Beyond And Within The Frontier

On a finite globe, there is no longer a frontier between known and unknown territory although much remains unknown. Beyond Earth, there will always be a frontier between known and unknown space with much remaining unknown in both.

In Poul Anderson's Technic History, explorers continually extend known space while bypassing many less interesting planetary systems. Therefore:

the trade pioneer crew seeks new sources of profit not beyond the frontier but among the bypassed systems where they are less likely to be disturbed by explorers;

Pharaoh, the clouded planetary base of the Baburites' oxygen-breathing mercenaries, is probably within known space for the same reason.

In Mirkheim, published in 1977, David and Coya Falkayn know that they will not remain on Earth and might not settle on Hermes either. David comments that it is a big universe. Indeed. Nearly everything about Ythrians was published before 1977. Thus, we already know that the Falkayns will settle, with human beings and Ythrians, on a planet that was discovered during the first Grand Survey and therefore is well within known space.