Vanguard 1

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Vanguard 1 was the fourth satellite in the orbit after Soviet Sputnik 1, Sputnik 2, and US Explorer 1. It was the first satellite using solar energy. The communication was lost 1964, but it remains in the orbit and thus it became the oldest man made object in Earth orbit.

The satellite has spherical shape (16.5 cm in diameter) made from aluminium and weight was 1.46 kg.  The 10mW 108 MHz telemetry transmitter was powered by a mercury batter and the 5mW 108.03 MHz Minitrack beacon transmitter was powered by 6 solar cells on the surface of the spherical body. It contained 6 sticking aluminium antennas, 30 cm long and of 0.8 cm diameter. They passed through the center of the sphere. Vanguard 1 carried two thermistors which measured the interior temperature over 16 days in order to follow the thermal protection.

Vanguard was name both for the satellite and launch vehicle. It had 3 stages. The first stage was powered by liquid rocket engine propelled by RP-1 and liquid oxygen. It didn't have fins, was about 13.4 high and diameter was 1.14 m. The second stage was 5.8 m tall and diameter was 0.8 m. This stage had guidance and control system. The third stage was a solid propellant rocket.  The total height of the rocket was 21.9 m.

The payload capacity was about 11 kg to 555 km Earth orbit.

Vanguard 1 composite.jpg
Graphic picture

There was 2 experiments which returned to the Earth:

  1. Radio Beacon for Ionospheric studies: transmitter which was powered by 10 mW mercury battery on 108 MHz and transmitter powered by 6 cells on 108.03 MHz to be used as angle tracking system.  
  2. Satellite Drag Atmospheric Density: experiment used to determine upper atmospheric densities as a function of altitude, latitude and season and solar activity. Time range: 1958 May 17 - 1961 October 10. The density values were computed for the height of 658 km. Values are mostly in tabular form.

Satellite drag


Drag also called air resistance, is a force acting on an object moving through the surrounding fluid. Drag acts opposite to the direction of the motion and so it tends to slow an object. 
























































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































Vanguard 1 rocket on the pad at Cape Canaveral awaiting for the launch 





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