Ranger 2

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Ranger 2
Ranger 2.jpg
Ranger 2
Mission type Technology
Operator NASA
Harvard designation 1961 Alpha Theta 1
SATCAT № 206
Mission duration 2 days
Spacecraft properties
Manufacturer Jet Propulsion Laboratory
Launch mass 304 kilograms (670 lb)
Start of mission
Launch date 18 November 1961, 08:09:00 (1961-11-18UTC08:09Z) UTC
Rocket Atlas LV-3 Agena-B
Launch site Cape Canaveral LC-12
End of mission
Decay date 20 November 1961 (1961-11-21)
Orbital parameters
Reference system Geocentric
Regime Low Earth
(High Earth planned)
Semi-major axis 6,574.2 kilometres (4,085.0 mi)
Perigee 150 kilometres (93 mi)
Apogee 242 kilometres (150 mi)
Inclination 33.3 degrees
Period ~89 minutes
Lyman-Alpha Telescope

Ranger 2 was a flight test of the Ranger spacecraft system of the NASA Ranger program designed for future lunar and interplanetary missions. Ranger 2 was designed 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.[1]

Spacecraft design[edit]

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-meter-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.[1]

The communications system included the high-gain antenna and an omnidirectional 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.[1]


The spacecraft was launched 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 orbit decayed, and the spacecraft reentered Earth's atmosphere on 20 November 1961.[1]

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