On September 29, 2017, SpaceX CEO Elon Musk took the stage at the 68th International Astronautical Congress in Adelaide, Australia. Musk spoke about his company's plans for interplanetary travel and his belief in humanity's future as a multi-planet species.

His proposed first stop: Mars—sooner and cheaper than might be expected. In front of the assembled international audience of space enthusiasts and industry leaders, Musk boldly announced that SpaceX would reach the red planet by 2022.


Concept art for a SpaceX spacecraft on Mars.

This was not the first time the technology entrepreneur had made such bold pronouncements in front of the IAC crowd.

A year earlier, at the 67th IAC meeting in Guadalajara, Mexico, Musk had revealed that he had built his vast business empire primarily in order to make colonization of other planets possible, and presented a compelling plan for how to get to Mars. His glimmering visions of a terraformed planet, clean, orderly Martian settlements, and low estimated ticket price stoked his audience’s breathless desire to venture into the cosmos.

However, in addressing questions from the audience, Musk evaded practical questions such as who ought to make the dangerous first trips and how he expected to handle the problem of human waste. His focus on innovation reflects a current surge in enthusiasm for triumphant technological solutions to local- and global-scale problems and a longstanding disdain for the mundane and messy.


Elon Musk unveiled the Dragon V2, a spacecraft designed to carry people into Earth’s orbit and developed through a SpaceX and NASA partnership, in 2014 (left). Concept art for the Mars Excursion Module in a 1964 NASA proposal (right). 

Nearly half a century has passed since human feet last touched the surface of another celestial body. In the time since astronaut Eugene Cernan’s final steps on the Moon, we’ve sent uncrewed spacecraft near and far—to planets, moons, asteroids, comets, and dwarf planets, even to the very edges of the solar system. Human explorers, however, haven’t ventured beyond low-Earth orbit since 1972.

That hasn’t stopped dreamers and the practical-minded alike from contemplating what our next steps into the mythical final frontier should be.

As our closest neighbor and host to a bevy of robotic spacecraft that have gone before, Mars is a popular destination among those who yearn to make new footprints on an untrammeled world. Even before the Moon became the established finish line of the Cold War Space Race, leaders of the American and Soviet space programs envisioned Mars as humankind’s first stop in exploring the cosmos.

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Astronaut Eugene A. Cernan on the moon in 1972 (left). Mars in 2003, when it was only 34,647,420 miles from Earth—the closest the two planets have been in 60,000 years (right). A panoramic image of the Mars Pathfinder mission taken from its landing site in 1997 (bottom). 

U.S. federal plans for planetary exploration have waxed and waned since the days of NASA’s Project Apollo, during which American men traveled to the moon and back nine times from 1963-1972. Following legislative wrangling over the proposed Asteroid Return Mission during the Obama administration, Donald Trump resuscitated George W. Bush’s promise to return to the Moon and move on to Mars—and like his predecessor, he did not offer concrete plans for doing so.

However, with the rise of a thriving private space industry, presidents and legislators no longer hold exclusive authority over extraterrestrial planning. Tech billionaires, aging Apollo astronauts, and nonprofit space enthusiast foundations have lately emerged as practical power players.


The 2015 mission logo for the OSIRIS-REx mission (left). Concept art for the OSIRIS-REx Capsule returning to Earth (right).

Musk and Blue Origin CEO Jeff Bezos have both declared Mars a target for their burgeoning aerospace businesses. In 2015, the nonprofit Interplanetary Society successfully launched a citizen-funded propulsion system that uses solar energy as a kind of cosmic sail. Enthusiast organizations from the Mars Society to Apollo 11 astronaut Buzz Aldrin’s ShareSpace Foundation all promise that with a little imagination—and money—humans will reach Mars within the next few decades.

While the thrill of exploration yielded “flags and footprints” on the Moon, it takes more than a few small steps to turn a frontier into a colony. If humanity is to become a truly multi-planet species, we must develop both the will and the means to go and to stay put.

Getting there is only the first challenge. Figuring out what to do once humans arrive is much harder.

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Jeff Bezos (third from left), the Founder of Blue Origin, and Lori Garver (forth from left), NASA Deputy Administrator, in front of a composite pressure vehicle at the Blue Origin headquarters in 2011 (left). Elon Musk speaking at a Mars Society Conference in 2006 about the Falcon 9 launch vehicle and Dragon manned spacecraft (top). Apollo 11 Astronaut Buzz Aldrin in 2016 at a preview of the Kennedy Space Center Visitor Complex exhibit on Mars (bottom).

Mars as Empire and Utopia

The yearning to homestead other worlds isn’t anything new. The same desires that motivated European imperial pursuits and Anglo-American westward expansion in centuries past underpin many 20th-century arguments for extraterrestrial empire on the “final frontier.” Innumerable novels and movies feed a mainstream audience hungry for imaginary scenarios in which humans travel to other planets, and wonder what we might do once we get there.

In books and films, tales of tragic conquest are as common as fantasies of brighter futures in which humanity corrects the wrongs committed on Earth. Writers including Ray Bradbury and Sun Ra have even imagined radical futures of racial justice through the establishment of extraterrestrial black communities. Space is the place where the righteous of humanity may build new utopias and leave behind a ruined Earth.

