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The Radio Astronomy Explorer A (RAE-A, or RAE-1, also designated Explorer 38) spacecraft measured the intensity of celestial radio sources, particularly the Sun, as a function of time, direction, and frequency (0.2 to 20 MHz). The spacecraft was gravity gradient oriented. The spacecraft weight was 193 kg, and average power consumption was 25 W.

The experiment antenna package, made of BeCu, consisted of very long traveling wave antennas forming an X configuration: a 229-m upper V-antenna pointed away from the Earth; a 229-m lower V-antenna pointed toward the Earth, with a 60 degree angle between the two legs of the "V". Each of the four legs of the two V-antennas was cut one-quarter of the way from its tip and a 600-ohm resistor was inserted. A 37-m dipole antenna ran through the spacecraft parallel to the lunar surface in the same plane as the two V-antennas. There was also a 192-m boron libration damper boom system used to damp out any spacecraft oscillations about the equilibrium position.

The spacecraft was also equipped with one 136-MHz telemetry turnstile. The onboard experiments consisted of four step-frequency Ryle-Vonberg radiometers operating from 0.45 to 9.18 MHz, two multichannel total power radiometers operating from 0.2 to 5.4 MHz, one step frequency V-antenna impedance probe operating from 0.24 to 7.86 MHz, and one dipole antenna capacitance probe operating from 0.25 to 2.2 MHz. RAE-1 was designed for a 1-year minimum operating lifetime. The spacecraft tape recorder performance began to deteriorate after 2 months in orbit. In spite of several cases of instrument malfunction, good data were obtained on all three antenna systems. For more details, see R. R. Weber, J. K. Alexander, and R. G. Stone, Radio Sci., v. 6, p. 1085, 1971.

Alternate Names

  • 03307
  • Explorer 38
  • RAE 1
  • Radio Astronomy Explorer

Facts in Brief

Launch Date: 1968-07-04
Launch Vehicle: Delta
Launch Site: Vandenberg AFB, United States
Mass: 602 kg

Funding Agency

  • NASA-Office of Space Science Applications (United States)


  • Space Physics
  • Solar Physics
  • Astronomy

Additional Information

Questions and comments about this spacecraft can be directed to: Coordinated Request and User Support Office



NameRoleOriginal AffiliationE-mail
Dr. Robert G. StoneProject ScientistNASA Goddard Space Flight
Dr. Nancy G. RomanProgram ScientistNASA Headquarters
Mr. John T. SheaProject ManagerNASA Goddard Space Flight Center

Selected References

  • Mechanical design of Radio Astronomy Explorer (A), NASA-GSFC, X-723-70-255, Greenbelt, MD, June 1970.
  • Weber, R. R., et al., The Radio Astronomy Explorer satellite, a low frequency observatory, NASA-GSFC, TMX-65616, X-693-71-64, Greenbelt, MD, June 1971.

[RAE-A Diagram]

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