NASA / STScI

Mars looms large in a Hubble Space Telescope photo - and in the imaginations of those who have signed up for a one-way trip to the Red Planet. "It's not that I'm trying to get away," says 18-year-old Kayli McArthur, one of tens of thousands of applicants. "It's like I'm trying to strive for something more."

A one-way trip to Mars sounds like something you'd wish on your worst enemy — so why would more than 78,000 people from around the world pay up to $75 for a chance to die on another planet?

"I can say I have an ulterior motive," said David Brin, who has written more than a dozen science-fiction novels — including "The Postman," which was turned into a Kevin Costner movie in 1997. "I'd get a lot of writing done, and it might be memorable."

As a master of hard science fiction, the 62-year-old Brin knows better than most applicants what the first Red Planet settlers would face if they're sent off in 2022, as the Dutch-based Mars One venture has proposed.

The settlers would have to be sealed up in habitats, protected from harsh radiation, supplied with machine-made air and water, and nourished by whatever food can be grown on a cold, barren planet. They'd have to keep their sanity, millions of miles away from their families and Mission Control. Worst of all, they'd have to face the fact that there's no guarantee of ever going back.

Will this scheme actually work? "I give it a low probability of happening," Brin said, "and I don't consider it to be the most responsible thing I've ever seen."

Nevertheless, the venture has an attraction for Brin and tens of thousands of others, The ages of those listed in Mars One's database range from 18 to 71. All those applicants are facing a long road even before the first four-person crew gets off the planet. Mars One is accepting applicants through Aug. 31. The field of applicants would first be whittled down by panels of experts. Then they'd undergo trial by reality TV, followed by years of training.

"This may sound crazy, but it kind of reminds me of 'The Hunger Games,'" said Kayli McArthur, an 18-year-old student who's one of the youngest Mars One applicants. "It's cool that it would be televised, but that's not my whole thing."

On the other end of the age spectrum, 71-year-old psychiatrist Sanford Pomerantz is a little surprised that it's taking this long to get something like Mars One off the ground. "I thought by now we would have colonized Mars," said Pomerantz, who's currently the oldest applicant on Mars One's list.

So what's the appeal of Mars One? It's too early for Brin, McArthur and Pomerantz to give a lot of thought to their adventure on Mars, let alone their death on Mars. Instead, they're focusing on the adventure here on Earth. Here's what's behind their thinking:

Mars One

Click on the image to go to David Brin's Mars One application video.

David Brin: 'My main purpose is the conversation'
Brin sees Mars One as just one of a number of ventures aimed at expanding humanity's frontier, ranging from Virgin Galactic's suborbital space tours to Golden Spike's moon missions. "It's emblematic of the new era that we're about to enter at long last — what I call the barnstorming era," he said.

Like the daring airplane fliers of the 1920s, these 21st-century space barnstormers are willing to take bigger risks in hopes of providing bigger thrills — and eventually, earning bigger payoffs. The Mars One project is "a great way to get the discussion going," Brin said.

"You have to assume that it may not work, and that there will be a statue of you on Mars someday," he said. "I'm aware of the tradeoffs, and I'm willing to explore it further, but largely my main purpose is the conversation. We've got to be talking about how we can be a more exploratory people — a more interesting people, if you like."

Brin doesn't doubt that Mars One will find plenty of qualified (and interesting) people willing to take the risk.

"People who cannot imagine any sane person making that choice simply aren't envisioning the wide range of human diversity," said Brin, who has three children in school. "Consider what I told my family. By the very earliest date that Mars One might launch, I expect to be a spry 75-year-old whose kids are already successfully launched, and who might spend a few years doing something truly remarkable."

Even if it means dying on alien soil? Brin isn't completely sure he'd go that far, but he's willing to bet that others would.

"I think you'll find tens of thousands of people who, under those circumstances, will at least ponder it seriously," Brin said.

Mars One

Click on the image to go to Kayli McArthur's Mars One application video.

Kayli McArthur: 'I'm trying to strive for something more'
McArthur, a freshman at the University of Arizona, is one of more than three dozen 18-year-olds on Mars One's list of applicants. Ever since she applied, she's been hearing that she has her whole life ahead of her, so why would she want to leave it all behind for Mars?

"Being young doesn't make me want to do it any less because I have my whole life ahead of me," she said. "It makes it more exciting. ... I love all my friends, my guy friends, my family. It's not that I'm trying to get away. It's like I'm trying to strive for something more."

She has long dreamed of going into outer space, and she figures that her future degree in materials science would come in handy for creating the first interplanetary settlement. "Going to Mars, there are so many opportunities for that," she said. 

So far, her family hasn't stood in her way. "My family jokes, like, 'Oh, Kayli, have your fun with it,'" she said. If the selection process gets more serious, she suspects she might face more resistance from her parents. But not from her grandfather.

"My grandpa is a retired three-star [general] in the Air Force," she said. "We were talking about it. I get really worked up and excited, and he was talking about it, too, and being realistic about it. He said, 'That would be so cool if you were able to do it.' ... I know my grandpa would totally support me."

