Delta II Countdown Timeline

T- L- Event
07:20:00 MST Secure
05:20:00 Launch Mount
05:00:00 Weather Balloon Release
4:30.00 Establish Voice Communication
04:25:00 Roadblocks Up
04:25:00 Clear Blast Danger Area
04:00:00 Weather Balloon Release
02:30:00 04:00:00 Countdown Clock Initialization
HOLDING 04:00:00 Second Stage HE Fill and Pressurization
60-Minute Hold 04:00:00 Countdown Initiation
04:00:00 Countdown Briefing
04:00:00 Redundant Inertial Flight Ctrl Assembly Act.
03:55:00 Weather Balloon Release
03:22:00 Main Data Recorder Activation
03:20:00 Prepress Complete
03:20:00 SMD Poll
03:20:00 NAM Poll
03:17:00 NASA Launch Manager Poll
03:13:00 LD Poll for Terminal Count
03:11:00 LD Polls
03:10:00 Pretask Briefing
03:10:00 Launch Conductor Poll for Terminal Count
03:05:00 Launch Area Clear
02:30:00 03:00:00 Countdown Begins
COUNTING 03:00:00 Launch Area Clear Confirmation
02:27:00 02:57:00 RIFCA Activation
02:26:00 02:56:00 Core Stage He and N2 Pressurization
02:20:00 02:50:00 Second Stage He Pressurization
02:20:00 02:50:00 Guidance System activation
02:10:00 02:40:00 Core Stage Fueling
01:45:00 02:15:00 RP-1 Load Complete
01:35:00 02:05:00 Weather Briefing
01:27:00 01:57:00 NLM LOX Loading Poll
01:25:00 01:55:00 Launch Director LOX Loading Poll
01:15:00 01:45:00 LOX Loading begins
01:15:00 01:45:00 Blast Danger Area Clear
01:10:00 01:40:00 Weather Balloon Release
01:00:00 01:30:00 C-Band Transponder Beacon Checks
00:55:00 01:25:00 Weather Briefing
00:45:00 01:15:00 LOX at 100%; Systems Check
00:38:00 01:08:00 LOX Dump to 95%
00:38:00 01:08:00 Weather Balloon Release
00:37:00 01:07:00 Hydraulics System Activation
00:34:00 01:04:00 CDR Open Loop
00:26:00 00:56:00 Engine Gimbal Steering Profile Check
00:17:00 00:47:00 Link Checks
00:15:00 00:45:00 Weather Briefing
HOLDING 00:45:00 Launch Team Poll
20-Minute Hold 00:45:00 He and N2 Top Off
00:40:00 Weather Balloon Release
00:30:00 Ready Report
00:29:00 Weather Briefing
00:15:00 00:25:00 LOX Top Off to 95%
COUNTING 00:25:00 Range Safety Radio Command Carrier Act.
00:14:00 00:24:00 Range Safety Command Receiver Checks
00:14:00 00:24:00 First Stage Fuel Tank Pressurization
00:12:00 00:22:00 Wind Assessment
00:10:00 00:20:00 Load Relief
00:07:00 00:17:00 LOX Top Off to 99%
00:06:00 00:16:00 Weather Verification
00:06:00 00:16:00 Spacecraft Status Check
00:05:00 00:15:00 Launch Enable Switch to ON Position
00:05:00 00:15:00 NAM Poll
00:05:00 00:15:00 SMD Poll
00:04:00 00:14:00 Final Status Polls
HOLDING 00:12:00 Report Status
10-Minute Hold 00:11:00 NLM Poll
00:07:00 Status Check
0.06:30 Spacecraft to Internal Power
00:06:00 Launch Director GO/no GO; Range Clear
00:05:00 Spacecraft in Launch Configuration
00:04:00 00:04:00 Range Safety System armed
COUNTING 00:04:00 Launcher to internal Power
00:03:40 00:03:40 Launch Vehicle Ordnance Arming
00:03:25 00:03:25 Solid Rocket Motor Ignition System Arm
00:03:00 00:03:00 S/C Manager Status Verification
00:03:00 00:03:00 Fuel Tank Press Open
00:03:00 00:03:00 Fuel Umbilical Purge
00:03:00 00:03:00 Launch Vehicle Heater Deactivation
00:02:00 00:02:00 LOX Tank to Flight Pressure
00:02:00 00:02:00 Flight Termination System Heater Deactivation
00:01:40 00:01:40 LOX to 100%
00:01:30 00:01:30 Hydraulic External Power On
00:01:20 00:01:20 Range Status Check
00:01:10 00:01:10 Hydraulics to Internal Power
00:01:00 00:01:00 Launch Enable Switch to Flight
00:00:45 00:00:45 Main Power Disable
00:00:35 00:00:35 Hydraulics GO for Launch
00:00:30 00:00:30 LOX Fill and Drain Valve closed
00:00:13 00:00:13 GREEN Board Verification
00:00:10 00:00:10 Ignition System armed
00:00:07 00:00:07 GO for Main Engine Start
0.00:02.5 0.00:02.5 Main Engine Start
0:00:00.0 0:00:00.0 Booster Ignition
0:00:00.0 0:00:00.0 Liftoff