Rockets, Missiles, and Spacecraft of the National Air and Space Museum, Smithsonian Institution

Rockets, Missiles, and Spacecraft of the National Air and Space Museum, Smithsonian Institution
Author: Lynne C. Murphy
Pages: 138,901 Pages
Audio Length: 1 hr 55 min
Languages: en

Summary

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74. Orbital Workshop crew-quarters installations.

I
M131 chair control
Sleep compartment 70 sq ft
II
Head 30 sq ft
Wardroom 97 sq ft
III
M507 gravity substitute work bench
Experiment compartment 181 sq ft
M171 gas analyzer
M171 helmet stowage
ESS
IV
M092 LBNPD
Electric power control console
M131 rotating chair

The upper portion contains a large work-activity area, water-storage tanks, food freezers, film vaults, and experiment equipment.

The Airlock Module enabled spacesuited crew members to make excursions outside the Skylab to replace or adjust equipment, change film, or carry out other extra-vehicular activities.This capability was vital to emergency repairs by the astronauts on the first mission.The Airlock Module was attached to the OWS and passage to the module was accomplished through a hatch which connected the module to the interior of the workshop.When an astronaut entered the module, he would vent the atmosphere of the module into space.When the pressure in the airlock reached zero, the crew member could open the outer hatch and float out into space.

75. Airlock Module.

The Multiple Docking Adapter (MDA) was used by crews arriving or departing from the Skylab workshop.The Apollo command/service modules delivered crews to the MDA from which the astronauts could enter Skylab through the hatch in the docking port.In an emergency, two command/service modules could dock at the MDA.The MDA also held equipment for earth resources multispectral photography, materials processing, and astronomy.The Apollo Telescope Mount (ATM) was on top of and controlled by the MDA.It contained six astronomical instruments to obtain information about the Sun.

76. Multiple Docking Adapter.

Solar energy is the prime source of electric power on Skylab.Two systems of solar electric-cell arrays—one wing on the OWS and four panels on the ATM—deployed after the Skylab reached orbit.Principal contractors: OWS—McDonnell Douglas Astronautics Company; AM—McDonnell Douglas Astronautics Company; MDA—Martin Marietta Aerospace.


The Skylab components on display were presented to the museum by the National Aeronautics and Space Administration.

58

Apollo-Soyuz Test Project

77. Artist conception of the Apollo-Soyuz Test Project rendezvous.

On May 24, 1972, President Richard Nixon and Aleksey Kosygin, Chairman of the USSR Council of Ministers, signed an agreement “concerning cooperation in the exploration and use of outer space for peaceful purposes.”The signing represented a formal endorsement of negotiations that had been held between the two nations over several years.The agreement established the Apollo-Soyuz Test Project (ASTP) to develop and fly a standardized docking system “to enhance the safety of manned flight in space and to provide the opportunity for conducting joint scientific missions in the future.”

On July 15, 1975, the afternoon countdown for the Soviet launch was completed and Soyuz lifted off from the Baykonur complex near Tyuratum in Central Asia, some 3200 kilometers (2000 miles) southeast of Moscow. Soyuz carried cosmonauts Alexey Leonov and Valeriy Kubasov.

Taking advantage of Apollo’s larger fuel supply for maneuvering, Apollo followed Soyuz into orbit 7½ hours later. Apollo was launched atop a Saturn 1B from Kennedy Space Center, Florida.

After careful maneuvering, the two craft linked up around noon on July 18.Some 225 kilometers (140 miles) above Earth, the astronauts and cosmonauts visited each other’s craft, performed joint experiments, and made further tests of the new docking system.

Following the undocking Saturday, Apollo fired its engines briefly and moved away from Soyuz. Soyuz descended from orbit and landed in the south-central USSR early Monday morning, July 21.

Astronauts Stafford, Slayton, and Brand remained in orbit conducting research and making science demonstrations.Splashdown into the Pacific Ocean occurred in late afternoon on Thursday, July 24.

The historic ASTP mission was accomplished by using existing systems and a new docking module. The Apollo spacecraft was made available when the lunar-landing program was curtailed. Since the command module was built with a docking system designed to work only with U. S. spacecraft, a method of incorporating the new docking system had to be devised.

