The Quadros-1 probe was a probe launched by the United Federation of Planets in 2193 to explore the Gamma Quadrant and to send back data on the information it collected.
In 2369, after Benjamin Sisko and Jadzia Dax entered the Gamma Quadrant through the Bajoran wormhole, the main computer of the USS Rio Grande identified Idran based on the hydrogen alpha spectral analysis conducted by Quadros-1. (DS9 episode: "Emissary")
Quadros-1 was still active in 2369 and was nearing Quasar M39. (ST reference: Star Charts)