Spaceflight Insider

Hot Fire Abort safely keeps Delta IV Heavy, NROL-44 on the ground

Smoke dissipates from SLC 37B following the hot-fire abort during the August 29, 2020 launch attempt of the NROL-44 mission. Photo: Matt Haskell, SpaceFlight Insider

A hot fire abort was called at T-3 seconds, after ignition of engines aboard the Delta IV Heavy but prior to the vehicle being released for flight. The vehicle was quickly safed and made secure, as launch teams verified the status of all resources and the state of affairs at the launch pad itself.



The abort occurred at 3:28 a.m. EDT, which was a revised T-zero time following the working of a pre-launch anomaly related to unexpected internal vehicle compartment temperature being too low. After close review by the ULA team, it was determined that the vehicle’s flight path would include a significant amount of time flying in sunlight, which would help in keeping required temperatures. The aborted ignition was 64 minutes following the planned ascent time of 2:04 a.m. EDT.

ULA CEO Tory Bruno tweeted, “The bird is in good shape. This was an automatic abort during the ignition sequence. Cause appears to have been in the ground system. System functioned as intended to protect the vehicle and payload.”


Delta IV Heavy engines ignited, but were quickly shut down as part of a hot-fire abort which occurred at 3:28 a.m. EDT, August 29, 2020. Photo: Theresa Cross, SpaceFlight Insider.

A new launch time has not been set at this time; ULA has confirmed that there will be a minimum 7 day recycle period before the next launch attempt. We will edit this article with new launch date and time details when released by ULA.



Sean Costello is a technology professional who also researches, writes about and speaks publicly on the inspiring lessons within international space flight program. Prior to joining SpaceFlight Insider in early 2014, Costello was a freelance photographer and correspondent covering shuttle-era Kennedy Space Center launches for various radio and print news organizations.

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