The Eridians, if they are in the fanfiction, can be very popular characters. Their advanced technology and their relationship with humans can be explored in many ways. Some fanfictions might even give them more complex personalities and motives compared to what was shown in the original. Additionally, Rocky, if he is included, is a favorite among fans as his unique species and his friendship with Ryland provide a lot of room for creative writing.
The main plot involves a desperate mission to save the Earth. A lone astronaut is sent on a journey filled with challenges and unknowns, having to figure out how to deal with various scientific and interstellar problems along the way.
One interesting concept could be alternate endings. Maybe in the fanfiction, the main character finds a different solution to the problems in the original story. Another concept might be character relationships. Fanfiction could explore deeper friendships or rivalries between the characters that weren't fully developed in the original.
Well, 'hail mary' usually implies something done with little hope but great desperation. So a 'hail mary novel' might be a novel written under tough circumstances, like when the author is facing a tight deadline or has a lot of self - doubt. It could also be a novel that tries to appeal to a very niche or difficult - to - reach audience, sort of like throwing a 'hail mary' in the hope that someone out there will catch it and love the book.
Andy Weir's short stories are often known for their scientific accuracy. His stories usually involve some elements of science, like in his novels. They can be quite thought - provoking, making readers consider different scientific concepts and their implications.