I tried to do my duty, Cooper. But I knew, the day that I arrived here, this place had nothing... and I resisted the temptation for years. But I knew that, if I just pressed that button, then somebody would come and save me.
~ Mann revealing his true intentions.
When I left Earth, I thought I was prepared to die. The truth is, I never really considered the possibility that my planet wasn't the one.
~ Mann to Cooper
There is a moment…
~ Mann's last words
Dr. Hugh Mann, or better known as Dr. Mann, is the main antagonist of the 2014 science fiction film Interstellar.
Dr. Mann was the Project Lazarus leader who convinced eleven other scientists to participate in the cataloging of a dozen habitable worlds on the other side of the wormhole. Mann, however, was stranded upon an icy planet that was uninhabitable and could not substitute Earth as the new home planet for life (in Interstellar, the Earth is dying and failing to nurture life, forcing NASA to send astronauts and engineers to search for a new home). During his time on the icy planet, Dr. Mann realized that he had been sent there for nothing, stating he knew the moment he landed that his planet wouldn't be the new home for humanity. Feeling hopeless knowing he would die for nothing, the cowardly, or "survival" side of him began to convince him to stay alive, and after years of resistance, Dr. Mann finally went through with his survival intentions: to fake his planet's data and put it in a more optimal perspective, and to be a leader on humanity's new planet. So he fakes the data and goes in a deep cryogenic sleep while he waits for someone to retrieve him.
Mann is reawakened by the crew of the Endurance approximately 30 years later due to the time dilation of the Endurance on Miller's planet. Mann was critically low on power at this point and Joseph Cooper had to manually break open his sleep-bag to wake him. Once Dr. Mann awakens, he cries, and Cooper holds him and comforts him as Dr. Mann releases his pent-up emotions. Dr. Mann is shaken by the appearance of people coming to his rescue, stating he had not set a wake date to his sleep. He and the crew discuss about the planet's environment and any further planning that would be implemented, when a video message is received, where the somber revelation of Professor Brand's death is told by Cooper's daughter. The crew is shocked to hear from her that Professor Brand had never actually believed in Plan A, but had to make the crew and everyone else believe it. Brand states she has no idea what Cooper's daughter was talking about, when Dr. Mann chimes in, saying he does know. Dr. Mann reveals that Professor Brand had solved his equation that would be able to bring humanity to another planet before he had even left for space, and the reason why Professor Mann couldn't use it was that the equation couldn't reconcile relativity with quantum mechanics. He continues by saying since Plan A was impossible, they had to go ahead with Plan B, and the reason why Professor Brand didn't tell people was because people would be naturally selfish and attempt to save themselves and their children instead of thinking about the human species. Dr. Mann even goes to commend Professor Brand because this was an incredible sacrifice, telling this monstrous lie and abandoning his humanity to save humanity, which in a way is a rather noble sacrifice, but Cooper angrily retorts by saying the great sacrifice was being made by the people on Earth who were going to die, as Cooper interprets this "sacrifice" as merely arrogance in the belief that Earth's case was hopeless. Dr. Mann somberly states that it is in fact hopeless, and that they are the future of humanity.
Once the truth about Brand's Plan A being impossible was revealed, it was decided that Cooper would return home while Mann, Romilly and Brand would proceed to carry out Plan B on Mann. Mann, knowing his planet could never support human life, in secret, attempts to murder Cooper, seeing his death as necessary to the completion of the mission, as Mann did not want to let Cooper leave for Earth with the Endurance, since he now needed it to get to Edmund's planet. Dr. Mann and Cooper have a long dialogue, where Cooper berates Mann as a coward. Dr. Mann shockingly agrees with him, but retorts at the same time by saying nobody had been put through the emotional and psychological trauma he went through when he stayed in solitude for all those years on the icy planet. The two men continue to fight, and Dr. Mann head-butts Cooper's faceplate, causing it to crack. Dr. Mann prepares to leave, stating to Cooper that he is making a noble sacrifice for humanity. After witnessing the explosion of his capsule with Romilly inside, Mann changes his plan to lie about Cooper's death being an accident and instead attempts to maroon the Endurance crew on Mann's planet in order to live and to finish Brand's Plan B mission on his own, since the crew would figure out Dr. Mann had lied and presumably imprison him. However, Dr. Mann only succeeds in stealing Ranger 1 and docking it imperfectly on the Endurance, since he is unfamiliar with the proper docking procedure.
While dismissing Brand's pleas to not do this without the rest of the crew's authority or action, arguing that the plan is to save all mankind, he announces "There is a moment" before the airlock depressurizes, killing him and critically damaging the Endurance. TARS and Cooper rush to undo Mann's damage, which they succeed in.
Mann was a scientist who at first had a very strong belief for finding another habitable planet and left with the hope his planet would be the one to sustain human life. However, as time passed, he began to lose hope due to the fact that the planet he was on had absolutely no chance to sustain life. So with this feeling of hopelessness taking him over, he eventually chose his own life over the mission after years of resisting this temptation, so he faked the data for his planet and put himself in a cryogenic stasis in the hopes that someone would rescue him.
His cowardice, or as he says his "survival instinct", controls him to the point that he committed murder because they need the Endurance to go to Edmund's planet and initiate Plan B, as Mann's Planet could not physically sustain human life. Despite his cowardly actions, he was still a good man at one point, with Brand pointing out he was the bravest man she ever knew. When Mann cracked Cooper's faceplate, he told Cooper he was doing this for humanity, and that Cooper was dying for a righteous cause. And in the grand scheme of things, had Cooper not been able to transmit the data necessary for Plan A, the humans on Earth would eventually die, and taking the Endurance back to Earth would have been for nothing since they all would have died anyway, so in a way, Mann's actions could be considered for humanity. He was also remorseful, saying that he couldn't bear to watch as Cooper suffocated. He even insisted to Cooper that had anyone else gone through what he did, they would have become exactly like him and done exactly what he did, saying few men had ever been tested like he had been tested.
Mann being awakened from his deep sleep by Joseph "Coop" Cooper
Mann informing Cooper and his crew that the people of Earth are beyond saving
Mann giving Cooper a tour of his planet before attempting to kill him
Mann leaves Cooper behind and prepares to steal Ranger 1
Mann attempting to manually dock his spacecraft on the Endurance despite Cooper's protests
Mann is killed when he fails to dock properly and his spacecraft depressurizes
Dr. Mann turns out to be the only Christopher Nolan villain yet who is not part of the film's central conflict, because Interstellar is the only film of the director which uses different type of the main conflict rather than confrontation.
This Is not the only role that Matt Damon played an astronaut; he portrayed Mark Watney In The Martian, which was released a year later after Interstellar. The difference is that while Watney is the main protagonist of The Martian, Dr. Mann is the main antagonist in Interstellar.