Maintaining U.S. Leadership in Aeronautics: Scenario-Based Strategic Planning for NASA's Aeronautics Enterprise (1997)

Each of the five future scenarios that were considered at the workshop is discussed in separate sections of this chapter. They are entitled "Pushing the Envelope," "Grounded," "Regional Tensions," "Trading Places,'' and "Environmentally Challenged." Each section contains a short summary of the scenario as it was provided to the working group.¹ This is followed by a discussion of the role of aviation and aeronautics and a listing of needs, opportunities, and their implications for aeronautics technology as determined by the working group that focused on the scenario throughout the workshop.

"Pushing the Envelope" is a scenario characterized by a continuously growing, strong global economy and an affluent and growing middle class. The United States also has a strong economy, with liberal trade policies and a laissez-faire attitude toward business and commerce. The worldwide demand for aeronautics and space-based products and services is strong and the free market economy is generating rising employment and prosperity throughout the world. Local and state governments are privatizing many of their services while opening up new markets

for private investment. Technology has generated many new products and services while creating much shorter product life cycles. Trade barriers have crumbled as capital freely crosses international borders. In many cultures, market-based environmentalism is becoming a driving force. Quality of life is improving as consumers "dial in" on the Internet for more goods and services. The world is at peace and the role of the U.S. military is primarily one of deterrence and policing in such trouble spots as the Middle East. This role requires the military to focus on the protection of its personnel while using only enough force to control a situation without causing massive casualties. The military also relies on commercial assets to support many logistics and communications functions.

An examination of the aviation marketplace reveals that the consumer is king. There is a worldwide demand for low-cost, efficient air service. Safety, performance, and customer service also are important. The increase in air travel has generated a growing demand for new aircraft products and services. Refurbished passenger and cargo aircraft are in high demand as manufacturers try to keep up with demands for new aircraft orders. Consumers, with their new-found wealth, are ordering more products through the Internet, which is creating a growing need for air cargo service. Business travel is at an all-time high, and transoceanic flights are generally overbooked. Emerging markets in China, India, South America, and Eastern Europe are generating large backlogs for new aeronautics products that will take manufacturers many years to fulfill. Strong, competitive forces dominate the marketplace as demand for services increases.

More and more business is being carried out face to face with customers and partners around the world because efficient capital markets and competitive market forces have generated many global alliances of convenience. Businesses also are sharing resources as they compete for growing market segments. Customer satisfaction is not just a slogan, but a requirement for business survival. The growing use of the Internet and advanced telecommunications has created a need for "just-in-time" products and services. Affordability, dependability, and reliability are the buzz words for a growing air cargo market. Prompt, efficient, and on-time service is a requirement for those companies that ship products by air.

To satisfy this growing air travel market, several needs and opportunities were identified for aeronautics and are discussed below.

The wide number of air travel choices available to consumers in this scenario would create a highly competitive marketplace and a demand for efficient, low-cost air passenger service. For air carriers, meeting this demand while remaining profitable would require low total operating costs, including low-cost systems and procedures related to aircraft maintenance, repair, and overhaul. Large-volume aircraft, reconfigurable aircraft, and supersonic transports also would be required to maximize the efficiency of air travel and meet the growing demands of both consumers and air carriers. Each of these aircraft types would be designed with both low production costs and low operating costs, and short cycle times for design, fabrication, and certification processes would be required for new aircraft products.

Another air carrier response to increased competition would be to offer customized services enroute that are based on the demands of the market segment. Examples include entertainment options, such as gambling for leisure travelers, or improved access to the office for business travelers. As a result, a wider variety of aircraft products, including reconfigurable aircraft, and closer involvement of customers in the design and manufacturing of new aircraft products, would be the norm.

To handle the increased throughout of aircraft, people, and cargo that exists in the "Pushing the Envelope" scenario, investments in existing transportation infrastructure would need to be increased. New types of airports, including heliports, would be needed, and fast, efficient access to these airports would need to be found. Mass transit systems would need to be fully integrated with rotorcraft and tiltrotor operations by co-locating heliports with bus and rail stations and by coordinating passenger pick-up and drop-off schedules with aircraft arrivals and departures.

