The £4bn project, founded in 2010 by engineer Bas Lansdorp, is set to recoup its costs by selling the broadcasting rights to the mission.

"The biggest media event in the world," said Paul Römer, the co-creator of Big Brother and ambassador of the project, on the Mars One website. "Reality meets talent show with no ending and the whole world watching. Now there's a good pitch."

But the mission has been met by more than its fair share of sceptics. Funding issues, technological hurdles as well as the psychological challenges the astronauts will come up against have all come under scrutiny.

As 22-year-old hopeful Thomas Eccles points out, "can you imagine how deranged and unstable I would eventually become? That would make for some impressive TV gold. But having 'been to Mars' on your CV has got to be pretty impressive, right?"

But a return to Earth to update CVs is far from guaranteed. Changes in bone density and circulation caused by Mars's gravity as well as the technical challenges involved in re-entering the Earth's atmosphere make a return seem unlikely. If there's a problem, a call for help could take up to 22 minutes to arrive at Earth, depending on the position of the two planets, and even then the fastest rocket would not arrive until six months later.

By 2015, 40 candidates will start their eight-year training programme where they will learn, amongst other essential skills, to deal with long periods of isolation.

Here, some of the hopefuls explain why they're prepared to leave friends and loved ones behind for the chance to establish life on Mars.

Erica Meszaros, United States

                Erica: 'As a non-astronaut the whole process of our current space exploration seems akin to strapping yourself to an explosive.'

Why did you apply for the Mars One mission?

I want to see the sun rise over a completely new horizon, in a completely new sky. I think that's worth any price. To me, the desire to explore a new world, a planet completely different from the one that every person who has ever lived has ever known, is intrinsic and essential to the human spirit.  Mars has been there, taunting us, for years. We've had the technology, we have the desire, and now it's time to finally go there.

The amount that we can gain from going to another planet it is just absolutely necessary.

How do you feel about leaving your family and friends behind?

It would be tough to have to say goodbye to my husband forever, tough in a way that hasn't really set in for me yet. We've been married for eight months and together we foster a number of pets. But he's always known that if space travel were an option, I'd be lining up, and he says that he would do everything in his power to get to Mars as well. That's at least comforting. My in-laws hate it, and my mom thinks it's a joke, but they're mostly concerned about losing the opportunity for grandchildren.

                Erica Meszaros as a child visiting the Kennedy Space Center

Won't you be afraid?

Of course I'm afraid but as a non-astronaut the whole process of our current space exploration seems akin to strapping yourself to an explosive. But it's not. There's science involved. And I'm sure that the more I know and the more I train and the more I prepare, that fear will go away. Although I'm not sure how I feel about being filmed for 24 hours a day, but I suspect that if anyone could pull off a tactful and interesting reality TV show it would be Mars One. 

You seem to have a lot of faith in the mission?

Sure, there are a little of things that still need to be finalised or figured out. But I can say that I am as certain as possible in my commitment to Mars One. It's hard to fully believe in the success of something that can't give you all of the answers right away.  But it's important to remember that Mars One isn't taking off tomorrow.  What Mars One has done is to put it's full faith and confidence in the totality of human ingenuity and creativity so that ten years from now we CAN get to Mars.  And I have a 100% confidence in humanity.

What one item from Earth will you make sure to take with you?

I have a stuffed animal of a mongoose that's been everywhere with me. My husband bought her for me when we were just dating, and ever since she's followed me to work conferences in Hawaii and internships in California. I'd love to take her to Mars, too.

Josh Richards, Australia

                Josh Richards: 'If there was one thing I could take to Mars it would be my semi-acoustic ukuele named Amanda. It has travelled around the world and has never failed to lift my spirits or those around me.'

What are you hoping to achieve by traveling to Mars?

I see it as the opportunity it is - an amazing chance to serve all of humanity by taking part in a project that will inspire generations to come. This isn't about what we might leave behind: it's about the potential for breathtaking scientific discoveries and to recognise our species' incredible potential if we simply work together. My friends and family recognise how important taking part in this is, how dedicated I am to furthering humanity's reach into space with Mars One.

Edgar Mitchell, the Apollo 14 Lunar Module Pilot, said that walking on the Moon gives you an instant global consciousness, an intense dissatisfaction with the state of the world, and a compulsion to do something about it, that international politics look so petty. I can only hope that by permanently colonising Mars we can serve as a reminder to everyone how fragile life is, and what wonders humanity is capable of when we realise how petty our differences really are.

Are you worried about who you might have to share the journey with?

