Fields of Study

Atmospheric chemistry; astronomy; biology; climatology; engineering; cosmochemistry; global physiography; astrobiology; cartography; biogeophysics; chemistry; robotics; computer science; geochemistry; petrology; geodesy; mineralogy; geomorphology; geophysics; glaciology; hydrology; meteorology; planetary engineering; space exploration; space physics; soil science; volcanology.

Summary

Areology, from the words areo (Ares, the Greek god of war) and logy (theory), is the interdisciplinary study of Mars. Most of the earth science disciplines can be applied to areology. As an interdisciplinary endeavor, areology also includes the study of the technologies for Mars exploration, both by robotic and manned craft, and the history of human speculation concerning the prospects for life on Mars, including the scientific principles, expectations, and designs for human colonization, and the engineering of the Martian planetary surface to support human life.

Key Terms and Concepts

Absolute Age: Age of a geological unit measured in years.

Bombardment: Repeated collision of a planet with asteroids, usually over geologic time scales.

Chaotic Terrain: Low region within heavily cratered uplands that appears to consist of irregular, blocky, fractured landscape.

Chasma: Canyonlike feature on Mars, from the Latin for “large canyon or gorge”; the plural is chasmata.

Crustal Dichotomy: Pronounced hemispheric contrast in physical characteristics of a planet’s crust.

Ejecta: Material blasted loose during the formation of an impact crater and deposited around that crater.

Flyby: Mission procedure in which a spacecraft on its way to another destination examines a planet as it flies past that planet.

Gravity Map: A map that shows variations in gravitational attraction across a planetary surface that results from variations found in the internal density of the planet.

Mascon: Acronym for “mass concentration,” which describes a zone of anomalously high density within Mars.

Mons: Term used in names of mountainous features on Mars, from the Latin for “mountain”; the plural is montes.

Planitia: Term used to indicate Martian regions composed of plains, from the Latin for “plains”; the plural is planitiae.

Province: Region of similar terrain or a grouping of geological units with similar or related origins.

Relative Age: Age of a feature or geological unit in relation to other features or geological units.

Rover: Self-propelled, robotically operated vehicle used for exploring the surface of a body distant in space.

Terraforming: Transformation of an alien landscape into one more suitable for human beings.

Vallis: Used in naming valleylike features on the surface of Mars, from the Latin for “valley”; the plural is valles.

Definition and Basic Principles

Areology is sometimes narrowly defined as the study of the geology of Mars, but it more properly involves not only most of the other earth sciences (from meteorology to hydrology to mineralogy) but also space physics, cosmochemistry, and astrobiology. Given that it deals with largely speculative prospects for life on Mars—both indigenous and imported, in the past, present, or future—areology must also take into account both the history of science and the literature of science fiction.

Although the term “areology” was in fact popularized by science fiction author Kim Stanley Robinson in his Mars trilogy (Red Mars, Green Mars, Blue Mars), the debate in the scientific community has largely swung between the poles of “wet Mars” (Mars once had water) and “white Mars” (Mars never had water). American astronomer Percival Lowell, who claimed to see through his telescope visions of supposedly water-filled canals on Mars, established one pole of the debate: Mars was a dynamic planet warm and wet enough to support life at the present time.

From its zenith in Lowell’s work of the 1890’s, this vision of Mars declined to its nadir after the Mariner 4 flyby in 1965. Mariner 4 showed a cratered, dusty ball clad in only the most diaphanous of atmospheres—one whose white polar regions were declared to be most likely covered in dry ice (carbon dioxide rather than water). As the data from the Viking landers of the 1970’s proved inconclusive and controversial, the vision of dry, white Mars dominated discussion of the planet for decades.

After the failures of several probes, the successes of a growing armada of orbiters, landers, and rovers began to suggest in the 1990’s and 2000’s that, cold as it might be, Mars was not as dry and white as many in the planetology community had long contended. The notion that water ice was an important component on the Martian surface made a comeback, along with physical and chemical evidence of a potentially watery past.

The successes and failures of these unmanned spacecraft, along with the discoveries made possible by their successes, have set the parameters for the continuing discussion of the efficacy, expense, and likelihood of manned missions to Mars and eventual human colonization of the planet.

Background and History

Scientific interest in Mars goes back to the seventeenth century and the work of Galileo Galilei, Johannes Kepler, and Giovanni Domenico Cassini—the last of whom, in 1666, observed the Martian polar caps and calculated the length of the Martian day. The apparent Earth-like nature of Mars led French author Bernard le Bouvier de Fontenelle in 1688 and British astronomer William Herschel in 1784 to speculate on the nature of life on Mars.

