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KEY CONSIDERATIONS IN FUTURE SPACE PROGRAMS
The American Institute of Aeronautics and Astronautics is the technical society whose membership of 25,000 engineers, scientists, and students represent all the disciplines of the aerospace profession. Clearly, space is our business. We have frequently presented testimony on future space programs before subcommittees of this Committee and elsewhere, and we appreciate this further opportunity to express our views to the full Committee on this 20th anniversary of our nation's first successful space flight.
In the past two decades, the U. S. space program has come nearly full circle. Our initial efforts were of necessity exploratory, seeking to develop the technology and capability needed for more ambitious future endeavors. The manned lunar missions demonstrated how successfully we accomplished that phase. In the decade of the 1970's, we have turned more and more to the utilization of our space capabilities to improve the quality of life here on Earth. Applications to communications, meteorology, resource detection and education, and the development of new scientific knowledge about the Earth, Sun, solar system, and the stars have become the principal focus of space activities.
Now, we are preparing to begin again the process of maturing a whole new gamut of capabilities. The advent of the space shuttle both
enlarges our ability to perform applications-oriented missions and opens news vistas of what we can accomplish in space. Other witnesses at these hearings will describe some of these prospective new missions, many of which are described in previous AIAA publications which have been placed in the records of this Committee's activities. Many AIAA
members believe that whereas we are devoting adequate attention to
the applications (including scientific exploration)
certainly both excellent and necessary we are not preparing properly for the potential expansion of space activities which is made possible by the introduction of reusable space transportation systems. These concerns were expressed by members of our Technical Committee on Space Systems, and endorsed by our Board of Directors, in our critique of NASA's "Outlook for Space" study several years ago. Unfortunately,
they are still applicable today.
should not be allowed to
Our concerns fall into two categories: technical and managerial. We can dispose of the managerial concern quickly: it is simply that one of NASA's basic purposes research and development of new space technologies, systems, and capabilities become secondary to the operation of applications programs, with the consequent deemphasis on advanced programs designed to support future needs. We recognize, of course, the need for someone to operate our space systems Earth resources, space transportation, astronomical and scientific satellites, and so on but we should not foreclose
on our preparation for the future in order to do so.
We believe this Committee should initiate the exploration of the various approaches to implementing the operational aspects of space activities. Possible options are to expand NASA's charter, as was suggested by former AIAA President Daniel Fink in Astronautics & Aeronautics back in 1973; to set up new federal agencies; to transfer operational activities to an existing cognizant federal agency (as was done with weather satellite operations); to encourage private industry to take over operations, as was the case with communications satellites; or, when operations have a multinational application, to
organize an international consortium such as Intelsat. Even the shuttle, once it has reached operational status, should perhaps be operated by an entity more like a commercial airline. It is a transportation system, and NASA's job should be improving it and developing follow-on capability, not selling tickets or performing engine and airframe maintenance. The forthcoming competition of the
ESA Ariane launch vehicle for shuttle payloads emphasizes the need for careful thought on this question.
I would like to turn now to our most serious concern: the lack of technology programs directed at the fulfillment of the promise of space. Note that in concentrating on technologies, I do not mean to ignore the important task of defining new space missions for the future. However, there are a number of AIAA publications already in the record of this Committee and its Subcommittees which suggest new missions; many more are suggested by other witnesses at these hearings. But without the basic technological capabilities, none of these new missions will be viable.
Although the general attitude of emphasing applications to the detriment of future capability development prevails almost across the board at NASA, I will limit myself in this paper to only three examples of technologies which we believe are essential to our future in space, and which are not now receiving adequate attention. These three areas are propulsion, power, and large space structures.
The lack of a sound NASA rocket propulsion technology program, identified over three years ago by NASA's own Research and Technology Advisory Council, is already beginning to affect plans for proper
Many of the shuttle's prospective customers re
quire higher energy orbits than the shuttle orbiter can provide; especially geosynchronous orbits and Earth-escape trajectories. The projected interim upper stage and spin-stabilized upper stage do not begin to meet the capabilities required of a standardized orbital transfer vehicle and the principal lack is that of a good, advanced liquid-propellant rocket engine, which in the long run could reduce transportation costs and make the shuttle system economically more attractive. As a consequence, the shuttle may suffer a serious loss of potential business; e.g., to the ESA Ariane launch vehicle I
But the lack of an active and viable rocket propulsion technology program has even more serious consequences: a loss of intrinsic capability in this area. Our impressive past successes in space were in no small measure the result of several decades of building propulsion capability: test facilities, production facilities, support facilities, propulsion hardware, and, most important, people. NASA's cadre of experienced rocket propulsion personnel is dwindling rapidly, (as are key NASA cadres in other space technologies). There are no
new people coming along to replace them, because there are few programs for them to work on. The industry cannot develop new engines on their own; such high-risk efforts classically are performed by government laboratories.
And because virtually all space activities require propulsion, the absence of a strong, continuing program of research and technology implies an approaching obsolescence in our entire future space program, which is what these hearings are, hopefully, aimed at
The weakness of NASA's space power technology program will not be felt quite so soon in propulsion, but it could turn out to be
more serious a limitation in the long run. It is already evident that even the shuttle's fuel-cell powerplant, basically an Apollo derivative, will limit several projected Spacelab and other missions. And fuel cells are only short-term power sources. The next commercial phase of space activity generally recognized as the development of new and improved communications functions will require substantially greater power than the maximum of a few kilowatts now available from current photovoltaic power supplies. Projections to more ambitious programs in the industrialization of space, which I will touch on later, identify on-board electric power as one of the principal limitations. Photovoltaic supplies might be able to be used up to perhaps 50 kW, but higher power levels, such as are needed, for example, by the space-based propellant processing system which General Dynamics has suggested as a means for expanding shuttle capabilities, probably require more compact systems. Yet, aside from one extremely high-risk 400 kWe heat-pipe-cooled reacter design employing even higher-risk thermionic converters, there are no nuclear reacter space power sources under active consideration today. And even the high-risk 400 kWe system study does not include a reacter technology development effort.
The final point of technical concern I wish to bring to your attention is the lack of a responsible, coherent research and technology program aimed at understanding the fabrication, deployment, utilization, evaluation, and maintenance of large structures in space. The preponderance of space activities which have been suggested for the late 1980's and 1990's will require not only the higher levels of onboard power I have already mentioned, but also the use of much larger