I'm not worried about who I'd be sent into space with... but I am curious as to who they might put me in a trial habitat with! The 'reality TV' aspect of Mars One is a bit misleading - while the activities of the astronauts will be broadcast, the astronaut selection committee, Dr Norbert Kraft and Professor Raye Kass) have made it very clear they won't be selecting future Mars colonists for their screen presence. And for the final 24-40 who are selected for seven years of training, they'll be spending three months of every year in a trial habitat to find out how they respond psychologically to the environment, and who they work best with - when the time comes to actually go, the final team of four will be inseparably close.

What would you say to the skeptics that think the Mars One mission will never succeed?

Mars One is using entirely existing technology alongside some of the most respected astronautics professionals in the world, their astronaut application program has had overwhelming financial and emotional support globally. Elon Musk has stated repeatedly that it's the goal of his aerospace company SpaceX to land and colonise Mars in the next 20 years, and I believe they will be very close behind Mars One in doing that. Most of the pessimism comes from folks who think government space agencies, specifically NASA, are the only ones capable of leading the way in space exploration. Dennis Tito's company Inspiration Mars is sending a married couple on a free-return trajectory around Mars, without landing on it in 2018. The sad fact is that Nasa had the technology to go to Mars in the late 80's but proposed a plan that was far too expensive and amounted to little more than a flag-planting exercise.

If folks don't believe it will happen, that's fine, there's people who still believe the Earth is flat or 6,000 years old too.

Do you think you'll be able to cope with the mission's psychological demands?

I'm lucky enough to have the characteristics Mars One is looking for and I'm dedicated to be part in humanity's next giant leap! I've worked with the Australian army and the British Royal Marines and working for Damien Hirst, then as a full-time standup comic - I discovered Mars One after the 2012 Edinburgh Fringe when I started writing a new comedy show about sending people one-way to Mars! In January I left the girl of my dreams and moved back to Australia, knowing I could do more to promote Mars One's mission than I could in the UK.

Will anything make you change your mind?

The day they stop trying to colonise Mars will be the day I stop trying to help them do it! One of my biggest fears would be that if something did go wrong it might take another 40 years before humanity worked up the courage to try again.

Ben Pearce, Canada

Why go all the way to Mars, why not become a scientist or an astronomer?

I've spent a couple of years working in the software industry, sitting at my desk writing tedious code and I began to wonder: is this it? Life after graduation didn't quite own up to my expectations.

There are so many profound scientific questions that can be answered if we set out and explore the red planet, that I would be remiss if I didn't apply. If we were to find a fossil on Mars, in the lava tubes, dry river beds or the regolith - loose material covering solid rock - the implications would be mind-boggling. Life would no longer be able to be considered unique to planet Earth, which would change the whole world's perspective on how common life actually is. I am inspired by Mars One's willingness to attempt to make this adventure a reality, and something deep inside beckons for me being a part of it.

                Ben: 'What gets me through the idea of leaving my friends and everyone I love forever is the knowledge that this settlement is bigger than my relationships because it will have an impact on the entire planet.'

Do you think you're psychologically prepared to leave your friends and family behind?

What gets me through the idea of leaving my friends and everyone I love forever is the knowledge that this settlement is bigger than my relationships; bigger than anyone's relationships, because it will truly impact the entire planet. I will also build new relationships with my crew because after-all, they'll be my new family.

My mother is happy to have me stay near home forever, I'm sort of a momma's boy. She fears for my safety and would miss me dearly, but she's starting to come around when I explain to her that this would be a chance to contribute to the entire world's knowledge on a grand scale.

And how do you feel about being filmed? Are you worried about who you might be spending forever with?

I think Mars One will defy the most regular reality TV standards in that the crew won't be chosen based on their ability to cause controversy, but rather their ability to solve it and maintain harmony. After some time the filming would just be a part of everyday life. I imagine it is like getting to know someone; except instead of that person being real and capable of two-way conversation, they are a camera that just listens.

It is extremely important that they choose not only four psychologically stable but four people who get along and create a good team. That is what the eight years of training will help determine: which group can survive in isolation. I'm sure sometimes I may get annoyed by my crew mates, they would be aware enough to know I might just need a moment alone and I would do the same for them.

There are a lot of skeptics, do you think Mars One will succeed?

There will always be doubters but these are people who lack the will and the ambition to try. It's much easier to deem something impossible than it is to sit down and engineer solutions. Space adventure is the next logical step to advancing civilisation. We've always ventured from home with the desire for knowledge, and those decisions spurred the technological and societal revolutions that brought us to today.