A second important problem was the difference between the spacecraft atmospheres. The Apollo used a pure oxygen atmosphere at about one-third of the atmospheric pressure on earth’s surface; Soyuz used a nitrogen-oxygen mixture at normal atmospheric pressure. To permit 59 crews to pass from Soyuz to Apollo without suffering from the “bends” (a painful condition experienced when nitrogen gas bubbles form in the body fluids), engineers had to design an airlock to equalize the pressure.

78. The Soviet Soyuz atop a three-stage launch vehicle lifts off July 15, 1975, to begin the joint US-USSR space mission.

79. Overhead view of Soyuz in orbit, photographed from the Apollo spacecraft during the joint mission. The three major components of the Soyuz are the spherical Orbital Module, the bell-shaped Descent Vehicle, and the cylindrical Instrument-Assembly Module from which two solar panels protrude.

80. View of Apollo spacecraft as seen in Earth-orbit from SoyuzThe Command/Service Module and Docking Module are contrasted against a black-sky background and the horizon of the Earth is below.

The docking module, 3 meters long and 1.5 meters in diameter (10 feet long and 5 feet in diameter), also solved the problem of incompatible docking mechanisms by carrying the new docking system on one end and a system compatible with Apollo on the other.

Prime contractor for Apollo Command Module, Service Module, and Docking Module was Rockwell International.


The Apollo hardware is from the National Aeronautics and Space Administration, and the Soyuz spacecraft is on loan from the USSR Academy of Sciences.

Apollo
Command module
Base diameter 3.90 m.(12.8 ft.)
Length 3.66 m.(12 ft.)
Weight 5896 kg.(13,000 lb.)
Service module
Diameter 3.9 m.(12.8 ft.)
Length 6.71 m.(22 ft.)
Weight at launch 24,947 kg.(55,000 lb.)
Docking module
Diameter 1.52 m.(5 ft.)
Length 3.05 m.(10 ft.)
Weight 1882 kg.(4155 lb.)
Soyuz
Orbital module
Diameter 2.29 m.(7.5 ft.)
Length 2.65 m.(8.7 ft.)
Weight 1224 kg.(2700 lb.)
Descent module
Diameter 2.29 m.(7.5 ft.)
Length 2.20 m.(7.2 ft.)
Weight 2802 kg.(6200 lb.)
Instrument module
Diameter 2.77 m.(9.75 ft.)
Length 2.29 m.(7.5 ft.)
Weight 2654 kg.(5850 lb.)
60

M2-F3 Lifting Body

81. Three chase planes salute the M2-F3 wingless lifting body following one of its rocket-powered flights. The blunt-nosed M2-F3 achieves its aerodynamic lift from the shape of its body.

This wingless craft is called a lifting body, because it derives its lift from the fuselage rather than from wings.Removing the wings reduces the weight of the craft, but adds significant control problems. The lifting body concept was developed early in the last decade to explore the problems of aerodynamic heating and vehicle control during reentry from earth orbit.These are the problems that will be especially critical in the space shuttle of the 1980s.

The M2-F3 tested flight behavior of wingless craft over a wide range of speeds.

The M2-F3’s forerunner, the M2-F2, made 16 flights—all unpowered—between July 1966 and May 1967.On May 10, it crashed on landing, partly due to control instability.The craft was rebuilt, and the center fin was added.This modification effectively solved the control problem, and the new craft, designated M2-F3, logged 27 more flights by December 1972.Some of the M2-F3’s flights were powered by a 3630-kilogram (8000-pound) thrust rocket which boosted the craft to a higher altitude.

The M2-F3 was launched from a B-52 bomber at a height of about 13,300 meters (45,000 feet) and a usual speed of 730 kilometers (450 miles) per hour.The maximum altitude achieved was 21,800 meters (71,500 feet).The M2-F3’s record speed was 1718 kilometers (1066 miles) per hour.The M2-F3 was built by Northrop.


The craft on exhibit is from the National Aeronautics and Space Administration.

Length 6.8 m.(22 ft., 2 in.)
Span 2.9 m.(9 ft., 7 in.)
Height 2.5 m.(8 ft., 10 in.)
Weight 2720 kg.(6000 lb.)empty; 4540 kg.(10,000 lb.)fueled
Speed 1718 km.per hr.(1066 m.per hr.)max.achieved
Altitude 21,800 m.(71,500 ft.)max.achieved
Mach number 1.5 max.achieved
61

Freedom 7

82. Marine helicopter hovers over Freedom 7 after the spacecraft carried the first American into space. Astronaut Shepard dangles in body harness as he is hoisted to helicopter.

