Journal of Aerospace Engineering

This paper presents a brief overview of air-breathing propulsion research conducted at the National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) over the last 70 years. It includes a historical perspective of the center and its various stages of propulsion research in response to the country’s different periods of crises and growth opportunities. The GRC’s research and technology development covered a broad spectrum, from a short-term focus on improving the energy efficiency of aircraft engines to advancing the frontier technologies of high-speed aviation in the supersonic and hypersonic speed regimes. This paper highlights major research programs, showing their impact on industry and aircraft propulsion, and briefly discusses current research programs and future aeropropulsion technology trends in related areas.

This paper reviews all engine noise research conducted at the National Aeronautics and Space Administration (NASA) Glenn Research Center over the last 70 years. The review includes a historical perspective of the center and the facilities used to conduct the research. Major NASA noise research programs are highlighted, showing their impact on the industry and on the development of aircraft noise reduction technology. Noise reduction trends are discussed, and future aircraft concepts are presented. Results show that, since the 1960s, the average perceived noise level has been reduced by about 20 dB. Studies show that, depending on the size of the airport, the aircraft fleet mix, and the actual growth in air travel, another 15–17 dB is required to achieve NASA’s long-term goal of providing technologies to limit objectionable noise to the boundaries of an average airport.

NASA Glenn Research Center (GRC) has been involved in a wide range of combustion research topics in combustor concept research, component technology development, and enabling technology development to provide enabling technologies for flight regimes from subsonic to hypersonic. These research efforts were carried out by NASA and industrial and academic partners through a range of NASA fundamental research and focused programs. These synergistic efforts in fuel injection, flame stabilization, combustion physics, and ignition studies have resulted in combustor concept changes that resulted in much cleaner-burning modern jet engines. New computational tools, optical diagnostics, fuels, and fuel conditioning technology are being currently used to develop a better understanding of the complex processes occurring in combustion systems for a range of future propulsion systems.

The National Aeronautics and Space Administration Glenn Research Center (GRC; and its predecessor organizations) has been and continues to be a focal point for research in the field of aircraft icing. This paper provides a historical perspective on the contributions that GRC research has made to the field, as well as a synopsis of the current research being conducted at the center. The GRC’s icing research has been comprehensive, covering the characterization of the icing environment, investigations into the physics of ice accretion on aircraft surfaces, studies of the impact of icing on aircraft aerodynamics and engine performance, icing instrumentation development, and simulation of ice growth on aircraft using wind tunnels and computational methods. This research has led to improved safety for flight in icing conditions through contributions to the development of icing regulations; a greater understanding of the effects of ice accretion; and the development of experimental and computational methods to aid in the design of aircraft and aircraft subsystems (including ice protection systems) that can operate safely in an icing environment.

Development and contributions to computational fluid dynamics (CFD) at the National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) during the period from 1947 to the present are reviewed in five categories: numerical methods, physical modeling, CFD codes development, CFD validation and engineering applications, and multidisciplinary design optimization. Some representative results in applications to aero and propulsion systems are included to illustrate the developed capabilities. GRC has a long history of investing resources to develop these key subject matters, with an interest in a wide range of applications, primarily focusing on propulsion-related technologies and concepts. The evolved CFD capabilities have enabled simulations of complex three-dimensional flow fields for engine components and integrated configurations, as illustrated in this article. This article is intended to give a useful, albeit noncomplete, overview into GRC’s work in CFD.

Propulsion and power have long been core competencies of the National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC). At the dawn of the space era, the center brought key propulsion and power technology to support spacecraft development. This paper serves as an introduction to a series of papers describing the highlights of the GRC’s power and propulsion research and development efforts. The power papers cover solar and nuclear power generation and energy conversion, energy storage (focusing on batteries, flywheels, and fuel cells), power systems, and power management and distribution. The propulsion papers cover chemical propulsion, cryogenic propellant systems, electric propulsion, and nuclear thermal rocket propulsion. Each paper addresses some history, current efforts, and future plans for each of the technology areas.

