'Ad Astra' Ending Explained: Roy McBride's Voyage in Search of Alien Life

Director James Gray’s heady space epic, Ad Astra opens Friday, and if you walked out of the theater feeling like someone threw a handful of sand into your brain, you’re not alone.

Ad Astra had its world premiere at the Venice Film Festival on August 29, and the festival crowds gave the it mostly positive reviews with universal acclaim for Brad Pitt’s leading role as the emotionally disconnected Roy McBride. But Ad Astra also feels like Homer’s Odyssey in space — disorienting, surprising, and confusing.

The entire first half of the film feels like a thrilling piece of realistic science fiction set in the uncomfortably near future. While advanced, most of the technology seems achievable within the next few decades. But will we really be able to travel all the way to Neptune in our lifetimes? Ad Astra wants us to think so. The further Roy travels from Earth, however, the tone becomes more cerebral and the scope, overwhelming.

Let’s take a closer look at the ending to Ad Astra to digest what it all means.

Full spoilers follow for Ad Astra.

What’s Threatening to Destroy the World in Ad Astra?

Early in Ad Astra, Pitt’s Roy McBride is performing maintenance on a massive antennae that reaches into the atmosphere from Earth. Some kind of energy flare of unknown origin causes catastrophic power surges across the planet, killing more than 40,000 people.

We soon learn that decades prior, Roy’s father Clifford McBride — a renowned astronaut and space hero — led something called the Lima Project to the outer limits of the solar system, looking for signs of alien life. He disappeared and was presumed dead years ago. But now, U.S. Space Command thinks Clifford might still be alive, and something he’s doing is triggering these power surges. They task Roy with traveling to the moon, where he’ll hitch a ride to Mars, where he’ll then use a communication laser to message his father.

Roy eventually has to make the full journey out to Neptune (which takes months), where he does find the Lima Project station — and his father. We learn that when the rest of the crew mutinied, the anti-matter battery powering the station was damaged. Clifford had no way to fix it.

But Roy brought a nuclear bomb with him, and he uses it to blow up the entire station, saving humanity in the process. Good for you, Brad.

Does Clifford McBride Discover Alien Life With the Lima Project in Ad Astra?

The whole point of the Lima Project, and a persistent source of anxiety and anticipation throughout the film, involves Clifford’s dogged insistence that alien life exists and that the only way to find it is out in Neptune or beyond. Is he right?

Was it worth it for Clifford to abandon his family and doom his son to the emotional scarring he endures throughout Ad Astra? Years of solitude extract a heavy toll on Clifford, and so does the guilt he carries after killing his entire crew during the aforementioned mutiny.

The greatest source of his misery, however, is in the revelation that even out in orbit around Neptune, there’s zero sign of alien life anywhere. He does capture a large amount of data about potentially inhabitable worlds in other galaxies and star systems, therefore making his research worth a lot to humanity. But he’s sad enough to vault off the space station to careen into the emptiness of space and certain death.

So no, there’s no supernatural twist or alien deus ex machina waiting at the end of Ad Astra. There’s just one man’s desperate search for his father that feels like the Odyssey mixed with Heart of Darkness rather than anything that even remotely resembles Interstellar. That makes Ad Astra that much more realistic — and heartbreaking.

Ad Astra will be released September 20, 2019.