‘Heroes or Zeros’: High Stakes for Mars Team
Since human eyes first turned skyward, Mars has been a distant red object of desire that, more than any other outworld, exerts a tidal pull on the imagination.
Long the focus of hopes for alien life in the universe, it has been haunted for generations by speculative and scientific phantoms--canals, vegetation, ice-eating crystophages, even faces and pyramids.
More recently, the voyages of the Mariner, Viking, Pathfinder and Global Surveyor spacecraft galvanized global attention and revealed a planet that may once have harbored primordial microbes but is now an eerie place of dunes, dust devils, dry ice, dead volcanoes and subzero winds. Blue clouds adorn its salmon pink sky and strange magnetic stripes its soil.
Under such scrutiny, the prospect of life on Mars has receded ever further into the planet’s past, and the search for clues focuses ever deeper beneath the planet’s sterile surface.
This week, that pursuit will bring 100 scientists from five countries to UCLA and the Jet Propulsion Laboratory with their hopes pinned on a spindly robot called the Mars Polar Lander.
The stakes are heightened even more than usual by the loss, caused in September by a navigation error, of the $125-million Mars Climate Orbiter and by problems uncovered in the Polar Lander by the investigation into that failure.
As the craft bears in on Mars at 10,870 miles per hour, JPL engineers are working to correct those technical problems, which could jeopardize its mission. JPL managers added 37 senior engineers and navigators to the task and spent an extra $2 million in additional readiness reviews and systems tests.
If all goes well, the $165-million lander is expected to touch down near the Martian south pole on Friday after a journey of 470 million miles. For 90 days, it will seek evidence of water and other data to help scientists understand the ancient climate on Mars and, by inference, its suitability--once upon a time--for life.
The Polar Lander will be the first craft to explore the south polar icecap and the first to carry a microphone to relay the sounds of another world. But first it has to negotiate a complex landing maneuver on the heels of the Climate Orbiter loss.
“We are always really, really nervous at this point in a mission, but the nervousness has increased a lot more,” said Louis Friedman, executive director of the Planetary Society, which is sponsoring the microphone experiment. “So much is at stake for the Mars program, for NASA and for JPL.”
Indeed, as the Mars landing nears, a number of NASA’s other missions are hobbled by technical problems.
Its $152-million Deep Space 1 probe, cruising 150 million miles from Earth, has been on standby since Nov. 11 because of a problem with its on-board tracking system. The Hubble Space Telescope has closed its eye on the universe, shut down by a frozen gyroscope. The agency’s aging space shuttle fleet only now is resuming normal operations after being grounded since July with wiring problems. NASA hopes to dispatch a shuttle crew Dec. 9 to repair the Hubble in orbit.
Between operational readiness tests, seven planetary scientists, all involved in experiments aboard the Polar Lander, recently gathered for dinner in a Westwood bistro. More than one has already lost a scientific instrument--and a decade or more of a career--on a planetary explorer that vanished en route to the fourth planet.
As they thumbed menus, they toted up the record. Of 32 missions launched to Mars by three countries in 39 years, 21 have crashed, misfired, malfunctioned or disappeared.
But those that completed their solitary voyages offered dazzling new vistas of an alien worldscape. By itself, the $270-million Pathfinder mission in 1997 returned 17,050 photographs of Mars, and 8.5 million measurements of its thin, carbon dioxide-rich atmosphere.
“To Mars!” toasted William Boynton from the University of Arizona.
The others raised glasses of cabernet or mineral water in salute.
JPL meteorologist David Crisp, a second experienced planetary voyager, wryly completed the toast: “Heroes or zeros.”
The others clinked their glasses together.
“To Mars; heroes or zeros.”
Planet May Hold Keys to Earth’s Past
At almost every turn, Mars confounds expectations.
“It always surprises us; that is what makes it so interesting,” said Laurie Leshon, a geochemist at Arizona State University who is a member of the Polar Lander science team.
Scientists who saw the first images of the planet’s surface, transmitted from orbit by the $83-million Mariner 4 in 1964, were shocked to see a heavily cratered world that resembled the moon more than the verdant, Earth-like planet they had expected.
Only later did they realize the blasted terrain represented just a fraction of the planet’s surface.
