Are We Ready for Mars?

What will it take to send astronauts to Mars—and bring them home safely?

If humanity's future lies among the stars, a voyage to Mars is our next giant step. For the astronauts brave enough to venture so far from home and into such an extreme environment, the journey will be the ultimate test of endurance—of their bodies and minds, and the materials and technologies developed to protect them. Many of the risks they'll face, both physical and psychological, remain unknown or understudied; mitigating the dangers is a challenge that's equally as demanding, and fascinating, as designing the rockets and landers that will ferry them.

A Martian journey will take the better part of a year. As days tick on into months, the crew will be increasingly on their own. The ever-widening distance will delay communications with Earth, slowing emergency troubleshooting, including medical advice. We understand how astronauts' bones, muscles, eyes, and immune systems respond to several months in low Earth orbit, but no one knows what kind of toll the much longer and distant journey to Mars will take. On arrival, Mars will test the team with toxic soil, dangerous radiation levels, and low gravity, among many other factors. As the astronauts face the dangers of this new world, they'll also confront the stresses of prolonged isolation, unsettled circadian rhythms, and the constant strain of life in a closed, high-risk environment with little privacy—one with no option for resupply or rescue.

Biomedical engineer and human spaceflight expert Mark Shelhamer guides readers through—and beyond—the available data to the research and planning that's underway for deep space voyages—showing how medicine, engineering, mission operations, and artificial intelligence must be integrated to make these explorations successful. He argues that the traditional, siloed approaches to human health that got us to the Moon, and have kept us aboard the International Space Station, won't be enough for the Red Planet. What Mars will demand instead is intense resilience—of the crews' stamina and risk management skills, and of the spaceship's sustainable bioregenerative ecosystem—crafted to support the mission's goals, provide comfort, and cope with crises. Are We Ready for Mars? offers a rare look at what it will truly take to reach this storied planet—and how those efforts might then transform the ways we approach human health on Earth.