A Rocket for Manned Lunar

1959 IRE TRANSACTIONS ON SPACE ELECTRONICS AND TELEMETRY 155

A Rocket for Manned Lunar Exploration*M. W. ROSENt AND F. C. SCHWENKt

Summary-The exploration of the moon is within view today. ments can transmit their findings back to earth, why doIf it may be assumed that Project Mercury in the U. S. A. and we need a man in space? Since an instrumeilt can fail,similar efforts by the U. S. S. R. will establish that man can existfor limited periods of time in space, then a trip to the moon requires we makeit redundant. If it needs adjusting, we make itmainly the design, construction and proving of a large rocket ve- self-adjusting. Certainly it can be built to withstand ahicle. In one concept of a manned lunar vehicle, the entire mission, greater range of temperature, pressure, acceleration, andthe trip to the moon and the return, is staged on the earth's surface. radiation than the sensitive body of man.A highly competitive technique is to stage the lunar mission by But we have a tendency to look only at one side of thisrfueling in a low earth orbit. This would permit the use of a smaller

.

. e blaunching vehicle but would require development of orbital ren- picture. Because our knowledge ofdistant celestial bodiesdezvous techniques. is so meager, we tend to magnify the importance of the

This paper presents a parametric study of vehicle size for the simple data that can be most readily obtained by instru-direct-flight manned lunar mission. The main parameter is the ments. We overlook that, if an instrument can do one ortake-off thrust which is influenced by many factors, principally the several things, there are thousands, indeed millions, ofpropellants in the several stages and the flight trajectory. A close . . . .Tchoice exists in the second stage where conventional and high- things itscannotido to thit blntly,tno sensiorenergy propellants are compared. The size of the final stage and array of instruments exists that can duplicate the sensinghence the entire vehicle is governed mainly by the method of capabilities of a man. When to this is added man'sapproach to the earth's surface, whether the approach is made at capability to record, remember, interpret, and discrimi-elliptic, parabolic or hyperbolic velocities. The various design nate, we see how paltry are the powers of the most sophisti-choices are applied to an illustrative vehicle configuration. c

cated mechanical substitute.If this line of reasoning is accepted, there remains the

INTRODUCTION question of timing and the argument runs, "InstrumentsV HEN one views the history of exploration he first-men later." Many scientists feel that years of

finds that the dominant role was played by man. instrumented exploration are necessary before a firstMen, many of them, explored the coasts and manned mission. The standard program is now quite

interior of America; fewer numbers endured Arctic cold famiiliar. First comes a close approach or hard impact inand coped with other physical hazards to reach previously which measurements are made of the magnetic field andinaccessible regions of the earth. Hence, it is not sur- the local radiation; perhaps a few photographs are taken.prising that exploration is linked in history with the names Then come vehicles that orbit around the moon doingof the men who accomplished it: Columbus, Balboa, extensive reconnaissance. Finally, instrumented packagesPeary, Amundsen, to nlame a few. are set down on the moon (so-called soft landing) toOnly in our time has it seemed important to support examine closely the lunar surface. At first the packages

or defend this point of view. We have sought reasons are stationary but later they are mobile. A decade orto Justify sending men into space to explore the moon more of intensive engineering development is envisionedand the planets. Because they are merely expressions Of to make possible this type of exploration, and even nowa desire, most of these sought-after reasons are un- we are designing rockets that can carry the freight:convincing, such as the vapid reason, "because the moon Vega, Centaur and Saturn.and the planets are there." It is argued here that we would learn much more at an

Indeed, for some ill-defined reason centered mainly earlier date by a bold and immediate approach to mannedaround national prestige, there are many who maintain lunar exploration. Moreover, instruments should be usedthat most of space exploration should be done with mainly for a certain type of reconnaissance; i.e., toinstruments, and that men should be sent only after provide the information necessary to attempt a mannedyears of unmanned examination. lunar landing. The early attempts will not be without

Moreover, a distinction is being drawn between manned risk of failure and probable loss of life. How could it beexploration and scientific exploration. Not that sending otherwise? Exploration implies risk and manned explor-a man into space is unscientific, but perhaps not scientific ation implies risk of life. The names of those who failedenough. After all, a man cannot see ultraviolet light or are numerous though not always well remembered. sScottsense magnetic fields, nor can he detect cosmic rays. reached the South Pole one month after Amundsen, butThese things are done by instruments, and if the instru- died with four of his men on the return trip. Nungesser

and Coli took off from Paris and were lost in the Atlantictwelve days before Lindbergh left New York.

