ULA finds cause of dramatic Delta IV Heavy launch scrub; targeting new date

The new launch will happen no earlier than next week

ULA's Delta IV Heavy rocket at Launch Complex 37. (Image: ULA) (WKMG 2020)

United Launch Alliance teams have determined the cause behind a Delta IV Heavy rocket’s dramatic, last-second abort late last month, setting the stage for another attempt no earlier than next week, News 6 partner Florida Today reports.

A torn diaphragm in one of three pressure regulators at Cape Canaveral Air Force Station’s Launch Complex 37 caused the computer-controlled scrub just three seconds before liftoff on Aug. 29, ULA CEO Tory Bruno said via Twitter on Wednesday. The engines briefly lit on fire, but the rocket remained firmly on the pad.

“Torn diaphragm (in the regulator), which can occur over time,” Bruno said. “Verifying the condition of the other two regulators. We will replace or rebuild as needed, re-test, and then resume towards launch.”

He said teams are currently targeting no earlier than Friday, Sept. 18, for the next pre-dawn attempt. An exact time has not yet been released.

If the timeline holds, it will actually mark Delta IV Heavy’s third attempt to launch a secretive intelligence-gathering satellite for the National Reconnaissance Office known as NROL-44. The first launch on Aug. 27 was scrubbed due to a pneumatics issue in ground support equipment.

Elsewhere on the Eastern Range, SpaceX is tentatively targeting about 12 hours before Delta IV Heavy – so next Thursday afternoon – for its next mission from Kennedy Space Center’s pad 39A. The Falcon 9 flight will take the company’s 13th batch of roughly 60 Starlink internet satellites to orbit and see the first stage land on a drone ship in the Atlantic Ocean.