NOMAD (Nadir and Occultation for Mars Discovery)

ODE: Mars

Mission: ESA's ExoMars Trace Gas Orbiter

Instrument:NOMAD

Instrument Team Site: NOMAD Team Web Site

PDS4 Bundle: urn:esa:psa:em16_tgo_nmd

Search ExoMars Trace Gas Orbiter NOMAD data in Mars ODE: Product Search • Map Search

The Nadir and Occultation for MArs Discovery (NOMAD) instrument is a spectrometer suite led by the Belgian Institute for Space Aeronomy (BIRA-IASB), being flown on the ESA/Roscosmos ExoMars Trace Gas Orbiter mission. NOMAD is predominantly based upon the SOIR-channel (Solar Occultations in the Infrared) in the SPectroscopy for the Investigation of the Composition of the Atmosphere of Venus instrument (SPICAV) from the highly successful Venus Express mission, a compact high-resolution echelle grating spectrometer with acousto-optical tunable filter for the infrared domain between 2.3 and 4.3 μm.

NOMAD consists of three separate channels, Solar Occultation (SO), Limb Nadir and Occultation (LNO) and Ultraviolet and VIsible Spectrometer (UVIS), all controlled via a single main electronics unit (SINBAD).

NOMAD characteristics and performances

  SO Channel

LNO Channel

UVIS Channel
Detector

2D HgCdTe 320x256 pixel FPA

2D HgCdTe 320x256 pixel FPA

 2D 1024x256 pixel CCD
Detector temperature 88 K

88 K

 N/A
Line of Sight periscope lining up with Sun direction

Periscope for lining up with Sun direction – Nadir viewing entrance

 2 telescopes lining up with Sun and nadir directions
Spectral range 2.3 -4.3 μm

2.3 - 3.8 μm

 200-650 nm

Resolving power Resolution

20000 0.15-0.22 cm-1

10000 0.3-0.5 cm-1

1-2 nm

Instantaneous field of view (spectral x spatial)

2 arcmin x 30 arcmin

4 arcmin x 150 arcmin

2 arcmin (solar occ)
43 arcmin (nadir)

Spatial resolution

Instantaneous footprint

1 km (Δz at limb)

1 km (Δz at limb)
0.5 km x 17 km

1 km (Δz at limb)
5 km x 5 km (Nadir)

Vertical sampling

180 m to 1 km

180 m to 1 km

< 300 m

 

TGO NOMAD Products have been archived in PDS4 standard. They are grouped into PDS4 collections based on processing level.

PDS4 Collection

Processing Level Description

PDS4 Bundle

Raw Data

Raw data products from science telemetry packets, in the form of ASCII tables.

urn:esa:psa:em16_tgo_nmd:data_raw

Partially Processed Data

Housekeeping corrected data

Detector corrections (linearity, dark current, etc)

Fully reprocessed when in-flight calibration available

urn:esa:psa:em16_tgo_nmd:data_partially_processed

Calibrated Data

Calibrated data with supporting geometry (Level 1.0)

Fully reprocessed when updated in-flight calibration available

SO, LNO and UVIS (solar occultation mode): pixel_wavenumber/wavelength, transmittance

LNO, UVIS (nadir mode): pixel-wavenumber/wavelength + radiance

urn:esa:psa:em16_tgo_nmd:data_calibrated

Derived Data

Retrieved atmospheric profiles/columns with supporting geometry (Level 2.0)

Global atmospheric fields from GCM (Level 3.0)

N/A

  • Neefs E., et al. (2015), NOMAD spectrometers on the ExoMars Trace Gas Orbiter Mission: part 1 - design, manufacturing and testing of the infrared channels. Applied Optics. Vol. 54, Issue 28, pp. 8494-8520. https://doi.org/10.1364/AO.54.008494

    Patel, M. R., et al. (2017), NOMAD spectrometers on the ExoMars Trace Gas Orbiter Mission: part 2 – the UVIS channel. Applied Optics. Vol. 56, Issue 10, pp. 2771-2782. •https://doi.org/10.1364/AO.56.002771