Mission to Mars
IN THE LONG-AGO SUMMER OF 1969, when everyone who wasn't obsessed with Chappaquiddick or Woodstock was glorying in the triumph of the first manned moon landings, it was hard to find anyone who cared a whit about the Mariner 6 and Mariner 7 missions to Mars. Among other duties, the two flybys measured the Red Planet's ionosphere (the shell of charged particles high in the atmosphere). Their observations, and later ones, showed that shortwave radios, which bounce signals off this layer of ions, would work on Mars, and thus that 21st-century colonists could communicate with their base camp while exploring the cratered Martian terrain. No one noticed.
In 1976, when the two Viking landers confirmed that the Martian atmosphere was more chock-full of carbon dioxide than a bottle of seltzer, hardly anyone grasped the implication: that tons and tons of rocket fuel could be synthesized out of Mars's air, making traveling to and from Mars even easier than trips to the moon. In the 1980s, Martian meteorites revealed that the planet's soil contains lots of gypsum. No one pointed out that the find meant that astronauts on Mars could bake the gypsum, add some Martian water and iron-rich dust and thereby manufacture, on Earth's sibling planet, enough Portland cement to build an extraterrestrial Jamestown.
CEMENT PLANT ON MARS. Now there's a headline that should have been bannered, but it wasn't. Since Apollo, NASA had backed off from sending humans into space (for anything other than crewing the space shuttle), and certainly did not wax poetic about ham radio-wielding astronauts bounding across the cratered lowlands of Mars. After the first lunar landings, the public cared as much about moon shots as about the local Greyhound departures. Astronomers happily droned on about the ""Martian magnetosphere'' and other scientifically important but deadly dull finds; if they suspected that a particular discovery might pave the way for earthlings to fly to Mars, they kept mum. That doesn't mean, though, that no one was keeping alive the dream of Mars. The Mars Underground was.
For 15 years this informal network of space scientists and engineers has been quietly tracking discoveries from unmanned missions to Mars. Working for aerospace firms, universities and NASA itself, they'd tell anyone who would listen how earthlings, not robots, could fly to Mars, explore there and, one day, even build colonies there.
Now people are listening. It's too soon to apply for a mortgage on your own little acre in the Valles Marineris. But with the report last month that life may have gained a toehold on Mars 3.5 billion years ago, space scientists suddenly have good reason to look more carefully at those blueprints for getting humans to Mars. If there was once life on Mars, and especially if there is still life on Mars, then the cataclysmic climatic changes that turned the planet into a cold, barren desert forced organisms deep underground. The chances of robots' finding them are about the same as Antonio Banderas's striking out at a singles bar. Enter astronauts. ""Exploring below the Martian surface for water and living microorganisms,'' paleontologist Jack Farmer of NASA's Ames Research Center in California said last week at an ""astrobiology'' conference, ""may provide the most compelling reasons for carrying out human missions to Mars.''
And Robert Zubrin, the de facto chairman of the Mars Underground, can get us there on a consolidator ticket. In 1989, after President George Bush called for a manned mission to Mars, NASA costed it out: $400 billion, 30 years. A lot of money just to watch some spacesuits clomp around a crater field and plant a flag. So in 1990 Zubrin, then an engineer at Martin Marietta Astronautics, and colleague David Baker dreamed up a way to reach the planet on the cheap. The idea, as he puts it in ""The Case for Mars'' (318 pages. Free Press. $25), which will be landing in bookstores next month, is to ""live off the land.'' Off the air, actually. To carry enough propellant to get the Mars crew back to Earth, NASA's ship would have to be huge. And assembled in space. At a multibillion-dollar space station. Zubrin seized on the fact that Mars's atmosphere is 95 percent carbon dioxide, and balanced a few chemical equations. His conclusion: by reacting the carbon dioxide with hydrogen brought from Earth, you could produce enough liquid oxygen and methane fuel to fly back to Earth. You would even have enough to top off the tanks of some rovers and scoot around Mars for 500 days. It would cost $55 billion, according to NASA. But it would cost just $5 billion, according to Zubrin, if carried out not by the government but by private companies, lured by a $20 billion prize established by Congress.
Zubrin's was a mission in search of a reason until last month's hints of life on Mars. Now, at NASA centers from the Jet Propulsion Lab in Pasadena, Calif., to Johnson Space Center in Houston, engineers and scientists are working feverishly to design a veritable flotilla of spacecraft that will map Mars from orbit, set down a rover to explore the terrain and eventually bring back a sample of rock and soil to analyze for signs of past or present life. ""We are committed to the aggressive plan we have put in place for the robotic exploration of Mars,'' President Clinton declared last month. The first few missions (timeline) are in the can, so to speak, and can't be changed to carry instruments better attuned to detecting life past or present. One instrument on Mars Global Surveyor, which is already parked at Cape Canaveral for a Nov. 6 launch, can detect minerals that mark places where water, and hence life, might be ""if they are exposed on the surface,'' says Christopher McKay of Ames. ""I am guessing that they have a 50-50 chance of getting a hit.''
