Originally it is certainly not Helvetica, which was only created in 1957. If you look at photos of the old jacket patch logo (the one with the yellow fins on the stylized rocket), the "R" is very different from the one seen on the modern logo, and is 100% not Helvetica. I have no idea what that was, possibly hand-drafted. The current one definitely looks Helvetica-ish, but with only 3 letters to go on it's hard to be sure.