Mars One

Click on the image to go to Sanford Pomerantz's Mars One application video.

Sanford Pomerantz: 'Grandpa is going to Mars!'
Pomerantz is old enough to remember when the idea of sending people into outer space seemed as far out as the idea of sending people on a one-way trip to Mars seems now. One of the books that made an impression on him in grade school was Robert Heinlein's "Red Planet: A Colonial Boy on Mars," which was published in 1949.

"I started as a physics major in the university, but then I got accepted into med school and changed directions," he said. At the age of 71, he's still a practicing psychiatrist in Topeka, Kan. But he's also still holding onto that boyhood dream of spaceflight.

"The Mars thing is exciting, because I hope it'll stimulate people to get interested in space. ... And I hope it has the secondary effect of stimulating science education, especially in the U.S.," he said.

Just as McArthur believes that Mars will need a materials scientist, Pomerantz believes the crew will need a psychiatrist. "Psychologically, it's going to be an interesting challenge, but human beings are very adaptable," he said. "It'll be exciting to go to a whole new world. It'll be a major step in human evolution."

If Pomerantz ends up being selected for the first Mars crew, he's likely to become not only the oldest human to head for the Red Planet, but the oldest human to go on any space mission. (The current record-holder is John Glenn, who flew on the shuttle Discovery when he was 77 years old.) For now at least, that prospect doesn't faze Pomerantz's three children and two grandchildren. "The grandchildren are excited," he said. "It's like, 'Grandpa is going to Mars!'"

Pomerantz became a certified scuba diver just two years ago, and he still expects to be in good physical and mental shape for liftoff in 2022. "Remember, age is a state of mind," he said. "Chronologlcally, I may be 71. ... But psychologically and physically, I'm definitely in my 20s. I look in the mirror and say, 'Who's that old guy?'"

More about missions to Mars:

• Inspiration Mars: So crazy it just might work
• Buzz Aldrin envisions US leading way to Mars
• Cosmic Log archive on Mars

David Brin's latest science-fiction novel is "Existence," which is set in the latter part of the 21st century and involves matters way beyond Mars.

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the NBC News Science Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with NBCNews.com's stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Organizers of the Dutch-based Mars One project opened up their website on Monday to take applications for a one-way trip to Mars in 2022. 

That's right: These astronauts won't be coming back. The idea is to jump-start a permanent settlement on Mars, with more supplies and settlers arriving every couple of years.

The organizers say the $6 billion cost for the first landing would be covered through reality-TV deals and merchandising, but they skirted pointed questions about the plan's financial feasibility.

Mars One co-founder Bas Lansdorp compared the non-profit venture to the London Olympics, which reportedly brought in $3.8 billion in revenue for last summer's 17-day spectacle. "If you can make $1 billion per week just by having a large audience in the entire world, then suddenly $6 billion doesn't sound like so much anymore," he said.

He declined to provide a detailed breakdown of the costs during Monday's news conference in New York, largely because he didn't want to give away any competitive information about the talks being conducted with potential suppliers. "It would be very stupid for us to give the prices that have been quoted per component," he told reporters.

He acknowledged that the mission's financial aspects posed the greatest challenge. However, he said the drama surrounding Mars One's plan to send four-person crews to Mars, with no promise of return, was "exactly the greatness that makes it possible to finance this."

"It's easier to finance a mission to Mars than to finance a mission to the moon," he said.

Thousands register interest
There has certainly been lots of enthusiasm for the mission: Lansdorp said Mars One has received more than 10,000 emails from more than 100 countries around the world, voicing willingness to sign up for a one-way ticket to the Red Planet. Starting Monday, anyone 18 or older can formally apply — provided that they pay an application fee. Lansdorp said the fee ranges from $5 to $75, depending on the standard of living for the country of residence. U.S. residents, for example, will be charged $38.

Each applicant will have to submit a one-minute video explaining why he or she should be among the first humans on Mars. Applicants will be screened for physical and mental fitness, and will have to speak English. They should also be "mature and interesting," Mars One says. But chief medical director Norbert Kraft said there are no formal academic or professional prerequisites. "We will give the training," he said.

Mars One's business plan calls for the latter stages of the selection process to be broadcast on TV and the Internet. Twenty-four to 40 finalists would be chosen to go through years of training. At the end of the process, Mars One expects at least six crews to be ready for flight. Each crew would consist of two women and two men. Having six crews available would ensure against the possibility that someone gets sick — or gets "cold feet" — when it's time to fly to Mars, Kraft said.

The venture's time line calls for the first in a series of preparatory robotic missions to lift off in 2016. An exploratory rover would be sent to Mars in 2018, and another rover would head out in 2020 to get the chosen target site ready for human habitation. Eight robotic missions would be sent before the human crew sets out in 2022 on a seven-month cruise, Lansdorp said. The landing is currently scheduled for April 2023, "exactly 10 years from today," he said.

Organizers say the $6 billion raised through broadcast and marketing rights would cover costs through the first landing in 2023. Billions more would be required to keep the colony going and growing beyond that. 

