| 05:15:00 |
Countdown Clock Initialization |
| HOLDING |
Countdown Initiation |
| HOLDING |
Countdown Briefing |
| 05:00:00 |
Redundant Inertial Flight Control Assembly Activation |
| 04:50:00 |
Launch Area Clear |
| 04:35:00 |
Go/No GO for Propellant Loading |
| 04:30:00 |
Cryogenic Tanking begins |
| 04:30:00 |
Common Booster Core LH2 Tank Chilldown |
| 04:10:00 |
Common Booster Core LH2 Loading in Slow Fill |
| 04:00:00 |
CBC LH2 Load Transitions to Fast Fill |
| 04:00:00 |
Common Booster Core LOX Tank Chilldown |
| 03:50:00 |
Common Booster Core LOX Loading in Slow Fill |
| 03:45:00 |
CBC LOX Load Transition to Fast Fill |
| 03:35:00 |
C-Band Beacon Checkouts, GPS Verifications |
| 03:25:00 |
Delta Cryogenic Upper Stage LH2 Tank Chilldown |
| 03:25:00 |
Guidance System Activation |
| 03:10:00 |
CBC LH2 Topping – Fill & Drain Valve Checks |
| 03:05:00 |
DCSS LH2 Loading |
| 02:55:00 |
CBC LOX Topping – Fill & Drain Valve Checks |
| 02:45:00 |
Delta Cryogenic Upper Stage LOX Tank Chilldown |
| 02:45:00 |
Launch Weather Briefing |
| 02:35:00 |
DCSS LOX Loading |
| 02:00:00 |
DCSS LH2 Topping |
| 01:35:00 |
DCSS LOX Topping |
| 01:25:00 |
Radio/Telemetry Link Checks, FTS Checks |
| 01:10:00 |
Command Receiver Decoder Testing |
| 01:00:00 |
Flight Termination System Testing complete |
| 00:50:00 |
RS-68 Engine Spin Start Pressurization |
| 00:50:00 |
RS-68 Gimbal Steering Checks |
| 00:25:00 |
Weather Briefing |
| 00:08:00 |
Launch Pad Ordnance Armed |
| T-4 Minutes |
Weather Update |
| HOLDING |
Spacecraft to internal power |
| HOLDING |
Final Status Polls |
| HOLDING |
Launch Director GO/no GO; Range Clear |
| 00:04:00 |
Delta IV to internal Power |
| 00:04:00 |
Arm Safe and Arm Switches |
| 00:04:00 |
DCSS Tank Propellant Securing |
| 00:03:30 |
Transfer to Internal complete |
| 00:03:30 |
Common Booster Core Propellant Tank Securing |
| 00:03:15 |
CBC Pre-Press |
| 00:03:00 |
Common Booster Core LOX secure at Flight Level |
| 00:03:00 |
Common Booster Core LH2 secure at Flight Level |
| 00:03:00 |
Vehicle Ordnance Arming |
| 00:03:00 |
CBC LOX at Flight Level and Flight Pressure |
| 00:02:00 |
Master Script Running |
| 00:02:00 |
Second Stage LOX Securing |
| 00:02:00 |
Hydraulic System to Flight Pressure |
| 00:01:45 |
CBC LH2 at Flight Level and Flight Pressure |
| 00:01:30 |
Second Stage LOX secured at Flight Level |
| 00:01:20 |
Second Stage LH2 Securing |
| 00:01:20 |
LOX Ground Support Equipment secured |
| 00:01:00 |
Range Verification |
| 00:00:50 |
Second Stage LH2 secure at Flight Level |
| 00:00:45 |
Launch Enable |
| 00:00:45 |
Main Power Off |
| 00:00:25 |
Green Board |
| 00:00:15 |
Launch Vehicle Igniters armed |
| 00:00:14 |
Radially Outward Firing Initiators Ignition |
| 00:00:10 |
Terminal Countdown Sequencer in Control |
| 00:00:07 |
Starboard RS-68 Main LH2 Valve Open |
| 0:00:05.5 |
Center & Port RS-68 LH2 Valve Open |
| 0:00:03.5 |
Starboard RS-68 LOX Valve Open |
| 0:00:02.0 |
Center & Port RS-68 LOX Valve Open |
| 0:00:02.0 |
RS-68 Main Engines to Full Thrust Level – 102% |
| 0:00:00.04 |
Launch Commit |
| 0:00:00.00 |
Hold-Down Release |
| 0:00:00.00 |
LIFTOFF |