So engineers are frantically trying to stuff future missions--which were designed to concentrate equally on Martian climate, resources and biology--with more instruments able to search for life or its remains. Wes Huntress, NASA's chief scientist, calls it ""a "let's change strategy' approach.'' The first target is the ""sample-return mission.'' It was originally scheduled for 2005, but now the NASA brass is pressuring engineers to get it off by 2003. JPL, headquarters for robotic planetary missions, is designing a sample return, which would snag a rock or pile of dirt likely to harbor microorganisms or fossils and get it back to Earth. But Johnson Space Center, mission control for manned flights, is neverthe- less designing a rival approach. The labs aren't yet e-mailing computer viruses to sabotage the other's work, but the competition is heating up.
JPL's first entry might be called The Right Stuff: it's modeled on the Apollo moon landings. A mother ship would orbit Mars. Then it would jettison a lander--like the moon landers--which would touch down on Mars, collect its sample, then rendezvous with the orbiter for the return home by 2006. Alternatively, in the Brute Force approach, a rocket would land on Mars, disgorge a rover that would pick up some souvenirs and return to the main ship, which would then blast off for Earth. A brainstorming session at JPL earlier this month, attended by NEWSWEEK, showed the drawbacks of both ideas. Because the missions would carry enough fuel not only to get to Mars but also to return, they are superheavyweights. Adding so much as a power supply for a radio beacon threatens to make them so ponderous and expensive that they'd be way beyond NASA's downsized budget. To make weight, the engineers were reluctantly throwing out instruments and other cargo right and left. And because unheated rocket fuel would freeze on Mars, the lander could stay there for only four days in one scenario. That's not much time for the slow- moving rover to find some biologically interesting dirt and get it to the ship. But the worst part is that the weight con- straint lets the mission bring back only 10 ounces of Mars.
The Johnson team has embraced the ""live off the land'' philosophy. ""I want to land on Mars with empty fuel tanks,'' says David Kaplan, Johnson's lead scientist for the sample return, ""and run a self-service gas station there [carried up intact and then rolled out of the lander]. Then we wouldn't have to spend every penny of our technology money to make things lighter and smaller.'' The launch weight of his craft would be 38 percent lighter than the JPL plans. Every kilogram shaved off the spacecraft is $150,000 saved. It could stay on the surface as long as required to get the goods, since all the weight saved by not carrying return-trip fuel leaves room for a solar-powered heater that would keep the fuel warm and ready to burn. Making fuel would also let the JSC mission bring back several pounds, not 10 ounces, of Mars. The NASA brass has to decide five years before launch which design gets the green light.
Where should the sample-return rover look for extinct or extant life? Martians won't be waiting on the tarmac for interplanetary arrivals, so scientists are poring over new research on homegrown life for clues on where to dig. Clue number one: life existed on Earth at least 3.87 billion years ago, as researchers from the Scripps Institution of Oceanography presented at last week's astrobiology meeting. That era, as it happens, is exactly when Earth and Mars were virtual twins: warm, riddled with volcanoes and active thermal vents and, most important, wet. Looking for life means looking for water. On Mars, that means desiccated lake and river beds, and ""outflow channels,'' where torrents carrying 50,000 times more water than the Mississippi River once thundered. Clue two: life on Earth can make a go of it in the most unforgiving places--in cracks in rocks deep under the Columbia River basin, inside solid volcanic rock and in searing-hot thermal vents bubbling up from the ocean floor. Many of these simple organisms draw energy from chemicals such as methane, sulfur and hydrogen. Not to put too fine a point on it, they eat rocks. ""Even in bizarre environments,'' says NASA's Huntress, ""wherever there is liquid and energy, there is life.''
Places that have, or had, water and energy, then, are prime biological prospecting sites (map). They include ancient hydrothermal systems, like the vents and fumaroles and hot springs at Yellowstone National Park, and possibly permafrost in the Martian tundra. ""If life on Mars did originate in hydrothermal vents [as it is thought to have done on Earth],'' says planetary scientist John Kerridge of the University of California, San Diego, ""there's a reasonably high probability that organisms could have been fossilized.'' The silicas and carbonates spewing out of the vents can encase a microorganism like a bug in amber. Places without water or energy--like the places where the Viking landers parked in 1976 and failed to find signs of life--are not biologically promising real estate. NASA doesn't want to be looking for life in all the wrong places a second time. As Huntress says, ""we want to bring back not just any interesting sample, but one with evidence of early life.''
