HELIX EMPLOYS A HIGH-PRECISION MAGNET SPECTROMETER TO PROVIDE MEASUREMENTS WHICH ARE NOT ACHIEVABLE BY ANY CURRENT OR PROPOSED INSTRUMENT. THE DETECTOR SYSTEM WILL INCORPORATE THE EXISTING SUPERCONDUCTING MAGNET CONSTRUCTED FOR THE HEAT PAYLOAD WHICH HAS SUCCESSFULLY OPERATED ON FIVE PREVIOUS HIGH-ALTITUDE CAMPAIGNS. THIS MAGNET WILL BE COMBINED WITH STATE-OF-THE-ART DETECTORS TO MEASURE THE CHARGE TIME-OF-FLIGHT MAGNETIC RIGIDITY AND VELOCITY OF COSMIC-RAY PARTICLES WITH HIGH PRECISION. SPECIFICALLY THEINSTRUMENT WILL COMBINE PLASTIC SCINTILLATORS A SILICON-STRIP TRACKER WITH ~30 MICRON SPATIAL RESOLUTION A HIGH-PERFORMANCE DRIFT CHAMBER AND A RING-IMAGING CHERENKOV COUNTER EMPLOYING AEROGEL RADIATORS. THE INSTITUTION WILL BE RESPONSIBLE FOR FABRICATING THE BOTTOM TIME OF FLIGHT DETECTORS INSTRUMENT RECOVERY PREPARATIONS AND SHARE SIMULATIONS AND ANALYSIS WITH ALL.