25thanniversary Book

8/6/2019 25thanniversary Book

1/93


2/93

F--7I

MARSHALLSPACE FLIGHTCENTER

ANNBVERSARY REPORT

Nat~onal eronautics andSpace AdministrationMarshall Space Flight CenterFor sale by theSuperintendent of DocumentsU S . Government Printing Q@ceWashington, D.C. 20402


3/93

PREFACEhe Marshall Space Flight Centermarks its 25th anniversary with arecord of notable achievements:> Launch vehicle for the freeTorld's first manned spacecraft

>World's largest launch vehicles> Launch vehicles that sent man to the moon>World's only manned lunar surface vehicle> Free world's first space station> Nation's largest orbital observatories> First materials processing experiments n

space> Propulsion systems for world's first Space

Shuttle> First commercial product made in space.These accomplishments are the essence ofthe Marshall Center's history. Behind thescenes of our space launches and missions,however, lies a story of challenges faced andproblems solved. The highlights of that storyare presented in this illustrated report of ourfirst 25 years.

This book is organized not as a straighchronology but as three parallel reviews ofthe Center's major assignments: propulsiosystems and launch vehicles, space sciencresearch and technology, and manned spasystems. Our general goals have been toreach space, to know and understand thespace environment, and to inhabit and utilispace for the benefit of mankind. The text each chapter reports on the past achieve-ments, present activities, and future plans the Center as an entity; the photographsshow people at work, making history.

This three-part treatment of the Center'history is a convenience that enables us totrace the development of Marshall's majorroles with thematic continuity. In reality, ofcourse, there is considerable nterdepend-ence and inter-relationship hroughout theCenter. For example, the Apollo TelescopeMount and Skylab, discussed here in differchapters, were not two separate programsrather, the telescope was an integral part oSkylab. Within our matrix organization, allprojects benefit from the shared technical amanagerial capabilities of the Center.

This report also includes a chronology omajor events, presented as a fold-out chartfor ready reference. At a glance, the readecan see concurrent events in each of theMarshall Center's major endeavors-spacvehicles, space science, manned systemsand place them in the context of develop-ments within the Center and the communit

We are aware that the story of MarshalSpace Flight Center can be told in manyvoices, with different themes. Each employhas a unique perspective on the accomplisments of the past 25 years. This reportspeaks of the Center's achievements andchallenges in general, none of which wouldhave been possible without the specificaccomplishments of dedicated individuals.On this anniversary, we celebrate their successes and encourage all to learn from Mashall's history as they remember it. Weconsult the past to guide our progress intothe future.


4/93

TABLE OF CONTENTS

Preface iCommitment to Excellence VA Unique National Resource 1Thrust into Space: Propulsion Systems and Launch Vehicles 5Saturn 6Space Shuttle 20Advanced Transportation Systems 30A Glimpse of the Future 32Research on the New Frontier: Space Science 35Small Scientific Payloads 36Space Observatories 38Spacelab Investigations and Other Flight Experiments 46Materials Processing in Space 50Research and Technology 52A Glimpse of the Future 56A Permanent Presence: Manned Space Systems 59Lunar Roving Vehicle 60Skylab 61Apollo-Soyuz Test Project 68Spacelab 69Space Station 74Foundation for the Future: The Marshall Center People 81Chronology: 25 Years at Marshall Space Flight Center 86


5/93


6/93

COMMITMENTTOEXCELLENCE

n this 25th anniversary of the found ing of Marshall Space Flight Center, wewhose caree rs are linked to the space program feel a nostalgia that is bothcomm unal and individual; the history of NASA and our personal lives areso intertwined as to be virtually inseparable. We have changed andmatured, and so has the Center. We have grown professionally n responseto the challenges of space, and we have also become a family united byshared goals and aspirations. While we reflect on the past, we are eager toroceed into the exciting future.The G eorge C. Marshall Space Flight Center, established by Presidential Executive Orderto support a vigorous na tional program for the exploration of space, was officially designatedon July 1, 1960. During its first qua rter century, the M arsha ll Center has been recognized asone of the most capable, m ost versatile science and engineering institutions in the world.Marshall has a well-earned reputation as a developer and manager of large, complex systemsas diverse as launch vehigles, satellite observatories, and manned work places in space. Mar-shall is NASA's lead ing center for propulsion systems and launch vehicles, yet we have broad-ened our base to include many othe r quite different projects. By virtue of its multidisc iplinarytalents and resources, the Center has been, and continues to be, a m ajor force in the nation'sspace program.The history of Marsha ll Space Flight Center is a chronicle of hard work and dependablehardware. Our products -th e giant Saturn launch vehicles, Skylab, the Space Shuttle propu l-sion systems, Spacelab, Space Telescope, the many scientific spacecraft and payloads- aretremendous achievements. Our people are true pioneers, visionary leaders who extend thelimits of technology and bold ly advance into the new frontier of space.The m otivating force of Marshall Space Flight Center is a comm itment to excellence, mani-fested in the work of its people. One success after another - Mercury-Redstone launches,32 Saturn launches including 9 lunar missions, 3 Skylab missions, 3 High Energy AstronomyObservatories, some 20 Space Shuttle launches, 3 Spacelab m issions, a remarkable newSpace Telescope to be launched in 1986, and a host of other ach ievements - estify to thehighest standards of performance in our day-to-day business. The Marshall Center is a disci-plined organization dedicated to the common goa l of a successful space p rogram for thebenefit of mankind.Because our people adhere tenaciously to the standard of excellence, despite often severetime and budgetary pressures, the history of the past 25 years is a sterling record of success.Now we are poised at the threshold of ano ther great endeavor that will challenge us far intothe future -the establishment of a perm anent presence in space in an inhabited Space Sta-tion. What we do today and what we are capable of achieving tomorrow depend on our contin-ued, unstinting commitment to exce llence in thought and deed , in theory and practice.We have ce rtain traditions at Marshall: p rofessionalism and quality in all disciplines, e ffec-tive management, teamwork, pioneering scientific research, and advancing technology. Thisheritage continues in our work today, and it must remain vital in our future efforts. Our historyis not a closed book; it inspires and guides us.As I ook back to the origins of Marshall Space Flight Center, our history appears in theblinding light of rockets and launch vehicles. Looking ahead, Isee a future equally bright withchallenges that will tax our ingenu ity and demand our best efforts. As always, we will succeedif n our daily work we honor our com mitment to the standard of excellence.That is the Marshall tradition; may it remain so.

W. R. Lucas, DirectorGeorge C. Marshall Space Flight Cen terJuly 1985


7/93

German rocket experts in Fort Bliss before m oving to Huntsville

Rocket Center Archives photo

-

In the blockhouse at C ape Cana veral awaiting launch ofPioneer 4 (1 959)

IThe United States' first satellite , Explorer 1IPioneer 4 probe, first U S . Isatellite to orbit the sun,launched in 1959

1= " ,


8/93

t Huntsville we have one of theImost capable groups of spacetechnicians in the country," aofficial told con-gress in 1959. "1 think that it

PJebame Space end Rocket Center Amhives photo

-is a unique group ...a national resource oftremendous importance."Years before either the NationalAeronautics and Space Administration(NASA) or Marshall Space Flight Center(MSFC) was established, a group of scientistsand engineers known as the von Braun rocketteam became prominent in America's fledglingspace program. Dr. Wernher von Braun and

118German rocketry experts and their familiescame to the United States in the mid-1940's.Initially employed by the Government at FortBliss, Texas, the group moved to Huntsville in1950. Here the Army's Redstone Arsenaloffered an excellent site for basic rocketresearch and guided missile development.- . . .- - - . . . .

became head of the ABMA DevelopmentOperations Division.During this period of rapid change, themomentum toward space flight increased. Ashead of various missile development activitiesin Huntsville, Dr. von Braun played an influen-tial role in the formulation of national spacepolicy. Among the many issues debated byadvisory committees to the Government wasthe matter of military and civilian uses ofspace. Although affiliated with a military

uurlng tne 19508S, nis team was expandedby nation-wide recruitment of scientists and "1 consider the explorationengineers, and it became the core of theArmy's Guided Missile Development Group. of space and the extensionThe n r o u ~nitiated research and develo~ment of human activities beyondof the 75,'ooo pound thrust Redstone guided the confines of our planetmissile, first launched in 1953, and started the the supreme chailengelarger Jupiter missile program in 1955.Thenext year, the Army Ballistic Missile Agency of the age in which we live=(ABMA), which incorporated this resident Dr. Wernher von Braun, 1957technical cadre in key positions, was estab-lished at Redstone Arsenal. Dr. von BraunExplorer 1 ready for launchatop Jupiter C rocket (1958)

Explorer project leaders :Dr. Rees, Major G en. Medaris,Dr. von Braun,Dr. Stuhlinger and (b ehin d)Mr. Mrazek andDr. Haeussermann

