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NEAR Near-Infrared Spectrometer (NIS)

NSSDCA ID: 1996-008A-06

Mission Name: NEAR Shoemaker
Principal Investigator:Dr. Joseph F. Veverka

Description

The near-infrared spectrometer (NIS) will be used to study the composition of surface minerals by measuring diagnostic silicate spectral features using reflected sunlight. This will allow determination of the rock types exposed on the asteroid. Combined with information from the X-ray/Gamma-ray Spectrometer and the Multispectral Imager, these data will provide information on the formation and evolution of asteroids and the link between asteroids and meteorites. 433 Eros is near the middle of the wide spectral range of S-class asteroids, which appear to be composed primarily of olivine, pyroxene and iron-nickel. The NIS stopped collecting data on 13 May 2000 for unknown reasons after taking more than 50,000 spectra covering 60% of the surface.

The NIS has a spectral range of 800-2700 nm, covered in 64 spatially co-registered spectral channels. A 1-D gold scan mirror allows the NIS field of view to be boresighted with the Multispectral Imager or scanned up to 140 degrees on one axis. Mirror scanning combined with spacecraft motion will allow full 2-D pointing and the building up of hyperspectral images. A slit and shutters provide a field of view of either 0.38 x 0.76 or 0.76 x 0.76 degrees. The spectrum is dispersed off a diffraction grating onto two detectors, a 32-element germanium (Ge) line-array detector which measures wavelengths from 804-1506 nm in 21.6 nm increments and a 32 element indium gallium arsenide (InGaAs) line array detector which measures wavelengths from 1348 - 2732 nm in 43.1 nm increments. The gain of the Ge detector can be amplified 10x depending on illumination conditions. For on-board, real-time radiometric calibration, the NIS has a solar-illuminated gold target.

The mass of the spectrometer itself is 10.15 kg and it uses 4.3 W of power. The supporting electronics have a mass of 5.0 kg and consume 10.8 W. The operating temperature is <-30 C with a signal to noise ratio greater than 200. Data will be saved with 12-bit resolution per channel, summable to 16 bits. The integration time is one second, on-board summation of up to 16 spectra is possible. The NIS has a surface spot resolution 650 x 1300 m from 100 km range and has collected data during approach, flyby, and from orbit.

Alternate Names

  • NEARShoemaker/NIS
  • NIS

Facts in Brief

Mass: 15.15 kg
Power (avg): 15.1 W

Funding Agency

  • National Aeronautics and Space Administration (United States)

Discipline

  • Planetary Science: Small Bodies

Additional Information

Questions and comments about this experiment can be directed to: Dr. David R. Williams

 

Personnel

NameRoleOriginal AffiliationE-mail
Dr. Joseph F. VeverkaTeam LeaderCornell Universityjfv4@cornell.edu
Dr. Guenter E. BruecknerTeam MemberUS Naval Research Laboratory
Dr. Clark R. ChapmanTeam MemberPlanetary Science Institutecchapman@swri.edu
Dr. Michael C. MalinTeam MemberMalin Space Science Systems, Incmalin@msss.com
Dr. Peter C. ThomasTeam MemberCornell University
Dr. Lucy-Ann McFaddenTeam MemberUniversity of Marylandmcfadden@astro.umd.edu
Dr. Mark S. RobinsonTeam MemberUS Geological Surveyrobinson@sirius.wr.usgs.gov
Prof. James F Bell, IIITeam MemberCornell Universityjfb8@cornell.edu

Selected References

  • Warren, J. W., et al., Near infrared spectrometer for the Near Earth Asteroid Rendezvous mission, Space Sci. Rev., 82, No. 1-2, 101-167, 1997.
  • Izenberg, N. R., et al., In-flight calibration of the Near Earth Asteroid Rendezvous mission's Near Infrared Spectrometer I. Initial calibrations, Icarus, 148, No. 1, 550-571, Jan. 2000.
  • Bell, J. F., III, et al., Near-IR reflectance spectroscopy of 433 Eros from the NIS instrument on the NEAR mission I. Low phase angle observations, Icarus, 155, No. 1, 119-144, Jan. 2002.
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