Out “in the black” where the suns rays are much dimmer, future explorers will have to come up with innovative ways to travel to and from the gas giants, dwarf planets and the various moons that dance around their parent worlds.
Since mining hydrogen directly from gas giants is suicidal due to their deep gravity wells and very fierce winds (with the only exception being Uranus), colonists beyond Jupiter may look towards nitrogen to solve their space transport needs.
(Space Travel) Massachusetts Institute of Technology researchers say their new rocket — called the Mini-Helicon Plasma Thruster — is much smaller than other rockets of its kind and could consume just one-tenth the fuel used by conventional systems. […]
The scientists said the Mini-Helicon is the first rocket to run on nitrogen, the most abundant gas in Earth’s atmosphere. Batishchev noted, however, it could be years before the technology can be used commercially.
While this technology will have some value on our home world, these nitrogen powered rockets may prove invaluable to worlds like Titan, Triton and Pluto who seem to be blessed with an abundance of nitrogen, respectively.
If future settlers could find ways to harvest this element from these worlds, then humanity may discover a means to travel not only throughout the outer planets, but perhaps beyond the Kuiper belt as well.