Hmm, they said heliocentric several times. But it’s a cool orbit no matter how you slice the the pork chop. Pretty sure this is intended to be similar to a “mars cycler” orbit. A “mars cycler” is an interplanetary space station which follows a sort of transfer orbit between earth and mars. This provides a cushy radiation shielded environment for interplanetary travelers and economizes on propulsion by leveraging gravity assist. IIRC some guy named Aldrin came up the gist of the design.