* Manuscript received by the PGSET, September 3, 1959. ,T7he argument that we cannot afford the risk of humanPresented at the Tenth International AstronaUtiCal FederatiOn COn- life to explore the moon is historically ui#sound; more-gress, London, England, 1959.

t Nati. Aeronautics and Space Admin., Washington, D. C. over, it is economically unsound. The attempt to duplicate

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156 IRE TRANSACTIONS ON SPACE ELECTRONICS AND TELEMETRY December

with instruments what could be accomplished by a few a long time to reach operational status. In fact, the timemen on the moon would be immeasurably more ex- required may be too long to satisfy those who wish to seepensive. a man on the moon as soon as possible. We believe, how-

In this paper we examine the type of vehicle required ever, that space exploration of all types will require thefor manned lunar exploration by the simplest operational development of the larger vehicle that is capable of directmethod, a direct flight to the moon and a direct return to flight to the moon. For example, if a manned lunar landingthe earth. First, the direct flight method is compared with is achieved first by the rendezvous method, the supply oforbital rendezvous. Then, various factors influencing the a lunar base will be accomplished more readily by asize of the vehicle are examined. Finally, a typical vehicle direct-flight vehicle.and its employment are described.

DIRECT-FLIGHT VEHICLE DESIGN FACTORSDIRECTFLIGHT OR ORBITALRENDEZVOUS Having set our sights on a direct-flight vehiele; we wish

There are two important approaches among many for to examine some of the factors that affect its design and,achieving a manned lunar landing. One approach is the ultimately, to describe a vehicle suitable for a round tripdirect-flight method that presupposes the development to the moon.of a very large vehicle which has complete capability for First, we must define the mission. A two and one-halfthe mission. The other is orbital rendezvous which employs day flight from earth to moon is chosen. A shorter timea smaller booster and involves accumulating in an earth minimizes effects of errors in burnout velocity, butorbit the required mass of hardware and fuel for escaping demands more total impulse. The first three stagesfrom orbit, landing on the moon, and returning to earth. accelerate the payload and remaining stages to an inertialEach method has many supporters among rocket engineers. velocity of 36,000 feet per second. After coasting to theAlthough this paper describes a direct-flight vehicle, the vicinity of the moon, the fourth stage lowers the remainderrendezvous method is a worthy contender for providing of the vehicle to a landing on the moon. At the time ofthe earliest capability for a manned lunar landing. departure, the fifth stage propels the vehicle toward theAs far as booster availability is concerned, the orbital earth. After two and one-half days, the payload approaches

rendezvous method leads the direct-flight approach since the earth. Here there is a choice; a sixth stage of propulsionthe smaller vehicle will be available earlier. However, can be employed to slow the payload to orbital speed, orbooster availability is only a small part of the mission the vehicle can enter the earth's atmosphere at hyperbolicpicture. Techniques must be developed for orbital velocity. We shall delay discussion of this choice untilrendezvous, which is an operation that poses many later, but assume for the moment that hyperbolic re-entryproblems. If we consider launching from a nonequatorial can be tolerated as we discuss some other factors relatedbase, then accurate timing of the launching is required to to the direct flight vehicle.establish coplanar orbits; otherwise, a plane change is Oine of the major concerns is the selection of propellantsrequired in the rendezvous maneuver. Plane changes are for the various stages. High-energy propellants, liquidcostly in payload and require added developments in oxygen, and liquid hydrogen, are most desirable to achieveguidance. Possibly, the rendezvous method requires the the mission with the least vehicle gross weight. Naturally,vast undertaking of an equatorial launch site to rid the this propellant combination can be used only if themethod of some of its complications and the strict re- necessary engines are available and if the techniques forquirement on launch time. Consequently, these factors handling liquid hydrogen are developed. We believe thatmay delay the orbital technique to a time long after that both these conditions can be met in the smaller stages.required for booster availability. Consequently, high-energy propellants were chosejn forAnother important factor is the number of vehicles the third and fourth stages of the vehicle.

