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Ranger 2



This was a flight test of the Ranger spacecraft system designed for future lunar and interplanetary missions. Ranger 2 was designed to go into a deep space trajectory to test various systems for future exploration and to conduct scientific observations of cosmic rays, magnetic fields, radiation, dust particles, and a possible hydrogen gas "tail" trailing the Earth. A gyro failure resulted in the spacecraft being stranded in a low Earth orbit with a lifetime of less than a day.

Spacecraft and Subsystems

Ranger 2 was of the Ranger Block 1 design and was almost identical to Ranger 1. The spacecraft consisted of a hexagonal base 1.5 m across upon which was mounted a cone-shaped 4 m high tower of aluminum struts and braces. Two solar panel wings measuring 5.2 m from tip to tip extended from the base. A high-gain directional dish antenna was attached to the bottom of the base. Spacecraft experiments and other equipment were mounted on the base and tower. Instruments aboard the spacecraft included a Lyman-alpha telescope, a rubidium-vapor magnetometer, electrostatic analyzers, medium-energy-range particle detectors, two triple coincidence telescopes, a cosmic-ray integrating ionization chamber, cosmic dust detectors, and scintillation counters.

The communications system included the high gain antenna and an omni-directional medium gain antenna and two transmitters at approximately 960-mhz, one with 0.25 W power output and the other with 3 W power output. Power was to be furnished by 8680 solar cells on the two panels, a 53.5 kg silver-zinc battery, and smaller batteries on some of the experiments. Attitude control was provided by a solid-state timing controller, Sun and Earth sensors, gyroscopes, and pitch and roll jets. The temperature was controlled passively by gold plating, white paint, and polished aluminum surfaces.

Mission Profile

The spacecraft was launched on 18 November 1961 at 08:12:21.5 UT into a low Earth parking orbit, but an inoperative roll gyro prevented Agena restart. The spacecraft could not be put into its planned deep-space trajectory, resulting in Ranger 2 being stranded in low Earth orbit upon separation from the Agena stage. The last data were received by a small mobile tracking antenna in Johannesburg, South Africa on 18 November at 14:56 UT. The orbit decayed and the spacecraft reentered Earth's atmosphere on at about 04:00 UT on 19 November 1961.

Total research, development, launch, and support costs for the Ranger series of spacecraft (Rangers 1 through 9) was approximately $170 million.

Upper spacecraft rendered image credit NASA/NSSDCA (public domain)

Alternate Names

  • 00206
  • 1961 Alpha Theta 1
  • Ranger2

Facts in Brief

Launch Date: 1961-11-18
Launch Vehicle: Atlas-Agena B
Launch Site: Cape Canaveral, United States
Mass: 304 kg

Funding Agency

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


  • Planetary Science
  • Space Physics
  • Solar Physics

Additional Information

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



NameRoleOriginal AffiliationE-mail

Selected References

  • Scientific experiments for Ranger 1 and 2, JPL, Calif. Inst. Technol., TR 32-55, Pasadena, CA, Jan. 1961.
  • Ranger probe fails: Lunar shot still set, Space Technol. International, 5, No. 1, 23, Jan. 1962.
Image of Ranger block 1

Other Ranger Information/Data at NSSDCA

Ranger 1
Ranger 2
Ranger 3
Ranger 4
Ranger 5
Ranger 6
Ranger 7
Ranger 8
Ranger 9
Ranger Home Page

Rendering of Ranger block 1 Rendered Ranger block 1 spacecraft image credit NASA/NSSDCA (public domain)

Related Information/Data at NSSDCA

Moon Home Page
Moon Fact Sheet

Other Sources of Ranger Information/Data

Lunar Impact: A History of Project Ranger

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