Despite this, in the scientific community before the end of the nineteenth century Mars was generally not seen as the best candidate for a second life-supporting world in the solar system. Venus—significantly closer to Earth in terms of size, mass, gravity, distance from the Sun, and actual travel time—at first seemed the more likely choice, and was still argued to be such until the advent of radar and radio telescopy, which pierced the thick Venusian atmosphere. Probes then confirmed the planet’s merciless heat.

In literary history, too, the case was similar. Lucian of Samosata wrote of a trip to the Moon in his True History as early as the second century, and in the eighteenth century both Jonathan Swift (in Gulliver’s Travels) and Voltaire (in Micromégas) hypothesized the existence of two as-yet-undiscovered Martian moons. It was not until 1877, after Italian astronomer Giovanni Schiaparelli claimed to see on Mars a network of straight lines he called canali (canals), that writers began to examine Mars as the solar system’s other main abode of life. This shift began with Percy Greg’s Across the Zodiac in 1880 and continued most prominently with H. G. Wells’s War of the Worlds in 1898.

Since Wells, the scientific understanding of Mars has been reflected in—and shaped by—the writings of Aleksandr Bogdanov, Edgar Rice Burroughs, J. H. Rosny, Stanley G. Weinbaum, Ray Bradbury, Leigh Brackett, Robert Heinlein, Isaac Asimov, Philip K. Dick, Frederik Pohl, Kim Stanley Robinson, and many more. Nowhere is the relationship between scientific speculation and speculative fiction clearer than the future Mars projects and programs put forward by space scientists from Wernher von Braun to Robert Zubrin.

How It Works

Telescopy. Although areology is a relatively new term, the roots of a general discipline of Mars studies stretch back nearly four centuries. For the first three and a half centuries, however, these studies were exclusively telescopic. Mars was an object viewed through an eyepiece from Earth. The power of telescopes and the levels of resolution they offered grew steadily over time, and telescopic studies remain very important in areological research, but recognition of the inherent limitations of such studies led the push to move scientific instrumentation closer to Mars via flyby, then linger in orbit to gather more detailed data. Eventually this led to landing scientific payloads on the planet’s surface, then to making those payloads capable of self-propulsion across that surface.

Flyby. Mars 1, also known as Sputnik 23, was launched on November 1, 1962, and was intended to fly past Mars at a distance of about 11,000 kilometers or 7,000 miles. It was the first Soviet Mars probe and carried a package of scientific instrumentation that included television photographic equipment, a magnetometer probe, a spectral reflectometer, a spectrograph, a micrometeoroid impact instrument, and radiation sensors. Data from this instrumentation package were to be broadcast back to Earth via radio and television transmitters. Although Mars 1 lost contact with Earth before accomplishing its flyby, the configuration of its scientific instrumentation package (for collecting data) and transmission capabilities (for returning that collected data to Earth) became the standard for all Mars flyby missions.

The American craft Mariner 4, launched on November 28, 1964, completed the first successful flyby of Mars. Mariner 4’s television pictures of the Martian surface were the first images of another planet sent back from deep space and changed the way the scientific community viewed the possibility of life on Mars. Mariner 6 and Mariner 7, in 1969, were similarly successful flyby missions, making closer approaches and providing more photographic and other data to that already compiled by Mariner 4.

Orbiter. In 1971, Mariner 9 was launched and, once inserted into orbit around Mars, became the first spacecraft to orbit another planet. It was followed soon after by two successful Russian orbiters, Mars 2 and Mars 3.

In orbiting the planet, Mariner 9 photographed 100 percent of the Martian surface and was able to wait out a prolonged dust storm that obscured much of the planet’s surface—something a flyby mission could not have done. Mariner 9’s successful data collection laid the groundwork not only for the later Viking orbiter/lander missions but also for successful later-generation orbiters with more advanced instrument packages, including the Mars Global Surveyor in 1996, and Mars Odyssey, Mars Express, and Mars Reconnaissance Orbiter during the first decade of the twenty-first century.

Lander. The Soviet Mars 3, whose orbiter was successful, also had a partially successful lander component in that its descent module, which contained both a lander and a rover, was able to utilize aerodynamic braking, parachutes, and retro-rockets to make a soft landing. Unfortunately, twenty seconds after touching down the lander stopped transmitting, and it was unable to deploy its rover component.

