The Russian space agency’s RadioAstron satellite, launched in July, is the final piece of the biggest radio-telescope array ever assembled. The satellite’s 33-foot carbon-fiber dish antenna is small, but it connects it to a worldwide network of terrestrial telescopes. Using a technique called very long baseline interferometry, the satellite completes a virtual dish that is 30 times the size of Earth and has a resolution 10,000 times that of Hubble. Scientists will use it to study dark matter and black holes, and maybe even to determine whether the center of our galaxy contains a wormhole.