It may sound like a problem for the distant future, this pointing a radio beam at a planet, but it is no different than Galileo's attempts to see Jupiter through his Optik Glass. Of course, it has had refinements that have enabled men to make several hundred hours of exposure of a star on a photographic plate. So if men can maintain a telescope on a star, night after night, to build up a faint image, they can also maintain a beamed transmission wave on a planet. All you need is a place to stand; a firm, immobile platform. The three-mile-long, one-mile-diameter mass of Venus Equilateral offered such a platform. It rotated smoothly, and upon its 'business' end a hardened and highly polished set of rails maintained projectors that were pointed at the planets. These were parabolic reflectors that focused ultra-high-frequency waves into tight beams which were hurled at Mars, Terra, and Venus for communication. And because the beams were acted upon by all of the trivia in the Solar System, highly trained technicians stood their tricks at the beam controls, correcting by sensitive verniers any deviation of the beams. In fifty million miles, even the bending of electromagnetic waves by the Sun's mass had to be considered. Sunspots made known their presence. And the vagaries of land transmission were present in a hundred ways due to the distance and the necessity of concentrating every milliwatt of available power on the target. This problem of the _Empress of Kolain_ was different. Spaceships were invisible, therefore the beam-control man must sight on Mars and the mechanical cam would keep the ship in sight of the beam. The hours went past in a peculiar mixture of speed and slowness. On one hand the minutes sped by swiftly and fleetingly, each tick of the clock adding to the lost moments, never to be regained. Time, being precious, seemed to slip through their fingers like sifting sand. On the other hand, the time that must be spent in preparation of the equipment went slow. Always it was in the future, that time when their experiment must either prove a success or a failure. Always there was another hour of preparatory work before the parabolic reflector was mounted; and then another hour before it swung freely and perfectly in its new mounting. Then the minutes were spent in anticipation of the instant that the power stage of the transmitter was tested and the megawatts of ultra-high-frequency energy poured into the single rod that acted as a radiator. It was a singularly disappointing sight. The rod glowed not, and the reflector was the same as it was before the rod drew power. But the meters read and the generators moaned, and the pyrometers in the insulators mounted as the losses converted the small quantity of energy into heat. But the rod drew power, and the parabolic reflector beamed that power into a tight beam and hurled it out on a die-true line. Invisible power that could be used in communications.