This paper provides a brief overview of the history of electric propulsion (EP) at the National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC). Since the inception of EP technology, GRC has played a pivotal role in developing the technology and transitioning it to flight. Research and development efforts by GRC’s employees, grantees, and contractors brought operational EP systems to commercial satellites in the early 1990s and to NASA and other government agency missions starting in the late 1990s. GRC’s early construction of unique EP test infrastructure and NASA’s and GRC’s sustained investments in EP research and development over several decades were strategic in the creation of technologies that continue to greatly benefit the competitiveness and capabilities of U. S. space systems and missions.

The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) was built during World War II with the primary objective of catching up with the Germans in jet engine technology. A decade later, it seemed only natural that these same aeropropulsion engineers would progress into the largely unexplored field of space chemical propulsion. Starting before the launch of Sputnik set off the great space race, researchers at the GRC were testing and flying cryogenic hydrogen-fueled engines that were an eventual key to the success of the Apollo manned missions to the moon. In the 60 years since this first foray into chemical propulsion, engineers at the GRC have made countless innovations and contributions to every component of rocket engine technology. From energetic propellants to green fuels, from innovative metallic alloys to ceramic composites, from seals and bearings to igniters and injectors, and from upper stages and satellites to launch vehicles and planetary landers, the dedicated and creative people at the GRC have propelled the United States to the forefront of space exploration and continue to work toward an even more exciting future. Some of the highlights of this illustrious and ongoing journey are explored in this paper.

The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) has been actively involved in nuclear thermal propulsion (NTP) technology development, mission, engine, and vehicle design dating back to the Rover and Nuclear Engine for Rocket Vehicle Applications programs. This technology was successfully developed in over 20 rocket/reactor tests, which demonstrated a wide range of thrust levels, high-temperature fuel, sustained engine operation, accumulated time at full power, and restart capability—everything required for a human mission to Mars. Furthermore, NTP requires no large technology scale-up. The smallest engine tested during the Rover program—the Pewee Engine—is sufficient for this when used in a clustered engine arrangement. The GRC has led every major study involving NTP since the late 1980s and has helped quantify the evolution and growth potential of the nuclear thermal rocket (NTR), which includes the bimodal and liquid-oxygen- (LOX-) augmented NTR concepts. In NASA’s recent Mars Design Reference Architecture (DRA) study, NTP reduced total mission mass over 400 t compared with chemical propulsion. Human missions to the Moon and near-Earth asteroids are also enhanced using NTP. In 2011, NASA restarted an NTP technology demonstration effort that is continuing under the Nuclear Cryogenic Propulsion Stage project, which began in 2012. Ground demonstrations of a small, scalable NTR by 2020 are envisioned, with a flight demonstration shortly thereafter.

The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) began experimentation with cryogenic propellants in the early 1950s to understand the potential of these high-performance propellants for use in liquid propellant rocket engines. Supporting these tests required learning how to both design cryogenic systems and develop procedures to safely and reliably work with cryogenic fuels and oxidizers. This early work led to the development of a skill set that has been core to the center ever since. When NASA was formed and the exploration missions were defined, it became clear that the ability to use cryogenic propellants in the thermal and microgravity environment of space was critical to mission success, and the agency was tasked with enabling this capability. To support development of the Centaur upper stage and the Saturn S-IVB stage, GRC researchers and engineers initiated extensive technology development for the in-space application of cryogenic fluid management (CFM). These initial efforts addressed basic requirements of propellant slosh, settling, and short-term storage/pressure control. Over the ensuing years, the NASA GRC has advanced CFM technologies to enable more reliable and capable upper stages. Today, these CFM technologies are on the brink of enabling long-duration in-space cryogenic propulsion stages and cryogenic propellant depots.

The National Aeronautics and Space Administration Glenn Research Center (GRC) has an extensive history in dynamic energy conversion dating back to the early 1960s. This legacy puts the GRC at the forefront of nuclear power systems using thermodynamic power cycles such as Stirling and Brayton. The advantages of dynamic energy conversion include high efficiency, long life, and scalability to high power. These attributes make Brayton and Stirling power cycles an ideal solution for nuclear energy conversion.

