Voyager 2 at Saturn—Early Findings
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Transcript of Voyager 2 at Saturn—Early Findings
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( H A S A - T f l - 8 4 0 9 1 ) V O Y A G E S 2 A T S A T O B N : E A f l L Y
F I N D I N G S (National Aeronautics and SpaceAdministration) 11 p
-7 1775
I
Report
00/91Unclas07568
V o l . 9, No. 3 Fall 1981
Voyager 2 at Saturn—Early Findings
O n A u g u s t 2 5th, 2 . 7 seconds early and on ly 30 miles from
th e ai m point, Voyager 2 ended it s four-year journey to
Saturn w it h a second spectacular view of the planet. Its
imag es equalled those of Voyager 1 and its experiments
provided an abundance of riches w it h new data.
T a ki n g a dva n ta ge of kn ow l e dge ga i n ed from th e Voya ge r
1 flyby, Voyager 2 's instru men ts were adjusted to
concentrate on selected targets: a closer study of the planet's
atmospheric motion, the rings, five of the near and seven of
the new satellites, and the magnetosphere. I ts path took it
23,000 kilometers closer to the planet than Voyager 1 and it
approached from above the r i n gs , w i t h the Sun behind it .
The resul tant photographic con ditions were superb and,
along with better cameras that produced sharper images,
allowed the spacecraft to send back remarkably detailed
pictures.
The early resul ts were stu nnin g.
Au g u s t 2 3. 1981. S atu rn ' s C R i n g from a distance of 2.7 million ki lom eters .
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The Atmosphere. The placid, bland-looking Saturn seen
through a telescope w as shown by Voyager 1 to be a sphere
of many colored bands, violent weather storms, jet streams,
high and low pressure systems.
Voyager 1 passed under the South Pole. Voyager 2
imaged more of the planet covering th e northern hemisphere
up to the N orth Pole, an d showed th e formation of bands
an d clouds that circle it in much greater detail. This second
look at the turbulent atmosphere revealed new features:
clouds vortices (small hurricanes), high-speed jet streams,
an d eddies evident at higher latitudes (up to 8 0 ° N ) ; a train of
vortices at about 40°N; and a curious cloud system that
curled into a figure 6.
Saturn is cold. Voyager 2 's infrared interferometer
spectrometer data show that its temperature ranges from
80°K to 95°K at the cloudtops. However, th e planet still
radiates almost 2.5 times as m uch energy as it receives from
th e Sun. Saturn 's upper, or outer, atmospheric mass is 89%
hydrogen w ith most of the remaining 11 %, helium. This is
much less helium than has been measured in Jupiter's
atmosphere (19%), an d lends credence to the theory that onSaturn the helium, which is heavier than hydrogen,
separates out and sinks toward the center of the planet. The
separation process provides a source of heat. Traces of
ammonia, phosphi n e , methane, and other hydrocarbons
have also been detected in its atmosphere.
Th e Rings. Before last fall, it was believed there were fiverings about Saturn. Voyager 1's cameras showed hun dre ds .
Voyager 2 's photographs have revised th e c oun t to
thousands. Both spacecraft showed the ring system as
complex and mysterious.
Areas of concentrated study by Voyager 2 were the B
Ring and its spokes, th e braided F R i n g and its satelli tes,
the eccentric rings (C Ring and one in the Cassini Division)
and the Encke Div ision , and a photopolarimeter observation
of the rings.
Voyager photographed the A, B, C, and F R i n g s an d
re-verified the existence of and photographed the D and G
Rings; the E Ring was detected by the fields and particles
instruments.
Voyager 2 's observations tested several theories of the
rings' stability, what mechanism is holding the ring
panicles in orbit around th e planet . O ne theory supposes
that the ring particles are in resonance with one of the larger
satellites, and some of the larger gaps in the rings do occur
at distances corresponding to orbital resonances with Mimas
(in a 2 :1 resonance, the particles m ake tw o orbits for everyone orbit by Mimas; M imas also exerts a gravitational pu ll).