In highly developed nations, opportunities for new full-service airports would remain limited due to geographic and environmental constraints, as would increased operations at existing airports. This would create technological challenges to increase passenger and cargo capacity without greatly increasing the frequency of flights.

Improvements in ground-based air traffic management (ATM) integrated with on-board ATM would be required to handle the increased volume of air traffic with the efficiency and safety that would be demanded by the public. Automated air traffic control (ATC) using satellite-based communications, navigation, and surveillance systems with increased data-handling capabilities and improved weather sensing and modeling would be a must. Technology that allows aircraft to avoid adverse weather autonomously also would be required, and enhanced adverse weather landing capabilities would need to exist at most airports. In general, improved situational awareness systems would be required in the aircraft and on the ground.

Although threats to security are generally low in this scenario, sophisticated sensing equipment and security measures would be needed to protect a large and growing number of air travelers. To reduce overall accident rates despite a large increase in the number of takeoffs and landings, aircraft would need to be designed, maintained, and operated in a manner that reduces human error. Advanced cognitive engineering techniques; automatic fault detection and correction systems; built-in, error-free system interfaces; and stringent safety procedures would be required.

Although environmental protection is more market based in this scenario, it remains important to most consumers. Therefore, supersonic aircraft would require technology that would reduce sonic boom effects so as to make overland flights at supersonic speeds acceptable. In addition, all aircraft would be required to meet or exceed noise-level requirements beyond Federal Aviation Regulation (FAR) Part 36, Stage 3, to further reduce noise pollution.² Aircraft exhaust pollution emissions also would need to be greatly reduced.

Twenty-four hour, on-time, adverse weather capabilities would be required for air cargo service providers so that shipments arrive on schedule. Modern facilities that

enable fast and efficient cargo handling and sophisticated cargo-tracking capability through the use of common intermodal interfaces and advanced custom-tailored information technology would be needed. Safety and security requirements would be similar to those of passenger service.

Competitive market forces would drive the commercial launch vehicle and satellite businesses toward low-cost service with increased reliability. Advanced air-augmented or air-breathing propulsion systems could be used on some launch vehicles if they proved to be cost effective. The U.S. military would continue to require dedicated space capabilities for global command, control, communications, and intelligence (C³I), as well as navigation and surveillance. For both commercial and military space activities, the reduction of orbital debris would be a priority. This could create requirements for fully reusable launch vehicles that leave no components in orbit.³ Launch vehicles that are robust enough to withstand debris impacts while in space also could be required.

Effective partnership between academia, industry, and government would be required to maximize the efficient use of research and development (R&D) dollars. Increased use of peer review for the allocation of federal R&D funding would be a priority of this partnership, as would increased emphasis on technology verification and technology transfer.

To support the global responsibilities that the U.S. military would have in this scenario, rapid reaction and deployment of military forces would be required. These deployments could require the substantial use of commercial assets for air transport and space-based communications and remote sensing. Adverse weather, modular, robotic, or autonomous smart weapons systems also would be needed for stand-off weapons delivery and defense. In general, emphasis would be placed on the reduction of casualties, the protection and survivability of high-value delivery systems, and the total cost and effectiveness of military operations. The use of

nonlethal weapons systems to achieve the required military objectives would be a highly desirable option.

The "Grounded" scenario is characterized by a world victimized by unprecedented, unpredictable, and anonymous large-scale violence and terrorist actions. A long period of rapid, global economic growth has served to widen the gap between the well-to-do, skilled, professional work force and unskilled and semiskilled workers, especially in developing nations. Angry, bitter, jealous people in socioeconomic groups that have been left behind are resorting in frustration to random acts of violence against large masses of people wherever they can be targeted. All forms of mass transit, large public gatherings, and dense urban environments are now avoided, if possible.

