Life on Mars: Cold, harsh and underground

Mars is over 140 million miles away — but that's closer than you think, says Stephen Petranek.

Petranek's new book is called "How We'll Live on Mars." It details the realities of life on the red planet, and the difficulties the first visitors will face when they land, which could happen as soon as 2025.

Petranek joined MPR News' Kerri Miller to discuss the dangers and promises that Mars holds.

Pascal Lee, director of the Mars Institute at SETI, also joined the discussion.

On the show: Life on Mars

Humans could land on Mars in the next 20 years

Petranek holds up SpaceX CEO Elon Musk as proof that humans will reach Mars in the near future.

"Eight years ago, [Musk] didn't have a rocket that worked, and now he's resupplying the space station," said Petranek. "In a year, he's going to reveal the architecture of a huge rocket, the Mars colonizer."

Musk publicly announced his intention to land humans on Mars by 2030. "He's really shooting for 2025," said Petranek.

Lee also believes such a feat is possible.

"There's no denying that we can get humans to Mars and we should within the next two decades," he said.

Life on Mars will be cold, harsh and underground

Living on Mars will be an entirely different feat than landing on Mars. The first crew will know it's likely a one-way trip.

"It really is a horrible, deadly place," said Lee. "The temperatures on average are minus 80 degrees Fahrenheit... Your blood would boil because the atmospheric pressure is so low. The radiation will kill you."

But Petranek is confident in humans' ability to establish a colony underground and avoid the dangers of radiation. The next step is changing the planet into a more hospitable place.

"In the long run, we will be able to geo-engineer Mars; it's called terraforming," said Petranek.

Using radical techniques, including orbiting mirrors that are 150 to 300 miles across, Petranek argues that humans can warm the planet and increase the density of the atmosphere, making it more like Earth. Such a process would take hundreds of years.

Lee remains skeptical.

"Yes, you could survive there, you could set up a colony, you could establish an underground world — all of these are 'coulds'," said Lee. "But the question really is, 'is it desirable?'"

Mars may end up like Antarctica

Sci-fi writers have been dreaming of large-scale colonies on Mars for over a century, and Petranek lays out how that dream could be a reality.

But what Lee envisions is more like the scientific outposts of Antarctica. The harsh conditions, he argues, will prevent a full colonization.

The planet will likely be the domain of scientists researching the atmosphere and any alien life forms they find there.

In space, there are no rules

Who owns Mars? No one, according to the Outer Space Treaty of 1967. No government can claim ownership of any celestial bodies — they are considered "the common heritage of mankind."

Petranek pointed out that the almost 50-year-old treaty may be challenged as mankind reaches farther than the moon. The red planet is a new frontier, and with it comes a sense of Wild West lawlessness.

"There are no laws, there's no law enforcement," he said. "There's going to be a lot of people on Mars a lot sooner than most people think and there's absolutely no regulation of what's going to happen."

Exploring Mars is not a substitute for taking care of Earth

In many a science fiction film, humans have abandoned Earth after using up the planet's resources. But simply abandoning one planet for the next isn't what Petranek envisions.

"We must take care of the Earth," Petranek said. "Number one is not going to Mars, number one is taking care of Earth."

Exploring and colonizing Mars is instead a stepping stone to larger journeys.

"We have to become a space-faring species if we're going to survive," Petranek said.

The sun will eventually explode, destroying the planet.

"People say its billions of years away, and they're correct, but it might take that long for us to get good at interplanetary travel," he said. "You go to Mars and you get good at learning how to build cities on other planets."