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GAO/NSIAD-92-5 -- page 113
Chapter 9
Conclusions
The United States is ahead of Japan in hypersonic technology.
However, U.S. leadership and superiority in aeronautics face
increasing competition from Japanese efforts to develop
operational aerospace vehicle technologies. Japan has not
officially approved any plan to build an aerospace plane. The
United States also has not approved a plan to build an aerospace
plane. Although Japan does not have an established national
research and development program to build an aerospace plane,
Japanese government and industry are conducting feasibility
studies and developing the technologies needed for various
concepts of operational aerospace vehicles through various
programs to secure independent manned access to space, reduce the
cost of launching payloads into orbit, and ensure a competitive
role in future high-speed commercial transport markets.
Japan is conducting research and development on three different
but coordinated spaceplane programs. Japanese aerospace vehicle
development programs are essentially concept or system studies
and consist of fundamental research on enabling technologies.
Japan is coordinating various national aerospace vehicle
development programs in a step-by-step approach to achieve its
goal of demonstrating the technology for an air-breathing
single-stage-to-orbit aerospace plane.
Japan does not appear likely to develop and build an aerospace
plane by itself because of the extensive technology and funding
requirements and lack of adequate test facilities. Building any
future operational Japanese aerospace vehicle would require an
international effort.
Japan is the only other country besides the United States, the
Soviet Union, and France that is studying a single-stage-to-orbit
aerospace plane using scramjet air-breathing propulsion--the most
technologically challenging aerospace plane concept. The United
States, through the NASP Program, is advancing hypersonic
technology further than Japan. The United States is the only
country that has gone beyond the initial design phases and tested
major components of an air-breathing aerospace vehicle.
Although the Japanese are making a determined effort to challenge
U.S. superiority in hypersonics, the United States is ahead of
Japan in developing the three enabling technologies considered
critical for an aerospace plane: air-breathing propulsion,
advanced materials, and computational fluid dynamics. However,
Japan is making progress in the development of enabling
technologies, particularly in advanced air-breathing propulsion
and advanced materials.
GAO/NSIAD-92-5 -- page 130 Japan has conducted the necessary preliminary work on a wide variety of advanced propulsion systems for various aerospace plane concepts and other applications. Japan's approach is state of the art and the results are plausible and realistic. Also, Japan's research and development schedule is ambitious, but achievable. A Japanese systems study comparing engines concluded that the two best combined-cycle engine concepts are the air-turboramjet/scramjet/ rocket and the liquid air cycle engine/scramjet--the same two combined types of engines the United States determined were the best 30 years ago. Japan now has an engineering basis for selecting these two engines for further development. Moreover, Japanese duplication of U.S. engine tests and the ability to achieve the same results provide Japan with something it lacks: experience in hypersonics. Currently, Japanese advanced propulsion research and development is behind that of the United States, but they are making rapid progress in selected systems. The Japanese enjoy a high level of project consistency and continuous funding. Japan's aerospace plane development has been evolutionary in nature, while the U.S. program has placed greater emphasis on revolutionary advances achieved primarily through technological breakthroughs. Japan is developing several important aerospace plane propulsion systems that the United States has either abandoned or is not working on at the present time. These systems include the liquid air cycle engine, air-turboramjet experimental engine, and high-pressure expander-cycle engine. Japanese projects are generally smaller than those in the United States and focus on incremental advances in technology. The Japanese have good success in applying proven technology to new projects as seen in these engine programs. This evolutionary approach, coupled with an ability to obtain technology off the shelf from other countries, has resulted in relatively low development costs, steady progress, and enhanced reliability. Japan is clearly positioned to be a world leader in advanced propulsion technology for aerospace planes by the year 2000. Japan is pursuing an intensive and comprehensive research and development program in hypersonic propulsion. Although the United States is ahead of Japan in propulsion technology for a single-stage-to-orbit accelerator-type aerospace vehicle, Japan may be ahead of the United States in hypersonic propulsion technology for several other important applications, including two-stage-to-orbit space launch vehicles and high-speed commercial transport aircraft. Whereas the United States has
