Cislunar Space VLBI Arrays for Improved $uv$ Coverage and Angular Resolution

Space Very Long Baseline Interferometry (SVLBI) can significantly improve angular resolution by extending interferometric baselines beyond Earth's diameter. China is actively promoting the development and scientific applications of SVLBI, including the proposal to deploy a radio telescope on the lunar surface through the International Lunar Research Station (ILRS), as well as the long-term goal of establishing a cislunar SVLBI array. In this research, the \enquote{lunar far side configuration} refers to placing a telescope directly at the lunar south pole, while the \enquote{multiple space configuration} broadly encompasses telescopes in lunar orbit, in Earth orbit, and at equilibrium points such as the Earth-Moon L2 or Sun-Earth L2. Based on detailed simulations with multiple configurations derived from the Event Horizon Telescope (EHT) ground network, we systematically evaluate the uv coverage and angular resolution of the proposed SVLBI array. The results show that: (1) in the lunar far side configuration, deploying a telescope extends the baseline and improves uv coverage, but only yields limited gains in angular resolution; (2) in the multiple space configuration, deploying telescopes achieves substantial improvements in both $uv$ coverage and angular resolution, owing to the significantly longer baselines. These findings provide important theoretical and technical support for the future development of SVLBI in China.