Earth Planets Space, Vol. 52 (No. 1), pp. 49-60, 2000

Ultraviolet imaging spectrometer (UVS) experiment on board the NOZOMI spacecraft: Instrumentation and initial results

M. Taguchi¹, H. Fukunishi², S. Watanabe³, S. Okano¹, Y. Takahashi², and T. D. Kawahara⁴

¹National Institute of Polar Research, Tokyo 173-8515, Japan
²Department of Geophysics, Tohoku University, Sendai 980-8578, Japan
³Department of Earth and Planetary Science, Hokkaido University, Sapporo 060-0810, Japan 4Department of Information Engineering, Shinshu University, Nagano 380-0922, Japan

(Received March 18, 1999; Revised September 20, 1999; Accepted October 19, 1999)

Abstract: An ultraviolet imaging spectrometer (UVS) on board the PLANET-B (NOZOMI) spacecraft has been developed. The UVS instrument consists of a grating spectrometer (UVS-G), an absorption cell photometer (UVS-P) and an electronics unit (UVS-E). The UVS-G features a flat-field type spectrometer measuring emissions in the FUV and MUV range between 110 nm and 310 nm with a spectral resolution of 2-3 nm. The UVS-P is a photometer separately detecting hydrogen (H) and deuterium (D) Lyman aemissions by the absorption cell technique. They take images using the spin and orbital motion of the spacecraft. The major scientific objectives of the UVS experiment at Mars and the characteristics of the UVS are described. The MUV spectra of geocoronal and interplanetary Lyman aemissions and lunar images taken at wavelength of hydrogen Lyman a and the background at 170 nm are presented as representative examples of the UVS observations during the Earth orbiting phase and the Mars transfer phase.