Keep in mind, for those who care about such things for publishing purposes, that Campbell renewed his copyright on the piece in 1965 (R370757). If he hadn't, Street and Smith published Astounding, so they'd have the next crack at suing you for making another movie adaptation...
That was driving me crazy. I knew I looked it up years ago (I love the story for a variety of reasons; some might notice a notable resemblance to a certain alien hero at DC, what with the strength, shapeshifting, telepathy, magnetic-based flight, and harness), but I was having trouble tracking it down.
Regardless, it's a terrific story with a lot of interesting ideas and, if you come in from a certain frame of mind, the suspense holds up pretty well even when we all pretty much know how it's going to end, at this point.