During most of NASA's first 14 years, advanced research tasks, aeronautical and space, were assigned to the Office of Advanced Research and Technology (OART).* More than any other directorate of the civilian space agency, OART was patterned after the National Advisory Committee for Aeronautics (NACA), NASA's predecessor organization. Congress established NACA in 1915 to address the growing number of problems posed by the airplane. Five years later, the advisory body became a national research organization with its own aeronautical laboratory with purview for such research areas as aircraft power plants, aerodynamics, materials and structures, aircraft construction, and operating problems. The NACA also shared responsibility with the military services for guided missile and rocket research in the 1940s, and had grown to include four research centers when NASA was established in the fall of 1958.
The First Decade Reviewed
OART's programs were less visible and often harder to define and justify than those of the manned spaceflight and science and applications offices, but they were equally important. NASA was charged during its first decade with sending a man to the moon and returning him safely and exploring the near-earth and interplanetary environments, tasks that required great advances in technology. OART helped provide new electronic and computing equipment, attitude control devices, more comfortable and efficient life support systems, highly productive solar cells, and other pieces of hardware and processes without which NASA could not have accomplished its many goals.
OART's basic research program addressed four areas: fluid physics, electrophysics, materials, and applied mathematics. The space vehicle systems group  looked at advanced spacecraft design and structure, with special emphasis on reentry configurations and aerodynamics. NASA's popular lifting body program was conducted by the Space Vehicle Research Division, with flight-testing at the Flight Research Center in California. The Electronics and Control Division continually improved the onboard guidance and navigation systems carried by manned and unmanned spacecraft, data processing procedures, and communications and tracking systems. Scientists, medical doctors, and technicians concerned with human factor systems designed and tested life support equipment needed by astronauts and conducted experiments on advanced man-vehicle systems. Electric, chemical, and nuclear propulsion also were subjects tackled by OART personnel.
Aeronautics research received the biggest share of OART's attention and budget during the 1960s, and a trend toward greater participation in aeronautics was building late in the decade. Although most of NASA's energies were delegated to space projects during the first decade, aeronautics teams were assigned to conduct or oversee applied research in every regime of flight, from hovering to supersonic, including the well-publicized X-15 project. General aviation needs were also addressed by OART.
Aeronautics and Space Technology, 1969-1978
Advanced research needs during the early years of NASA' second decade were met as they had been during the first 10 years. But a 1972 reorganization and increasing attention to basic and applied aeronautical research drastically changed the flavor of the agency's research program. Formally, the new Office of Aeronautics and Space Technology (OAST) was designed to serve national needs by building a research and technology base, conducting systems and design studies, and carrying out systems and experimental programs. Its work fell into the following categories: air transportation system improvement, spacecraft subsystem improvement, providing technical support to the military, and applications of technology to nonaerospace systems. 1
Specifically, OAST and its contractors worked on such projects as reducing aircraft noise and airport congestion, short takeoff and landing aircraft crosswind landings, vertical takeoff and landing aircraft auto landing systems, aircraft ride quality, aircraft safety, fire safety technology, advanced supersonic aircraft technology, optical mass memory systems, laser communications, new solar energy systems, Space Shuttle support, and atmospheric entry designs. This list is just a sampling; OAST was flexible and changed its goals as directed by NASA management, Congress, the military services, and industry.
Managing the Aeronautics and Space Technology Program
From 1969 through 1978, OART/OAST had nine different associate administrators, either acting or permanently assigned, leading the program's activities. Each brought his own management style and changes. Table 5-1 tracks the Office of Advanced Research and Technology and the Office of Aeronautics and Space Technology through four distinct phases of management.
 James M. Beggs, who had become the associate administrator for OART in 1968, left NASA in early 1969 to become Under Secretary of Transportation. Bruce T. Lundin and Oran W. Nicks took turns as acting heads of the office until Roy P. Jackson was appointed in November 1970. Jackson rejoined Northrop Corporation in late 1973. Edwin C. Kilgore and Bruce K. Holloway served as temporary leaders until Alan M. Lovelace was assigned the job in August 1974. Lovelace became Deputy Director of the agency in 1976, leaving the research post vacant again. Robert E. Smylie acted in the position until December 1976, when James J. Kramer was assigned as associate administrator for OAST, first as acting, then permanently in October 1977. The associate administrators were assisted by a revolving cast of deputies, special assistants, and division directors (see table 5-1 for details).
It was NASA's policy to conduct a great amount of its work through contractors, whose work was directed, monitored, and augmented by an in-house staff. Research centers that contributed primarily to the agency's research and aeronautics program included the Flight Research Center (aeronautics flight testing) in California, Ames Research Center (life sciences, aeronautics) in California, Langley Research Center (aeronautics) in Virginia, and the Lewis Research Center (propulsion) in Ohio.
The Office of Advanced Research and Technology/Office of Aeronautics and Space Technology routinely received from 7 to 11% of NASA's total research and development budget, with the bulk of the funds going to manned spaceflight and space science and applications programs. OART/OAST's projects were smaller, were often conducted under the joint auspices of another government agency, and were sometimes short-term; they usually did not require expensive flight tests. OART/OAST products often hitched a test ride on manned and scientific payloads.
Because of the changing management of OART/OAST and its evolving goals, it is not possible to trace the funding for individual projects over the 10-year period as done in the other chapters. Instead, the following budget charts present funding data for each year. Selected projects are reported on individually. For more detailed information, consult the NASA annual budget estimates. However, the user should not expect to find the budget categories to be similar from year to year or to be broken down into smaller project fields.