Alebeme Space and Rocket CenterAmhimspholo


9/93

A UNIQUENATlONALRESOURCE

iUS, &my, Reastone h en e l photoABMA laboratorydirectors

Fireworks indowntownHuntsville t ocelebrate Explorer Ilaunch

agency, Dr. von Braun was a strong proponentof the scientific exploration of space and thedevelopment of la rge launch vehicles for thispurpose.Meanwhile, the von B raun team was busysolving the theoretical and p ractical problemsof rocketry. Already members of the groupwere studying the feas ibility of larger boosterswith much greater thrust and payload-carryingcapability for orbital and deep space m issions.Through dozens of Redstone and Jupiterstatic firings and tes t flights, they were resolv-ing some of the d ifficulties in rocket design,propulsion, and performance.Due to their foresight in planning and prep-aration, the ABMA group was ready for theUnited States' first launch of a satellite. Hav-

ing anticipated the space age, the rocket teresponded quickly when launch was au thoized. In January of 1958, the ABMA loftedAmerica's first satellite, Explorer I, into orbiaboard the Army's Jupiter C ocket, just th rmonths after authorization. During the nexttwo years, the ABMA launched six other scentific satellites, including a Pioneer thatorbited the sun.The initial success with the Jupiter rockspurred the von Braun team and the ABMAtoward an even more ambitious big boosteprogram, originally named the Juno, foradvanced space missions. In 1959,a sepaDefense Department organization, theAdvanced Research Projects Agency (ARPauthorized ABMA to begin a research anddevelopment program for a vehicle having 1.5million pound thrust capability. This tre-mendous advance was to be achieved byclustering eight available rocket engines inone stage. The major goal of the program a demonstration static firing by the end of1959.The Juno program was renamed Sain 1959, and soon thereafter the projectreceived the highest national priority ratingMembers of the rocket group in Huntsvillewere enthusiastic about the new project; thhad been nurturing the concept for years, they were eager to proceed.In the meantime, NASA was founded in1 I958 by an Act of Congress to support a vous civilian space program. The new spac1 agency included elements from various exing laboratories and installations, but it d id

~ u n t s v , l l e - ~ a d ! s s o n ~ ~ ~ n l y ~ u ~ ~ c ~ b ~ a r y ~ h o t oave a strong capability for developing lauvehicles and propu lsion systems. After extsive negotiations, the ABMA's DevelopmeOperations Division headed by Dr. von B rand the Saturn project were transferred frothe Department of De fense to NASA in 19

President Eisenhower and Mrs. George CMarshall at dedication ceremony for NASMarshall Space Flight Center


10/93

"After thousands of yearsof clinging to our planet,man is finally about toburst the bonds of terres-trial gravity and embark onthe greatest voyage of hisentire existence. . . heexploration of the spacearound him."Dr. Wernher von Braun, 1958This transfer strengthened the agency consid-erably and also guaranteed the rocket team'sactive participation n the scientific explorationof space.On July 1, 1960, the George C. MarshallSpace Flight Center officially came into beingas 4,670 civil servants previously associatedwith the Army became NASA personnel, and1,840 acres of Arsenal property and facilitiesworth $100 million were transferred to thespace agency. For several months, theMarshall group continued to work at the samedesks in the same Army buildings. The neworganization resembled the old, and the conti-nuity of personnel and activity was hardlyaffected by the transfer. In addition to theSaturn project, Marshall assumed responsibil-ity for the Juno II rocket, the 1.5 million poundthrust F-1 single engine, development of theAgena B stage of the Atlas and Thor boosters,development of the Centaur launch vehicle,and development of the Mercury-Redstonevehicle for NASA's first manned program,Project Mercury.Dedicating the new NASA center in Sep-tember, President Dwight Eisenhowerremarked that General George C. Marshall,the distinguished soldier and statesman, wasa builder of peace. The decision to name thecenter in his honor was also a fitting tribute toboth the agency and the team of rocketrypioneers whose origins were in militaryresearch but who aimed for the peaceful sci-entific exploration of space.Thus, when Marshall Space Flight Centeropened for business in July of 1960 it wasalready a thriving enterprise. Its work forceincluded many people who had alreadyworked together for a decade or longer. Itsfounding director was Dr. Wernher von Braun,an advocate of space research and develop-

ment activities for more than 20 years. Majorprograms were already established and inprogress, and its organizational philosophywas in place. The new center had excellentlaboratories for rocket propulsion systemdesign, development, manufacturing, and test-ing. Its technical capabilities were unsur-passed, and its morale and team spirit werevigorous.The Center was born in an atmosphere ofurgency, at a time when the nation's goals inspace were not yet clearly focused. The spaceenvironment was unfamiliar territory and therewere many uncertainties about appropriatetechnology and suitable missions. To thosewho had been working with rockets, the nextstep seemed obvious: bigger, more powerfulboosters to place communications andweather satellites into orbit, to send planetaryprobes into deep space, to carry people andtheir living quarters or workshops into space,and to begin studying and using space for thebenefit of all mankind.While public consensus was forming, thecadre of rocket experts in Huntsville pro-ceeded apace with the task of developingawesome new launch vehicles- he massiveSaturn family. Despite the unparalleled experi-ence and expertise that made this group aninvaluable national resource, the Saturn proj-ect challenged all their technical and manage-rial abilities. From this beginning arose thetraditions that sti ll characterize MarshallSpace Flight Center today: engineering excel-lence and the disciplined concentration ofenergy essential for success.

Breaking new' ground for thenation's spaceprogram


11/93


12/93

la z e of light andding thunder, a! vehicle rises fromic h pad. For most3rs, a lift-off marksling , a take-off, theIn adventure. Forgineers, however,.inch is a climact ic

,.,, .t, the culmina tionof years of hard work. While others watchexpectantly, those who have designed or builta vehicle wait tensely for the m oment of re liefand jubilation, the spectacu lar moment ofproof that their work has been done well.Marshall Space Flight Center developedthe engines and vehicles that boosted ournation into space. Transportation systemshave been a crucial part of the Center's busi-ness, from the early Redstone rockets to thesophisticated Saturn launch vehicles and on tothe Space Shuttle and the advanced craft thatwill serve us in the Space Sta tion era. At everystage, the development of propu lsion systemsand vehicles for space flight has posed techn i-cal and managerial challenges. There was noprecedent for the pioneering work of establish -ing safe, re liable transportation service intospace. The h istory of this Marshall Centerachievement is one of problems solved, chal-lenges met, and successes recorded .

"Ithink we've got a fantasticand remarkable capabilityhere. We're really not too far... rom going to the stars."John YoungCommander, STS-1,1981


13/93

THRUST Marshall Space Flight Center came into beingINTO SPACE with a charter to develop a launch vehicle ofunprecedented size and power. As the pace ofthe space program quickened in the late19503, a bold leap was urgently needed toestablish American technological pre-emin-ence. That advance, of almost inconceivableproportions, was the Saturn series- heSaturn I,Saturn IB,and SaturnV launchvehicles.

The new vehicles would be gigantic com-pared to their predecessors, which were them-selves barely off the drawing boards and teststands. They would have remarkable thrust andlift capability. Whereas the 70-foot Redstonegenerated about 75,000 pounds of thrust forsuborbital flight, the Saturn Iwas first envi-sioned as a 165-foot, 1.5 million pound thrust

giant capable of attaining Earth orbit. Thoseinitial specifications were soon revised upwand the largest member of the family, the toering 363-foot Saturn V, ultimately became multi-stage, multi-engine vehicle standing tathan the Statue of Liberty. With a first-stagethrust of 7.5 million pounds and another 1.2million pounds in combined upper-stage thrthe Saturn V was capable of sending man tthe moon.

Although the origins of the Saturn concelay in ongoing rocket research within the ArBallistic Missile Agency and other military pgrams, a strong impetus to the Saturn progwas President John F Kennedy's 1961announcement of the nation's foremost goaspace: a manned lunar landing within the dade. As early as 1959, NASA was alreadylooking toward this goal in its long-range plning, but not within the same time frame; alunar landing in the early 1970's was contemplated. Now, before a single American hadbeen thrust into orbit, NASA and the nationwere committed to an extremely ambitious

"I believe that this nationshould commit itself toachieving the goal, beforethis decade is out, of landing a man on the Moonand returning him safelyto Earth."President John F. KennedyMay 25,1961

Saturn engines and stages

First Saturn V launch(Apollo 4),November 9,1967


14/93

endeavor. The Saturn program, the MarshallCenter's first major responsibility, crystallizedabout this goal. The new family of extraordi-narily large launch vehicles was required forthe Apollo lunar missions.

Marshall Space Flight Center was a foun-tainhead of activity during the months of earlySaturn-Apollo planning. NASA had decided touse the Army's Redstone ballistic missile andthe larger Air Force Atlas missile as boostersfor Project Mercury, which would lay the foun-dations of manned space flight in preparationfor the Apollo missions to the moon. ToMarshall fell the responsibility of modifying theRedstone vehicle for the first manned suborbi-tal missions.

After several unmanned test launches in1960and a flight by the chimpanzee "Ham" inearly 1961, the Mercury-Redstone systemswere judged flight-worthy for a manned mis-sion. In May of 1961,Marshall's Redstone vehi-cle boosted America's first astronaut, Alan B.Shepard, on a successful but brief suborbitalflight. A modified Redstone was used on asubsequent Project Mercury flight, andMarshall's track record of successful launchesbegan to grow convincingly.The original Marshall organization includeda Launch Operations Directorate responsiblefor launching test flights and the Mercury-Redstone flights. In 1962, this Marshall launchteam moved to Cape Canaveral and its leader,Dr. Kurt Debus, became the first Director of theLaunch Operations Center there, laterrenamed as Kennedy Space Center. Anexceptionally close working relationshipbetween the two Centers has continued sincethat time.

For the next several years, other elementsof NASA methodically perfected spacecraftsystems and orbital rendezvous echniquesthrough the Mercury and Gemini missions.Meanwhile, Marshall surged ahead to preparethe launch vehicle for the Apollo lunarmissions.