“Our understanding of Mars then was so rudimentary that we didn’t know what its atmosphere was, whether seasonal changes in light were caused by vegetation or what,” recalled Daniel McCleese, chief scientist of JPL’s Mars exploration program. “In that period, extant life on Mars was a possibility.”
Twelve years later, researchers analyzing data returned by the $2-billion Viking missions--the first U.S. Mars landings--were equally dismayed when sensors designed to detect chemical traces of life not only failed to find anything alive but could not detect any organic molecules at all on the planet’s surface.
It was a rude awakening.
Not so long before, the idea of an advanced, canal-building civilization on Mars had been so widely accepted that a fictional 1938 radio announcement about marauding Martians landing in Grover’s Mill, N.J., triggered a national panic.
No Viking mission scientists ever expected to see the Martian swashbucklers of Edgar Rice Burroughs’ science fiction tales. But prior to that Viking landing, experts from astronomer Carl Sagan to Nobel laureate Joshua Lederberg were certain that there would be primitive flora and fauna of some sort.
The disconcerting discovery that the Martian surface was as lifeless as the inside of a hospital sterilizer effectively ended Mars exploration for almost 20 years.
It took a better understanding of life’s tenacity on Earth to rejuvenate the search for life on Mars.
The example of terrestrial microbes that thrive in boiling springs, in sulfur-rich undersea vents, in radioactive waste or miles underground lent credence to the idea that what could not survive on the Martian surface might live deep in its interior.
Sophisticated genetic analysis of terrestrial bacteria also revealed that the biochemistry of Earth’s first organisms may have originated under extreme conditions lethal to life today, conditions that could well have been present on ancient Mars.
When new geologic evidence turned up that life arose on Earth at least 3.9 billion years ago, it helped bolster the idea that Martian life could have developed very early in the planet’s history--at a time when it had a denser atmosphere, active volcanoes and so much liquid water that the surface today still bears the imprint of catastrophic floods.
“Mars became a key to the past of our own world,” McCleese said. “Perhaps Mars would provide clues erased on Earth.”
To be sure, the discovery in 1996 that a 4-billion-year-old Martian meteorite might bear the traces of primordial micro-fossils fit this theory nicely. But after two years of sustained study, many scientists are convinced the rock--blasted from the Martian surface by an asteroid or comet and later making its way to Earth--only shows evidence of wishful thinking.
In March, David S. McKay at NASA’s Johnson Space Center announced that two more Martian meteorites appear to contain possible tiny traces of fossilized bacteria. The apparent micro-fossils were detected in samples from a 1.9-billion-year-old meteorite found in 1911 near Nakha, Egypt, and from a 165-million-year-old meteorite that fell near Shergotty, India, in 1865.
But many researchers also find that claim far from convincing.
Meanwhile, new data from the $300-million Mars Global Surveyor, which has been orbiting the Red Planet since 1997, continues to jolt cherished illusions.
Under the gaze of the Surveyor’s sharper optics last year, what some people insisted was a mile-wide artificial face and a city of pyramids on the Martian plain of Cydonia dissolved into naturally eroded cliffs and wind-swept dunes.
In the same way, outlines of what seemed to be ocean shores now also have disappeared. After scientists earlier this month received new, higher-resolution Mars images, they concluded there is no evidence of shorelines that would have surrounded oceans that may once have existed on Mars.
But even as it dashes conventional ideas of the planet’s character, the Global Surveyor and the other voyagers in this new wave of Mars exploration are revealing a world far more dynamic and weird than anyone imagined.
“Mars is its own place,” said Michael Malin at Malin Space Science Systems in San Diego, who is in charge of the Surveyor’s imaging system. “And we have yet to come to grips with what that place really is.”
A Huge Variety of Land Forms
Mars is home to the highest, lowest and smoothest land forms in the solar system, with a volcano as big as Arizona, a crater deep enough to swallow Mt. Everest, and a valley as long as the United States is wide.
So much lava spewed from one ancient volcano that it could have buried the continental United States four miles deep in magma. High-resolution images of the Valles Marineris reveal what appear to be bedded rocks 100 layers deep that could be ancient lava flows or sedimentary deposits.
