Sciences and Exploration Directorate

John C Brasunas



Org Code: 693

Mail Code: 693
Greenbelt, MD 20771

Employer: EMERITUS

Brief Bio

 Since 1984, my work at NASA has concentrated on the development and operation of Fourier transform spectrometers (FTS) for the study of planetary atmospheres via passive, infrared remote-sensing.  FTS instruments enable us to estimate temperatures, winds, and the types of gasses present (including isotopes).  This capability is also relevant to the characterization of global climate systems.  My more substantive roles have been in the following projects.


Balloon-borne/ground-based spectroscopic observations of Earth atmosphere with the SIRIS FTS.

SIRIS, a cryogenic mid-infrared FTS developed by Virgil Kunde, was flown on high-altitude balloons to study the stratospheric ozone cycle, and was operated at a ground-based site as part of a field campaign to help improve the agreement between observations and models of radiative imbalances critical to the global climate system.  I served as a co-I.

Spectroscopic studies of the Jovian and Saturnian systems with the CIRS FTS aboard the Cassini orbiter

The CIRS spectrometer (also developed by Virgil Kunde) was launched to Saturn in 1997 as part of the Cassini mission, with a Jupiter flyby on December 30, 2000.  Arrival at Saturn was in July, 2004, followed by a final plunge into the Saturnian atmosphere in September 2017.  I was responsible for the design, development, delivery and integration of the flight hardware for the long wavelength channel.  This included cultivating a source in then West Germany for the thermoelectric detectors no longer available in the United States.  After launch, I continued as part of the calibration team.  I served as a co-I.

Development of high temperature superconductor (HTS) bolometers needing only moderate cooling

Since the late 1980’s I have been working to develop infrared detectors using HTS materials, first YBCO with a transition temperature near 87K, and then (starting around 2001) MgB2 with a transition temperature near 38K.  The production of HTS bolometers would enable us to introduce more sensitive long-wavelength detectors to future FTS instruments for planetary missions.  I served as PI, with substantial and sustained funding from NASA HQs through the PIDDP program.

Development of a smaller, lighter FTS known as CIRS-lite

To reduce the size and mass of the CIRS FTS for missions following Cassini, I have pursued technical advances in HTS bolometers, CVD diamond beam-splitters, double-passed cube-corners for the FTS moving mirror, and telescopes with innovative materials such as carbon composites.  I developed CIRS-lite as a breadboard and then a flight-like brassboard with proven performance at cryogenic temperature (77 K).  I served as PI, with substantial and sustained funding through the PIDDP program.