DEVELOPING THE SPACE FRONTIER
The late Adlai Stevenson II captured the world's imagination in 1965 with his concept of "spaceship Earth" -- an isolated ark, brimming with life, drifting through space.
But his contemporary, Krafft A. Ehricke, never did like the term.
One of the most farsighted of the German rocket scientists who emigrated to the United States, he insisted, "We must realize that Earth is not, as some call it, a 'spaceship' traveling in isolation. Earth is a passenger ship, the only passenger ship, in the convoy of our star. The rest of the planets are freighters." He maintained that "these resources are for us to use, after Earth has hatched us to the point where we have the intelligence and the means to gain partial independence from our planet -- and when the time has come to convert our Earth from an all-supplying womb into a home for the long future of the human race."
Ehricke has proved a prophet to be reckoned with. He foresaw the space shuttle in 1956. While Apollo astronauts were gearing up to explore the moon, he was developing a concept for an orbiting space observatory that became Skylab. He is known as the "father" of the Atlas-Centaur multistage rocket that was the workhorse of early US space exploration.
Now, with the advent of the US space shuttle and the imminent prospect of a permanent Soviet manned space station, the early phases of his larger dream should soon begin to be realized. He called it "the extraterrestrial imperative." Space planners call it the industrialization of space. Some of them say it already has begun with the maturing of satellite-based communications, a billion-dollar industry that is expected to expand substantially when larger structures are built in orbit with the help of the shuttle.
Even the dream of mining the moon, asteroids, and other planets, which a number of space planners now envision in the indefinite future, has relevance today in giving an overall sense of direction. Jesco von Puttkamer, a space industry planner with the National Aeronautics and Space Administration (NASA), explains:
"By establishing a 'relevance tree' between far-future dreams and near-term, pragmatic realities, we are in a better position to identify major steppingstones that will bring contemporary benefits . . . This approach brings 'dreams' into the realm of strategic thinking. It allows us to give a larger purpose to our near-term 'tactical' and pragmatic activities . . . and improve our ability to avoid dead-end 'branches' in our major planning decisions for space industrialization."
The initial steppingstones fall into two categories -- materials processing and space engineering, meaning the installation, construction, and maintainance of orbiting structures. NASA is preparing for both types of activity. The Soviets say they are too, although their plans are not clear to Western observers.
Materials processing is a catch-all term for a variety of manufacturing possibilities. The point is to take advantage of what the orbital environment uniquely offers -- a high vacuum and the absence of any significant gravitational forces (weightlessness).
In orbit, gravitational effects such as buoyancy, differential settling and sedimentation, or convection, which impede the preparation of special materials on Earth, do not operate. Instead, diffusion and surface tension (the force that makes water drops pull together into spheres when weightless) become important. Preparation of more uniform materials that include different substances should be possible. Large pure crystals of important materials can be grown. Alloys of metals that don't mix well on Earth can be prepared. Living cells and proteins can be separated better by electrical forces, yielding purer outputs of important biochemicals.
These possibilities already have been explored to some extent in American Skylab and Soviet Salyut experiments, in the joint US-USSR spaceflight, and during brief unmanned rocket flights.
For example, without gravity, skin tension becomes an important force. It should be possible to make castings using only a thin oxide skin, like the skin on fresh paint, as a mold.
ERNO, a member of the VFW-Fokker group in West Germany, has demonstrated this on a rocket flight with the melting and cooling of a turbine blade made of a special alloy called IN 100. An aluminum oxide ceramic coating only one-tenth of a millimeter thick contained the molten blade quite well. The ability to cast this particular kind of turbine blade in this manner could greatly extend its life. And at $5,000 a kilogram for blade material, substantial savings could be made.
Japan and a number of European countries, especially West Germany, are highly interested in materials processing in space. They have reserved shuttle space for their experiments. Many such tests will also be made in the Spacelab -- a capsule where experimenters can work, which is Western Europe's contribution to the shuttle system.
The Soviets, too, have expressed much interest in this field. They have spoken of developing automated orbiting factories as a natural development of Salyut 6 experiments. These would be unmanned space stations to be serviced periodically by cosmonauts.
In the United States, however, the concept has had a mixed reception. In 1978 a committee of the National Academy of Sciences downgraded it as an impractical dream. It saw few jobs for space processing that could not be done better on the ground, using skillful engineering to overcome gravity-related problems. It observed that ". . . the space environment usually contributes at least as many problems as it solves."
Supporters of the concept noted that the academy committee was lacking in aerospace experts who were closer to planning in this field than many of the committee members. This gave the report an air of old-guard conservatism, they argued.
