Authentic Science Fiction Monthly, No. 65 — page 26: what you’re looking at

Machine-transcribed from the original scan — historical spelling and the odd misread are preserved.

AUTHENTiC SCIENCE FICTION tail streams away from the Sun because of solar radiation pressure even when the comet is on the outward leg of its orbit. The force exerted by sun- light on a body is proportional to the cross-sectional area of -the body and the inverse square of the distance of the body from the Sun, so that the ratio of radiation force to gravitational force is a con- stant for a body of fixed mass and cross-sectional area no matter where it is in the solar system. The cross-sectional area of a spherical body varies as the square of its radius, while its mass varies as the cube of the radius. Other things being equal, therefore, the ratio of mass to cross- sectional area decreases as the radius decreases. Thus, for very small bodies, the force of repulsion due to radiation pressure can be greater than the force of gravitational attraction and the particle moves away from the Sun. An orbit-to-orbit spaceship using this idea would have large sails outspread to catch the ‘“‘wind”’ of radiation pour- ing out from the Sun. If the area of the sails was great enough, and the total mass of ship and sails small enough, then the sailing spaceship would spiral out from the Earth’s orbit to the Martian orbit. Whether such a delight- ful idea is practical or not is a problem we will leave till another time. In any event, we see that current astronautical opinion is that the voyage to the Moon can be accomplished by true spaceships built in the circum-Earth orbit and propelled by conventional low-power chemical rockets or by atomic rockets using an inert working fluid or powering an ion drive. The duration of the voyage will be five days, at the end of which time man will set foot on the Earth’s satellite for the first time. comicldooks.com a ne