Space VLBI-exploring the potential of hybrid orbit configurations

Abstract

Space-Based Very Long Baseline Interferometry (SVLBI) significantly enhances the resolution and sensitivity of radio astronomical observations by placing radio telescopes in orbit. However, designing an effective satellite constellation for SVLBI is complex, as it involves multiple factors such as imaging performance, (u, v) coverage, resolution, and image fidelity. This paper is the first in a series focused on evaluating the (u, v) coverage capabilities of different satellite configurations. We investigated several constellation designs, including hybrid configurations that combine satellites in various orbital regimes. These hybrid setups demonstrated superior performance compared to those using satellites in a single orbit. Notably, a configuration with five satellites—three in Medium Earth Orbit (MEO) and two in Low Earth Orbit (LEO)—achieved the most uniform and dense (u, v) coverage with the fewest satellites. Finally, the most effective configurations were further tested using simplified simulations involving both point sources and extended sources to assess their practical imaging capabilities. © 2025 Elsevier B.V., All rights reserved.