During NASA's first decade and until a 1970 reorganization of the Office of Advanced Research and Technology, basic research was included as one of its major divisions. Basic research was defined as fundamental investigations of the physical and mathematical laws that governed NASA's flights. Findings did not have to have a specific application to any ongoing projects, but instead contributed to the general pool of scientific knowledge in the subject area. The term "basic" was dropped in  1970 and OART/OAST's research tasks became increasingly applicable to approved agency projects.
Hermann H. Kurzweg, appointed director of research in 1961, was active in that position until 1970, when he was named chief scientist for OAST. The chief scientist position was dropped in early 1974. In the 1970 reorganization, George C. Deutsch became director of a Materials and Structures Division, materials and structures having previously been part of the basic research program. A Research Division was added to OAST again in 1973, with Carl Schwenk serving as its director through 1977. In 1978, the office was renamed research and technology, and Deutsch was appointed director.
The basic research program was divided into four sections: fluid dynamics, electro physics, materials, and applied mathematics. As noted above, materials and structures became increasingly important as an applied research field during the 1970s. Research also continued in the other areas, albeit at a less visible level. The research program was never generously funded, but it was supported by all NASA's research centers and a great many contractors.
Fluid dynamics. Specialists working in this field sought to better understand the different flow processes of liquid and gas mixtures involved in aircraft, spacecraft, and propulsion system operation. NASA was especially interested in the dynamics of entry into an atmosphere.
Among the many investigations under way in the 1970s, the following are typical: gas dynamic laser research, sonic boom research, fluid dynamics of the interaction and dispersion of atmospheric pollution, and skin-friction balance for measurements of the skin friction of supersonic aircraft structures. Progress was also made on resolving some of the confusion and scatter that existed in wind tunnel measurements of the location and extent of the transition of the viscous boundary layer from laminar to turbulent.
In 1974, NASA attempted to launch a Space Plasma High Voltage Interaction Experiment (Sphinx) into an elliptical orbit to investigate the effect of charged particles on high-voltage solar cells, insulators, and conductors. Sphinx was an auxiliary payload, to be launched with a Viking spacecraft model by a Titan IIIE-Centaur. Because of a launch vehicle failure, the vehicles were destroyed by the range safety officer eight minutes after launch.
Electrophysics. This special branch of physics is devoted to investigating the macroscopic and atomic electric behavior of solids, liquids, and magnetic force fields. Among other things, NASA specialists assigned to this field during the 1970s worked on a technique for continuously tuning a laser over many wavelengths. Such a technique was needed to develop a laser for use in electronic communication systems. In another task, tests were conducted to develop techniques for avoiding voltage breakdown in radio frequency transmission lines and antennas.
Applied mathematics. Mathematicians working for NASA investigated a class of stochastic optimal control problems to learn more about exact solutions of nonlinear stochastic differential equations. Performance criteria included minimum time, minimum expected fuel consumption, and least upper bound fuel consumption. The results were applicable to calculations relating to the control of vehicles by low-thrust engines.
Materials and structures. The aim of materials and structures research is to provide increased payload capability as a result of structural weight reductions and low-cost  energy conservation systems. Specific assignments included the following: developing a new technique for obtaining more processable higher-temperature-resistant polymers for use as matrix materials in advanced resin fiber composites; finding a seal that can maintain close separation without solid-to-solid rubbing; designing a feedback-controlled heat pipe and a thermal diode heat pipe that permit heat transfer in only one direction (tested aboard ATS-6; improving thermal protection for manned reentry vehicles; developing new composite materials over wrapped on metal liners for use in pressure vessels; inventing graphite-polyamide structures for use in advanced space vehicles; and developing an iron-based alloy for use in cryogenic fuel tanks.
In 1970, NASA released for public use its computer program for structural analysis (NASTRAN). It was used in the design and analysis of various types of aeronautical and space vehicle structures and in the design of other structures such as railroad roadbeds and tracks, nuclear reactors, and skyscrapers. With NASTRAN, engineers could conduct complete thermal analyses as well as predict aircraft flutter.
Space Vehicle Systems
The Space Vehicle Systems Division within OART/OAST was concerned with problems vehicles might encounter during launch, ascent through the atmosphere, space flight, and atmospheric entry. During NASA's second decade, this group conducted two major aero thermodynamic research projects: lifting body research and planetary entry research.
Milton B. Ames, an old NACA hand, was director of the Space Vehicle Division from 1961 until the 1970 reorganization. The 1970 roster listed Frederick J. DeMeritte as director of the lifting body/entry technology program until 1973, when the division was dropped. It reappears in 1975 as the Aerodynamics and Vehicle Systems Division, led by James J. Kramer. William S. Aiken, Jr., assumed the post in 1976, when Kramer became acting associate administrator. In 1978, Aiken was acting director of the Aeronautical Systems Division.
Lifting bodies. Lifting bodies, wingless vehicles that obtain aerodynamic lift from their shape alone, were the subject of serious research at NASA from the early 1960s through 1975. This configuration was one of three that was studied in the original search in the 1950s for a suitable spacecraft design, and many specialists at NASA's Ames and Langley Research Centers believed that the glider concept would have merit for a later-generation vehicle. During NASA's first 10 years, Langley and Ames sponsored wind tunnel research and flight-testing on a variety of lifting body designs.
Two lifting bodies were flight tested at NASA's Flight Research Center in the California Mojave Desert during the 1960s. Both were built by Norair Division of Northrop Corporation. Ames Research Center personnel favored a flattop round-bottomed vehicle with a blunt nose and vertical tail fins called the M2-F1/2. Langley designed a round-top flat-bottomed vehicle, also with a blunt nose and three vertical tail fins, designated the HL-10 (see table 5-12). Both were designed to be released in midair from under the wing of a B-52, from which they could glide to a desert landing strip or conduct a powered test flight. Made of aluminum, they weighed less than 2500 kilograms and could accommodate one pilot.
