For decades, heliophysics research focused primarily on a top-down model, tracking how solar flares, coronal mass ejections, and solar winds strike the upper atmosphere. Modern scientific assessments now indicate that a significant portion of upper-atmosphere variability is driven from the bottom up, pushed by weather patterns, temperature fluctuations, and wind vectors originating closer to Earth’s surface. DAPHNE was originally proposed as a tailored concept study in response to NASA’s Dynamical Neutral Atmosphere-Ionosphere Coupling, or DYNAMIC, opportunity, a structural priority within the National Academy of Sciences’ Heliophysics Decadal Survey.
The DAPHNE architecture deploys identical twin satellites flying in tandem through very low-Earth orbit. Operating as a coordinated pair, the spacecraft will capture multi-point, simultaneous measurements within the thermosphere and ionosphere, the volatile boundary shell where Earth’s neutral atmosphere transitions into the ionized plasma of space. Each satellite carries three remote-sensing instruments: the Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI), the Far Ultraviolet Ionospheric Imager (FUVI), and the Plasma Analysis Telescope for Orbit (PLATO). Together the payload suite will deliver data on neutral winds, ambient temperature, and gas composition.
The mission is led by Principal Investigator Aimee Merkel of the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder. LASP is partnering with BAE Systems Space and Mission Systems in Boulder for spacecraft manufacturing and the Naval Research Laboratory in Washington, D.C., for core instrument integration. Phase B will focus entirely on refining flight architectures, finalizing instrument design, and mapping out mission operations. The program is structured as a low-risk, high-heritage project using proven engineering frameworks to maximize data return per dollar spent.
“DAPHNE will fill this major gap in scientific understanding and help answer long-standing questions about how Earth interacts with our sun,” Merkel said following the selection. Incorporating lower-atmospheric energy data into active space weather models is intended to give researchers the clarity needed to track how energy moves upward through the orbital column.
Following Phase B, the mission will face a formal NASA confirmation review in 2027 to assess development progress and allocate final flight funds. If confirmed, the total cost cap is strictly limited to $250 million in fiscal year 2023 dollars, excluding launch procurement, with a targeted launch window opening no earlier than 2029. Management oversight will run through the Solar Terrestrial Probes program at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.