Gliding, Gliding

The space ships of the future will not roar through the solar system, pushed by the blazing force of their atomic engines. Instead, they will coast in graceful curves, riding gravitational pulls as a glider rides the upward currents in the air. So thinks red-haired Professor (of astronomy) Samuel Herrick, 35, of the University of California at Los Angeles. Last week he was teaching an eight-man, two-girl class the delicate art of interplanetary gliding.

To clear the earth with speed to spare, says Professor Herrick, a space ship should start at 8 miles per second. Once clear, it becomes a miniature planet with an orbit of its own. The gravitation fields of surrounding bodies pull it hither & yon. By taking advantage of these pulls, the space navigator can guide his ship.

On a voyage to Venus, for example, the space ship would start at 8 miles per second in the direction opposite to the motion of the earth (see diagram) * Since the earth moves at 18 1/2 miles per second, the space ship's net forward motion would be 10 1/2 miles per second (18 1/2; minus 8 miles per sec.). This speed is too slow to

keep the glider in the earth's orbit, so the great pull of the sun would make it spiral inward toward the orbit of Venus.

The voyage would have to start at exactly the right moment, so that Venus would be on hand to meet the space ship. If the timing was wrong, the space ship would miss Venus, spiral toward the sun, and circle around it forever.

Out toward Mars. To reach Mars, the space ship would take off in the same direction as the earth's motion. Its increased speed (8 plus 18 1/2 equals 26 1/2 miles per sec.) would make it spiral outward toward the rendezvous.

In planning any voyage, the space navigator would have to allow for a host of "perturbations." Distant objects such as Neptune or comparatively small objects such as the moon might pull the ship off its course. A round-trip voyage would be ticklish. The ship would have to circle the objective planet and come back just in time to meet the earth. A miss would mean a plunge toward the sun.

In pure space-gliding, only cheaters use power. But Professor Herrick believes that real space ships will use their power in spurts to correct their courses and climb steep gravitational grades. He does not hanker to make any voyages himself but he has thought deeply on the subject. "On a voyage to Venus," he says, "we should take both sexes, if we plan to do any colonizing."

* The diagram is schematic, neither complete nor accurate by astronomers' exacting standards.

This file is automatically generated by a robot program, so reader's discretion is required.