From the readme:
From the film Alien (1979)
comes the 'Semiotic Standard for all commercial trans-stellar & heavy element transport craft', a Ron Cobb designed and inspired set of icons for your personal use. I've done my best to recreate Ron Cobb's symbology accurately and faithfully (discounting a couple of additions of my own), and I think any Alien fan will appreciate this package.
/ico/ (38 .ico 256x256 files)
/png/ (38 .png 512x512 files)
Each icon is alpha masked for transparency and should be fully compatible with all versions of windows.