ULA's Vulcan Centaur Rocket Faces Delays and Returns to Factory for Fixes

United Launch Alliance (ULA) has sent the upper stage of its Vulcan rocket back to the factory for reinforcements after a test article exploded during a structural test. ULA engineers have determined that the upper stage needs more work, delaying the first flight of the Vulcan rocket until at least the fourth quarter of this year. The Vulcan rocket is set to replace ULA's Atlas and Delta launch vehicles and is crucial for the US military's satellite launches. The issue with the upper stage's fuel tank is considered minor and can be easily fixed.