SSED stands for the Solar System Exploration Division, a specific research branch within NASA. This division focuses on robotic missions and scientific studies aiming to understand the formation, evolution, and state of our solar system. Scientists and engineers in this division analyze data from planetary probes, manage instrument development, and plan deep-space missions.
SSED released the preliminary data from the asteroid flyby for the instrument teams to review.
When researchers mention SSED, they are usually referring to the specific science teams at Goddard Space Flight Center who handle planetary geology, astrochemistry, and planetary environments.