The COronal Diagnostic EXperiment (CODEX) is an International Space Station (ISS) mission that will deliver a next generation coronagraph to fill a critical gap in existing space weather measurements. By combining simultaneous electron density, temperature, and velocity, CODEX will enhance existing data from current missions such as Parker Solar Probe and stimulate advances in scientific modeling capabilities to improve understanding of the heliosphere.

CODEX is developed by NASA’s Goddard Space Flight Center (GSFC) and the Korea Astronomy and Space Science Institute (KASI). This imaging coronagraph observes polarized brightness images using 10 nm bandpass filters at 393.5, 405.0, 398.7 and 423.4 nm, and a broadband filter (380-430 nm). This will be the first time all three have been measured simultaneously for its 2.5 – 10 R_sun field-of-view (FOV), and CODEX makes these measurements globally for at least full six months, with 2 years extended mission possibility. Density measurement will be able to be obtained for each image of less than 1 minute exposure with 30 arcsec superpixel resolution. Temperature and velocity measurement will be able to be obtained by combining images for ~40 minute daytime of each orbit, with 4×4 (temperature) and 4.5×20 (velocity) sq-arcmin spatially binned resolution respectively.

GSFC provides instrument management and instrument system engineering, develops the mechanical structure, pointing system, thermal system, power distribution, ground systems, optical system, leads contamination control implementation, instrument I&T, calibration, data analysis, and sub-award institution management. KASI provides the fully-qualified C&DH computer and flight software, filter wheel, and detector subsystems. Instrument system-level integration and qualification is performed at GSFC. Integrated coronagraph is calibrated at Naval Research Laboratory (NRL). Pointing system is developed and tested at Wallops Flight Facility (WFF), and integrated with the coronagraph at GSFC. Integrated CODEX is shipped to Kennedy Space Center (KSC) and integrated with the launch vehicle. CODEX will be mounted to the zenith-side ExpRESS Logistics Carrier (ELC)-3 on the P3 (port) truss. It will be installed onto site 3, where an ISS-supplied FRAM will provide all electrical and mechanical interfaces to the ISS. Mounting of the coronagraph within the CODEX pointing system will provide solar pointing for science measurements. The ground portion of CODEX is divided into 2 segments. The Payload Operations Integration Center (POIC) located at Marshall Space Flight Center (MSFC) is the command and telemetry link from the ground to the payload. In addition, the Science and Operations Data Center (SODC) located at GSFC is the mission operations center. It is responsible for payload monitoring, commanding, and data handling (distribution, storage, processing). The operations team is led by GSFC. The GSFC team works with partners from KASI to carry out all collaborative tasks. GSFC and KASI share responsibility for the scientific analysis.