The Rock From Mars (43 page)

But many people
• Wilhelms,
To a Rocky Moon,
pp. 232–43; Murray and Cox,
Apollo,
pp. 447–49; Chaikin,
Man on the Moon,
pp. 335–36, 349, 505–06.

Their haul would
• Wilhelms,
To a Rocky Moon,
pp. 329, 333; Chaikin,
Man on the Moon,
pp. 521–22. Meteorite and lunar specialists Larry Nyquist and Wendell Mendell, at NASA’s Johnson Space Center, told the author that, while the oldest lunar specimen reported in the published literature was found to be 4.57 billion years old, it was “an outlier.” The most ancient lunar rocks tend to be in the age range of 4.42 to 4.43 billion, they said. See Marc Norman, “The Oldest Moon Rocks,”
Planetary Science Research Discoveries
, April 21, 2004, at http://www.psrd.hawaii.edu/April04/lunarAnorthosites.htm. The article discusses Norman’s research (with Nyquist and Lars Borg), and Mendell noted that, though Norman “never cites an age older than about 4.40 billion, deep in the article he mentions ‘an unexpectedly large range of ages (4.29–4.54 billion years)’ from other measurements.” The article suggests that “the unexpected large range of ages’ on these rocks may be due to disturbances in the isotopic compositions due to the effect of impacts on the rocks over time,” Mendell said. “As you can see, this is fuzzy business.”

Toward the end
• Wilhelms,
To a Rocky Moon,
p. 330; Chaikin,
Man on the Moon,
pp. 527–53.

A nearby McDonald’s
• See Stephen Harrigan, “Heaven and Earth,”
Texas Monthly
(Apr. 2003): p. 128, for the height and makeup of the faux astronaut.

He had become
• Author interviews with geologist Abhijit Basu (now a professor of geological sciences at Indiana University, in Bloomington), Chris Romanek, and others familiar with McKay’s microscope work. Basu recalled the story of McKay fetching the engineering drawings.

McKay’s natural bent
• Author interview with Basu.

He had accepted the
• Mimi Swartz, “It Came from Outer Space,”
Texas Monthly
(Nov. 1996): p. 122.

By now, McKay had
• McKay shared not only his expertise but his samples with fledgling scientists who came to work in his lab. Over the years he nurtured many, including Abhijit Basu from India. In 1975, just a few years after the lunar samples arrived on Earth, McKay gave Basu some of his—no strings attached, no stipulations about who would get credit for the work—even though McKay knew the younger man would not be coming to the Houston lab as a postdoctoral fellow. (Basu opted for Harvard instead.) Basu said in an interview with the author that he considered this an act of remarkable generosity, given how rare it was for investigators to swap the precious samples so freely.

Wendell Mendell, a
• Author interviews with Mendell.

Civil servants, for instance
• Author interview with Tim McCoy, Smithsonian meteorite curator.

As one occasional participant
• Author interview with Basu.

But McKay preferred
• Author interview with McKay.

As he would remark
• Goldsmith,
Hunt for Life on Mars,
p. 69.

CHAPTER THREE:
odd ducks

In one of these
• This chapter’s account of Mittlefehldt’s key research on the Mars meteorite comes primarily from author interviews with him and an account he wrote in
Planetary Report,
vol. 17, no. 1 (Jan.–Feb. 1997): pp. 8–11.

And in the years
• The author thought the admirable phrase “keys that can unlock the vaults of cosmic memory” (found in her notes) came from Ralph Harvey or the website he operates for the meteorite search program, but he has denied parentage and she has been unable to determine its source.

After Robbie Score’s hunting
• Author interview with Cecilia Satterwhite of NASA contractor Lockheed Martin, a veteran “hands-on” meteorite curator at Johnson Space Center. She breaks space rocks for a living. Regarding the level of cleanliness in the meteorite processing lab, curator Kevin Righter told the author in an e-mail that it was a Class 10,000 facility. In 1997–1998, the air handler system would be replaced and upgraded, he said, “and it has effectively operated as Class 1,000 or better since then (even though the official rating is 10,000).” The class refers to the number of dust particles and other impurities per cubic foot that the air filters admit at or above a certain size. Class 1,000 meets a higher standard than Class 10,000, admitting fewer particles larger than 0.5 microns.

