Sciences and Exploration Directorate

Melissa Grady Trainer


Melissa Grady Trainer's Contact Card & Information.
Phone: 301.614.6104
Org Code: 699
Mail Code 690
Greenbelt, MD 20771

Missions & Projects

Brief Bio

Dr. Melissa Trainer is a Deputy Principal Investigator (PI) for the Dragonfly mission to Saturn's moon Titan, part of the NASA Planetary Science New Frontiers Program. Dr. Trainer is also the lead for the Dragonfly Mass Spectrometer (DraMS), an instrument supporting the Dragonfly investigation of Titan's surface composition and characterization of potential prebiotic chemistry. Dr. Trainer is also a Co-Investigator and the Deputy Lead for the Venus Mass Spectrometer on the DAVINCI mission to Venus.

Dr. Trainer has been a Research Space Scientist in the Planetary Environments Laboratory at NASA Goddard Space Flight Center since 2009. Her research interests include the composition of planetary atmospheres and the production of organic molecules and aerosols via atmospheric synthesis.

Dr. Trainer has spent more than a decade characterizing the properties of Titan and early Earth aerosol analogs. Her publications on this topic include chemical, optical, and isotopic characterizations of these analogs produced via electric discharge and photochemical irradiation, with recent emphasis on the elemental composition, nitrogen activation, and the influence of trace species such as benzene.

Dr. Trainer is a science team member on the Sample Analysis at Mars (SAM) experiment aboard the Mars Science Laboratory Mission’s Curiosity Rover, with a focus on the compositional measurements of the Mars atmosphere. She has led the campaign to conduct the first in situ multi-year study of the seasonal variations of the composition of the Mars atmosphere through surface mass spectrometry measurements. She also worked with the SAM team to make the first measurements of the full suite of xenon isotopes in the Mars atmosphere as well as the inventory of other noble gases.

Dr. Trainer was a Co-Investigator and Deputy Instrument Scientist for the cryogenic sampling inlet and Neutral Mass Spectrometer on the proposed Titan Mare Explorer (TiME) Mission, which completed Phase A study in 2012. She was a Co-Investigator on the Discovery Candidate DAVINCI Mission to Venus which completed Phase A studies in 2016.

Throughout her career, Dr. Trainer has been active in the NASA Astrobiology community and she participates in several education and public outreach programs. Dr. Trainer has mentored several summer undergraduate students and NASA Postdoctoral Fellows.



Research Space Scientist

NASA Goddard Space Flight Center - Greenbelt, MD

March 2009 - Present

Associate Laboratory Chief, Planetary Environments Laboratory

NASA Goddard Space Flight Center - Greenbelt, MD

December 2017 - May 2020

Assistant Chief for Science, Operations, and Strategic Planning, Planetary Environments Laboratory

NASA Goddard Space Flight Center - Greenbelt, MD

December 2015 - December 2017

NASA Astrobiology Institute Postdoctoral Fellow

NAI at the University of Colorado - Boulder, CO

June 2006 - February 2009

Graduate Research Assistant

University of Colorado - Boulder, CO

August 2000 - May 2006


PhD in Chemistry, University of Colorado, Boulder, CO                    May 2006

Dissertation Title: “Laboratory Studies of Organic Haze Aerosols in Simulated Planetary Atmospheres”

Faculty Advisor:  Prof. Margaret Tolbert

BA in Chemistry, Franklin and Marshall College, Lancaster, PA      May 2000

         Magna Cum Laude, with a minor in Mathematics

Professional Societies

American Geophysical Union (AGU)

2001 - Present

AAS Division of the Planetary Sciences

2014 - Present

American Chemical Society

2000 - Present

Professional Service

  • Session Chair for AbSciCon 2008 and Goldschmidt 2012
  • Organizer of Astrobiology Graduate Science Conference 2007
  • Reviewer of scientific manuscripts for several peer-reviewed journals
  • External reviewer and panel member for several NASA grant programs


  • NASA Honor Group Achievement Award, MSL Prime Mission Science and Operations Team, 2015
  • NASA Early Career Achievement Medal, 2012
  • NASA Astrobiology Institute Postdoctoral Fellowship, 2006 – 2009
  • NASA Graduate Student Researchers Fellowship, 2002 – 2005
  • Award for Excellence in Teaching, Chemistry Department at CU-Boulder, 2001
  • Richard C. Schiedt Trust for Graduate Study, 2000
  • Phi Beta Kappa Honor Society, 2000
  • ACS Analytical Chemistry Award, 1999
  • CRC Freshman Chemistry Award, 1997

Selected Publications


2023. "Characterizing phase transitions for titan's surface molecules: Implications for Dragonfly." Planetary and Space Science 239 (105804): 1-14 [10.1016/j.pss.2023.105804] [Journal Article/Letter]

2023. "Evaluation of the Interference of Tenax®TA Adsorbent with Dimethylformamide Dimethyl Acetal Reagent for Gas Chromatography-Dragonfly Mass Spectrometry and Future Gas Chromatography-Mass Spectrometry in situ Analysis." Journal of Chromatography A 464388 [10.1016/j.chroma.2023.464388] [Journal Article/Letter]

