GISMOS project consists of approximately 40 flight hours on the GV that are designated to testing the GNSS Instrument System for MultiStatic and Occultation Sensing, a HAIS instrument. GISMOS is a part of HEFT-08 project. The project will involve flights over the Gulf of Mexico at cruise altitude (approximately 42 kft), overflying several NOAA buoys. Another target for these flights are several radiosonde launches that the GV will overfly at certain times of the day. This activity will result in GV spending the night at a coastal location (possibly in FL, TBD). During these flights the priority for mission objectives will be given to GISMOS, all other objectives will be considered on a non-interference basis.