On May 5, 1961, Alan B. Shepard, Jr., became the first American in space. He flew this Mercury spacecraft, Freedom 7, through a 15-minute, 22-second sub-orbital, or ballistic, space flight.

A Redstone booster, burning liquid oxygen and hydrazine-base fuel, lifted Freedom 7 from the launch pad at Cape Canaveral. The vehicle’s single engine developed 35,380 kilograms (78,000 pounds) of thrust.

The structure of the Mercury is titanium, covered with steel and beryllium shingles.The heat shield at the base of the spacecraft is of beryllium.

The heat shield served as a “heat sink” by storing the heat created by the spacecraft’s reentry into the earth’s atmosphere.The spacecraft reached the ocean before the heat could penetrate the interior of the craft.(Later flights used ablative heat shields, which protected the spacecraft by vaporizing and burning away during reentry.)

Freedom 7 traveled at a maximum speed of 8335 kilometers (5180 miles) per hour, going 485 kilometers (302 miles) downrange. The maximum altitude was 187 kilometers (116 miles).

Prime contractor for Mercury was the McDonnell Aircraft Company.


The Freedom 7 is from the National Aeronautics and Space Administration.

Diameter 2 m.(6 ft., 6 in.)max.
Length 2.8 m.(9 ft., 2 in.)at launch
Weight 1660 kg.(3650 lb.)at launch; 1100 kg.(2422 lb.)as exhibited
62

Gemini 7

83. This photo of Gemini 7 was taken through the hatch window of the Gemini 6 spacecraft during rendezvous maneuvers 260 kilometers (160 miles) above Earth.

Gemini 7 was launched on December 4, 1965, carrying astronauts Frank Borman and James Lovell, Jr., into a two-week flight. Gemini 6 and 7 accomplished the first manned rendezvous in space. It was an historic flight for the United States’ manned space program and an important step in the preparation for the Apollo lunar flights.

The story of the Gemini 7/6 mission had begun two months earlier. The October launch of Gemini 6 had to be delayed when Gemini 6’s Agena target vehicle failed to reach orbit. It was then decided that Gemini 6 would attempt to rendezvous with Gemini 7. Eight days after the launch of Gemini 7, Gemini 6 was ready. But once again, the launch had to be delayed—this time an electrical plug became detached from the Titan booster prematurely, shutting down the engines. Finally, on December 15, Gemini 6’s Titan II launch vehicle lifted off. Gemini 6 began a 6-hour chase to catch Gemini 7, which was in a near-circular orbit 300 kilometers (186 miles) high.

Gemini 6’s launch put it 1175 kilometers (730 miles) behind Gemini 7 in an orbit which varied from 161 to 272 kilometers (100 to 169 miles) in height. By flying in a lower altitude orbit, Gemini 6 astronauts Wally Schirra and Thomas Stafford circled the Earth at a higher velocity, slowing down as they moved to match speed with Gemini 7 at the higher orbit. Finally, Schirra jockeyed the Gemini 6 spacecraft to within 30 centimeters (1 foot) from Gemini 7

They stayed in formation for four revolutions while all four pilots practiced maneuvering. Then Gemini 6 broke off and reentered, splashing down on December 16, 1965.

Gemini 7 went on to complete its 14-day mission which set a record for the longest U. S. -manned space flight which stood until the first Skylab mission. Gemini 7 splashed down on December 18.

Prime contractor for Gemini was the McDonnell Aircraft Company.


Gemini 7 is from the National Aeronautics and Space Administration.

84. The Gemini spacecraft.

Rendezvous and Recovery Section
Ejection Seat
Adapter Equipment Section
Reaction Control System Section
Cabin
Retrograde Section
63

F-1 Engine

85. Thrust chambers of the F-1 rocket engine on the manufacturing line.

Five F-1 engines powered the first stage of the Saturn 5 launch vehicle that launched the manned Apollo spacecraft to the Moon.These engines developed a total thrust of 3.5 million kilograms (7.6 million pounds).They burn liquid oxygen and a form of kerosene at a rate of 13,475 liters (3560 gallons) per second.

The propellants are supplied to the thrust chambers by turbopumps driven by gas generators that use a fuel-rich mixture ratio of the same propellants used in the engine.

