The awesomely retro print is dated Feb. 26, 1965, and it captures the aesthetic of space-based art at the time - it looks as if it could be the cover of a 1960's science fiction novel.
The poster is advertising NASA's traveling space-education program "the Spacemobile." These mobile outreach units would travel to schools and events to tell students and members of the public about space sciences and the work being done by NASA.