The Comet Interceptor mission launches without a target. The spacecraft freezes at a point of space equilibrium, like a fighter jet on combat standby: engine warmed up, but takeoff only on alert. When telescopes spot a new long-period comet, the probe bolts from its spot and races past at immense speed, capturing data on primordial matter.
Now this audacious tactic wants to be applied to interstellar objects — wanderers ejected from other planetary systems. 'Oumuamua and Comet Borisov were spotted only as they were leaving the vicinity of the Sun; the chase was too late. In an upgraded version, the interceptor will wait even more patiently. A twist: the encounter will last mere minutes. The probe doesn't brake: it zips by at tens of kilometers per second, doing in moments what would take ordinary missions years. Spectroscopy instruments will split the light to tease out the composition and origin of material from other corners of the galaxy. In essence, for the first time we'll study alien matter without leaving home, as if we intercepted a foreign drone and read its secrets on the fly.
The first interstellar object, 'Oumuamua, resembled a cigar tumbling chaotically in the void. It was spotted only on its way out, as it was already moving away from the Sun.
Arthur C. Clarke in 'Rendezvous with Rama' described the appearance of a mysterious interstellar cylinder, and this mission could become a real rendezvous with a similar object.