IASI, the Infrared Atmospheric Sounding Interferometer, was launched on METOP, a European meteorological polar-orbiting satellite, in October 2006. (Delayed from April 2006). Funded by EUMETSAT, the Joint Airborne IASI Validation Experiment (JAIVEX) used the FAAM BAe146 aircraft in validation studies of IASI radiative transfer and some level 2 products.