A second theory proposes that small moonlets herd each
ringlet; th e imag ing cameras searched the rings for evidence
of new moonlets, bu t none were fou nd beyond those already
k n o w n in the F R i n g . A third theory proposes density waves
•o3
-• 30
-200 -100 100 200 300
Wind Velocity (meters/sec)
Wind velocities plotted on a photograph of Saturn 's northern hemisph ere. A westward-flowing wind current appears to drive a wedge through a train ofvortices (small hurricanes) with obvious eastward streams above an d below. As the vortice separates, smaller cyclones are formed. Those to the north
route clockwise, to the south, counterclockwise. This is one of the many interesting phenomena observed by Voyager 2 .
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Saturn's northern hemisphere in a photograph taken on A u g . 2 1 from a dis tan ce of 5.4 million km shows weather patterns at all latitudes. A stream ofclouds attached to a large spot about 3000 km in diameter is moving westward at about IS meters pe r second; th e spot moves eastward at about 10 meterspe r second and shows counterc lockw ise rot ation. The ribbonlike feature in the latitude band centered at 47°N marks a high-speed jet of about 150 meters
pe r second. Further small scale clouds are evident toward the polar region.
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in th e ring particles an d some evidence of such waves is
seen in Voyager data. A fourth theory involves collisions
between the ring particles themselves, though a narrow ring
says that something is preventing collisions.
Photopolarimeter experiment A spectacular an d ambi-
t ious experiment used a device called a photopolarimeter.
During approach it locked on a single star, Delta Scorpii,
an d measured th e star's light as it filtered through the ringsto gather information about the rings' composition an d
structure. The results were highly successful, providing a
t remendous amount of detailed data. Analysis of the data
will yield a map of an area the size of the U.S. with the
resolution of a city block.
The main ring system extends from near th e planet out to
about 75,000 km above the cloudtops, a vast sheet of icy
debris varying in thickness, composit ion, an d orbital
characterist ics. W ith resolution down to a city block—about
15 0 meters—the photopolarimeter's data present ne w
questions: where does one ring end and another begin?
what is the shoulder of one ring or the body of another? Th ephotopolarimeter found evidence of pressure waves w hich
ar e responsible for changes in the thickness of the ringlets
( thus , they have so-called "shou lders"). M any of the
ringlets ar e non-circular, indicating that structure changes
rapidly, perhaps continuously, in the rings.
B Ring Th e mysterious finger-like structures Voyager 1
found in the B Ring received a great deal of attention from
Voyager 2 , including some special ring plane crossing
photographs and a series of time-lapse movies to s tudy their
formation an d l ifespans. The spokes form over very short
time periods (m inu tes ), primarily near th e point where th ering particles emerge from Saturn 's shadow. Most dissipate
before completing a single orbit of the planet, bu t some
remnants do persist an d other spokes form on top of t h e m .
The spokes form radially (they extend outward from th e
planet like spokes in a wa gon whe e l) and are seen on both
faces of the rings, north an d south ( i l luminated an d
unilluminated, but the features on the unli t side could
possibly be shadows of spokes). O ne theory proposes that
the spokes are electrostatically-levitated particles of fine
dust lifted above the plane of the rest of the B R i n g by
Saturn's magnetic field l ines which pass throug h the B Rin g
in th e spokes region. Three pictures were taken during ring
plane crossing when the rings could be viewed nearly
edge-on in hopes of seeing this phe n ome n on , w i t h th e most
F or several days in late August, a large vortex in Saturn's northern mid-latitudes unfolded an d Voyager 2 recorded it s progress. In i t ial ly
corkscrew-shaped, over a period of seven rotations it became more like a "6" and eventually formed a closed loop. Such studies give clues to the planet 's
atmospheric dynamics.
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spectacular picture '/2 degree above the plane. How ever, no the satellites w hich could have caused the peculiar braid in
evidence of particle levi tation could be seen from any of
these pictures.
F Ring An analysis of the imagery of the F R i n g and its
shepherding s atellites revealed no satellite effects on the
ring s tructure, no ring perturbations due to the presence of
seen by Voyager 1.
Encke Division Voyager 2 discovered a new "kinked
ring inside the Encke Division that looks similar to the
R i n g . Seen as close as a 15-km resolution, the new ring ha
no satellites.
