LEGRI SCIENCE OPERATION CENTER. ARCHITECTURE AND OPERATIONS PERE BLAY, JULIA SUSO, ALMUDENA ROBERT, JOSE LUIS REQUENA, JORGE ALAMO and VICTOR REGLERO GACE, Instituto de Ciencias de los Materiales, Universidad de Valencia, P.O. Box 2085, 46071 Valencia, Spain CHRIS J. EYLES University of Birmingham, Space Research Group, School of Physics and Astronomy, Birmingham B15 2TT, United Kingdom Abstract. The LEGRI Science Operation Center (SOC) is the single contact point between the MINISAT-01 Centro de Operaciones Científicas (COC) located at Villafranca del Castillo (Madrid) and the LEGRI Consortium. Its architecture, operational procedures and associated software has been developed at the Universities of Valencia and Birmingham on the scope to define a integrated Data Analysis System, able to perform the daily follow-up of the instrument health, raw data files decom- pression and archiving activities (on-line and historical). Pointing and telecommand files generation are also SOC responsibilities. The aim of this paper is to report the SOC activities during the two years of LEGRI operations. Conclusions about the SOC architecture and procedures evolution on how to handle the operations for space-borne instrumentation, are also presented. Special attention has been paid to the operative evaluation of the pointing reconstruction solutions from the MINISAT- 01 Attitude Control System by comparing them with those obtained with the LEGRI Star Sensor. The analysis of one year of observations shows the good agreement between both sets of data. No systematic deviations have been found with an averaged standard deviation of 1 degree in alpha and delta coordinates. For most of the time the MINISAT pointing system is working slightly better than expected and within specifications. 1. Introduction MINISAT-01 was launched on April 21st 1997 by a PEGASUS rocket in the Ca- nary Islands area. The MINISAT-01 is a scientific mission carrying a scientific payload composed of two astronomical instruments (LEGRI and EURD) and one experiment on microgavity (CPLM). The total mass is 200 Kg being 100 Kg for instrumentation. LEGRI is a prototype of a gamma ray imager based on the use of solid state detectors and a coded aperture system. Two different type of detectors have been implemented on LEGRI: 80 HgI2 and 20 CdZnTe. The LEGRI also includes an optical telescope developed by the Rutherford Appleton Laboratory (RAL) for pointing reconstruction purposes, the Star Sensor (SS). See Reglero et al. (1997) for further information. Astrophysics and Space Science is the original source of this article. Please cite this article as: Astrophysics and Space Science 276: 311–323, 2001. © 2001 Kluwer Academic Publishers. Printed in the Netherlands.