+ Visit NASA.gov + Contact NASA   + Home Select Search Field * All Report - Patent Number Abstract *Accession Number *NASA Center *Author NameDocument IDKeywordsPublication Date *Title * Find Results With All of the words At least one of the words Enter Search Term  within returned results    Search Tips: Use only the fields with * to search NIX collection. Enclose terms in double quotation marks (") to search for exact phrases, ie: "space shuttle". NOTE: Commas and dashes are removed from search term by search engine. Select Reset Search button to start a new search. See Help for more tips. + NASA Center + Publication Year + Subject + Availability Options + Item/Media Type Selected Navigations: Author > Brack, A. [x] Sort results by: NASA Center | Date Added to NTRS | Publication Year There are a total of 4 record(s) matching your query. Sorted by: Date Added To NTRS in Descending order Amino Acid Degradation after Meteoritic Impact Simulation Author(s): Bertrand, M.; Westall, F.; vanderGaast, S.; Vilas, F.; Hoerz, F.; Barnes, G.; Chabin, A.; Brack, A. Abstract: Amino acids are among the most important prebiotic molecules as it is from these precursors that the building blocks of life were formed [1]. Although organic molecules were among the components of the planetesimals making ... NASA Center: Johnson Space Center Publication Year: 2008 Added to NTRS: 2008-04-01 Document ID: 20080012485 Homochirality as the signature of life: the SETH Cigar Author(s): MacDermott, A. J.; Barron, L. D.; Brack, A.; Buhse, T.; Drake, A. F.; Emery, R.; Gottarelli, G.; Greenberg, J. M.; Haberle, R.; Hegstrom, R. A.; Hobbs, K.; Kondepudi, D. K.; McKay, C.; Moorbath, S.; Raulin, F.; Sandford, M.; ... Abstract: A characteristic hallmark of life is its homochirality: all biomolecules are usually of one hand, e.g. on Earth life uses only L-amino acids for protein synthesis and not their D mirror images. It is therefore suggested that ... NASA Center: Ames Research Center Publication Year: 1996 Added to NTRS: 2006-08-02 Document ID: 20040089303 Beta structures of alternating polypeptides and their possible prebiotic significance Author(s): Brack, A.; Orgel, L. E. Abstract: A survey of the commonest amino acids formed in prebiotic conditions suggests that the earliest form of genetic coding may have specified polypeptides with a strong tendency to form stable beta-sheet structures. ... NASA Center: NASA (non Center Specific) Publication Year: 1975 Added to NTRS: 2004-11-03 Accession Number: 75A40124; Document ID: 19750056052 An ESA Robotic Package to Search for Life on Mars Author(s): Westall, F.; Brack, A.; Clancy, P.; Hofmann, B.; Horneck, G.; Kurat, G.; Maxwell, J.; Ori, G. G.; Pillinger, C.; Raulin, F., et al. Abstract: Similarities in the early histories of Mars and Earth suggest that life may have arisen on Mars as it did on Earth. The early life forms on Mars were probably simple organisms, similar to terrestrial prokaryotes. In fact, ... NASA Center: Johnson Space Center Publication Year: 1999 Added to NTRS: 2004-09-16 Document ID: 20000110490 + Back to Top + Sponsored by the NASA Scientific and Technical    Information Program + 2004 Vision for Space Exploration + Freedom of Information Act + NASA Web Privacy Policy and Important Notices + NASA Disclaimers, Copyright Notice,    and Terms and Conditions of Use NASA Official: Calvin Mackey Page Curator: NASA Center for AeroSpace Information (help@sti.nasa.gov) Last Updated: July 5, 2007