2023. "Comparison of tetramethylammonium hydroxide (TMAH), trimethylsulfonium hydroxide (TMSH), and trimethylphenylammonium hydroxide (TMPAH) thermochemolysis for in situ space analysis of organic molecules in planetary environments." Talanta 257 124283 [10.1016/j.talanta.2023.124283] [Journal Article/Letter]

2023. "Laser Desorption Mass Spectrometry of Cryogenic Samples on the Dragonfly Mission." 2023 IEEE Aerospace Conference [10.1109/aero55745.2023.10115534] [Proceedings]

2023. "Selection and Analytical Performances of the Dragonfly Mass Spectrometer Gas Chromatographic Columns to Support the Search for Organic Molecules of Astrobiological Interest on Titan." Astrobiology 23 (2): 213-229 [10.1089/ast.2022.0038] [Journal Article/Letter]

2022. "Noble Gases and Stable Isotopes Track the Origin and Early Evolution of the Venus Atmosphere." Space Science Reviews 218 (8): 60 [10.1007/s11214-022-00929-9] [Journal Article/Letter]

2022. "Compositional Measurements of Saturn's Upper Atmosphere and Rings From Cassini INMS: An Extended Analysis of Measurements From Cassini's Grand Finale Orbits." Journal of Geophysical Research: Planets 127 (6): [10.1029/2022je007238] [Journal Article/Letter]

2021. "Laser Desorption Mass Spectrometry at Saturn’s moon Titan." International Journal of Mass Spectrometry 470 116707 [10.1016/j.ijms.2021.116707] [Journal Article/Letter]

2021. "Planetary Mass Spectrometry for Agnostic Life Detection in the Solar System." Frontiers in Astronomy and Space Sciences 8 (173): [Full Text] [10.3389/fspas.2021.755100] [Journal Article/Letter]

2021. "Science Goals and Objectives for the Dragonfly Titan Rotorcraft Relocatable Lander." The Planetary Science Journal 2 (4): 130 [10.3847/psj/abfdcf] [Journal Article/Letter]

2021. "Laboratory Studies in Support of the Exploration of Ocean Worlds and NASA Missions." Vol. 53, Issue 4 (Planetary/Astrobiology Decadal Survey Whitepapers) 53 (4): [10.3847/25c2cfeb.935e24ec] [Journal Article/Letter]

2021. "Selection and Characteristics of the Dragonfly Landing Site near Selk Crater, Titan." The Planetary Science Journal 2 (1): 24 [10.3847/psj/abd08f] [Journal Article/Letter]

2020. "Compositional Measurements of Saturn's Upper Atmosphere and Rings from Cassini INMS." Journal of Geophysical Research: Planets 125 (8): [10.1029/2020je006427] [Journal Article/Letter]

2020. "Decomposition of electron ionization mass spectra for space application using a Monte‐Carlo approach." Rapid Communications in Mass Spectrometry 34 (8): [10.1002/rcm.8684] [Journal Article/Letter]

2019. "Seasonal Variations in Atmospheric Composition as Measured in Gale Crater, Mars." Journal of Geophysical Research: Planets 124 (11): 3000-3024 [10.1029/2019je006175] [Journal Article/Letter]

2019. "Hydrogen sensing in Titan's atmosphere: Motivations and techniques." Planetary and Space Science 174 1-7 [10.1016/j.pss.2019.05.010] [Journal Article/Letter]

2018. "Abiotic input of fixed nitrogen by bolide impacts to Gale crater during the Hesperian. Insights from the Mars Science Laboratory." Journal of Geophysical Research-Planets [Full Text] [10.1029/2018JE005852] [Journal Article/Letter]

2018. "Detection Opportunity for Aromatic Signature in Titan’s Aerosols in the 4.1–5.3 μm Range." The Astrophysical Journal 861 (2): L25 [10.3847/2041-8213/aacf88] [Journal Article/Letter]

2018. "Background levels of methane in Mars’ atmosphere show strong seasonal variations." Science 360 (6393): 1093-1096 [10.1126/science.aaq0131] [Journal Article/Letter]

2018. "Strategies for Detecting Biological Molecules on Titan." Astrobiology 18 (5): 571-585 [10.1089/ast.2017.1758] [Journal Article/Letter]

2017. "Influence of trace aromatics on the chemical growth mechanisms of Titan aerosol analogues." Planetary and Space Science 140 27-34 [10.1016/j.pss.2017.03.012] [Journal Article/Letter]

2017. "Initial SAM Calibration Gas Experiments on Mars: Quadrupole Mass Spectrometer Results and Implications." Planetary and Space Science [10.1016/j.pss.2017.01.014] [Journal Article/Letter]

2017. "Environmental temperature effect on the far-infrared absorption features of aromatic-based Titan's aerosol analogs." Icarus 281 338-341 [10.1016/j.icarus.2016.07.015] [Journal Article/Letter]

2016. "The Pale Orange Dot: The Spectrum and Habitability of Hazy Archean Earth." Astrobiology 16 (11): 873-899 [10.1089/ast.2015.1422] [Journal Article/Letter]

