Astrid-2, an advanced microsatellite for auroral research

The successful launch of the Swedish microsatellite Astrid-2 in December 19 98 began a new era of auroral research, with advanced microprobes of 30 kg or less used as research tools. Innovative technologies and low-mass soluti ons were used for the sensors and deployment systems to allow a fairly comp lete set of scientific instruments within the 10 kg allocated for the scien tific payload. A newly developed wire boom deployment system proved to func tion excellently. During its seven month lifetime Astrid-2 collected more t han 26 Gbytes of high-quality data of auroral electric and magnetic fields, and auroral particle and plasma characteristics from approximately 3000 or bits at an inclination of 83 degrees and an altitude of about 1000 km. Scie ntific results cover a broad range of topics, from the physics of energizat ion of auroral particles to how the magnetosphere responds to the energy in put from the solar wind and global magnetic field modelling. The fulfilment of both the technological and the scientific mission objectives has opened entirely new possibilities to carry out low-budget multipoint measurements in near-Earth space.