by NASA

“ In recent years, however, astronomers on earth have observed through their telescopes what appear to be gaseous emissions from the moon's interior. Erosion seems to be a significant force on the moon despite the absence of wind and water. It is theorized that incessant bombardment by meteoroids and by protons (particles of atoms) emanating from the sun may have pulverized the boulders, filled the fissures, and smoothed the edges of the less sharp secondary craters. Last picture by Ranger VII, taken about 1600 feet above the moon, reveals features as small as 15 inches across. ”

“ These photoelectric devices convert sunlight into 200 watts of electricity for powering spacecraft equipment. Auxiliary power is furnished by two silver zinc storage batteries which are used when the solar panels are not functioning, particularly during launch when they are still folded and during mid- course correction. During its flight, Ranger must be positioned so that its solar panels face the sun for power and its high-gain antenna points to earth. A complex system of sun and earth sensors, gyroscopes, and nitrogen gas jets keep the craft oriented. ”

“ Surveyor will telecast the moonscape, analyze lunar surface and subsurface materlal, measure moonquakes and meteorite impacts, and check the moon's surface for strength and stability. A third project, called Lunar Orbiter, is aimed at developing an unmanned spacecraft to be guided into a low-altitude lunar orbit, photograph the moon's surface, and provide more information on the moon's size, shape, and gravity. ”

“ While some areas are clearly unsafe for landing, others are believed to be sufficiently level and smooth for touchdown by the Apollo Lunar Excursion Module as presently designed; however, no knowledge of the surface strength could be obtained from the Ranger photographs. RANGER VII is the first of the Ranger series of spacecraft to provide close-up photographs of the moon. ”

“ The pictures gave no fine detail, but did indicate that possibly the moon's hidden portion may not be as rugged as the area visible from earth.
THE MOON Although many lunar features are beyond the reach of his ground-based instruments, man does have significant facts: The moon's diameter is 2163 miles, about one-fourth that of earth. Its gravity is one-sixth that of earth, meaning that a 156-pound man on earth would weigh only 26 pounds on the moon. The moon's mean altitude in its elliptical orbit around earth is 238,857 miles. ”

“ The radio signals appear on the television sets as a dot of light moving across the screen. The camera lenses are set to stay open long enough to photograph the light through a complete sweep over the screen, By this means, the cameras make meaningful still photographs.
The Ranger "bus" is the basic vehicle to which the experiments (in this case, the television system) are attached. It contains Ranger's prin- cipal power supply; telemetry instruments to re- port on the spacecraft's condition and operation; a command system to enable personnel on earth to control the craft ”

“ Just as the Rosetta Stone gave the first clue toward deciphering Egyptian hieroglyphics, study of lunar material may help answer key questions regarding the origin and evolution of the solar system and perhaps how life may have begun. ”

“ North is at top.
Altitude: 34 miles. Area: 16 miles on a side. Smallest Visible Crater: About 150 feet in diameter. Features: Greater resolu- tion of craters in outlying ray of Tycho. THE RANGER TELEVISION SYSTEM The remarkably clear pictures of the moon telecast by Ranger VII were accomplished by a complex high quality system of television cameras and transmitters on Ranger and a ground receiv- ing network at the Goldstone, Calif., station of NASA's global Deep Space Network. This network tracks, controls, and gathers information from NASA spacecraft sent to the moon and beyond. ”