The term “Very Long Baseline Interferometry” (VLBI) isn’t one with which many people are familiar, but I bet that although you may not know the name you are familiar with the concept.  VLBI is a means in radio astronomy by which simultaneous observations of an object by many telescopes are combined into one image.  If your VLBI involves radio telescopes every ten miles for one thousand miles, the resultant image is as if it were made by one telescope… one thousand miles across.

Image produced by Joint Institute for VLBI in Europe

There are several VLBI arrays operating successfully, but the most sensitive is the European VLBI Network (EVN).  It’s even possible to connect arrays in Europe with those in the US (or Canada, or Japan), to have what amounts to a global radio telescope.

The image on the left was taken by UK’s MERLIN Array, while the same area is imaged on the right with EVN e-VLBI.

You know what the next step is… don’t you.

NASA/JPL  Artist rendering of HALCA (MUSES -B)

Space.

Ground-to-space VLBI link-ups already in operation (like HALCA) can provide as much as 10 times the resolution of ground-based VLBI.

Baseline interferometry is really only in its infancy.  I wouldn’t be surprised to see future link-ups stretching between the Earth and the moon.  Very likely Mars.

Goldstone DSN antenna (used for VLBI, among other things)  NASA/JPL DSN  **This is one of my favorite images**