Story ideas and sources: 30th anniversary of Apollo 11

University of Chicago scientists played key roles in the analysis of the Apollo lunar samples and in some of the robotic lunar Surveyor missions that preceded them. Ironically, their findings often conflicted with a prevailing theory of the moon’s origin championed by Nobel laureate Harold Urey, who was then a former University of Chicago professor. Several of these scientists still conduct space-related research at the University. See below for a sample of the Chicago ideas and sources who are available to comment on issues pertaining to the 30th anniversary of the Apollo 11 moon landing, which occurred on July 20, 1969.

Chicago experiment revealed lunar composition before Apollo 11
University of Chicago chemistry Professor Anthony Turkevich and his team learned what the lunar Sea of Tranquillity was made of even before he obtained lunar samples from Apollo 11 in late 1969.

Turkevich was able to analyze the lunar soil through his alpha scattering experiment aboard the robotic Surveyor V space probe, which landed on the moon on Sept. 10, 1967. Turkevich and his team found basalt––volcanic rock––laced with 2 percent titanium at the site. Yet many scientists were initially very skeptical of the results.

“Our analyses were based on a new method and there was some question whether the method was appropriate or not,” said Turkevich, the James Franck Distinguished Service Professor Emeritus in Chemistry at Chicago, who turns 83 on July 23. Thanasis (Tom) Economou, Senior Scientist at Chicago’s Enrico Fermi Institute, said the moon’s titanium content was one of the findings that took experts by surprise. “No basaltic samples here on Earth contain that much titanium,” said Economou, who helped designed and build the alpha scattering experiment in collaboration with Turkevich.

Turkevich and his co-authors, Ernest Franzgrote of NASA’s Jet Propulsion Laboratory and James Patterson of Argonne National Laboratory in Illinois, published their results in the Nov. 3, 1967 issue of the journal Science. They repeated their alpha scattering experiment on Surveyor VI, which landed Nov. 10, 1967, and Surveyor VII, which landed on Jan. 10, 1968, at different locations.

Turkevich’s results were vindicated by the analysis of the Apollo 11 lunar samples. “You should have seen how everyone was then congratulating Turkevich on how well the alpha backscattering instrument did on the moon,” Economou said.

A later version of Turkevich’s alpha scattering instrument, the Alpha Proton X-Ray Spectrometer, successfully performed the first chemical analysis of Martian rocks on board the Mars Pathfinder rover in 1997. APXS instruments also will be part of the Mars 2001 and 2003 Surveyor landing missions. Another related instrument, the Alpha X-ray Spectrometer, will take similar data on asteroid Nereus during the joint U.S.-Japanese MUSES-C mission scheduled for launch in 2002.

For more information, call Thanasis (Tom) Economou at (773) 702-7829. To arrange an interview with Anthony Turkevich, call Steve Koppes at (773) 702-8366.

Farmboy grows up to propose revolutionary theory of moon’s origin
As a child growing up on his father’s farm in Derbyshire, England, during World War II, Joseph Smith used to look up at the moon and wonder why part of it was white and part of it was black.

Years later, Smith, the Louis Block Professor in Physical Sciences at the University of Chicago, found himself conducting tests on Apollo 11 lunar samples. It suddenly dawned on him in early December 1969 that he knew the answer to his boyhood question about the moon’s colors. The white material was rock enriched with the mineral feldspar. The black material was basalt, solidified lava.

The moon was about to give up one of the secrets to its formation. Smith realized that feldspar crystals, being lighter than basalt, probably floated to the highland areas of the moon when the planet was a ball of molten lava. The moon’s crust must have been extensively melted, Smith concluded, in a series of catastrophic meteorite impacts.

“There had to have been tremendous collisions,” said Smith, a member of the National Academy of Sciences. “There’s no way the moon could have got where it was without melting. This was heresy in those days.”

While Smith and his Chicago colleagues worked feverishly on their Apollo 11 lunar samples, they also prepared a moon rock display for the University’s Oriental Institute Museum, a symbolic connection to the early astronomy conducted by the ancient Babylonians. Smith later took the samples to the Field Museum under police escort, where they were again displayed.

