It is not heresy to speculate, but merely ignorance. We know that aeonic propulsion was gifted to us by divine fiat. And, later, in the time of Saint Ongisron, the lower methods of k-resonance became accepted. Of course, the Unchinta conceived of star travel, and built their own primitive space vessels. But the facts bear out that, whatever their desires, the methods of star travel were simply not available to them.