Energy Spectrum of Cosmic-Ray Electron and Positron from 10 GeV to 3 TeV Observed with the Calorimetric Electron Telescope on the International Space Station

First results of a cosmic-ray electron and positron spectrum from 10 GeV to 3 TeV is presented based upon observations with the CALET instrument on the International Space Station starting in October, 2015. Nearly a half million electron and positron events are included in the analysis. CALET is an all-calorimetric instrument with total vertical thickness of 30 X-0 and a fine imaging capability designed to achieve a large proton rejection and excellent energy resolution well into the TeVenergy region. The observed energy spectrum over 30 GeV can be fit with a single power law with a spectral index of -3.152 +/- 0.016 (stat + syst). Possible structure observed above 100 GeV requires further investigation with increased statistics and refined data analysis.