The F-l was developed and produced by Rocketdyne, a division of Rockwell International, under the technical direction of the National Aeronautics and Space Administration, Marshall Space Flight Center, Huntsville.Alabama.


The engine on exhibit is from the National Aeronautics and Space Administration.

Function Cluster of five providing 3.4 million kg.(7.5 million lb.)of thrust for Saturn 5 first stage
Thrust 690,000 kg.(1,522,000 lb.)
Propellants Kerosene (fuel) and liquid oxygen (oxidizer)
Length 5.8 m.(19 ft.)with nozzle extension
Diameter 3.8 m.(12 ft., 4.in.)with nozzle extension

86. The first Apollo/Saturn 5 space vehicle on its way to the launch pad.

64

Lunar Roving Vehicle

87. The Apollo 15 Lunar Roving Vehicle was the first motor vehicle on the Moon.

The Lunar Roving Vehicle (LRV) is a spacecraft designed to carry two astronauts, their life-support systems, scientific equipment, and lunar samples on the airless, low-gravity surface of the Moon.

Lunar Roving Vehicles were used on Apollo missions 15, 16, and 17 and were driven a total of 90 kilometers (56 miles) on the Moon.

The crew of Apollo 15, the first to use an LRV, drove their vehicle 27.9 kilometers (17.3 miles) at speeds up to 19-21 kilometers (12-13 miles) per hour. In comparison the Apollo 14 astronauts traveled only 4.2 kilometers (2.6 miles) on foot.

LRVs enabled the astronauts to carry heavy, bulky equipment and to place scientific instruments at considerable distances from the lunar module.

An LRV could carry two astronauts as far as 91.5 kilometers (57 miles) across the lunar surface or operate for up to 78 hours.

Each LRV was transported to the Moon in a compartment of the descent stage of a lunar module.

Four LRVs were built by the Boeing Company.Three were used on the Moon; the LRV on display was used in tests.


The LRV on exhibit is from the National Aeronautics and Space Administration.

Weight
On Earth 210 kg.(462 lb.)
On Moon 34 kg.(76 lb.)
Payload
On Earth 490 kg.(1080 lb.)
On Moon 80 kg.(178 lb.)
Length 3.1 m.(10 ft., 2 in.)
Width 1.8 m.(6 ft.)
Wheel base 2.3 m.(7 ft., 6 in.)
Turning radius 3 m.(10 ft.)
Drive One ¼ h.p.motor in each wheel; total 1 h.p.
Power source Two 36-v.silver-zinc batteries
65

Apollo Lunar Tools and Equipment

88. The Apollo Lunar Hand Tool Carrier holds 32 kilograms (70 pounds) of equipment, including a trenching tool, two geology scoops, four rock bags, a portable magnetometer, and five cameras.

Penetrometer
Tongs
Extension handle
Core tube caps assy.
Color chart & traverse map
Core tubes
16mm camera
Camera staff
35-bag dispenser
Core tubes
Scoop
Hammer
Lens/brush
Gnomon

Most tools and other pieces of equipment used by Apollo astronauts on the Moon were left behind as the astronauts departed to return to the Earth.This was done to conserve weight in the lunar module ascent stage so that the maximum quantity of samples of lunar soil and rocks could be brought back to the Earth.

Some tools and pieces of equipment, however, were returned to the Earth. These include such items as a lunar hammer, a 16-mm camera, film cassettes, lunar sample return containers, parts of a lunar roving vehicle fender, and parts of the unmanned spacecraft Surveyor 3 visited by Apollo 12 astronauts.

In addition, astronauts carried small mementos with them when they landed on the Moon.

Other lunar tools and instruments on exhibit were backup, prototype, or used by the astronauts in pre-flight training.


The lunar hammer is on loan from Alan L.Bean; other tools and instruments are from the National Aeronautics and Space Administration.

89. An Apollo lunar sample return container. In this view, the rock box contains sample material and core tubes.

66

Apollo Command Module: Skylab 4

90. Skylab 4 Command Module is hoisted aboard the U. S. S. New Orleans after completing 1214 orbits.

The Skylab 4 command module ferried the crew of the last Skylab mission—astronauts Gerald P. Carr, Edward G. Gibson, and William R. Pogue. The Skylab 4 crew lived in the Skylab for 84 days, from November 16, 1973, to February 8, 1974.

