Vanguard 3

Launch data Designation 00020 / 1959 Eta1 / 59007A Launch date 18 Sep 1959 - 5:20:07 UT Launch site CC, LC18A Launch vehicle Vanguard SLV-7 (#11) Satellite type 20in Magnetometer, X-Ray, Env. #1 Mission Scientific: Sun study Earth orbit on Sep 18, 1959 (.3): Perigee/Apogee 512 x 3744 km Eccentricity  0.190 Inclination 33.35° Period 130,00 min Earth orbit on May 24, 2000 (.49): Perigee / Apogee  511 x 3379 km Eccentricity  0.172 Inclination  33,34° Period  125.93 min

Spacecraft data: Prime contractor   Operator  NASA Mass at launch  23 kg (45 kg?) Payload  23 kg Basic shape  Rocket-sphere Dimension  2,5 long 0,51 dia Design lifetime  200 years

Mission details:

Vanguard 3 was launched by a Vanguard (mod) rocket from the Eastern Test Range into a geocentric orbit. The objectives of the flight were to measure the earth's magnetic field, the solar X-ray radiation and its effects on the earth's atmosphere, and the near-earth micrometeoroid environment. Instrumentation included a proton magnetometer, X-ray ionization chambers, and various micrometeoroid detectors. The spacecraft was a 50.8-cm-diameter magnesium sphere. The magnetometer was housed in a glass fiber phenolic resin conical tube attached to the sphere. Data transmission stopped on December 11, 1959, after 84 days of operation. The data obtained provided a comprehensive survey of the earth's magnetic field over the area covered, defined the lower edge of the Van Allen radiation belt, and provided a count of micrometeoroid impacts. Vanguard 3 has an expected orbital lifetime of 200 yr. 

Satellite tracking: