The Very Long Baseline Array (VLBA) is a system of ten radio telescopes controlled remotely from the Array Operations Center in Socorro, New Mexico (USA) by the National Radio Astronomy Observatory. The array works together as the world’s largest dedicated, full-time astronomical instrument using the technique of very long baseline interferometry. Its construction began in February 1986, and was completed in May 1993. The first observation using all ten sites occurred on May 29, 1993. The total construction cost was US$85 million.