The Emirates Mars Mission (EMM) Emirates Mars InfraRed Spectrometer (EMIRS) Instrument

Christopher S. Edwards, Philip R. Christensen, Greg L. Mehall, Saadat Anwar, Eman Al Tunaiji, Khalid Badri, Heather Bowles, Stillman Chase, Zoltan Farkas, Tara Fisher, John Janiczek, Ian Kubik, Kelly Harris-Laurila, Andrew Holmes, Igor Lazbin, Edgar Madril, Mark McAdam, Mark Miner, William O’Donnell, Carlos OrtizDaniel Pelham, Mehul Patel, Kathryn Powell, Ken Shamordola, Tom Tourville, Michael D. Smith, Nathan Smith, Rob Woodward, Aaron Weintraub, Heather Reed, Emily B. Pilinski

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

The Emirates Mars Mission Emirates Mars Infrared Spectrometer (EMIRS) will provide remote measurements of the martian surface and lower atmosphere in order to better characterize the geographic and diurnal variability of key constituents (water ice, water vapor, and dust) along with temperature profiles on sub-seasonal timescales. EMIRS is a FTIR spectrometer covering the range from 6.0-100+ μm (1666-100 cm−1) with a spectral sampling as high as 5 cm−1 and a 5.4-mrad IFOV and a 32.5×32.5 mrad FOV. The EMIRS optical path includes a flat 45° pointing mirror to enable one degree of freedom and has a +/- 60° clear aperture around the nadir position which is fed to a 17.78-cm diameter Cassegrain telescope. The collected light is then fed to a flat-plate based Michelson moving mirror mounted on a dual linear voice-coil motor assembly. An array of deuterated L-alanine doped triglycine sulfate (DLaTGS) pyroelectric detectors are used to sample the interferogram every 2 or 4 seconds (depending on the spectral sampling selected). A single 0.846 μm laser diode is used in a metrology interferometer to provide interferometer positional control, sampled at 40 kHz (controlled at 5 kHz) and infrared signal sampled at 625 Hz. The EMIRS beamsplitter is a 60-mm diameter, 1-mm thick 1-arcsecond wedged chemical vapor deposited diamond with an antireflection microstructure to minimize first surface reflection. EMIRS relies on an instrumented internal v-groove blackbody target for a full-aperture radiometric calibration. The radiometric precision of a single spectrum (in 5 cm−1 mode) is <3.0×10−8 W cm−2 sr−1/cm−1 between 300 and 1350 cm−1 over instrument operational temperatures (<∼0.5 K NEΔ T @ 250 K). The absolute integrated radiance error is < 2% for scene temperatures ranging from 200-340 K. The overall EMIRS envelope size is 52.9×37.5×34.6 cm and the mass is 14.72 kg including the interface adapter plate. The average operational power consumption is 22.2 W, and the standby power consumption is 18.6 W with a 5.7 W thermostatically limited, always-on operational heater. EMIRS was developed by Arizona State University and Northern Arizona University in collaboration with the Mohammed bin Rashid Space Centre with Arizona Space Technologies developing the electronics. EMIRS was integrated, tested and radiometrically calibrated at Arizona State University, Tempe, AZ.

Original languageEnglish (US)
Article number77
JournalSpace Science Reviews
Volume217
Issue number7
DOIs
StatePublished - Oct 2021

Keywords

  • Atmosphere
  • EMM
  • Emirates Mars Infrared Spectrometer
  • Mars

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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