In communication between distant space and earth, a light pipe might be a little cumbersome; hence it may prove necessary to set up an intermediate orbiting relay station that will, particularly in cases of poor weather, intercept the incoming laser beam and convert it to radio frequencies that can penetrate our atmosphere with greater reliability. Powering space-borne lasers will, of course, be a problem. Indeed one of the major unsolved problems in production of spacecraft and long-term satellites is the provision of an adequate supply of power. Fuel cells and solar cells have helped but do not give the whole answer.[17] One other approach has already been developed: a sun-pumped laser. Sunlight focused onto the side of the laser (see Figure 32) provides the pumping power, enabling the device to put out 1 watt of continuous infrared radiation, enough for special space applications. Descendents of this device could produce visible light if this is deemed desirable. Another approach, using _chemical lasers_, is even more intriguing and may have greater consequences. Chemical lasers will derive their energy from their internal chemistry rather than from the outside. A mixture of two chemicals may be all that is needed to initiate laser action aboard a spacecraft or satellite. (Chemical lasers also offer the promise of even greater concentrations of power than have been achieved heretofore, which may make them useful in plasma research.) With all these possibilities, it may still be that spacecraft will need more power than is available on board. The narrow beam of the laser offers one more fascinating possibility, especially in the case of satellites relatively near earth. The light of a laser might actually be used to beam energy to a receiver, either for immediate use or storage. It would then become possible to “refuel” satellites at will, giving them much greater capabilities. If available laser power is great enough, laser beams might even be used to push satellites back into their proper orbits when they begin to wander off course, as they almost invariably do after a while. [Illustration: Figure 32 _Artist’s rendering of sun-pumped laser as it would operate in space. The sun’s rays are collected by a parabolic reflector and are focused on the laser’s surface by two cylindrical mirrors._] Sun Parabolic Collector Hyperbolic-cylindric secondary mirror Semi-circular-cylindric tertiary mirror Laser beam A LASER IN YOUR FUTURE? Atomic energy, only a scientific dream a few short years ago, is now providing needed power in many parts of the world. In the same way, the laser, also an atomic phenomenon, has made its way out of the laboratory and into the fields of medicine, commerce, and industry. If it hasn’t touched your life as yet, you need only be patient. It will.