Review: future space technologies
by Taylor Dinerman
|Bekey lays out a few of what he calls, “High Leverage Principles,” built around the notion, “Don’t fight the space environment—use it to advantage.”|
“The membrane is constructed as a sandwich of two piezoelectric materials, polarized in opposite directions and constituting a bimorph.” Using a scanning electron gun, similar to what exists in every old fashioned TV set, the aperture (or antenna) can be shaped and reshaped, according to the needs of the moment, for example, after it is warped by a particularly strong solar storm.
One of the military uses for such structures includes laser designation of targets from orbit. Such a system could be part of a precision strike system that would allow small targets to be hit from the continental United States without any US personnel on the ground, or even inside the airspace of the enemies’ nations. Other applications include mine detection, night illumination, brute force jamming and a long-dwell imager with a 20-centimeter resolution.
Bekey is well known as an advocate of tethers, which take advantage of Earth’s electromagnetic field to generate power for multiple applications. He asks “…why they have not yet been applied seriously in space…” A concept that can theoretically solve as many space problems as the tether should be in widespread use. According to one expert, “there has not yet been a 100% successful tether experiment in space.” That may be so, but the potential for propellantless propulsion is so great, that no major space program can afford to ignore its long-term value.
Another technology that the author has been promoting for a long time is what he calls “buckytubes,” but is better known as carbon nanotubes. The potential for this new class of materials is well known—a strength-to-weight ratio more than 600 times that of high-strength steel. Millions, perhaps billions, of dollars have been spent on nanotube research over the last decade with few results. The potential revolutionary impact of such materials on the weight and strength of air and spacecraft, not to mention things like cars, trucks, and military vehicles, is enormous. As long as scientists can show that they are making progress then, no doubt, funding will continue to flow towards these efforts.
Using carbon nanotubes, the mass fraction problem that has plagued all efforts to build a fully reusable launch vehicle, can be easily solved. Outside of low earth orbit, spacecraft made using nanotubes as part of their structure could be propelled around the solar system far easier than older space vehicles made of metal alloys or carbon composites. Indeed, the claims made for this technology sometimes make it sound like the legendary aerospace material “unobtainium.” Yet, so far the evidence shows that these amazing strands can be built. Today, they may be no longer than an inch or two but, if they can be made that long, then it is only a matter of time and effort before they can be made long enough to be truly useful.
Bekey believes that weight will become almost irrelevant as a cost factor for large aperture spacecraft due to the use of “gossamer structures construction as well as the use of buckytubes.” These new materials will revolutionize the design of other types of spacecraft. Once weight is no longer a driving factor, other priorities, such as safety and reliability, will become more important.
|The most important message to come out of this ground-breaking study is that, “Extrapolation of today’s techniques won’t get us there.”|
The military implications of these new technologies are also addressed by Bekey. Some of his points include: “Global force projection from space will be ubiquitous and devastatingly effective.” “Complete situational awareness will exist from GEO at theater to global scales,” and he warns, “The United States will not have decisive technological advantage over others.” This last point is disturbingly accurate. If the US does not invest in these and other technologies its global role will, over time, diminish.
The most important message to come out of this ground-breaking study is that, “Extrapolation of today’s techniques won’t get us there.” The normal step-by-step process has given us highly refined versions of space launch systems that were first used almost half a century ago, such as Atlas and Delta. The advanced concepts advocated by Bekey are all high-risk ventures. Investors and/or taxpayers could waste hundreds of millions or perhaps billions of dollars trying to move them from dream to reality. However, if even only a few of these ideas become operational within the next twenty to thirty years, the payoff will be immense. Hundreds of billions in new business will be generated and America’s ability to enforce peace will be maintained and enhanced.
Few technological visionaries have combined Bekey’s solid technical background and his broad view of both the civilian and military aspects of the future. His impressive understanding of materials, communication systems, earth and space science, launch vehicles, and microwave applications is probably unmatched by any other space expert. His understanding of Washington’s byzantine budget politics is pretty fair. If he fails to examine the societal implications of some of the projects he describes, there is nothing wrong with that. He could just write another book.