 The M2-F2, first flown in 1966, was damaged during a crash landing during its 16th flight. The HL-10's maiden flight also took place in 1966. Two years later an XLR-11 engine was installed to give it the capability of powered flight. Under the terms of a joint agreement, both NASA and Air Force pilots tested the lifting bodies at the Flight Research Center, which shared facilities with Edwards Air Force Base. Additionally, the Air Force had its own lifting body design, the X-24 built by the Martin Company, which NASA pilots would help evaluate.
Lifting body test flights became almost routine during the early 1970s. The M2-F2 was rebuilt as the M2-F3 (see table 5-13). Northrop added a center vertical fin and installed an XLR-11 engine. Flown for the first time in June 1970, it was tested 27 times before it was retired in December 1972. It reached supersonic speeds for the first time in August 1971 and later flew at a top speed of Mach 1.6.
Pilots flew the HL-10 for a total of 37 flights and simulated Space Shuttle-type approach and landings. The HL-10 reached a maximum speed of Mach 1.86 and an altitude of 27 524 meters. Its last flight was in July 1970.
Martin completed the X-24A in July 1967, and NASA and the Air Force spent until early 1969 conducting wind tunnel and captive flight tests with it (see table 5-14). It took its first glide flight in April 1969; it was flown powered the following September. The Air Force's lifting body was a half-cone (flat top and round bottom) with three vertical tail fins. Like the others it was equipped with an XLR-11 engine and weighed 2850 kilograms. It was flown 28 times. A fire in the engine section caused minor damage in August 1970, and the Air Force sent it back to Martin for external modifications. A fore body was added to the nose, and the planform was changed into a double-delta configuration. The 6250-kilogram X-24B flat iron had higher lift/drag characteristics, which increased its flexibility as a test vehicle (see table 5-15). The planform also was representative of configurations being investigated for future hypersonic aircraft. Pilots tested the X-24B 36 times from August 1973 through November 1975. Its fastest speed was Mach 1.76, its maximum altitude 22 580 meters. The very last lifting body flight conducted by NASA was with the X-24B: the 144th flight on November 26, 1975. NASA had decided that it had obtained all the useful flight data on transonic and hypersonic flight that could be had from the three lifting body types and terminated its program (see table 5-16 for a log of flights). Much of the data would prove valuable in the design of the reuseable Space Shuttle.
The Air Force continued to pursue more advanced lifting body designs. NASA had originally agreed to contribute to an X-24C hypersonic (Mach 6) flight testing program, but had to terminate its support in 1978 for budgetary reasons (see table 5-17 for more information on the development of the X-24).
Planetary entry. NASA had approval to send two instrumented landers to the planet Mars in 1976 and needed an entry and landing system to ensure the vehicles a soft touchdown. Over five years, OAST's space vehicle systems group conducted a variety of flight and wind tunnel tests of large parachutes designed for the Viking landers. The specialists were concerned with obtaining more stable operation at high speeds and with the very low density and pressure conditions of the Martian atmosphere. The type of chute chosen was the disc-gap-band parachute.
In a related area of research, OAST tested an inflatable device designed to be attached to the aft end of a planetary entry vehicle to provide even greater deceleration. OAST also developed a computing program to determine the heating rates of spacecraft during planetary entry.
On June 20, 1971, OAST conducted a Planetary Atmosphere Experiments Test at Wallops Station, Virginia, using a Scout booster. The test demonstrated that it was possible to obtain density, pressure, and temperature data from a probe vehicle entering the atmosphere at a high speed (see table 5-18).
In 1974, an Advanced Atmosphere Entry Technology program was initiated to  establish a base of information to permit the design of probes that could safely land on the outer planets. Included in the program were methods for estimating entry heating.
Guidance, Control, and Information Technology
Recognizing the importance of electronics to the development and reliable operation of spacecraft, NASA worked to build an expertise in this field during the 1960s. When the Office of Advanced Research and Technology was first established in late 1961, a division of electronics and control was included in its organization. In addition to expanding electronics activities at the-agency's existing centers and among its contractors, NASA established an Electronics Research Center (ERC) near Cambridge, Massachusetts, in 1964. ERC was responsible for guidance and control, instrumentation and data processing, communications, and electromagnetic research.
During the budget-cutting years after the successful Apollo lunar landing, NASA was forced by Congress to close ERC in 1970. NASA Administrator Thomas O. Paine admitted that the agency "could not afford to continue to invest broadly in electronics research."2 On June 30, the facility was transferred to the Department of Transportation as the Transportation Systems Center. Electronics research in support of space and aeronautics projects would again be assigned to the remaining NASA centers and to its contractors. During NASA's second decade, efforts were directed at improving the operational characteristics and data handling efficiency of a great number of electronics systems, while reducing their size, weight, cost, and power requirements. By 1978, NASA's official goal was to develop "a technology base that would enable a 1000-times increase in flow of space-derived information at one-tenth the cost of mission operations."3 Following is a sampling of projects conducted during the 1970s.
At the Ames Research Center, specialists, working from flight test records and digital computers, developed a new procedure for mathematically modeling  airframes, vehicle control systems, and pilot dynamics. This procedure made possible more accurate predictions of vehicle and pilot performance before flight.
Ames, the Marshall Space Flight Center, and the Manned Spacecraft Center worked together to develop a backup manual guidance and control system for the Saturn V launch vehicle. This system gave Apollo astronauts the added capability of injecting into earth orbit for some failures of the automatic guidance and control system rather than aborting the mission.
Before ERC closed, personnel there completed an operational model of a scanning electron mirror microscope. The instrument was built to examine semiconductor devices, particularly integrated circuits that do not have multilevel flat surfaces.
ERC also developed a technique for more cost-effective programming of small computers. Called a time-shared disc operating system, it allowed the computer to participate in program development by continuous interaction with the user.
