The area of Mare Tranquillitatis in which Surveyor 5 landed appears to be similar to sites in Oceanus Procellarum. The gross elemental composition of the surface material and its response to a magnet are similar to those of a basalt. The debris layer appears to consist of aggregates of the order of 1 cm in diameter consisting of fine grains and set in a matrix of less-coherent fine grains (most of them 2 to 60 μ in diameter) mixed with some rocky fragments 1 mm and larger. The static bearing strength is less than 10^4 dynes/cm^2 for the upper few millimeters and averages approximately 3 × 10^5 dynes/cm^2 for the upper few centimeters. The evidence suggests that chemical differentiation has occurred in the moon, probably owing to internal heat sources; this is consistent with the hypothesis that the maria are basaltic volcanic flows

Batterson, S. A.

Brown, W. E., Jr.

Christensen, E. M.

Dwornik, S. E.

Gault, D. E.

Jaffe, L. D.

Lucas, J. W.

Norton, R. H.

Scott, R. F.

Shoemaker, E. M.

Sutton, G. H.

Turkevich, A. L.

Caltech Authors - Main

JOURN^t. oF GF. OVH¾S•CAL RESF•ARC}• VOL. 73. No. 22, NOV•-MB•-R 15, 196g 
Principal Science Results from Surveyor 5 
L. D. JAFFE, 1S. A. BATTERSON, 2 W. E. BaowN, Ja., 1 E. M. CHRISTENSEN, 1 
S. E. DWORNIK, 3 D. E. GA!JLT, 4 J. W. L!JCAS, 1 P•. I-I. NORTON, 1 R. F. SCOTT, 5 
E. M. SHOEMAKER, 6 G. I-I. SUTTON, 7 AND A. L. T!JRKEVICH 8 
The area of Mare Tranquillitatis in which Surveyor 5 landed appears to be similar to sites 
in Oceanus Procellarum. The gross elemental composition of the surface material and its 
response to a magnet are similar to those of a basalt. The debris layer appears to consist of 
aggregates of the order of I cm in diameter consisting of fine grains and set in a matrix of 
less-coherent fine grains (most of them 2 to 60 t• in diameter) mixed with some rocky frag- 
ments I mm and larger. The static bearing strength is less than 104 dynes/cm 2 for the upper 
few millimeters and averages approximately 3 X 105 dynes/cm 2 for the upper few centimeters. 
The evidence suggests that chemical differentiation has occurred in the moon, probably owing 
to internal heat sources; this is consistent with the hypothesis that the maria are basaltic 
volcanic flows. 
The area of southwestern Mare Tranquillitatis 
in which Surveyor 5 landed appears generally 
similar to the sites in Oeeanus Proeellarum 
observed by Surveyors 1 and 3. All three areas 
are fairly level dark maria with rather similar 
distributions of craters and rocks. A surface 
layer of weakly cohesive fine particles, aggre- 
gates, and rocks is present in both Mare Tran- 
quillitatis and Oeeanus Proeellarum. Differences 
between the surface layers in these maria are 
relatively small. 
Surveyor 5 was the first soft-landing lunar 
spacecraft to obtain information about the 
chemical nature of the hmar surface. This infor- 
mation was obtained through two experiments, 
one giving the gross chemical composition by 
an a-particle backscattering instrument, and 
• Jet Propulsion Laboratory, California Institute 
of Technology, Pasadena, California 9,1103. 
2 Dynamic Loads Division, NASA Langley Re- 
search Center, Hampton, Virginia 23361. 
a NASA Headquarters, Washington, D.C. 20546. 
• Planetology Branch, Ames Research Center, 
Moffet Field, California 94035. 
5 Division of Engineering and Applied Science, 
California Institute of Technology, Pasadena, Cali- 
fornia 91109. 
• Branch of Astrogeology, U.S. Geol•)gical Sur- 
vey, Flagstaff, Arizona 86001. 
* Itawaii Institute of Geophysics, University of 
Itawaii, Honolulu, Hawaii 96822. 
8 Enrico Fermi Institute for Nuclear Studies and 
Department of Chemistry, University of Chicago, 
Chicago, Illinois 60637. 
the other giving some magnetic characteristics 
of the surface material with a bar magnet. 
The three most abundant elements found by 
Surveyor 5 at the mare landing site are the 
same as the most prevalent on the surface of 
the earth; in decreasing abundance, they are 
oxygen, silicon, and aluminum. The relative 
amounts of the chemical elements are similar 
to the amounts in a silicate rock of a basaltic 
type. 
Lunar surface material of high magnetic sus- 
ceptibility adhered to the magnet. The quantity 
of magnetic material observed on the mag- 
net is comparable to that expected if the mag- 
net came in contact with pulverized basalt with 
10 to 12% magnetite and not more than 1% 
admixed metallic iron. Particle size of material 
attracted by the magnet was less than 1 mm. 
Surveyor 5 landed in a dimple-shaped, 9- 
X 12-meter rimless crater, which is the largest 
member of a small chain of rimless craters; a 
parallel row of very small craters also occurs 
within the large crater. The long axis of the 
large crater and the crater chain are approxi- 
mately parallel with the dominant linear fea- 
tures in the highlands west of Mare Tranquil- 
litatis and with many other elongate craters 
and crater pairs in nearby parts of the mare. 
On the basis of its shape and the alignment of 
small associated craters, the crater in which 
Surveyor 5 landed may have been formed by 
drainage of surfieial fragmental debris into a 
northwest-trending fissure. 
7165 
7166 
Observations of blocky rimmed craters, rela- 
tively nearby, indicate that the local thickness 
of the layer of fragmental debris with low co- 
hesion is not more than 5 meters. The walls of 
the Surveyor 5 crater provide exposures of the 
upper meter of this debris layer. •Different ypes 
