On January 31, 2026, the kick-off meeting and scientific workshop for the LAgrange-V Solar Observatory (LAVSO) mission, dubbed as Xihe-2, were held at Nanjing University, marking the entry of the project into the development phase.
Approved by the China National Space Administration (CNSA) in December 2025, Xihe-2 is scheduled for launch between 2028 and 2029. The mission will, for the first time, deploy an artificial spacecraft to the Sun–Earth L5 Lagrange point, aiming to explore previously uncharted regions of the solar system and to carry out sustained observations of the Sun and the interplanetary space environment.
The L5 point, one of five equilibrium points in the Sun-Earth system, occupies a strategically advantageous position at 60° heliocentrically ahead of Earth in its orbit and at the upstream of solar rotation. This unique orbital configuration offers several critical advantages for solar observations: providing accurate vector magnetic field measurements, revealing 3D structure and evolution of solar eruptions, detecting emerging active regions before they become Earth-facing, and monitoring thepropagation of solar eruptions towards the Earth.
Xihe-2 carries five scientific payloads: Spectral Magnetic Telescope (SMT), L5 Extreme ultraviolet Coronal Imager (LECI), Imaging PAckage of Corona and Heliosphere (IMPACH), High-Energy solAR Telescope (HEART), and Package of In-situ Sensors (PINS), to address two fundamental questions in solar physics and space weather, i.e., "How do the active-region magnetic fields evolve and what are their roles in producing solar eruptions?" and "How do the solar eruptions propagate in interplanetary space and what determine their space weather impacts?"