To keep the global economy healthy, the U.S. government has embarked on a massive program to significantly upgrade and expand the Internet system on a global basis. The new U.S. standard Global Information Network or "G-net" is now the worldwide standard.⁴ With a massively increased bandwidth and a greater number of applications, the G-net has become the backbone of global commerce and an acceptable (and cost-competitive) alternative to all but the most essential travel. All aspects of society, including commerce, government, culture, and entertainment flow continuously and globally through the G-net. The global economy's vitality is sustained by the G-net and the rapid pace of technological advance, product innovation, and entrepreneurship that it enables. "Virtuality" has replaced "being there."

Onerous and very expensive security measures, enacted to counter the threat of random violence and terrorism, have increased significantly the cost of most forms of public transportation, especially air travel. High cost and fear have combined to eliminate most discretionary air travel. For the small amount of personal air travel that is still conducted, unscheduled, point-to-point flights from more distributed, smaller airfields have replaced the large hub and spoke system of today. To more closely control security, most businesses operate their own aircraft fleets or charter small commercial jets in lieu of using commercial carriers. In many cases, families and individuals who must travel also feel more secure flying themselves or arranging for individual charters. As a result, general aviation also experiences some growth in this scenario.

Even though the G-net enabled a global economy and strong U.S. economic competitiveness, the movement of goods over great distances would still be required, even though cargo shipments would occasionally be at risk from terrorism. This would create the need for a new, specialized, subsonic, large-payload cargo aircraft with a global range for time-critical cargo delivery to a fast domestic distribution system.

Commercial and business travel that is not conducted using private fleets or chartered aircraft would be accomplished by air carriers using a new generation of lower-capacity transports that also operate within a more distributed, point-to-point air transportation system. The premium prices paid by those who still must travel would create a demand for premium services, including aircraft interior configurations customized to meet passenger requirements, and supersonic capability for long-range overwater routes.

The increase in general aviation (GA) activity would create a need for low-cost, reliable, user-friendly GA aircraft that operate much more like an automobile and have more adverse weather capabilities than today's aircraft. The G-net would play an important role in GA by enabling an extensive network of flight training and

simulation capabilities to be delivered directly to the home. These capabilities would enhance both the safety and security of personnel by reducing exposure to actual flight hazards, including terrorism.

Counterterrorist special operations and rapid response to regional flare-ups would emphasize the need for a stealthy, long-range, special operations forces vehicle that operates from unimproved fields with short take-off and landing capability and, in some cases, vertical capability.

For all classes of aircraft, the incorporation of a wide range of survivability features would be required to maximize customer safety. In many cases, these systems would be derived from military activities and research programs. Aggressive technology development activities that benefit both military and commercial requirements would be needed so that many of these features would be affordable for general application. These features include a full range of threat detection and mitigation systems, including bomb detectors and missile launch detectors, missile countermeasures such as infrared signature reduction, and electromagnetic interference and laser aircraft hardening. Threat avoidance operations that use high-lift or vertical-lift capability to minimize exposure to ground-based threats (such as shoulder-mounted missiles and small arms fire), and survivable aircraft features (such as reconfigurable controls, adaptable control surfaces, and survivable structures) also would be needed.

Ground security measures would be extensive and would include expanded airport security perimeters (i.e., gated entrances to airport property), as well as improved screening of personnel, passengers, cargo, and baggage. The real-time access to worldwide databases on the G-net would further enable a rapid, highly reliable system to identify and profile all passengers.

Point-to-point operations that use lower-capacity commercial transports, business jets, and GA aircraft would need to be supported by a sophisticated distributed airspace system with automated decision making for ATM. Technology to provide accurate, user-friendly situation awareness and decision aids directly to the cockpit by way of secure and reliable data links would be needed.

To establish and maintain the network of communications and navigation satellites inherent in this scenario, a low-cost, on-demand, low-Earth orbit (LEO) launch capability is paramount. A new generation of extremely small, lower-weight satellites would allow the development of a reduced-cost, unmanned orbital insertion vehicle.

