In-Flight Calibration of the Near Earth Asteroid Rendezvous Mission's Near Infrared Spectrometer I. Initial Calibrations

Izenberg, N. R.; Bell, James F.; Warren, J.; Murchie, S. L.; Peacock, Keith; Darlington, E. H.; Carcich, B.; Chapman, C. R.; Clark, B. E.; Harch, A.; Heyler, Gene A.; Joseph, J.; Martin, Patrick; McFadden, L. A.; Merline, Bill; Robinson, M. S.; Veverka, J.; Wellnitz, D. D.

doi:10.1006/icar.2000.6541

Cited by 12 publications

(19 citation statements)

References 31 publications

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“…This resulted in a decrease of the usable spectral range at the long wavelength end from 2.7 to 2.4 µm. Our study uses the calibrated NIS data; the uncertainties in calibration methods are presented in Izenberg et al (2000) and Warren et al (1997).…”

Section: Observationsmentioning

confidence: 99%

NEAR Infrared Spectrometer Photometry of Asteroid 433 Eros

Clark¹,

Helfenstein²,

Bell³

et al. 2002

Icarus

121

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Section: Observationsmentioning

confidence: 99%

NEAR Infrared Spectrometer Photometry of Asteroid 433 Eros

Clark¹,

Helfenstein²,

Bell³

et al. 2002

Icarus

121

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“…Spectroscopic data used for this analysis have been calibrated (Izenberg et al, 2000) and photometrically corrected . Calibration procedures correct instrumental fluxes for the effects of dark current, detector crosstalk, and bias.…”

Section: Near-infrared Spectroscopymentioning

confidence: 99%

“…5 the plate model is shaded according to the photometrically corrected normal albedo values at 0.946pm and reprojected to a simple cylindrical map. Thus, although the spectrometer footprint is rectangular in shape (Izenberg et al, 2000), resolution elements in our coverage maps are triangular in shape because we use a plate model of Eros. Each plate is covered at least 80% by the specified spectrum.…”

Section: Average Spectral Propertiesmentioning

confidence: 99%

Space weathering on Eros: Constraints from albedo and spectral measurements of Psyche crater

Clark

Lucey

Helfenstein

et al. 2001

Meteorit & Planetary Scien

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Abstract-We present combined multi-spectral imager (MSI) (0.95 pm) and near-infrared spectrometer (NIS) (0.8-2.4pm) observations of Psyche crater on S-type asteroid 433 Eros obtained by the NearEarth Asteroid Rendezvous (NEAR)-Shoemaker spacecraft. At 5.3 km in diameter, Psyche is one of the largest craters on Eros which exhibit distinctive brightness patterns consistent with downslope motion of dark regolith material overlying a substrate of brighter material. At spatial scales of620 m/ spectrum, Psyche crater wall materials exhibit albedo contrasts of 3 2 4 0 % at 0.946 pm. Associated spectral variations occur at a much lower level of 4-8% (+2-4%). We report results of scattering model and lunar analogy investigations into several possible causes for these albedo and spectral trends: grain size differences, olivine, pyroxene, and troilite variations, and optical surface maturation. We find that the albedo contrasts in Psyche crater are not consistent with a cause due solely to variations in grain size, olivine, pyroxene or lunar-like optical maturation. A grain size change sufficient to explain the observed albedo contrasts would result in strong color variations that are not observed. Olivine and pyroxene variations would produce strong band-correlated variations that are not observed. A simple lunar-like optical maturation effect would produce strong reddening that is not observed. The contrasts and associated spectral variation trends are most consistent with a combination of enhanced troilite (a dark spectrally neutral component simulating optical effects of shock) and lunar-like optical maturation. These results suggest that space weathering processes may affect the spectral properties of Eros materials, causing surface exposures to differ optically from subsurface bedrock. However, there are significant spectral differences between Eros' proposed analog meteorites (ordinary chondrites and/or primitive achondrites), and Eros' freshest exposures of subsurface bright materials. After accounting for all differences in the measurement units of our reflectance comparisons, we have found that the bright materials on Eros have reflectance values at 0.946pm consistent with meteorites, but spectral continua that are much redder than meteorites from 1.5 to 2.4 pm. Most importantly, we calculate that average Eros surface materials are 3040% darker than meteorites.

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“…The instrument carries an onboard diffuse gold calibration target for periodic monitoring of its stability. Additional details on the preflight and inflight calibration and performance of the NIS can be found in Warren et al (1997) and Izenberg et al (2000a).…”

Section: Introductionmentioning

confidence: 99%