Considerably more successful were the American Viking 1 and Viking 2 craft, whose orbiters achieved orbit and whose landers, again through a combination of aerodynamic braking, parachutes, and retro-rockets, landed softly and stayed in operation for years, completing scientific objectives that included not only photographic imaging at the planet’s surface but also soil analysis and biological-assay experiments for evidence of organic compounds and, potentially, the presence of life.

Later successful U.S. landers included the Mars Pathfinder lander/rover mission (which utilized air bags rather than retro-rockets during the last phase of its landing) and the Phoenix, which studied the geologic history of water on Mars, its involvement in Martian climate change, and the planet’s past or future habitability.

Rover. Although Russian Mars 2 and Mars 3 descent modules brought rovers with them as early as 1971, no rover was successfully deployed on Mars until the U.S. Pathfinder mission of 1997 deployed its Sojourner rover. Able to travel about a half kilometer, or one-third of a mile from the lander, the Sojourner rover returned 550 photographs to Earth and the data from chemical analyses of sixteen locations on the Martian surface.

Mars Exploration Rovers (MER) Spirit and Opportunity landed on opposite sides of Mars in 2004. Both vehicles were intended to engage in geologic, hydrologic, and biologic assessment activities: to examine rocks and soils for evidence of past water activity, as well as assess whether the environments that prevailed when water was present were conducive to life.

The Spirit and Opportunity rovers have been tremendously successful, their missions lasting more than twenty times the planned duration. Opportunity is still operational and holds the record for longest Mars surface mission. The two rovers have covered far more terrain and have provided far more data than any previous mission.

Applications and Products

The National Aeronautics and Space Administration (NASA) lists more than 2,000 applications and products on its spin-off database. These spin-offs from space research contribute to national security, the economy, productivity, and lifestyle not only in the United States but also throughout the world. These spin-offs are so numerous and ubiquitous that people are scarcely aware of them and too often take them for granted. Below is a sampling of those specifically related to Mars research, many of which were developed in response to areological studies of Martian surface conditions.

Sensors. NASA research into detecting biological Sensors. NASA research into detecting biological traces on Mars has resulted in biosensor technology monitoring water quality. Sensors incorporating carbon nanotubes tipped with single strands of nucleic acid from waterborne pathogens can detect minute amounts of disease-causing bacteria, viruses, and parasites and be used to alert organizations to potential biological hazards in water used for agriculture, food and beverages, showers, and at beaches and lakes.

NASA’s Jet Propulsion Laboratory (JPL) developed a bacterial spore-detection system for Mars-bound spacecraft that can also recognize anthrax and other harmful, spore-forming bacteria on Earth and alert people of the impending danger.

JPL also developed a laser diode-based gas analyzer as part of the 1999 Mars Polar Lander mission to explore the possibility of life-giving elements on Mars. It has since been used on aircraft and on balloons to study weather and climate, global warming, emissions from aircraft, and numerous other areas where chemical-gas analysis is needed.

Computing and Imaging. NASA Advanced Supercomputing (NAS) division, which includes the Columbia supercomputer, is responsible for a wide range of products, from the development of computational fluid dynamics (CFD) computer codes to novel immersive visualization technologies used to pilot the Spirit and Opportunity rovers. Wide-screen panoramic photography technologies developed for the Mars rovers’ Pancam robotic platform is in production as a GigaPan platform for automating the creation of highly detailed digital panoramas in consumer cameras.

Materials. Multilayer textiles developed for the air bags used in the Mars Pathfinder and Exploration Rovers are being used in Warwick Mills’ puncture- and impact-resistant TurtleSkin product line of metal flex armor (MFA) vests, which are comparable to rigid steel plates but far more comfortable.

The thin, shiny insulation material used extensively in the Mars rover missions—a strong lightweight plastic, vacuum-metallized film that minimizes weight impact on vehicle payload while also protecting spacecraft, equipment, and personnel from the extreme temperature fluctuations of space—is found in applications ranging from reflective thermal blankets to party balloons.

Impact on Industry

The annual budget for the entire American space program is about $19 billion, or 0.8 percent of the $2.4 trillion budget. Collectively, however, secondary applications (spin-offs) represent a substantial return on the national investment in aerospace research: $7 from come back from spin-offs for every $1 spent on research. This surplus is generated by taxes from increased jobs in aerospace as well as all the other fields that produce spin-off goods.

