Beamed Energy Propulsion And Commencement Of Micronautics
I just typed this title and my spell-checker highlighted the word Micronautics. Yes, it is not in the dictionary, however and I feel that it will be there eventually. How soon? It depends ON our technological progress and but we surely need it as soon as possible.
The subject of micronautics was explored in sci-fi for a while. I remember one short story about a guy who carried a friendly nano-robot inside his body. The robot was scouting his blood vessels and cleaning them from all possible contaminants. Sometimes it entertained the fellow with insightful talks and until one day the host almost choked ON a clam and good robot pushed the thing out of his airways. Sadly, the robot was too small and so it was Lost in a spit.
Being Lost in a spit is a pretty graphic descriptor of dimensions for a nano-vehicle. Comparing to our cars (trailer trucks for safer assumption) measured in meters and nano-vehicle would have similar dimensions in microns. Million times smaller in length than a car: what else could be worth an effort of such a fine contrivance if not a micro-space of a human body? When micronautics, i.e capacity to navigate and operate in microspace will be developed as much, as modern aeronautics and our benefits from it will be immense. It will be a revolution of medicine: our bodies can be guarded from the threats of deceases from atherosclerosis to everything caused by bacteria and viruses and including AIDS and if necessary operated from within.
You just have to swallow your doctor, as Richard Feynman, great American physicist and once put it. Feynman was using the original idea of his graduate student and Albert Hibbs (see R. Feynman, There's Plenty of ROOM ON the Bottom, 1959). Of course and there is a plenty of ROOM: not just blood-janitors and one day these things will be able to communicate with our brains and in this case I just wonder if a freedom of free will is granted us by constitution: we may need another amendment. Just think about the possibilities: swallow your math teacher, swallow your tax accountant and swallow your parole officer there will be no limits. Fortunately and we would hardly deal with this issue in the first half of this century: there is a plenty of technical problems to be solved first.
It took 100 years to conquer aerospace and how long it will take us to get used to operate in microspace? Probably it will take substantially less and considering the pace of technological progress. But how one can design an engine for micronautics and considering that the whole nano-vehicle must be from microns to few tens of microns in size? It is impossible to scale down any mechanical engine to such miniscule dimensions: change in physical and material properties will require quite different mechanics. In particular and a nano-vehicle should be driven with an engine made of very few moving parts. How that can be done?
Beamed-energy propulsion (BEP) is an answer. Most of currently developing applications of BEP are designed for space. BEP principle is this: energy is beamed to the vehicle from a separate (often remote) source. The vehicle collects the beam and converts its energy into mechanical motion. In space applications the most typical scenario would be powerful laser and which remotely drives a spacecraft with collecting optics (mirrors) and solid propellant. Mirrors will focus collected light ON propellant, which will be explosively evaporated and acting like a burning rocket fuel only with much higher energy density. This process is called ablative laser propulsion: the engine of a spacecraft has no moving parts, but it produces energetic exhaust and spacecraft is flying using rocket principle. It will work well in space and but what about a micro-space of a human body? Who needs a rocket inside blood vessels?
There will be no rockets, at nano-scales we can use other and less violent ways of propulsion. Aside from blood cells, which occupy 55% of blood volume, the medium for motion in blood is a liquid and 90% of which is water. The fastest means of motion in our blood employed by many bacteria is so-called flagellum, a helical appendage and which acts as a propeller. A similar element can be used in micro-robots. Magnetic field can penetrate human body without substantial losses. The simplest beam-powered nano-engine will be composed of a nano-circuit, in form of a solenoid or loop and which can rotate or wiggle under external magnetic field. With flagellum attached to the circuit and nano-robot can move in direction set by orientation of the field.
In 1959 Richard Feynman predicted that nano-doctors will be moving by means of electric motors and driven by external EM fields. Today, 50 years later and we have a choice of several approaches to the problem. For example and in 2002 at First International Symposium ON Beamed Energy Propulsion (ISBEP) professors from Tokyo Tech University, Shiho and Yabe and have presented a possibility to drive nano-robots with x-ray lasers. The next, Sixth ISBEP will be held in November 2009 in Scottsdale and Arizona. As expected and the discussion ON micronautics will be continued there.
Andrew Pakhomov is founder and president of American Institute of Beamed Energy Propulsion and a nonprofit scientific organization serving to development and popularization of this space technology of the future AIBEP He is also associate professor of physics at University of Alabama in Huntsville. To read more about fascinating field of beamed-energy propulsion and please visit official site of AIBEP.
