The Swift mission observes gamma-ray bursts and probes conditions in the distant (high-redshift) universe. The mission consists of three instruments on a spacecraft that can rapidly reorient itself to observe new targets. Within seconds of detecting a burst, Swift relays a burst's location to ground stations. This enables both ground-based and space-based telescopes around the world to target and observe the burst's afterglow. The spacecraft observes approximately 90 gamma-ray bursts per year. Additionally, it observes other transient sources of many types, such as, supernovae, novae, tidal disruption events, black hole transients, and comets. Swift was launched in 2004, and renamed the Neil Gehrels Swift Observatory in 2018.