The National Aeronautics and Space Administration Glenn Research Center (GRC) has a rich heritage of developing electrochemical technologies and energy storage systems for aerospace. Primary and rechargeable batteries, fuel cells, flywheels, and regenerative fuel cells are among the GRC’s portfolio of energy storage devices and primary power systems. These technologies have been developed for missions and applications such as low Earth orbit and geosynchronous Earth orbit satellites, space shuttle, astronaut spacesuit, International Space Station, landers and rovers, and lunar and planetary habitats. The desire for lower mass, lower volume, higher efficiency, and more reliable power systems has most often been the driving force behind the development of these technologies. Often, as with fuel cells for the early Gemini and Apollo missions, development of the technology has been mission enabling. Although many of these technologies were initially developed for applications in space, the existence of such capabilities or development successes at GRC has led to their adoption for terrestrial uses or further research and development for terrestrial applications, including electric vehicles, unmanned aerial and underwater vehicles, and all-electric aircraft. This paper discusses the history of and the current research and development at the GRC in electrochemical and energy storage technologies. The future outlook for each of these technologies is also addressed.

This paper explores the organizational history of the three core discipline areas currently residing within the Communications, Instrumentation, and Controls Division, which are harsh environment instrumentation/sensors/electronics, turbine engine controls and systems dynamics, and aerospace communications technology. Division and selected branch management will be identified by discipline in chronological order. In the second section, current division research areas will be listed by branch. Finally, future progress in the key disciplines is discussed by describing near-term future work and projecting a long-term future state beyond the horizon.

Over the last several decades, the National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC), formerly Lewis Research Center (LeRC) has performed research and technology development of aeronautic- and space-based communications in support of NASA and the nation. In the 1970s, GRC partnered with the Canadian Department of Communications through the Communications Technology Satellite (CTS) Project, in which GRC researchers were responsible for the development of critical technology components, such as the high-power, traveling-wave tube amplifier (TWTA), thereby pioneering the surge of television channels via satellite. For its efforts, LeRC was awarded an Emmy by the television industry. The decade of the 1980s served as a period for technology development that culminated in the launch of the Advanced Communications Technology Satellite (ACTS) in 1993. The ACTS demonstration of spot beam antenna technology resulted in an overall increase of efficiency in satellite communications. In the latter part of the 1990s and until today, GRC research engineers have continued to conduct research and technology development in multiple domains. The primary focus of this article is to introduce the reader to the long heritage at GRC in communications research and development through the CTS and ACTS projects and delve into specific technology areas following the ACTS Project to today in support of high-data rate communications.

This paper is a transitory decadal overview capturing the current research and technology accomplishments that are being developed by the Optical Instrumentation and Nondestructive Evaluation (NDE) Branch at the National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC). The emphasis is on the latest GRC research and technology advances with a brief discussion of the history and technical background of optical instrumentation since the 1940s, NDE sciences and methods since the 1970s, fiber optics since the 1980s, space-qualified instrumentation since the 1990s, and propulsion health monitoring since the beginning of the current century. This paper also identifies and describes recent and future technical directions based on/guided by current NASA strategic and GRC and NASA project implementation plans.

Throughout the 70-year history of the National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC), instrumentation engineers have provided measurement methods and devices necessary to support ongoing and future aeropropulsion research and development efforts. On occasion, routine instrumentation approaches are perfectly suited for the task at hand. However, as propulsion components and systems become more complex through the incorporation of new materials and higher temperature operation, modifications to traditional instrumentation methods or entirely new methods are necessary. This paper provides a glimpse of the core electronic-based instrumentation methods developed throughout the years to measure temperature, strain, pressure, heat flux, and chemical gas species and describes how these methods are evolving to meet the instrumentation challenges of high-performance propulsion systems. It is clear that future aeropropulsion systems will operate at higher temperatures and require more onboard electronics for health monitoring and control functions. For this reason, a significant effort in high-temperature electronics based on the wide-bandgap semiconductor silicon carbide was initiated and has demonstrated several world’s first electronic sensors and devices operating at 600°C. It is concluded that electronic-based sensors and devices will continuously be pushed to meet the needs of increasingly harsher environment measurements.

