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Stephen C. Unwin

Photo of Stephen Unwin


4800 Oak Grove Drive
M/S 301-170S

Pasadena, CA 91109





Curriculum Vitae:

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Member of:


Principal Scientist


Dr. Unwin received his BA, MA, and PhD degrees from the University of Cambridge, and was a postdoctoral fellow and a Member of the Professional Staff at Caltech. He researched active galactic nuclei using VLBI and X-ray instruments and contributed to techniques for sparse-aperture imaging. For several years he was manager of the VLBI correlator, an essential component of the VLBI imaging system. His experience ranges from working with telescopes and instrumentation at OVRO, Parkes, Palomar, CSO, VLA, and VLBA, and with the ROSAT, FERMI, and Kepler spacecraft.

Steve moved to JPL in 1996 to work on the Space Interferometry Mission, and was Deputy Project Scientist for the project during its long development. He served as Deputy Program Scientist for the Exoplanet Exploration Program for several years, working extensively with community-based science teams. He has extensive experience in end-to-end mission concept development, and has led several mission proposals to NASA. Most recently, he served as Proposal Manager on the SPHEREx mission, approved in Oct 2020 to enter Implementation (Phase C).

Dr. Unwin is Vice President of the American Astronomical Society (2020-2023), and also served on the Board of Directors (2014-17), responsible for planning the annual scientific meetings. He is a Fellow of the Royal Astronomical Society, a member of the AAS Division on Dynamical Astronomy (Chair 2006-7), a member of the International Scientific Radio Union, and a member of the International Astronomical Union.


  • PhD, Radio Astronomy, University of Cambridge (1979)
  • BA, Physics and Theoretical Physics, Clare College, Cambridge (1976)

Professional Experience

  • Jet Propulsion Laboratory (1996-Present)
    • Principal Scientist (2001-present)
    • Deputy Program Scientist, Exoplanet Exploration Program (2004-2015)
    • Deputy Director, JPL Center for Exoplanet Science (2006-2011)
    • Deputy Project Scientist, Space Interferometry Mission (1996-2010)
    • Section Staff, Interferometry and Large Optical Systems Section (2001-2008)
    • Deputy Project Scientist, Terrestrial Planet Finder Interferometer (2004-2007)
  • California Institute of Technology, Pasadena, Calif. (1980-1996)
    • Research Fellow and Member of the Professional Staff (1980-1996)
    • Manager of the VLBI Correlator (1984-1995)

Community Service

  • Vice President, American Astronomical Society (2020-2023)
  • Member of Board of Directors, American Astronomical Society (2014-17)
  • AAS Agent for Los Angeles (2016 - present)
  • AAS Agent for Los Angeles (2016 - present)
  • NASA proposal review panels (1994-2017)
  • Brouwer Award Selection Committee Chair, Division on Dynamical Astronomy of the American Astronomical Society (2010)
  • Division Chair, Division on Dynamical Astronomy of the AAS (2006-2007)
  • NSF Management Review Committee of Arecibo Observatory (2007)
  • NAIC / Arecibo Users Committee, 2000-2003. Committee Chair (2003)
  • NASA Keck Time Allocation Committee (2013)
  • National Science Foundation proposal reviewer (2000-2005)
  • AAS / Division on Dynamical Astronomy, Committee member (2000-2002)
  • National Radio Astronomy Observatory Users Committee, 1992-95. Committee Chair (1995)

Research Interests

  • Astronomy mission concept development and proposals
  • Astronomical instrumentation
  • Extrasolar planets and debris disks
  • Active galactic nuclei

Selected Awards

  • JPL Discovery Award (2017 and 2018)
  • JPL Voyager Award (2017)
  • NASA Group Achievement Award (1993 and 2011)
  • JPL Mariner Award (2011)
  • JPL Explorer Award (2009)
  • JPL Leadership Awards (2000 and 2007)

Selected Publications

  1. Cooray, A. et al. 2019, “CDIM: Cosmic Dawn Intensity Mapper Final Report”, arXiv:1903.03144
  2. Doré, O., et al. (65 co-authors) 2018, “Science Impacts of the SPHEREx All-Sky Optical to Near-Infrared Spectral Survey II: Report of a Community Workshop on the Scientific Synergies Between the SPHEREx Survey and Other Astronomy Observatories”, arXiv: 1805.05489
  3. Doré, O., et al. (67 co-authors) 2016, “Science Impacts of the SPHEREx All-Sky Optical to Near-Infrared Spectral Survey: Report of a Community Workshop Examining Extragalactic, Galactic, Stellar and Planetary Science”, arXiv:1606.07039
  4. Stapelfeldt, K.R., et al. 2015. “Exo-C: a probe-scale space observatory for direct imaging and spectroscopy of extrasolar planetary systems”, SPIE, 10.1117/12.2191720.
  5. Makarov, V.V. & Unwin, S.C. 2015. “Radial velocities and binarity of southern SIM grid stars”, MNRAS, 446, 2055.
  6. Spangelo, S.C., Katti, R.M., Unwin, S.C., & Bock, J.J. 2015, “All-sky survey mission observing scenario strategy”, JATIS, 10.1117/1.JATIS.1.3.037001
  7. Wehrle, A.E., Wiita, P.J., Unwin, S.C., di Lorenzo, P., Revalski, M., Silano, D., & Sprague, D. 2013, "Kepler Photometry of Four Radio-loud Active Galactic Nuclei in 2010-2012", ApJ, 773, 89
  8. Unwin, S.C., and 16 co-authors, 2012, "Coronagraphic Imaging of Debris Disk From a High Altitude Balloon Platform", SPIE, 8442, 84420G
  9. Lawson, P.R., Traub, W.A. & Unwin, S.C. 2009, "Exoplanet Community Report", JPL Publication 09-3 3/2009
  10. Unwin, S.C., et al. (with 35 co-authors) 2008, "Taking the Measure of the Universe: Precision Astrometry with SIM PlanetQuest", PASP, 120, 38
  11. Unwin, S.C. 2005, "Precision Astrometry with the Space Interferometry Mission-PlanetQuest", Astrometry in the Age of the Next Generation of Large Telescopes, ASP Conference Series, 338, 37
  12. Unwin, S.C. and Stachnik, R. (eds.) 2000, "Working on the Fringe: Optical and IR Interferometry from ground and Space", ASP Conference Series, vol. 194, pp. 1-485
  13. Jenet, F.A., Anderson, S.B., Kaspi, V.M., Prince, T.A., & Unwin, S.C. 1998, "Radio Pulse Properties of the Millisecond Pulsar PSR J0437-4715", ApJ, 498, 365
  14. Unwin, S.C., Wehrle, A.E., Urry, C.M., Gilmore, D.M., Barton, E.J., Kjerulf, B.C., Zensus, J.A., & Rabaca, C.R. 1994, "Inverse-Compton X-ray Emission from the Superluminal Quasar 3C 345", ApJ, 432, 103
  15. Unwin, S.C. 1983, "Neutral Hydrogen in the Andromeda Nebula", MNRAS, 205,773