I am writing a comic, which upon first glance is a survival story about what a forgotten astronaut does to stay alive upon an inhospitable planet. Its first book spans from cycle 0 to cycle 614 with each being 14.8 hours long. The second book will pick up from there.
Having a well-defined start and end is really helpful. But how may I prevent the middle or whatever events I add from feeling like a laundry list of events?
Please explain why, if your story tells of how an astronaut survives on an alien planet, that narration should feel like a to-do list? There will be intense emotions (shock at discovering what happened, fear of death, hope shattered, despair, hope regained), there will be dramatic turns of events (solutions he attempts will almost seem to work only to fail at the last moment), there will be interesting and exotic environments (spaceship, alien planet, future technology). Why should any of this feel mundane and commonplace?
Your story could become boring if you plan to structure your narration like a full recording of everything that happens. Your question seems to indicate that you may plan to dedicate one section of your comic to each 14.8 hour cycle and have the same fixed number of pages for each of these "days". That may indeed turn your story into a long and potentially boring list of things your astronaut does, because not every hour of every day might be equally interesting.
Usually the story structure follows the demands of the story, not the other way around. Most narrations skip much of what happens and only tell the interesting parts. The common everyday parts like sleeping are usually left for the audience to supplement in their minds, and uneventful passages are usually briefly summarized ("Three weeks later..."). On the other hand, what may be mundane to the person doing it may be interesting to the readers. For example, how bushmen sleep (with their upper bodies propped up on their arms so insects don't crawl in their ears) or using a toilet in zero gravity might be banal to the person doing it but worth showing to your readers.
The everyday life of an astronaut surviving on an alien planet is potentionally interesting enough in and of itself not to become boring even if you recount it in its minutiae.
Maybe you should read some tales of survival to understand how these kinds of stories work. I recommend The Martian by Andy Weir, of course, but also Pincher Martin by William Golding.
Characters grow over the course of the work; that's what gives the work meaning. Each scene should play into that expected trajectory.
Example: In Macbeth, Lady Macbeth goes:
Normal Life > Temptation > Fall > Guilt > Madness > Death
In every scene, Lady Macbeth's decisions propel her down this path. You should plan out a trajectory for your astronaut, and link each scene to that character arc. Because the scenes have meaningful growth, they will feel necessary and interesting.
As @codeMonkey described, in part, when your character's decisions move the story forward your story feels less like a series of 'and then x happened,' and more like the consequences of the character exercising their agency.
I found it a challenging idea to apply until I heard Trey Stone and Matt Parker (The South Park Guys) describe their storyboarding process. They connect the moments of their story by 'therefore' or 'but.' This results in the stories they come up with as a series of events caused by either the consequences of the character's actions/desires or reactions to those same desires/actions. The reactions can be from other characters or just bad luck. The important part is the characters get frustrated when they go after what they are wanting.
Another way to imagine it is to frame your story in terms of your character motivations and goals and the obstacles in their way. In each scene the character wants or needs something and devises a plan to satisfy that need but there is something in their way --- it could be the environment, themselves (what they want is self-defeating), or another character's intentions.
When the events of a story are presented in this fashion, they feel like our own struggles and they feel less like a series of unfortunate events, and that makes them more engaging.