NASA also was involved in the development of a pilot warning collision threat indicator that would be acceptable to the general aviation industry. Specialists at Ames worked to optimize operating frequencies, size, and weight, thereby reducing its cost. A first round of flight tests of the hardware took place in the early 1970s. Ames was also involved in enhancing the safety and utility of general aviation aircraft by designing a new split-surface control system and an inexpensive flight director display system.
Goddard Space Flight Center was assigned the task of overseeing research in optical methods for data processing. Scientists applied lasers and coherent optics to the problems of handling large amounts of experiment data from spacecraft.
At Langley, an improved landing radar for vertical and short takeoff and landing (V/STOL) aircraft was tested. This device proved excellent for measuring range and range rate at low altitudes. In 1972, a totally automatic landing system was demonstrated by a CH-46 helicopter.
The Jet Propulsion Laboratory, which is charged with the agency's deep space exploration program, worked on a large dish-type antenna that could be stowed folded during launch. The antenna was composed of a single curved surface. Specialists believed that an antenna as large as 17 meters was possible. JPL also readied a dual frequency (S-X band) experiment that was flown on Mariner 10, which was launched in November 1973.
Together, Ames and Goddard produced telemetry coding techniques that improved information transmission rate and error reduction for spacecraft communications channels. A laboratory prototype was built in 1970.
Also at Goddard, a team developed microcircuit techniques during the early 1970s that were applicable to the design of low-power high-performance miniaturized spacecraft computing systems.
In 1970, Goddard conducted its first balloon experiments to measure the effect of the atmosphere on laser beams. A detector package was carried aloft by the balloon, and two lasers on the ground operated at wavelengths of 10.6 and 0.5 microns. Marshall Space Flight Center in 1973 conducted laser communication tests using high-altitude aircraft.
Marshall developed and tested an inertial laser gyro for use on a three-axis strap down system. Digital gyro data were sent directly to a computer to determine the rate and position of the vehicle. Langley, also working on control gyro research,  designed a high-response variable-momentum control moment gyro. It could be applied to spacecraft control systems and had twice the momentum storage capacity of a similar device carried on Skylab.
The first flight of an aircraft in which the control surfaces were moved through electronic signal inputs and digital computers with no mechanical reversion capability was made at Flight Research Center in 1972.
A CV 990 aircraft was used by Ames in 1972 to test its program to evaluate power-off automatic landings like those the reusable Space Shuttle would make in the 1980s. The auto land system provided terminal area energy management and landing guidance. Tests indicated that unpowered automatic landings would be possible with existing ground navigation aids. In another Shuttle-related research project, Langley worked to design the craft's antenna systems. Specialists were concerned with how to protect the antennas against thermal and structural stress. Langley also developed a medium-power microwave traveling wave tube for the Shuttle.
For the joint U.S.-Canadian Communications Technology Satellite, launched in 1976, OAST improved the efficiency of microwave power-amplifier tubes from 10-20% efficiency to more than 50%.
In 1975, NASA research staff demonstrated the ability of a breadboard model of an all-solid-state star tracker (STELLAR) to track automatically multiple stars in a single field of view.
Frank J. Sullivan was the director of OART/OAST's electronics program from 1965 until 1974, when Peter R. Kurzhals took over as leader of the Guidance, Control and Information Systems Division. Still under Kurzhals' direction, the office was renamed the Electronics Division in 1977, only to become the Space Systems Division the next year.
Human Factor Systems
Life sciences activities at NASA were spread among three directorates: Office of Space Science, Office of Manned Space Flight (later Office of Space Flight and then Office of Space Transportation Systems), and OART/OAST. This continued a tradition begun during the 1960s. The research directorate had responsibility for the human factor systems program, in which it was held that man was a critical component of the spacecraft system, or part of a man-machine system.
Human factor specialists were concerned with the interfaces between pilot/astronaut and his craft that influenced his health, comfort, survival, and decision-making skills. Life support systems, protective garments, information displays, and spacecraft controls were all under the purview of this group. A related area of interest was understanding the physical and psychological reactions of man to long exposures to the space environment. Although a critical program, the human factor systems effort was not highly visible, and funding levels were always low. There were no major flight projects devoted solely to human factors research, although each manned space flight and the many series of aircraft test flights returned data of interest to the specialists. The following are examples of the kinds of projects undertaken by OAST in the field of human factor systems research.
NASA, along with the National Academy of Sciences, sought to determine the  cause for a type of motion sickness experienced by several Apollo astronauts. OART/OAST researchers developed several instruments that could be used to measure various physiological activity during flight, including an electro-optical instrument to measure the blood oxygen level and a device to measure respiratory gas flow volume digitally.
A reverse osmosis water reclamation unit using glass membranes was developed under the auspices of OART/OAST at Ames Research Center. And the Manned Spacecraft Center supported research to fabricate a prototype emergency life support system, which included a breathing vest, a gas-operated pump for air and coolant circulation, and a sublimator unit for cooling. MSC was also working on a constant-volume metal fabric spacesuit of only one layer.
Looking ahead to life aboard a permanent space station, doctors and technicians were interested in observing the results of extended confinement on human subjects. During Tektite I and II, conducted in 1969 and 1970, Navy, NASA, and Department of the Interior marine scientists and biomedical and behavioral researchers collected information on group interactions, psychomotor performance, and habitability. During the first experiment, four scientists spent 60 days in a nitrogen-oxygen environment at a depth of 13 meters in the Caribbean Sea. Several teams of scientists were observed in the second underwater environment experiment, also for 60 days. The subjects' responses to their artificial environment provided data useful in predicting crew behavior and in designing a space station habitat.
