HaloSat: X-Ray Calibration and Spectral Analysis for a NASA CubeSat

HaloSat is a NASA funded 6U CubeSat designed to measure the mass of baryonic matter in the Milky Way's hot Galactic halo. Currently in low Earth orbit, HaloSat uses three X-ray silicon-drift detectors sensitive in the 0.4 - 2 keV band. HaloSat will map the geometry of the Galactic halo through detection of X-rays from O VII and O VIII at ~600 eV. We present on the laboratory measurements of the HaloSat flight detectors, including: alignment, energy calibration, and performance optimization. We show analysis of in-lab and initial on-orbit data.