Famously competitive Lance Armstrong throws in the towel on 'Stars on Mars'

There was a bit of a shocker tonight on Stars on Mars as Lance Armstrong exited the reality competition show. But rather than be eliminated by being determined as “not mission critical,” which is the normal course of the game, Armstrong left of his own accord.

The show features 12 varied personalities living together in an environment meant to simulate life on Mars. Each episode, they are given a challenge that they must tackle in teams, and by the show's end, the person deemed least “mission-critical” is sent home.

After a rough stretch of missions where Armstrong struggled to get along with many of his fellow castmates, the famous cyclist was starting to get the feeling that the end was near.

"I woke up today, and thought, 'I'm going home today,'" Armstrong said to Cat Cora early in Monday's installment.

The episode included a mission to track down and expel an invader in their home on the red planet. Armstrong was paired with Modern Family’s Ariel Winter, with whom he has clashed all season long. They managed to crawl through an air vent together without any major drama, but both ended up in the week's bottom three alongside NBA legend Paul Pierce. And that’s when Armstrong pled his case — to go home, that is.

“Life on Mars is not easy. You can't put 12 different people together in a room and expect them to get along,” said Armstrong to his fellow teammates. “And that's what I'm struggling with. And so I think going forward, that would be a liability, not just for myself but for the team. It’s been a hell of an honor, so I have decided to exit the project."

It was a rather ignominious fate for a man whose entire reputation as a competitive cyclist was built on being a gritty, relentless fighter. But Armstrong was somewhat of an outlier from the start of the season, clashing with some of the players, in particular Winter, with whom he butted heads over his take on trans-athletes.

Based on the reactions of the rest of the cast, they weren’t too bummed to see Armstrong go. But viewers watching and reacting on social media seemed a little more surprised by the move.

Stars on Mars airs Mondays at 8 p.m. on Fox.