The will of the Star Spirit and of the Emperor drive the Solar People to expansion. Not at all costs, like some nations, but to the limit they can reasonably sustain with their technology.
In the process, the Morrigna begin to develop the realisation that there may be other sapient, civilised, even spacefaring creatures in the universe. In response to this development, two factions emerge — not in opposition, though, but working together to accomplish the same goal, the Star Spirit's promise, by different means.
On the one hand, the ranks of philosopher-priests develop what might be called a "xenophilic" ethos, establishing houses of learning across the Solar Empire to study the stars and the biology of alien life, speculative linguistics to aid future communication, and any other field that bears some tangential connection to spreading the Good News of the Stars to the stars. Their first order of business, as ordered by the Solar Emperor itself, is to prepare the Great Work, a concentration of the most crucial parts of the Solar Orthodoxy as it has developed over the centuries into a single archive designed to be translated for propagation among every people the Solar People might encounter.
On the other hand, the ranks of crusader-monks, long since reformed into the Empire's internal defensive force, see the opportunity for new crusades to begin and form a new commitment to militarism, with the goal of gaining the loyalty of fiercer, less-diplomatic peoples through shows of force, yet hoping to minimise the needless loss of life. New martial schools crop up across the Solar Empire to train volunteers to become the Solar People's future conquistadors, while at the same time the highest levels of the monastic hierarchy begin their own project ordered by the Solar Emperor, an intense new training system and bible of military strategy focusing primarily on the unfamiliar grounds of space-based combat. Now that the Solar People live under more than one sun, they seek to keep at the forefront of military readiness in these changing times.
The Stars are Strength! The Stars are Unity!