Project Hail Mary: Key Differences Between the Book and Film

Adapting Andy Weir's Project Hail Mary for the screen posed distinct challenges. Phil Lord and Chris Miller returned to directing after 12 years, while Drew Goddard adapted Weir's novel for a second time after The Martian. Ryan Gosling's Ryland Grace is alone for most of the film, and when he does get company it comes in the form of Rocky, a character realized through CGI and puppetry.

The film preserves the central relationship and key themes, but it makes several notable cuts and changes. The movie omits the book's explanation that Grace carries a "coma-resistant" gene, a major reason he is chosen for the mission in the novel. A Russian engineer named Dimitri Komorov, who helps Grace on Earth and contributes to the spin drive in the book, is absent; his role is replaced by other scientists.

A climatologist subplot involving François Leclerc—who helps devise temporary measures such as detonating warheads under Arctic ice to buy time—is also removed. Some plot moments are reworked.

hail mary, andy weir, phil lord, chris miller, drew goddard, ryan gosling, ryland grace, rocky, coma-resistant gene, dimitri komorov