Herding th e thin F R ing between th em, satelli tes 1980S27 ( inner) and 1980S26 (ou ter) are about 1800 km apart in this image. Traveling s ligh tly faster, thinside moon overtook the outer one about two hours later, a lapping that occurs every 25 days.
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e Satellites. Saturn's 17 satellites fall into three maingiant Titan, seven intermediate-sized icy satellites,
d eight small moonlets. Phoebe, the outermost satellite,a fourth class, captured asteroids.
Voyager 2 flew closer and took higher resolution
of Enceladus, Tethys, Hyperion, lapetus, an dthan did Voyager 1. It also photographed seven of
e planet's new ly discovered satellites.
Enceladus Th e closer look at Enceladus showed a variedflat plains seen earlier, bu t also craters,
valleys, which suggest an active geologic past.which would be water
volcanoes since the satellite is comprised mostly of ice.Scientists believe the moon's age ranges from 10 0 million
years old in some parts to a few billion years old in others.
Tethys Two distinctive features have been found onTethys: a chasm several k ilometers deep, 100 km w ide, and2000 km long circling nearly three-fourths of its circumfer-
ence, and the largest crater in the Saturnian system. Thecrater is about 400 km in diameter, several kilometers deep,
and so large that the satellite Mimas could fit within it.
Hyperion An enigma. Hyperion is one of Saturn'soutermost moons, some 1,440,000 kilometers away from
high-resolution image of Enceladus made from several images taken by Voyager 2 on A u g . 2 5 from a range of 119,000 km .
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I
This series of pictures of Tethys shows its large crater, 400 km in diameter. Three views of Hyperion taken (from top) from 1.2 million km , 700,0as it rotates toward th e termination an d limb of the satellite (to the right). km, and 500,000 km , show th e changing aspect of the satellite.
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by wi thi n 480,000 kilometers, Voyager
clearly showed it to have th e shape of a squa t c yl in de r .
360 x 325 x 200 km, Hyperion was likened to an
to scientists. Voyager 1's images were uninteres t-
but now a pock-marked surface with a 96-km-wide
is evident. Th e huge crater could be the result of a
left it not only out of shapet also disoriented in relation to Saturn. Th e longest axis of
to the planet it is
bu t Hyperion travels around Saturn with it s long
lapetus and Phoebe lapetus isequally mysterious. It has
bright and a dark face, the greatest contrast of any object
th e solar system. I ts dark side, as black as asphalt, faces
orbit around Saturn. Tw o theories compete
an expla natio n: the black coat is thick and comes from
interior, or it is external in origin and lapetus is
dus tPhoebe.
O n Sept. 4 Voyager made its closest approach to Phoebe,
wi thi n 2.2 million kilometers to provide our first
this will support th e theory that lapetus' dark side
developed from an a c c umula t ion of particles in the
atmosphere.
There is evidence that Phoebe, S atu rn's out ermo st
satellite, is a captured asteriod. Observations show that it is
about 2 00 kilometers in diameter, is darker than an y other
of Saturn's satellites, and has a rotation period of 9 to 10
hours. It is the only Saturn satellite that does no t a l w a y s
show the same face to the planet. O rbiting Saturn every 550
days in the ecliptic plane rather than in the equatorial planeas do the others, Phoebe's orbit is retrograde, in the
direction opposite to that of the other satellites .
N ew Satellites V oya ge r 2 took high -resolu tion photo-
graphs of seven of S a t u r n ' s n e wl y discovered satellites:
1980S26 an d 1980S27, th e pair that shepherds the F R i n g :
1980S6, the satellite that occupies D ione's orbit; 1980S 1
an d 1980S3, the two moons that share an orbit; an d
1980S25 and 1980S 13, the tw o satellites recently discov-
ered in Earth observations that orbit Saturn about 60 degrees
behind and ahead of Tethys.The s even appear to be irreg ularly-s haped and heavily
cratered by impacts wi th cosmic debris. They range in size
from 96 to 320 kilometers across. 1980S3 appears to be
irregular an d heavily battered. Scientists believe it and
1980S 1 are tw o ha lve s of a satelli te that w as split in to tw o.
of Saturn 's small satelli tes ar e s hown in thi s composite of Voyager I and 2 im ag es . Ju s t 50 km separate th e orbits of I980S3 an d 1980S I. the
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Magnetosphere. Voyager 2 discovered a doughnut-shapedplasma torus around Saturn; w ith temperatures from 600
million to over on e billion degrees Fahrenheit , it is the
hottest found in the solar system.
