NASA's Goddard Space Flight Center (GSFC) is seeking partners for the development of a Heliophysics Medium Explorer (MIDEX) mission concept, which involves deploying three to four identical spacecraft equipped with multiple scientific instruments on booms to study ion flux and energy inputs in the Earth’s exobase transition region. The procurement aims to select a spacecraft integrator and partners for providing instrument booms, emphasizing compliance with NASA's Class C mission standards and the necessity for detailed proposals that include spacecraft and boom designs, integration processes, and cost estimates capped at $300 million. This initiative is crucial for advancing space research and understanding solar and space weather phenomena, with key deadlines including the release of a draft announcement in FY2025 and a projected launch readiness date around 2032. Interested parties should contact Laura Ottenstein at Laura.Ottenstein-1@nasa.gov or Kelly Collins at kelly.collins@nasa.gov for further information and to express their interest.