Ranger 2

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<tr><th bgcolor="#CCCCCC">Satellite of:</th><th>Earth</th></tr><tr><th bgcolor="#CCCCCC">Launch Date:</th><th>November 18, 1961 at 08:09:00 UTC</th></tr><tr><th bgcolor="#CCCCCC">Launch Vehicle:</th><th>Atlas-Agena B</th></tr><tr><th bgcolor="#CCCCCC">Decay:</th><th>November 20, 1961</th></tr><tr><th bgcolor="#CCCCCC">Mission Duration:</th><th>2 days</th></tr><tr><th bgcolor="#CCCCCC">NSSDC ID:</th><th>1961-032A</th></tr><tr><th bgcolor="#CCCCCC">Webpage:</th><th>NASA NSSDC Master Catalog</th></tr><tr><th bgcolor="#CCCCCC">Mass:</th><th>304 kg</th></tr><tr><th bgcolor="#CCCCCC">Semimajor Axis:</th><th>6,574.2 km</th></tr><tr><th bgcolor="#CCCCCC">Eccentricity:</th><th>.?</th></tr><tr><th bgcolor="#CCCCCC">Inclination:</th><th>33.3°</th></tr><tr><th bgcolor="#CCCCCC">Orbital Period:</th><th>~89 minutes</th></tr><tr><th bgcolor="#CCCCCC">Apoapsis:</th><th>242 km</th></tr><tr><th bgcolor="#CCCCCC">Periapsis:</th><th>150 km</th></tr><tr><th bgcolor="#CCCCCC">Orbits:</th><th>32</th></tr>

Ranger 2 <tr><td style="border-top:1px solid #999966; text-align: center;" colspan="2"> </td></tr>
Organization:	NASA <tr><th bgcolor="#CCCCCC">Major Contractors:</th><th>Jet Propulsion Laboratory</th></tr>
Mission type:	Lunar Science
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Instruments
Lyman-Alpha Telescope	to scan earth to study hydrogen constituent of exosphere
Magnetometer	to measure magnetic field in interplanetary space

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.

[edit] Spacecraft design

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.

[edit] Mission

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 November 20, 1961.

[edit] External link

Lunar impact: A history of Project Ranger (PDF) 1977

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