ARGUS Stereo-Spectral Imaging System

Main Objectives

    Study of the Martian surface and atmosphere

    Cartographic support of other experiments and next missions

ARGUS consists of three main scientific instruments:
    HRSC, a multifunctional high-resolution stereoscopic TV-camera for 0.1-1.0 µ m range;
    WAOSS a wide-angle stereoscopic TV-camera for 0.,1-0.7 µ m range;
    OMEGA, a mapping spectrometer for 0.35-5.2 µ m range.

All these instruments are arranged on a three-axis two-loop platform intended for pointing and stabilizing optical instruments with an accuracy of 4 sec of arc. The ARGUS independence is provided by its own multiprocessor control system and navigation TV camera (NC). its data acquisition system built around a 1 Gbit mass memory, its own thermal control system and in-flight calibration system.

    HRSC Multifunctional High Resolution Stereoscopic TV-Camera

Main Scientific Objectives

    Detailed topographic survey

    Multiband imaging and photometric studies of the surface with 3D reconstruction of its relief

    Atmospheric studies: cloud structures, limb brightness, terminator features

Instrument Description

    Multifunctional high-resolution stereoscopic TV camera built around 9 CCD arrays.

Main Performance Characteristics

     Focal length (mm)				175
     Angular resolution (sec of arc/pxl)	  8
     Spatial resolution (m) from H=300 km	 12
     Radiometric resolution (bit)		  8
     Spectral range (µ m)		    0.1-1.0
     Number of pixels per scanline	       5184
     Angle of view (degrees)		       11.5
     Swath width (km) from H=300 km		 62
     Convergence angle (degrees)		 20
     Mass (kg)					 24

    WAOSS: Wide-Angle Stereoscopic TV-Camera

Main Scientific Objectives

    Synoptic survey of Mars

    Global monitoring of time variations of the surface and atmosphere, in particular, cloud movements, changes due to dust storms, etc.

Instrument Description

    Synoptical wide-angle stereoscopic TV-camera built around 3 CCD arrays

Main Performance Characteristics

     Focal length (mm)				21.7
     Angular resolution (sec of arc/pxl)	  64
     Spatial resolution (m) from H=300 km	  96
     Radiometric resolution (bit)		   8
     Spectral range (µ m)		     0.4-0.7
     Number of pixels per scanline		5184
     Angle of view (degrees)			  80
     Swath width (km) from H=300 km		 496
     Convergence angle (degrees)		  20
     Mass (kg)					 7.1

OMEGA - Visible And Infrared Mapping Spectrometer

Main Scientific Objectives

    Mapping of the Martian surface composition: igneous and sedimentary rocks and soils, frosts and ices

    Mapping of major gaseous and solid atmospheric components

Spectral Channels

	IR-I (a range of 2.7-5.2 µ m)
	IR-2 (a range of 1.05-2.7 µ m)
	VNIR (a range of 0.35-1.05 µ m)

	Spectral resolution		50 to 100
	Angular resolution		4 min. of arc
	Spatial resolution		0.4 to 4 km
	Swath width			8.8° 
	Mass				29.1 kg

PFS - Planetary Fourier Spectrometer

Main Atmospheric Science Objectives

    Monitoring of 3D temperature and pressure fields
    Global mapping of winds
    Studies of variations of H2O and CO in space and time
    Aerosols: optical depth, phase function, size distribution and chemical composition

Main Surface Science Objectives

    Temperature and thermophysical properties of soils
    Mineralogical composition of the surface
    Surface condensates


    A two-channel Fourier-spectrometer

Main Performance Characteristics

	Channels				 LW	     SW

	Spectral range (µ m)			6-45	   1.25-4.5
	Spectral resolution (cm-2)		 2.3	     2.3
	Angular resolution (degree)		  4	     2.6
	Spatial resolution (km) from H=300 km	 20	      15
	Mass					     35.5 kg

TERMOSCAN - Mapping Radiometer

Main Scientific Objectives

    Thermal inertia of the Martian soil;
    Diurnal and seasonal dynamics of the temperature regime;
    Searching for anomalous heat sources;
    Thermal studies of the atmosphere.

