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This investigation proposes to fabricate, test, calibrate, and deliver an imaging experiment for the Mars Surveyor '98 Orbiter mission, scheduled for launch in December, 1998. It further proposes to support Mars Surveyor '98 mission operations, to acquire, process, and archive the imaging data, and to provide scientific analyses of the images acquired. The primary objectives of this investigation are to: 1) observe martian atmospheric processes at global scale and synoptically, 2) study details of the interaction of the atmosphere with the surface at a variety of scales in both space and time, and 3) examine surface features characteristic of the evolution of the martian climate over time. These objectives will be met through the acquisition of images over a range of time and spatial scales.
The Mars Surveyor '98 Orbiter Color Imager (Mars Color Imager, or MARCI) consists of two cameras with unique optics and identical focal plane assemblies (FPA), Data Acquisition System (DAS) electronics, and power supplies, developed under Planetary Instrument Definition and Development Program (PIDDP) funding. Each camera is characterized by small physical size (~6 X 6 X 12 cm, including baffle, and < 500 gm), low power requirements (< 2.5 W, including power supply losses), and high science performance (1000 X 1000 pixel, low noise). The system design uses highly-integrated devices to minimize mass and parts count. The camera uses a megapixel, electronically-shuttered CCD, and other electronics parts, tested for flight applications as part of the PIDDP effort. A Digital signal processor (DSP) is used for system control and high-level operation of the detectors, with minimal requirements on the spacecraft central processing unit. Small gate arrays are used for time-critical digital functions and glue logic. The analog processing chain uses analog ASICs for clock generation, and square-root encoding to eliminate the need for gain settings.
The Wide Angle (WA) camera will acquire daily global maps in five spectral bands, including two ultraviolet bands that quantitatively characterize atmospheric ozone, at resolutions no poorer than 7.2 km/pixel under the worst case downlink data rate. Under better downlink conditions, the WA will provide kilometer-scale global maps of atmospheric phenomena such as clouds, hazes, dust storms, and the polar hood. Limb observations will provide additional detail on atmospheric structure at 1/3-scale height resolution. This experiment will complement PMIRR with great synergy.
The Medium Angle (MA) camera is designed to study selected areas of Mars at regional scale. Its 6° field-of-view (FOV), which covers 40 km at 40 m/pixel, was selected to permit all positions of the planet except the rotational poles to be imaged every two mapping cycles (roughly 52 sols), based on the orbit parameters provided in the Proposal Information Package. Ten spectral channels between 425 nm and 1000 nm provide the ability to discriminate both atmospheric and surface features on the basis of composition.
Mission operations benefits greatly from use of capabilities (e.g. operations software), facilities, and personnel at Malin Space Science Systems (MSSS) that have been assembled as part of the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) operations effort. These resources greatly reduce operations cost and complexity, and can be shared with the MGS Mars Relay effort to further reduce cost.
The anticipated results of this investigation include: 1) detailed monitoring of global, regional, and local meteorological processes and phenomena, determined from daily km-scale global multispectral maps, including ozone concentration, 2) regional and local study of eolian and polar processes and landforms as indicators of surface/atmospheric interactions over relatively short timescales, and 3) unit maps indicating surface composition as determined by multi-color observations of iron-bearing minerals and their hydration and oxidation products.
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