required for the rendezvous method. To build up the For a return capsule weight of between 8000 and 9000capability in orbit for just one lunar vehicle, eight suc- pounds, we can show that the vehicle at lift-off mustcessful flights of the Saturn type booster are required. weigh more than 4 million pounds. A sea-level thrustSaturn is a vehicle that uses eight engines to produce over rating of over 6 million pounds is, therefore, a necessity.one million pounds of thrust at launch. In addition, a NASA is presently developing a rocket engine which iscrew of men would be needed in orbit to perform the capable of producing 1 million pounds of thrust withtasks of assembly, transferral of fuel, and vehicle check- liquid oxygen and kerosene propellants. A cluster ofout. Surely, the operation would be performed at least several of these engines is therefore the logical choice foronce to provide an unmanned test flight to the moon first-stage propulsion, a choice that also specifies liquidbefore a man is sent. If we include the need for a spare oxygen and kerosene as first-stage propellants.lunar vehicle, the result is that at least twenty-four Now we must decide on the propellants for the secondlaunchings of the Saturn booster mnust occur for the sole stage. Fig. 1 compares the payload variations with earthpurpose of the manned lunar landing. take-off thrust for two cases. In one case, high-energy

Admittedly, the development of a large vehicle with propellants are used in the second stage; in the other case,direct-flight capability will be costly and will require liquid oxygen and kerosene are the second-stage propel-


1959 Rosen and Schwenk: A Rocket for Manned Lunar Exploration 15720 - 20 11

I SECOND STAGEI20_

| PROPELLANTS FIFTH STAGE (LUNAR LAUNCH)PROPELLANTS

16016o 160. 8IloLM

LAUNHIGH ENERGY __ __ __ __UND0lg. HciH ENERgY0

'< 12 a._ 12

0 zo0/"e fr.ae

8r _ __ CNENTIONAL < 8w M ~~~~~~~~~~~~~CNVENTIONALW 0

-.0

__ 0I~~~~~~~~~~~~_w2 4

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158 IRE TRANSACTIONS ON SPACE ELECTRONICS AND TELEMETRY December16 T 0

RE-ENTRY AT HYPERBOLIC 19

tcr( SPED

wz

LA2CH_ SPEEDS ____ON__PO __ 011

40aLa.~~_

z~~~RETRO TO EARTH4 ORBITcn 7

4

0 117___II4 8 12 16 20 24LAUNCH THRUST- MILLIONS OF POUNDS

Fig. 3-Effect of re-entry method on the variation of payloadwith launch thrust.

Chapman3"4 of NASA describes the hyperbolic re-entryphenomena and corridors. He shows that the heating 44'-rates and heat absorbed are several times as great as inorbital decay of a non-lifting body, and that guidancerequirements are severe as far as path angle accuracy isconcerned. Chapman states that the tolerance on flightpath angle for proper entry into the atmosphere is approxi-mately one minute of arc at distances of 10 to 100 earth _ 220radii from the earth. These are formidable problems, butconsidering how ballistic missile reentry was solved once Fig. 4-Outline drawing of direct-flight vehicle.the problem could be stated, one expects that hyperbolicre-entry will yield to a similar treatment. TABLE I

