The FORTÉ project is sponsored by the Department of Energy and is an experiment to examine technologies for possible use as part of the U.S. nuclear detection system. This system supports efforts to curb the proliferation of nuclear weapons around the globe.
FORTE is the first all-composite spacecraft, its framework made entirely of graphite-reinforced epoxy. The seven-foot-tall satellite, weighing 470 pounds fully loaded, carries three decks with aluminum honeycomb cores and composite facing to support the onboard instruments.The FORTÉ payload consists of three instruments: an RF system, an optical system, and an "event classifier". The RF system incorporates three broad bandwidth RF receivers covering the frequency range 30-300 MHz, a polarization-selective antenna, and high speed waveform digitizers. The optical system consists of a coarse imager which is based on a NASA/MSFC design and has a 10km X 10km ground resolution for lightning flash location (500 frames/sec) and a fast photodetector (50k samples/sec) for recording individual light curves. The event classifier, based on digital signal processing technology, will provide on-orbit characterization of impulsive RF events which have satisfied trigger criteria.
FORTE includes a radio frequency sensor system with three broad-bandwidth receivers covering the range of 30-300 Megahertz, which includes commercial and UHF television, amateur and FM radio and aircraft navigation and communication bands. The improved detection technology that is undergoing testing on FORTE is the first step; scientists eventually hope to develop and launch an autonomous radio frequency detection system that performs reliably in the electromagnetically noisy environment of near-Earth space. FORTE receives radio frequency signals via a novel, 35-foot-long antenna that has two arrays set at right angles to each other to help researchers learn how the ionosphere affects the propagation of radio frequency signals.
The satellite also carries a Sandia-designed wide-field optical imager that can locate lighting flashes and pinpoint global lightning distribution to a six-mile resolution. The third major instrument on FORTE is an event classifier, a set of adaptive processors that can distinguish lightning from man-made electromagnetic signals, a key to future nonproliferation satellites.
