Ms Lieu is one of five Britons to be shortlisted for Mars One, having previously been named on a longlist of 600. The other Britons are Hannah Earnshaw, a 23-year-old PhD student at Durham University; Ryan MacDonald, 21, an Oxford University student; Alison Rigby, 35, a science laboratory technician and Clare Weedon, 27, a systems integration manager.
With nothing to build on but dusty rock and craters, the astronauts will have to become self-sufficient, building everything themselves and taking all the food and oxygen they will need to keep them going in the meantime. This means ten years of learning everything from plumbing to medical care.
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Luckily, learning is what drives Ms Lieu more than anything else. "I'll finally have time to read all those textbooks," she says.
Currently studying for a PhD in astrophysics at Birmingham University, becoming an astronaut would make Ms Lieu's childhood dream a reality. "It's exciting because we all have so much to learn from each other," she said, speaking of her future co-inhabitants.
"I'd start an educational system and make it my aim to inspire people to take an interest in science."
Ms Lieu, who lists pilates, rock climbing, fashion and photography as her non-science hobbies, has already made headlines for admitting that she'd like to be the first to have a child on Mars, but with so much risk in keeping herself alive, doesn't she think that bringing a baby into such a hostile natural environment might be selfish?
"I think it would be really exciting to have a child because it would be the first real Martian. I don't know what race or nationality it would be because there are no countries on Mars - yet."
Like everything the participants would experience on Mars, giving birth would be an experiment.
"There's not really been much research into it" Ms Lieu said, "Nobody knows the effects low gravity would have on a foetus. Also, the high levels of radiation would make the guys infertile. So I don't know if it would work but if you want to start a colony... you have to reproduce."
Members of the Mars One project have been warned that the prize is strictly a one-way ticket. Launching into space in groups of four, each trip will cost around $6bn, and a return journey is considered economically and practically unfeasible due to the lack of infrastructure on Mars.
But Ms Lieu is optimistic about the possibility of a return to Earth. "Technology is advancing so quickly, so who knows what might be possible later on. NASA are launching their own mission an extra ten years down the line, so maybe I could catch a ride with them..."
That said, she's not so sure she'd want to come back. Aside from the fact she would be physically disabled back on earth after years of muscle and bone wastage, the PhD student received her first hate mail this month.
"Somebody wrote to me saying: 'Why do you dye your hair like that? I hate people like you....' This person also tweeted me some horrible things. They compared me to a mass murderer in the US who had gone round shooting kids in a school... What did I do to deserve that?"
Some aerospace experts have dismissed Mars One - which is being run by a Dutch not-for-profit organisation - as a gimmick that will never get off the ground.
But Ms Lieu is confident that - if the spacecraft do set off as planned - a model community could be built on Mars.
"There'd be no legal system or parliament so it would be really fascinating to see how we work out our lives."
With no rules, might there be chaos? What worries Ms Lieu most is that the habitations designed for the astronauts are inflatable. "They're built to be light, but what if they burst."
Even if I don't make it to Mars this time, I'll be happy just knowing that the project is getting people excited about science. To be curious is to be human and that's what it's all about."