I don't know if Mars One will make the 2023 deadline but we just need to get started and that is what Bas Lansdorp and Arno Wielders are doing with Mars One.

What would you want to say to the TV cameras and the millions of people at home before you jet off into space?

In some ways I'd want to be humorous and in others I'd want to be inspirational. Either, "Damn it, I forgot to pay my late fees at Limelight Video Rental" or "I'll see you when you get here."

Pamela Nicoletatos, Netherlands

                Pamela: 'Scepticism has been the catalyst behind great discoveries and advancements we have today.'

Many reality TV shows often choose people for their on-screen presence. Are you worried about this?

I think as far as what I have researched the crews will be chosen on merit, skill and whether or not they adapt positively during the testing. I get on very well with all sorts of personality types so I do not think I have much to worry about. I've home-schooled two sons and have relocated to many different places over the years and these experiences have given me a huge desire to experience diversity. It will help me to be a more understanding when interacting with my team mates.

How do you feel about leaving your two sons behind?

I have talked with my family in respects to this and honestly with both of my sons being in their 20's at that time they see no obvious dilemma. We are happy to know we can communicate via various forms which will be set up by Mars One and think that our relationships will still be strong and continue to grow even if Planets apart. My husband is my biggest and most loyal fan and will support me in anyway he can. He thinks it is a great endeavor and looks forward to watching the projects success!

So you think it will succeed?

There have always been skeptics when innovation, disruptive ideas or ideologies have challenged the norm. This will never in fact change but has been the catalyst behind great discoveries and advancements we have today.

What are you hoping to get out of the journey? I've always had a passion for space and scientific discoveries. Humanity is more than just Earth, or even our solar system, but rather a small fraction of what all the Universe holds. I hope to only inspire others to have an innate curiosity for adventure, discovery and a desire to see things outside of the box. I just honestly think it is an opportunity of a life time and would be a shame to pass up!

Rickard Feiff, Sweden

                Rickard: 'Columbus could have skipped going west and waited a few hundred years for satellite technology to tell him what's was out there. He did not wait, nor will (or should) we.'

Why do you think you should be one of the chosen four?

I've had a good, steady life here with several jobs, several good relationships. I'm a correctional officer in the Gothenburg jail, working with people that are in desperate need of positive contact and change. It is a great insight into the human mind and a chance to work with the betterment of ones fellow humans. I'll be able to live in a small community and look back on all the good things I did back on Earth and feel satisfied with my life. How could I expect anyone else to go to Mars if I wasn't ready to do it myself.

Do you have any reservations about Mars One overcoming funding and technological problems?

Well, the funding is a big problem. I agree. But they are getting more and more sponsors as time goes by. I would love to say that this is too big and important to fail, but the truth is that until they land at least one big TV sponsor money might be a problem. Do I believe they will succeed? Yes. Call it faith, but I do.

The technology we have right now is enough to go there. There will always be a better ship, a better engine or a better habitat invented in the next decade. But it's the same on Earth, there are better cars, transportation and houses built almost all the time, but we don't wait indefinitely to get a new TV because there might be a better one tomorrow. We go for what we want when we want it. Columbus could have skipped going west and waited a few hundred years for satellite technology to tell him what's was out there. He did not wait, nor should we.

How do you feel about being filmed 24-hours a day?

I don't really mind. I will be filmed and watched by people I will never ever have to meet. I will literally be a world apart from them. And the building I currently work in already film every move I make 40 hours a week so I am kind of used to it in a way.

Are you afraid?

Not really, space travel is not something new. Are there risks? Yes. Can something go wrong? Yes. But that can happen here as well. I can be hit by a bus any day, have a flight accident next time I go on a vacation. There is always danger in life. Sure, there is a bit more danger here, but there is bound to be with something new and with stakes this high. It is only natural, and the possibilities of it all clearly outweighs the risks.

I would miss the people I leave behind beyond words. It will break my heart to never see them again, to never hug my family again. But it will not stop me from going. Humans move, change locations, it's not new. I am just going a bit further away than most.

Most people treat my application as a bit of fun, but that might change if I actually proceed to the next round. I was married for a few years and I am still very good friends with my ex-wife, her new boyfriend is a big supporter of me going to Mars, how about that!

What will you say as you wave goodbye to the TV cameras on Earth?

'Today humanity leaves its cradle, to take its first steps out beyond the birthplace. We travel, not for us, but for all of mankind. To a new world. To new sights. To a future we all share.' I guess it is good for me that I have at least 10 more years to work on that speech!

Will you apply to travel to the red planet in subsequent Mars One competition rounds? Do you believe the mission can succeed? Share your comments the in thread.