Rpws

Measurement of electric and magnetic fields, and electron density and temperature in the interplanetary medium and within Saturn's magnetosphere

The EUV and FUV channels are of similar construction and use a grating to form a spectrum on to a 60 x 1,024 array of detecting elements with the 1,024 element dimension in the spectral direction. The EUV records from 55.8 nm to 118 nm, and the FUV from 110 nm to 190 nm. In addition, the FOV has three settings for each spectrograph: (1, 2, 6) x 64mrad for the EUV and (0.75, 1.5, 6) x 64mrad for the FUV. UVIS is different from previous UV spectrometers in that rather than recording a spectrum from a single location, it records a series of spectra from 60 pixels across a field of view of length 64mrad. Hence, by scanning the instrument in the dispersion direction, multispectral images may be rapidly constructed. The width of individual pixels' FOV is adjustable, but is of the order of 1 mrad.

The photometer channel is a wideband channel recording between 115 nm and 185nm with a FOV of 6 x 6mrad and an integration time of 2ms. It is designed to perform stellar occultation measurements of Saturn's atmosphere and ring system. The hydrogen-deuterium absorption channel may also view the Saturnian system through onboard hydrogen, deuterium, and oxygen gas absorption cells to measure the abundances of hydrogen and deuterium.

The atmospheric science goals of the instrument are: (1) to map the vertical and horizontal composition of Saturn's and Titan's upper atmospheres and thus inves-

Table 7.7. Cassini orbiter remote-sensing instruments.

Instrument

Acronym

Purpose

Cassini Radar

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