The computational and networking capabilities that exist in the "virtual" environment of this scenario would enable an entire spectrum of modeling and simulation capabilities that could transform many industries, including aeronautics. Product development lead times and manufacturing costs would be slashed, and an entire new standard of reliability would be established, provided that technology is developed to

• improve the modeling of aerodynamics, propulsion, and structures using fundamental physical laws rather than empirical data

• improve process modeling and human-machine interface modeling

• enable virtual manufacturing, assembly, and even testing

The future world of "Regional Tensions" is characterized by weak U.S. economic competitiveness, a high growth rate of worldwide demand for aeronautics products and services, a high level of threats to security and quality of life, and a high global trend in government participation in society.

The world has organized itself into regional trading blocs, ending a period of harmonious globalization. Japan, Russia, and India have formed an alliance so as to compete with China. An Anglo-American bloc has emerged including Australia, New Zealand, Taiwan, the United States, and the United Kingdom. The remainder of the European Union takes no sides and attempts to sell its goods to any nation.

Rapid change and regionalization have made the world uncertain and uneasy, although it is still at peace and has nominally open trade practices. The United States has lost many of its markets and manufacturing capabilities within the competing regions. The United States is in an ambiguous position, with the need to prepare for potential hostilities because of regional tensions while also recognizing the need to strengthen its economy by increasing trade within its region and restoring trade with other regions. The nation's strategic goals in this scenario, as determined by the world team, are to protect home regions, ensure the supply of critical natural resources and energy, prevent world war, contain expansion by potentially hostile nations, recover interregional markets, and unify U.S. society.

As a result of the goals stated above, the United States has turned its attention inward and allowed the government more control so as to mobilize the nation for action. The government is investing its aeronautics R&D resources almost entirely in military projects, although it insists that these resources have an inherent dual civilian use. The government also is expanding aeronautical education programs so as to use domestic talent to replace the skills lost to overseas competitors.

Several features of this scenario affect commercial aviation. The International Civil Aviation Organization (ICAO) and the World Trade Organization (WTO) are no longer functional, having removed their organizing influence in their respective domains affecting aeronautics. Oil is in sufficient supply, but at a high enough cost to encourage fuel conservation. Nevertheless, the tempo of international air travel is high. Within the United States, little capital is invested in ATM and related infrastructure. However, the dispersion of industrial facilities for both military and economic reasons has increased the requirement for flexible air traffic routing to and from minimal-sized, distributed landing fields.

Environmental issues have a reduced priority in society and therefore have little impact on aviation. However, the global spread of infectious diseases that are attributed to the high tempo of international air travel is an ongoing concern.

The global situation in the ''Regional Tensions" scenario, as reflected in the U.S. strategic goals, would result in the following compilation of needs that would have consequences to aeronautics:

• regional industrial capabilities to produce a wide variety of defense and commercial vehicles at reduced cost but without low-cost labor

• a skilled domestic labor force, including engineers, scientists, and shop workers trained by an education system that is focused on achieving broad-based participation from all segments of a diverse society

• a rapid, reliable, and flexible distribution capability for manufactured products

• an ability to project military force

• alternative domestic energy sources

• secure, reliable communications and information systems

• military and industrial intelligence gathering capability

• air transportation systems that enable operations in both existing, sophisticated infrastructures and new, but austere infrastructures

• appropriate defensive military capability

• prevention of the spread of infectious diseases by global air travel

Eight system level aeronautics technologies have been identified that would meet these needs. They are summarized below.

To produce aircraft that can operate efficiently in domestic service without investment in new ATC infrastructure and would also be attractive to customers in overseas markets with austere infrastructures, an autonomous, self-contained airborne ATC system would be desired. It would employ on-board information systems that use cooperative aircraft position information that is broadcast by satellite. These systems would provide navigation, collision avoidance, terminal landing, and adverse weather avoidance capability.

Example technology requirements are increased bandwidth capacity for reliable communications and data management, reduced pilot workload, improved computer algorithms for collision avoidance, and integration within the existing ATC system.

