The EXoplanet Climate Infrared TElescope (EXCITE)*

The EXoplanet Climate Infrared TElescope (EXCITE) is a stratospheric balloon-borne instrument with a 0.5-meter primary mirror designed to perform phase-resolved spectroscopy of hot Jupiter atmospheres in the 0.8 – 4 um range. EXCITE will observe targets through the peak of their spectral energy distribution and through spectral signatures of hydrogen and carbon-containing molecules. EXCITE will fly from a long-duration balloon platform and provide critical insights into atmospheric composition, vertical thermal structure, and longitudinal brightness maps. EXCITE leverages a pointing system design which has achieved milliarcsecond stabilization and will continuously observe exoplanets throughout entire orbits.

This presentation outlines EXCITE scientific objectives and provides an overview of the critical subsystems with a focus on the cryogenic receiver and the cryogenic control electronics. We detail its operational requirements, review its performance during a 2024 engineering flight from Fort Sumner, New Mexico, and discuss the preparation of future long-duration science flight from McMurdo station, Antarctica.