Like a pear, the planet slopes from its south pole to its north pole, its surface pocked by splash craters that may have formed when molten lava came in contact with a water-rich surface, recent images suggest.
A new, three-dimensional topographical map of the planet, based on millions of elevation measurements gathered by the Surveyor, shows that the northern hemisphere is so flat that it suggests the smoothing effects of standing water.
Indeed, a huge depression in the northern hemisphere that dips 6 miles below the average elevation of Mars resembles an ancient ocean basin.
By contrast, the southern hemisphere is heavily cratered and is, on average, about three miles higher in elevation than the northern half of the planet.
Pathfinder data suggest the planet was awash in water 3 billion to 4.5 billion years ago. The primordial flood plain around the Pathfinder landing site, however, seems to have been bone dry for at least 2 billion years.
In February, the Surveyor transmitted a new image of a deeply carved, sinuous channel in Nanedi Vallis that several scientists consider the best evidence yet that water--a prerequisite for life--existed on the planet’s surface for prolonged periods.
No one knows where the water went.
While the scientists of the Mariner era worried that Mars was a dead orb, more detailed recent observations are revealing that the planet is dynamic, constantly reshaped by the forces of nature.
“Mars is a cold, dry desert, but our camera has shown it is far from being a stagnant place,” Malin said. “We see dust devils, dust storms, snowstorms.”
It can be a scene of unearthly beauty.
From orbit, a wide-angle camera in September caught an image of the shadow of the Martian moon, Phobos, as it chased across the surface of the volcano Olympus Mons during a solar eclipse caused by the passage of that tiny moon between Mars and the sun.
In May, swirling columns of dust up to five miles high could be seen winding across the northern plain of Amazonis Planitia, sculpting new forms in the rust-colored sand.
No part of the planet, however, is more provocative, or more unexplored, than the southern landscape where the Polar Lander will come to rest Friday.
The southern icecap is almost wholly frozen carbon dioxide. The region contains a layer cake of dust deposits with thick tongues of dry ice boiling away into vapor as spring comes to the Red Planet this month.
“Any time you see a cut [in the surface], a gulley or a crater wall that dissects the soil, you can count the layers and find they go mile after mile like flat sheets,” said Peter Smith, the University of Arizona scientist in charge of the spacecraft’s cameras. “This [mission] will be totally different from Pathfinder and the two Vikings, which were on a rock-strewn plain. There is a tremendous variety of land forms down there. We see layers, mounds and what look like spider webs, polygons, ice features, and it changes every two to five miles.”
Researchers want to dig beneath the surface in the hope they will find sheets of frozen water and the chemical traces of a changing climate. If they discover water underground, it will bolster theories that the planet could still harbor hidden reservoirs.
Aboard the lander is a $22-million UCLA instrument package called the Mars Volatiles and Climate Surveyor (MVACS), which, in addition to cameras, contains a robot arm, a package of weather sensors and a gas analyzer to investigate the soil samples the arm is able to retrieve.
Scientific Team Has New Home Base
The lander’s robot arm is about as strong as a human arm, so it can break through any wind-packed crust it may encounter. It is designed to dig a meter deep into the polar dirt. If the soil layers are thin enough, such a ditch could encompass 100,000 years of history.
“We believe that this layered terrain is a record of climate changes on Mars,” said Richard Zurek, the lander project scientist. “And in a sense, digging into its surface will be like reading tree rings or layers in an ice core.”
For scientists seeking to understand Mars, there will be hope in each scoopful of dirt.
In a sense, David Paige has been on Martian time for much of his life.
But now the UCLA planetary scientist is resetting his personal clock in earnest to the longer day and different seasonal rhythms of the fourth planet.
As the principal investigator in charge of the lander’s MVACS experiments, Paige will be spending the next three months working on a Martian day shift that will run from about 4 p.m. to 2 a.m.
Winter may be settling in on Los Angeles, but the spring thaw is beginning on Mars.
“Everything is phased to the Mars clock,” he said.
As Paige dodged between the computer terminals and ergonomic chairs in the newly furnished UCLA Mars operations center, his casual air belied the expectation in the room.
If the spacecraft will be exploring new Martian terrain, the science team itself will also be entering its own new territory.