The torus encircles Saturn at an alt i tude ranging from
273,600 kilom eters above the planet's cloudtops to as hig h
as 724,000 km. Its temperatures are about 300 times hotter
than th e solar corona, an d twic e as hot as the torus Voyager
1 discovered in the magnetosphere of Jupi te r .
The Low-Energy Charged Particle instrument that madethe discovery is designed to measure fast ions and electrons
in th e magnetospheres of the planets and in the interplanet-
ary medium. The instrument can dist inguish several
charged particles and meas ure both the direction in w hich
th e high-speed particles are moving and their temperature.
Saturn is surrounded by a series of tori. The newly
discovered hot torus is comprised of ionized oxygen and
extends from about th e orbit of cnceladus to about halfway
between the orbits of Dione and Rhea. There it meets the
inner edge of the neutral hydrogen torus discovered by
Voyager 1 w hich extends beyond the orbit of Titan.
The Platform Problem. Voyager 2's mission at Saturn was
marred by one malfunction. Shortly after closest approach
th e spacecraft 's scan platform stuck while th e spacecraft
was in the planet's shadow and out of c ommun ic a t ion with
Earth. The platform holds th e narrow an d wide a n gle
cameras, th e infrared radiometer, ultraviolet spectrometer,
an d photopolarimeter instruments. O n A u g . 28 the platform
w as successfully moved by ground command; although
initial response w as hesitant an d s low, it s response ha s
steadily improved. If the response is not dependable at
U r a n u s , Voyager 2 's next destination, th e spacecraft itselfca n be moved to focus the platform.
Voyager 2's Legacy. Voyager 2's encounter w ith Saturn
has left over 11,000 images an d t r i l l ions of bits of data on
th e several properties of the planet, its rings, and its
satellites—a wealth of information that scientists will be
studying fo r years.
F or scientis ts , it s success was an exhilarating accom-
plishment. It allowed them once more to look at our
neighborhood in the un ive rse , to explore where w e l ive, an d
to learn more about our own sma ll wor ld . It is also a
challenge. T he e n o r m o u s a m o u n t . o f new informationbrought new Saturnian mysteries.
A trajectory correction on Sept. 2 9 refined th e
spacecraft 's flight path to Ura n u s , whe re it is scheduled to
make the first closeup encounter in January 1986. I t will
continue on for the first flyby of N e p t u n e in August 1989.
Educators Conference. As at Voyager 1's encounter with
Saturn, an Educators Conference w as hosted by the Office
of Education an d C o m m u n i t y R e l a ti o n s at the Jet Propulsion
Laboratory an d Ambassador College in Pasadena, A u g u s t
23-25. Benito Casados, Manager of the Office, guided
over 150 participants throug h a program that included
presentations on Voyager, spacecraft communications, an d
future astronomy programs, briefings during th e encoun-
ters, and a discussion of the "Shuttle at Work" by
Astronaut Robert A. R. Parker. A highlight of the
program was a tour of JPL with visits to several of the
laboratories.
New Leadership at NASA
N A S A ' s new Administrator, James M. Beggs, assumed
office on July 10 succeeding D r. Robert A. Frosch, w ho
served from 1977 until hi s resignation in January.
Mr. Beggs came to N ASA from General D ynamics
Corp., in St. Louis, where he was Executive Vice
President, Aerospace as well as a director. In 1968-69 he
served N AS A as Associate Adm inistrator for Advanced
Research and Technology, and from 1969 to 1973 served as
Und er Secretary of Transportation. His next position w as as
managing Director, Operations fo r S u m m a Corp. until he
joined General Dynamics in January 1974.A 1947 graduate of the U.S. Naval Academy, M r. Beggs
served w ith the N avy until 1954. The follo w ing year he
received a master's degree from th e Harvard Graduate
School of Business Administration. He holds an honorary
LL.D. degree from Washington and Jefferson College (PA)
an d an honorary doctor of engineering management degree
from Emb ry-R iddle Aeronautical Un iversity (FL). Mr.