To make the best use of scarce resources and compete strongly for foreign market share, a new type of aircraft factory would be needed that builds on the knowledge and information technology strengths available in the United States. This factory would be "virtual" in the sense that the contributing units would operate as a cohesive whole even though separated physically for security and economic reasons. The products manufactured by the factory would include many types and sizes of aircraft, providing variations of basic and reconfigurable systems. Product attributes would be optimized by means of total system optimization design tools.

The principal technology requirements would be integrated product design, manufacturing, and certification capabilities that enable new aircraft to be designed, developed, manufactured, and sold within one year⁵; integrated learning systems for equipment, products, and manufacturing processes; and rule-based "expert" systems that support innovation and universal tooling.

To penetrate emerging markets within our region and undeveloped portions of other regions, a vehicle needing minimal-sized landing areas, with autonomous ATC and austere operating capabilities, would be extremely desirable. This aircraft also would serve as a multirole (e.g., special forces) military transport and could be used for the short-haul, dense domestic market to support dispersed manufacturing facilities with minimal impact on the existing infrastructure. Vertical/short take-off and landing technologies would be required for this aircraft, as well as integrated propulsion and airframe approaches to noise reduction; low specific fuel consumption, high thrust-to-weight ratio engines; autonomous ATC; and advanced manufacturing techniques.

To project military force and distribute high-value industrial products efficiently, a global range, supersonic transport would be required. The aircraft's high velocity would increase its productivity by increasing the amount of cargo or personnel that could be delivered within a given period of time. When used to carry passengers, the large seating capacity would reduce the burden on the ATC system and airport infrastructure. Technology to reduce the aircraft's sonic boom while traveling over land would be required, as well as non-afterburning supercruise engines and low

supersonic drag aerodynamic configurations, which could possibly be achieved by a modification of the oncoming airflow with beamed energy.

To capitalize on the existing domestic workforce, the number of college graduates with degrees related to aeronautics would need to be increased dramatically. Universities would have to provide an initial core education (to allow flexibility in later years), followed by specific training that uses industry as the campus. This would be both supported and facilitated by government funding.

Uninhabited air vehicles (UAVs) would be employed for a number of military and civilian activities, including communications, surveillance, intelligence gathering, local weather observation, aerial combat, and even cargo transport. UAVs would be chosen for these missions because they offer the best combination of long-term endurance, long range, low cost, and low observability, while removing the pilot and crew from exposure to hostile environments. The key technology requirements are improved understanding of human-machine interactions; reliable and secure communications links; flexible and modular payload configurations; low fuel consumption engines for high-altitude operation; and inexpensive, flexible manufacturing techniques.

Controlled observability and low-noise technologies are key areas of technology in their own right, and together are usually referred to as stealth technology. In this scenario, the military would apply the knowledge gained from years of advanced stealth technology R&D to the design and production of weapons systems that can locate, target, and destroy enemy stealth aircraft. On the commercial side, some stealth technology would be desirable to minimize the threats to passengers posed by terrorist missile attacks. Stealth technology also has a secondary benefit of reducing the impact of aircraft noise and emissions on airport operations.

To supply affordable satellite-based communications, navigation, surveillance, and weather forecasting capabilities to both the military and the civilian sectors, inexpensive payloads and launchers would be required. For the military, on-demand launch capability would be needed to overwhelm the ability of an enemy

to destroy our satellites. For the civilian sector, industrial espionage may also require on-demand launch capabilities. Low-cost, launch-on-demand vehicles may utilize air-breathing propulsion while traveling through the oxygen-rich portion of the atmosphere. The key technology requirements include novel air-breathing propulsion devices such as gun-launched ramjets, scramjets, and ram accelerators; inexpensive expendable components; and technology to provide aircraft-like operations.

In the "Trading Places" scenario, Asia is the dominant economic power in a secure and stable middle-class world. The greatest capital resources and buying power reside in China, along with the greatest potential for market growth. The United States is relatively weak in its economic power. Threats to security or aggressive actions are not significant elements of this world. Although not active, China has military power that exceeds other nations' power. Governments of the world play a value-added role in society that is "allowed and controlled" by consumers.

