So interplanetary travel...cool yes?
How do we do it?
Shane Ross gives a compelling speech about the use of LaGrange points as entry and exit points into orbits of planetary bodies. The Interplanetary Transport Network
Essentially there are low energy paths that lead from Earth orbit to L1 or L2. There are then low energy paths that lead from L1 to the Earth-Sun LaGrange point called E1 or E2. And from there more low energy paths to the LaGrange points around other bodies in the solar system.
He uses the Genesis project as an example of very low energy orbits. The Genesis project used these low energy pathways to make its way from Earth to L2 and from there to E2 where it stayed and sampled the solar winds for 2 years.
It then used the reverse of those paths to make its way back to Earth again.
Genesis was able to do all this travel while using "...five hundredths of 1% of the fuel that it takes to get a rocket into Earth orbit." That is remarkable.
The major point of this whole speech was summed up early: Once you reach Earth's orbit you are halfway to anywhere.
Here is a little lighthearted graphic from the speech defining the low energy pathways as a Metro map.
Transit stop
Professor Ross argues that the Lunar L1 location become a gateway station.
It's the best location for a manned space station because: travel time is a matter of days from the Earth, launching craft and maintaining craft from that location is cheap, launching from L1 up to E1 or E2 is cheap and therefore exiting the local Earth system to head to other planets is cheap as well.
It becomes the closest rest stop on the interplanetary highway.
Can we get into orbit cheaply?
So then the remaining hurdle is getting into Earth orbit. If we can make that cheap then the entire process of interplanetary travel becomes inexpensive.
What technology are we working on right now that might lower the cost of getting payloads into orbit?
Space Elevator.
Does it feel like we are on the cusp of a convergence here? If we are able to tie these two sciences together, the engineering feat of a space elevator with the comprehensive knowledge of how to navigate the solar system's "currents", what will the bounds of our exploration be?
Cheap Planetary Travel
It would no longer require huge chemical rockets to get from Earth to Mars or Jupiter or anywhere for that matter. It would be like nudging a stick out into a stream and watching it float on down to the next stop. Only you would be able to nudge the stick back upstream as well, whenever you wanted.
Download and watch the video it's compelling.