I'm interested if we can use the story as a glimpse into the scientific culture of the 1860s and how the community at the time viewed the possibility of space travel.
Was Verne trying to base his novel in accurate physics/chemistry/astronomy of the time, or did he intentionally diverge from what was already known for the sake of the plot? In what ways was he, and the science he used as a foundation, later found to be accurate? Was the book popularly received as pure fantasy, or was there a hint of "someday this will be a reality"?
Thanks in advance.
Lets first take a look at what happens in the book, a group of three people are shot in a ballistic capsule from a very large gun/cannon. The projectile is fired in a course that would be essentially be a free return trajectory. In the sequel "Around the Moon", it is later mentioned they attempt to fire rockets at what they call the 'dead point' where the gravity between the two bodies (Earth and Moon are equal), basically describing a Lagrange point.
So, bit by bit:
Ballistic launch and travel - Obviously Newton published Pincipia in 1687 which described basic laws of motion. Most importantly for us here, is the 'object in motion, stays in motion.'
We also have more detailed look at what is required to move bodies already in motion with the beginings of the rocket equation which has been derived by William Moore in 1813 (A Treatise of the Motion of Rockets). So either Verne knew, or correctly guessed, that his ship had to be launched in a perfect trajectory since he didn't describe any maneuvering thrusters.
So, while Verne never attempted to the math to see if this was possible (to my knowledge), It certainly stands to reason that he knew the craft couldn't alter it's course without proper thrust since this had been established in many scientific circles. Tsiolkovsky (of which the rocket equation is named after) eventually did the calculations and figured out the launch itself would be impossible, but this wasn't until the early 1900s. He calculated the gun would have to be impossibly large. I forgot the work he did this in, but I shall try to find it.
The Dead Point - Again, Verne hesitates to go into the math and never mentions it by name, but we certainly knew these points existed. Lagrange had published Essay on the three-body problem in 1772. The crew of the moon ship also is on their voyage home and wait until the Lagrange point to fire their landing rockets in an attempt to enter the Moon's orbit. In the end, they don't fire the rockets in time and just fall back to earth. Verne is correctly describing the points where one could enter the moon's orbit and what would happen if they didn't fire their rockets in time.
Life support - Here is perhaps where Verne takes the wildest leap. He adequately describes the rough time it takes for such a journey, however, he never mentions how air is recycled. We already knew that fresh air was a key to survival at this point by looking at the history of diving bells. If we look at the published history of them in an article entitled "A Brief history of diving and decompression illness" by Acott, it appears that designs for using pumps/bellows to force oxygen down to a bell existed as early as 1689 and used in 1789. To further note, it was certainly widely held knowledge that space was a vacuum at this point. Pascal (among many scientists before him) simply extrapolated from the fact that air pressure gets lower as you increase in altitude.
One thing that I cannot find is when studies on the amount of g-forces a human body began, but I know in the book they attempt to address it with a solution that is never described in detail.
Also, I do apologize if this doesn't answer your question. I've merely attempted to describe various events in the book and compared it to scientific knowledge of the time. Sadly, I would be the wrong person to ask about Verne's motivations and writing styles. I would like to imagine he took creative liberties only when he had to and tried to use as much of his scientific knowledge as he had.