Multispectral Resource Sampler: An Experimental Satellite Sensor For The Mid-1980s

An experimental pushbroom scan sensor, called the Multispectral Resource Sampler (MRS), is being developed by NASA for an earth orbiting spacecraft flight in the mid-1980's. This sensor will provide new and unique earth survey research capabilities beyond those possible with current sensor systems, and is designed with flexibility to provide a research facility for a number of preselected experiments. The sensor will have a ground resolution (IFOV) of 15 meters over a swath width of 15 kilometers, in four bands, or 30 kilometers in two bands. A data rate limitation of 15 megabits/second controls the permitted swath width. Each of the four arrays will have five separate spectral filters that will be selectable by command while in orbit. The basic sensor uses four 2000 element detector arrays in the focal plane of a 70 cm focal length (F/3.5) telescope. The four arrays are aligned on a common focal surface; thus no beamsplitters are required. This causes a spatial separation on the ground which requires computer processing to register the bands. A 2.2 ms dwell time of the pushbroom array allows bandwidths as narrow as 20 nanometers over the spectral range from 0.35 to 1.0 micrometers. Response in each band will be quantized into eight bits. The MRS can be pointed at ± 40° in the across track direction and ± 55° in the along track direction. Along track pointing permits stereo coverage at variable base/height ratios and atmospheric correction experiments, while across track pointing will provide repeat coverage, from a Landsat-type orbit, of every 1 to 3 days. A number of significant experiments which could be performed with the MRS include experiments in crop discrimination and status, rock discrimination, geobotanical mineral exploration, land use classification and forestry.