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Echo 2



The Echo 2 spacecraft was a 41-m balloon of aluminum foil-mylar laminate. Echo 2 was designed as a rigidized passive communications spacecraft for testing propagation, tracking, and communication techniques. Instrumentation included a beacon telemetry system that provided a tracking signal, monitored spacecraft skin temperature between -120 deg C and +16 deg C, and measured the internal pressure of the spacecraft between 5E-5 mm of mercury and 0.5 mm of mercury, especially during the initial inflation stages. This system, which consisted of two beacon assemblies, used solar cell panels for power and had a minimum power output of 45 mW at 136.17 MHz and 136.02 MHz. In addition to fulfilling its communications mission, the spacecraft was used for global geometric geodesy. The spacecraft re-entered the atmosphere on 07 June 1969.

Alternate Names

  • 00740
  • A 12
  • Echo-C
  • Echo2

Facts in Brief

Launch Date: 1964-01-25
Launch Vehicle: Thrust Augmented Thor-Agena B
Launch Site: Vandenberg AFB, United States
Mass: 256 kg

Funding Agency

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


  • Communications
  • Engineering
  • Earth Science

Additional Information

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



NameRoleOriginal AffiliationE-mail
Mr. Herbert L. EakerProject ManagerNASA Goddard Space Flight Center
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