Spectroscopy

Imaging spectroscopy -- the acquisition of spectra for every point in an image -- is a powerful analytical method that enables remote material detection, identification, measurement, and monitoring for scientific discovery and application research. From mapping vegetation species on Earth to studying the composition of the intergalactic medium, spectrometers can be used to reveal physical, chemical, and biological properties and processes.

Since its inception in the late twentieth century, spectrometer technology has advanced to where we are now capable of using advanced spectroscopy to understand worlds from the micron scale to exoplanet distances. Spectroscopy provides access to information about molecules, atmospheric conditions, and composition, and it has been used on Earth and throughout the solar system to perform new science research. In the future, spectroscopy of exoplanets could provide the first evidence of life beyond Earth.

AVIRIS Image Cube shows the volume of data returned by the instrument.  The rainbow-colored panels to the top and right of each image represent the different reflected light, or spectral, signatures that underlie every point in the image.

High-fidelity spectrometers with advanced detectors, optical designs, and computation systems are needed to derive information of value from remotely measured spectra. Current research focuses on several key topics:

• Versatility: Increasing both spectral range and swath width would enable future spectrometers to measure the global distribution of atmospheric gases on a daily basis. These versatile instruments would also help meet the mass and power constraints of future missions without compromising performance.
• Optical design: Improved diffraction gratings for tuning efficiency and reducing scattering and polarization sensitivity would lead to higher-quality spectral measurements.
• Real-time algorithms: Onboard cloud screening with negligible false alarms, for example, would lower buffering, transmission, analysis, and curation costs by eliminating unusable data.

In recent years, JPL has developed, tested, and delivered airborne, rover-type and space class imaging spectrometers. Our Moon Mineralogy Mapper spectrometer discovered evidence of low concentrations of water on the illuminated surface of the Moon and was successful at enabling scientists to derive mineralogical properties from its spectral measurements. This and a range of potential future mission for science and applications research has driven our interest in miniaturizing such a system for in situ use on other solar system bodies in the future.

Curled up from; Jet propulsion Laboratory, 

California Institute of Technology