“Project Hail Mary” was written in the late 2010s and early 2020s and was first published on May 4, 2021.

Since you asked “when was project hail mary written,” the key date most readers and forums point to is its publication in 2021 rather than the private drafting period, which Andy Weir has only discussed in general terms in interviews. So, in practical terms, if you’re answering a quiz, doing SEO, or joining a forum discussion, the accepted answer is: it was written and released as a novel in 2021, with official publication on May 4, 2021.

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