By Bill Christensen
Gravitational corridors describe minimum energy pathways between objects in the solar system; they connect Lagrange points where gravitational forces balance out. They were first investigated by Jules-Henri Poincare, the French mathematician, in the 1890's.
These twisting, ever-changing pathways provide low speed but highly fuel efficient paths between planets and moons. They create what some call an Interplanetary Transport Network connecting all of the major bodies in the solar system.
These paths are reminiscent of that wonderful sf notion space-lanes. As far as I know, the first mention of this phrase was in Edmond Hamilton's 1928 classic Crashing Suns:
He had travelled the space-lanes of the solar system for the greater part of his life, and now all of his time-honored rules of interplanetary navigation had been upset by this new cruiser.
Just a generation later, Philip K. Dick borrowed this majestic term and used it to describe a harrowing daily commute back to Earth:
Commute ships roared on all sides, as Ed Morris made his way wearily home to Earth at the end of a long hard day at the office. The Ganymede-Terra lanes were choked with exhausted, grim-faced businessmen; Jupiter was in opposition to Earth and the trip was a good two hours.
In more modern sf movies, you might want to use a stellar cartography room, like the ones depicted in Star Trek: The Next Generation, to plot these routes.
Hardy spacefarers eager to ply the gravitational corridors between the Earth and Mars in real life should be prepared for a long voyage, though; it could take thousands of years. The best use for these "space-lanes" is as low-consumption routes between the moons of a planet like Jupiter.
One example of a real-life space voyage to use this method was the Genesis spacecraft launched in 2004 to capture solar wind particles and return with them to Earth.