The Firefly (4π) Constellation: Going Above and Beyond in the Heliosphere Exploration

Over the last few decades, heliospheric exploration reached unprecedented heights thanks to innovative spaceborne missions and ground-based observatories. However, the inner-heliospheric research is severely hampered by observing limitations preventing the science community from resolving long-standing problems, such as the solar dynamo, solar cycle, magnetic fields, solar activity, space weather, the solar wind, energetic particles, and the impact on the Earth climate. These limitations are primarily due to observing a high-dynamics (3D) star from a single vantage point. Holistic observations (i.e., 4π-steradian coverage) of the Sun will open new research avenues that were not accessible before and will lead to close long-standing knowledge gaps in heliophysics and the closure of challenging astrophysical phenomena. The Firefly Constellation is an innovative mission concept allowing simultaneous full 4π-steradian observations of the Sun and its environments. Firefly is a unifying, cross-disciplinary mission that will revolutionize our understanding of the Sun’s interior, the solar atmosphere, and the inner heliosphere by providing unprecedented multi-viewpoint observations optimized for continual global coverage over much of a solar cycle. Firefly includes two spacecraft in the ecliptic plane and two flying as high as 70◦ solar latitude. The appeal of a mission such as Firefly is unprecedented, making it among the highest priorities of the international science community. We provide an overview of the Firefly mission concept, under consideration by the 2024-2033 Decadal Survey for Solar and Space Physics (Heliophysics), and show why Firefly must be given a high priority to overcome decades-long astrophysics challenges.