STL and Social Change

In Poul Anderson's Orbit Unlimited, Tau Zero, Harvest Of Stars, Starfarers and The Boat Of A Million Years, human beings cross interstellar distances at slower than light (STL) speeds and colonize other planets. In Starfarers, Boat and "The Queen Of Air And Darkness," which is set in the same future history as Orbit Unlimited although in a different planetary system, they also contact extrasolar intelligences.

The idea of STL interstellar travel raises several questions.

(i) How do crew members remain sane and interact with each other during long voyages?
(ii) What do they find in extrasolar systems: life; intelligence; habitable planets?
(iii) If they return home, how much will their home have changed in their absence? (Will they meet or be "aliens" on their return?)

Potentially, a long novel or an entire series could follow the career of a ramjet captain as he completes say two complete circuits between Earth and several extrasolar colonies: beginning and ending on Earth and also visiting Earth at the midpoint? Each return to a particular planet would be an arrival in a later historical period or even in a new civilization. Larry Niven's Leshy Circuit series was a first step in this direction.

The hero of Joe Haldeman's The Forever War returns from interstellar war to a changed Earth, then re-enlists in the war because he cannot adjust to life on the changed Earth.

Anderson shows us how male and female crew members interact with each other although they can also resort to interactive virtual reality or even, in some futures, to interactions inside conscious computer systems. In Starfarers, alternating chapters show us:

life inside a spaceship on a ten thousand year round trip;
life meanwhile in the Solar System and on some extrasolar planets;
thus, a single volume future history in which:

the starfarers of the title evolve into the "Kith" interstellar traders of earlier short stories;
armed nation states persist and expand into space so that there are wars, e.g., for possession of valuable asteroids;
there is also a succession of undemocratic regimes and new religions.

I remember that the spaceship encountered non-humanoid aliens and returned to a radically changed Earth. However, my time with Anderson is now divided between rereading and blogging. Since, currently, I have reread only to page 90 of 495 in Starfarers, there will now be an intermission...