In the interests of time and economy, thedevelopers of the Saturn vehicles relied heav-ily on contemporary rocket design and propul-sion technology. Nevertheless, the Saturnrepresented a dramatic departure from earlysingle-engine, single-stage rockets. To achievethe thrust necessary for manned lunar mis-sions, it was essential to develop a multistagevehicle with clusters of engines and to usehigher performance propellants and propulsionsystems. Advanced missions and heavy pay-loads meant more engines, bigger launch vehi-cles, and higher-energy uels.

Saturn I test firing at MarshallScaling up to the massive Saturn dimen-sions was a major challenge. Even though pro-totypes of some components existed, theywere not as large as the new vehicle required.In addition to basic advances in rocket technol-ogy, related developments in materials, analyti-cal techniques, tooling, fabrication techniques,and test facilities were necessary. In fact, rapidadvances in the state of the art were neces-sary in almost every technical area.

How did the Marshall Center turn theSaturn concept into reality? What technicalchallenges did Marshall people meet, andwhat did they contribute to the state of the artin critical engineering disciplines? These ques-tions have been explored in detail in other doc-uments; a summary here will distill theessence of the Marshall Center's achievement.

To manage the tasks of developing, pro-ducing, and integrating the large multistagevehicles, Marshall's initial organizationincluded a Saturn Systems Office with respon-sibility for managing all aspects of the Saturnprogram. As the program evolved andmatured, the Systems Office was subdividedinto three project offices for Saturn l/lB,Saturn V, and engines. The project offices inturn were subdivided into offices for eachvehicle stage or engine. By 1963,a largeamount of Saturn wbrk was being performedunder contracts, and the Saturn managementoffices were organized under the aegis of anew Industrial Operations Directorate.


15/93

Technical expertise for Saturn was pro-vided by the Center's nine engineering labora-tories: Aero-Astrodynam ics, Astrionics,Computation, M anufacturing, Propulsion andVehicles, Quality and Reliability Assurance ,Test, Launch Vehicle Operations, andResearch Projects. These spec ialized disci-pline laboratories, which had their origins inthe ABMA organ ization, constituted most ofthe Research and Deve lopment OperationsDirectorate. Their importance to the Saturnprogram was incalculable; the laboratoriescontinually pushed the limits of the state ofthe art in all fields to develop the designs,materials, and technology that made Saturnpossible. A major factor in the success of theprogram was the creative technical excellenceof the Marshall Center laboratories.The Saturn family of boosters includedthree vehicles: the Saturn Iand I6 for develop-ment purposes and early Apollo flights, andthe Saturn V for the actual lunar missions.Even before the Saturn project was o fficiallyNASA's responsibility, the von Braun groupand other space p rogram officials vigorouslydebated the question of configuration. It was a

would need several stages and clus ters ofengines, but dozens of arrangements werepossible. Dec iding upon the basic architectureof each Saturn vehicle was a dilemmaresolved by careful deliberation. How manystages, of what height and diameter, howmany engines per stage, what type andarrangement of engines would stack up tomake the best booster? The Saturns were

"Few of man's technologi-cal endeavors compare inscope of significance tothe development of theSaturn family of launchvehicles. . .Saturn was anengineering masterpiece."Dr.W.R. Lucas

foregone conclusion that the g iant boosters

ApoComModServMod

\ LunlnstrUnit

Seco(S-11)5 J-2

Test firing of Saturn IC stage at MSFC


16/93

hybrid vehicles combining new ly designedclustered-engine stages and new eng inetechnology.Marshall Space Flight Center personnelwere deeply involved in the vehicle conceptwork. The decision was made in early plann ingstudies to use a first-stage cluster of eightmodified Jupiter engines burn ing a kerosenedistillate fuel called RP-1 with liquid oxygen.The choice of upper-stage engines and config-urations, however, was less clear. After initialconsideration of various conventional missilestages, NASA op ted in 1959 to use new liqu idhydrogen engines in the second and thirdstages. Saturn configurations stayed in flux asvarious concepts for stages and engines wereevaluated and parallel development effortsproceeded. By 1962, the broad configurationissue was settled, though many interfacingdetails remained to be worked out.Marshall Space Flight Center carried outdevelopment, testing, and production of theSaturn I irst stage in-house until Chrysler Cor-poration became the prim e contractor in late1961. The in-house effort established the basicdesign for clustered engines and clusteredpropellant tanks, the pumping scheme for asteady and balanced propellant flow fromtanks to engines, the struc tural skeleton andskin for the unusually large stage, and theguidance and control mechan isms for steeringthe vehicle during powered flight.The flawless first launch in October of 1961validated the Saturn vehicle concept nurturedat Marsha ll. In ten successful Saturn Ilaunches between October 1961 and Ju ly1965, engine performance and vehicle reliabil-ity were convincingly demonstrated. E ight ofthe ten Saturn I irst stage boosters were builtat Marshall, the others by Chrysler CorporationSpace Division. Five second stages (two fortesting and three for flight, a ll unpowered"dummies") were built at Marshall beforeDouglas Aircraft Company began to supplythem under contract. In addition, five Saturn Vfirst stages (three for ground tes ts and two forflight) were fabricated in-house at Marshall.After this initial production, all stages of thethree Saturn vehicles were produced by con-tractors (Douglas, North American, IBM,Rocketdyne, Pratt and Whitney, and Boeing)under Marshall Center management.Launch vehicle configu ration was contin-gent upon powerful rocket engines, the prereq-uisite for space flight. Much of the MarshallCenter's early effort was directed towardadvahced engine technology and higher-energy propellants. Fuel-efficiency assess-ments pointed to liquefied gases as the most

Working overtime to keep Saturn on schedule

--J-2 engine static firing

Saturn hunch w h k l e engines


17/93

THRUST promising new propellants for advanced m is-- -INTOSPACE sions, and to liquid hydrogen in particular,because conventional propellants could notsupply the necessary thrust and high perform-ance for heavy-payload lunar missions requir-ing escape velocities.When liquid hydrogen was selected forSaturn's upper stages, its use as an enginefuel was experimental. In add ition to proving itsperformance, engineers faced a host of log isti-cal problems associated with storing, pum ping,and transporting the fuel, which i s highlyexplosive and must be m aintained atextremely low (cryogenic) temperatures, morethan 400F below zero. Advances in insu lationmaterials and in the design of large cryogenicstorage tanks and pumping systems wererequired by the se lection of liquid hydrogen asa propellant for Saturn upper stages.As the Saturn program evolved, theMarshall Center worked closely with contrac-tors to improve or develop engines for eachvehicle stage. Two first-stage engines (the H-1and F-1) and two h igh-energy upper stageengines (the RL-10 and J-2) were usheredEarly Saturn I launch, w ith through research and developm ent, testing,"dumm y''sec0nd stage and production, and launch. The most visible (andpayload

audible) evidence of Marshall's role was thstatic firing test ac tivity in Huntsville. Localzens had frequent thunderous reminders ththe space program was in progress ust nedoor.The first-stage engines used a conven-tional kerosene-liquid oxygen propellant anexisting engine concepts. The main engineing challenges were to cluster and en largeengines for much higher thrust, which introduced problems that required innovative sotions. For example, some of the engines wegimballed for directional control of the vehicpowered by the combined thrust of eightengines. New ducting and ven ting techniquwere used to deliver propellants to the mulengines. Manufacturing problems resulted new materials and manufacturing processeTurbopumps and thrust chambers wereimproved for un iform propellant flow and cobustion under very severe temperatures anpressures. Special instrumentationwas deoped to evaluate engine performance undedynamic conditions. While the first-stageengines had a heritage of proven technologscaling up resulted in many advances.A p rototype uprated H-1 engine developby Rocketdyne was first tested in 1958; aneight-engine cluster was tes ted and flight rat M arshall in 1960, during the Center's firsyear. Models of this workhorse ranged in thfrom 165,000 to 205,000 pounds per enginfor a total thrust of more than a m illion pounin a Saturn Ior 1B first-stage cluster. The F-1engine, developed to meet the greater thrustdemands for Saturn V launches, yielded anawesome7.5 million pounds of thrust in a fivengine first-stage cluster. Also developed byRocketdyne, this engine was first tested in 1then tested in a cluster at Marshall in 1963, afirst flown in 1967. Both first-stage enginesproved highly reliable.While suitable engines for Saturn firststages were developed by enlarging and mfying existing designs, there were no ava ilaliquid hydrogen propulsion systems. Withoproven technology, NASA undertook the deopment of entirely new engines for Saturnupper stages. Management responsibility this pioneering engine work was assigned Marshall Space Flight Center at its foundinThe new engines represented major technlogical breakthroughs n propulsion systemdesign and performance.The initial upper stage engines used inSaturn Ivehicles were derived from the RLhydrogenloxygen engine under consideratin the late 1950's by the Air Force. When binto an upper stage, this engine would ena


18/93

Atlas missiles to launch heavier payloads,such as communications satellites. NASAinherited responsibility or the RL-10engineunder development by Pratt & Whitney, and by1959 it was destined for use in the Saturn IBupper stage. Engine testing occurred atMarshall Space Flight Center and other sites,and by 1961 the high-performanceRL-10 liquidhydrogen engine was flight rated. The selectedconfiguration for the Saturn I second stagewas a cluster of six engines, each having15,000 pounds of thrust; its first flight occurredin 1964.Concurrently with RL-10engine develop-ment, NASA was planning ahead to liquidhydrogen engines of even greater thrust,200,000 pounds each, to be used singly or inclusters. Beginning in 1960, development ofthe J-2 engine was undertaken by Rocketdyneunder Marshall Center management. Thesehuge engines became the powerhouse forSaturn IB and Saturn V upper stages. A singleJ-2 engine was used in the Saturn IB secondstage and SaturnV third stage; five of theseengines were clustered in the Saturn V secondstage for a million pounds of thrust. Followingsuccessful tests in 1962, the engine enteredproduction in 1963 and was first flown in 1965.As manager of the engine developmentprojects, the Marshall Center was immersed inall the design issues and technical problemsfacing its contractors. Together, the govern-ment-industry team faced the challenges ofscaling up existing concepts and simultane-ously working out new technology. The Centerrelied on its in-house laboratory expertise inpropulsion systems, metallurgical and mate-rials research, fluid dynamics, structures,dynamics, and other disciplines for the neces-sary engineering advances. Notable achieve-ments included the application of lightweight,durable materials capable of withstandingextreme temperatures and stress, new heat

Altogether the Saturn Vengines produced asmuch power as 85 HooverDams.