In flight, the Apollo command module operated with a service module—an equipment section, 7.4 meters (24 feet) long and 4 meters (13 feet) in diameter—attached to the command module.The service module provided electrical power, oxygen, and water for the command module for most of a typical flight.

In addition, the service module contained the 9300-kilogram (20,500-pound) thrust Service Propulsion System, an engine capable of being throttled and restarted.During Apollo lunar flights, the engine provided thrust for mid-course trajectory changes and boosted the command/service module combination out of lunar orbit and back to Earth.The service module was jettisoned just before reentry into the earth’s atmosphere.

During reentry, the command module’s exterior was subjected to temperatures of around 2800°C (5000°F).The command module is covered with an ablative heat shield composed of a phenolic epoxy resin in a fiberglass honeycomb structure.As friction with the earth’s atmosphere caused the heat shield to char and vaporize, the heat was carried away from the spacecraft.The heat shield varies in thickness from 7 centimeters (2.75 inches) at the base to .6 centimeter (.25 inch) at the forward section.Total weight of the heat shield is about 1400 kilograms (3000 pounds).

The prime contractor for the Apollo Command Module was North American Rockwell Corporation.


The command module is from the National Aeronautics and Space Administration.

Diameter 3.9 m.(12 ft., 10 in.)max.
Length 3.2 m.(10 ft., 7 in.)
67

Moon Rocks

91. A sample of vesicular basalt, produced by lunar volcanism 3.7 billion years ago, in the Lunar Receiving Laboratory. Devices record size and orientation of the rock. The cavities in this sample were formed by gases escaping from the still-molten rock. This sample is 13.5 centimeters (5.5 inches) long. A fragment of this lunar rock is on display in the “Apollo to the Moon” gallery.

During the six Apollo program moon landings, astronauts collected and returned to Earth samples of the lunar surface.The samples were collected both from the flat maria regions—great basins created by ancient meteoric impacts and later filled with lava from the moon’s interior—and from the highland regions.

Subsequent analysis of the samples has indicated that the moon’s surface is largely composed of three kinds of rock.

Basalt, the rock of the maria regions, was formed as lavas from the interior of the Moon welled to the surface, filled the great meteoric impact basins, and then cooled.

Anorthosite, the highland rock, is believed by many scientists to have formed when the original crust of the Moon cooled and solidified.According to this theory, a light mineral, plagioclase, floated to the surface of the Moon and formed the anorthosite.

Breccia, the shocked rock, is composed of large and small fragments of rocks which were shattered and redistributed on the lunar surface by meteoric impacts.Subsequently, the fragments were recombined into new rocks by heat and pressure.

Lunar soils are largely composed of fragments of the three types of rocks and their minerals, and glass produced by meteoric impacts and volcanic eruptions.


Lunar rock samples are on loan from the National Aeronautics and Space Administration.

92. Astronaut Schmitt collects samples with the lunar rake, a hand tool used to collect rocks and rock chips ranging in size from 1.3 centimeter (½ inch) to 2.5 centimeters (1 inch).