“Mayor Daley was supposed to open the exhibit, but it was at the time of the Grant Park riots,” Smith said. So Daley instead sent Jane Byrne, who then was the city’s consumer affairs commissioner. “Jane Byrne was absolutely fascinated by the lunar samples,” Smith said of Chicago’s future mayor. “She closed her eyes before the exhibit, and I guessed that she wished to become mayor.”

Smith’s research interests these days are more Earthbound. Last year, for example, he organized a National Academy of Sciences colloquium on “Geology, Mineralogy, and Human Welfare.”

For more information, e-mail Joseph Smith at psmithAgeo1.uchicago.edu or call Steve Koppes at (773) 702-8366.

Lunar samples shed light on sun’s interior
The Apollo lunar samples intrigued Robert Clayton for the findings they yielded about the sun as well as the moon, findings that remain unexplained to this day.

Clayton, director of the Enrico Fermi Institute and Enrico Fermi Distinguished Service Professor in Chemistry and Geophysical Sciences at the University of Chicago, has examined approximately 300 lunar samples collected during all six Apollo moon landings from 1969 to 1972 and during the Soviet Luna 16 and 20 robotic missions. His measurements of different varieties––isotopes––of oxygen in lunar samples provided surprising evidence supporting the theory that the moon was part of the Earth until a collision with another planet-sized object blasted them apart. But by 1973, Clayton turned his attention to measuring nitrogen isotopes in lunar soils.

Essentially all of the moon’s nitrogen was deposited by the solar wind, a stream of charged particles radiated by the sun, Clayton said. “We were using the moon as a collector of solar material,” he explained. “The material at the bottom of the drill cores was at the surface of the moon two or three billion years ago and therefore records what the sun was doing two or three billion years ago. We have no other way to look at the historical record of the sun,” Clayton said.

Clayton’s analyses turned up an abundance of nitrogen 15, an isotope produced deep within the sun, a product that he never expected to see in the lunar soils.

“The standard models of the sun say that it’s not convecting, it’s not stirring deeply. Materials produced in its interior by its own nuclear reactions are not thought to be coming to the surface, and so we shouldn’t be seeing them in the solar wind. But that still remains, I think, the most plausible source of this excess of nitrogen 15,” he said.

Clayton, with colleagues in the Fermi Institute, in 1973 made one of the first identifications of matter that originated outside the solar system. They also identified the first lunar meteorite in 1983. Now their interest has turned to various sample-return missions to Mars, comets and asteroids.

“Our orientation is to the future, not to the past,” Clayton said.

For more information, call Robert Clayton at (773) 702-7823.

Moon rock coming to Michigan Avenue
Window shoppers on Chicago’s Magnificent Mile soon will be able to peer at a moon rock. The fist-sized lunar sample goes on display Wednesday, July 21, next to the main entrance of the Tribune Tower at 435 N. Michigan Ave.

NASA’s extended loan of the moon rock to the Tribune Company, publisher of the Chicago Tribune, is a first in the space agency’s history.

“No corporation or for-profit organization, so far as we know, has ever been loaned a moon rock for display,” said Lawrence Grossman, Professor in Geophysical Sciences at the University of Chicago. “NASA has only given lunar rocks out for display in museums, planetariums and places like that.”

The display is the culmination of a chance encounter between Jack Fuller, president of the Tribune Company, and Grossman, a meteorite specialist who worked as a graduate student 30 years ago at a Yale University Laboratory funded by NASA for the study of lunar samples. Fuller told Grossman of his dream to display a moon rock at the Tribune Tower when the two men met at a local reception. The Tribune Company then began developing a proposal to NASA for the moon rock display with Grossman and Steven Simon, Senior Research Associate in Geophysical Sciences at Chicago, providing scientific guidance.

The lunar rock was collected during the 1971 Apollo 15 mission to the edge of Mare Imbrium, said Simon, who helped develop the Tribune Tower display. The rock is a basalt, a piece of hardened lava more than 3 billion years old.

The Tribune Tower’s limestone walls are studded with 138 stones and artifacts from around the world, including fragments from India’s Taj Mahal, Egypt’s Great Pyramid of Cheops and Germany’s Berlin Wall. Former Tribune publisher Col. Robert McCormick started the collection in the 1920s.

For more information, call Lawrence Grossman at (773) 702-8153 after July 17 or Steven Simon at (773) 702-8131.

Photos available at http://www-news.uchicago.edu/photos/moon/.