F-1 engine static firing test at Marsha ll

J-2 engine assembly line atRocketdyne facility inCanoga Park, C alifornia


19/93

THRUST treatment for alloys, innovations in turbomachi-INTO SPACE nery design for improved efficiency, and m yr-iad other improvements in component designsand fabrication techniques to m eet the unique boperational demands of the Saturn vehicles.-Throughout the 19601s, he Center also m ain-tained engine testing programs in Hun tsville /

concurrent with testing at contracto r sites.At its founding, Marsha ll had inherited the 1Army's Jupiter and Redstone test stands, but amuch larger facilities were needed for Sa turn V

Transport of Saturn S-16stage from dock to MSFCtest stand

testing and for m anufacture of the giantstages. Bes ides expanding its own facilities,Marshall acquired three additional installationselsewhere in the early 1960's. In a relatedexpansion, Marsha ll acquired or built bargesand docks to develop a suitable system fortransporting the huge Saturn elements to thelaunch site. All of these fac ilities operatedunder the jurisdiction of Marshall Space F lightCenter. The complexity of this construction andlogistics effort was a m ajor challenge thatrequired a substan tial investment.From 1960 to 1964, existing test stands atMarshall were remodeled and a sizable newtest area was developed. The new towerserected for propulsion and structural dynamic

The Center's barge dock onthe Tennessee River

Marshall's Mississippi TestFacility, where Saturnstages began journey toHuntsville

Saturn I6 static test at the Marshall Center


20/93

Temporary quarters in theHuntsville Industrial Centeras MSFC grew

tests were among the tallest buildings in the A government-owned computer facility instate. They also made up a comprehensive Slidell, Louisiana was enlisted to support thetest complex for static firings of extremely pow- Michoud ~ l a n tnd Mississippi test site. A com-erful engines, storage and pumping of cry-ogenic fuels, and structural evaluation ofinordinately large objects. The Marshall testareas were unique within the nation and thefree world, and they remain so today becausethey were constructed with foresight to meetfuture as well as original needs. The Centeralso expanded its local production facilities forin-house fabrication of the early Saturn stages,

The Michoud Assembly Facility in NewOrleans, Louisiana, a component facility of theMarshall Space Flight Center, became themanufacturing and assembly site for theSaturn IB and SaturnV first stages. Jointlyoccupied by the two prime contractors, Chrys-ler and Boeing, the plant had over 3 millionsquare feet of production and office space,with 43 acres under one roof. The facility,located on the Gulf intracoastal waterway, waswell situated for barge transport of the stagesto test and launch sites.

Nearby in Bay St. Louis, Mississippi, theMarshall Center constructed a massive newengine test complex. Three huge test standssurrounded by laboratories, fuel storage tanks,and support facilities rose from the wilderness.Saturn stages were test fired and qualifiedhere by a contractor workforce under Marshallmanagement. Originally a part of the Marshallcenter, the ~i ss is si pp i~ es tacility laterbecame an independent NASA installation.

m

ponent installation of the ~ grshal l enter, theSlidell Computer Complex provided criticaldata processing services for Saturn test,checkout, simulation, and engineeringactivities.

In parallel with the development of enginesand stages, Marshall Space Flight Center wasengaged in developing the Saturn vehicle'sinstrument unit for guidance, navigation, andcontrol. This "brain" controlled all the ignitionsequences, stage separations, guidance andcontrol, and telemetry functions to keep thevehicle operating properly and on course.Begun as an in-house project, which evolvedthrough several versions, the sophisticated uniteventually was contracted to IBM for finaldesign and manufacture. Its continuing refine-ment was marked by notable advances incomputer memory, logic, and instrumentdesign using new alloys and miniaturizationtechniques that found a ready commercialmarket in a variety of consumer products.)Building Confidence

The key word for the Saturn developmenteffort was performance. Given a highly visibleand costly space program, strong pressure tomeet goals on schedule, and the importanceof crew safety, everything possible was doneto ensure the reliable performance of everySaturn element. As program manager,Marshall Space Flight Center led the way inestablishing both technical and managerialpractices that built confidence in the Saturnvehicles. The result was 32 consecutive suc-cessful Saturn launches, the complete pro-gram including 9 lunar missions.A fleet ofextraordinarily reliable vehicles boosted thespace program to success.

The confidence factor derived from con-servative design, extensive testing, and strin-gent quality control, all based on meticulousattention to detail. Simplicity, building blocks,and tests were the key tenets of thisphilosophy.

At virtually every point, Marshall engineersfavored design simplicity. Undue complexityintroduced greater risks that could jeopardizethe schedule or the entire program. As theyscaled up existing components and systems,engineers kept a keen eye on ways to stream-line the designs. While they developed designsfor new items, they also looked for ways to

Construction of towering new test stands atMarshall, 1960- 1964


21/93

THRUST make things work without burdensome com-lNTO SPACE plexities. The novel J-2 engine design admira-bly illustrated this principle; many componentsin this propulsion system served more thanone purpose.

Marshall engineers and managers favoreda building block approach to the ambitiousSaturn program. To ensure steady progresstoward a launch vehicle that had no ~recedent.they organized the development effdrt inphases to prove the technology for each phasein a relentless step-by-step fashion. Eachmajor element- an engine or an entire stage,for example-was a building block that wasadded to the configuration in due course. Sys-tems were gradually built up as componentswere tested and proved; likewise, the vehiclegradually evolved as one element afteranother was added and exercised.

The Saturn I aunch series illustrated thisbuilding block approach to development bysuccessive additions: initially only the firststage was live, with a dummy upper stage;after more checkout flights, a live upper stagewas added; then a functional payload wasadded. The Saturn I tself was a building block

for the IB vehicle, which in turn was a buildblock for the Saturn V. This methodical deopment scheme proved so reliable that theSaturn I was rated operational three flightsahead of schedule, and the first Saturn V fwas an "all-up" mission with all stages liveThe decision for an all-up first launch was bold break from precedent, made after mudeliberation; n balance against the inhererisk of initial failures was the confidence faso painstakingly nurtured at Marshall.

Marshall also was firmly committed to orous testing. To avoid surprises in flight, eneers subjected Saturn components to evconceivable stress and strain anticipated ding a mission. Extremes of temperatures,pressure, vacuum, and vibration even greathan those predicted for launch and spaceflight were devised in laboratories and teststands. New facilities were built and existintest facilities at both the Center and at contor locations were scaled up to accommodthe massive Saturn elements. Saturn test checkout activities spawned remarkableadvances in electronic simulators and automated test equipment. This apparatus cou

Saturn I build-up at MSFC Installation of engines Checkout of the co mplete d bo

Assembly of the InstrumentUnit, Saturn's complex"brain" for guidanc e,navigation and control


22/93

create a high-fidelity simulation of launch andflight or could take the pulse of hu ndreds ofdifferent parts to provide enginee rs withdetailed performance data. In addition to testand checkout data, hund reds of measure-ments of actual flight pe rformance were col-lected via telemetry.The emphasis on pe rformance and reliabil-ity penetrated all levels of the Saturn programfrom top-tier management to production ~ i n dworkers. The stra tegy of techn ical competence-of doing things right- was evident every-where. Dr. von Braun, for example, expresseda "dirty hands" philosophy, encouragingCenter personnel to keep themselves steepedin technical m atters. This would make thembetter engineers and better managers of con-tract work. One of the Saturn prog ram's bestinsurance policies was the distinctive compe-tence resident in Marshall's laboratories andshops.Although all Saturn launches were suc-cessful, there were occasional problems andmoments of anxiety. A particu lar cause of con-cern on the first Saturn V flights was the "Pogoeffect," vertical vibrations that occurred duringpowered flight. Lasting only a few seconds,these "bounces" increased stress on the vehi-cle. A Pogo task force did the necessarydetective work to understand the Pogo phe-nomenon and implement corrective measures.The vibrations were successfully suppressedin time for the first m anned Sa turn V flight.

