The major telescopes on board the SPECTRUM-X-GAMMA satellite are two SODART X-ray telescopes with 8 m focal lengths. One of them includes the Finnish experiment SIXA (Silicon X-ray Array detector) as one of its focal plane instruments. SIXA's main task will be the measurement of X-ray spectra with good resolution. The SIXA detector capsule consists of 19 discrete, circular, and closely packed lithium drifted silicon detector elements. A passive cooling system on the satellite provides 110 - 120 K operating temperature for the detector. Special attention has been paid to reducing detector leakage currents in order to achieve the desired resolution of 170 - 180 eV at 6 keV for 50 mm2 active area detector elements within the temperature range of the cooler. In a parallel study, fabrication of 19 separate measuring pixels on a single lithium drifted silicon wafer is being investigated. The analog electronics section consists of 19 parallel amplifier channels. Two microprocessors are used to provide up to four simultaneous measurement modes for different scientific purposes. Use of hard disk drives in hermetically sealed containers as mass memory is under study. This paper gives an updated description of the SIXA spectrometer concept.