Ranger 1

From Wikipedia, the free encyclopedia

Ranger 1
Ranger 1
Organization NASA
Major contractors Jet Propulsion Laboratory
Mission type Lunar Science
Satellite of Earth
Orbits 110
Launch date August 23, 1961 at 19:12 UTC
Launch vehicle Atlas-Agena B
Mission duration 7 days
Decay August 30, 1961
NSSDC ID 1961-021A
Webpage NASA NSSDC Master Catalog
Mass 306.2 kg
Orbital elements
Semimajor axis 6,690.3 km
Eccentricity .019939
Inclination 32.9°
Orbital period 91.1 minutes
Apoapsis 446 km
Periapsis 179 km
Instruments
Lyman-Alpha Telescope to scan earth to study hydrogen constituent of exosphere
Magnetometer to measure magnetic field in interplanetary space

Ranger 1 was a spacecraft in the Ranger program whose primary mission was to test the performance of those functions and parts necessary for carrying out subsequent lunar and planetary missions. A secondary objective was to study the nature of particles and fields in interplanetary space.

[edit] Spacecraft design

The spacecraft was of the Ranger Block 1 design and 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 solar X-ray scintillation counters.

The communications system included the high gain antenna and an omni-directional medium gain antenna and two transmitters, one at 960.1 MHz with 0.25 W power output and the other at 960.05 MHz with 3 W power output. Power was to be furnished by 8680 solar cells on the two panels, a 57 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, and pitch and roll jets. The temperature was controlled passively by gold plating, white paint, and polished aluminum surfaces.

[edit] Mission

The Ranger 1 spacecraft was designed to go into an Earth parking orbit and then into a 60,000 by 1,100,000 km Earth orbit to test systems and strategies for future lunar missions. Ranger 1 was launched into the Earth parking orbit as planned, but the Agena B failed to restart to put it into the higher trajectory, so when Ranger 1 separated from the Agena stage it went into a low Earth orbit and began tumbling. The satellite re-entered Earth's atmosphere on August 30, 1961. Ranger 1 was partially successful, much of the primary objective of flight testing the equipment was accomplished but little scientific data was returned.

[edit] External links