Roman Coronagraph Data Format and Access

The primary astronomical observation data from the Coronagraph instrument will be taken with its EXoplanetary systems Camera (EXCAM). The coronagraph data levels are defined from Level 0 to 4. The Coronagraph Data Management System (CDMS) processes raw packetized telemetry files (Level 0) data to Level 1. These data are stored in the Data Analysis Environment (DAE) for the Coronagraph Technology Center (CTC) and Community Participation Program (CPP) to process to Level 2, 3, and 4. The data levels are defined below:

  • Level 0: All raw, packetized telemetry from the instrument
  • Level 1: Raw, uncalibrated image arrays, with metadata headers
  • Level 2: First stage detector-calibrations applied (bias & nonlinearity corrected)
  • Level 2b: Photon counting applied if applicable, additional detector calibrations (dark, flat, smearing)

  • Level 3: Normalized by exposure time, WCS solutions for imaging, wavelength corrected where applicable, and polarization cubes where applicable

  • Level 4: Distortion corrected, aligned and combined, PSF-subtracted if applicable





Ancillary Technology Demonstration Data Products and Calibration Reference Files

In general, all raw coronagraph telemetry necessary for data reduction will be processed to a machine or human-readable format by the SSC. All official data products will be validated by the CDMS and sent to the SOC for archiving. Much ancillary (non-image) coronagraph telemetry will be included in the L1 image data headers. Some ancillary data will be further processed by the CTC and CPP. The ancillary data and telemetry include:

  • Data from mechanisms and camera settings 
  • Status from each wavefront control system at the time of the observation 
  • Calibrations generated autonomously on board 
  • Subset of housekeeping data on the science recorder 
  • Low-order Camera (LOCAM) images

Calibration reference files will also be generated from observational and/or modelling data by the CTC. These files may include, but are not limited to:

  • Flat fields
  • Darks
  • Bad pixel maps
  • Astrometric calibration files (including pixel scale solution, distortion correction, satellite spot calibration, etc.)
  • Photometric calibration files (including flux conversion file, etc.)
  • Instrumental polarization calibration files

A limited set of calibration files generated on the ground will be sent up to the spacecraft for use during coronagraph observations. The data are created by the CTC and uploaded by the MOC. Currently, the flat fields are the only image files anticipated to be needed for onboard calibration.

Data Volume

The peak coronagraph data rate spacecraft allocation is 60 Mbps, with a current best estimate (CBE) of 4.6 Mbps. Over a 24 hr period, the CBE Coronagraph data volume is about 0.430 Tb, with a spacecraft allocation of 3 Tb for Level 0 data. The Level 1 to Level 4 data volume for an average observation is expected to be at least 2.6 Tb. For the full technological demonstration, the expected data volume will be at least 34 Tb.


Data Analysis Environment

The SSC will operate and maintain a Data Analysis Environment (DAE) combining processing resources and disk space, to support the data processing needs of the CGI technology demonstration, including HOWFSC/GITL and the L2-L4 data processing of the CTC and CPP. The DAE will support compliant software developed by the CGI team at JPL, CTC, or Community Participation Program teams. Access to the DAE will primarily be remotely with a designated user interface. 

Data Access

All Roman science data will immediately be publicly available and there will be no exclusive access period. Users will be able to access Roman data through the Roman Research Nexus (RRN) and the Barbara A. Mikulski Archive for Space Telescopes (MAST).



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