'Project Hail Mary's ending makes one big change from the book. Here's why.

Screenwriter Drew Goddard breaks down Eva Stratt's fate.
 By 
Belen Edwards
 on 
All products featured here are independently selected by our editors and writers. If you buy something through links on our site, Mashable may earn an affiliate commission.
Ryan Gosling in "Project Hail Mary."
Ryan Gosling in "Project Hail Mary." Credit: Jonathan Olley

Like any book-to-film adaptation, Project Hail Mary makes some changes to its source material.

In most cases, Project Hail Mary's changes look like removing elements of Andy Weir's novel in order to streamline the film. For example, in the book, a key part of finding astronauts for the Hail Mary mission is determining whether they have a very rare coma resistance gene, all of which is missing from the movie. Another omission? A plan to power Astrophage production by covering the Sahara Desert in solar panels.

However, Project Hail Mary does make one addition in its final minutes that isn't in the book.


You May Also Like

The film ends very much like Weir's novel, with biologist Ryland Grace (Ryan Gosling) living not on Earth, but on alien Rocky's (voiced by puppeteer James Ortiz) home planet of Erid. He's sent the Hail Mary's beetle probes back to Earth with instructions on how to breed the Astrophage-eating Taumoeba and save the sun. In the book, after Grace has spent years on Erid, we learn that the sun's luminosity has been restored, meaning Grace's research made it to Earth and humanity is saved.

However, we never actually see what that process looks like in Weir's book. In fact, we never return to Earth, as we're in Grace's mind the whole time.

The movie, on the other hand, does bring us back to Earth as the film winds down. It shows us its now-frozen oceans, a result of global cooling due to the sun's dimming. It also shows us what's happened to Stratt in the years since the Hail Mary launched.

Don’t miss out on our latest stories: Add Mashable as a trusted news source in Google.

Stratt's fate remains a mystery in the novel, although she believes that she'll eventually wind up in prison due to the extreme actions she took to get the Hail Mary off the ground. (The Sahara Desert plan, for example, proves an environmentally destructive resource drain, although it gets the job done.) The film takes a more optimistic approach, showing that Stratt is still alive and has received the beetles. Now, she's ready to start work on the next phase of Project Hail Mary.

"Quite honestly, I love writing Stratt," screenwriter Drew Goddard told Mashable while discussing Stratt's ending. "This movie is about three characters, really. It's a triangle between three characters, and we need to give her her moment."

Thus, Stratt's epilogue was born, granting us a hopeful glimpse into humanity's recovery effort.

Goddard continued: "That's what great about movies. You can cut away, whereas the book stayed with Grace. Once I put [the scene] in, no one questioned it. I was really grateful that they let us do it, because I thought it was really important to see her."

Project Hail Mary is now in theaters.

A woman in a white sweater with shoulder-length brown hair.
Belen Edwards
Entertainment Reporter

Belen Edwards is an Entertainment Reporter at Mashable. She covers movies and TV with a focus on fantasy and science fiction, adaptations, animation, and more nerdy goodness. She is a member of the Critics Choice Association and the Television Critics Association, as well as a Tomatometer-approved critic.

Mashable Potato

Recommended For You
Shop the best book deals in Amazon's Spring Sale — save on popular titles like 'Project Hail Mary'
Beach Read, Project Hail Mary, and A Walk in the Park book covers on abstract background

Want to see 'Project Hail Mary' before the public? Your Prime membership unlocks early access.
Ryan Gosling as Ryland Grace in 'Project Hail Mary'



'Project Hail Mary' review: Ryan Gosling delights in a sci-fi buddy comedy
Ryan Gosling plays Ryland Grace in "Project Hail Mary."

More in Entertainment
How to watch 'Wuthering Heights' at home: Margot Robbie and Jacob Elordi's controversial romance now streaming
Margot Robbie and Jacob Elordi embracing in still from "Wuthering Heights"

How to watch New York Islanders vs. Philadelphia Flyers online for free
Matthew Schaefer of the New York Islanders warms up

How to watch Mexico vs. Belgium online for free
Israel Reyes of Mexico reacts

How to watch Brazil vs. Croatia online for free
Vinicius Junior #10 of Brazil leaves

How to watch USA vs. Portugal online for free
Joe Scally #19 of the United States

Trending on Mashable
NYT Connections hints today: Clues, answers for April 3, 2026
Connections game on a smartphone

Wordle today: Answer, hints for April 3, 2026
Wordle game on a smartphone

NYT Connections hints today: Clues, answers for April 2, 2026
Connections game on a smartphone

Wordle today: Answer, hints for April 2, 2026
Wordle game on a smartphone

NYT Strands hints, answers for April 3, 2026
A game being played on a smartphone.
The biggest stories of the day delivered to your inbox.
These newsletters may contain advertising, deals, or affiliate links. By clicking Subscribe, you confirm you are 16+ and agree to our Terms of Use and Privacy Policy.
Thanks for signing up. See you at your inbox!