68

Suggested Reading

Historical and General Background
Clarke, Arthur C. The Promise of Space. New York: Harper & Row, 1968.
Dornberger, Walter. V-2. New York: Viking Press, 1954.
Durant III, Frederick C. ; and George S. James, eds. First Steps Towards Space (Smithsonian Annals of Flight, No. 10). Washington, D. C. : Smithsonian Institution Press, 1974. Available through the Superintendent of Documents, U. S. Government Printing Office, Washington, D. C. 20402 (stock no. 4705-00011).
Emme, Eugene, ed. The History of Rocket Technology. Detroit: Wayne State Press, 1964.
Ley, Willy. Rockets, Missiles, and Men in Space. New York: Viking Press, 1968.
Stoiko, Michael. Soviet Rocketry: Past, Present and Future. New York: Holt, Reinhart & Winston, 1970.
Von Braun, W. ; and F. I. Ordway. History of Rocket and Space Travel. New York: T. Y. Crowell, 1975.
Biographical
Lehman, Milton. This High Man. New York: Farrar, Straus & Giroux, 1963.
Thomas, Shirley, ed. Men of Space. 8 vols. Philadelphia: Chilton Book Co. , 1963.
Popular
Cortright, Edgar M. Exploring Space with a Camera. Washington, D. C. : U. S. Government Printing Office, 1968.
Davis, Merton; and Bruce C. Murray. View From Space: Photographic Exploration of the Planets. New York: Columbia University Press, 1971.
Gatland, Kenneth. Spacecraft and Boosters. Fallbrook, California: Aero Publications, 1964.
——. The Robot Explorers. New York: Macmillan, 1972.
Moore, Patrick. Space. London: Burke Publishing Co. , 1968.
Sharpe, Mitchell R. Living in Space. New York: Doubleday, 1969.
Technical
Corliss, William R. Space Probes and Planetary Exploration. Princeton, N. J. : Van Nostrand, 1965.
Glasstone, Samuel. Sourcebook on the Space Sciences. New York: D. Van Nostrand Co. , Inc. , 1965.
Purser, Paul E. ; Maxime A. Faget; and Norman F. Smith, eds. Manned Spacecraft. New York: Fairchild Publications, Inc. , 1964.
Ruppe, Harry O. Introduction to Astronautics. 2 vols. Campbell, California: Academy Press, 1966-1967.
Apollo Moon Landings
Collins, Michael. Carrying the Fire. New York: Farrar, Straus & Giroux, 1974.
Cortright, Edgar M. , ed. Apollo Expeditions to the Moon. Washington, D. C. : U. S. Government Printing Office, 1975 (stock no. 033-000-00630-6).
Lewis, Richard S. Appointment on the Moon. New York: Viking Press, 1969.
——. Voyages of Apollo. Chicago: Quadrangle Books, 1974.
Wilford, John N. We Reach the Moon. Rev. ed. Chicago: W. W. Norton & Co. , 1971.
Speculative
Sagan, Carl. The Cosmic Connection. New York: Doubleday, 1973.
Shkolvskii, I. S. ; and Carl Sagan. Intelligent Life in the Universe. New York: Holden-Day, 1966.
Strong. J. G. Flight to the Stars: An Inquiry into the Feasibility of Interstellar Flight. New York: Hart Publishing Co. , 1965.
Sullivan, Walter. We Are Not Alone: The Search for Intelligent Life on Other Worlds. New York: McGraw-Hill, 1964.
69

FIRST FLOOR PLAN

103 Vertical Flight
102 Air Transportation
101 Museum Shop
100 Milestones of Flight
115 Theater Entrance
114 Space Hall
113 Rocketry & Space Flight
105 General Aviation
106 Exhibition Flight
107 Life in the Universe
108 South Lobby
109 Flight Testing
110 Satellites
111 Benefits From Flight

SECOND FLOOR PLAN

203 Sea-Air Operations
201 Spacearium
215 Theater
213 Flight Technology
205 World War II Aviation
206 Balloons and Airships
207 Air Traffic Control
208 Special Exhibits
209 World War I Aviation
210 Apollo to the Moon
211 Flight and the Arts

Front Cover:

Lift-off of an Atlas Centaur carrying INTELSAT payload, August 23, 1973.

Earth from space photographed by the Apollo 16 crew.

Astronaut White performs first spacewalk from Gemini 4

Apollo 12 astronaut with United States flag on lunar surface.

Back Cover:

Main parachutes lower the Skylab 3 command module to the Pacific Ocean.

Solid rocket motors being jettisoned during launch of Geostationary Operational Environmental Satellite-1.

View from right-hand seat of Gemini 8 spacecraft when docked with Agena target vehicle.

Artist’s conception of Viking Mars lander as it heads for touch down.

Agena target vehicle seen from Gemini 11 after tether drop.

View of Skylab Orbital Workshop photographed by Skylab 2 crew.

Viking 2—bound for Mars—is launched aboard Titan Centaur on September 9, 1975.

Paul Calle’s interpretation of Saturn 5 launch.

New York to Norfolk composite photo from the Earth Resources Technology Satellite-1.

Photomicrograph of thin section of lunar rock.

Color enhancement of far ultraviolet photo of the Earth taken from space.

NASA’s Wallops Island Test Station in Virginia.

(All photographs from the National Aeronautics and Space Administration.)

Transcriber’s Notes

  • Retained publication information from the printed edition: this eBook is public-domain in the country of publication.
  • Silently corrected a few palpable typos.
  • Moved captions nearer the relevant images; tweaked image references within captions accordingly.
  • In the text versions only, text in italics is delimited by _underscores_.