Three things.
- Hunter Viper Turret
3rd paragraph: ...where the loss of a few artefacts would be preferable... Artefacts can be spelled this way but, from what the internet tells me, most people use 'artifacts'. Here's a little piece about the two http://www.worldwidewords.org/qa/qa-art1.htm
- Wraith Autopsy
2nd paragraph, last sentence. ...unobtrusive; quite why subdermal armour is not present in other aliens we cannot say. This too may be technically correct but to me it sounds better if you drop the 'quite'.
- Directional Thruster Array
2nd paragraph, middle. the part where it says the directional thrusters take the place of the wings, stabilizers and elevators/rudders is stated twice, in very slightly different forms, right next to each other.
Looking at this now, I may be nitpicking.