The Grandeur of Auriga uses hypersail tech and has refined it to its peak. In hypertravel the sails help catch tachyonic currents (or whatever) to augment the ship's own hyperdrive-propelled movements. More advanced sails can actively use field-manipulation to add a boost, like supplementary reactionless drives (there are probably instances where Aurigan warships' damage hyperdrives died mid-jump and the sails did the rest of the work). Out of FTL, lower-end sails just fold up and the masts act like nacelles. Higher end sails have secondary realspace field-manipulation capabilities, augmenting shields (or being the shield generators themselves), deflecting incoming rounds or even using hyperfields and grav-waves to slice smaller enemy vessels. Most lower-end hypersails are composed of physical meta-materials, whereas the most advanced Aurigan sails are made out of energies projected by masts that channel orgonic energies.
In short, it's a more complicated parallel-version of the Solarians' more advanced hyperfield tech, though the USSF's vessels requires no masts, using fields can be projected by smooth-hulled blade-like Strikestars. The Apexai warsaucers of old probably used hyperfields to go Doctor Manhattan disassembly on Braglan warfleets.
NEUROM vessels, particularly those of the Sternheim, are of similar caliber to their Aurigan counterparts. But due to their old Warmoon-derived tech and their psyches, their sails are sterner (lol duh), more rigid but more durable in form but less versatile than the Aurigans.' So their sails aren't sails, but solid wings. Their capships probably resemble Victory-class ISDs or enlarged X-Wings and Lambda shuttles, with wings that expand in hyperspace and fold or collapse into stubby parts that have supplemental shielding purposes while weapons and sensors pop out of the wingtips.
And their brand of humanism makes some vessels, the significant ones, oddly humanoid-shaped. The old Sternheim warmoon could've had the silhouette of a man on a throne.
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