The CCOR Compact Coronagraphs for the Geostationary Operational Environmental Satellite-19 (GOES-19) and the Space Weather Follow On (SWFO) Missions
A. F. Thernisien, D. H. Chua, M. T. Carter, N. B. Rich, M. Noya, T. A. Babich, C. E. Crippa, B. Baugh, Y. Bordlemay, D. Socker, D. Biesecker, C. Korendyke, D. Wang, D. Vassiliadis, N-Y. Wang, S. Abbay, S. Bagnall, L. Balmaceda, S. Brown, J. Bonafede, D. Boyer, J. Declet, P. Cheng, K. Corsi, L. Cremerius, I. Chavis, J. Chiralo, G. Clifford, J. Dancheck, J. Davis, G. Dima, R. Dudley, D. Gardner, L. Gardner, B. Hagood, R. Hagood, B. Hohl, T. Hunt, F. Jenkins, J. M. Johnson, M. Koehler, N. Kuroda, A. Lanagan, S. Laut, B. Lynch, T. Mallory, D. Mechel, N. D. Miles, A. Miranda, M. Newman, B. Nguyen, M. Ogindo, K. Pellak, R. Podgurski, T. Ragan, V. Richards, D. Silver, J. Simmons, D. J. Schmit, L. Smith, J. Spitzak, S. K. Tadikonda, S. Tanner, D. Uhl, J. Verzosa, P. Walker, G. Wiggins, E. Williams, C. Wilson, D. Zurcher
TL;DR
The paper presents the CCOR Compact Coronagraphs as two operational solar coronagraphs for NOAA’s SWPC, deployed on GOES-19 (CCOR-1) and SWFO-L1 (CCOR-2). It details a compact external-occulted optical design with no internal occulter, achieving LASCO-like performance in a half-length instrument, and emphasizes stray-light control, a 470–740 nm bandpass, and a 15-minute synoptic cadence with ground latency under 30 minutes. It covers driving science objectives, spacecraft accommodations, instrument design, ground processing, and data products, and demonstrates compliance with NOAA requirements for CME detection, speed and mass estimation, and near-real-time forecasting workflows. The work also outlines future CCOR iterations, including CCOR-3 on Vigil, enabling multi-point CME localization and improved space weather forecasting capabilities.
Abstract
The CCOR Compact Coronagraph is a series of two operational solar coronagraphs sponsored by the National Oceanic and Atmospheric Administration (NOAA). They were designed, built, and tested by the U.S. Naval Research Laboratory (NRL). The CCORs will be used by NOAA's Space Weather Prediction Center to detect and track Coronal Mass Ejections (CMEs) and predict the Space Weather. CCOR-1 is on board the Geostationary Operational Environmental Satellite -U (GOES-U, now GOES-19/GOES-East). GOES-U was launched from Kennedy Space Flight Center, Florida, on 25 June 2024. CCOR-2 is on board the Space Weather Follow On at Lagrange point 1 (SWFO-L1). SWFO-L1 is scheduled to launch in the fall of 2025. SWFO will be renamed SOLAR-1 once it reaches L1. The CCORs are white-light coronagraphs that have a field of view and performance similar to the SOHO LASCO C3 coronagraph. CCOR-1 FOV spans from 4 to 22 Rsun, while CCOR-2 spans from 3.5 to 26 Rsun. The spatial resolution is 39 arcsec for CCOR-1 and 65 arcsec for CCOR-2. They both operate in a band-pass of 470 - 740 nm. The synoptic cadence is 15 min and the latency from image capture to the forecaster on the ground is less than 30 min. Compared to past generation coronagraphs such as the Large Angle and Spectrometric Coronagraph (LASCO), CCOR uses a compact design; all the solar occultation is done with a single multi-disk external occulter. No internal occulter is used. This allowed a substantial reduction in size and mass compared to SECCHI COR-2, for example, but with slightly lower signal-to-noise ratio. In this article, we review the science that the CCORs will capitalize on for the purpose of operational space weather prediction. We give a description of the driving requirements and accommodations, and provide details on the instrument design. In the end, information on ground processing and data levels is provided.