 Why does the crew later refer to Ha-Adamah as Adam?
But they were disappointed that they found nothing for several hours as they hovered high over the rotation. It was for this reason that Glaser used that model no more, but built others more amenable. On Earth it had read Positive on a number of crack-pots, including Waxey Sax, a jazz tootler who could not even read music. They called it the "You tell me light." And those two ... why, they could well be Earth-people. And one could only wish that all people were like them. There was a man and a woman, and they were clothed either in very bright garments or in no garments at all, but only in a very bright light. "Ha-Adamah," said the man.
 Ha-Adamah is Adam's Hebrew origination.
 He responds to Adam, and they decide it's his true name  Ha-Adamah is Adam's Hebrew origination.  The planet feels so much like the Garden of Eden, that they begin to believe he is Adam  They want to test Adam and see if he accepts it as his name.