I imagine the same way the article's array does: with an (interplanetary) version of sneakernet [0], taking independent measurements which are then delivered to

I imagine the same way the article's array does: with an (interplanetary) version of sneakernet [0], taking independent measurements which are then delivered to be correlated in one place. I think you could keep atomic clocks on Mars and Earth in sync with extremely accurate calculation of the Earth-Mars distance at any time, and thus the propagation delay between them. EDIT: only one star!! [0] https://en.wikipedia.org/wiki/Event_Horizon_Telescope#/media/File:EHT-infography.jpg https://en.wikipedia.org/wiki/Event_Horizon_Telescope#/media...