by Peter Merlin, special to Aerotech News
“We’re going to Mars,” President Donald Trump told reporters at a White House press conference in 2019.
Maybe not, according to astrodynamicist Daniel R. Adamo, who believes there may be no compelling reason to put human bootprints on the Martian surface anytime in the foreseeable future.
“We should pioneer on Mars only if it’s possible and ethical to thrive there economically and biologically,” Adamo said at a recent e-Town Hall meeting hosted by the Los Angeles and Las Vegas chapter of the American Institute of Aeronautics and Astronautics, held via Zoom on Aug. 8, 2020. He believes Mars has become more of a “socio-cultural destination” whose suitability for human exploration and pioneering is based on more than a century of fictional literature and poorly informed research since the beginning of the Space Age.
Adamo, a recognized authority in human spaceflight operations, retired in 2008 following 29 years as a contractor at NASA Johnson Space Center in Houston, Texas, where he supported 60 Space Shuttle missions from the Flight Dynamics Officer console in Mission Control. Since then he has been engaged in astrodynamics research, consulting and outreach for such clients as NASA, the Review of U.S. Human Space Flight Plans Committee, Jet Propulsion Laboratory, and the Keck Institute for Space Studies.
He is quick to admit that despite frigid temperatures and a thin, un-breathable atmosphere, Mars has long been the most compelling of our planetary neighbors. This phenomenon began, he says, in 1906 when astronomer Percival Lowell published a book that described the crisscrossing lines he observed on the red face of Mars as water-filled canals, possibly having been built by intelligent beings to transport water from the polar regions across the planet’s dusty landscape. This colorful image inspired Edgar Rice Burroughs to author a series of popular pulp novels, starting in 1912 with A Princess of Mars. According to Adamo, it was “the adventure and romance of these stories” that fired the human imagination and inspired a yearning to go to Mars. Science fiction writer Ray Bradbury penned a collection of stories, published in 1950 as The Martian Chronicles, suggesting that colonization of Mars was nothing less than humanity’s destiny.
The dawn of the Space Age brought such dreams closer to reality than ever before. Adamo said famed rocket scientist Wernher von Braun spent much of his time at White Sands Missile Range in the late 1940s considering the problem of sending humans to Earth’s nearest planetary neighbor. Published in 1952, Das Marsprojekt, offered the first technically comprehensive design for a human expedition to the Red Planet, and boldly suggested a provisional launch date as early as 1965.
The red hills of Mars
A series of robotic probes visited Mars beginning in the early 1960s but the first images returned in July 1965 showed a dead world, its rocky surface gouged by craters and jagged canyons. Even the polar ice caps were composed mostly of frozen carbon dioxide. Nevertheless, Mars remained a source of wonder. Of all the planets in the solar system, it is the one most similar to Earth.
Moreover, evidence suggests that Mars was once covered largely by water and was warmer, with a thicker atmosphere, offering a potentially habitable environment.
Describing images returned from the Martian surface by the robotic rover Curiosity in 2012, Adamo exclaimed, “It looks like home!”
Indeed, many of these pictures show a desert landscape that closely resembles parts of the American Southwest, North Africa, Antarctica, the Middle East or Southwest Asia. Adamo says this likeness is misleading.
“The thin Martian atmosphere provides no shielding against cosmic radiation,” he explained. “Exposure inside above-surface habitats, space suits, and unpressurized rovers would provide inadequate radiation shielding to support 500-day duty tours, let alone multi-generation pioneering.”
Additionally, the rusty soil, composed mainly of magnetic iron oxides, clings to any surface with a slight electrostatic charge, including solar panels and motors. This is more than just a hazard to machinery and electronics. The Martian sky typically has a rosy hue due to suspended dust particles, which also contain carcinogenic compounds such as hexavalent chromium and toxic perchlorates that affect the human thyroid gland.
Adamo said extraordinary measures would be required to exclude dust and soil from the interior surfaces and atmosphere of habitat modules. Future explorers would do well to remember the experience of Apollo astronauts, who described smelling and tasting moon dust after removing their helmets inside the lunar lander after each surface excursion.
Those are only the problems awaiting humans on the surface, Adamo said. The journey to and from the Red Planet poses an equally large set of obstacles. The orbits of Earth and Mars align optimally only once every 26 months. Even under ideal circumstances, transit time between the two planets would take months, and any meaningful mission would last at least a couple years if not longer. Mission planners need to address the need for shielding against cosmic radiation, as well as for providing sufficient supplies of consumables — energy, oxygen, food and water — for the duration. New technologies are required to develop a Mars lander capable of surviving the plunge into the Martian atmosphere and gravity well and making a successful soft landing. “The one-ton Curiosity rover represents the current state of the art for the mass that we can land on Mars,” said Adamo. A lander carrying a crew and supplies would be much heavier.
