October 10, 2014

Spicav

(SPectroscopy for the Investigation of the Characteristics of the Atmosphere of Venus)

SPICAV is a spectrometer with 3 channels:


SPICAV sensor set
(IR and UV channels)

SOIR is mounted above
SPICAV’s UV and IR channels

  • SPICAV-UV: a UV spectrometer (118-320 nm) for nadir or limb aiming and determining the atmosphere’s vertical profile using solar and stellar occultation. This channel could quantify CO2, SO2, and aerosol presence. It also helped study the ionosphere and the atmosphere’s vertical temperature profile.
  • SPICAV-IR: an IR spectrometer (0.7-1.7 µm) for nadir sounding and H20 solar-occultation.
  • SOIR (Solar Occultation and Infrared): this additional channel was added on Venus-Express to observe the Sun through the Venusian atmosphere in infrared wavelengths.
  • DPU (Data Processing Unit): this electronic unit was able to interface the satellite with the 3 channels.

SPICAV had a dedicated entrance aperture for solar occultation, separate from the one used in nadir aiming and stellar occultation.

The instrument was developed in a partnership involving 3 institutes:

  • LATMOS (France) was the prime contractor on the instrument.
  • BIRA-IASB (Royal Belgian Institute for Space Aeronomy) was in charge of manufacturing the mechanical elements and providing the SOIR channel.
  • IKI (Russian Space Research Institute) developed the IR spectrometer.

The following tables present the main specifications for the UV and IR channels:

TelescopeOff-axis parabolic mirror
Field of view1 ° x 3.16 °
SpectrometerHolographic diffraction grating
DetectorCCD Thomson TH 7863 (384x288 pixels)
+ Hamamatsu intensifier
Detector dimensions8.8 x 6.6 mm
Pixel size23 x 23 µm
Range118 - 320 nm
Spectral resolution1.5 nm
Main specifications for SPICAV’s UV channel
 
TelescopeCollimator lens
Instantaneous field of view1 °
SpectrometerAOTF (Acousto Optic Tunable Filter)
DetectorHamamatsu InGaAs photodiode
Detector dimensions1 mm²
Pixel size1 mm²
Range0.7 - 1.7 µm
Spectral resolution1 nm
Main specifications for SPICAV’s IR channel

The following table presents SPICAV’s general specifications:

Flight model data
MassUV + IR channels4.14 kg
DPU0.711 kg
SOIR channel7 kg
Total13.195 kg
PowerDPU2 W
IR channel8 W
UV channel15 W
SOIR channel30 W
Telemetry
(1 orbit)
Typically
100 to 400 Mb/day
SPICAV characteristics