British astronaut Tim Peake has revealed how he coped life on board the International Space Station.
He said people always ask him about the toilet facilities, adding that 85% of the astronauts' urine is recycled.
Peake told the event at Glasgow Science Centre for Sundays that "yesterday's pee is this morning's coffee".
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."
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.
He also spoke of his six-month Principia mission, describing what it felt like to become 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".
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.