THE JOHN C. LINDSAY MEMORIAL LECTURE
Goddard Space Flight Center
2014 John C. Lindsay Memorial Award Winner
Organics in a Gale Crater Mudstone and the Imprint of
an Ancient Fluvial Environment in 3 Billion Year Old
Water Found in a 4 Billion Year Old Martian Rock "
One Mars year after landing the one-ton Curiosity Rover in Gale Crater, Mars continues to surprise. Data from the Goddard Sample Analysis at Mars (SAM) experiment combined with that from the Alpha Particle X-ray Spectrometer (APXS) has now realized the first in situ chronology experiment implemented on another planet. In addition to establishing the K/Ar formation age of a drilled rock we have been able to measure the deuterium to hydrogen ratio in ancient water vapor locked in clay minerals found in this mudstone. The imprint of extensive atmospheric loss over geological time is evident from this ratio and from complementary measurements of atmospheric isotope ratios in carbon and primordial argon. The search for organic molecules that might address ancient habitability at this site is complicated by the near surface high-energy cosmic radiation that can effectively compromise a molecular carbon record over tens to hundreds of millions of years. Nevertheless, simple chlorinated organic compounds have been clearly identified and measurements of spallation and neutron capture noble gas isotopes have enabled us to establish the duration of the surface exposure this damaging radiation. These measurements provide a protocol for selection of the most promising samples for eventual return to Earth for more detailed examination.
About the Speaker
Paul Mahaffy has participated for many years at Goddard Space Flight Center in study of planetary atmospheres and surface environments and in development of space qualified instrumentation. His main research interests are: (1) Planetary science, especially chemical and isotopic composition of planetary atmospheres and surfaces, (2) Advanced instrument development for organic and light isotope analysis in planetary targets, and (3) Analog studies for martian environments including both laboratory and field work. Paul Mahaffy is the Principal Investigator (PI) on the Sample Analysis at Mars Instrument Suite on the Curiosity Rover currently operating on the surface of Mars. He is also PI on the Neutral Gas and Ion Mass Spectrometer on the MAVEN Mars orbiter mission on its way to Mars and the PI on the Neutral Mass Spectrometer on the LADEE mission that recently finished a very successful mission in lunar orbit exploring the tenuous lunar exosphere. One of his past career highlights was studying the atmosphere of Jupiter using data from a mass spectrometer on the Galileo Probe as it parachuted down into that atmosphere and sent its data back to Earth. He currently is privileged to serve as the Chief of the Planetary Environments Laboratory in the Solar System Exploration Division at NASA Goddard.