Concept of the Solar Ring mission: Preliminary design and mission profile

The Solar Ring mission, a concept to monitor the Sun and inner heliosphere from multiple perspectives, has been funded for pre-phase study by the Strategic Priority Program of Chinese Academy of Sciences in space sciences. The Solar Ring is comprised of 6 spacecraft, grouped in three pairs, moving around the Sun in an elliptical orbit in the ecliptic plane. The mission costs, including launch fee, deep-space maneuvers, and deployment time of the ring, are highly relevant to the working orbit, deep-space transfer, and phase angle within a group. The preliminary mission profile is analyzed and designed in this paper. The launch way, two spacecraft with one rocket, is adopted. The deployment time, phasing maneuvers, and C3 of launch energy are evaluated for the elliptical orbits with the perihelion between 0.7 and 0.9 AU using the rockets of Long March (LM) 3A and 3B. Numerical simulations show two candidate trajectories: fast deployment within 4 years by LM-3B, medium deployment more than 6 years by cheaper rocket of LM-3A. In order to obtain both fast deployment and low launch cost, another orbit profile is proposed by shortening the phase angle within a group. The suggested working orbits and the corresponding costs of launch, deployment time, and phasing maneuvers will strongly support the science objectives.