In related projects, MSC took a survey among its astronauts and among Air Force pilots to determine their preference for off-duty activities during a long-duration flight. MSC also began the development of flexible boots and other garments that would make a long flight more comfortable. At Langley Research Center, researchers designed shelters for crews stationed on the moon for long periods of time.
OART/OAST sponsored one small flight project during the second decade: the Orbiting Frog Otolith Experiment (OFO). Two bullfrogs were observed during a seven-day orbital flight in 1970 to gain information on the adaptability of the vestibule in the inner ear to sustained weightlessness and acceleration (see table 5-19).
Ames Research Center assisted the Department of Defense during the early 1970s by designing a liquid-cooled helmet for Army helicopter pilots. Pilots operating in the jungles of Southeast Asia were subjected to such severe heat that their bodies could not maintain a normal temperature. As it was impractical to cool the entire cockpit, the NASA-designed helmet liner was used to improve the pilots' comfort and heat balance.
Walton L. Jones was director of OART/OAST's Biotechnology and Human Research Division from 1964 through 1970. In 1971, the division was retitled aeronautical life sciences, and in 1973 it carried the name Aeronautical Man-Vehicle Technology Division. Leo Fox assumed the directorship in 1971, followed by Gene E. Lyman in 1972. Lyman served as director of the Aeronautical Man-Vehicle Systems Division through 1977. The 1978 management roster carried no biotechnology slot.
Space Power and Propulsion Systems
During the 1960s, NASA continually improved the dependability and efficiency of its family of chemical propulsion launch vehicles. But advanced researchers were looking ahead to the demands of future decades and to new sources of propulsion and onboard power. Permanent orbital space stations and interplanetary spacecraft traveling far from the sun would have special requirements.
Three propulsion sources were available: chemical, electric, and nuclear. NASA had had a great deal of experience in improving chemical systems during its first decade of operations, but researchers sought during the 1970s for lighter-weight, ever more efficient systems. Electric propulsion could be put to work in zero gravity in combination with traditional chemical or nuclear vehicles. Nuclear propulsion had been the subject of much study by NASA and the Atomic Energy Commission (AEC) since 1960. The space agency had agreed to take a major responsibility in the development of a nuclear launch capability and had spent considerable funds during the 1960s developing and testing supporting hardware.
Batteries and solar cells have provided spacecraft with onboard power since the beginning of the space program, and OART/OAST worked through two decades improving this system. Battery size and weight were reduced and solar cells given longer lives and greater efficiency. Nuclear sources for spacecraft power-radioisotope generators and reactors-were studied and tested.
Lewis Research Center continued to be the lead center for advanced propulsion and power systems research during the 1970s. Large-budget projects were not approved; even so, systematic, but slow, progress on a great variety of propulsion-power sources was made.
Adelbert O. Tischler directed OART/OAST's chemical propulsion research from 1963 through 1969. Milton Klein managed the AEC-NASA Space Nuclear Propulsion Office for NASA. William H. Woodward was assigned management authority over power and electric propulsion. In the 1970 reorganization, oversight of chemical and electric propulsion and power research was combined into one office, the Space Propulsion and Power Division, under Woodward. Nuclear research remained under the purview of Klein in the Space Nuclear Systems Office. He was succeeded by David S. Gabriel in 1972; the office was dropped the following year. James Lazar replaced Woodard in 1975 and remained in that position through the rest of the second decade.
 Chemical propulsion. During the 1960s, the most visible chemical propulsion projects being conducted by NASA were the large solid rocket motor and the M-1 liquid propellant engine, the so-called "million-pound thrust engine." Both of these projects progressed to the hardware development and testing point when a shortage of funds and lack of clear need for the big motors led to their postponement and cancellation late in the decade.
During the 1970s, NASA concentrated on less expensive chemical propulsion projects, most of which were aimed at improving currently available products or processes. Progress was made, for example, in developing a chemical process to manufacture oxygen difluoride more inexpensively. Researchers looked at a floxmethane space storable combination. And tests were conducted with gaseous oxygen and gaseous hydrogen for possible use as an auxiliary propellant.
On the solid propellant side, a series of solid motor prototypes were successfully tested during the decade in the search for a high-efficiency motor. Among their features were lightweight all-carbon nozzles and expansion cones, special igniters that provided a several-second thrust buildup to minimize shock to the spacecraft, and flexible propellants. A low-acceleration motor was also designed and tested. A high energy restartable motor that could deliver 10% more energy was tested during the early 1970s. A new sounding rocket, the Astrobee F, required OAST's assistance with the development of its dual thrust system.
OART/OAST also settled down to solving Shuttle main engine design problems. Technology efforts were directed toward improving turbomachinery and accurately calculating combined chamber and nozzle performance. Shuttle's auxiliary propulsion system demanded OAST's attention, as well, as tests proved the superiority of a high-pressure gaseous oxygen-gaseous hydrogen system.
For interplanetary spacecraft, OAST designed a hydrazine monopropellant attitude control system. The program also demonstrated the need for pump-fed engines for large planetary orbiters and landers.
Another major goal of the chemical propulsion researchers was to discover new energy storage concepts capable of more than doubling the specific impulse of current chemical rockets. They evaluated atomic hydrogen for this project with some encouraging results.
Electric propulsion. Electric propulsion provides relatively low-powered thrust for use in zero gravity. Once in orbit, electric propulsion systems can boost a payload into a different orbit or be used during orbital stationkeeping or docking maneuvers. Electric power generated by a solar or nuclear device is fed to a thruster system, which can be electrothermal, electrostatic, or electromagnetic. In addition to laboratory tests, NASA conducted several flight experiments during the 1960s and 1970s to evaluate candidate electric propulsion systems.
