3.5% 0.007% 0.015%

6 7 8 16 18 C N O S Ar Credit: NASA Sources: Basilevsky and Head (2003). Reports on in , Vol. 66. Bertaux et al. (2007). , Vol. 450. VENUS LunarDR. and ALLANPlanetary Institute TREIMAN

Dr. Allan Treiman is a Senior Staff Scientist and current Associate Director The of Venus, photographed by the 13 . of at the Lunar and Planetary Credit: Don Mitchell (mentallandscape.com). Institute (LPI) in Houston, Texas. Treiman Venus is the most dangerous in the solar : its surface is at studies planetary materials, particularly 393°C, hot enough to melt . It’s even hotter than the planet , which rocks and . is closest to the . Venus’ atmosphere is acidic and thick. Its , which From these rocks, he teases out the hide the surface from view, contain concentrated — strong enough early of the terrestrial to dissolve most used to make spacecraft. The atmosphere is nearly (including large ), emphasizing as thick as because its surface is extremely high — 93 their : water, halogens, carbon, the pressure of ’s atmosphere. But there is no water on Venus and etc. His background is in chemistry, and only small, trace amounts of water in its atmosphere. Acting together, , he approaches planetary from acid, and pressure allow only the strongest spacecraft to survive on the surface both geological and thermochemical of Venus. The United States sent four landers to Venus as part of the Pioneer perspectives. Treiman’s earlier work Venus mission; three crashed to the surface, and the fourth survived for only includes such diverse topics as -atmosphere interactions on Venus; one . From 1967 to 1985, the sent 10 spacecraft to Venus’ in , as revealed by and carbonate in martian surface. All survived just long enough to send some data back to Earth, and meteorites; metamorphism in large water-rich asteroids; and water-deposited none survived longer than two . The photos that were sent to Earth show minerals on the . His current work emphasizes Mars mineralogy a rubbly surface made of . Surprisingly, Venus has not always been (as a Co-Investigator with the CheMin instrument on the rover), so dangerous. The best evidence now shows that Venus once had enough volatiles in the lunar crust, the origins of martian , and serpentinization water to form , so it must have been cooler and much less acidic. It is in relation to . This research core has spun off work in other fi elds possible that Venus was habitable then, or even had ! Why did Venus get so of . Work on the martian Allan Hills (ALH) 84001 led hot and lose its ? No one knows for sure, but many scientists are trying to studies of terrestrial analogs, the Mars Analog Svalbard Expedition to understand why Venus’ changed. (AMASE) expeditions to Spitzbergen , and astrobiology. Work on water in martian meteorites led to investigations of possible surface indicators of Mars water, the martian gullies. Treiman is also active in science education. He has worked in many teacher-training fi eld experiences on volcanology (central Oregon, Yellowstone, and the Cascade ), extreme environments (Owens , California, and Yellowstone), and general geology (northern and New Mexico).

Founded at the height of the program in 1968, the Lunar and Planetary Institute (LPI) is an The 2019 marks the 150th anniversary of Dmitri Mendeleev’s development of the Periodic intellectual leader in lunar and planetary science. LPI’s mission is to advance understanding of the System and has been proclaimed the “International Year of the Periodic of Chemical by providing exceptional science, service, and inspiration to the . The research Elements” (IYPT2019). carried out at LPI supports NASA’s eff orts to explore the solar system. www.iypt2019.org www.lpi.usra.edu