Or, even better, survivors. If there was once life on Mars, where would it have retreated, 3.5 billion years ago, when the warm, wet world changed, for reasons scientists cannot explain, into a freeze-dried desert and much of the atmosphere escaped into space? Someplace with water. Astrobiologists are eager to get modern-day divining rods to Mars: microwaves and neutron- and gamma-ray spectroscopy can detect aquifers and ground water. They also want instruments that can locate geothermal sources, which could maintain liquid water nearer the frigid Martian surface. They want to excavate ground ice where mineral-eating organisms living below the surface may have been washed up and cryopreserved. Dry lake beds offer the most tantalizing possibility of all. When lakes evaporate, salts come out of solution and form crystals. Any salt-resistant bacteria in the lake could have been trapped inside ""brine inclusions''--little pockets of salt water in the crystals. These ""evaporites,'' which Mars Surveyor has a chance of detecting from orbit, may be where surviving life on Mars holed up. They're not going to be fish, or anything bigger than a few cells at most. But on Earth, viable microorganisms isolated from salt crystals have been tentatively dated at 200 million years old.
Some scientists, not to mention headline writers, think we already have evidence of Martian life, courtesy of the Antarctic meteorite that used to be a chunk of Martian crust. But the chemicals in the rock are ambiguous: lots of reactions produce thee polyaromatic hydrocarbons (PAHs) taken to be evidence of a living thing's decomposition. The ""fossils'' are even more problematic. The human eye is notorious for discerning forms and shapes in random patterns, like the supposed ""face'' on Mars itself. Only finding a fossilized cell membrane might clinch the case. However life got started--still a mystery--it needed a membrane to hold, in one little bag, the genetic coding and proteins that constitute life. Single-celled creatures eventually banded together about 2 billion years ago on Earth. Then some of the cells mutated, becoming different from the others, 550 million years ago. The giant step toward the evolution of multicellular creatures had been taken. But unless life on Mars ran on chemistry completely different from that of terrestrial creatures, it would have had trouble getting past step one. By 2 billion years ago, some of the life-giving gases in Mars's atmosphere had collapsed like a soufflE. Others, notably oxygen and nitrogen, escaped into space.
If the budget hawks in Washington suspect that scientists are using the hints of life on Mars as an excuse for missions beyond a little biological prospecting, they're right. Lofting manned missions to Mars ""at the same rate we currently launch the space shuttle,'' says Bob Zubrin, ""the United States today could populate Mars at a rate comparable to that at which the British colonized North America in the 1600s.'' Getting there, in other words, is easy. Living there--well, Zubrin thinks that's not exactly rocket science, either. The key, again, is using the resources on Mars rather than hauling them over from Earth. The Pilgrims, after all, did not bring their own wood. The new Martians could dispatch roving microwave units to zap the Martian permafrost and extract water. Mixing water with Mars's finely ground, claylike dust, putting it in a mold and drying it would produce pretty good bricks. Mixing the red dust with water would produce mortar. The calcium and sulfur in Martian soil are in the form of gypsum, the stuff of plaster. And in case any of this becomes a reality, he has also worked out the chemical equations for producing ethylene gas (the basis for petrochemicals and plastics) out of Mars's air, and metals and glass out of Mars's soil.
Eventually, in the dreams of the Mars Underground, a base becomes a town. The town becomes a colony. One day the colonists ""terraform'' Mars--make it Earth-like. Zubrin thinks the colony, far from being a budget buster, could become self-supporting. It could export, to Earth, patents and inventions produced by its technologically adept settlers. But is that enough reason for earthlings to take the first tentative steps toward the stars? Throughout the centuries, from the time that the first early humans ventured out of Africa to the great voyages of the Age of Discovery, humankind has found more than ample reasons to venture into unknown worlds. The impulse to explore ""is always out there,'' says historian Robin Winks of Yale University. ""It is part of the human condition.''
The last time such rhetoric soared, President Kennedy was challenging the nation to marshal its know-how, its energy and its spirit to put men on the moon. But 1996 is not 1962. President Clinton's 1997 budget will cut NASA's space-science funding from $2 billion to $1.8 billion; cuts would continue for at least five more years. NASA has been careful not to use the life-on-Mars claim to ask for more money. But the sample-return mission is already budgeted at $500 million; moving it up, or loading more, life-seeking instruments on flights scheduled for 2001 and beyond will clearly cost more. Although both Vice President Al Gore and House Speaker Newt Gingrich told NASA last month that they would try to find more millions to support missions to Mars, an equally likely possibility is that the space agency will have to cannibalize the budgets of other missions, from asteroid flights to research on the Earth's climate, to bankroll Mars. In centuries past, civilizations have sallied forth into the unknown for reasons of ideology, politics, commerce and even romance. Now that engineers have a way to get to Mars and scientists have a goal once we arrive, all that's missing is the will.