The neutron star interior composition explorer (NICER): commissioning and calibration (Conference Presentation)

NASA's Neutron star Interior Composition Explorer (NICER) progressed smoothly through its final ground-test activities in 2016 and early 2017, in preparation for a spectacular launch and installation on the International Space Station in June 2017. Activation of the payload and initial calibration of its systems followed, rounding out Phase D, Testing and Commissioning, of the mission's development cycle. We describe the final ground verification measurements of NICER's key performance parameters, such as the X-ray Timing Instrument's photon energy resolution and time-stamping accuracy, as well as in-flight effective collecting area, pointing, background, and other calibration efforts. The payload meets all of its design requirements and is poised to deliver new insights in soft X-ray astrophysics; briefly, we touch on early science returns that showcase NICER's unique capabilities.