In this world of global business and activity, China has become a significant marketplace and an economic power. This rapidly developed and still growing nation that is spread over a large area has bypassed the development of a surface transportation and communications infrastructure and now has a population that is predominantly middle class.

Consumers in this scenario are generally middle class and seek a quality of life that causes the population to be as geographically distributed as possible. They also respect and pursue environmental cleanliness. In addition, middle-class consumers experience a scarcity of leisure time. Nevertheless, Asians prefer to travel to the United States for vacation.

Business in this scenario is competitive globally, and international teams and partnerships are the norm. Asia has become the manufacturing center for products required to sustain both its own population and its economic strength through export.

Because China has bypassed the development of an extensive ground-based infrastructure, the transportation needs of its industries and middle-class consumers are mostly met by aviation. Regions rely almost entirely on air transportation systems that are tailored to serve their regional transportation needs. Industries provide "commute to work" services to geographically dispersed employees with privately owned and operated air transportation systems. Industries also use their transportation systems for the movement of raw and finished goods. Leisure travel by air includes point-to-point types of flights (i.e., Beijing to Jackson Hole, Wyoming) that must be comfortable and fun. The travel itself actually is considered part of the vacation's leisure time.

Both the teaming nature of business and the need to maintain an understanding of foreign markets creates intense demand for high-speed travel and communications that are used extensively.

This scenario provides an opportunity to start with a clean sheet of paper and rethink the ways the overall air transportation system can be optimized for specialized markets. The needs and opportunities that result are discussed below.

This somewhat new application of aeronautics would require air transportation systems that meet criteria different from those of the system that currently exists today.⁶ Privately or regionally owned air transportation systems would need to be tailored for both customers and for multiple uses within each customer's system. To support this need for flexibility, the system would need to be quickly reconfigured to accommodate multiple payloads, performance characteristics, and ground-based infrastructures (austere to sophisticated). Consequently, the design,

integration, and allocation of all system elements to be flexible, cost effective, and tailored for specific customer needs would require the "clean sheet of paper" approach. In addition, safety would need to be "designed" into the air transportation system rather than "inspected in" after the fact. This would allow the system to operate as safely or even more safely than today's air transportation system with less reliance on periodic inspections. Specifically, the system would contain a self-diagnosing capability that would terminate operations when unsafe conditions exist. Reliance on human skills and expertise would have to be minimized to ensure safe operation by regional groups and private individuals who were not career aviation experts.

Technical capabilities that support the need for dependable and safe air transportation systems would include smart systems and reconfigurable systems; onsite repairability that uses standard equipment; required skills training and repair support provided by communications capabilities that are similar to Internet⁷; immunity to most weather and runway conditions; and simple, affordable runway operations (e.g., short runways, inexpensive runways, or runways with multiple uses). Affordable and reconfigurable aircraft would require modular designs with snap-together, load-bearing disconnect-attach mechanisms and wireless, open-architecture avionics systems. Reconfiguration and safety requirements would be satisfied with smart systems, structures, and materials that detect breakdowns or problems and respond with autonomous adjustments that ensure continued safe operation or halt operations if safety cannot be assured.

Comfortable, fun, and affordable travel from locations throughout China directly to locations in the middle of the United States would create a need for very large, efficient aircraft. Providing desired and valuable leisure time for passengers while enroute would place less emphasis on aircraft speed and more emphasis on quiet, humidified, spacious aircraft interiors that would allow passenger activity. Entertainment on long flights would require extensive communications capabilities for the aircraft as well. The middle-class quality-of-life standards expected by Asian travelers in this scenario would create demands for safety, reliability, and environmental friendliness that equal or exceed today's aircraft performance in these areas.

