Here's an idea.
Get Photoshop.
Select the Clone Stamp tool on the side (if its Photoshop 7 or 8, then click and hold on the Healing Brush and Clone Stamp will appear).
Alt-click on an empty area of the saucer, then left-click on the text. It should copy the colors from one section of the saucer and wipe out the text.
You might also want to try doing the same thing with the healing brush, if the clone stamp doesn't work right.
Then, use the Text tool to write something, then right click on the text and choose warp text, and warp it to look like the text on a starfleet hull.
Save as .bmp.