Turns out there are two websites and the keys to cracking them were in their names. They are:
For the first, the clue was "eridu". Eridu is the name of an ancient city in Sumeria. If you go to its wikipedia page, the password is staring you right in the face in bold letters. Did you catch it? I'll give you the answers below after you've had a chance to guess.
The second one took longer to crack, but the clue was "245409". HD 245409 is a designation for the constellation Orion. If you google around enough, you'll end up on the wikipedia page for Cosmic Call, which was a radio signal sent out into space from 1999 to 2003. Once again the answer is staring right at you in bold letters.
If you haven't guessed either of them, don't worry. In my attempts, I looked at both of these wikipedia pages and didn't see the answers. Ready to know what they are? Ok...
#1: http://www.projectprometheus.com/eridu/ Password: tell abu shahrain#2: http://www.projectprometheus.com/245409/ Password: ddm2ddm2ddm2amamambigbigbigbmesmpp,
Tell Abu Shahrain is the name for the modern city that lies on the same ground where Eridu once stood.
So obvious now, so hard to find then.