See The Happy Ending In A Different Daylight

Well all the scripts that Deckard and Rachael drove out into the desert. No mention of Mars.

I believe the script of Hampton Fancher wrote that Rachel took her own life by jumping off Deckard's apartment building. Then a devistated Deckard walked into the desert, planning to end his life too. While he's lying in the sand he saw a turtle on its back fighting for his life. After some time the turtle managed to make a flip-over. The animal crawls away and Rick decides to walk back to the city.