Beggs also enjoys affiliation with several professional
organizations.
B eg g s Mark
Also on J u l y 10 Dr. Hans Mark w as sworn in as
N AS A's new Deputy Administrator. And Dr. Mark is also
returning to N ASA having served fo r several years as
Director of the Ames Research Center.
D r. Mark w as Secretary of the Air Force from July 1979
to February 1981 after serving as Air Force Under Secretary
from 1977. He received his bachelor's degree in physics
from th e University of California at Berkeley in 1951
and his doctorate in physics from MIT in 1954. His
professional career includes positions as research physi-
cist , profess or, and adminis trator at laboratories w ith both
insti tutions.
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1981 Science Fair Program
ISEF. A m o n g the attendees at the Voyager 2 E n c oun te r
educational conference were the eight N AS A award
winners who won the trip with their teachers at the
International Science and Engineering Fair in May.The
students who were awarded Honorable Mention at the ISEF
received a mounted photograph of the Space Shuttle
Columbia signed by the astronaut crew and John F.
Yardley, then Associate Administrator for TransportationSystems.
State and Regional Fairs. The directors of 214 state and
regional fairs requested N AS A's participation in their
programs this year. At each fair up to five w inners could be
cited fo r outstanding achievement in aerospace research. In
addit ion, several N AS A Centers provided special programs.
Three Centers scheduled one-day visits for the N AS A
award-winners in their respective geographic areas. A t their
own expense, th e students, accompanied by families or
teachers, visited th e Centers fo r onsite introductions to
N A S A projects and activities.For the 14th year the Goddard Space Flight Center,
Greenbelt, M D , welcomed their winners. O n J u n e 26, 21
students and their families from nearby states and the
District of Columbia, were introduced to GSF C and its
programs. A highlight was a lecture on "TheFun of Space
Science."
The Lewis Research Center in Cleveland, OH, honoredits science fair winners on July 13. Students and their
parents from four states, including distant Minnesota,
Science fair winners and their parents are briefed about th e operation of testcells 3 and 4 in the Lewis Research Center's Propulsion Systems
Laboratory.
enjoyed an introduction to LeR C's activit ies that includedvisits to the 10 x 10 Supersonic W ind Tu nnel, Solar Test
Field, and the Electronic Propulsion Lab.
High school students representing five of the Center's
seven-state service area, attended the Marshall Space Flight
Center's third annual Science Fair Winners' Conference on
June 2 6. Students, parents, an d teachers were briefed on
current research and development projects an d visited
MSFC laboratories where they talked with scientists an d
engineers. O ne student, who was recognized for herconstruction of a wind tunnel, was ready to work there
"right now."
Second Space Shuttle Student
Involvement Project
Th e second Space Shuttle Student Involvement Project
(SSIP) in which experiments from high school students
across the nation are chosen for possible use on future Space
Shuttle missions, ha s been announced. Th e project is a joint
venture of N A S A and the N ation al Science Teachers
Association (N STA ). Any student is eligible to enter th e
competition who is regularly enrolled in grades 9 through
12 in U.S. public, private, parochial, and overseas schools,
including U . S . civil an d military overseas estab lishm ents,
Puerto Rico, Guam, the Virgin Islands, and outlying U.S.
territories.
Students first will sub mit'propos als to their science
teachers to review for adherence to the rules of the
competition. Then eligible projects will be submitted to the
NSTA Re gion a l Directors by the Feb. 1, 1982 deadline.
Interdisciplinary teams of teachers, scientists, an d
engineers, selected by NSTA will review the proposals atten regional centers. Up to 20 students from each of the
regions will be selected as semifinal is ts . These semifinal is ts
an d their teachers will attend regional Space Shuttle
conferences at N A S A research centers where they will
present their proposed experiments before N AS A and
industry scientists, an d attend an awards ceremony.
From the 200 semifinalists, as many as 20 proposals will
be selected on the basis of scientific or engineering merit for
potential flight aboard th e Space Shuttle. These national
winners an d their teachers will attend a national symposium
at N AS A's K ennedy Space Center in late summ er of 1982.
