were crewed by Trolls. They were expendable.
In fact, they were more expendable than her own MDMs. Above the beta band, nothing else could get through the interface of a translation field and an n-drive's field. The translation field exerted a "dimensional shear" effect on anything that tried to cross it, while the n-drive distorted the space about a vessel and distributed all the tremendous mass it built up at relativistic velocities across the surface of its field. Either alone could be handled; hitting their combined strength with anything less than an MDM was like trying to split a planet with a claw hammer.
Once a ship dropped into the lower bands or sublight, it was another matter. But the Kangas and their Trolls wouldn't do that until they arrived at Sol, and they could not be permitted to arrive.
Yet the threat to humanity rode in the Ogre, which was precisely why the light cruisers had dropped back between it and Defender. Their translation fields were the only ones the seekers in Defender's MDMs could now "see," and each would cost her two or three—possibly even four—MDMs