If you look online you will find many sources on this subject. One of the leading experts on this subject is Martin Lo , who appears in the movie. In summary the theory redefines the way we look at orbits around planets. Unlike the typical circular orbits around each plants having their own space and not really intersecting, the IPS is an intrict set of routes or tubes between all planets as shown in the artist illustration.
This theory has been used in practice in the Genesis Project in early 2000, which mission was to collect solar wind samples and you can find more on the IPS and space from the following two example links.
link 1
link 2
Despite the technical difficulties in understanding the whole thing, I see it as an interesting turning point in space travel, and maybe also time travel.
Purgatorian Post #967
