10|11799|24Sep2022 15:40:18 Pacific
Great final launch of Delta IV from Vandenberg
24Sep2022 15:22:23 Pacific
T-4 and Counting
The countdown clock has restarted and we are go for launch.
24Sep2022 15:21:47 Pacific
Terminal poll: GO for Launch
The Launch Conductor has just taken the terminal count poll and all Stations, Range and Launch Director have reported go for launch. The Mission Director has just given the Launch Conductor permission to launch!
24Sep2022 15:15:57 Pacific
Weather is GO
The weather officer has confirmed that the weather is currently green and upper level winds are within limits. Solar limits are within limits as well
24Sep2022 15:15:57 Pacific
Weather is GO
The weather officer has confirmed that the weather is currently green and upper level winds are within limits. Solar limits are within limits as well
24Sep2022 15:12:50 Pacific
Payload is on internal power
The NROL payload is configured for launch and is on internal power.
24Sep2022 14:57:02 Pacific
Final Delta launch from SLC-6
With the launch today ULA will close out the operations of Delta IV rockets from Vandenberg's Space Launch Complex 6.
24Sep2022 14:35:23 Pacific
Hold will be extended
There is an issue with the second stage LH2 equipment and the hold will be extended to 22:25GMT 3:25 Pacific, 7:25 Eastern
24Sep2022 14:33:05 Pacific
T-4 and holding
The countdown has just entered the final planned hold of the launch. This will last for 16 minutes and will be released after the poll for terminal countdown has been successfully taken.
During the hold the launch teams have a chance to catch up with any outstanding tasks and the Launch Controller, Scott Barney, will ensure that all teams, stations and payload are ready for launch.
24Sep2022 14:15:45 Pacific
Weather is holding at 90% Go
The weather is still 90% GO and the launch teams are not working any significant issues at this time.
24Sep2022 14:02:39 Pacific
The launch video feed will go live in about 30 minutes.
The launch video will be live in just under 30 minutes. The coverage will continue for the remaining countdown and terminate just over 6 minutes into the flight. This is just after payload fairing separation and is at the request of the NRO. This is standard operating procedure for the secret NROL missions.
24Sep2022 13:55:14 Pacific
L-1 hour
The L-1 hour mark has just passed which is L-44 minutes. The discrepancy of 16 minutes is to cater for a planned 16 minute built in hold which will occur at T-4 minutes.
24Sep2022 13:51:59 Pacific
The Delta IV Heavy rocket has a common core booster which is a main booster with two similar boosters either side. Each of these boosters has a single RS-68A engine which produces over 700,000Lbs of thrust.
On top of the central booster is the interstage which mates the second stage to the booster.
Then comes the Delta Cryogenic Second Stage which will loft the payload into orbit.
At the top of the stack is the Payload. In this instance it is a top secret satellite for the NRO. The satellite is protected on it's flight through the atmosphere by the Payload Faring. This will be jettisoned shortly after the booster has separated and the rocket is flying in the thinner part of the atmosphere.
24Sep2022 13:38:51 Pacific
Fuelling of the Delta IV rocket is nearing completion
The four modules of the Delta IV heavy rocket are nearly filled with propellants.
The three common core boosters and the Delta Cryogenic Second Stage all use LH2 which is oxidised by LOX. LH2 is liquid hydrogen and LOX is liquid oxygen.
The filling of the 8 tanks starts slowly then moves to a fast fill mode, as the tanks get close to full the fuelling transitions to topping off mode and finally when they are full to replenishment mode.
24Sep2022 9:08:00 Pacific
Weather is GO for tanking operations
The weather officer for today's launch, Captain Isabella Relyea has confirmed that the weather is go for the start of fuelling operations. The weather remains at 90% go during the launch window.
The launch conductor has issued the command for teams to leave the launch pad in preparation for the start of fuelling.
24Sep2022 7:54:31 Pacific
Viewing opportunities for NROL-91
If you want to know when you can see the launch of the Delta IV and NROL-91 from locations across California then take a look at the graphic below:
21Sep2022 5:03:25 Pacific
NROL-91 lowered onto the Rocket
The enshrouded NROL-91 satellite is gently lowered in preparation for mating with the Delta Cryogenic Second Stage on Space Launch Complex 6.
21Sep2022 4:59:52 Pacific
NROL-91 hoisted in the VIF
With the Delta IV Heavy in the Vertical Integration Facility the NROL-91 payload is being hoisted into place enclosed in the payload fairing.
21Sep2022 4:56:38 Pacific
Triple core booster of Delta IV
The triple core booster of the Delta IV leaves the Horizontal Integration Facility with the Delta Cryogenic Second Stage attached to the central core.
Sep 24 - Delta IV Heavy : NROL-91
Launch site Vandenberg AFB, CA
Launch Date Sep 24
From Launch Pad SLC-6
Launch Window : 3:25pm Pacific (6:25pm Eastern 22:25 GMT)
United Launch Alliance will launch a Delta IV rocket from Vandenberg Space Force Base in California. The payload for this mission will be the National Reconnaissance Office classified satellite codenamed NROL-91.
The Delta IV will fly in the heavy configuration with a triple core, a Delta cryogenic second stage and the payload. This will mark the final Delta IV launch from the west coast of the USA.
