The Crosstrack Infrared Sensor (CrIS) is an IR Michelson type medium-resolution Fourier Transform Spectrometer (FTS). It was launched into orbit in the fall of 2011 onboard the NPOESS Preparatory Platform (NPP) satellite. Firstlight CrIS observations received in early January 2012 were processed by the CrIS Sensor Data Record (SDR) algorithm that transforms the digitized interferograms into radiometrically and spectrally calibrated Earth scene spectra. At this time, the CrIS SDR algorithm uses the pre-launch calibration coefficients derived from the thermo-vacuum testing. Preliminary assessment of the algorithm and early results are presented here. On-going intensive calibration/validation activities will give an updated set of calibration coefficients. The CrIS SDR radiance products (spectra) are essential for assimilation into the NWP weather forecasting system.