WEIGHT BREAKDOWN FOR TYPICAL DIRECT-FLIGHT VEHICLETYPICAL DIRECT-FLIGHT VEHICLE- Stage 1 Weights Pounds

VEHICLE CHARACTERISTICS Launch 6,700,000Burn-out 2,0002000

In describing a typical direct-flight vehicle, our purpose Stage 5,000,000is to summarize the previous discussions on the various Stage 2 WeightsGross 1,700,000design factors. Fig. 4 shows an outline drawing of the Burn-Out 678,000typical direct-flight vehicle and Table I presents vehicle S Stage 1,100,000Sae3 Weightsweights. The vehicle stands about 220 feet high and the Gross 600,000first stage is 48 feet in diameter. The conical portion at the Burn-Out 146,000Stage 498,000top contains the landing or fourth stage, the take-off or Stage 4 Weights (Landing Rocket)fifth stage, and the manned capsule or payload. Upon Gross 102,000Burn-Out (on Moon) 49,100return to the earth, the payload will weigh 8000 pounds Propulsion, Tanks,including men, equipment, capsule, guidance and control, Landing Gear 13,100including

~~~~~~~~~~~~~~~~Payloadon Moon 36,000and parachute. Two or three men will constitute the crew. Stage 5 Weights (Return Rocket)

Six engines, each of 1.5 million pounds of thrust, power Gross 36,7000Burn-Out 13,700the first stage. Liquid oxygen and kerosene are carried in Propulsion and Tanks 3,800a cluster of seven tanks, each one 16 feet in diameter. Weight Returned to Earth 8,000One altitude version of the 1.5-million pound thrustengine propels the second stage. This stage uses a clusterof four 16-foot diameter tanks. The high-energy third stage also consists of a cluster of four of these 16-foot

tanks, and a thrust level of 600,000 pounds is produced3D. R. Chapman, "An Approximate Analytical MIethod for by four engines.

Studying Entry into Planetary Atmospheres,"2 Nati. Aeronautics The fourth or landing stage utilizes high-energy pro-and Space Admin., Washington, D. C., NACA TN4276- 1958.4D. R. Chapman, "On the Corridor and Associated Trajecto,ry pellants, and four throttleable engines provide the re-Accuracy for Entry of Manned Space Craft Into Planetary Atmos- qurd variationsoftrsfrthladnmnev.Tepheres," presented at the International Astronautical Federation quroftusfrthladnmnev.TeCongress, London, England; August 31-September 5, 1959. landing stage must have the capability for hovering to


1959 Rosen and Schwenk: A Rocket for Manned Lunar Exploration 159

allow final choice of a landing spot by the pilot. Approxi- Launching from the surface of the moon will be guidedmately one minute of maneuvering or hovering time is by an inertial system that is aligned and calibrated by theprovided. Retracted landing legs appear on the side of pilot on optical sightings of stars and earth. The properthe fourth stage. When extended for landing, the legs re-entry corridor in the atmosphere is reached by a combi-span a distance of 40 feet for purposes of stability. nation of optical sightings from the vehicle and earth-The fifth stage is placed in a cylindrical tube that based radio signals. During re-entry, the lift of the capsule

pierces the tankage of the landing stage. At take-off from is utilized to modify the trajectory such that the vehiclethe moon, the fifth stage slides out of the landing vehicle follows a prescribed deceleration program and landson rollers. We chose this arrangement because it presents within the recovery area. The first phase of the re-entrya vehicle with a low center of gravity which will reduce maneuver will utilize vehicle-contained guidance moni-any tendency for the vehicle to topple on the surface of tored from the earth. After the initial slow-down tothe moon. In addition, the propellant tanks of the spent orbital speeds, earth-based radar in the landing area willlanding stage which surround the fifth stage serve as control the vehicle.meteor bumpers and shielding against thermal radiation.Furthermore, no landing loads are transmitted through DESCRIPTION OF THE FLIGHTthe return stage, thus minimizing the danger of a rough Let us dismiss, for a few moments, considerations oflanding. time and space and imagine that we are on a PacificThe manned capsule is an enlarged version of the one Island some five to ten years in the future. The latest of a

used in Project Mercury. It is a truncated cone, with a series of Nova rockets stands erect in the launching area.maximum diameter of 12 feet and a height of 14 feet. Only a few men can be seen working on the rocket in con-Inside the capsule, two levels are provided. The lower trast to the hundreds that used to crowd the launch areaslevel contains contoured couches for the crew, controls, of the late fifties. For we have learned to make our rocketscommunications, and a folding air-lock for use on the less complicated and more reliable as we have increasedmoon. The upper level contains food, power supply, their size. No battery of speakers blares out the count.exploration gear, and work space. The outer surface of Instead each worker has a small transceiver attached tothe capsule is covered with ablative material for insulation his helmet through which he receives the count andagainst and removal of heat generated during atmospheric communicates with the blockhouse. Finally the 300-foot-re-entry. high gantry rolls away and the rocket is left standing

