Newman said she also wanted to investigate how people in the future would react to being able to record and playback in memory everything they see, hear and feel via a "cam lens" and neural implants.

"[2] In an interview with Syfy Wire, Newman described the groundwork she had done for the book: "I did a lot of research on Mars itself, on traveling to it, and on geology and the survival challenges posed by living on [the planet]".

On the subject of gov-corps that feature in her Planetfall books, Newman said she envisages a future where huge corporations control governments and monitor their citizens via neural implants.

"[3] Writing at Den of Geek, Megan Crouse called Before Mars "a thrilling science fiction mystery, a societal critique, and a character study".

[4] In a review for Locus, Adrienne Martini wrote that in Before Mars Newman builds on her Planetfall universe with its corporation-controlled governments and their citizen-monitoring via implanted chips.

She remarked that Newman's narrative can be unsettling, leaving the reader "a little removed from the action", which gives the impression that her characters are wrapped in "a thin layer of gauze".

[6] Bourke felt that readers of After Atlas may not experience the full tension of the novel as the timelines of Before Mars and its predecessor coincide and key outcomes have already been revealed.

[7] A reviewer in the Financial Times called Before Mars "a slow-burn psychological thriller" that has a "dark twist" at the end reminiscent of Paula Hawkins' 2015 novel, The Girl on the Train.