The successful development of this aircraft would require significant improvements in airframe configurations, materials, systems architectures and technologies, and

approaches to communications technology. New structural materials that provide multiple features would help to achieve the required performance. This could be a material that provides structural support, and also acts as thermal and acoustic insulation for cabin areas, creates a flame barrier for the protection of passengers, and is immune to condensation and subsequent corrosion caused by increased cabin humidity.

An aircraft with similar levels of performance advancement in payload size, range, safety, reliability, and environmental friendliness also would be required to meet the cargo transport needs of this scenario's global marketplace.

To meet the travel demands of business people who require personal interaction with partners, customers, and clients around the globe, high-speed air travel capability would be needed in this scenario. The rapid movement of people or cargo is also important for resolving unplanned or emergency situations. Supersonic aircraft would not be optimized for leisure travel, but would need to be designed to minimize environmental impacts such as noise and emissions over all land masses.

The "Environmentally Challenged" world is one in which strict limitations are placed on worldwide carbon dioxide (CO₂) emissions because of conclusive evidence showing it harms the planet. Limitations and concerns are strongest in the developed nations; Europe is first to recognize the CO₂ problem. The United States, with high per capita energy consumption and emissions, is at a distinct disadvantage. Although the developing nations accept that CO₂ emissions are a problem, they place most of the blame on industrialized nations and are reluctant

to limit emissions if it hampers their own economic development and growth. Therefore, some developing nations seek to circumvent or evade emissions limitations. There is a system of caps on CO₂ emissions for each nation that is enforced by international organizations. In the United States, there is also a system of tradable pollution rights and very high taxes on carbon-based fuels.

The United States is a weak competitor in this scenario because of its high reliance on energy-intensive industries. The nation's large land area requires heavy use of transportation systems, which makes the United States a more intensive user of fossil fuels than most other nations. Because of high fuel prices, there is low growth in the demand for aerospace products and services. The developed world, including Europe, Japan, and the United States, imposes trade and other sanctions on lesser-developed, noncompliant nations in an attempt to force compliance with the CO₂ emission limits. This strategy raises tensions between the "have" and the "have-not" nations and has a destabilizing effect on global security.

The strong need to stop damaging the environment has captured public attention in the developed world. There are sporadic terrorist threats and attacks on intensive users of carbon fuels, such as the air transportation industry. The weak U.S. economy exacerbates domestic tensions with some of the nation's population looking to technology as a potential solution, whereas others view technology as a root cause of the problem.

The consumer prices for all modes of transportation are high because of high taxes on carbon fuels. In an attempt to reduce fuel consumption, airlines are shifting to less frequent service with larger aircraft and higher load factors. Aircraft also are now operated at optimized speeds (usually lower than current cruise speeds) and fly optimized flight paths so as to minimize fuel consumption. Firms also seek to reduce the energy input of producing goods and services by revamping production processes and by reducing the use of transportation for people and goods. As a result, both business and pleasure travel are reduced significantly.

The aerospace industry, facing a much lower demand for its products, aggressively seeks new markets. Distinct markets evolve for retrofit technology to reduce the fuel consumption and the emissions of existing commercial aircraft fleets without purchasing entirely new aircraft at greater expense. The U.S. aerospace industry is lagging compared with Europe's aerospace industry because it was late in increasing energy efficiency and reducing emissions in both its production processes and its product goods. There is a market demand for improved ATM to reduce fuel consumption as well as for sensors to detect pollution. U.S. firms are trying to exploit foreign markets where economic growth is stronger, but manufacturers and suppliers are forced increasingly to pursue alliances with foreign

companies so as to gain entry to these foreign markets. In addition, U.S. companies often bring only technology to the bargaining table because of the scarcity and cost of investment capital in the United States.

The U.S. market for military aeronautics products also is characterized by low growth in this scenario. Nevertheless, there is a heightened demand for monitoring and counterterrorism systems, including satellites and UAVs. There also is a growing demand for microvehicles (tens of kilograms) and systems that operate with extremely low fuel consumption. The U.S. military uses these systems to monitor other nations for reasons that include maintaining U.S. security, determining environmental compliance, and enhancing U.S. economic competitiveness.

