Delta II
Delta II vehicles included the Delta 6000, and the two later Delta 7000 variants ("Light" and "Heavy"). The rocket flew its final mission ICESat-2 in September 2018, earning the launch vehicle a streak of 100 successful missions in a row, with the last failure being GPS IIR-1 in 1997.
After the Challenger disaster, President Ronald Reagan announced in December 1986 that the Space Shuttle would no longer launch commercial payloads, and NASA would seek to purchase launches on expendable vehicles for missions that did not require crew or Shuttle support. Many of these launches thus were moved to Delta II. The rocket also launched numerous payloads for the United States Air Force including many Global Positioning System (GPS) satellites.
Missions: 155
Successes: 153
Partial Failures: 1
Failures: 1
Success Streak: 100
Success Rate: 99.0%