It will be the first time the science operations for an interplanetary mission of this scale will be housed at a university, not at JPL. It is another example of how interplanetary missions are becoming more decentralized in the effort to lower the cost of exploring space.
All told, 132 scientists are involved in the lander experiments, and during the mission at least 75 of them are expected to be working in the UCLA center.
One end of the L-shaped center is dominated by a full-scale operating mock-up of the 1,270-pound lander in a 300-square-foot sandbox. Technicians will use it to rehearse complex maneuvers before committing the real vehicle on Mars to action. A color mural of Antarctica’s dry valleys--the nearest thing on Earth to a Martian landscape--covers the walls behind the lander model.
The other end of the black room is occupied by a conference table long enough to seat 25 scientists and a wall of video projection screens that, come landing day, will allow them a picture window overlooking the Martian south pole.
“This is a scientific expedition very much in the spirit of exploration at the turn of the century, when people went to expand the limit of our knowledge,” Paige said. “This is the first real, deliberate attempt to exploit the diversity of Mars. Each region has its own story to tell about the planet’s history.
“The south pole of Mars is as different a place as you can imagine.”
Dining recently in a Chinese restaurant near UCLA after a four-day operational readiness review, Paige polished off a plate of dim sum with a fortune cookie.
His tiny strip of paper read:
“There will always be delightful mysteries in your life.”
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The Mars Millenium: A Timeline
3000-400 BC
Egyptian astronomers chart Mars, which they called Har Decher--the Red One.
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1609
Galileo Galilei first views Mars with a primitive telescope.
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1719
Mars orbits so close to Earth that its appearance in the sky causes panic. Not until 2003 will Mars again pass so near Earth.
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1784
British astronomer Sir William Herschel writes that the inhabitants of Mars “probably enjoy a situation similar to our own.”
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1895
Noted U.S. astronomer Percival Lowell publishes “Mars.” He writes: “We have been led to regard it probable that upon the surface of Mars we see the effects of local intelligence.”
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1912
Edgar Rice Burroughs writes “Under the Moons of Mars,” the first of many of his science fiction thrillers about the Red Planet.
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1938
Orson Welles and the Mercury Theater of the Air broadcast H.G. Wells’ “War of the Worlds.” It triggers a national panic.
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1950
“The Martian Chronicles,” by Ray Bradbury, is published.
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1956
“The Exploration of Mars,” by Willy Ley and Wernher von Braun, is published.
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1960
First spacecraft to Mars is launched by the Soviet Union. It burns up in Earth’s atmosphere. The next four Soviet Mars missions also fail.
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1964
U.S. launches the first successful mission to the Red Planet, Mariner 4, on Nov. 28.
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1971
Soviet Union lands first craft on Martian surface on Dec. 2. Its instruments fail 20 seconds after it touches down.
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1976
The U.S. Viking 1 Lander touches down at Chryse Planitia on Mars on July 20.
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The Viking 2 Lander touches down at Utopia Planitia on Sept. 3.
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1988
Two Soviet Mars missions fail.
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1993
U.S. Mars Observer disappears near Mars on Aug. 21.
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1996
Scientists announce in August that a Martian meteorite contains evidence of fossilized bacteria.
Russian Mars 96 mission fails Nov. 17.
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1997
U.S. Mars Pathfinder lands on Mars on July 4.
U.S. Mars Global Surveyor reaches Mars on Sept. 12.
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1998
Japan’s first Mars probe, Nozomi, is launched July 3. It is expected to reach Mars in December 2003.
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1999
Mars Climate Orbiter vanishes Sept. 23 as it orbits Mars.
Mars Polar Lander scheduled to touch down on Mars on Dec. 3.
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Return to the Red Planet
For centuries Mars has inspired ideas of extraterrestrial life and spurred 31 missions in search of evidence. The discoveries have changed views of the Red Planet, now known for its arid atmosphere, dunes and craters. The latest mission is by the Mars Polar Lander, which is expected to touch down at midday Friday, near the Martian south pole, to search for underground frozen water and study the atmosphere.
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Source: NASA,Caltech,JPL
Researched by LYNN MEERSMAN and LESLIE CARLSON / Los Angeles Times
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