The First Offner Imaging Spectrometers
The very first Offner Imaging Spectrometer ever built was the VIMS-V, which flew onboard the Cassini spacecraft. The Instrument Engineer was Dr. Francis Reininger, now President of SPILAB. The convex grating for the VIMS-V was manufactured by Dr. Klaus Heidemann of Zeiss. The VIMS-V was integrated with the VIMS-IR at JPL. The VIMS-V is shown in the center photograph directly above the VIMS-IR, which is covered in gold MLI. One of the first VIMS spectral images captured at Saturn was the ring image that indicated grain-size and composition.
The second Offner Imaging Spectrometer was the VIRTIS, which flew onboard the Rosetta spacecraft. Dr. Reininger was the Instrument Engineer and optical designer. He invented a new variant of the Offner that combined the visible and infrared channels into one small instrument using a convex, dual band grating. This grating was also manufactured by Dr. Heidemann of Zeiss. The center of the grating diffracted the 250 - 1000 nm spectrum onto a CCD, and the outer annulus diffracted the 900 - 5500 nm spectrum onto a passively cooled, infrared detector array. The VIRTIS combined the dual band Offner Imaging Spectrometer with a High Resolution Echelle Grating Spectrometer. A copy of the VIRTIS flew onboard the Venus Express spacecraft. Its photograph is shown below. In 2002 Dr. Reininger received the NASA Exceptional Scientific and Technical Contribution Award for the development of the Offner Imaging Spectrometer, which was cited as being one of the 100 most important contributions to space science in the decade from 1990 - 2000. He also received the first patent for the Offner Imaging Spectrometer through California Institute of Technology.
SPILAB manufactured a palm sized Offner imaging spectrometer. The convex diffraction grating was manufactured by QUDOS Technology using electron beam milling. The spectrum was diffracted onto a CMOS detector array. A light source could be attached using a fiber optic cable.
