LUNAR ROBOTIC PROBES L U N A R R O B O T I C P R O B E S (Pioneer, Ranger, Surveyor, Lunar Orbiter) From its beginning NASA has been interested in the scientific study of the Moon and planets. In 1961 it had the added responsibility of securing lunar information that would be needed for a manned expedition to the Moon. P I O N E E R Pioneer was chosen as the name for the first U.S. space probe, a series initiated for the International Geophysical Year by the Department of Defense. Like the Explorer* series, NASA inherited the responsibility for the probe and kept its name. * Explorer series of satellites under NASA were launched from 1959 - 1975. The first eight were designed as lunar probes. Because of launch vehicle failure, the program met with little success--only Pioneer 4 reached the Moon--but Pioneer 1 discovered the radial extent of the radiation belts, Pioneer 2 returned data about the atmosphere, and Pioneer 3 discovered the second radiation belt. PIONEER 4 March 1959 Measured particles and field in a flyby of the Moon. entered a heliocentric orbit. R A N G E R The Ranger program was a probe series to transmit close-up black and white photographs of the Moon before crashing into the Lunar surface. Three of the nine Rangers (7,8,9) were successful. Rangers 1 through 5 experienced technical problems which affected the success of the missions: the launch vehicles malfunctioned for Ranger 1 and 2, Rangers 3 and 5 missed the Moon, and Ranger 4 landed on the back side of the Moon and returned no data. Ranger 7, 8, 9 findings: A gently rolling terrain with no sharp relief; and a layer of powdery rubble, with rocks and craters down to at least one meter in diameter everywhere. RANGER 6 January 30 - February 02, 1964 Lunar impact point of hard landing within 32 km (20 mi) of target. TV system failed to operate. RANGER 7 July 28 - 31, 1964 First successful Ranger mission. 4,316 high resolution TV pictures of the lunar surface were returned, with objects less than .9m (3 ft) discernible. Impact on Sea of Clouds 13-16 km (8-10 mi) from aim point. Flight time: 68 hours, 36 minutes. RANGER 8 February 17-20, 1965 7,137 pictures returned from Sea of Tranquillity. Flight time: 64 hours, 63 minutes. RANGER 9 March 21-24, 1965 5,814 pictures of Crater Alphosus and vacinity returned. 4.8 km (3 mi) from target. Flight time: 64 hours, 31 minutes. S U R V E Y O R Following the Ranger hardlandings, from 1966 - 1968, the Surveyors series was conducted to softland unmanned spacecraft on the Moon, survey it with cameras, and analyze the chemical composition of the lunar surface. Five of the seven Surveyors were successful. They operated on the lunar surface over a combined time of 17 months, transmitted more than 17,000 pictures, and made analyses of surface and subsurface samples. SURVEYOR 1 May 30 - June 02, 1966 Successful soft landing in Ocean of Storms. 11,237 pictures returned; found that the surface is firm and capable of supporting machines and astronauts. SURVEYOR 3 April 17 - 20, 1967 Landed in the Sea of Clouds and returned 6,315 pictures. First soil scoop. Piece of the spacecraft brought back by Apollo 14. SURVEYOR 5 September 08 - 10, 1967 Soft landing in the Sea of Tranquillity. Returned over 19,000 pictures. First alpha scatter instrument analyzed chemical composition and found that the surface of the maria resembles that of terrestrial basalt lava. SURVEYOR 6 November 07 - 10, 1967 Soft landing in the Central Bay region. Returned 30,065 pictures. First lift-off from lunar surface moved it ten feet to new location. SURVEYOR 7 January 07 - 10, 1968 Successful soft landing on ejecta blanket adjacent to Crater Tycho. First combination of the three major experiments: TV, alpha scatter, and surface sampler. Found that the highlands composition differs from that of the maria and is aluminum-rich. LUNAR ORBITER Final unmanned lunar program. The Orbiters worked in conjunction with the Surveyor to acquire photographic and scientific data in preparation for the Apollo landings. All five Lunar Orbiters were successful. They made more than 6,000 orbits of the Moon and photographed more than 99 percent of the lunar surface. The first three provided sufficient coverage for selection of eight candidate sites for Apollo, the fourth supplied detailed coverage of the front side of the Moon, and the fifth supplemented data provided by the others. At the end of their lifetimes, all were commanded to impact the Moon so as not to interfere with manned spacecraft. LUNAR ORBITER 1 August 10, 1966 First U.S. spacecraft to orbit another planetary body. Returned medium and high resolution photos of nine primary and seven potential Apollo landing sites; crashed on Moon, October 29, 1966. LUNAR ORBITER 2 November 06, 1966 Returned 211 frames (422 medium and high resolution pictures); crashed on Moon, October 11, 1967. LUNAR ORBITER 3 February 05, 1967 Returned 211 frames including photographs of Surveyor 1; crashed on Moon, October 09, 1967. LUNAR ORBITER 4 May 04, 1967 Returned 163 frames; crashed on Moon, October 06, 1967 LUNAR ORBITER 5 August 01, 1967 Returned 212 frames including five Apollo sites, and provided near-lunar micrometeoroid data. Crashed on Moon, January 31, 1968. --- NASA, The First 25 Years, 1958-1983, A Resource for Teachers, EP-182