Ray Bradbury’s The Martian Chronicles (1950) is collection of science fiction short stories about the colonization of Mars by humans fleeing an environmentally devastated Earth and coming into conflict with aboriginal Martians (left). The film poster for Sun Ra's Afrofuturist science fiction film, Space Is The Place (1974), (right).

During the late 19th century, astronomer Percival Lowell studied Mars from his observatory near Flagstaff, Arizona. He concluded that intelligent creatures had constructed canals to carry water across the surface of Mars, an idea that remained popular until 1965 when the first photographs from the Mariner 4 probe revealed a waterless, lifeless planet.

In subsequent decades, robotic orbiters, landers, and rovers have mapped the surface of the planet, conducted remote experiments, and even taken famous, red-tinged selfies. A fleet of spacecraft have successfully made the journey, from the twin Viking landers of 1976 to the ExoMars Trace Gas Orbiter that reached Martian orbit in October 2016.

Each spacecraft has been designed to protect the planet from being “seeded” with Earth microorganisms. Data from these missions have led scientists to determine that, while no life appears to exist on Mars, abundant water does.

Astronomer Percival Lowell at his Flagstaff, AZ observatory in 1914 (left). A photograph of craters on Mars taken by Mariner 4 in 1965 (right). The first “clear” image transmitted from the surface of Mars by Viking 1 in 1976 (bottom).

Perhaps this very lifelessness has made Mars that much more appealing to would-be colonizers. With no living creatures to be subjugated, moral questions about taking over an entire world seem less fraught than if living, breathing Martians existed.

Indeed, ecologists and environmentalists of the 1960s and 1970s enthusiastically studied extraterrestrial colonization largely because of this apparent lack of moral ambiguity.

During this time, as astronauts prepared to take the first steps on the Moon and environmental movements gained steam around the world, scientists like Edward Wilson and Eugene and Howard Odum considered whether more orderly worlds might be created on other planets. NASA even funded studies by ecologists to determine how to build self-sustaining “life boats” in orbit as a stepping stone to extraterrestrial colonization.

Leaders in current space culture express their desire for permanent colonization of other planets either to escape a dying earth or as a means to improve life on earth.


Concept art for a Mars settlement with a cutaway view of an underground habitat area for growing food (left). A fictional Mars tourism poster commissioned by SpaceX in 2015 (right).

Some, like Musk, see colonies on Mars as the only way to ensure the survival of life as we know it. Their worry is growing as the physical evidence of climate change continues to mount and American political will fails to rise to the challenge.

NASA Administrator Charles Bolden has also advocated interplanetary colonization but with a more distant doom in mind—noting that our Sun will eventually transform into a red giant star whose radius will consume Earth, Bolden argued that homo sapiens must become a multi-planet species to ensure its long-term survival.

Others, like Jeff Bezos, sees otherworldly colonies as sources for energy and raw materials to bolster Earth civilizations—a colonial vision in lockstep with imperial programs throughout history.

Buzz Aldrin sees permanent colonization as the only way to make scientific research on other planets affordable and sustainable—a perspective he likely gained after his 2.5 hours traversing the lunar surface in 1969.

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NASA Administrator Charles Bolden speaking to students in 2016 (left). Astronaut Buzz Aldrin during a lunar landing mission in 1969 (middle). Bolden congratulating SpaceX CEO Elon Musk after the first successful mission by a private company to carry supplies to the International Space Station in 2012 (right).

Planetary Analogs from Moon to Mars

As Aldrin knows, even getting off the planet requires immense investment of resources, capital, technology, and intellect. And expenditures by the federal government to support space travel seemed more plausible during the Cold War era than they do today.

Surviving for long periods on another world has yet to be attempted. It goes without saying that living any place other than the planet to which the human species has been perfectly adapted presents monumental difficulties beyond securing funding.

Cold War-era thinkers began to work out the challenges of extraterrestrial living before making the voyage. Several organizations took on the task of making Earth like Mars—creating what are known as planetary analog habitats.

Planetary analogs involve recreating the conditions of another celestial body on Earth. This has historically involved working in an ecosystem resembling the Martian landscape, building habitats that replicate the expected conditions of extraterrestrial living, and determining what parts of Earth might best survive and sustain life on another planet.

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Astronauts practicing microgravity techniques in NASA’s Neutral Buoyancy Lab at Johnson Space Center (top left). An astronaut and geologist in Arizona testing a lunar rover in 2008 as part of the Desert Research and Technology Studies program (top right). Members of the Mars Research Society practice near the Flashline Mars Arctic Research Station in 2001 (bottom left). The Human Exploration Research Analog at the Johnson Space Center in Texas is a modular, three-story habitat designed to simulate the isolation, confinement, and remote conditions of mission exploration scenarios (bottom right). 

Planetary analogs provide the opportunity to test out humans’ adaptability without having to leave the safety of planet Earth. These experimental attempts have ranged from geological training exercises to constructing large-scale Earth habitats. With each planetary analog experiment, the imagined realities of life on another planet shifted in place.