Here, the curators weighed
• Author interviews with Carlton Allen and Satterwhite, of the JSC meteorite facility. See also
Antarctic Meteorite Newsletter
vol. 8, no. 2 (Aug. 1985): p. 5, and Charles Meyer,
Mars Meteorite Compendium
(Washington, D.C.: NASA/JSC, 2001), p. 107; on Web at: http://www-curator.jsc.nasa.gov/curator/antmet/mmc/84001.pdf.

There, the task
• Author interviews with Glenn MacPherson, Chris Romanek, and Tim McCoy. (As of this writing, MacPherson was chair of the department of mineral sciences at the Smithsonian’s National Museum of Natural History.)

His finding appeared
• Interested research labs routinely received these bare-bones descriptions of the season’s new meteorite arrivals by means of the newsletter circulated by the Houston archives and based on the Smithsonian analysis.

But this was in part
• Author interview with MacPherson.

Otherwise, his initial bulk
• The rock was mostly (90 to 95 percent) made of a silicate material (orthopyroxene) similar to the material found in other offspring of Vesta—except it was a bit richer in iron. Mittlefehldt noted that it had been banged up and there were cross-cutting veins of granular material, but there were also still patches of the original igneous rock—the material into which the primordial magma had cooled and solidified. In that sense, it was quite different from most igneous meteorites—those formed from molten rock. Most had been so banged up by impacts on the parent body that there was nothing left but fragments from the original material, a mixture of grain sizes from microns up to perhaps centimeters. (From author interviews and Mittlefehldt’s reports.)

But it took a
• Mittlefehldt and his coworkers would later write a paper about the lessons learned from the misclassification of meteorites. See M. M. Lindstrom, A. H. Treiman, and D. W. Mittlefehldt, “Pigeonholing Planetary Meteorites: The Lessons of Misclassification of EET87521 and ALH84001,”
Lunar and Planetary Science,
vol. 25 (1994): pp. 797–98. It suggested that they and their fellow rock detectives had been too quick to “pigeonhole” rocks in rigid little categories. “If we had opened our minds, . . . might we have discovered ALH84001 sooner?” They noted that certain types of Martian meteorites, even if they fell in Antarctica, might go uncollected because the items would look so much like Earth rocks—so ordinary—to pigeonhole thinkers.

He was still
• Mittlefehldt started out with a fellowship at the space center, then was hired as staff geologist for a NASA support contractor—what is now Lockheed Martin Engineering and Sciences Co. In 2001, he was hired as a NASA scientist.

In the early 1980s
• William A. Cassidy,
Meteorites
(Cambridge: Cambridge University Press, 2003), pp. 159, 229. One achievement of the Antarctic meteorite hunt was the 1982 discovery of the first stone identified as having been catapulted from the moon to Earth. It showed little shock effect, suggesting that debris could, after all, be violently dislodged from a world without melting. This helped to change mainstream thinking on the matter. See also William K. Hartmann,
A Traveler’s Guide to Mars
(New York: Workman, 2003), pp. 258–59, and Steven J. Dick and James E. Strick,
The Living Universe
(New Brunswick, N. J.: Rutgers University Press, 2004), pp. 180–81, regarding Bogard’s work with Pratt Johnson to identify the first Martian meteorite.

Bogard, working at the
• Donald Bogard and Pratt Johnson, “Martian Gases in an Antarctic Meteorite,”
Science
(Aug. 12, 1983): pp. 651–54. Author interview with Bogard. See also Harry Y. McSween, Jr.,
Stardust to Planets
(New York: St. Martin’s, 1993), pp. 99–100. The oddball rocks, the SNCs, all resembled volcanic rock found on Earth, indicating they had experienced a similar pattern of melting and crystallization. And yet they had apparently crystallized a mere 1.3 billion years ago. This had raised suspicions that these stones could not have come from Earth’s moon or from asteroids, which had cooled billions of years earlier to the point of ceasing their volcanic activity.

Through “guilt by
• Michael Meyer, chief NASA astrobiologist, in interview with Steven Dick, Feb. 4, 1997, NASA archives.

Humanity had finally
• Decades earlier, Gene Shoemaker and other planetary scientists had established the importance of impact cratering throughout history, while Stephen Jay Gould and other biologists published evidence of a stepwise history of evolutionary change called punctuated equilibrium. (See Gould, “The Evolution of Life on the Earth,”
Scientific American,
vol. 271 [Oct. 1994]: pp. 85–91.) In 1979, Luis and Walter Alvarez and colleagues made the crucial identification of extraterrestrial material at the boundary layer separating the Cretaceous and Tertiary periods of geological history—evidence that the impact of a comet or asteroid at least six miles (ten kilometers) across had triggered the mass extinction that ended the age of the dinosaurs. Soon afterward, mainstream science accepted the notion of short-term catastrophic changes in geological and biological history. Scientists had linked the course of biological evolution on Earth to the planet’s cosmic environment.