Reduced gravity entails another set of challenges. Millions of years of evolution have optimized humans to live under Earth’s gravitational conditions, and astronauts living in microgravity during long-term space flights have returned with noticeable loss of bone and muscle mass. During transit to Mars this could be offset through the use of rotating habitat modules to simulate Earth-normal gravity. There is no practical way to do this on the Martian surface, where gravity is only 38 percent that of Earth. Additionally, getting back home following a Mars mission will involve substantial acceleration and deceleration that will expose crewmembers to high g-loads following their extended low-g sojourn.
Explorers and pioneers
According to Adamo, human activity in space can be divided into two categories, exploring and pioneering. Exploring entails a survey of foreign territory such as Lewis and Clark’s Corps of Discovery expedition across western North America in the early 1800s. Pioneering involves putting down roots for a multi-generational occupation of foreign territory, as with the Pilgrims in 1620.
“Exploration is a big part of NASA’s charter,” Adamo said. “Pioneering is not.”
He suggested the most logical approach would be to explore the Martian surface with robots under human control from a remote location such as a subsurface base on Deimos, the smaller and more distant of two moons orbiting Mars. Like Earth’s moon, Deimos is tidally locked with its parent planet, always presenting the same face toward the Martian surface. At an orbital distance of slightly under 15,000 miles it is close enough to facilitate near-instantaneous remote operation of robotic rovers, yet far enough away to allow observation of 98 percent of the planet’s surface and allow line-of-sight communications for 60 continuous hours at a time. The gravitational pull of Deimos is slight, making landing easier than on Mars, and the moon is large enough for construction of a subsurface rotating habitat to provide artificial gravity for inhabitants. Power-generating solar panels positioned at the poles would receive almost perpetual sunlight.
Mars, says Adamo, has become widely accepted as the ultimate 21st century pioneering destination in space. “Unlike exploring,” he explained, “pioneering must be conducted by humans in situ, and ultimately return sustained profits.
“Historically, human pioneering is usually undertaken for compelling reasons,” he continued, such as to escape from war, starvation, persecution and pestilence. It may also represent territorial expansion motivated by overcrowding, limited opportunities, poverty, or a desire to exploit resources. That has been the model on Earth but the reasons for pioneering in space are relatively abstract. Adamo noted that there is no predictable threat to widespread survival on Earth for the foreseeable future, nor any exploitable resource compelling enough to start a “Gold Rush” in space. Even if such resources were identified, he argued, they would be more safely and economically exploitable using robotic tools. Besides posing unnecessary risk to human life, the energy and consumables requirements for sustaining a mining colony, for example, would be prohibitive.
The “undiscovered country”
Again, Adamo offered an alternative. “Current knowledge of the ‘undiscovered country’ within our solar system suggests that numerous small bodies such as near-Earth asteroids represent humanity’s best hope for pioneering off Earth in this century,” he said. As of October 2014, there were more than 11,500 known NEAs in the inner solar system. “Over 3,100 of these are more accessible than Mars,” he added, noting that they can be reached sooner and more easily than can the Red Planet and are guaranteed to furnish ample opportunities to learn more about the nature and origins of our solar system and our home planet.
Those who disagree with Adamo include a growing number of thinkers and technologists who advocate development of a space-faring and multi-planetary civilization, given the increasingly precarious nature of our existence on Earth.
“I think there is a strong humanitarian argument for making life multi-planetary, in order to safeguard the existence of humanity in the event that something catastrophic were to happen,” Elon Musk, founder and CEO of transport services company SpaceX, said in a 2014 interview with online publication Aeon.
Musk hopes to see thousands or even tens of thousands of people living in a city-like colony on Mars as early as 2040. His stated goal is to increase the colony’s size until it exceeds one million people, a sufficient number — he hopes — to “recreate the entire industrial base” for a sustainable civilization. This is imperative, he believes, to ensure the long-term continuation of our species, which is currently at the mercy of a fragile global ecosystem with limited resources that can easily fall prey to an asteroid collision or some other unforeseen cataclysmic event.
Frank Stratford, founder of the MarsDrive Consortium, an international nonprofit organization that champions private-sector Martian colonization, agrees. “We want to go there to see if we can find evidence of life, a second Genesis, and if we don’t find it, we want to establish new life on Mars — our own,” he wrote for The Space Review in 2009. “For the first time in history a species on Earth has the knowledge and technology to ensure its own survival by seeding life on new worlds,” he added. “If there is a planetary crisis, such as the asteroid impact 65 million years ago that wiped out the dinosaurs, and we do nothing, then we will have lost it all.”
Adamo doesn’t believe we are ready to take this step. “We should continue to explore the surface of Mars robotically from Earth or from Mars orbit; if current or fossilized life exists there, it will be easier to detect and less likely to perish if humans are not present.”
He recommends making greater efforts to study human adaptation to reduced gravity in low Earth orbit with rotating habitats and developing routine interplanetary transport for humans and cargo. “We should continue to search for and explore NEAs and comets; more successful pioneering can be done at less risk and expense on small bodies than on the surface of Mars.” More important, the technology that will allow humans to live and thrive on the Red Planet is not yet available. “There’s nothing out there that’s viable, yet,” he said, noting that the road to Mars “is still a long, hard row to hoe.”