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ANNA 1A (Army, Navy, NASA, Air Force 1A, also known as the Flashing Light Geodetic Satellite) failed to reach orbit due to a failure in the 2nd stage ignition. It was launched on 10 May 1962 on a Thor Able-Star from Cape Canaveral with the objectives of obtaining precise geocentric positional data for observational ground stations, and to provide data on the geogravitational potential. It was identical to the ANNA 1B spacecraft launched on 31 October 1962 except for the exterior paint pattern. It was a joint U.S. Army, Navy, NASA, and Air Force satellite.

The program objectives were: 1) evaluation of orbital techniques for geodesy; 2) establish geocentric positions and general shape of the Earth; 3) study the geogravitational potential; 4) study air density by analysis of effects of air drag on the satellite; 5) calibration and evaluation of electronic ranging equipment; and 6) measurement of atmospheric attenuation of light.

Spacecraft and Subsystems

The spacecraft body was a 107 cm (42 in) diameter aluminum and fiberglass spheroid with a 35.5 cm (14 in.) wide, 12-sided polygonal band of solar cells encircling its equator. The band was 117 cm (46 in.) in diameter. Total mass of the satellite was 161 kg. A pair of xenon flashlamp stroboscopic beacons were mounted on opposite sides of the solar cell band, designed to emit a sequence of five 1.2 millisecond flashes (1100 Joules per flash) at 5.6 second intervals, controlled by a clock timer mounted inside the spacecraft and tracked on the ground by the Smithsonian optical net. The GaAs solar cells provided an average of 22 W to rechargeable NiCd batteries.

The spacecraft held eight transmitters, one at 136 MHz and 400 mW; two for geodetic measurements at 162 MHz (225 mW) and 324 MHz (400 mW); two for refraction studies and as spares for the geodetic measurements (54 MHz, 450 mW and 216 MHz, 225 mW), and two for the SECOR instrument (224.5 MHz, 100 mW and 449.0 MHz, 1 W). Passive thermal control was achieved via Kropschott insulation and a diffusively reflecting construction and paint pattern. A permanent magnet was mounted in the spacecraft to maintain the stable attitude of the spacecraft within 3 degrees with respect to the Earth's magnetic field, giving the spacecraft a "north" face and a "south" face.

The spacecraft carried two instruments in addition to the optical beacons. The SEquential COllation of Range (SECOR) instrument consisted of a transponder tracking system designed to allow ground tracking systems to make a phase comparison between a modulating frequency transmitted to and returned from the spacecraft. The instrument had a receiver and two transmitters using three frequencies in the VHF-UHF bands, one for transmission to the spacecraft and two coherent frequencies for transmission from the spacecraft to the ground. The TRANSIT range rate transmitters used four ultra-stable frequency transmissions broadcast continuously to observe Doppler shift. The transmitters comprise two stable oscillators, two frequency multipliers, and four power-amplifiers. All four transmissions are coherent.

Alternate Names

  • Anna1A
  • Flashing Light Geodetic Satellite

Facts in Brief

Launch Date: 1962-05-10
Launch Vehicle: Thor-Able-Star
Launch Site: Cape Canaveral, United States
Mass: 160 kg

Funding Agency

  • Department of Defense-Department of the Air Force (United States)


  • Navigation/Global Positioning

Additional Information

Questions and comments about this spacecraft can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail

Anna 1B diagram

Anna spacecraft diagram.

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