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.
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NASA, The First 25 Years, 1958-1983, A Resource for Teachers, EP-182