Janet G. Luhmann (born 1946) is an American physicist and senior fellow of the Space Sciences Laboratory of the University of California, Berkeley. She has made major contributions to a wide range of topics in planetary, solar, magnetospheric, and heliospheric physics. She is the principal investigator of the IMPACT instrument suite on the twin-spacecraft STEREO mission. IMPACT stands for In-situ Measurements of Particles and Coronal mass ejection (CME) Transients. It consists of a, "suite of seven instruments that samples the 3-D distribution of solar wind plasma electrons, the characteristics of the solar energetic particle (SEP) ions and electrons, and the local vector magnetic field." Source: Wikipedia (en)