A leader by its meaning is one who goes first and leads by example, so that others are motivated to follow him. This is a basic requirement. To be a leader, a person must have a deep-rooted commitment to the goal that he will strive to achieve it even if nobody follows him! Joshua was such a man.
An artist's conception shows a terraformed Mars in four stages of development. Terraforming (literally, Earth-shaping) of a planet, moon, or other body is the hypothetical process of deliberately modifying its atmosphere, temperature, surface topography or ecology to be similar to the environment of Earth to make it habitable by Earth-like life.
It is quite typical that terraforming as a notion or concept should arise in these years. Everything must happen in its own time. To speculate on the possibilities of terraforming would have been to early in the 19th century. Then speculations on how to travel to the moon or journeys underneath the ocean were common.