Main Characteristics

	Spectral ranges				0.5-1.0 µ m, 8.0-13 µ m
	Instantaneous field of view:		1'
	Scanning angle				6° 
	Scan rate				1 line/sec
	Surface spatial resolution		0.1-1 km/pixe
	Temperature sensitivity			0.5° K at T = 240° K
	Mass 					28 kg

SVET - High-Resolution Mapping Spectrophotometer

Main Scientific Objectives

    Spectrophotometry of the planet in absorption bands of some rocks that may exist on the Martian surface in order to determine the surface composition;

    Study of the nature of aerosols by measuring spectral and angular distributions of brightness both above the planetary limb and of certain cloud-covered areas;

    TERMOSCAN-2 data conversion into digital form compatible with that of the MORION system.


    15 spectral subbands within 260-900 nm (a detector: two As-Ga arrays) and 5 subbands in the near-infrared

    Maps the surface in 32 lines with the mean resolution (about 1 km at the pericenter) in 8 high-resolution lines (300 m) and 1 low-resolution IR line (3 km)

    Pointing mirror permits observations of different areas of the planet

    Tracks pass over the planet surface in approximately meridional direction

Main Characteristics

	spectral range		260-900 nm and 1.05-27 µ m
	main detector array	As-Ga. 32 and 8 pixels
	main field of view	32 X (10' X 10')
	viewing range		-X -10° , +65° 
	mass				10 kg
	power consumption		9 W

SPICAM - Multichannel Optical Spectrometer

Main Scientific Objectives

    Vertical concentration profiles of ozone, water vapor, carbon monoxide, oxygen, dust, and temperature in the middle and lower atmosphere;

    Airglow spectroscopy to study the structure of the upper atmosphere;

    Global distribution of water vapor.


    Measurements of spectra of solar or stellar radiation, passing through the Martian atmosphere;

    Measurements of airglow spectra.



      Solar part of the instrument is a two-channel solar spectrometer installed on the orbiter body:

        UV and visible channel, lambda = 200 to 800 nm, lambda/delta-lambda = 1000
        IR channel, lambda = 1.8 to 5 µ m, lambda/delta-lambda = 1000


      Stellar part of the instrument installed on the PAIS platform

        a stellar spectrometer, lambda = 110 to 400 nm, lambda/delta-lambda = 300
        H2O band spectrometer, lambda = 936 nm, lambda/delta-lambda = 10,000

      Mass = 48.1 kg

UVS-M - Ultraviolet Spectrophotometer

Main Scientific Objectives

    Measure hydrogen, helium and oxygen distributions in the upper atmosphere of Mars
    Determine deuterium abundance in the Martian atmosphere
    Observe high-altitude temperature profile of the atmosphere
    Observe the neutral component of the interstellar-interplanetary medium.


    Photometer measures the intensity in lines:

      HI 1215.7 Å (neutral atomic hydrogen)
      DI 1215,3 Å (neutral atomic deuterium)
      Hel 584 Å (neutral atomic helium)
      0I 1304 Å (neutral atomic oxygen)
      0II 834 Å (singly-ionized atomic oxygen)

Main Characteristics

	power consumption		10 W
	data rate			137 bit/s
	mass				9.5 kg

LWR - Long-Wave Radar (GRUNT and PLASMA experiments)

Main Scientific Objectives


      Study of the underlying surface structure of the Martian cryolithospheres, the determination of the depth of occurrence of ice-bearing rocks and their geographic distribution, the estimation of dielectric parameters of soil.


      Measure global distribution of height profiles of electron number-density in the Martian upper ionosphere to study the dynamics of the solar wind interaction with the Martian upper atmosphere.

