Project Hail Mary: Why Rocky And Grace Can't Be In The Same Space

Amazon Studios

One of my favorite things about "Project Hail Mary" is the way author Andy Weir balances impossible situations with clever solutions. He did something similar with "The Martian," where human perseverance and ingenuity are on display from start to finish. "Project Hail Mary" takes that same innovative curiosity and cranks it up a notch with the synergistic addition of a race of too-clever-by-half aliens working alongside humanity to stop an apocalypse. Just like "The Martian," there are plenty of challenges along the way, but the human scientist Ryland Grace (Ryan Gosling) and the Eridian engineer Rocky (James Ortiz) always manage to find a way — including the initial challenge of how to operate in close proximity to one another.

The initial environmental issue hampering their collaboration? The air they breathe. Grace breathes the Earth air, and his body needs oxygen to survive. Not so for Rocky. The alien's atmosphere is mostly comprised of ammonia, making it toxic for Grace to be in the same space as him.

Even worse? Rocky's planet, Erid, is big. That means the gravity is high, and so is the heat. In the book, Weir clarifies that Rocky's ammonia atmosphere is around 29 atmospheric pressure (atm) and just over double the gravitational pull of Earth. Oh, and did I mention that it's hot, too?

Amazon Studios

The first time Ryland Grace approaches Rocky's mid-tunnel wall, along with a strong ammonia smell, he's aware of intense heat radiating from the other side of the partition. He later finds out that this is because Rocky's home planet is around 210°C. (For those of you counting at home, that's over 400°F.) This leads to some comical moments in the book, like parts of a tape measure melting when Grace sends it over to Rocky. At one point later in the story, things get more serious when Grace is hit by a blast of Eridian atmosphere. Here's how author Andy Weir (who is a fan of the Ryan Gosling-led movie) describes the encounter, via Grace's narration:

Twenty-nine atmospheres of pressure at 210 degrees Celsius (over 400 degrees Fahrenheit!). That must be what a grenade feels like.

Fortunately, for the most part, Rocky's exceptional Eridian engineering and access to the marvelous building material called xenonite manage Grace's environmental discomfort, sealing him into a comfortably heated oxygen atmosphere for the bulk of the story. Rocky is also able to build his own ammonia-filled spaces, in the form of his little ball, which he uses to roll around Grace's ship. Later, he builds an entire tunnel network that keeps them close but separated as they work together to save their home worlds.

"Project Hail Mary" already looks like a rare non-franchise blockbuster. It's playing in theaters now.