Help me please to understand the marked part:
Kennedy, all right JFK himself. When he was in office, he
stood before the world and promised them a man on the moon within
10 years. Thing is nobody had started working on a space program at
that point. JFK had no data to back up his claims, no inside into the
practicality of space travel.
What does it mean "JFK had no inside into the practicality of space travel"?