Project SERT (Space Electric Rocket Test) was initiated in the early 1960s, with the first ballistic test flight of an electric rocket being accomplished in 1964. The test proved out the Lewis Research Center electron bombardment design (cesium thruster). Official approval of an orbital test was given in 1966, but the launch was postponed until 1970. SERT 2 was to have demonstrated the long-term operation of electric thrusters, but electrical shorts in the high-voltage system caused the thrusters to fall short of their expected six months lifetime (see table 5-20).
In 1971, test of the first breadboard model of a fully automatic electric propulsion....
....system for an interplanetary spacecraft commenced. Such a system, which would rely on solar energy, would be used on an interplanetary flight mission.
An auxiliary electric propulsion engine was tested onboard ATS 6, launched in 1974 and used successfully for many years. The ion thruster engine was designed for the difficult north-south station keeping requirements of the satellite. By the end of the decade, NASA had made substantial progress in the development of ion thrusters for both low-energy applications and higher energy levels for primary propulsion systems.
Nuclear propulsion. NASA's interest in nuclear propulsion dates to the early 1960s, when the agency recognized that it should investigate how the products of atomic research would affect space power and propulsion systems. With the Atomic Energy Commission, NASA formed a joint Space Nuclear Propulsion Office, from which the space agency could monitor and evaluate any new applicable technology developed by the AED. Powerful boosters and onboard spacecraft power systems were among the products NASA had in mind.
NASA's first joint venture with AEC included testing AEC's Kiwi family of reactors. For nuclear rocket development, NASA assumed responsibility for the nonreactor components, for combining the reactor and other hardware into engine systems, for vehicle development, and for providing the necessary propellants. Reactor testing was to be followed by the development of a prototype vehicle in 1964 and a flight vehicle in 1965. The first contract for a 75 000-pound-thrust Nuclear Engine for Rocket Applications (NERVA), of which the reactor would be one element, was let in 1961. Numerous problems with hardware development and testing led to a postponement of the schedule. NERVA required expensive test stands and a long lead time to solve the many new problems associated with the technology, and it did so at a time when Congress was looking for projects to pare from NASA's budget. But the agency's nuclear program survived into the second decade, with a new-generation reactor, Phoebus, being tested during the summer of 1968 and NERVA test engines being assembled for evaluation in 1969. However, it did not flourish.
 During 1969, NASA conducted NERVA tests from March through August, with 28 successful engine startups. The engine operated for a total of 2.8 hours, including 3.5 minutes at full thrust (55 000 pounds). The next year saw the preliminary design of the NERVA flight engine, with a preliminary design review being initiated in October. Studies called for reusable stages, 11 meters in diameter. In 1971, the engine baseline design was completed and engine component detailed design was initiated. Fiscal year 1972 funding restrictions allowed NASA to support only selected critical engine hardware development; other aspects of the program were put on hold. In 1972, NERVA was officially cancelled. NASA's space nuclear program was reduced to investigating ways to use atomic energy on a much smaller scale than NERVA. The next year, the joint NASA-AEC Space Nuclear Systems Office was abolished since there were no plans to use a nuclear rocket during the next 10 to 15 years. NASA's interest turned to using atomic energy for auxiliary onboard power systems.
Electric power. Designers could tap three sources for onboard spacecraft power: chemical, solar, and nuclear. Batteries, the chemical source, used alone can provide power for only a short time. Teamed with solar cells, they are a reliable source. The chemical-solar combination was used successfully throughout the 1960s, often tailor-made for the specific mission's needs. By the end of the first decade, this kind of system could be depended on for up to 1000 watts of electrical power. But spacecraft of the 1970s and 1980s would require megawatts of electricity for operating direct broadcast satellites or providing a crew bound for Mars enough power for their life support system. OART/OAST was tasked with finding either a much-improved solar-chemical system or a nuclear system or a combination of some kind. Two kinds of nuclear power sources were available: radioisotope generators (RTG) and reactors. The AEC-NASA partnership in place during the 1960s and early 1970s for the development of a nuclear rocket was extended to investigate nuclear power sources.
AEC had begun its Systems for Nuclear Auxiliary Power (SNAP) program in the 1950s; NASA showed interest in SNAP in the early 1960s. It chose SNAP-8, a reactor system, for future spacecraft applications and SNAP- 11, an RTG, for a Surveyor orbiting lunar vehicle. With the cancellation of the Surveyor orbiter, NASA turned to AEC for an RTG for the Nimbus meteorological satellite. SNAP-19, onboard Nimbus B, sank to the bottom of the ocean along with chunks of the spacecraft after a launch vehicle failure. Another SNAP-19 proved successful onboard Nimbus 3 in 1969. An RTG was also installed and used on the Viking Mars spacecraft, which landed in 1976. SNAP-27, an RTG, was used to power the Apollo lunar surface experiment package placed on the moon by the crew of Apollo 12. Pioneer probes bound for the outer satellites would also carry RTGs.
NASA continued to test reactor-type SNAPs as well. In 1971, the 2-10 Kw Brayton turbo generator being tested by the agency passed 8000 hours of operation. A contract was let for the development of a 15-80 Kw unit. In 1975, a 2000-10 000 watt Brayton turbine power system completed more than 20 000 hours of testing.
Although considerable attention was being given nuclear power sources, NASA did not ignore chemical-solar systems. Solar cells were improved (1977 goals called for solar cells five times thinner and lighter than those in use at the time) and nongassing lightweight nickel-cadmium batteries were evaluated. Specifications were written for primary batteries with a shelf life of 5 to 10 years for outer planet atmospheric entry probes.