Winning students, their teachers, and their schools willreceive commemorative medallions.
The ten national winners of the first SSIP competition
were announced in May (see Vol. 9, No. 2). With th e
assistance of N ASA consultants an d their corporate
sponsors, these students ar e currently reviewing their
experiments for actual Space Shuttle missions or other
accommodations as appropriate.
Teachers shou ld write to the N STA for an official entry
form, rules booklet, and supplementary material: Space
Shuttle In vo lvem ent Project, N ational Science Teachers
Association, 1742 Connecticut A venu e, N W ., Washington,
D C 20009.
10
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The Solar Terrestrial Environment SlideProgram
A 40-color s l i d e / 1 5 -m i nu t e audiocassette presentation titled
Th e Solar Terrestrial Environment has been produced by
th e Alabama Space an d Rocket Center, H un ts v i l i e . The
program includes a script and user's guide and is
appropriate for astronomy, Earth science, general science,
and space physics classes from the 6th grade to adult levels.
Through photographs and diagrams, the program ex-
amines the structure and dynamics of the solar terrestrial
environment, looking at in detail, the Sun and solar
phenomena, th e solar w i n d , th e magnetosphere, iono-
sphere, an d atmosphere. Th e program introduces th e
interactive processes that couple these components, pre-
sents auroras an d other effects of magnetic storms, an d
surveys th e recent history of explorations in the solar
terrestrial environment, including some of the unsolved
puzzles in current research.
The Solar Terrestrial Environment may be purchased
from th e Alabama Space an d Rocket Center, TranquilityBase, Huntsvil le , AL 35807; the cost is $12.95 plus $1.00
for postage an d handling.
To Worlds Unknown, New Planetarium
Program
The Hansen Planetarium, Salt Lake City, has designed andproduced a new program, To Worlds U n kn own , incooperation with N AS A's Education Services.
Written, directed, an d produced by Mark Littman, To
Worlds U nknow n is a voyage aboard the Space Shu ttle that
follows the paths of N AS A spacecraft to the planets an dtheir moons whose features have just recently been
unveiled.
Th e program is available to all U.S. plane tar i urns free of
cost. For inform ation, contact the Hansen Planetarium, 15
South State Street, Salt Lake City, UT 84111.
Frederick B. Turtle
Th e N A S A staff an d professional colleagues in the
educational com mu nity were saddened by the death of D r.
Frederick B . Tuttle in May. At the t ime of his death Dr.
T ut t le w as special assistant fo r education in N A S A ' sAcademic Affairs Division.
D r. Tuttle joined N ASA in 1963 to continue a career in
aerospace education that began in 1946 when he helped
develop the Civil Aeronautics A dminis tration's education
program. At N A S A he served fo r eight years as Director of
Educational Programs during whi c h t ime, in addition to
supervising th e national program in education, he was
responsible for th e development of many of the agency's
curriculum resource materials. In October, N A S A ' s
Exceptional Service Medal w as awarded pos thum ously to
D r. Tuttle in recognition of "his un sw erving devotion to the
principles of the education process and his absoluteU.S. GOVERNMENT PRIN TING OFFICE: 1981-361-166:125
dedication an d outs tanding accomplishments in g u id ing
N A S A ' s efforts to disseminate information related to
N A S A ' s activities and the results thereof to the education
community."
A native of New Haven, C onnect icut , an d graduate of
Yale university where he received both bachelor's an d
doctoral degrees, Dr. Tuttle's career included positions as
public school teacher, principal, an d superintendent as well
as dean an d director of graduate studies, summer sessions,
an d extension division of the State University of New York
at Plattsburgh.
In 1973 he received the Frank G . Brewer trophy for
outstanding service to aerospace education and in 1979, th e
Crown Circle award fo r aerospace education leadership.
Recent NASA Publications
NASA's Aircraft Energy Efficiency research an d technolo-
gy development program is the subject of a series of N A S A
Facts pamphlets: Laminar Flow Control Technology,
NF-86, 8 pp.; Propulsion, NF-93, 12pp.; Aerodynamics,NF-94, 8 pp.; Guidance and Control, NF-95, 8pp.; and
Materials and Structures , N F-117 , 8 pp. $1.75 each.
