Prelaunch Characterization Data

Prelaunch Characterization Data

The PACE Mission will carry three instruments: Ocean Color Instrument (OCI), Spectro-polarimeter for Planetary Exploration one (SPEXone), and Hyper-Angular Rainbow Polarimeter 2 (HARP2). The latest information on radiometric/polariometric characterization and performance, including relative spectral response (RSR) and signal to noise (SNR) is provided here for each sensor.


The OCI instrument is highly configurable with respect to spectral sampling across the hyperspectral focal planes. The initial on-orbit configuration will be the so-called ‘baseline mode’, providing 119 spectral bands on the blue FPA, and 163 spectral bands on the red FPA. Note that the wavelength range above 600 nm for the blue FPA is replicated on the red FPA, but the red FPA provides higher radiometric accuracy in that spectral range. The initial on-orbit RSR are provided in version 1.1.1. They were derived from flight unit testing and are based on RSR measurements sampled at 1nm for most wavelengths and 0.1nm at selected wavelengths). In-band RSR below 900nm without 0.1nm coverage were modelled combining all available measurements, including component level optical throughput measurements. The results were interpolated to a common 0.1nm wavelength grid and are provided here for the OCI L1B bands in baseline mode:

OCI has two bands (1250nm and 1615nm) that are provided in both standard gain and high gain. Standard gain is provided before high gain in the RSR table. Note that occasional negative RSR values can be due to either measurement noise (typically less than 1e-6) or electronic crosstalk. The center wavelengths and bandwidths are provided in the above netcdf file as well. They are also provided in an ASCII file:

A simulated version of the OCI spectral response, based on information gained from the OCI Engineering Test Unit (ETU) and coupled with additional assumptions and modeling, is available below. This version was used for producing simulated Level-1B OCI data through PyTOAST (V9).