In the dinosaur extinction event, at least half of all Earth’s species swiftly vanished. That extinction event cleared the decks for the advance of the weaselly mammals that were the early ancestors of humans.

The largest space rock encounter in the last century was the 1908 explosion of a huge fireball about four miles above Siberia, releasing the force of one thousand atomic bombs like the one dropped on Hiroshima and flattening evergreen forests in the Tunguska region. About once a month, according to declassified data from military satellites, some extraterrestrial object detonates at high altitude with the force of a kiloton or more of TNT.

Human awareness of
• Several groups of “killer rock” specialists around the world began to mount modest efforts to detect and possibly fend off a pending catastrophic collision. They estimated at least a couple of thousand objects larger than six-tenths of a mile (one kilometer) in diameter were on trajectories that could someday intersect with Earth’s. So far only a fraction of those had been detected, none of them known to pose a threat, according to NASA.

The experts said it would take an object at least a mile in diameter to cause global damage and disrupt civilization. They estimated the odds that such a killer rock would smash into Earth in the next century at slightly less than one in one thousand—cause for study and alertness, but not alarm.

In this context
• The idea that meteorites might deliver life to Earth had been around since 1834. William Thompson (Lord Kelvin) in his “Presidential Address to the British Association for the Advancement of Science,”
Nature
(Aug. 3, 1871): pp. 262–70, made passing reference to the probability “that there are countless seed-bearing meteoric stones moving about through space”; see also Steven J. Dick,
The Biological Universe
(Cambridge: Cambridge University Press, 1996), p. 326.

The Swedish chemist Svante Arrhenius proposed a variation called panspermia in 1901, suggesting that isolated biological spores drifted among the stars. If these kernels of life fell on a suitable world, they might evolve and thrive there. Late in the twentieth century, scientists focused instead on fresh evidence that space was full of traveling bits of prebiotic chemicals—building blocks of life rather than life itself. See Dick,
Biological Universe,
pp. 324–30, 341, 348, 351, 366–77; see also Donald Goldsmith and Tobias Owen,
The Search for Life in the Universe,
3rd ed. (Sausalito, Calif.: University Science, 2001), pp. 196–97.

A series of spaceflight experiments indicated that certain microbes were capable of surviving prolonged exposure to the vacuum of space. In the late 1980s, Gerda Horneck and colleagues at the German space organization DLR flew spores (a dormant state of
Bacillus subtilis,
a common, harmless organism found in soil and fresh water on Earth) aboard NASA’s Long Duration Exposure Facility (LDEF) spacecraft, which stayed in space for six years. They found an 80 percent survival rate in the vacuum—if the spores were shielded from radiation. Beginning in 1994, microbiologist Rocco Mancinelli, of the SETI Institute in California, collaborated with Horneck using flights of the European Space Agency’s Biopan experiment, launched on Russian Foton rockets. Their small experiment would suggest that hardy salt-loving microbes found in Baja California might eke out a small survival rate—just a few percent of the specimens—during a two-week exposure to the vacuum of space and ultraviolet radiation. Horneck found that the most damage, especially during the short term, came from ultraviolet radiation, “but heavy ionizing radiation had a greater probability of being lethal.” See Kathy Sawyer, “Hardy Microbes Appear Able to Survive in Space,”
Washington Post,
Oct. 4, 1999, p. A11; see also R. L. Mancinelli et al., “Biopan-Survival I: Exposure of the Osmophiles
Synechococcus sp.
(nageli) and
Haloarcula sp.
to the Space Environment,”
Advanced Space Research,
vol. 22, no. 3 (1998): pp. 327–34; G. Horneck, G. H. Bücker and G. Reitz, “Long-Term Survival of Bacterial Spores in Space.”
Advanced Space Research,
vol. 14, no. 10 (1994): pp. 41–45; and G. Horneck, “Responses of
Bacillus subtilis
Spores to Space Environment: Results from Experiments in Space,”
Origins of Life,
vol. 23 (1993): pp. 37–52.