The Office of Advanced Research and Technology was reorganized in 1970 to "provide increasing emphasis on improving aeronautical research."4 From one OART division, aeronautics expanded to three: aeronautical operating systems, aeronautical research, and aeronautical propulsion, with special offices devoted to STOL and experimental transport aircraft. NASA was starting to answer its critics who had been accusing the space agency of ignoring the traditional role it had inherited from NACA of leading this country's aeronautical research program. Those critics, which included the Senate Committee on Aeronautics, were concerned with the health of general and military aviation, challenges from overseas manufacturers of aircraft in the international marketplace, and the United States' place as a technological leader.5 The Committee questioned the adequacy of the nation's aeronautics policy and urged NASA to support aeronautics more staunchly than it had during the 1960s when it had been preoccupied with landing a man on the moon.
In 1969, the Aeronautics Division held itself responsible for the advancement of subsonic, supersonic, and hypersonic flight, as well as flight safety, jet noise, sonic booms, cockpit instrumentation, aircraft handling qualities, and the operating environment. This list of concerns would grow rapidly over the next 10 years.
The 1972 change in the advanced research directorate's name, from the Office of Advanced Research and Technology to the Office of Aeronautics and Space Technology, was more than a symbolic gesture. It put aeronautics at the associate administrator's level at NASA Headquarters. In 1972, NASA increased its professional staff working on aeronautics projects by 7%, while reducing the total staff by 3%. According to Roy P. Johnson, Associate Administrator for OAST, "We now have 20 percent of our NASA people resource working on aeronautics technology.6 Budgets for aeronautics were also increasing. And the agency was taking on new roles: "Our goal in NASA is to provide the technology that will permit making the airplane unobtrusive in its environment," according to Johnson.7 Noise reduction would become a major OAST assignment. OAST also added a Military Aircraft Support Program Office to its roster of management tools in 1972.
Alan M. Lovelace, OAST Associate Administrator in 1976, publicly advocated that NASA should address high-risk technology development of potential near-term applicability as it related to fuel conservation, safety, and noise and emission reduction. In addition, NASA "is supporting the development of long-range technology that will provide major gains in performance, productivity, and commercial service. Thus, when the point of designing new military or commercial aircraft is reached, a major step forward can be made at lower technical and financial risk." Lovelace made NASA's role even clearer: "Aeronautical research and technology development will continue to be of vital importance to the U.S. as a factor in better transportation, greater military preparedness, and sustained world leadership. "8 The civilian agency would do this by doing three things: providing an improved understanding and confidence in the major technical disciplines; generating and demonstrating the technology required to alleviate current aeronautical problems and supporting anticipated next-generation systems; and establishing research foundations for advanced systems for the long-range future.
This kind of rhetoric was repeated by the next associate administrator, James J. Kramer, when he spoke before the Subcommittee on Transportation, Aviation, and  Weather of the House Committee on Science and Technology in 1977. He said that NASA agreed "completely that preeminence in aeronautics is absolutely vital to the national interest and that this point should be accepted as national policy." That preeminence depended on research and technology. Kramer also supported the view "that government activity should go beyond traditional research technology bounds and should extend to the point where results can be readily applied by industry."9 The number of NASA aeronautics projects rose over the second decade to meet these noble goals.
For many years, OART/OAST associate administrators had on their staffs a deputy associate administrator for aeronautics. Charles W. Harper, who had come from Ames Research Center, was director of aeronautics from 1964 to 1967, when he first became deputy associate administrator for aeronautics. Neil A. Armstrong took that post in the 1970 reorganization. It was dropped from the books from 1972 to 1973 and reclaimed by J. Lloyd Jones in 1974. In 1975, the position was once more left off the roster and was not reinstituted during the rest of the second decade. William Pomeroy and Albert J. Evans took turns serving as directors of aeronautical vehicles during 1969. In 1970 the management structure for aeronautics became much more complex. As noted above, there were three aeronautics-related divisions and a growing number of project/program offices to address special requirements (see table 5-1). NASA centers that played a major role in the aeronautics program included Ames Research Center, Flight Research Center, and Langley Research Center.
The following projects are examples of the types of activity OART/OAST was engaged in during its second decade. It is not a complete list but does include all major research and test flight projects.
General aviation. A General Aviation Technology Office was established within OAST in 1973 to develop the technology base for the design and development of safer, more productive, and superior U.S. general aviation aircraft.10 NASA was responding to the growing importance of the general aviation segment of the U.S. civil air transportation system and the ever-increasing number of hours flown and people, cargo, and mail carried and acres of crops serviced. A Panel on General Aviation Technology was added to NASA's Research and Technology Advisory Group, technical workshop series were initiated, and joint research efforts were undertaken. By 1976, the list of general aviation interests included stall-spin research, crashworthiness, pilot operations, flight efficiency, propulsion, avionics, environmental impact, and agricultural aircraft. 11
The objective of NASA's stall-spin research program was to provide design data and criteria for efficient light aircraft that will not stall or spin unintentionally. From wind tunnel and model stall-spin tests, the agency progressed to full-scale tests in 1976. Improved structural crashworthiness was another goal. NASA hoped to provide greater protection to passengers in the event of a crash through theoretical analyses and predictions of the dynamic behavior of aircraft structures under crash impact loads. An automated pilot warning and advisory system also was under development that would be of special value to general aviation pilots flying out of uncontrolled airports. Airfoils designed by the civilian agency were optimized for general aviation applications, improving the efficiency of light aircraft. NASA's work in the propulsion area was directed toward reducing the environmental impact of aircraft engines and improving fuel economy. During the late 1970s, NASA also  began to study how the agricultural community could more efficiently use the airplane to increase farm production.
Environmental factors. During the 1970s, NASA became committed to helping solve a number of problems associated with the negative impact that airplanes and airports have on the environment. To alleviate aircraft noise, the agency initiated a quiet engine program, demonstrated that existing engines could be refanned, and experimented with a new quiet, clean, short-haul engine. Aircraft atmospheric pollutants served as a catalyst to NASA's clean combustor program and a global air sampling effort. In addition, urban dwellers' complaints of large airport congestion and noise served to draw OAST into studies of these problems.
