We have developed a new high-energy particle spectrometer, called the Light Particle Detector (LPD), that discriminates and energy analyzes protons, electrons and heavy ions over a wide energy range. The LPD sensor supports the Space Environment Reliability Verification Integrated System (SERVIS) mission of the Japanese Institute for Unmanned Space Experiment Free Flyer (USEF). The LPD design focuses on those aspects of the environment most damaging to spacecraft systems. LPD has good performance for high-energy protons and ions responsible for single event effects. It also has good performance of the low energy protons that cause material damage. In addition, LPD has good efficiency for low energy electronics responsible for deep dielectric charging as well as the higher energy "killer electrons". The LPD design is based on a single SSD and a small inorganic crystal scintillator. This fully redundant sensor uses state-of-the art electronics to process each incident particle into a compact spectral distribution. The energy ranges are: protons 1 to 150 MeV; electrons 0.3 to 20 MeV, ions 2 to 160 MeV/ nucleon. The sensor also has a large G-factor (0.2 cm² sr) and a high count rate (>200 kcps). We present the sensor designs as well as calibration results and Monte Carlo sensor performance predictions.