It’s commonplace to praise actors for holding nothing back. But the genius of Gosling’s personal-best performance as Neil Armstrong, the aeronautical engineer who became the original NASA moonwalker, is his ability to keep his audience enthralled and empathetic by holding just about everything back. Gosling’s Armstrong is a buttoned-down, tightly focused obsessive who relentlessly stifles his emotions while dealing with challenges ranging from the fatal illness of his young daughter (early on, we see him methodically searching for specialists somewhere, anywhere, to treat her brain tumor) to a harrowing emergency during the Gemini 8 mission that almost ends with an irreversible spin into the unforgiving blackness of space. Periodically, we catch fleeting, teasing glimpses of what he hides from the world, and from himself. Much more often, however, Gosling provocatively insinuates that Armstrong isn’t just reluctant but quite possibly incapable of bearing his soul. In what arguably is the most revealing scene in “First Man,” Janet Armstrong (Claire Foy) practically browbeats her husband into warning their sons about the possibility of his not returning from his Apollo 11 adventure. So he sits down with the boys and dutifully answers their questions — with words that sound as vague, scripted and rehearsed as his responses to total strangers at a press conference. It’s as though this astronaut made up his mind long ago: To succeed and survive, feelings are not an option.