The Mars One project has attracted significant attention since it was announced - the mission is "to establish a permanent human settlement on Mars in 2023".
Over 150,000 people have already registered their interest in becoming the first human beings to live on the Red Planet; the catch is that none of the first batches of volunteers is expected to return to Earth.
However, experts now say the whole deal could be nothing but a "huge publicity stunt".
Mars One expects to launch its first shuttle (carrying two men and two women) in September 2022. The project has declared itself a not-for-profit agency and is headed by a Dutch company, whose creator and chief executive, Bas Lansdorp, expects funding to come from a reality television show documenting the colonisation of Mars.
"They're doing very well to get the public fired up about going and some time in [the] next decade or two we might see a commercial model ... but in the current form it's unlikely to succeed," Dr Adam Baker, an expert in space engineering from Kingston University, has said.
"There are a number of issues with Mars radiation. It doesn't have the same level of atmosphere to protect you from things like solar flares, dust is a problem, how toxic it is to human life in the long run? We don't know enough about that," he added.
Eager volunteers from all around the world, including countries like China, Brazil and India, have applied to take part in the project and paid an average of £17 in registration fees. Registration closes on Saturday.
However, not everyone is pessimistic about Mars One's chances. Dr Michael Martin-Smith, head of The Hull and East Riding Astronomical Society, believes the execution of the Mars One project will be difficult but not impossible.
"There will be rugged conditions with an inflatable habitat. Every rocket that lands with a crew will bring an empty stage, it won't be dead metal, it will be useful. They can extract radiation protection which is another big issue -are we going to get fried living there? Yes, if we live out there in a swimsuit on the surface, but if you build a nice igloo-type structure using Martian soil radiation protection can be created," he said.