Editor's Note: The launch window is roughly 10 minutes long. To maximize ascent performance, NASA targets the middle of the window. A final hold in the countdown at the T-minus nine-minute mark will be extended as required to hit the desired launch time.

HH...MM...SS...EDT...........EVENT

Tue  07/05/11

...............12:30 PM......Call to stations
70...21...00...01:00 PM......Countdown begins
60...21...00...11:00 PM......Fuel cell reactant load preps

Wed  07/06/11

54...51...00...04:30 AM......MEC/SRB power up
54...21...00...05:00 AM......Clear crew module

54...21...00...05:00 AM......Begin 4-hour built-in hold
54...21...00...05:00 AM......Clear blast danger area
53...36...00...05:45 AM......Orbiter pyro-initiator controller test
53...26...00...05:55 AM......SRB PIC test
52...26...00...06:55 AM......Master events controller pre-flight BITE test
50...21...00...09:00 AM......Resume countdown

48...51...00...10:30 AM......Fuel cell oxygen loading begins
46...21...00...01:00 PM......Fuel cell oxygen load complete
46...21...00...01:00 PM......Fuel cell hydrogen loading begins
43...51...00...03:30 PM......Fuel cell hydrogen loading complete
42...51...00...04:30 PM......Pad open; ingress white room

42...21...00...05:00 PM......Begin 4-hour built-in hold
41...51...00...05:30 PM......OMBUU demate
41...21...00...06:00 PM......Crew module clean and vacuum
39...21...00...08:00 PM......Remove APU vent covers
38...51...00...08:30 PM......MPS 2000 PSI test
38...21...00...09:00 PM......Countdown resumes

38...21...00...09:00 PM......Main engine preps
38...21...00...09:00 PM......MECs 1 and 2 on; avionics system checkout

Thu  07/07/11

35...21...00...12:00 AM......LO2/LH2 feedline inspection
31...51...00...03:30 AM......Deflate RSS dock seals; tile inspection
31...21...00...04:00 AM......Tile inspection
30...56...00...04:25 AM......TSM prepped for fueling

30...21...00...05:00 AM......Begin 14-hour 6-minute hold
27...51...00...07:30 AM......RSS rotation preps
27...51...00...07:30 AM......OIS communications check with JSC
27...36...00...07:45 AM......Crew weather briefing
27...01...00...08:20 AM......JSC flight control team on station
26...21...00...09:00 AM......L-1 engineering briefing
25...51...00...09:30 AM......Comm activation
25...21...00...10:00 AM......Crew module voice checks
24...21...00...11:00 AM......Flight crew equipment late stow
21...21...00...02:00 PM......RSS to park position
21...21...00...02:00 PM......Ascent switch list
20...21...00...03:00 PM......Final TPS, debris inspection
16...20...00...07:01 PM......Resume countdown

16...00...00...07:21 PM......Pad clear of non-essential personnel
16...00...00...07:21 PM......APU bite test
15...10...00...08:11 PM......Fuel cell activation
14...20...00...09:01 PM......Booster joint heater activation
13...50...00...09:31 PM......MEC pre-flight bite test
13...35...00...09:46 PM......Tanking weather update
12...50...00...10:31 PM......Final fueling preps; launch area clear
12...20...00...11:01 PM......Red crew assembled
11...35...00...11:46 PM......Fuel cell integrity checks complete

Fri  07/08/11

11...20...00...12:01 AM......Begin 2-hour built-in hold (T-minus 6 hours)
11...10...00...12:11 AM......Safe-and-arm PIC test
10...32...00...12:49 AM......Crew wakeup
10...20...00...01:01 AM......External tank ready for loading
10...02...00...01:19 AM......Mission management team tanking meeting
09...26...00...01:55 AM......NASA TV fueling coverage begins
09...20...00...02:01 AM......Resume countdown (T-minus 6 hours)

09...20...00...02:01 AM......LO2, LH2 transfer line chilldown
09...10...00...02:11 AM......Main propulsion system chill down
09...10...00...02:11 AM......LH2 slow fill
08...40...00...02:41 AM......LO2 slow fill
08...35...00...02:46 AM......Hydrogen ECO sensors go wet
08...30...00...02:51 AM......LO2 fast fill
08...20...00...03:01 AM......LH2 fast fill
06...25...00...04:56 AM......LH2 topping
06...20...00...05:01 AM......LH2 replenish
06...20...00...05:01 AM......LO2 replenish

06...20...00...05:01 AM......Begin 2-hour 30-minute built-in hold (T-minus 3 hours)
06...20...00...05:01 AM......Closeout crew to white room
06...20...00...05:01 AM......External tank in stable replenish mode
06...17...00...05:04 AM......Ascent flight control team on console
06...05...00...05:16 AM......Astronaut support personnel comm checks
05...35...00...05:46 AM......Pre-ingress switch reconfig
05...26...00...05:55 AM......NASA TV launch coverage begins
04...25...00...06:56 AM......Final crew weather briefing
04...15...00...07:06 AM......Crew suit up begins
03...50...00...07:31 AM......Resume countdown (T-minus 3 hours)

03...45...00...07:36 AM......Crew departs O&C building
03...15...00...08:06 AM......Crew ingress
02...25...00...08:56 AM......Astronaut comm checks
02...00...00...09:21 AM......Hatch closure
01...30...00...09:51 AM......White room closeout

01...10...00...10:11 AM......Begin 10-minute built-in hold (T-minus 20m)
01...00...00...10:21 AM......NASA test director countdown briefing
01...00...00...10:21 AM......Resume countdown (T-minus 20m)

00...59...00...10:22 AM......Backup flight computer to OPS 1
00...55...00...10:26 AM......KSC area clear to launch

00...49...00...10:32 AM......Begin final built-in hold (T-minus 9m)
00...24...00...10:57 AM......NTD launch status verification
00...09...00...11:17:46 AM...Resume countdown (T-minus 9m)

00...07...30...11:19:16 AM...Orbiter access arm retraction
00...05...00...11:21:46 AM...Launch window opens
00...05...00...11:21:46 AM...Hydraulic power system (APU) start
00...04...55...11:21:51 AM...Terminate LO2 replenish
00...04...00...11:22:46 AM...Purge sequence 4 hydraulic test
00...04...00...11:22:46 AM...IMUs to inertial
00...03...55...11:22:51 AM...Aerosurface profile
00...03...30...11:23:16 AM...Main engine steering test
00...02...55...11:23:51 AM...LO2 tank pressurization
00...02...35...11:24:11 AM...Fuel cells to internal reactants
00...02...30...11:24:16 AM...Clear caution-and-warning memory
00...02...00...11:24:46 AM...Crew closes visors
00...01...57...11:24:49 AM...LH2 tank pressurization
00...00...50...11:25:56 AM...SRB joint heater deactivation
00...00...31...11:26:15 AM...Shuttle GPCs take control of countdown
00...00...21...11:26:25 AM...SRB steering test
00...00...07...11:26:39 AM...Main engine start (T-6.6 seconds)
00...00...00...11:26:46 AM...SRB ignition (LAUNCH)