Are there any authentic Jewish sources that claim that the Tower of Babel was a spaceship? I remember as a child being told by somebody that Rav Eibishitz had written something to this effect.
See here for a full explanation of Rav Yonasan Eibeshitz's idea of the generation attempting to build a tower so high it would reach beyond the gravitational pull of the Earth. Then, they planned to have a boat-like vessel atop the tower to be carried up from the Earth's winds to the moon, where they would no longer need to fear torrential rain. (Rav
I've heard people reference Sanhedrin 106b when mentioning it, although there doesn't seem to be any link between the two.
א"ר ארבע מאה בעיי' בעו דואג ואחיתופל במגדל הפורח באויר
Rav said, 'Doeg and Achitophel asked four hundred questions about a tower that floats in the air'
Rashi gives a number of explanations, among them:
במגדל הפורח באויר - לעשות כישוף להעמיד מגדל באויר
About a tower that floats in the air - to perform kishuf to make a tower float in the air.
I suspect that this was the source of the idea.
Since rocket ships are a modern invention, the concept of "building up to heaven" or "being able to go to heaven" is a spiritual or theoretical idea. It is like "aron haporeich ba-avir" (a flying box) in the talmud. As a result, the meforshim do not deal with this on the level of a rocket ship.
a tower whose top shall reach unto heaven
is an expression of rebellion against Hashem, not a physical statement.
Rav Hirsch points out in Noach 11:4 that it means for the glorification of the leader and it is something that will be recognized by everyone and forever. It will be a process that will involve the entire society for generations. This is like the pyramids of Egypt (or the ziggurats of Bavel or the cathedrals of Europe).
The full quote is too long to put here so I have just summarized it.