Kinds Of Future Histories

In Poul Anderson's The Fleet Of Stars, two young "Martians," a Terran and a Lunarian, go into the desert without entering a travel plan. Regular Anderson readers remember young human and Ythrian Avalonians taking risks in his Technic History but these are two different kinds of future histories.

Ythrians are aliens; Ythri and jointly colonized Avalon are extrasolar planets reached by hyperdrive whereas Mars is nearby and Lunarians are human beings adapted to live and breed in low gravity. First, Anderson worked well with sf cliches like aliens and FTL (faster than light interstellar travel). Then he questioned such premises in less implausible later works featuring not alien intelligences with FTL but artificial intelligence and STL.

Now, we appreciate both kinds of histories while suspecting that the second kind is more likely.