The General Accounting Office (GAO) apparently thought so too. Last year, it issued a study of its own that called NASA's materials processing program "an example of a federally supported research effort that we believe could ultimately benefit the economy through the application of new knowledge, and eventually in space." Noting that "according to some materials scientists, enough of the right kinds of research could create a knowledge explosion," it warned that the US was in danger of losing the benefits of this to competitors because of niggardly funding of the NASA work.
The report noted the interest of the Europeans and added pointedly, "The capabilities demonstrated aboard the USSR's Salyut 6 . . . and the large number of top scientists committed to materials research leave no doubt that major technological achievements can be anticipated by Communist-bloc countries."
GAO urged doubling or tripling NASA's budget for this field. The Carter administration's response was to raise it from $21.7 million in fiscal 1981 to a proposed $32.1 million for fiscal 1982. At this writing, it was unknown whether the Reagan administration would let that increase stand.
Meanwhile, NASA has been encouraging industrial participation in the program in a variety of ways, including provision for proprietary packages to be flown on missions --packages whose contents and experimental results would be the property of their sponsors.
The least costly of these are called "getaway specials." They would be contained in simple canisters of from 2.5- to 10-foot capacity and cost $3,000 to $10,000 to send on a mission. They are literally "kid stuff" in the best sense of the term. Schools, civic groups, and others have been raising money to give hometown youngsters a crack at one of the specials. Over 300 have been reserved so far. University of Utah students, for example, plan to test a solar sail, a propulsion system using light pressure from the sun that NASA seems to have abandoned. Prof. Rex Megill of Utah State has said he "wouldn't be at all surprised if some of these kids came up with important results."
Meanwhile, in the other major space industrial field, NASA has big plans and is waiting to see how many can be fitted into its new budget.
For a number of years, and with the help of several industrial contractors, NASA has been studying how to build big in space. Lightweight yet sturdy beams have been developed that can fold up for transport by shuttle and unfold in orbit. Designs for so-called beam machines that can extrude lightweight girders also have been worked out. Astronauts have experimented with assembly of such beams under simulated weightless conditions in a water tank.
NASA planners have in mind large structures ranging up to several thousand feet in a typical dimension, and eventually perhaps reaching one or more miles. Engineering on such a scale involves techniques of assembly and maintenance as well as beams and trusses. Many operations could be automated. Others would require assembly by astronauts, working either in space suits or special small self-propelled vehicles. A work platform, resembling the cherry pickers used by tree surgeons, might be deployed from the shuttle.
NASA itself expects to be a relatively early user of orbital structures. Plans call for assembling a 25-kilowatt auxiliary solar power plant for use with the shuttle and for deploying a larger power plant later. Both NASA and the Department of Defense are interested in orbiting large antennas for communications and scientific purposes.
One important structure that might be orbited in this decade is a geosynchronous platform. Geosynchronous means orbiting at such a speed that the spacecraft remains over a given spot on the equator as the Earth itself turns. This orbit, 22,300 miles high, is a favored location for communications and weather satellites. In fact, it now is so crowded it is difficult to find space for more communications satellites to serve the US without interfering with one another. A large platform placed in this orbit could accommodate enough equipment to take over the job of several communications satellites and carry other payloads as well.
A concept for such a platform being developed for NASA by the General Dynamics Corporation would have a mass of 10,000 pounds. This is well within the 65,000-pound capacity of the shuttle and could be carried up on a single flight. Placed in a relatively low orbit, an auxiliary rocket would boost it to its operational height. It would have 8 kilowatts of power and four antennas ranging from about 13 to 47 feet across, a smaller antenna for communicating with other satellites, and some other experimental payloads.
To give an idea of the kind of service a large communications satellite could provide, Jesco von Puttkamer has pointed out that a single 220-foot diameter system could give 25 million people two-way voice and data communications. They would need little more than a communicator the size of a wristwatch. A global system of this type could put people in touch with each other from any point in the world to any other point directly. Although this may sound science-fictional, it should be easy for electronics manufacturers to provide inexpensive communicators once the satellite itself is in place.
Eventually, probably within this century if not this decade, the evolution of large space structure technology should lead naturally to a permanent manned space station. The Soviets have been quite specific in saying this is their aim , but considerably less specific in detailing just when and how they might do it. NASA, as of now, has no authorized space station program beyond some design studies. And, given the present budget-cutting mood in Washington, it is hard to forecast when such an ambitious project might be authorized.
Meanwhile, as the GAO study pointed out in regard to materials processing, there is a new frontier for industrialization opening in Earth orbit. It is virtually impossible to anticipate the host of new opportunities that will evolve. This is just what Krafft Ehricke envisioned when he saw space industrialization as a creative response to so-called "limits to growth" on Earth. Of those who would devalue such an opportunity, he said:
"The naysayers are the polluters of our future. They deny vital options to future generations."