# Mathematical Digest

### Short Summaries of Articles about Mathematics

in the Popular Press

"Pulling Power", by Ian Stewart. *New Scientist,* 28 November 1998, pages38-41.

In space, the most efficient way to travel from one point to another is not always a straight line. Curved paths which take advantage of the gravitational pull of nearby objects can require less fuel for navigation. Little fuel is needed to keep communications satellites moving in regular orbital paths about the earth, for example. When an object, such as a satellite, is subject to the gravitational pull of two or more nearby bodies, the resulting orbital paths are not always so regular. This article explains how engineers use chaos theory to send satellites into bizarre orbital patterns -- and move them large distances with little fuel.

*--- Elizabeth Moisan*