This book includes the proceedings of the Workshop held in Madrid, April 1999 to celebrate 2 years of successful operation of the first Spanish small scientific satellite in orbit. It contains discussions about the overall philosophy of small mission programs, the design of the satellite and its payload as well as the most relevant scientific outcome of the mission. Also included are additional contributions to the workshop, which are of importance to Minisat 01 in order to put its results within context. Finally, the future of small missions for space sciences is reviewed together with the main technological challenges for new studies. Out of the technological and scientific results of Minisat 01, the measurement of the EUV airglow spectrum and the flux of some stars in the same range can be highlighted together with the dismiss of the massive neutrino decay theory. The high-energy experiment analyzed the characterization of the radiation environment in LEO and the behaviour of different kind of detectors, as well as the use of coded masks for imaging and the measurement of some specific sources. The book's level is intended for specialists in EUV and Hard X-Ray astrophysicists as well as for engineers and technicians involved in space science experiments and missions.Proceedings of the Workshop held in Madrid 26-28 April 1999Opening Keynote; 1. Spanish Minisat Program: Objectives And Operational Results; M.A. Garc?a Primo. 2. Minisat 01 as a Scientific Mission and its future; A. Gim?nez. 3. Development of Minisat 01 Scientific Payload; J. Torres and R. Alfageme. 4. Performances of Minisat 01 Platform Subsystems; F.C. Mart?nez. 5. SIXE: An X-Ray Experiment for the Minisat Platform; J. Isern, et al. 6. XRASE: The X-Ray Spectroscopic Explorer; H. Schnopper, et al. 7. X-Ray Binary Systems: A Cauldron of Physical Processes; F. Giovannelli and L. Sabau-Graziati. 8. Three lƒ&