Instruments
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HITS
ISAAC
LORAAS

Mechanical drawing of the HIRAAS instrument package.HIRAAS is located on the nadir panel of ARGOS.

Instrumentation

The HIRAAS experiment package consists of 3 ultraviolet (UV) spectrographs collectively spanning the middle-, far-, and extreme-ultraviolet (MUV,FUV,EUV) passbands.  These sensors use diffraction gratings to disperse UV radiation into its component wavelengths, and then measure the intensity of each emission component with sensitive UV detectors.  Limb profiles are accumulated by scanning the fields-of-view of the sensors.

Length: 1.37 m (54 inches)
Width:  0.61 m (24 inches)
Height: 0.55 m (22 inches)
Mass: 120 kg (265 lbs)
Power: 136 Watts

Location of HITS instrument highlighted.    HITS

The High resolution Ionospheric and Thermospheric Spectrograph (HITS) is a 1-m Rowland circle spectrograph covering the EUV/FUV (50-180 nm) passband with better than 0.1 nm spectral resolution.  HITS uses a wedge-and-strip microchannel plate detector with a CsI photocathode.  Limb scanning is performed by gimballing the entire HITS spectrograph.

Location of ISAAC instrument highlighted.    ISAAC

The Ionospheric Spectroscopy and Atmospheric Chemistry (ISAAC) spectrograph is a 0.125-m Ebert-Fastie spectrograph covering the MUV (180-320 nm) passband with 0.4 nm spectral resolution.  ISAAC uses a Hammamatsu diode array detector with an image intensifier.  ISAAC is attached to the HITS platform which scans the limb.

Location of LORAAS highlighted.    LORAAS
 
The Low Resolution Atmospheric and Auroral Spectrograph (LORAAS) is a 0.25-m Wadsworth-type spectrograph covering the EUV/FUV (80-175 nm) passband with 1.8 nm spectral resolution.    LORAAS uses a wedge-and-strip microchannel plate detector with a partial CsI photocathode.  Limb scanning is performed with an internal objective mirror.