Delta IV Heavy Scrub Again, ULA Promises to Change Major Readiness Operations


Late Wednesday, United Launch Alliance’s big Delta IV heavy rocket arrived within seconds of lifting off its Florida launch pad again. But once again the launch was washed out.

Following the rocket’s automatic abort at T-7 seconds, both the boosters and its valuable National Reconnaissance Office payload were reported to be safe. Because the miscarriage began just before the rocket’s main RS-68 engine ignited, the delay could be less than a week before the next launch attempt.

The company reported an hour after the scrub, “The terminal countdown sequencer rack identified an unexpected condition before the engine start sequence.” “TCSR, which controls the final 10 seconds of the countdown, performed as intended and safely initiated a hold in T-7 seconds. The team is currently reviewing all data and will chart the way forward . ”

The Wednesday night miscarriage of the NROL-44 mission, coming six minutes before midnight in Florida, is just the latest setback in an effort to get the mission to the launch pad.

While it is unclear whether the root cause of the scrub is due to rocket riding or with the ground system, the United Launch Alliance is experiencing difficulties with the launch pad infrastructure at the Space Launch Complex-37, which is the Delta IV heavy booster. Supports.

This launch has been scrubbed three times, leading to delays of more than a month, due to varying ground system issues: a regulator that delivers high-pressure helium on the rocket; The swing pad retraction system of the launch pad, which draws fuel lines and other connections from the rocket just before liftoff; And a hydraulic leak in the mobile service tower.

Ars reported on Wednesday that the combination of aging infrastructure on the launch pad, which is now nearly 20 years old, and the relatively low flight rate of about one Delta IV mission a year could contribute to these delays.

The Colorado-based launch company has already retired single-core Delta IV rockets and flew four to fly Delta IV heavy rockets following the NROL-44 mission before their retirement in favor of the more cost-effective Vulcan-Centaur boosters. The bar is already planned to fly. . Only two of those four flights will be from the space launch complex-37.

In response to an investigation about these issues ahead of Wednesday night’s scrub, United Launch Alliance chief Tory Bruno told Aers, “The low Delta launch tempo is definitely a factor. We are in order for the remaining Delta IV heavy missions. Readiness of our operations will change the process. To avoid the type of issues seen here. ”

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