Peake spoke about the physical toll being in space has on the body as well as adjusting to certain unorthodox routines, such as drinking recycled urine.
The event had to be broadcast live around the entire building after tickets sold out within just 23 minutes.
He spoke of his six-month Principia mission, detailing his nerves while waiting with his fellow crew members for 45 minutes on top of a massive amount of rocket fuel waiting for blast off in Kazakhstan.
And he revealed how they calmed down by listening to Queen, Coldplay and U2 - before the traditional finale of Europe’s Final Countdown.
He said people always ask him about the toilet facilities, adding that 85% of the astronauts’ urine is recycled.
He said: “Yesterday’s pee is this morning’s coffee basically, but actually it tastes absolutely fine. The drinking water on the space station tastes great but it does go through a fairly rapid recycling process.”
He also told of becoming the first UK astronaut to go on a spacewalk, saying one of the most memorable moments of his life was leaving the airlock and “dangling down over this black abyss”.
Mr Peake also detailed the toll being in space takes on the human body, revealing it ages the cardiovascular system 20 years as well as causing a decrease in bone density, accelerating skin ageing, worsening eyesight and weakening muscles.
Within a month of his return to Earth on 18 June he said his body had returned to normal, except the bone density which could take up to a year.
He said this and the “amazing” condition of the astronauts on board the space station who had been there for nine months when he arrived gives him hope that humans will be able to explore Mars.
He said: “It showed me that we can deal with long duration space flight and that as humans we can adapt well to space and that we are not going to have any problem adapting to longer missions like Mars.”
The science centre event was aimed at inspiring people, particularly children, to develop their interest in science.
Mr Peake took questions from young people in the audience - telling one youngster that if his cable snapped during a space walk he would have floated for months before “burning up” on coming back into orbit.
Fan Jessica Deane, eight, presented him with a Principia cake, saying he “inspired her in science and in school”.
She and her family travelled from Manchester specially for the talk and Mr Peake gave her and her brother Alex, five, Principa tags which had been aboard the space station with him.