In this scenario, the air transportation industry and the aerospace industry are particularly challenged because of their high-energy requirements. High fuel costs and financial incentives to reduce emissions would create the following needs:

• aircraft with reduced or zero CO₂ emissions

• the ability to place remote sensing systems for CO₂ monitoring and security into LEO and into the atmosphere on demand and at low cost

• ATM improvements to reduce fuel consumption

In addition, the high level of tension would create threats to civil aviation that would require improvements to the security of commercial aircraft. The technological implications and R&D needed to satisfy these needs are discussed below.

There are two research alternatives that could lead to the development of aircraft with either reduced or zero CO₂ emissions. The zero emissions objective would require the development of engines that burn nonfossil fuel, such as hydrogen-powered engines. It also would require that the energy used to produce hydrogen is not itself a source of CO₂ emissions. Nuclear energy or the hydroelectric generation of electric power are two possibilities. In addition to the hydrogen-fueled engine, the following capabilities and technologies also would be required to enable the operation of hydrogen-powered aircraft:

• low-weight cryogenic materials for hydrogen fuel tanks

• efficient means to produce slush hydrogen on or near airports

• safe means of handling hydrogen, including leak detection and mitigation

• efficient aircraft configurations to accommodate the size and location of hydrogen fuel tanks

Emissions reduction could be achieved by the development of technology to reduce significantly the fuel consumption of conventionally fueled aircraft. This alternative would have the advantage of being applicable to not only new production aircraft, but also would offer the potential for retrofit to the existing commercial aircraft fleet. Aerodynamic improvements to increase lift and reduce drag, such as microelectro-mechanical systems for flow control, would be one area of research to pursue. New, lighter "tailored" (designed at the molecular level) and "smart" (able to sense their own conditions) materials to reduce aircraft weight without compromising structural integrity would be another area of investigation. More fuel-efficient engines, which would require the development of higher-temperature materials, would be a third area. In addition, there would be a need to develop the means to remove CO₂ from conventional jet engine emissions. These could be biologically based systems or chemical processes that break down CO₂ into nonharmful components.⁸

In the "Environmentally Challenged" scenario, there would be a need to monitor compliance with emissions regulations and to counter selected security threats to the United States. These objectives would require the development of improved remote sensing systems that would operate from platforms within the Earth's atmosphere and in orbit. UAVs, which could carry sensor payloads within the Earth's atmosphere, would require improvements in data links, autonomous decision making, and related control technologies. Many of these sensors would be small and lightweight (on the order of tens of pounds), but would have the same functionality as larger sensors used today. Placing these sensors into Earth orbit on demand and at low cost would probably require technology developments for both payloads and launch vehicles.

This scenario, as mentioned previously, includes high fuel costs and limits on emissions. The development of improvements to ATM technology to enable the most fuel-efficient routing for aircraft could provide large benefits for commercial air carriers. To achieve this goal, technology would be required that improves the accuracy of sensors used for navigation and surveillance, improves the accuracy of

weather monitoring and weather information dissemination to aircraft, and improves overall security and integrity of the ATM system.

Technologies to improve the security of commercial aircraft operations would be required in this scenario. Requirements would include the adaptation of low observable and missile countermeasures technology to commercial aircraft without impacting negatively overall aircraft safety, cost, or performance. The structures and materials used in commercial aircraft also could be made more resistant to onboard bomb blasts or munitions from external sources. Finally, contraband detection systems could be integrated into the aircraft as a means of enhancing passenger safety and security.

Each need and opportunity mentioned in one or more of the scenarios presented above is included in Table 2-1. In many cases, a need or opportunity that was found to be important in one scenario also was important in another. However, the exact characteristics of each need or opportunity varied from one scenario to the other. Table 2-1 attempts to illustrate this by using generic language for the needs and opportunities listed in the far left-hand column, while using language in the remaining five columns that corresponds to the context for the need or opportunity within each scenario. A blank space in the table indicates that the need or opportunity in the far left-hand column was not considered in the given scenario.