LINDA - the Astrid-2 Langmuir probe instrument

The Swedish micro-satellite Astrid-2, designed for studies in magnetosperic physics, was launched into orbit on 10 December 1998 from the Russian cosm odrome Plesetsk. It was injected into a circular orbit at 1000 km and at 83 degrees inclination. The satellite carried, among other instruments, a dou ble Langmuir Probe instrument called LINDA (Langmuir INterferometer and Den sity instrument for Astrid-2). The scientific goals of this instrument, as well as the technical design and possible modes of operation, are described . LINDA consists of two lightweight deployable boom systems, each carrying a small spherical probe. With these probes, separated by 2.9 meters, and in combination with a high sampling rate, it was possible to discriminate tem poral structures (waves) from spatial structures. An onboard memory made it possible to collect data also at times when there was no ground contact. P lasma density and electron temperature data from all magnetic latitudes and for all seasons have been collected.