95% carbon dioxide. The air is unbreathable, and the atmospheric pressure is less than 1% of Earth's, requiring pressurized suits at all times outdoors.

Each book adopts a first-person, "autobiographical" narrative style, giving a distinct voice and personality to its subject. This approach is a hit with both kids and adults, as one Goodreads reviewer noted that the books are "plenty punny for the adults while also being educational for every age". The parent blog "Momma Braga" gave it a glowing review, stating, "We love the interesting facts within the book and it is done in a fun way to really get children engaged in the learning".

Bodily fluids shift toward the head, causing nasal congestion, facial puffiness, and increased intracranial pressure that can alter vision.

Mars is inherently hostile to terrestrial life. The PDF outlines the immediate environmental hurdles and the technology required to mitigate them: