The Atlas V launch has been delayed for safety precautions in order to shield the rocket and payload from any effects of Hurricane Idalia. When a new launch date is announced, it will take place from Space Launch Complex 41 at Cape Canaveral Space Force Station.
The Atlas V will be launching a secretive payload, NROL 107 / Silentbarker, for the National Reconnaissance Office (NRO) and the United States Space Force.
The sun sets and rises over the #AtlasV 551 rocket that will launch #SILENTBARKER / #NROL107, a joint @NatReconOfc and @SpaceForceDoD capability to improve space domain awareness. Launch is tomorrow, Aug. 29 at 8:34 a.m. EDT (1234 UTC).
— ULA (@ulalaunch) August 28, 2023
With Hurricane Idalia approaching Florida bringing widespread storms and strong winds across a majority of the state, including the Space Coast. ULA decided yesterday evening to make the decision to roll the Atlas V back to the Vertical Integration Facility to protect it from the storm.
Once the hurricane is clear of Florida and teams move the rocket back to the launch pad, it will send the NRO payload on an Easterly trajectory which is about all we will find out as the NRO does not give specifics regarding its secretive payloads. It is likely that satellite spotters will locate the payload days after the launch, which will be about the only confirmation that is given regarding its orbit.
The rocket launching this mission is the most powerful variant of the Atlas V, the 551, it features 1 Russian-made RD-180 engine with dual nozzles and 5 strap-on GEM-63 solid rocket boosters built by Northrop Grumman and a 5-meter fairing.
This will be the final Atlas V mission for the National Reconnaissance Office, previously successfully launching 17 payloads to orbit.
This mission, the first Atlas V of the year, 2nd total for United Launch Alliance, is a bit of an unexpected lull for the company. They were ready to launch the Starliner capsule to the ISS earlier this year, but that mission is now delayed indefinitely as Boeing works through issues on the capsule.
The company was also planning on launching the replacement to the Atlas V, the Vulcan rocket, earlier this year, but it was also hit with delays after a test of the 2nd stage went wrong and exploded on the test stand. ULA still plans to get that launch off the ground in Q4 of this year.