alone, poised for its launching. The six giant motors igniteGUIDANCE SYSTEMS in pairs while the rocket is held fast to the launch stand.

Guidance system requirements normally are divided Finally the umbilical cables drop away and the rocketinto three phases: initial, mid-course, and terminal. For rises with the roar of 9 million pounds of thrust (see Fig.this mission, we must provide these three functions for 5). The light of the exhaust illuminates the entire island.both the moon-bound and the earth-bound trips. In The rocket rises vertically for 10 seconds and then tiltsaddition, we should consider the pilot's capabilities to slightly to the east. It continues to burn for 135 secondsperform major guidance tasks or monitor an automatic to an altitude of 35 miles. Then it cuts off and separatessystem. At present, the latter is most reasonable, since to be recovered for later use. The second stage ignites im-we believe that an unmanned return vehicle, a spare, so mediately (Fig. 6) and burns for 177 seconds, acceleratingto speak, should be placed on the moon prior to the to a speed of 15,800 feet per second. Finally the thirdmanned flights to provide an escape route should the stage fires (see Fig. 7) along a path almost parallel to themanned vehicle be damaged upon landing. earth's surface, but at an altitude of about 150 miles.The initial guidance phase from launch to earth escape After third stage burnout, the cone-shaped vehicle coasts

can be accomplished with sufficient accuracy by inertial silently through cislunar space for 60 hours. As it ap-systems now under development. Mid-course guidance proaches the moon (see Fig. 8), the vehicle starts to turnby means of earth-based radio can direct the vehicle to under the influence of control jets to orient itself for thean accuracy of 50 miles for a lunar impact trajectory. descent to the lunar surface. The four braking rocketsThe terminal phase involves the final approach to the are now firing (see Fig. 9), maneuvering the vehicle towardmoon and the lunar-landing. These maneuvers require its selected landing area. The landing struts extendingvehicle-contained guidance; however, lunar-based radio from the side of the cone span 40 feet. The cone settlesbeacons will assist. A combination radar-optical system down slowly (see Fig. 10) and comes to rest on the moon.will sense altitude and velocity components relative to As the two occupants emerge (see Fig. 11), they see,the lunar surface. In all but the initial guidance phase 500 yards away, an exact duplicate of the vehicle that(during launching), the pilot can effectively monitor and brought them to the moon. This spare return vehicleoverride the automatic system if necessary. During the had been sent up one month earlier, had landed on themid-course phase, in particular, the pilot can make moon, checked itself out and radioed its state of readinessoptical observations of the lunar disk for distance and to earth. Farther away is the radio beacon sent to thepath angle measurements. The pilot will also be very moon a year earlier on a Centaur rocket to mark theeffective in the final phase of the landing on the moon. landing area.


160 IRE TRANSA ('TIONS ON SPACE ELECTR?ONI(CS AND TELEMERTI Y December

LUNARLNARETUR MISSON R:UR MISSIOLAUNCHIN6 C _ RING

Fig. .5 -Nova liaunchiiig. (C'oss weighlt, 6.700,000 l)bs.; thrltst, Fig. 6 Second stage fiiing: jettisoned fir'st stage tat bottonirncenter.",000,00( l)s.

UJNAR~~~~~~~~~~~~~UARETURN M~~~~~~~~~~~~~S ~R~-~PN ISX

ThIR0 STAGE FIRING T 1 STA

F'ig. 7 Thiird Stagefigieig; jettiSOned second stage at bottom center. Fig. 8 -Approach to mooni; vehlicle rot:atingungler j(t conitrol.

Fig. 9 I)escen t to luinar surface; b)raking rockets fi -imig.


Fig. 1 Lalndinig on themoohi. Rad(io beacon is at far iright. Fig. I I xploiing the mooll Spahire ret(lirn vehicle is il baekgrouid.

WNARRETURN MISSIONTAUEOFF FRM MQONWITH FIFTH STAGE

Fig. 12-Fifth stage taking off from moon. Fig. 1:3 lletiurin CaI)1isle orielitilig for lre-elitri . Spent fifth stalge isat let.t

F'ig. 141 --Capsile reii-eniters earthIi at iosphlere. Fig. 15 1I et iirn to earlh andI recovery at sea.


162 IRE TRANSAC'TIONS ON SPACE ELECTRONICS AND TELEMETRY December

How the two men occupy themselves during their 12 parachute is deployed which slowly lowers the capsuledays on the moon can be better described by those who to the ocean (see Fig. 15).have for years speculated about the lunar crust. If, at first glance, the preceding account appearsWhen they are ready to depart, the men re-enter the fanciful, it is because our thinking has not caught up with

