Project Hail Mary ending explained: Does Ryland Grace survive and does he return to earth?

(**WARNING: Contains spoilers for Project Hail Mary**)

It’s safe to say you don’t want to be the protagonist in an Andy Weir adaptation. Project Hail Mary continues the writers trend of throwing smart people into an impossible situation and then using science to help them figure out a way to survive. Both the novel and the film versions of Project Hail Mary put their protagonist, Ryland Grace, through the ringer.

The film sees genius school teacher Grace, played brilliantly by Ryan Gosling, getting drawn into an international effort to try and save the sun from a strange life form called Astrophage that’s sapping its energy and threatening all life on earth.

Gosling helps concoct a plan that will see three scientists head to Tau Ceti on a suicide mission to find out why it seems to be the only solar system nearby to our own that isn’t dimming as a result of the Astrophage.

Along the way he meets an alien – and the real star of the film – he names Rocky, who is in Tau Ceti for the same reason. His home planets star is also dying thanks to the Astrophage. Scientific hijinks ensue leading to Grace and Rocky getting launched across the stars on a kaleidoscopic adventure to save their worlds.

But how does it end and what does it all mean? Here’s everything you need to know.

Project Hail Mary ending explained

Around the mid-point of the film, Grace and Rocky realise that the reason Tau Ceti doesn’t appear to be affected by the Astrophage in the same way as their own is because the planet the Astrophage goes to in order to reproduce is also home to microscopic life forms. And those microscopic life forms are then eating the Astrophage, preventing it from reproducing out of control and causing the planets sun to dim.

Grace and Rocky set out to capture some of these microscopic life forms from Tau Ceti in order to use them to eat the Astrophage currently killing the stars in their respective solar systems. And so, they concoct a plan that involves building a huge chain to scoop up samples of the Taumoeba, as Grace calls it, without Grace having to bring the Hail Mary ship too close to the planet.

Of course, the plan goes awry thanks to a leak in the Hail Mary’s fuel tank, which leads to the ship entering an uncontrolled spin and Grace getting knocked unconscious. Rocky, whose own atmosphere is dramatically different from our own, leaves the safety of his bubble to save Grace and their mission.

With a critically injured Rocky now unconscious and potentially dying, Grace sets out to finish their mission by studying the newly acquired samples of Taumoeba. He figures out a way to breed them in a quantity large enough to successfully control the Astrophage population destroying the sun as well as how to make them resistant to the high levels of nitrogen on Venus, where they go to reproduce.

He then uses designs created by Rocky and the same xenonite material that makes up Rocky’s ship, and all of his technology, to create containers to store the precious and dangerous Taumoeba ready for his return home. Thankfully, Rocky awakens having recovered from his injury’s and the two celebrate the success of their mission before preparing to part ways for good in one of the films most emotional scenes.

It is during this return journey, after Grace and Rocky have said their goodbyes, that Grace realises a critical issue. The Taumoeba can easily get out of the xenonite containers Rocky constructed to hold it. And when it escapes it heads straight for its favourite food source: Astrophage.

Astrophage isn’t just dimming the sun. It’s also the fuel source that powers the Hail Mary. As it feeds, the Astrophage creates an enormous amount of energy which it then releases allowing it to propel the ship forward through space. It ‘toots and scoots’ as one character puts it.

Needless to say, the Taumoeba eating all of the fuel on the Hail Mary would be bad news. Luckily, Grace manages to contain the leak quickly on the Hail Mary. However, he realises that Rocky’s ship is made entirely of xenonite, meaning there will be no way for him to prevent the Taumoeba from escaping leaving Rocky stranded and vulnerable to the high levels of radiation.

Grace has enough fuel to return home with the Taumoeba samples or he can send the samples back to earth in the four probes, named for each of the Beatles, and then use his remaining fuel to save Rocky.

Of course, he chooses the latter.

Grace catches up to Rocky just before its too late, reconnecting with his old pal in enough time to save him. The two head off to Eridani, Rocky’s home planet, to save his sun, while the four Beatles make their way back to earth to save our own.

Throughout the film, as Grace pieces back together his memory following the amnesia caused by the coma, one crucial piece of information eludes him. Why he ended up as part of the Hail Mary crew.

The crew of three, one pilot, one engineer and one scientist, were all specially selected and all understood that it was a one way mission. Only, an accident killed both the science officer and his back-up leaving Grace as the only person with enough knowledge to successfully complete the mission. The problem is, he said no. But no wasn’t an option for mission leader Eva Stratt, who drugged him and stowed him aboard the Hail Mary under the premise that he was humanity’s last and only hope.

Only now, as he sacrifices his own return to earth to save Rocky, does he realise she was right.

Meanwhile, Stratt and her team of international scientists collect the four probes sent by Grace and set about using the Taumeoba to save the sun. We see her on route to a remote base where the samples are being held, watching one of Grace’s final logs where he admits she was right about him being the best person for the mission.

Does Ryland Grace survive and does he return to earth?

The film’s epilogue picks up 16 years later and sees Grace living in a huge habitat engineered by Rocky to allow him to survive on Eridani. The habitat creates an artificial climate, controls the temperate of sea water and even causes fog to develop, all allowing Grace to live comfortably on Rocky’s homeworld.

Rocky tells Grace that the Hail Mary is ready for his return to earth. Grace considers it for a moment, before telling Rocky he’ll think about it. Grace then makes the short journey to a makeshift classroom on his beach habitat, where he finds a room full of baby-Rocky’s ready and eager to learn from their strange new teacher.

It’s a full circle moment, we see Grace back in his element as a teacher after going on this incredible journey across the universe. He finds a friend along the way, one he is willing to be brave for. And it is in this friendship at the heart of the film that the solution to saving the world is found.

Though Grace’s return to earth is left ambiguous, the film ends on an optimistic and hopeful note. One that suggests the bond between Grace and Rocky is not the end of the journey but the beginning.

Project Hail Mary is now showing in cinemas.

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