i've seen the info floating around the internet (though i think the source on it is the director's commentary) that the religious medal is a st christopher's medallion (i.e. the patron saint of travellers)
interesting and makes perfect sense! i have heard multiple astronauts have taken st. christopher medals with them before.
i have always thought that an excellent fit for this story could have also been st. jude (thaddeus), a.k.a. the patron saint of desperate or seemingly impossible cases. hail mary situations are basically his thing lol