2016. "In situ measurement of atmospheric krypton and xenon on Mars with Mars Science Laboratory." Earth and Planetary Science Letters 454 1-9 [10.1016/j.epsl.2016.08.028] [Journal Article/Letter]

2016. "13C and 15N fractionation of CH4/N2 mixtures during photochemical aerosol formation: Relevance to Titan." Icarus 270 421-428 [doi:10.1016/j.icarus.2015.04.016] [Journal Article/Letter]

2016. "Evaluation of the robustness of chromatographic columns in a simulated highly radiative Jovian environment." Planetary and Space Science 122 38-45 [10.1016/j.pss.2016.01.004] [Journal Article/Letter]

2015. "The imprint of atmospheric evolution in the D/H of Hesperian clay minerals on Mars." Science Vol 347 412-414 [[DOI:10.1126/science.1260291]] [Journal Article/Letter]

2015. "Reevaluated martian atmospheric mixing ratios from the mass spectrometer on the Curiosity rover." Planetary and Space Science 109-110 154-158 [doi:10.1016/j.pss.2015.02.014] [Journal Article/Letter]

2014. "Titan aerosol analog absorption features produced from aromatics in the far infrared." Icarus 236 146-152 [10.1016/j.icarus.2014.03.039] [Journal Article/Letter]

2014. "Analytical Techniques for Retrieval of Atmospheric Composition with the Quadrupole Mass Spectrometer of the Sample Analysis at Mars Instrument Suite on Mars Science Laboratory." Planet. Space Sci. [10.1016/j.pss.2014.03.005] [Journal Article/Letter]

2014. "Volatile and Organic Compositions of Sedimentary Rocks in Yellowknife Bay, Gale Crater, Mars." Science 343 6169 [doi:10.1126/science.1245267] [Journal Article/Letter]

2013. "Isotopes of Nitrogen on Mars: Atmospheric Measurements by Curiosity's Mass Spectrometer." Geophys. Res. Lett. 40 6033-6037 [10.1002/2013GL057840] [Journal Article/Letter]

2013. "Abundance and Isotopic Composition of Gases in the Martian Atmosphere from the Curiosity Rover." Science 341 (6143): 263-266 [10.1126/science.1237966] [Journal Article/Letter]

2013. "Volatile, Isotope, and Organic Analysis of Martian Fines with the Mars Curiosity Rover." Science 341 6153 [10.1126/science.1238937] [Journal Article/Letter]

2013. "Primordial Argon Isotope Fractionation in the Atmosphere of Mars Measured by the SAM Instrument on Curiosity and Implications for Atmospheric Loss." Geophys. Res. Lett. 40 5605-5609. [Journal Article/Letter]

2013. "Atmospheric Prebiotic Chemistry and Organic Hazes." Current Organic Chemistry 17 1710- 1723. [Journal Article/Letter]

2013. "The Influence of Benzene as a Trace Reactant in Titan Aerosol Analogs." ApJ Letters 766 L4 [Full Text] [doi:10.1088/2041-8205/766/1/L4] [Journal Article/Letter]

2012. "Nitrogen Incorporation in CH4-N2 Photochemical Aerosol Produced by Far UV Irradiation." Astrobiology 12 315 - 326 [Journal Article/Letter]

2010. "The formation of sulfate and elemental sulfur aerosols under varying laboratory conditions: Implications for Early Earth." 773 - 781 [Journal Article/Letter]

2010. "Enhanced CO2 Trapping in Water Ice via Atmospheric Deposition with Relevance to Mars." Icarus 206 707 - 715 [Journal Article/Letter]

2010. "Optical properties of Titan and early Earth haze laboratory analogs in the mid-visible." Icarus 207 903 - 913 [Journal Article/Letter]

2010. "Limits on the Trapping of Atmospheric CH4 in Martian Polar Ice Analogs." Icarus 208 192 - 197 [Journal Article/Letter]

2009. "Reduction in Haze Formation Rate on Prebiotic Earth in the Presence of Hydrogen." Astrobiology 9 447 - 453 [Journal Article/Letter]

2009. "Measurement of Depositional Ice Nucleation on Insoluble Substrates at Low Temperatures: Implications for Earth and Mars." Journal of Physical Chemistry C 113 2036 - 2040 [Journal Article/Letter]

2006. "Organic Haze on Titan and the Early Earth." Proceedings of the National Academy of the Sciences 103 18035 - 18042 [Journal Article/Letter]

2004. "Chemical Composition of Titan's Haze: Are PAH's present?." Geophysical Research Letters 31 L17S08 [doi:10.1029/2004GL019859] [Journal Article/Letter]

2004. "Haze Aerosols in the Atmosphere of Early Earth: Manna from Heaven." Astrobiology 4 409 - 419 [Journal Article/Letter]

Talks, Presentations and Posters


Titan: An Exotic Ocean World Waiting to be Explored

Library of Congress Video Link:


November 11, 2019

Overview of Saturn's moon Titan and it's interest as an astrobiological target. A brief overview of the Dragonfly mission to Titan.