)Working as a TeamMarshall Space Flight Center faced a m anage-ment challenge beyond the scope of any pre-vious techno logical endeavor. As many as20,000 contractor companies across thenation were involved in p roducing the millionsof parts that made up each Saturn launch vehi-cle. Furthermore, the engines an d stages forthe three differen t vehicles were evo lving rap-idly and in pa rallel, which com plicated plan-ning and coord ination . To stay abreast of thestatus of all p rogram activities and to fosterreliability everywhere, the Center used a num-ber of new managem ent, systems integration,and program control methods both in-houseand in the contractors ' territory.Teamwork characterized Marshall's rela-tionships with its contractors. As the S aturnprogram evolved in scope, the developmentand production requirements exceeded theCenter's capacity to do all work in-house.Therefore, the Center set about building astrong governmen t-industry-university eamwith joint participation in working groups a ndextensive Marshall involvement in contractor

activities. In this tripartite endeavor, the aca-demic community con tributed substantially tostudy and design activities, and the industrialcommunity played major roles in developmentand manufacturing. This m utually beneficialcooperation resulted in the successful Saturnprogram.The purpose of the teamwork philosophywas to ensure success by frequent and candidinteractions between the government customerand the industrial supplier. This was accom-plished by formal and informa l meetings, byperiodic progress reviews, and in m ost casesby a resident management office at the p rimecontractor sites staffed by Marshall personnel.Such close coordination and m onitoringensured that problems were recognized andresolved early, with minim al impact on costs orschedule.k

7. Marshall Space Flight Ce nterHuntsville, AlabamaVehicle Managem entBoeingSystems EngineeringGeneral E lectricGround Support EquipmentIBMInstrument U nits

2. BoeingKent, WashingtonLunar Roving Vehicle3. SACTO Test FacilityDouglas AircraftSacramento, CaliforniaS-IVB Test Operations4. McDonnell DouglasHuntington Beach, CaliforniaS-IVB

North American R ockwellSeal Bea ch, CaliforniaS-11North American RockwellCanoga Park, CaliforniaH-1, J-2, F-1 engine s

5. Manned Spacecraft CenterHous ton, TexasSpacecraft, Mission Control6. Michou d Assembly FacilityNew Orleans , Louisiana

BoeingS-ICChryslerSaturn IB

7. Mississ ippi Test FacilityBay St. Louis, Mississ ippiS-IC & S-11 Test Operations8. Kennedy Space Cente rLaunch Operations9. NASA HeadquartersWashington,D.C.

10. BendixTeterboro, New JerseyInertial Guidance Plattorm


23/93

always been a critical and untouchable con-stant at Marshall. Therefore, when a difficulttechnical problem occurred, the Center identi-fied a group of experts from the relevant labo-ratory disciplines to examine and penetrate theproblem on-site. After thorough study to under-stand the intricacies of the problem and sys-tematically evaluate alternatives, the teamcontinued its focused effort until a workable,effective, and reliable solution was achievedand implemented. The Tiger Team conceptthat originated with the Saturn program subse-quently remained a valuable means of resolv-ing technical problems with dispatch.The evolutionary nature of Saturn develop-ment activities created a need for careful con-figuration control. Marshall establishedstringent new guidelines for documenting alldesign specifications, design changes, engi-neering discrepancies, and related mattersthat could affect the integrity of any Saturn ele-ments or their interface characteristics. For areliable launch vehicle, everything had to mateexactly. There could be no surprises on thelaunch pad.To further motivate the contractors,Marshall began to offer incentive fee andaward fee contracts. These incentives encour-aged the best possible performance to meethardware deliveries on schedule. Incentives atthe individual worker's level were offered byManned Flight Awareness programs within theagency and at contractor plants to remindemployees of the importance of their work. Themessage was clear: No one could afford tomake mistakes.In-house, Marshall developed several veryeffective teamwork techniques that promotedaccountability- keeping track of who wasresponsible for what - and enabled managersto make well-informed decisions. From the out-set, Marshall had a democratic propensity forconvening committees, working groups, andpanels to resolve problems or advise policy. Animportant device for fostering such teamworkwas the Saturn Program Control Center, abriefing room outfitted with charts, projectionscreens, closed-circuit audio and television,and other aids for communication and informa-tion display. A hub of activity for several years,this was the place where managers met tomonitor progress and keep the program'scourse on target.

As the Marshall Center's first major assign-ment, and a spectacularly successful one, theSaturn program left its imprint on the institutionand its surroundings. During that time, theCenter expanded into its own new buildingsand, in 1965-1966, reached its peak work forceof 7,327 employees and budget of almost $1.7billion. The rapid physical expansion of theCenter was accomplished by an enormouseffort o plan, establish, and manage the newfacilities. Similarly, the growing work force andincreasing complexity of technical activitiesresulted in a sustaining administrative servicesand support organization.As NASA began to procure more technicalservices, a large support community of aero-space contractors and high-tech ndustry grewin Research Park and stimulated the localeconomy. During the Saturn era, the popula-tion of Huntsville increased 8-fold from 16,000in 1950 to 136,000 in 1970. The face of the citychanged as new roads, residential areas, civicfacilities, a university, and the Alabama Spaceand Rocket Center opened. That close tiesbound the institution and the community wasperhaps most evident in the spontaneous pub-lic celebrations of the first American satellitelaunch and the successful landing on themoon; Wernher von Braun, the man who hadbeen so influential in making Marshall andHuntsville the "Home of Saturn," was carriedalong the streets in triumph, like the coach of awinning team.For a decade, Marshall's human and physi-cal resources were largely devoted to Saturnwork. The institution survived its growingpains, and the practices that proved effectivebecame habitual. A changing organizationchart reflected the Center's evolution towardmore diverse and complex responsibilities.Many of the Center's lasting strengths areSaturn legacies: its multidisciplinary technicalcompetence, its flair for large-scale systemsengineering and systems management, itspartnership with industry and universities, itsperfectionism expressed in reliable products,and its dedicated work force committed toexcellence.The Saturn program did not quite end withthe last Apollo mission in 1972. Saturn vehicleswere used to launch four Skylab missions in1973 and the Apollo-Soyuz mission in 1975.These grand finales launched two new con-cepts in America's space program: a long-termpresence in space for scientific research, andinternational cooperation in manned space-flight. On those notes, the Saturn era closed.During the Saturn-Apollo era, much ofMarshall's attention and energy had been

Celebration of the lunar ladowntown Hunts ville, July

At the Marshall Cente rfamily picnic a few daysafter the lunar landing


24/93

THRUSTINTO SPACE

Elation in the launch con trol center afterApollo I1 lift-off

the firing roomlaunch

President Kennedy greetingemployees during 1962 visitto Marshall-


25/93

Earthrise

focused on one goal, the development of ppulsion systems and launch vehicles for thelunar landing program. As the Apollo prograwaned, the Center made a deliberate and pdent decision to become m ore diversified. Tkey event in Marshall's transition from a sinproject to a m ulti-project Center was the cretion of the Program Development directora1969, under the leadership of today's CenteDirector, Dr. W. R. Lucas.At the nucleus of the new directorate wefuture planners drawn from the laborato riesand now charged with responsibility for coonated long-range planning to conceive newprograms for the agency and the Center. Tgroup formed task forces to focus on prom iing new programs and conducted advancestudies, feasibility studies, preliminary desigand program definition. The Program Devement directorate rapidly became an e ffectivadvocate of Marshall Center capabilities an"think tank" for original project concepts.Through its efforts, the Center participated early Space Shuttle concept work that evolvinto major assignments for the Shuttle propsion systems. This group also did the fore-thought and planning that later culminated major new space science programs, includthe High Energy Astronomy Observatories,Spacelab, and Space Telescope.The tenure of Dr. Wernher von Braun asDirector of the Marshall Center ended in 19when he assumed a new position at NASAHeadquarters. His long-time associate, Dr.Eberhard Rees, becam e Director and, untilretirement in 1973, ushered M arsha ll througdifficult period of reduced funding and manpower. During his term, emphasis at theCenter shifted from the Saturn program toSkylab and initial planning for the SpaceShuttle. His successor, Dr. Rocco A. Petronthen presided over the dramatic series ofSkylab missions in America's first space s tation. Since 1974 when Dr. William R. Lucasbecame Director, the Center has assumedmajor new responsibilities for the SpaceShuttle and other projects.As the Center looked ahead to the SpacShuttle, it was fully confident that the experence gained in the Saturn program would bwell applied to its next assignm ents. Withsome changes to meet the technical and magerial challenges of developing new propusion systems for a new launch vehicle,Marshall Space Flight Center had its bluepfor success.

Dedication of the orig inal Redstone TestStand at MSFC as a historic siteHuntwllle Tlmesphoto


26/93

"Houston...Tranquility Base here.The Eagle has landed."Neil Armstrong, July 20,1969


27/93

)Space ShuttleTHRUST Despite the feverish pace of Saturn develop-INTO SPACE ment and test activities, NASA was alreadyplanning a new launch vehicle for the nextgeneration. Impressive and powerful thoughthey were, the Sa turns had one d isadvantage:they were expendable. Used only once, theywere expensive to manufacture, stock in inven-tory, and use, and the cost per pound of pay-load delivered into orbit was high. When theagency began looking ahead to a m annedspace station as the next step beyond lunarexploration, alternatives to expendable rocketswere considered. The concept of a reusableSpace Shuttle was particularly appea ling as aneconomical vehicle to ferry people and sup-

plies to a nd from orbit. With its expertise inlarge launch vehicles and propuision systeit was on ly natural that M arshall Space FliCenter should play a m ajor role in the SpaShuttle program.By 1970,NASA initiated Space Shuttledevelopment activity. At first, M arsha ll washeavily involved in the program definitionphase leading to the current Shuttle configtion. When the final concept was se lected,Center became responsible for the develoment of the advanced propulsion systemsthe principal Shuttle elements -th e OrbiteMain Engines, Externa l Tank, an d SolidRocket Boosters- all but the O rbiter weredeveloped under Marshall Centermanagement.Much of the Shu ttle effort at Marshall wperformed by the same personnel and in tsame facilities that had served the Saturn gram so well. As Saturn activity subsided,these resources were mustered for the SpShuttle effort. Necessary adm inistrative anphysical changes occurred to accommodathe Shuttle program, but in general the Cecontinued its proven practices in the develment of large propulsion systems. M arshaSpace Flight Center was well prepared to the challenge of develop ing a new, improvthrust into space.

