Political Units In The Solar System

There are two interplanetary political units in the Solar System in the twenty third century of Poul Anderson's Psychotechnic History:

the Solar Union, an alliance between the governments of Earth, Mars and Venus, rules the inner planets and the asteroid belt;

the Jovian Republic, with its government on Ganymede, rules the Jovian moons, in particular Ganymede and Callisto, terraformed by Planetary Engineers from Luna, and Europa, which is to be terraformed.

The Jovian system is like another planetary system within the Solar System. Despite the backwardness of their equipment, the Ganymedeans make a good attempt to rescue the "Thunderbolt" when that ship makes braking ellipses into the Jovian atmosphere. See recent posts. They compute what the "Thunderbolt"'s fourth free orbit should be but unfortunately the after section, almost cut away by the crew trying to lighten the ship, is torn away by the atmosphere on this descent so that the resulting orbit is completely different.

We saw the Ganymedeans living under a dictatorship fifty years previously but our only glimpse of them during the rescue of the "Thunderbolt" is the accented speech of their radio operator. There must be a lot of background information that never made it into the texts.