Delta 4000 Series
The Delta 4000-series and 5000-series were developed in the aftermath of the Challenger disaster and consisted of a combination of 3000-era and Delta II-era components. The first stage had the MB-3 main engine and Extended Long Tank of the 3000-series and mounted upgraded Castor 4A motors. The new Delta K second stage was also included.
Missions: 2
Successes: 2
Partial Failures: 0
Failures: 0
Success Streak: 2
Success Rate: 100%