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Summary Overview
Benefits
Contacts
The Multispectral Imaging Capability
(MIC) represents an affordable, straightforward approach to a multispectral
Landsat follow-on instrument with substantially lower mass, volume,
and cost. This technology is directly responsive to the language
of the Land Remote Sensing Policy Act in which NASA is charged to
ensure Landsat data continuity through the use of advanced technology.
The MIC consists of the multispectal and panchromatic components
of the Advanced Land Imager's (ALI) Focal Plane System (FPS) and
the ALI's calibration capability.
Multispectral Panchromatic (MS/Pan) Array: Although the optical system supports a 15° wide FOV, only a small fraction was populated with detector arrays, as illustrated in the diagram below. The intent is to provide adequate flight validation of the imaging technologies, but within the program cost and schedule constraints. The multispectral and panchromatic (MS/Pan) array has 10 m spectral bands in the visible and near infrared (VNIR), and short wave infrared (SWIR). The panchromatic detectors subtend 10 m square pixels on the ground and are sampled every 10 m as the Earth image moves across the array. The MS detectors subtend 30 m and are sampled every 30 m. Four sensor chip assemblies (SCA's) populate a 3° cross-track segment of the focal plane. Each MS band on each SCA contains 320 detectors in the cross-track direction, while the panchromatic band contains 960 detectors. The total cross-track coverage from the MS/Pan module is 37 km.
The MS/Pan arrays use VNIR detectors integrated with the Readout Integrated
Circuit (ROIC). The SWIR detectors, made of mercury-cadmium-telluride
(HgCdTe), promise high performance over the 0.9 to 2.5 µm wavelength
region at temperatures which can be reached by passive or thermoelectric
cooling. The nominal focal plane temperature is 220 K and is maintained
by the use of a radiator. Application of detectors of different materials
to a single readout integrated circuit (ROIC) enables a large number
of arrays, covering a broad spectral range, to be placed close together.
This technology is extremely effective when combined with the WFOV optical
design being used on ALI. This is due to the fact that, although this
optical design provides a large FOV in the cross-track dimension, the
FOV in the in-track dimension is much smaller.
Multispectral imaging technology has demonstrated
the capability of better calibrated and higher signal-to-noise high spatial
resolution Landsat-type surface measurements. The technology can be incorporated
into a lower cost, smaller, lighter and less power consuming Landsat follow-on
instrument accommodatable on a small spacecraft.
Paul T. Bryant
Principal System Engineer
Raytheon IR CoE
Phone (805) 562-2552
Email: ptbryant@west.raytheon.com
Don Lencioni
Instrument Scientist
MIT Lincoln Laboratory
Phone: (781)981-7996
Email: Lencioni@ll.mit.edu
Cliff W. Nichols
Principal System Engineer
Raytheon IR CoE
Phone (805) 562-2477
Email: cwnichols@west.raytheon.com
Nick Speciale
EO-1 Mission Technologist
NASA's Goddard Space Flight Center
Mail Code: 490
Phone (301) 286-8704
Email: Nicholas.J.Speciale.1@gsfc.nasa.gov
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