This paper provides an overview of the aircraft turbine engine control research at NASA Glenn Research Center (GRC). A brief introduction to the engine control problem is first provided with a description of the state-of-the-art control law structure. A historical aspect of engine control development since the 1940s is then provided with a special emphasis on the contributions of GRC. With the increased emphasis on aircraft safety, enhanced performance, and affordability, as well as the need to reduce the environmental impact of aircraft, there are many new challenges being faced by the designers of aircraft propulsion systems. The Controls and Dynamics Branch (CDB) at the GRC is leading and participating in various projects to develop advanced propulsion controls and diagnostics technologies that will help meet the challenging goals of NASA Aeronautics Research Mission programs. The rest of the paper provides an overview of the various CDB technology development activities in aircraft engine control and diagnostics, both current and some accomplished in the recent past. The motivation for each of the research efforts, the research approach, technical challenges, and the key progress to date are summarized.

At the dawn of the Space Age, the design of early rocket and spacecraft systems presented significant challenges because of the low-gravity environment of space. Motivated by these challenges, the National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) pioneered the development of low-gravity facilities—including drop towers, sounding rockets, zero-gravity (zero-g) aircraft, and most importantly, space-based facilities—to advance microgravity research to further the nation’s space exploration efforts. These efforts resulted in improved spacecraft system designs and practices in areas as diverse as fluid handling and spacecraft fire safety. At the same time, researchers realized that the microgravity environment allows the study of fundamental combustion and fluid physics problems, without the complication of buoyancy-induced convection. Microgravity testing enabled advancements in areas of technological and ecological importance in terrestrial applications such as global atmospheric change, combustor design, groundwater pollution, oil production, and advanced materials manufacturing, which often rely on advances in fluid physics and chemically reacting flows. GRC has been a leader in microgravity fluid physics and combustion research for more than 50 years. This paper highlights the facilities and some of the many accomplishments.

Throughout the 70-year history of NASA Glenn Research Center (GRC), technology development efforts that promoted advancement in aeronautics technologies, aerospace sciences, materials for hostile environments, and microgravity physics have also enabled the maturation of technologies that have affected medical practice on Earth, in the air, and in space. GRC’s unique skill mix, required for aeronautics research and space exploration, ultimately also advanced the development of a wide array of capabilities applicable to biomedical engineering. This paper presents a historical review of notable biomedical endeavors at GRC that have addressed common and uncommon medical conditions afflicting both astronauts and non-astronauts. It also highlights the unique physiological stressors associated with residing in space. The physiological changes associated with these stimuli present evolving challenges for researchers to devise new and innovative medical interventions and technologies.

The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) is well recognized for its contributions toward development of advanced materials and structures for aerospace propulsion and power systems. The Structures and Materials Division conducts research across a broad range of technical areas relevant to the agency’s future aeronautics and space mission requirements. This paper will introduce the technical areas of strategic importance in the Structures and Materials Division today and briefly address some of the specific research activities within these areas. A broad look at how the research areas of emphasis have evolved over time, beginning in the early 1940s when the GRC was first formed, will be discussed. Examples of some of the more notable research accomplishments and their impact on the aerospace industry over this time period will be included. A discussion of the division’s planned technical directions believed to be required to meet the longer-term national aeronautics and space exploration goals will also be addressed.

Research in smart materials and active structures has grown significantly at the National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) in the last 10 years. The GRC has achieved several promising results in both new material development and component applications for concepts using both shape memory alloys and piezoelectric ceramics. Progress in understanding and modeling of shape memory alloys has allowed for improved design and control methodologies. New high-temperature alloys with attractive work output have extended the capability from room temperature to ∼350°C. Finally, the list of successful prototype demonstrations continues to grow for both commercially available alloys and the newer high-temperature alloys. Analytical and experimental methods on piezoelectric blade vibration damping have produced the first successful demonstration of vibration damping on a rotating component. The damping levels achieved lead to reduced dynamic stresses, hence increased engine life and enhanced damage tolerance. In addition, new compositions have been developed to extend the temperature capability of high-performance piezoelectrics to near 400°C. These new materials are just now showing laboratory-scale feasibility and are targeted for continued development.

Within the Structures and Materials Division at the National Aeronautics and Space Administration Glenn Research Center (GRC), research is being conducted to develop durable high-temperature materials for the most challenging aerospace applications. Research is advancing material and coating technologies for applications including turbine engine hot section components, rocket engine combustion chamber liners, high-temperature components of advanced space power systems, and atmospheric reentry vehicle surfaces. As part of the volume of papers recognizing 70 years of research at the GRC, this paper summarizes key research contributions that GRC has made to the field of high-temperature aerospace materials.