Stardate 1800, five years after the first permanent human settlement on Mars. Regular trade routes are established between the inner planets, and the spaceports grow into major cities. Helium-3 mined from the ice giants becomes our most valuable resource, as fusion reactors become the radiant heart of the asteroid-cities far from the warming rays of our sun. Meanwhile, a shadow economy is growing stronger. Space pirates patrol the inky void, employing new versions of classic tactics.

Solar Expansion is a space-themed 18xx game with simple navigation and complex corruption.

Three tiers of operating company (private minors, pirates, and full-cap public) provide creative embezzling opportunities and increase player interactivity. Pirates run protection rackets to benefit themselves (and occasionally the businesses they protect), while the minor companies are pocket-to-pocket cash delivery missiles.

This game borrows the East Asia Expansion engine, removes all the safeties, and takes off like a rocket!

—description from the designer