"You know when you ridea launch vehicle, thefuture standard launchvehicle of the UnitedStates of America, if itdoesn't work right, if allthose engines don't workright, you don't get veryfar down range. The SpaShuttle worked perfectly.was a beautiful thing."John YoungCommander, STS-1,1981

Readying the Orbiter Enterprisefor dynam ic tests at Marshall


28/93

e posed a number of technical chal-to Marshall engineers. Serving as bothvehicle, the Orbitered highly e fficient propulsion system s.hat cap ability best be achieved?nes? By external boo sters? Byon of both? How could enoug h fuelwithou t burdening thewith em pty tanks in flight? How couldciency be improved to get the m ostrom every gallon?For Saturn vehicles, the answ er to theseons was e xpendab le booster stages thatded thrust and then were discarded . Thehuttle, however, had to mee t a new require-ment- eusability- nd that introduced a hostf new questions. What sort of rocket enginecould withstand repeated use? How much ofhe propulsion system could be recycled andreused on successive flights? What m aterialscould survive the rigors of repe ated launchesand reentries?For each of the propulsion elements, theMarshall Center d eveloped unique solutions.The end product was a totally new laun chvehicle; its track record to da te is just as Iimpressive as that of the Sa turns.The Space Sh uttle Main Engines are themost advanced cryogenic liquid-fue led rocketengines ever built. From the outse t, it was

Ascent

moff

Landing

External TankLSolld RocketBooste~s---

Space ShuffleMain Engines- - ,


29/93

recognized that the Main Engines required thegreatest technological advances of any ele-ment in the Shuttle program. The three high-pressure engines clustered in the tail of theOrbiter each provide almost a half millionpounds of thrust, for a total thrust equal to thatof the eight-engine Saturn I first stage. UnlikeSaturn engines, the Shuttle Main Engines canbe throttled over a range from 65% to 109%oftheir rated power. Thus, the engine thrust canbe adjusted to meet different mission needs.The design goal for each engine is multiplestarts and a total firing lifetime of 71/2hours, ascompared to the SaturnJ-2 engine's lifetimeof about 8 minutes. The engines are gimballedso they can be used to steer the Shuttle aswell as boost it into orbit.

To get very high performance from anengine compact enough that it would notencumber the Orbiter or diminish its desiredpayload capability, Marshall worked closelywith its prime contractor, the Rocketdyne Divi-sion of Rockwell International. The greatestproblem was to develop the combustiondevices and complex turbomachinery -thepumps, turbines, seals, and bearings -thatcould contain and deliver propellants to theengines at pressures several times greaterthan in the Saturn engines. The Shuttle enginecomponents must endure more severe internalenvironments than any rocket engine everbuilt. Working out the details of this new high-pressure system was difficult and time-con-suming, but the resultant engines represent a

significant advance in the state of the art.The Shuttle Main Engine is the first propul-

sion system with a computer mounted directlyon the engine to control its operation. This dig-ital computer accepts commands from theOrbiter for start preparation, engine start,thrust level changes, and shutdown. The con-troller also monitors engine operation and canautomatically make corrective adjustments orshut down the engine safely. Advances in elec-tronic circuitry were required for the addition ofthis unit to a rocket engine. Because it oper-ates in a severe environment, special attentionwas paid to the design and packaging of theelectronics during an extensive design verifica-tion program.

Improved fuel efficiency was achieved byan ingenious staged combustion cycle neverbefore used in rocket engines. In this two-stage process, exhaust gases are recycled forgreater combustion efficiency; part of the fuelis combusted in preburners to drive the tur-bines, after which the exhaust gases are chan-neled into the main combustion chamber forfull combustion at higher temperatures with thebalance of the propellants. The rapid mixing ofpropellants under high pressure is so completethat a 99% combustion efficiency is attained.Even though they are extremely efficient,the three Main Engines consume a tremen-dous quantity of propellant, and the tank thatfeeds them is much larger than the Orbiteritself. Marshall also was responsible for devel-oping the External Tank, a massive container

Space Shuttle Main Engine- he most advancedliquid-fueled rocket engineever built.

Test firing of single SpaceShuttle Main Engine atNational Space TechnoloLaboratories in Mississip

Roll-out of a new External Tank at theMichoud Assembly Facility in Louisiana


30/93

almost as tall as the Center's main officebuilding. The External Tank actually containstwo tanks, one for liquid hydrogen and one forliquid oxygen, and a plumbing system thatsupplies propellants to the Main Engines ofthe Orbiter.

The External Tank presented a variety oftechnical problems, both as a fuel tank and asthe structural backbone of the entire Shuttleassembly. Standing 154 feet tall with a 27-footdiameter, the External Tank is a towering struc-ture; fully loaded, it contains more than a halfmillion gallons of propellant and weighs morethan one and a half million pounds. Marshallpersonnel worked closely with the prime con-tractor, the Martin Marietta Corporation, todevise appropriate design solutions for its unu-sual requirements.

The Center's prior experience on theSaturnV second stage was directly applicableto the cryogenic propellant design require-ments of the External Tank. To maintain theextremely low temperature necessary for theliquid hydrogen, the exterior skin of the tankwas covered with about an inch of epoxyspray-on foam insulation. This thermal wallreduces heat into the tank and also reducesfrost and ice formation on the tank after propel-lants are loaded. The tank is further protectedin critical areas from the severe aerodynamicheating during flight by a localized ablativeundercoat that dissipates heat as it charsaway.

Structurally, the External Tank is attachedto the Orbiter and the Solid Rocket Boosters.The load-bearing unction, both on the launchpad and during liftoff and ascent, was a majordesign driver. Engineers devised several solu-tions to make the tank as strong and as light-weight as possible. The aluminum alloystructure was designed to handle complexloads, and the problem of propellant sloshingin the tanks was solved with baffles to avoidinstabilities hat could affect the Shuttle's flight.

Another important design considerationwas the fact that the External Tank is not reus-able. Therefore, its design must be simple andits cost minimal. Solutions to these require-ments included locating the fluid controls andvalves in the Orbiter and drawing power for theelectronics and instrumentation from theOrbiter. With these economies, expendablehardware has been minimized.

The External Tank is manufactured at theMichoud Assembly Facility by Martin Mariettaunder Marshall Center management. Newtooling, such as a welding fixture half the sp4anof a football field, was required to handle pro-duction of the huge tank. Eventually, produc-tion of 24 tanks per year is planned. The bargetransportation system developed to deliverSaturn stages is now used to transport Exter-nal Tanks to the launch sites.

Preparing to mate th eExternal Tank and SolidRocket Boo sters atKennedy Space Center,Florida


31/93

Lowering Solid Rocket Booster into MSFCstructural test stand

The Solid Rocket Boosters are the firstsolid propellant rockets built for a mannedspace vehicle and the largest solid rocketsever flown. Burning for approximately two mi:Utes, each booster produces almost three m..lion pounds of thrust to augment the Shuttle'smain propulsion system during liftoff. Theboosters also help to steer the Shuttle duringthe critical first phase of ascent. The 11-tonboaster rocket nozzle is the largest movablenozzle ever used. The Solid Rocket Boosterswere designed as an in-house Marshall Centerproject, with United Space Boosters as theassembly and refurbishment contractor. TheSolid Rocket Motor is provided by the MortonThiokol Corporation.

The Solid Rocket Boosters are deceptivelysimple in appearance, considering their var-ious functions. On the launch pad, the boost-ers support the entire Shuttle assembly. Inflight, they provide six million pounds of thrustand respond to the Orbiter's guidance andcontrol computer to maintain the Shuttle'scourse. At burnout, the boosters separate fromthe External Tank and drop by parachute tothe ocean for recovery and subsequentrefurbishment.

The major design drivers for the SolidRocket Boosters were high thrust and reuse.The desired thrust was achieved by usingstate-of-the-artsolid propellant and by using a ~ ~ ~ ~long cylindrical motor with a specific core and reuse

Newly developedfilament-wound motorcase for Solid RocketBooster segments


32/93

design that allows the propellant to burn in acarefully controlled manner.

The requirement for reusability dictateddurable materials and construction, which ledto several innovations. Paints, coatings, andsealants were extensively tested and appliedto surfaces of the booster structure to precludecorrosion of the hardware exposed to theharsh seawater environment. Specificationscalled for motor case segments that could beused 20 times. To achieve this durability, engi-neers selected a weld-free case formed by acontinuous flow-forming process. Machiningand heat treatment of the massive motor casesegments also were major technical efforts.

Reusability also meant making provisionsfor retrieval and refurbishment. The boosterscontain a complete recovery subsystem thatincludes parachutes, beacons, lights, and *owfixtures. The 136-foot diameter main para-chutes are the largest ribbon parachutes everused in an operational system, and the SolidRocket Boosters are the largest objects everrecovered by parachute. The boosters aredesigned to survive water impact at almost 60miles per hour and maintain flotation with mini-mal damage.

Besides fulfilling its primary responsibilitiesfor propulsion systems, Marshall supportedmany other efforts in Shuttle systems engi-neering and analysis. The Center's technicalcompetence in materials science, thermalengineering, structural dynamics, aerodynam-ics, guidance and navigation, orbital mechan-ics, systems testing, and systems integrationall proved valuable to the overall Shuttle devel-opment program. Rigorous testing and a scoreof successful launches attest to the designachievement of the Shuttle propulsionsystems.

