The first roadblock facing humans as we seek to expand our presence in the solar system lies in technology. NASA reports that it takes about seven months (measured in Earth days) to travel from our planet’s surface to Mars. Thrillist notes that travel to the Moon only requires a three-day journey, while exploration of Jupiter or Saturn (the next bodies out from Mars) would require a lengthy, six- or seven-year voyage, respectively. On a technical level, our current means of launching satellites and humans at these distant bodies is exactly that, a launch (via NASA). In order to make space travel more feasible for human explorers, we would need to develop a propulsion system that could continually deliver powered flight to a spacecraft, or at least the ability to continually augment flight speed, rather than simply relying on initial launch velocity to carry the craft along to its final destination.
This means a combination of two distinct realities: Humans must develop a brand new means of propulsion that requires far less storage space and mass, a revolutionary idea to be sure; and we must develop the ability to hop between planets and refuel along this lengthy journey. Therefore, technological advancement that would support increased space travel would require both colonization and a capacity for extracting mineral resources from the surfaces of neighboring planets and moons. Continuous habitation in new worlds would be required to support these efforts.
