NATIONAL AERONAUTICS AND SPACE ADMINISTRATION I - NF-3UVOL. IV , NO. 4 . -.-- Lunar QrbiIes BLAZING A TRAIL FOR MAN TO FOLLOW By the end of this decade, American astronaut- explorers are scheduled to land on the moon. Lunar Orbiter is one of three unmanned space- craft programs undertaken to help select sites for these manned landings and, at the same time, to gather and report basic scientific data which cannot be obtained by observations from earth. The other two: Projects Ranger and Surveyor. The Lunar Orbiter project was managed by NASA’s Langley Research Center, Hampton, Virginia, for the Office of Space Science and Applications, NASA Head- quarters. Lunar Orbiter spacecraft were placed into rela- tively low orbits around the moon to take sharp close-up photographs of extensive areas. The photo- graphs are primarily for use in selecting sites for manned landings and in increasing our scientific knowledge of the moon’s surface. In addition, the spacecraft are providing information about the moon’s size, shape, and gravitational field and about radiation and micrometeoroids (tiny par- ticles of matter in space) in the moon’s vicinity. In a closely coordinated effort, NASA Surveyor spacecraft were soft-landed on the moon. As an example, Surveyor I which landed gently in the Ocean of Storms on June 2, 1966, transmitted pictures and other information about the lunar sur- face in its general vicinity. These were coordinated with the more extensive overhead views from Lunar Orbiter I launched August 10, 1966. Earlier, c ! . . . 1Close-up of part of the vast Crater Copernicus taken by th e camera of Lunar Orbiter 1 1 . Mountains rise as high a s 1000 feet from the crater floor. Horizontal distance: about 17 miles. Distance from base of photograph to horizon: about 150 miles.
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2 Lunar Orbiter I photograph of area whereSurveyor I landed. The area was shown bypictures from both spacecraft t o be relativelysmooth. Center coordinates are 43" W.Longitude; 2" 20 ' s . Latitude. Note mountainswhich appear as white areas at north (top).
together. In the background are crests of the
mountains photographed by Lunar Orbiter I inanother illustration on page 2.
4 A large crater is superimposed on part of anolder smaller crater in this Lunar Orbiter Iphotograph of the side of the moon never seenfro m earth. The larger crater is about 31 milesacross.
3 Two pictures f rom Surveyor I are pieced
5 Possible manned landing sites which LunarOrbiters I and II photographed at close range.
9 Orbiter I photograph of rugged area just westof Crater Landsberg. Area is 25 x 29 miles.Center coordinates: 30 " 45 ' W. Longitude and1 " 45' N. Latitude.
i o Lunar Orbiter I view of the m oon's eastern limb(edge), which is the right side relative to an
observer on earth. This region is rarely seenfrom earth. Area covered: about 106 x 89 miles.Approximate location: 90" E. Longitude; 0"
Latitude.
11 Dual-frame photographs taken by Lunar Orbiterappear as indicated in sketch above.
inch.) in d iameter . The t iny l ig ht spot t ravels back
and fo r th across the one- ten th inch o f f i lm, mak ing
some 17,000 passes (scan l ines) to read out the
width o f the f i lm. The f i lm is advanced after each
scan, and the process repeated.The l ight beam passes through the negative
on to a pho tomul t ip l i e r tube. Th is converts the l i gh t
str ik in g i t in to a vary ing electric curren t that c orre-
sponds to the l i gh t and dark a reas on the negat ive .
For example, the darker areas of the negative re-
duce the amount o f l i gh t tha t can pass th rough.
The e lectr ica l current is then fed t o an ampl i f ier
and to the spacecra f t ' s rad io wh ich t ransmi ts the
i n fo rma t i on to ea r th .
PICTURE SIGNALS PICKED UP AND
PROCESSED ON EARTH
The 85- foo t -d iame ter an tennas of NASA's Deep
Space Network keep in constant touch wi th O rbi ter :
commanding i ts maneuvers, moni tor ing i ts condi -
t i on , t rack ing it , and acqu i r ing i ts p i c tu re and o ther
scient if ic data. The great antennas p ick up the
fa int s ignals (down to about a b i l l ionth watt of
power) received from Lunar Orbi ter and ampl i fy
them to useful strength. They relay the signals t o
magnetic tape recorders and to kinescopes, which
are somewhat l ike the p icture tubes in home te le-
19 Lunar Orbiter V snapped this photograph ofth e Crater Tycho, located at 1 1 " West
Longitude and 43" South Latitude on the moon.Tycho is about 50 miles from rim to rim. Note
the central peak, a characteristic of manylarge lunar craters.
20 While circling the moon, on August 8, 1967
Lunar Orbiter V snapped this first picture ofa nearly full earth. Clearly visible are Africa, theEastern Mediterranean area, and the Arabian
Peninsula. A part of the Indian Peninsula maybe seen through the clouds which obscure much
of Asia and the Indian Ocean.
21 The meandering Prinz Valleys I and II,running downhill, are among the major
features of this Lunar Orbiter V photograph of
the moon's Harbinger Mountain area. Somescientists attribute these valleys t o volcaniceruptions and the flow of fluidal material. At
left is Prinz Valley II, 8,000 feet wide at itshead (below) and narrowing to about 1,500 feet
near it s end. To i ts right i s Prinz Valley I.
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