Weekly video updates from yours truly, delivered via email. I'll keep you posted on my progress so that you know that your money is being put to good use. I may even read you some bits from time to time.
All of the above, plus an old-fashioned, hand-written, snail-mailed thank you note. I'll stick in something fun, too. A rough sketch of the ship, some of my old notes, a tiny space collage -- everybody will get something a little different.
All of the above, plus I'll name a minor character, ship, planet or colony after you (my choice). Please note that not everybody in the galaxy is a nice person. I may also need to tweak the spelling a smidge if the only people left to name are aliens.