UC Berkeley engineers and managers watch as the COSI (Compton Spectrometer and Imager) detector assembly is slowly raised from a table in this July 8, 2026,

Engineers Bradley Pafchek and Matt Rubly examine the COSI (Compton Spectrometer and Imager) detector assembly at Space Sciences Laboratory on July 15, 2026. COSI is an upcoming spacecraft that will measure gamma rays, the highest-energy form of light, to help scientists study energetic phenomena in the Milky Way and beyond. Credit: UC Berkeley/Alan Toth Alt text: Two people examine the COSI detector assembly.Image description: Two people stand on yellow step ladders and lean over to examine a small gold box. The box is centered inside the top of a hexagonal white frame. A larger hexagonal silver and black box extends from the bottom of the frame. The person on the left wears a blue cleanroom suit, and the one on the left wears a white one. They both wear hairnets, masks, gloves, and shoe covers. A floor-to-ceiling plastic sheet separates the back of the room, which is full of metal shelving and boxes. || COSI_2026July_19_half_print.jpg (1024x682) [223.9 KB] || COSI_2026July_19.jpg (5000x3333) [4.6 MB] || COSI_2026July_19_half.jpg (2500x1667) [576.0 KB] ||

YouTube video by UC Berkeley Space Sciences Laboratory

Scientists study small galaxies to look for hints of dark matter in the universe.

COSI is an Astrophysics Small Explorer satellite mission that will probe the origins of our galaxy’s antimatter, uncover sites in our galaxy where complex