capsule and fire the fifth stage (see Fig. 12), which uses the engineering advances of the last few years. What hasthe fourth stage as a launching stand. The final stage been presented here is based on a preliminary designburns for 220 seconds. Then starts the long 60-hour study of the type conducted by many agencies to assessreturn trip during which a few precisely timed corrective the feasibility of a vehicle design. All of the engines areblasts put the cone in the correct corridor for re-entry to either being developed or are programmed to be developedthe earth's atmosphere. Then the fifth-stage motor is in the next few years. No new or exotic fuels are required.discarded (see Fig. 13), and the cone begins its descent Indeed, our calculations reflect the sober degree of con-with careful control of its angle of attack. The cone servatism that should characterize a preliminary study.approaches the earth (Fig. 14), its ablative surface glow- We believe that feasibility has been shown. There remainsing from the heat of re-entry. At 30,000 feet a large now the intriguing task of doing the job.

Contemporary Plasma Physics*LOUIS GOLDt

Summary-The manifold aspects of plasma physics are briefly structure of the ionosphere has been undermined owingdescribed. The basic science and advanced technology embodied to rocket and satellite measurements of electron densityin this interdisciplinary field are delineated following an identifi- . 4cation of what constitutes a plasma. With regard to the former, in the upper atmosphere, for example.4 And so it goes.such highlights as the evolution of the method of adiabatic i Numerous conferences have already been held and manyvariants to deal with highly nonlinear properties of plasmas are more are currently being organized to record the rapidoffered. Hypersonics, high impulse fuel systems, the Sherwood progress. A spate of monographs has originated in con-program, nuclear explosives, and microwave tubes represent key nection with some of these conventions.areas in modem technology demanding more basic knowledge of

plsm itrcon.'- At the moment, a marked output of publications inplasma interactions. plasma physics has become apparent, this no doubt aidedINTRODUCTION immeasurably by the declassification of Sherwood. The

Russians, in fact, presented at the 1958 Geneva Con-P LASMA physics is inherently as ancient as the sun ference four volumes of collected works on plasmas.6

and the stars.' Yet only in recent times has it Thus, clearly the quest for controlled fusion has pro-begun to emerge as a significant area of natural vided a compelling impetus toward the growth of this

science.2 The knowledge from many of the basic sciences field.7 Of course, the forerunner was the H-bomb itself,and from even more numerous borderline disciplines is and this, along the general province of nuclear weaponry,being brought to bear on most complex problems associated imparts much stimulation; you no doubt have becomewith phenomena in ionized media. Here is a domain of cognizant of the Argus experiments and the high energyscientific challenge remarkable in its interdisciplinary radiation belts encircling the earth.8 The latter scientificflavor. discovery has been a direct consequence of the emergenceSuch natural phenomena as aurora, whistlers, sun of the space age. Our scientific and technological stature

spots, solar noise, cosmic rays, etc. have long resisted is being strained to the utmost as the national effort insensible explanation and now are hopefully in the process space-flight and missile technology proliferates.of being better understood.3 Our faith in the layered J. C. Seddon A. D. Pickar, and J. E. Jackson, "Continuous

electron density measurements up to 200 KM," J. Geophys. Res.,* Manuscript received by the PGSET, September 3, 1959. vol. 59, pp. 513-524; December, 1954.

Based on an address for colloquium by the Physics Dept. at North 5 R. K. M. Landshoff, Ed., "'Plasma in a MIagnetic Field,"Carolina State College, Raleigh, N. C., May 4, 1959. Stanford University Press, Stanford, C:alif., 1958.

t Project Matterhorn, Princeton University, Princeton, N. J.* 6 J. Turkevich, Trans. Ed., "Plasma Physics and the Problemformerly at Res. Div., Radiation, Inc., Orlando, Fla. of Controlled Thermonuclear Reacetions," Pergamon Press, to be

1 H. Alfven, "Cosmical Electrodynamics," Oxford University published.Press, New York, N. Y., 1950. 7 See papers from Convention on Thermonuclear Processes,

2 L. Spitzer, "Physics of Fully Ionized Gases," Interscience London, Eng., April 29-30, 1959, Special Supplement to Proc.Publishers, Inc., New York, N. Y., 1956. lEE, vol. 106, to be published.

3S. K. Mitra, "The Upper Atmosphere," 2nd edition, Calcutta, 8J. A. Van Allen, "Radiation belts around the earth," Sci. Amer.,India, 1952. vol. 200, pp. 39-47; March, 1959.


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A Rocket for Manned Lunar