TestingShuttle test activities were a major responsibil-ity of the Marshall Space Flight Center forseveral years in the late 1970's. Both in Hunts-ville and at the related NASA facilities in Loui-siana and Mississippi, as well as at contractorsites around the country, Marshall personnelparticipated in many development and qualifi-cation tests. Whether they worked with individ-ual components within a laboratory orparticipated in engine static firings or dynamictests of the mated Shuttle elements, thesepeople held to the standard of excellence nec-essary for a successful Shuttle program. Longbefore the first Shuttle launch on April 12,

Solid Rocket Booster- helargest solid rocket motorever flown and the firstdesigned for reuse.

THRUSTINTO SPACE

Test firing of Solid RocketMotor at M orton Thiokol1981, Marshall had built confidence in the pro- facility in Utahpulsion systems.Preparing for and coordinating the many

different test programs was a significant tech-nical challenge. Rather than build new testfacilities for the massive Shuttle elements,Marshall modified existing resources. Test fix-tures and equipment that had stood idle sincethe Saturn era were revived and remodeled tosupport various Shuttle test efforts. In addi-tion, special new equipment was constructed.

The busiest year was 1978, when theExternal Tank structural and vibration tests,the Solid Rocket Booster structural tests, andthe Mated Vertical Ground Vibration Testswere done in Huntsville by Marshall Centeremployees. Meanwhile, single engine testsand main propulsion system cluster firingswere in progress at the National Space Tech-nology Laboratories (formerly Marshall's Mis-sissippi Test Facility). Solid Rocket Motor testswere underway in Utah, and subsystemstests, such as checkout of the booster para-chutes, were being completed elsewhere.Marshall played a prominent role in the year-


33/93

Arrival of Enterprise at Marshall for year-long test series

The Space Shuttle - alaunch vehicle, cargocarrier, service station,research lab, and home inspace.

Congressman Ronnie~ l i ~ ~ oouring Marshallduring Shuttle ,test period

long Mated Vertical Ground Vibra tion Tesgram, the critical evaluation of the entire tle complement- Orbiter, Tank, and Boo sassemb led for the first time. The phased sequence began in March of 1978when tOrbiter Enterprise arrived at M arsha ll andgreeted by throngs of em ployees and citiThe Orbiter was ho isted into the m odifiedDynam ic Test Stand o riginally built for S aV testing, mated first to an Extern al Tanksubjected to vibration frequencies com pato those expected during launch and ascSeveral months later, the Solid R ocket Boers were added for tests of the entire Shuassembly. The test series confirmed the stural interfaces and mating of the entire Stle system and allowed m athematical moused to predict the Shuttle's respons e to tions in flight to be adjusted so that e ffectfuture flight environments could be pre dicadequately prior to launch. Marshall manand conducted this important test prograwith support from the Shuttle contractorsConcurrently, both the E xterna l Tank athe Solid Rocket Boosters underwent indpendent structural tests. Thes e activitiesoccurred in Marshall's test stands an d in tBuilding 4619 test facility, all formerly u setest Saturn stages. In add ition, captive firof a 6.4% scale m ode l Shu ttle enabled enneers to determine the lau nch acoustic eronment and its effects on both the vehiclthe launch pad at Kennedy Space Center

ABOVE: MSFC test control engineer puttingShuttle elements th rough v ibration testsRIGHT: Prepa ration for Mated VerticalGround Vibration Tests


34/93

le model firings also influenced launch padfor the new western launch site

nberg Air Force Base in California.Marshall's other principal test responsibility

elopment and later for flight qualification.f propulsion system testing wasest series of cluster fir-

es were mounted tod fired simultaneously

e drawing propellants from an actual Exter-1977,

d not only the operational compatibility ofalsoant loading procedures and propellant

ms. In addition, Marshall establishedto test and verify the

through simulations of all operatingFrom earliest development through actual

l Center supervision. These test pro-

rous testing has always been a hallmark

e into the operational era. Marshall per-: launch support and production. (An

nt of scientific payloads for Shuttletext.)

The Huntsville Operations Support Center4663 is a hub of activity

a operations room and now is capa-f secured operations to support Depart-of Defense missions. From the HOSC,

s of theion systems; via a sophisticated com-

ork to guaran-le. Evalua-

f flight data is a crucial activity not onlyrt but also to assure that

flights can be safely made.Marshall is responsible or the continuedof External Tanks at the Michoud

To manage its manufactur-

ing enterprise, the Center engages in produc-tion planning, readiness reviews, andtechnology improvements on the productionand assembly lines to reduce costs. Marshallis meeting the new challenge of mass produc-ing high-quality hardware and doing it onschedule and with decreasing costs.

After a mission, the Solid Rocket Boostersare recovered and refurbished. Postflightactivities include engineering assessments ofthe wear-and-tear on the hardware and neces-sary repairs. Marshall engineers have devisedtechniques to diminish impact damage to theboosters and to streamline refurbishment oper-ations for fast turn-around between missions.

Another in a long series ofsuccessful Space S huttlelaunches

Engineers on duty in the HOSC duringSpac e S huttle missions


35/93

)Shuttle Improvements )Shuttle Legacies

Ongoing engine researchand technology develop-ment at Marshall

Shuttle responsibilities did not end with devel-opment of operational Main Engines, ExternalTanks, and Solid Rocket Boosters. Instead,Marshall is engaged in ongoing technologyadvancement to improve the Shuttle propul-sion systems at reduced costs. In various labo-ratories around the Center, engineeringevaluations of Shuttle performance continueas Marshall's experts investigate ways to makea proven product less costly.

The two primary challenges are to increasethe Shuttle's payload-carrying capability and toimprove the Shuttle's performance. To meetthe first challenge, Marshall engaged in aweight-reduction campaign to trim poundsfrom propulsion elements in order to carryheavier payloads into orbit. A lightweightExternal Tank was developed by removingsome insulation, trimming material from somestructural elements, and using stronger mate-rials where possible; this tank is already inuse. The Center also developed lighter weightsteel motor cases for the Solid Rocket Boost-ers and an innovative filament-wound casethat is even lighter and stronger. For improvedeconomics and performance, Marshall is alsomanaging the development of a Main Enginewith a longer flight lifetime.

The design of Shuttle propulsion elementscontinues to be refined through Marshall'songoing flight certification program; many ofthe improvements have been installed and arenow in use. The continuing advancement ofShuttle technology is as important and chal-lenging as the original design and develop-ment efforts.

Shuttle improvements studied inMarshall's engineering laboratories

In 1981, Marshall and the nation once agawatched expectantly as a new launch vehthe Space Shuttle, rose from the pad. Thsuccessful first flight with the Orbiter Columintroduced the era of the Space TransportaSystem and a continuing series of Shuttle msions. Three other Orbiters-Challenger, Dcovery, and Atlantis- oon joined the fleet,Americans felt new pride in the triumphs ofspace program.

The Shuttle development effort evolvenaturally out of the Saturn experience in llaunch vehicles and propulsion systems.Marshall continued its close working relatship with contractors and maintained its stechnical competence in the relevant enging disciplines. The Center also continuedsuccessful managerial practices. Howevecertain changes in NASA's philosophy anresources challenged Marshall in new waDuring the Shuttle period, Marshall SpaceFlight Center became a leaner, stronger itution as it adapted to these changes.

The principal philosophical change wanecessity of reuse. In a time of declining bgets and increased awareness of limitedresources, reusability was a high priority.Marshall met the technical challenge of doping durable space hardware that could recycled for many missions. Despite delaalong the way, the Shuttle development pgram proceeded successfully.

The achievement was especially noteworthy because the Center also was taskwith the administrative challenge of reassing facilities and personnel. As Saturn wotapered off and Marshall became involvedother projects, the Center had to reallocamany of its resources. Major reorganizatioccurred as leadership passed from Dr.von Braun in 1970 to three successors in years. From 1965, the peak year of Saturnactivity, to the first year of Shuttle activity 1970, Marshall lost almost 20% of its civilvice work force as federal budget cuts slathe Center's funding in half. This trend conued well into the 1970's until the budget a

The Space Shuttle mark-edly expands man's abilto do things in space atlower cost, more often,and more effectively thaever before.


36/93

evels tabilized ithstaffat approxi-0%of thePeakSaturnYear'Dr.W. R. Lucas,whobecameCentern 1974, emarkedhatMarshall adtsyearsof crisiswith ts commitmentntact. he Centermanagedowith he reductions ndstill ackleveryrojects.Meanwhile,heShuttle ndeavornflu-heCenter's ork n spacescience ndmanned rbital ystems.Developmentf aapable f routine ccess o spacepenedmanypossibilitiesor usingspaceas alaboratory ndworkplace.The Center's ever-opment ctivityn flightexperiments,bserva-tories, ndbasic esearch nd echnologyacceleratedoticeablyuringhi speriod.Marshall lsodevoted onsiderablettentionto manned paceactivity servicing pace-craft,assemblingargestructures, oing

experimentsmadepossible y heShuttle.A work prace anJ er,yey e r e r b f r

Twentieth-centurypilgrimage


37/93

THRUSTINTO SPACE

Deployment of NASA's #racking and Data RelaySatellite (TDRS) and its bInertial Upper Stage from ,the Shuttle payload bay i '' I

-

OMV simulator in MSFC'steleoperation and roboticsresearch laboratory

Concept for an Orbital Maneuvering Vehicleto ferry payloads to and from the Shuttle inlow-Earth orbit

)AdvancedTransportation SystemsIn 1977, Marshall acquired responsibilitiesanother propulsion element, an upper stagboost payloads to higher orb its or to sendspacecraft on interplanetary voyages. Whilthe Air Force had primary responsibility ordevelopment of an Inertial Upper Stage,Marshall became NASA's managem ent ancoordination center, providing the agency'sdesign and operational requirements to theForce and participating n the developmentwo upper stage configurations for NASA msions. Marshall participated n key designreviews, interface working groups, and testactivities for the NASA upper stageconfigurations.NASA's first use of the upper stage tolaunch a Tracking and Data Relay Satellite1983was only a partial success; the sa telldid not reach the desired orbit and furtherlaunches were delayed pending evaluationmodification of the boosters. The upper stasubsequently performed satisfac torily on amission in 1985.The Center also became involved in twcommercial ventures for upper stages. ForShuttle missions, Marsha ll monitors the Paload Assist Module developed independenby McDonnell Douglas. A larger Transfer OStage under development by the Orb ital Sences Corporation is also being mon itoredMarshall. These upper stages broaden thevariety of payloads that can be placed in orfrom the Shuttle.

