My background is in signal processing, and my interests lie in astronomy, astrophysics, and planetary science. I entered the doctoral program in the Department of Electrical Engineering at Stanford University in 1983. I joined a research group in the Space, Telecommunications and Radioscience Laboratory (STAR Lab) that was funded at the time by the NASA Search for Extraterrestrial Intelligence (SETI) program. Detection of narrowband radio signals of intelligent extraterrestrial origin represented a very challenging signal processing problem. My research helped lead to the specification of a Multi-Channel Spectrum Analyzer (MCSA) with 10 MHz bandwidth and 15 million frequency channels. My group also developed a custom VLSI processor named the SETI DSP Engine. This device was optimized to quickly perform the Discrete Fourier Transforms required of the MCSA design. It was a proud moment for me years later when I encountered a copy of this chip on display at the National Air and Space Museum in Washington, D.C.

The SETI Institute was founded while I was a doctoral student to increase the research opportunities available with limited SETI funding. I joined the SETI Institute in 1988 following completion of my doctoral degree and worked with a small group to implement a prototype MCSA. The prototype employed dozens of the custom SETI DSP Engines which had now been fabricated and tested. Late in the year we demonstrated a working prototype to our research sponsors and other friends of SETI. A later revision of this spectrum analyzer was employed in the Project Phoenix SETI search at the Institute.

I left the SETI Institute following development and demonstration of the MCSA prototype to experience life in the commercial sector. I returned to Stanford in 1991 to work with a Radio Science research group in the STAR Lab. Over the following sixteen years, I developed and operated science processing pipelines in support of Radio Science investigations associated with several NASA and ESA planetary missions: Mars Observer, Magellan, Galileo, Mars Global Surveyor, Mars Express, and New Horizons. The investigations focused on planetary atmospheres, ionospheres, surfaces, and gravity fields. My time at Stanford concluded following the retirement of my long-time supervisor and the heartbreaking loss of communication with the Mars Global Surveyor spacecraft.

I rejoined the SETI Institute in 2007 to work on the Kepler Mission. The mission involved measuring the brightness of roughly 170,000 stars continuously for four years and searching the stellar light curves for signatures of transiting planets (including Earth-size planets orbiting in the habitable zone of Sun-like stars). I began my involvement with Kepler as a Senior Scientific Programmer in the Science Operations Center (SOC) at the NASA Ames Research Center, and after a few years I became the Lead Scientific Programmer. The SOC was responsible for designing, implementing, operating, maintaining, and documenting the Kepler Science Data Processing Pipeline. The Kepler Mission was fabulously successful and has revolutionized the world of exoplanet science. In recognition of our effort, the Kepler SOC was awarded the NASA Software of the Year Award in 2010.

Kepler focused on a rich star field. More than half of the nearly 6000 known exoplanets as of March 2025 were discovered by Kepler (and the follow-on K2 Mission after spacecraft hardware failures restricted observations to the plane of the ecliptic). The Kepler target stars were distant by design, however, and not particularly amenable to follow-up investigation. The Transiting Exoplanet Survey Satellite (TESS) was selected for flight by NASA in 2013. TESS was the next step after Kepler in the exoplanet mission plan at NASA. The spacecraft launched in April 2018 and science operations commenced three months later.

In the two-year primary mission and two subsequent extended missions, TESS has surveyed most of the sky in search of exoplanets transiting the brightest, and generally nearest stars. Follow-up observations of thousands of exoplanet candidates have been performed with ground-based observatories to better characterize the target stars, attempt to confirm the planetary nature of the candidates, and determine the planet masses where possible. The cream of the exoplanet crop is observed with the James Webb Space Telescope (JWST) to probe the existence and composition of the planetary atmospheres. Subsequent missions will seek to detect biomarkers in exoplanet atmospheres.

I am currently the Lead Data Scientist in the TESS Science Processing Operations Center (SPOC) at NASA Ames Research Center. We developed and now operate the TESS SPOC Science Pipeline based largely on the heritage of the Kepler Pipeline. By the end of the second extended mission in September 2025, 97% of the sky will have been surveyed in at least one observation sector (lasting typically 28 days), 84% of the sky will have been observed at least twice, and 68% of the sky at least three times. Over 600 exoplanets have been discovered with TESS as of March 2025, and nearly 5000 candidates remain to be confirmed. The follow-up observation process is ongoing, and a proposal has been submitted to NASA for a new three-year extended mission. Forty stars hosting one or more planets discovered with TESS (and roughly ten stars hosting planets discovered with Kepler/K2) have been targeted by JWST. Meanwhile, the ongoing TESS survey permits discovery of smaller planets and cooler planets with longer orbital periods. The SPOC Pipeline continues to hum, and the future of exoplanet discovery and characterization should remain bright!

• NASA Ames Honor Award (2014)“For excellence in the category of contractor employee.”
• NASA Certificate of Appreciation (2011) "For exceptional contributions and leadership in the development of the Kepler data analysis tools.”
• NASA Software of the Year Award (2010)Group award for Kepler Science Operations Center (SOC) Science Processing Pipeline.
• Stanford University School of Engineering Dean’s Award (1997)“For his major role and contributions to the Mars Global Surveyor Mission and other STARLab projects, for his outstanding technical judgment and acumen, and for his excellent representation to outside sponsors.”

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