Pariah Planet by Murray Leinster

From the viewpoint of Darians, the decision of Calhoun's guilt and the decision to execute him were reasonable enough. Maril protested fiercely, and her testimony agreed with Calhoun's in every respect, but from a blueskin viewpoint their own statements were damning.

Calhoun had taken four young astrogators to space. They were the only semi-skilled space-pilots Dara had. There were no fully qualified men. Calhoun had asked for them, and taken them out to emptiness, and there he had instructed them in modern guidance-methods for ships of space. So far there was no disagreement. He'd proposed to make them more competent pilots; more capable of driving a ship to Orede, for example, to raid the enormous cattle-herds there. And he'd had them drive the Med Ship to Weald, against which there could be no objection.