NASA rocket scientists have used the gravitational pull of one planet to “slingshot” space craft toward another planet. This method causes acceleration without additional fuel use. What if we could set up a system where craft were in (almost) perpetual motion between Earth and Mars, using each planet’s gravity to sling it toward the other? Such a trajectory is available, thanks to the work of Apollo astronaut Buzz Aldrin. The orbit is called the Aldrin Cycler. Unmanned explorers and astronauts could catch a cycler every 26 months and ride to Mars (or back) using a small fraction of the fuel that would be needed for a conventional mission. The cycler orbit simulation above can be seen in motion at Damn Interesting. Link
NASA rocket scientists have used the gravitational pull of one planet to “slingshot” space craft toward another planet. This method causes acceleration without additional fuel use. What if we could set up a system where craft were in (almost) perpetual motion between Earth and Mars, using each planet’s gravity to sling it toward the other? Such a trajectory is available, thanks to the work of Apollo astronaut Buzz Aldrin. The orbit is called the Aldrin Cycler. Unmanned explorers and astronauts could catch a cycler every 26 months and ride to Mars (or back) using a small fraction of the fuel that would be needed for a conventional mission. The cycler orbit simulation above can be seen in motion at Damn Interesting. Link
Unfortunately, like Space Elevators, Pinwheels, and other elegant solutions, the initial outlay is way too big and thus it won't happen in our lifetimes. Once we find a compelling financial reason to go to Mars, maybe, but even then...