Lansdorp said the project would be presented to international broadcasters at the Mipcom conference in Cannes, France, this October. He acknowledged that the time line might be delayed due to technical difficulties. "This will not be easy," he said. "There is lots of engineering and testing to be done before the first humans land." But he said the Mars One group is already in discussions with spaceflight companies including SpaceX and Paragon Space Development Corp. about the launch plans.

Grant Anderson, Paragon's senior vice president of operations, said his company was working on a concept design study that would be delivered to Mars One this summer. "The Mars One program is doing this right," Anderson said.

One of the potential scenarios would employ expanded SpaceX Dragon capsules for the missions, Lansdorp said. SpaceX's billionaire founder, Elon Musk, has repeatedly said it's technically possible to put humans on Mars in 10 years. There's already a "Red Dragon" plan for Mars landings, with an estimated price tag of $400 million or less per mission.

Reality check
Veteran rocket engineer Robert Zubrin, who is president of the non-profit Mars Society, agrees that Mars One's plan is technically feasible — but adds that it's incredibly challenging. "They have set a very high bar for themselves, and I'm not sure they have the resources," he told NBC News.

Former NASA mission planner Scott Hubbard, who is now a professor of aeronautics and astronautics at Stanford University, said landing on Mars safely ranked among the biggest challenges. "Anyone familiar with the 'seven minutes of terror' knows that getting anything substantial [to the Martian surface] is not a trivial issue," Hubbard said. Other challenges include weathering the radiation exposure and health effects of long-term weightlessness on the way to Mars; and truly being able to have astronauts live off the land once they get to Mars, with no possibility of heading back to Earth.

"It's certainly a bold concept, something that I don't know a government would ever contemplate," Hubbard said. He said the project could end up costing much more than the currently projected $6 billion.

The one-way nature of the Mars One trips didn't bother Zubrin: "There's nothing fantastical about that," he said. "We're all on a one-way trip to somewhere."

But Zubrin said another attention-getting trip, the Inspiration Mars plan to send a husband-and-wife crew on a flyby past the Red Planet in 2018, would be far less demanding. The price tag for that trip is thought to be on the order of $1 billion, and it already has the backing of millionaire space tourist Dennis Tito. A successful flyby in 2018 could conceivably generate interest in more ambitious missions, Zubrin said.

"If Inspiration Mars can do that, they will have significant credibility to raise large amounts of money to take humans to the Martian surface," Zubrin said.

When it comes to reality TV, money and the willingness to take on risks are the keys to success, said Hollywood producer David Krieff. He should know: Ten years ago, Krieff helped put pop singer Lance Bass through Russian cosmonaut training for a reality-TV project that would have sent him to the International Space Station. The project fizzled out when TV executives, potential sponsors and insurers got cold feet.

Krieff had some words of advice for Mars One's organizers: "I wish them luck, but I would say have the money in the bank — and most of all, have all the liabilities taken care of," he said. "The risks and the insurance and the money is a lot of work. These things are always more expensive than you expect."

More about missions to Mars:

• How to take a one-way trip to Mars
• Mars flyby in 2018? So crazy it might work
• NBC News archive on Mars

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

If you think you have the right stuff to help colonize Mars, you'll soon get your chance to prove it.

The Netherlands-based nonprofit Mars One, which hopes to put the first boots on the Red Planet in 2023, released its basic astronaut requirements on Tuesday, setting the stage for a televised global selection process that will begin later this year.

Mars One isn't zeroing in on scientists or former fighter pilots; anyone who is at least 18 years old can apply to become a Mars colony pioneer. The most important criteria, officials say, are intelligence, good mental and physical health and dedication to the project, as astronauts will undergo eight years of training before launch.

"Gone are the days when bravery and the number of hours flying a supersonic jet were the top criteria," Norbert Kraft, Mars One's chief medical director and a former NASA researcher, said in a statement. "Now, we are more concerned with how well each astronaut works and lives with the others, in the long journey from Earth to Mars and for a lifetime of challenges ahead."

Mars One plans to launch a series of robotic cargo missions between 2016 and 2021, which will build a habitable Red Planet outpost ahead of the arrival of the first four colonists in 2023. More settlers will arrive every two years after that. There are no plans to return the pioneers to Earth. [Mars One: 'Big Brother' on Mars? (Video)]

The organization will fund most of its ambitious activities by staging a global reality-TV event that follows the colonization effort from astronaut selection through the settlers' first years on Mars.

Mars One, which transitioned from a private company to a nonprofit late last year, has already received a number of inquiries from prospective colonists, officials said.

"Well before the official Astronaut Selection Program, we received more than 1,000 emails from individuals who desire to go to Mars," Suzanne Flinkenflögel, Mars One's communications director, said in a statement. "We are working hard to launch our selection campaign as soon as possible, to open the doors to everyone who aspires to do something tremendous in their lifetime."

Final astronaut candidates will be selected after review by Mars One experts and a global TV event. Those chosen will be employed by Mars One during their Earth-based training and for the length of their time on the Red Planet, officials said.

To learn more about the selection process, go to www.thenextgiantleap.com.

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