What kinds of cargo carriers and peop lmovers are needed in the Space Station eAs commercial activity in space increases people living and working there, the demanfor transportation service will m ultiply. Planand concept studies are well under way atMarshall Space F light Center to forecast thspace transportation needs of the future andevelop appropriate vehicles.In the future, different vehicles will beneeded for travel between the ground, loworbit, high orbit, and beyond. In general,Marshall planners foresee three new classof vehicles to satisfy different mission requments: Orbital Maneuvering Vehicles, OrbiTransfer Vehicles, and advanced large-lift cles. These new veh icles will augment thecapabilities of the proven Space Shuttle, wwill continue to offer routine passenger andcargo service between the ground and lowEarth orbit.The idea of an Orbital Maneuvering Vecle, a space "tug," has been considered aCenter for several years. In 1977, Marshalwas authorized to define a Teleoperator


38/93

Retrieval System, a remotely controlled propul-sive vehicle that could rendezvous with anorbiting spacecraft, grapple it, and move itelsewhere. Originally conceived for future on-orbit servicing missions, the teleoperator wasconsidered for use in a possible Skylab rescueattempt. Development activity accelerated tomeet a pressing schedule as Skylab's orbitdecayed more rapidly than anticipated.Work on the Teleoperator Retrieval Systemprogressed through rendezvous and dockingsimulations as Marshall investigated suitablehardware fixtures and remote control proce-dures. Tbe Center also engaged in a numberof studies to determine the visual and manipu-lator aids needed for remote operations; televi-sion systems, hand controls, and end effectorsreceived careful attention. Although the SkylabreboosVdeboost mission did not occur, theplanning activity energized teleoperatorresearch and technology at the Center. Thecapability for orbital docking simulation wasexpanded to include a unique six degree-of-freedom motion system for evaluation of dock-ing mechanisms.The Orbital Maneuvering Vehicle nowunder study is an improved version of thisspace tug with a larger service role than origi-nally foreseen. In addition to satellite retrievaland delivery tasks, this vehicle might performremote maintenance, assembly, and logisticstasks to service free-flying spacecraft and alsosupport Space Station activities.Marshall Space Flight Center has been apioneer in advanced teleoperation and roboticstechnology research for more than a decade.The Center is continuing this research in anew evaluation laboratory opened in 1984.

"We will undoubtedlycontinue to explore nearerspace. We will keep goingto the moon, maybe oneday build a permanentcamp on the moon, andthen go on to Mars andVenus."Dr. Wernher von Braun, 1967

This unique facility houses a 4,000 square footprecision flat floor and air bearing vehicles; it isused as a test bed for remotely controlled vehi-cles. Simulations in the facility serve to evalu-ate remote systems concepts and also to trainoperators. The laboratory will play a prominentrole as an Qrbital Maneuvering Vehiclesimulator.Orbital Transfer Vehicles are required todeliver some orbital payloads, including peo-ple, to higher altitudes beyond the Shuttle'srange, which is limitedto about 600 miles, andto launch interplanetary probes from Earthorbit. They also can be used to ferry space-craft between stationary geosynchronous orbitat 22,000 miles and the Space Station in low-Earth orbit for servicing or refurbishment, orthey can be used to carry work crews to ser-vice distant satellites.Over the years, Marshall engineers haveconsidered various concepts for advancedtransportation systems to meet these needsfor greater payload capability. Among the mostpromising were a Spinning Solid Upper Stagefor deliveries to geosynchronous orbit and aSolar Electric Propulsion Stage that generatedand used its own power. The Center is nowinvestigating several concepts for aeroassistedbraking that would enable a returning OrbitalTransfer Vehicle to slow its speed without rely-ing on an engine. Although no particular hard-ware configuration has yet been selected, the

Concepts for Orbltal7kansfer Vehlcles to ferrypayloads, supplies, andastronauts between low-Earth and geosynchronousorbits


39/93

THRUST planning studies draw upon M arshall's residentINTO SPACE propulsion and vehicle design talents.The Center has also given much attentionto complementary launch vehic~ es erivedfrom the basic Space Shu ttle propulsion ele-ments. These m ay serve as logistical supplyvehicles to carry needed ma terials and equip-

ment into orbit. The challenge in this effort is toadapt existing designs for missions requiringvastly greater payload lift, perhaps a millionpounds of payload as com pared to theShuttle's 65,000 pound capability. Variouscombinations of m odified engines, tanks, andboosters are being considered. Although nospecific concept has been authorized fordevelopment yet, the thrust of these s tudies isto augment the capabilities of the Shuttle forunmanned delivery of payloads and for launchof extremely heavy cargo.)A Glimpse of the Future

Very soon, space will be a busy work place.Traffic will increase noticeably as peop le,materials, and equipment are routinely trans-ported back and forth between the ground andlow-Earth orbit. Traffic will also begin to flow toand from more distant regions of space - eo-synchronous orbit, the moon, the neighboring

Side-mount Shuttle-Derived Vehicle

planets. Talk of manned lunar colonies or amanned expedition to Mars is no more idletoday than talk of a Space Station was 15 yeago. Now the Space Station is becoming a rity; what about the other dreams?Sophisticated as it is, the current SpaceShuttle is but the first gene ration model. Italone cannot m eet all the transpo rtation neof the future. New vehicle models are yet todesigned and developed. Like automobilesthey will progressively become more efficiemore comfortable, more serviceable.Consider how rapidly propulsion systemand launch vehicles have evolved. It took oa decade to develop and prove the transpotion system that safely carried people to themoon and back. In another decade , a reusspace vehicle was in service . What was oninconceivable- paceflight- s now taken granted.Although it is now possible to send peoback and forth, to place satellites in desiredorbits, to dep loy and retrieve pay loads , thesachievements are rudimentary compared towhat can be done. Despite the advances orecent years, technology has not yetapproached the limits of what is theoretica lpossible.Marshall is NASA's primary Center for ppulsion systems development, and many othe test facilities here are unmatched. Marsalso has unique facilities for the developmeof large structural systems and impressive oratory resources in the various engineerindisciplines. The necessa ry tools are availahere to meet the cha llenge s of future spacetransportation systems.Marshall people can and will m ake newstrides in the technolog ies for advanced prpulsion systems and launch vehicles. W herthe first quarter-century results were theSaturns and the Shuttle, in the next quarteMarshall may produce a fleet of quite differvehicles - owering ones for heavy-liftlaunches, agile ones for orbital maneuverinpowerful but lightweight ones for orbit transfers, vehicles that run on exotic fuels or novengines, robotic vehicles, pe rhaps even copact models for manned use. The possibiliare exciting and unlimited.As it looks toward future transportation space, Marshall is exploiting its wea lth ofexperience and im agination. Drawing upontechnical expertise of its staff in all the engneering disciplines, this Center expects thethrust into space to remain one of its prim aoccupations and achievements in the yearsahead.


40/93

"You and I have beenprivileged to live and par-ticipate in a unique periodin man's history, a periodof explosive technologicaladvancement that hasbeen unequaled in anyother epoch."Dr.W. R. Lucas

In-line Shuttle-Derived Vehicle

Concept for new Heavy-Lift Launch Vehicle

Propulsion and transportation for the future:a high priority at Marshall


41/93


42/93

launchid peo-:e?urpose' From ai view,we can:e that isThereof our~ n deo-physical observations, an unobstructed view othe heavens for astronomical observations, amicrogravity environment for experiments inlife sciences and materials science, and directexposure to the radiation and vacuum ofspace. Thus, space is a unique laboratory.NASA's charter explicitly states that "activitiesin space should be devoted to peaceful pur-poses for the benefit of all mankind." Spacescience research extends the frontiers of

knowledge in accordance with tha t charter.Even while they were a ffiliated with m ilitarjprojects, the early rocket pioneers consideredthe potential uses of rockets for scientificresearch in space. It seemed quite p ractical toreplace miss ile warheads w ith scientific experiments or to develop more powerful vehicles toplace satellites, laboratories, and people intospace. Dr. Wernher von Braun rem arked thatthe driving ambition of h is colleagues had beeto engineer rockets for sc ientif ic research. Wit1a singleness of purpose , they were dedicatedto the evolution of space flight for the explora-tion of the universe.The Marshall Center's involvement in spacscience can be traced to the launch ofAmerica's first satellite, Explorer I n 1958,aboard the