Method of Measurements

    Based on generating pulsed (with a linear modulation frequency) radio signals, measuring the power of signals reflected from the Surface at the night side of the planet, to determine the reflection coefficient within a wide spectral range. This method also uses measurements of time delay for signals reflected from the ionosphere at different heights in order to obtain electron number-density profiles.

Main Characteristics

	Frequency range				0.17-5 MHz
	Number of discrete frequencies		56
	Frequency modulation period		0.27 s, 1.08 s
	Frequency deviation			15 kHz
	Range measurement error			3.5 km
	Sounding range

during soil Sounding 150-3000 km during ionogram recording 150-5000 km Total mass 30.5 kg

PHOTON - Gamma-ray Spectrometer

Main Scientific Objectives

    Geochemical mapping of the elemental composition of Martian surface rocks with high spatial resolution and high accuracy;

    Determination of the abundance of natural radioactive elements (K,U,Th), basic rock-forming elements and minor elements (H, C, Mg, Al, Si, S, Cl, Ca, Ti, Fe)

Method of Measurements

    Based on recording gamma-rays from natural radionuclides in rocks and gamma rays generated by nuclear interactions of cosmic rays with elements of Martian surface rocks.


    Detection unit (BD-1) using a CsI crystal, with a bismuth germanate co!limator, installed on PAIS platform. The collimator provides high spatial resolution measurements of element abundance

    Omnidirectional detection unit (BD-2) with a large CsI crystal (785 cm3). It is placed on a solar panel. The use of a large volume crystal permits the abundance of rock-forming elements to be determined with a high accuracy; amplitude analyzer of counts with 4096 channels. It records gamma spectra from BD-1 and BD-2 units as well as spectra from the PGS detection unit with a superpure germanlure crystal.

Main Characteristics:

	parameter to be measured	energy spectrum of gamma-rays
	energy range			0.2 to 10 MeV
	energy resolution at
		Ev 0.661 MeV:		7.5%
	data capacity			3 Mbit/revolution
	mass				20 kg

NEUTRON-S - Neutron Spectrometer

Main Scientific Objectives:

    Determine water content in the surface layer of Martian soils.


    Measures the flux intensity of neutrons generated in nuclear reactions caused by the interaction of galactic and solar cosmic rays with surface regolith.

    The instrument consists of two units of detectors with six neutron counters, and an electronics unit. Neutron counters are built around 3He, the reaction 3He (n,p) 3H + 0.768 MeV is used. The working pressure in the counters is about 7 atm.

Main Characteristics

	Energy range				0.01 < E < 0.4  eV
						1 < E < 2 keV
						0.01 < E < 3 MeV
	Measurement time			102-103 s
	Angle of view				45°
	Minimum detectable water content	0.5 weight %
	Mass					10 kg
    It is possible to detect hydrogen in the rock covered by a dry regolith layer up to 100 g/cm2 thick and to measure the ice thickness up to 250 g/cm2 in the polar cap.

MAK - Quadrupole Mass Spectrometer

Main Scientific Objectives

    Composition of the Martian upper atmosphere and ionosphere
    Measurement of height profiles of the atmospheric ion and neutral composition
    Measurement of H+ D+ He+ abundances and the H+/D+ isotope ratio
    Measurement and updating of the isotope ratios O17/O18, Ne20/Ne22, Ne20/Ne21, Ar36/Ar38
    Measurement of seasonal and diurnal variations of the Martian upper atmosphere and ionosphere


    Quadrupole mass-spectrometer which operates in ion and neutral atom recording modes.

Main Characteristics

						 mode 1		mode 2
	atomic mass range		       1-6 a.m.u.     1-60 a.m.u.
	dynamic range
	sensitivity nmin (cm3)
		for ions			  10-3		10-5
		for neutrals					104
		for neutrals H2 and H				106
	time needed to measure one spectrum			10 s
	mass							12 kg

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