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Atlantis on the pad
Space shuttle Atlantis is delivered to Kennedy Space Center's launch pad 39B on August 2 to begin final preparations for blastoff on the STS-115 mission to resume construction of the International Space Station.

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Atlantis rollout begins
Just after 1 a.m. local time August 2, the crawler-transporter began the slow move out of the Vehicle Assembly Building carrying space shuttle Atlantis toward the launch pad.

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Atlantis on the move
Space shuttle Atlantis is transported to the cavernous Vehicle Assembly Building where the ship will be mated to the external fuel tank and twin solid rocket boosters for a late-August liftoff.

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Clocks begin ticking for Wednesday's blastoff
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: September 3, 2006


Atlantis is scheduled for launch Wednesday from pad 39B. Credit: Ben Cooper/Spaceflight Now
 
With little fanfare, NASA restarted the shuttle Atlantis' countdown today for blastoff Wednesday on a long-awaited mission to restart space station assembly.

The countdown began at 8 a.m. for a launch try Wednesday at 12:29 p.m., a week and a half behind schedule because of a launch pad lightning strike Aug. 25, which prevented an Aug. 27 launch, and then tropical storm/hurricane Ernesto.

As with Atlantis' first launch try, the 76-hour 23-minute countdown began six hours earlier than normal. That will give engineers a better chance of getting the shuttle's fuel cell system loaded with liquid oxygen and hyrogen Monday morning before any afternoon storms can develop and provide additional time to handle unexpected problems.

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Additional coverage for subscribers:
VIDEO: BIOGRAPHY MOVIE ON THE SIX ASTRONAUTS PLAY
VIDEO: SHORT MOVIE PREVIEW OF ATLANTIS' MISSION PLAY
VIDEO: OUTLOOK ON UPCOMING STATION ASSEMBLY FLIGHTS PLAY
MORE: STS-115 VIDEO COVERAGE
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The latest Air Force weather forecast calls for an 80 percent chance of acceptable weather Wednesday, dropping to 70 percent "go" Thursday and Friday.

"Our primary concerns for launch are cumulus clouds within 10 nautical miles of (launch) complex 39B and isolated showers within 20 nautical miles of the Shuttle Landing Facility," according to the forecast.

"The probability of KSC weather prohibiting launch increases slightly the following two days due to a frontal boundary approaching Central Florida from the northwest. This boundary with strong upper level winds from the west may cause anvil clouds from thunderstorms in the Gulf of Mexico and along the west coast of Florida to (move) east toward KSC."

NASA safety rules forbid a launch if electrically active anvil clouds move within a few miles of the launch site.

A detailed countdown chart is posted here.

Here is a summary of countdown highlights (in EDT):


Sunday  09/03/06

08:00:00 AM       Countdown begins

Monday  09/04/06

12:00:00 AM       ** Begin 4-hour built-in hold
04:00:00 AM       ** Resume countdown
05:30:00 AM       Fuel cell oxygen loading begins
08:00:00 AM       Fuel cell oxygen load complete
08:00:00 AM       Fuel cell hydrogen loading begins
10:30:00 AM       Fuel cell hydrogen load complete
12:00:00 PM       ** Begin 10-hour built-in hold
10:00:00 PM       ** Countdown resumes (now in synch with standard count)

Tuesday  09/05/06

06:00:00 AM       ** Begin 13-hour 33-minute hold
03:00:00 PM       ** Rotating service structure to park position
07:33:00 PM       ** Resume countdown
08:43:00 PM       Fuel cell activation
10:33:00 PM       Final fueling preps; launch area clear

Wednesday  09/06/06

12:33:00 AM       ** Begin 2-hour built-in hold (T-minus 6 hours)
01:03:00 AM       ** External tank ready for fueling
01:23:00 AM       ** Mission management team go/no-go tanking meeting
02:33:00 AM       ** Resume countdown (T-minus 6 hours)
02:33:00 AM       Liquid oxygen/hydrogen transfer line chilldown
02:43:00 AM       Liquid hydrogen (LH2) slow fill
03:03:00 AM       Liquid oxygen (LO2) slow fill
03:23:00 AM       LO2 fast fill
03:33:00 AM       LH2 fast fill
05:33:00 AM       ** Begin 3-hour built-in hold (T-minus 3 hours)
05:33:00 AM       ** External tank in stable replenish mode
07:59:00 AM       ** Astronaut weather briefing
08:09:00 AM       ** Astronauts don pressure suits
08:33:00 AM       Resume countdown (T-minus 3 hours)
08:39:00 AM       Astronauts depart crew quarters
09:09:00 AM       Crew straps in
09:58:00 AM       Astronaut communications checks
10:23:00 AM       Hatch closed
11:13:00 AM       ** Begin 10-minute built-in hold (T-minus 20m)
11:23:00 AM       ** Resume countdown (T-minus 20m)
11:24:00 AM       Backup flight computer loads OPS 1 software
11:34:00 AM       ** Begin final built-in hold (T-minus 9m)
11:44:49 AM       ** NASA test director launch status verification
12:19:49 PM       ** Resume countdown (T-minus 9m)
12:23:49 PM       Hydraulic power system (APU) start
12:25:54 PM       LO2 tank pressurization
12:26:52 PM       LH2 tank pressurization
12:28:18 PM       Shuttle computers take control of countdown
12:28:49 PM       Launch
If Atlantis is delayed Wednesday, the crew will have two more launch opportunities before the current September launch window closes: at 12:03:07 p.m. Thursday and at 11:40:35 a.m. Friday. After that, the flight would be delayed to late October unless NASA relaxes a self-imposed requirement to launch Atlantis in daylight. NASA managers are in the process of reviewing that rationale.

Spaceflight Now Plus
Additional coverage for subscribers:
VIDEO: CREW ARRIVES IN T-38 TRAINING JETS PLAY
VIDEO: COMMENTS FROM CREW AFTER ARRIVAL PLAY
VIDEO: NEWS BRIEFING ON RETURN TO PAD DIALUP | BROADBAND
VIDEO: ATLANTIS ROLLBACK BEGINS PART 1 | PART 2
VIDEO: OFFICIALS EXPLAIN LIGHTNING SCRUB PLAY
VIDEO: SEE THE LIGHTNING STRIKE AT PAD B PLAY
VIDEO: ANOTHER VIEW OF LIGHTNING STRIKE PLAY


VIDEO: COMPLETE PREVIEW OF ATLANTIS MISSION PLAY
VIDEO: DETAILS OF THE THREE SPACEWALKS PLAY
VIDEO: MEET THE SIX ASTRONAUTS PLAY
MORE: STS-115 VIDEO COVERAGE
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STS-115 patch
The official crew patch for the STS-115 mission of space shuttle Atlantis to resume orbital construction of the International Space Station.
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MISSION INDEX