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?'"

Mars One's founders and would-be astronauts discuss plans to go a one-way trip to the Red Planet in 2023.

More about missions to 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.