ULA Delta 4 Heavy rocket launch aborted seconds before liftoff

The United Launch Alliance was set to launch a rocket in the early morning hours of August 29. The launch of the ULA Delta 4 Heavy rocket was meant to put a National Reconnaissance Office classified spy satellite into orbit. Liftoff was planned for 3:28 AM Eastern but was aborted during the ignition sequence.Launch of NROL-44 was aborted only three seconds before liftoff from Space Launch Complex-37 at Cape Canaveral Air Force Station in Florida. The automatic abort was triggered by hot fire after the Delta 4 Heavy's three engines appeared to ignite but then shut off. ULA CEO Tory Bruno said via Twitter that the aborted launch's cause appears to have been in the ground system.

Bruno says that the abort system functioned as intended to protect the vehicle and payload. The company is currently reviewing all the data and intends to determine a path forward to put the satellite in orbit. The soonest another launch can happen will be seven days.

The aborted launch was the third launch attempt after two launches were previously scrubbed. The customer canceled a launch on August 26. A launch on August 27 scrubbed due to a technical problem with a grounded pneumatics control system.

Interestingly, the launch scheduled early this morning had been postponed from its original launch time of 2:04 AM. The launch was pushed back due to a thermal anomaly resulting from a lower-than-expected temperature and one rocket compartment. That issue was rectified, and the launch process begins later only to be ultimately canceled by an automated system.