The quiet engine program, initiated in the late 1960s, led to demonstrations in 1972 of NASA's Quiet Engine with complete nacelle acoustic treatment to decrease the noise of the engines' fans. Noise levels were even lower than the original goals of the program; takeoff, flyover, and approach noise (effective perceived noise decibels) was reduced substantially. A Quiet Jet Propulsive-Lift Experimental Aircraft (QUESTOL) was built for NASA by Lockheed-Georgia Company in the 1970s to serve as a testbed for research on quieting jet transport aircraft. In another program, NASA modified the JT3D/JT8D jet engine to run more quietly by refarming it. The original two-stage fan was replaced with a larger single-stage fan. This engine powered a major portion of U.S. narrow-body commercial aircraft. The modified engine reduced the noise footprint by 75%. The Quiet, Clean General Aviation Turbofan (QCGAT) Program began in 1975 to ground test several general aviation turbine-powered engines. NASA also conducted research in an attempt to quiet the rotor and propeller noise of V/STOL aircraft.
NASA's programs in exhaust emission reduction included investigations to determine the effect of combustion temperature, pressure, and equivalence ratio on the generation of pollutants (smoke, hydrocarbons, carbon monoxide, and oxides of nitrogen). One specific project undertaken at the Lewis Research Center was clean jet engine combustor research. It was Lewis's goal to demonstrate that lower aircraft emissions could be reached without sacrificing either combustion efficiency or the combustor's ability to re-ignite in flight. Modified fuel nozzles and advanced fuel injection technology to control the combustion process were other areas under investigation. Related to these efforts was the Global Air Sampling Program (GASP). NASA began to gather measurements on the effects of pollution in the atmosphere in the mid-1970s by attaching sampling devices on airliners.
Along with the Department of Transportation, NASA was concerned with airport noise and crowding problems. In addition to its programs to reduce aircraft takeoff and approach noise pollution, the OART/OAST sponsored a number of studies of human behavioral responses to airport noise. An Aircraft Noise Reduction Laboratory was constructed at Langley Research Center.
V/STOL aircraft. NASA initiated a V/STOL research program in the 1960s and continued this activity during the second decade. VTOL research involved the development of advanced flexible navigation, guidance, and control avionics to improve the operational efficiency, public acceptance, safety, and reliability of these vehicles. One major goal was an automatic takeoff and landing system for helicopters. With the Department of Transportation, NASA sought to develop a data base for use by industry and government agencies in establishing system concepts, design criteria, and operational procedures for STOL aircraft. An advanced  integrated avionics and display (STOLAND) system was developed to perform navigation, guidance, and control tasks during the mid-1970s. NASA and the Canadian Department of Industry, Trade, and Commerce sponsored a joint program to test the Augmentor Wing Jet STOL Aircraft, an extensively modified C-8A military transport craft. This research program explored at low speeds the interrelationships between aerodynamics, handling qualities, and performance of the augmentor wing concept. This concept integrated aircraft engine, wing, and flap in order to increase aerodynamic lift, a concept investigated for potential use in STOL jet transports.
Supersonic/hypersonic research. In addition to the lifting body program discussed above, NASA conducted several other flight and wind tunnel research programs to investigate the designs and handling characteristics of aircraft at supersonic and hypersonic velocities. The popular X-15 program had come to an end in 1968, the agency having exhausted the research potential of that aircraft. NASA's part in the search for a national Supersonic Transport Aircraft also ceased as that program was cancelled in 1971. NASA and Air Force test pilots used the YF-12 research aircraft in a supersonic flight program during the early 1970s, but NASA's interest in advancing supersonic technology was restricted to making supersonic flight efficient with low noise and environmental impact. In addition to manned flights and wind tunnel tests, the agency evaluated the advantages of using remotely piloted research vehicles for flight research involving hazardous or new high-risk aircraft concepts. The Firebee II is an example of this type of aircraft, used by the Lewis Research Center in the mid-1970s in support of a future highly maneuverable aircraft (HIMAT).
Military support programs. Advising the military on aircraft research needs had been one of the National Advisory Committee on Aeronautics's primary jobs during the decades before NASA was established. During the 1970s, NASA expanded its support of the Department of Defense in maintaining the superiority of military aircraft. NASA and the Air Force had been working together since the late 1950s in their evaluation of the X-series of research aircraft, lifting bodies, and other high-speed experimental aircraft, but the civilian agency took a broader role in the military after the 1970 reorganization of OART.
NASA assisted the military by developing advanced technology suitable for future military systems and providing direct technical support to specific aircraft programs to enhance the success of their development. Such programs include the F-15 fighter, B-1 bomber, YF-16, YF-17, and F-18. The Highly Maneuverable Aircraft Technology program was initiated as a result of Air Force interest. From work with drones and remotely piloted research vehicles, the two agencies planned to testfly two vehicles in 1979. With the Army, NASA worked on two helicopter projects: the Tilt Rotor Research Aircraft (XV-15) and the Rotor Systems Research Aircraft. These custom-designed vehicles were readied for flight tests in 1976 and 1977. The Rotor Systems Research Aircraft used both its rotor system and wings to develop lift; advanced rotor concepts would be tested on it. Tilt-rotor handling and control characteristics were evaluated with the other research vehicle, as well as automatic landing systems. For fighter aircraft, NASA worked on supercritical wing technology. A modified F-8 supersonic fighter was used to evaluate a new airfoil shape as part of the joint USAF-NASA Transonic Aircraft Technology (TACT) Program.
* OART was established as part of the November 1961 agency wide reorganization. For more on the management of advanced research projects during NASA's first decade, see vol. 2.