resistor used to measure temperature changes, relying on the change in its resistance with changing temperature. ... The Kansas Cosmosphere and Space Center is a museum and educational facility in Hutchinson, Kansas that is best known for the display and restoration of space artifacts. ...

Mission

The three stage launch vehicle placed Vanguard into a 654×3969 km (406×2466 mi.), 134.2 minute elliptical orbit inclined at 34.25 degrees on March 17, 1958. Original estimates had the orbit lasting for 2000 years, but it was discovered that solar radiation pressure and atmospheric drag during high levels of solar activity produced significant perturbations in the perigee height of the satellite, which caused a significant decrease in its expected lifetime to only about 240 years. For the science fiction novella by William Shunn, see Inclination (novella). ... is the 76th day of the year (77th in leap years) in the Gregorian calendar. ... Jan. ... Radiation pressure is the pressure exerted upon any surface exposed to electromagnetic radiation. ... Atmospheric drag is a form of drag, which is the force that opposes an object moving through a liquid or gas. ...

Mission results

Radio beacon

A 10 mW mercury battery powered transmitter on the 108 MHz band used for International Geophysical Year (IGY) scientific satellites, and a 5 mW, 108.03 MHz^[3] transmitter powered by six solar cells were used as part of a radio phase-comparison angle-tracking system. The tracking data was used to show that the shape of the Earth has a north-south asymmetry, occasionally described as pear-shaped with the stem at the North Pole. These radio signals were also used to determine the total electron content between the satellite and selected ground-receiving stations. The battery-powered transmitter provided internal package temperature for about sixteen days and sent tracking signals for twenty days. The solar cell powered transmitter operated for more than six years. Signals gradually weakened and were last received at Quito, Ecuador in May 1964 after which the spacecraft was optically tracked from Earth. The International Geophysical Year or IGY was an international scientific effort that lasted from July 1, 1957, to December 31, 1958. ... The expression figure of the Earth has various meanings in geodesy according to the way it is used and the precision with which the Earths size and shape is to be defined. ...

Satellite drag atmospheric density

Because of its symmetrical shape, Vanguard 1 was selected by the experimenters for use in determining upper atmospheric densities as a function of altitude, latitude, season, and solar activity. This experiment was not planned prior to launch. Density values near perigee were deduced from sequential observations of the spacecraft position, using optical (Baker-Nunn camera network) and radio and/or radar tracking techniques. This experiment obtained reasonable density values. 2m Schmidt Camera (Alfred-Jensch-Telescope Tautenburg, Thuringia, Germany A Schmidt camera is an astronomical camera designed to provide wide fields of view with limited aberrations. ...

Fiftieth anniversary

On March 17, 2008 the Vanguard 1 satellite, the oldest man-made object in space from Planet Earth, logged its 50th year in Earth orbit. is the 76th day of the year (77th in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ...

A small group of former U.S. Naval Research Laboratory and NASA workers has been in communication, and a number of government agencies have been asked to commemorate the event. The Naval Research Laboratory will commemorate the event with a day-long meeting at NRL on March 17, 2008.^[4] The National Academy of Sciences has scheduled some seminars to mark the 50th anniversary of the International Geophysical Year, but at this time, these are the only official observances known.^[5] The US Naval Research Laboratory (NRL) is the corporate research laboratory for the United States Navy and the United States Marine Corps and conducts a broad program of scientific research and advanced development. ... For other uses, see NASA (disambiguation). ... is the 76th day of the year (77th in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Anno Domini (or common era), in accordance to the Gregorian calendar. ... President Harding and the National Academy of Sciences at the White House, Washington, DC, April 1921 The National Academy of Sciences (NAS) is a corporation in the United States whose members serve pro bono as advisers to the nation on science, engineering, and medicine. ...

References