Abstract: Detailed mapping of the magnetosphere is made possible by deploying hundreds of attitude-impervious microsatellites, in the form of small corner reflectors with piezoelectric mirror surfaces, from a single mother satellite at spacings of as little as 1 km in equatorial and elliptical orbits. The microsatellites carry magnetosensors whose output is transmitted to a ground station by modulating the reflection of a laser beam transmitted to the microsatellite by the ground station. Various refinements of the laser data link are also disclosed.