Interplanetary Flights: Low Thrusts for High Goals

Abstract

The achievements of the human race in the conquest of cosmic space have been enormous. During an interval of 12 years, between 1957 and 1969, we went from the launching of the first artificial satellite to the landing of the first mission to the Moon. But our greatest dream — missions to other planets — still remains to be fulfilled. Carrying out such missions is a difficult task, which can be accomplished by various means. Perhaps spaceships will be assembled and their engines fueled in an orbit around the Earth. Or perhaps spaceships will depart from such an orbit by using not chemically-fueled jet engines, but low-thrust engines — for instance;ion or plasma engines that are being designed in many laboratories and were already mentioned in the 7th essay. The maximal acceleration that a spaceship equipped with such engines may attain is of only several mm/sec^t, but acting unceasingly over the entire duration of the flight (for several months!), even such a low thrust gives ample capabilities for maneuvering the spaceship in cosmic space. One can picture how such a spaceship, moving along an unwinding spiral trajectory around the Earth, attains escape velocity and, free to move in space, embarks upon a course to Mars. In the vicinity of Mars the low-thrust engines gradually slow the spaceship to parabolic (relative to Mars) velocity; then the spaceship engages in a spiral trajectory which leads to the final orbit around Mars and parks on it until the expedition lands on the planet’s surface using a landing spacecraft and then returns.

We were but prisoners on a humble planet And how many times, in the countless succession of years, Earth’s steady gaze into the dark expanse Followed with longing the motion of the spheres!

V. Bryusov, Son of Earth

We must carry to other planets The gospel of our little Earth!

V. Bryusov, Child Dreams