Viking Site Selection an d Certification, SP-429, reviews th e
landing site selection an d certification process tor the
Viking mission to Mars. I t evaluates th e ut i l i ty an d
limitations of the orbital television an d infrared data an d
ground-based radar observations of candidate an d actual
landing sites. Paperbound, 40 pp. $5.50.
Wind Tunnels of NASA, SP-440, is a description of the
contribution of these important tools of aeronautical
research, whi c h are among th e least understood facilities.Bot h factual and readable, this book goes a long way to
bridging the gap between engineers an d laity. Hardcover,
154pp. $13.25.
MaterialsProcessing inSpace:Early Experiments, SP-443,reviews early U . S . efforts to s tudy th e behavior— under
conditions of weightlessness—of materials un derg oing
alteration (melting an d resol idi f ication, combining two or
more materials, g row ing crystals from aqueous solutions) in
order to produce new or more useful products. It includes
experiments that took place on the orbiting Skylab an d
during the Apollo program, an d experiments from droptowers. Paperbound, 123 pp. $11.00.
Stages to Saturn: A Technological History of the Apollo/
Saturn Lau nch Vehicles, SP-4206, is a history of the launch
vehicles that made th e Moon landing possible. The
narrative is largely predicated on the questions that may be
asked by future generations: How were th e Saturns made?
How did they work? The bulk of the book deals with th e
technological program. Paperbound, 535 pp. $10.50.
The above publications are available from th e Superinten-
dent of Documents, U.S. Government Printing Office,
Was hing t on, DC 20402.
I I
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Where to Write for Services
NASA publications should be ordered from th e Superintendentof Documents, Government P rint ing Office, Washin gton . D C20402. Publication lists, film lists, an d i n f or mat i on about otherservices are available from th e E d u c a t i o n a l Office at the NAS Acenter serving your s ta te . See the list below. There ar e specialresource centers fo r educators at the Ke nne d y Space Center,Lewis Research Center, an d Alabama Space an d Rocket Center.Huntsville, AL.
NASA Ames Research CenterMoffet Field, California 94035Alaska, Arizona, California, Hawaii, Idaho, Montana, Nevada,Oregon, Utah, Washington, Wyoming
NASA Goddard Space Flight CenterGreenbelt, M a r y l a n d 20771
Connecticut, Delaware, District of Columbia, Maine, Mary-land, Massachusetts, New Hampshire, New Jersey, New York,Pennsylvania, Rhode Island, Vermont
N A S A Lyndon B. Johnson Space CenterHous ton, Texas 77058
Colorado, Kansas, Nebraska, New Mexico, N. Dakota. Okla-homa, S. Dakota, Texas
N A S A John F. Kennedy Space CenterKen n edy Space Center, Florida 32899
Florida, Georgia, Puerto Rico, Virgin Islands
NASA Langley Research Center
Hampton , Virginia 23665K entucky, N. Carolina, S. Carolina, Virginia, West Virginia
NASA Lewis Research Center
21000 Br ook par k Road, Cleveland, Ohio 44135Illinois, Indiana, Michigan, Minnesota, Ohio, Wisconsin
NASA George C. Marshall Space Flight Center
M ar shal l Space Flight Center, Alabama 35812Al abama, Arkansas, Iowa, Louisiana, Mississippi, Missouri.
Tennessee
Th e Administrator of the National Aeronautics an d Space Adminis-tration ha s determined that the publication of this periodical isnecessary in the transaction of the public business required by law of
this Agency. Use of funds for printing this periodical ha s beenapproved by the Director of the Office of Management an d Budgetthrough December 31. 1981.
N A S A REPORT TO EDUCA TORS is published four times per yearfor th e community of educators. Recommendations are solicited fromreaders, an d should be addressed to the Education Services Branch,
Academic Affairs Division (LCG-9), National Aeronautics an d SpaceAdministration, Washington, D C 20546. Photocopying for school useis approved.
Muriel M. Thome. Editor
NASA Report to Educators
Vol. 9, No. 3 Fall 1981
Aeronautics and
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