A Heliocentric Satellite Constellation for Continuous Solar Coverage and Space Weather Monitoring

While the Sun provides the Earth with the energy needed to sustain life, the volatility associated with this intense energy source generates solar weather, which can have devastating implications on Earth. Solar weather can result in data compromise, radio interference, premature satellite deorbit, and even failure of the power grid. To mitigate the negative effects of solar weather, constant observation of the entirety of the Sun’s surface is essential. This complete picture of the Sun’s ever-changing state will help scientists anticipate solar events that may negatively impact life on Earth. A heliocentric satellite constellation called the Solar Unobstructed Network-based First Long-term Outer-space Weather Effects Research (SUNFLOWER) Observatory is proposed to continuously monitor coronal mass ejections, sunspots, and coronal holes with a suite of science instruments capable of collecting data in various electromagnetic wavelengths. This report offers a holistic view of the mission and spacecraft architectures. The paper begins with a discussion of motivation, mission objectives, and influential past missions. Next, a high-level overview of the mission design flow, mission-level requirements, and cost and schedule estimation assumptions is explored. This is followed by an analysis of the stakeholders and associated value flows and identification of system boundaries. Next, high-level design decisions for critical components of the system architecture and project risks and risk mitigation strategies are discussed. Results for instrument selection, constellation design, and spacecraft design are presented along with the reasoning behind the recommended architectures and design decisions. The final result is an estimate of the overall mission cost and schedule—roughly $4B in FY2025 USD over an 18-year lifecycle beginning in FY2025. The conclusion summarizes the proposed constellation, composed of nine identical spacecraft—each containing a magnetograph, an extreme ultraviolet imager, and a coronagraph—in a Walker-Delta 54.7° configuration at one AU, with three spacecraft in each of three planes. This solution offers continuous 4π-steradian remote sensing coverage of the solar surface—including the poles—with daily communication of science and state-of-health data over Ka-band frequencies to Earth using 34-m ground stations within the Deep Space Network (DSN). To circumvent the significant burden that would be placed on DSN, a compelling and mutually beneficial case for investing in additional 34-m antennas is presented. The paper concludes with recommendations for future work on the SUNFLOWER Observatory.