of fragments are revealed in the pictures of 
the debris dislodged from the walls during the 
landing and in the pictures of the undisturbed 
parts of the wall. The types of fragments in- 
elude: 
1. Bright, angular objects, which are in- 
ferred to be pieces of dense, rocky material. 
2. •Dark, rounded objects, which are prob- 
ably aggregates of very fine-grained particles. 
3. ])ark, lumpy objects, which appear to 
be aggregates of aggregates. 
The aggregate character of some of the loose 
ejected fragments is well demonstrated by the 
presence of bright angular chips set in a dark 
fine-grained matrix. At depths greater than 
about 10 cm, most of the debris layer appears 
to be composed of slightly compressed aggre- 
gates, ranging from a few millimeters up to 3 
cm in diameter, set in a matrix of less-coherent 
finer particles. Rocky chips and fragments 
larger than a millimeter are dispersed as a 
subordinate constituent of the debris. 
The estimated normal albedo (normal lumi- 
nance factor) of the undisturbed parts of the 
lunar surface near Surveyor 5 is 7.9 ---+ 1.0%, 
somewhat lower than observed at the Surveyor 
3 landing site. Debris ejected on the lunar sur- 
face in front of the footpads has a normal 
albedo of 7.5 _4- 1.0%, which is only about one- 
twentieth lower than the albedo of the undis- 
turbed surface but is similar to the albedo of the 
material disturbed by the footpads at the Sur- 
veyor 3 landing site. 
New photometric evidence obtained from the 
Surveyor 5 pictures shows that the bright an- 
gular fragments are denser or at least less 
porous than the dark fine-grained surficial ma- 
terial and dark aggregates. The surfaces of the 
bright angular fragments have a photometric 
function more like that of a lambertian scat- 
terer than like that of the fine-grained lunar 
material. 
A spacecraft vernier engine firing against 
the lunar surface produced observable erosion 
resulting from two mechanisms' the removal 
JAFFE ET AL. 
of particles by exhaust gases blowing along the 
surface, and explosive blowout of entrapped gas 
and soil from directly beneath the nozzle im- 
mediately following engine shutdown. Analyses 
of the disturbance indicate the material has a 
permeability to gases of between I X 10 -8 and 
7 X 10 -8 cm •', which is comparable to the per- 
meability of terrestrial silts. 
As for Surveyors i and 3, the landing pro- 
duced interactions with the surface. Various 
analyses of phenomena ssociated with the land- 
ing and with the firing of the vernier rocket 
engines have provided these additional esti- 
mates of surface properties. 
Static bearing strength: 
For upper few millimeters, <104 dynes/cm 2. 
Averaged over upper few centimeters, •3 X 
105 dynes/cm 2. 
Angle of internal friction: consistent with Sur- 
veyor 3 results (37ø). 
Pressure developed by the soil against he foot- 
pad in resisting the slide during landing was 
about 7 X 104 dynes/cm •', which agrees with 
results obtained from the soil mechanics surface 
sampler experiment on Surveyor 3. The esti- 
mate of permeability indicates that most of the 
particles are in the 2- to 60-/• size range; this 
values agrees with results from photographic ob- 
servations of the disturbed areas, the match of 
Surveyor 5 footpad trenches to trenches pro- 
duced experimentally in pulverized basalts, and 
analyses of Surveyor 3 footpad imprints. Clods 
observed in the disturbed areas appear to be 
similar to the ones observed in previous mis- 
sions, indicating a similar cohesion. I  general, 
the soil at this site appears similar to, but some- 
what weaker than, the soil at the other Surveyor 
landing sites. 
The lunar day temperatures derived from 
Surveyor 5 observations are in fair agreement 
with predictions based on telescopic observa- 
tions. The temperatures of the lunar surface 
after sunset and during total eclipse suggest 
that the surface material has an effective re- 
ciprocal thermal inertia of approximately 500 
cm •' sec '/2 øK/g cal, in good agreement with Sur- 
veyor 3 eclipse data. This value differs from 
a value of approximately 1000 obtained from 
data derived on earth. 
The evidence that the lunar surface material 
at the Surveyor 5 landing site is basaltic in 
composition and the fact that this Surveyor 5 
SURVEYOR 5--PRINCIPAL SCIENCE RESULTS 7167 
site appears to be typical of the mare areas are 
consistent with the hypothesis that the mare 
basins are filled with extensive basaltic volcanic 
flows. If such flows have occurred, some of the 
processes and products of lunar magmatic ac- 
tivity are apparently similar to those of the 
earth. The results suggest that differentiation 
has occurred in the moon, probably owing to 
internal sources of heat. 
Surveyor 5 provided the first measurements 
of the brightness of the solar corona (the F 
corona) at distances of 10 to 30 solar radii from 
the center of the sun. Since the brightness is 
produced by the scattering of particulate matter 
between the earth and the sun, it should prove 
possible to derive density measurements of par- 
ticulate matter at distances out to one-third the 
radius of Mercury's orbit. A good determination 
of the density distribution with height above 
the ecliptic plane can be made. 
(Received March 29, 1968; 
revised July 15, 1968.) 


Principal science results from Surveyor 5

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Principal science results from Surveyor 5

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