NEWS CDF THE WEEK SPACE
SCIENCE
LUNAR PROBE GOES OUT WITH A BANG European Space Agency completes moon mission as craft crashes into lunar surface FULL MOON This image of the lunar surface is one of nearly 20,000 images returned by SMART-1 before it crashed.
T
HE EUROPEAN SPACE AGEN-
cy (ESA) celebrated the completion of its first mission to the moon on Sept. 3 when the spacecraft SMART-1 made its planned impact on the lunar surface. T h e 36month, S141 million project demo n s t r a t e d key technologies that the agency will use in future scientific expeditions. Among the technologies tested on t h e first
CHEMICAL
Small Missions for Advanced Research in Technology (SMART) mission was a solar-electric propulsion system. Its ion engine uses electricity from solar panels to generate a beam of charged particles, which push the spacecraft forward. This demonstration of ion propulsion is a first for ESA. SMART-1 also contained a number of miniaturized instruments to study the formation and evolution of the moon, including a D-CIXS (demonstration of a compact imaging X-ray spectrometer) instrument to study the lunar surface's composition. D-CIXS de-
ARCHAEOLOGY
STILL DYEING AFTER 2,000 YEARS Ancient formula, now re-created, darkens locks with lead sulfide nanoparticles
DARK CRYSTALS Within 72 hours, PbS nanocrystals darken blonde hair (left) to black (right).
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C&EN / SEPTEMBER
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ANOTECHNOLOGY MAY SEEM
like the latest fad in beautyproducts, but a new report suggests that people have been using nanomaterials to improve upon nature for at least 2,000 years. According to researchers in France, an ancient hair-coloring concoction
1 1 . 2006
turns tresses black via the formation of lead sulfide nanoparticles within the hair shaft (Nano Lett., DOL 10.1021/nl061493u). "During the second century C E . , Claudius Galen, the most famous doctor in the Roman Empire, described exactly how to use a mixture of lead oxide and slaked lime [Ca(OH)2] to dye hair black," explains Philippe Walter, a senior scientist at the Paris-based CNRS Research & Restoration Center of Museums in France, who spearheaded the research. Applied as a paste, the lead-based formula strips sulfur from amino acids in the hair's keratin proteins and forms
tects the solar X-rays reflected by the moon. The energy of those Xrays is a function of the abundance of a particular element. T h e scientists are still sifting through the data from D-CIXS (the instrument continued to send data until two seconds before impact); the analyses to date find evidence of magnesium, aluminum, silicon, iron, and calcium, which is consistent with the analysis of moon samples returned by the Soviet Luna program. This result, however, does mark the first time that calcium has been detected remotely on the moon. A similar instrument will fly on India's first lunar mission, Chandrayaan-1, scheduled to launch next year. "SMART-1 data have opened a new era in remote-sensing investigation of Earth's nearest neighbor," said Manuel Grande, D - C I X S principal investigator. "A great deal is still to be learned from analysis of these data," he added.—SUSAN MORRISSEY
darkly colored PbS within the hair. Similar formulas for dyeing hair and wool were recorded during the medieval period and the Renaissance and by 18th-century chemists in France. The coloring product Grecian Formula still uses this lead-based chemistry to gradually darken gray hair. Working in collaboration with scientists at L'Oréal, Walter and colleagues re-created Galen's recipe and studied progressively darkening hair with modern analytical techniques. They found that the PbS forms quantum-dot-like crystals about 5 nm across. "What is particularly surprising in this reaction is that, despite the structural complexity of hair and its relative chemical inertness, metal sulfide nanoparticles easily crystallize and get organized inside this biomaterial," Walter notes. In contrast to modern nanotechnology, Walter adds, the dyeing process uses basic chemistry techniques and inexpensive natural materials.—BETHANY HALF0RD WWW.CEN-0NLINE.ORG