Will future “Martians” wear space suits and move from tiny habitat to tiny habitat? Will they be expected to tend entire ecosystems? Or will they oversee the wholesale transformation of an entire planet to mimic the familiar Earth?

Some of the first planetary analog experiments were designed to simulate what geologists expected astronauts might find upon landing on the Moon. NASA selected natural sites that resembled what the Moon looked like from afar. Astronauts trained at sites in New Mexico, Nevada, Alaska, Hawaii, and Iceland, each chosen for their strange geological features.


Members of the Apollo-14 team at the Craters of the Moon National Monument in Idaho in 1969.

During the mid-to-late 1960s, popular attractions such as the Grand Canyon, Sunset Crater, and Meteor Crater—not far from the Arizona observatory where Percival Lowell once studied Martian canals—provided geologists with opportunities to teach non-scientist astronauts how to evaluate rock strata in the field.

The aptly named Craters of the Moon National Monument in Idaho served as a useful site for astronauts to practice maneuvering and using new tools. The monument continues to be used as a test bed by planetary scientists.


Run by the Mars Research Society, the Mars Desert Research Station in Utah simulates Mars surface exploration habitats.

Where naturally occurring rocky features would not suit training needs, federal scientists made new ones. In 1967, the joint NASA-U.S. Geological Survey Astrogeology Research Program built a microcosm of the Moon into the rocky terrain of an extinct Arizona volcano by blasting holes in the ground to resemble lunar craters.

Astronauts wore space suits, collected soil samples, and drove a lunar module nicknamed “Grover” through the artificial moonscape that came to be known as the Cinder Lake crater field. Such analog sites allowed astronauts to practice a few small steps in a place that resembled the Moon before taking the 238,000-mile voyage.

As human planetary exploration waned after Apollo ended in 1972, robotic emissaries required similar sites on Earth to anticipate and practice maneuvering in places like the Martian landscape. Desert ecosystems have long provided useful “sandbox” trials for rovers.


NASA and the U.S. Geological Survey Astrology Research Program testing equipment in Nevada in 1972.

In addition to testing mechanical systems, Earthly analogs provided useful settings to drum up popular support for Mars missions. To celebrate the Viking landers’ trips to Mars, landing a few months apart in July and September of 1976, famous science popularizer Carl Sagan posed with a Viking model in Death Valley. The reddish hued sands and alien geological formations suggested what Viking might look like once it reached its destination.

These analogs rendered Mars more familiar to non-planetary scientists. When the Viking landers sent back their images, the landscape looked uncannily familiar, much like the deserts back home.

The Soviet and Russian space programs have notoriously found it difficult to complete successful missions to Mars. Each attempt since 1960 has failed.


Astronomer, cosmologist, and astrophysicist Carl Sagan posing in Death Valley, CA with a model of the Viking lander for his television series, “Cosmos.”

However, while the United States successfully launched and landed Viking spacecraft on Mars, the Soviet Union developed and tested closed life-support systems intended for future use by cosmonauts on other planets.

The Soviet BIOS program ran from 1965 with the construction of BIOS-1 through the mid-1980s with the operation of the BIOS-3 facility. With each subsequent BIOS structure, Soviet scientists increased the complexity of plant life used to exchange gasses with human occupants. The earliest experiments used algae, and later tests employed specialized growth chambers to cultivate vegetables such as wheat, beets, carrots, cucumbers, and dill.

BIOS-3 was constructed entirely underground in Krasnoyarsk, Russia, and supported its first fully enclosed human crew of two men and one woman in the winter of 1972 to 1973. Missions ranged in length from several months to a year. Researchers claimed that the BIOS project demonstrated that a habitat could successfully use food crops and other plants to uphold the exchange of oxygen and carbon dioxide necessary to keep human occupants alive in a closed system—the kind that would be necessary for a mission to Mars.


A mission patch for the Soviet Vostok 3 program in 1962 (left). The first American female astronaut, Sally Ride, aboard the Challenger Space Shuttle in 1983 (right).

Meanwhile, NASA continued to reach for human trips to Mars. Following the Challenger disaster in 1986, NASA recruited a committee chaired by Sally Ride, the first female astronaut, to contemplate ways to revive and refocus the American civilian space program. In addition to bolstering the shuttle program, continuing the space station project, revisiting the Moon, and supporting ongoing robotic exploration of the solar system, the Ride Report called for establishing an outpost on Mars.

Three years later, on the 20th anniversary of the Apollo 11 moon landing, President George H. W. Bush revealed his Space Exploration Initiative, which also promoted a return to the Moon and Mars.

These perennial calls for Mars colonization did not go into detail on the methods and plans for long-term settlement. None moved beyond initial grand announcements. Even our robotic emissaries stayed home—two decades elapsed between the Viking landings and the 1996 launch of the Mars Pathfinder mission. For 20 years, humankind steered clear of the red planet.


In 1989, President George H. W. Bush announced his Space Exploration Initiative in front of the National Air and Space Museum at the 20th anniversary celebration of the Apollo 11 Moon landing.