How did the men in Interstellar go to space for the first time?

In the movie Interstellar, the hero was tricked into space by the professor for the first time. The actor is a former NASA astronaut. Professor A's plan is to build a space station to save everyone on the earth after getting the gravity algorithm and black hole data. Plan B is to abandon everyone on the earth and immigrate to other planets with fertilized eggs. The professor tricked the man into carrying out plan A, but it was actually plan B.