Wagoner said he was detained within hours of photographing the six-story steel vehicle at the aerospace company's private launch site in Boca Chica, Texas.
"I get arrested, I get taken to jail, and spent the night with seven other guys in a 12-by-16 concrete cell, sleeping on the floor," Wagoner told Business Insider.
On Sunday, Wagoner approached SpaceX's launch site from its east side, and walked up to Starhopper, taking up-close photos of the gutted rocket ship and posting them on Facebook.
Within four hours of uploading images, Wagoner received a surprise call from a sergeant at the Cameron County Sheriff's Department, accusing him of trespassing.
"He says, 'They say that you trespassed, and we have to file criminal trespassing charges against you,'" Wagoner told Business Insider.
Sheriff Omar Lucio, the county's head law-enforcement official, told Business Insider on Wednesday that SpaceX pressed charges and that his department filed them against Wagoner.
"The reason for that is simple," Lucio said. SpaceX has "a lot of equipment and chemicals out there — it's for the safety of the public."
The sergeant who called in Wagoner and questioned him ultimately arrested the SpaceX fan on suspicion of criminal trespassing, a class B misdemeanor in Texas. The offense is punishable by up to six months in jail and a $2,000 fine, according to the Texas penal code.
Wagoner told Business Insider he didn't see any "no trespassing" signs and wasn’t approached by any kind of security guard, saying that "a child could have easily done what I did."
"I didn't think I did anything wrong. I posted the pictures on Facebook. If I thought I did something wrong, I wouldn't have posted them," he added. The original post was taken down by the photographer himself, however, later he posted additional Starhopper pictures which showed no fence or signs.
"I want to try to have a good relationship with SpaceX. I don't want to mess it up," Wagoner said, following the hope that the charges will be dropped, adding that the criminal charge now puts him "kind of in a quandary."
Wagoner on Tuesday asked Musk in a tweet to pardon him for his "photographic exuberance, noting that he has "nothing but admiration and best wishes for Elon Musk and the work that he does with SpaceX to make us a multiplanetary species."