Although it is difficult to sort out the actual worldwide spending on research and development relating specifically to Mars exploration and to separate out space-related research from other aerospace and defense spending, the NASA budget for Mars exploration in the first part of the twenty-first century has generally averaged around $500 million per year. Given multiplier effects and the share of Mars-related research in many aerospace-industrialized nations worldwide, including Japan, France, United Kingdom, Canada, Belgium, Russia, and China, the total value of global Mars-related research and development is estimated at roughly $13 billion.

Government and University Research. In Mars exploration-related research, NASA has a robust international relationship with agencies like the European Space Agency and the Japanese Aerospace Exploration Agency and with governmental and university scientific researchers from the United Kingdom, France, Italy, Australia, Belgium, Canada, Japan, Sweden, and Switzerland.

In Mars exploration-related research within the United States government, NASA maintains close ties with many Defense Department units, including the Naval Research Lab but particularly Defense Advanced Research Projects Agency (DARPA) and the U.S. Army, whose work involving tracked vehicles and robotics have paralleled JPL’s work with rovers.

In Mars exploration-related research within NASA itself, JPL is the most important of NASA’s dozen nationwide centers. JPL, which was established by the California Institute of Technology, has formed strategic relationships with ten schools that have major commitments to space exploration: Arizona State University; Carnegie Mellon University; Dartmouth College; Massachusetts Institute of Technology; Princeton University; Stanford University; University of Arizona; University of California, Los Angeles; University of Michigan; and University of Southern California. Through such relationships, JPL and its university collaborators facilitate joint access to particular capabilities in science, technology, and engineering and encourage better understanding of the state of research in the broader scientific community. Such collaborations also support students in space exploration topics, including graduate research on topics of interest to JPL/NASA, student participation in JPL summer programs, and input regarding courses of strong interest to NASA. Such collaborations also cultivate JPL’s future workforce and ensure a pipeline to meet future technical challenges.

Industry and Business. Mars exploration-related research is most closely connected to aerospace and robotics. A single NASA/JPL program in development as of this writing, Distributed Spacecraft Technology Program for Precision Format Flying, involves companies as varied as Guidance Dynamics Corporation, DI-TEC International, Ball Aerospace, Applied Physics Technologies, Tera Semicon Corporation, and Pacific Wave Industries. The true impact, however, is less direct and found largely through the role secondary applications or spin-offs play in the wide variety of industries that make use of sensing, computing, imaging, and advanced materials.

Careers and Course Work

Courses in astronomy, biology, chemistry, computer science, engineering, geology, and mathematics are foundational for students wishing to pursue careers in areology.

Master’s and doctoral degrees are often the necessary minimum qualification for more advanced academic, governmental, or industrial careers in Mars exploration-related science. More specialized courses may include astrobiology, biochemistry, geophysics, climatology, hydrology, geodesy, and robotics, as well as a number of specializations within engineering, particularly mechanical, electrical, human factors, or systems.

Although areology is geological at its root, it is also the general study of a world other than that known to humans and at this point in its development is strongly interdisciplinary, so background in a diversity of fields, including the history of science and the study of literature concerning Mars, can also prove very helpful.

Social Context and Future Prospects

For areology, the twentieth century was shaped by two important movements. One was the transition from an understanding of Mars based on telescopy to one characterized by spacecraft with scientific instrument payloads flying by, orbiting, landing, and discharging mobile quasi-autonomous vehicles onto the surface to “follow the water” and look for evidence of life. The other was the movement from an understanding of Mars based primarily in fictional speculation to one increasingly based in science.

The question of past or present life on Mars, however, remains in the realm of speculation. The great debates in this century for areology will begin with whether remotely controlled or increasingly autonomous robotic vehicles can conclusively decide the question of past or present life or whether that question can be conclusively decided only through expensive, potentially dangerous (and perhaps infeasible) manned missions to Mars. That in itself, however, presents a problem: If there is no life on Mars, should the planet be preserved in its pristine state? Conversely, if there is life on Mars, should people risk causing the extinction of that life through contamination from Earth—or humanity’s own extinction, through contamination from something on Mars?

These sound more and more like the speculations of science fiction, and matters become only more speculative as people contemplate the efficacy and feasibility of expensive, dangerous, and longer-term effects of colonization and terraforming of Mars by humans.

In trying to find Mars analogues on Earth, scientists are learning more about the limits to life on the world. By setting up microbial observatories in environments that may be in at least one way or another like certain environments on Mars, people have broadened their understanding of the diversity of life on Earth, ultimately serving to make Mars and Earth look more like each other at their extremes than previously assumed.

Further Reading

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