GAO/NSIAD-92-5 -- page 131 placed essentially all of its emphasis on a scramjet propulsion system for the X-30, Japan is building and testing components and complete engines using a number of propulsion cycles that are suitable for a variety of applications. No other country is pursuing such a comprehensive program in hypersonic propulsion. The Japanese are not only developing an air-turboramjet experimental engine but are building and testing a variety of other hypersonic propulsion concepts, including liquid air rockets, liquid air turboramjets, and scramjets. Japan may be in a position early in the 21st century to become the world leader in high-speed commercial transport aircraft at speeds above Mach 3. Although Japan may not be able to compete with the United States and Europe in the near-term for supersonic commercial transport aircraft, it may be very competitive in the Mach 3 and above transpacific hypersonic transport aircraft market. Japan is doing everything a prudent nation would do if that were its goal. Given this approach, Japan may be in a position to leapfrog over the U.S. aerospace industry in the next 5 to 10 years. Japan has active materials development programs and may lead the United States in selected aspects of materials research. Japan's capability to develop composite materials is increasing at a rate faster than that of the United States. However, the United States has the overall lead in the design and effective use of advanced composite materials in specific military applications. Critical technological advances are being made in carbon-fiber technology developed in Japan. Japan may be the world leader in advanced ceramic research and development. Primary opportunities for cooperation will occur with Japan in the area of fibers and ceramics. Japan is ahead of Europe and the Soviet Union and second only to the United States in materials and structures research and development. The United States is the world's leader in composite materials. However, the U.S. lead is being rapidly eroded by a combination of industrial technology transfer and strong research and development efforts by Japan and other countries. The use of composites is now well established in Japan and it may lead the United States in some commercial applications. Japan has also become an important composite material supplier to the United States. Some of the key advanced materials for a future Japanese spaceplane are being developed in nonaerospace industries. Relatively small levels of investment in the development of enabling technologies in Japan
GAO/NSIAD-92-5 -- page 132 (compared with investment levels in the United States) often lead to significant research and development being conducted. Technology developed by nonaerospace industry in Japan is applicable to developing and building a spaceplane. Many Japanese government and industry programs are long-term ventures geared to the future at the expense of short-term gains. The Japanese encourage and support parallel approaches to advanced materials research and technology. Requirements for Japanese government programs are usually set at a modest, realistic, and attainable level to maintain Japanese government and public support. Moreover, the goals are not driven by requirements for a specific system as seen in the United States. Also, direct Japanese government funding for new materials is quite small and focuses on areas of national interest. Japanese industry, driven by strong national unity, makes much larger contributions to the support of new materials research and technology. The United States currently has a commanding lead in computational fluid dynamics. However, strenuous efforts are being made in Japan to develop a competitive capability, since computational fluid dynamics is recognized by Japan (and worldwide) as a critical technology. Supercomputer hardware represents no problem for Japan, since three of the five supercomputer manufacturers in the world are Japanese. Growth in computational capability in Japan has been impressive, and Japan's national laboratories have the computing power to perform state-of-the-art computations on aircraft and propulsion systems. No Japanese aerospace vehicle program compares to the scope of the NASP Program in terms of the amount of funding or number and type of people working on the program. Levels of investment in air-breathing aerospace vehicle research and technological development efforts by Japanese government and industry to date are significantly less than U.S. government and industry investment in the NASP Program. Also, planned U.S. government and industry investment in the NASP Program are substantially greater than planned Japanese government and industry investment. According to foreign government officials and industry representatives, Japanese test facilities (such as wind tunnels and air-breathing propulsion test cells) are adequate for fundamental research and the current level of effort in Japan, but the facilities are not adequate for large-scale testing or development of an aerospace plane. The United States is
GAO/NSIAD-92-5 -- page 133 ahead in terms of facility size, productivity, and use of testing techniques. Japan's rate of progress in refurbishing and modifying old facilities and building new ones is significant. Japan wants to first raise its technology level to international standards before seeking international cooperation. Japanese government officials and industry representatives expressed interest in cooperating with the United States on the NASP Program but also had some serious reservations. These reservations are based, in part, on barriers that include Japan's lack of hypersonic experience, Japan's constitutional prohibitions against the military use of space, fundamental differences in U.S. and Japanese aerospace plane programs, and strict U.S. export controls on the transfer of technology. According to U.S. government and industry officials, areas in which Japanese technology might be incorporated in the NASP Program include advanced propulsion and advanced materials. Although Australia does not have an aerospace vehicle research and technological development program, Australian industry and universities are developing competence in selected subsystems and play a significant role in testing foreign aerospace vehicle concepts and components. Currently, the only two shock tunnel facilities in the world that can test real gas effects on space launch vehicles are located in Australia. This unique capability keeps Australia in the forefront of hypersonic testing. According to U.S. government and industry officials, the NASP Program could benefit from the use of Australian test facilities. Once larger U.S. and German shock tunnel facilities become operational, the Australian facilities could serve in a supporting role or provide a back-up capability. Australia's planned Cape York International Spaceport would be the world's first commercial facility designed to accommodate future horizontal takeoff and landing aerospace planes.
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