Two things
First, i think my textures for the Tempest Missile are messed up. screen is posted.
Second, playing "Into the Lions Den" The Sathanas are shown as flying prisms instead of Sathanases. I think this has been brought up before, but clarification would be nice. Don't have a screenshot of this, but i'm sure people will know what i'm talking about.
Not sure about the Tempest, but the prism thing is not an issue.
Since you never actually fly close to them, and probably won't be able to without missing your window, V used the 'prism' to represent the Saths. It gives you the proper SJ image in your target ID window, and that's all that really matters. There are actually 3 models of the Sath, IIRC. One, you've already seen, one is the regulary Sath, and the last one is the one used in 'Monster in the Mist', I think.
Post your graphics settings, machine specs including graphics cards, and wait for someone else to halp you with the Tempest issue. Though if you had to ask me, I'd advise you to ensure your drivers are up to date. I think there are some issues with Radeon cards with the present MediaVPs.