A variety of interplanetary probes can be supported within the backbone system. These are placed into interplanetary Hohmann transfer (or gravity assisted) orbit using ion propulsion (the ion engines being recovered). They use aerocapture at the target planet, except at Mercury and Pluto. This might involve multi-loop strategies and include deployment of moon subprobes. Subprobes can use a main orbiter as a relay for communication.

For the inner planets the backbone system can be used. For example, a large ground observing telescope could be put in Mars orbit, even polar.

For the outer planets power is as usual a thorny issue, and arises even for the outbound flight. One solution is a small nuclear reactor, a heat engine, and a battery, on the main probe; and batteries on the subprobes. This uses less nuclear material than solutions not involving heat engines. The required heat engine lifetime is small. The possibility of hydraulic suspension in a liquid metal Rankine engine should be considered.

Safety considerations for the reactor can be addressed as follows. The nuclear fuel is removed from high strength containers only once it is in solar orbit; and only then placed in the reactor, which in turn has sophisticated safety systems. "Hot" objects always end up in orbit around an outer planet, or in interstellar trajectories.

Sample return might be an unnecessary luxury, given the equipment which can be sent to the planet. Strategies for accomplishing this can be considered, though. These might involve using the power of the central node power plant to put gathered samples into interplanetary orbit using an ion thruster (gathering might involve rockets and battery powered ion thrusters). The interplanetary orbit is "Earth crossing", and the samples are retrieved by SIP.