Tweeters and Atlantis Ready for Launch

(Editor’s Note: Ken Kremer is in Florida for Universe Today covering the upcoming Atlantis launch attempt.)
Space shuttle Atlantis is all fueled up and ready for launch. Liftoff time is slated for 2:28 PM EST Monday. The weather forecast has degraded somewhat to 70 percent acceptable from the prior 90 percent forecast. The only concern is the possibility of low cloud ceilings this afternoon. Skies are overcast here at the KSC press center. All the emergency landing sites are “Green”. The launch team is not working any issues at this time. Among those on site at Kennedy Space Center are about 100 Twitter devotees, who are part of a special NASA “Tweet Up.” They’ve been able to tour different facilities and will be on hand for the launch attempt today.

The “tanking” procedure began with a 10 minute chill down of the pipes at pad 39 A. Valves leading to the bottom of the 154 foot tall External Tank (ET) were cracked open to begin the roughly 3 hour fueling process of cryogenic propellants. Approximately 535,000 gallons of supercold liquid oxygen (LOX, minus 298 deg F) and liquid hydrogen (LH2, minus 423 deg F ) are loaded from storage tanks around the pad to the shuttles mobile launch platform and is nearly complete as of 7 AM. Thereafter the LOX (145,000 gallons) and LH2 (390,000 gallons) are replenished as needed.

The final inspection team will then proceed to pad 39 A to carefully inspect the ET for any signs of ice build-up which could fall off the ET during ascent and potentially damage the shuttle. The cryogenic propellants fuel the orbiters three main engines (SSME’s) during liftoff and ascent for the 8 and a half minute climb to orbit.
This is the 129th Space Shuttle flight, the 31st flight of Atlantis and the last flight of 2009. Only 5 flights remain after STS 129.

The countdown clock began ticking at T minus 6 hours with the start of fueling.

On Sunday, I watched from a mere few hundred meters away as NASA technicians retracted back the Rotating Service Structure (RSS) at Launch Pad 39 A to unveil a gleaming white Space Shuttle Atlantis for her heavenly trek to the International Space Station (ISS). Media numbering perhaps a hundred from around the globe, including many from across Asia, were on hand to witness the event which began at 5:30 PM EST as the sun was setting.

The global nature of the news coverage augers well for interest in the ever expanding number of international science experiments being conducted aboard the station in a peaceful and collaborative manner to unite the nations of the world in this magnificent engineering achievement.

Rollback of the RSS to the parked position was completed at 5:56 PM during the T minus 11 hour hold during the launch countdown. The massive cocoon-like structure is 130 feet tall and provides weather protection and access for technicians to work on the shuttle and cargo in the payload bay. Installation and work on the STS 129 payload had already been completed and the payload bay doors were closed.

The countdown continues smoothly towards an afternoon liftoff at 2:28 PM EST. The STS-129 Space Shuttle Commander is Charles O. Hobaugh (third flight). Pilot is Barry E. Wilmore (first flight). The four Mission Specialists are Leland Melvin (second flight), Randy Bresnik (first flight), Mike Foreman (second flight) and Robert L. Satcher Jr. (first flight).

Watch continuous NASA live launch commentary on NASA TV and the Web

Here is a timeline of events on what to expect for Launch day:
4:30 AM Crew wake up
5 AM Crew breakfast
5:03 Tanking Begins. Chill down propellant transfer lines
5:13 Begin loading the external fuel tank with about 500,000 gallons of cryogenic propellants
5:30 Crew final medical checks
6:03 Liquid Hydrogen “fast fill” begins
7:18 Liquid Hydrogen “topping” begins (gaseous hydrogen vent valve cyclng)
8:03 Complete filling the external tank with its flight load of liquid hydrogen and liquid oxygen propellants
Final Inspection Team proceeds to launch pad
8:30 Ascent team on console in Mission Control
9:30 Launch coverage begins on NASA TV
10:05 Astronauts don flight suits
10:38 Crew departs Operations and Checkout Building for pad 39 A
Complete closeout preparations in the White Room
Check cockpit switch configurations
11:08 Flight crew begins to board Atlantis
Astronauts perform air-to-ground voice checks with Launch and Mission Control
12:13 PM Begin to close Atlantis’ crew hatch
Perform hatch seal and cabin leak checks
12:53 Complete White Room closeout
Closeout crew moves to fallback area
1:13 Enter 10-minute hold at T-20 minutes
NASA test director conducts final launch team briefings
1:23 Resume countdown at T-20 minutes
Transition the orbiter’s onboard computers to launch configuration
Start fuel cell thermal conditioning
Close orbiter cabin vent valves
Transition backup flight system to launch configuration
1:34 Countdown enters estimated 45-minute hold at T-9 minutes
Launch director, Mission Management Team and NASA test director conduct final polls for “go/no go” to launch
2:19 Resume countdown at T-9 minutes
Start automatic ground launch sequencer (T-9 minutes)
Retract orbiter crew access arm (T-7:30)
Start APU recorders (T-6:15)
Start auxiliary power units (T-5)
Terminate liquid oxygen replenish (T-4:55)
Start orbiter aerosurface profile test (T-3:55)
Start main engine gimbal profile test (T-3:30)
Pressurize liquid oxygen tank (T-2:55)
Begin retracting the gaseous oxygen vent arm (T-2:50)
Fuel cells to internal reactants (T-2:35)
Pressurize liquid hydrogen tank (T-1:57)
Deactivate bi-pod heaters (T-1:52)
Deactivate solid rocket booster joint heaters (T-0:50 seconds)
Orbiter transfers from ground to internal power (T-0:50 seconds)
Ground launch sequencer go for auto sequence start (T-0:31 seconds)
Booster gimbal profile (T-0:21 seconds)
Ignition of three space shuttle main engines (T-6.6 seconds)
Booster ignition and liftoff (T-0)

2:28:04 PM Preferred launch time

Read my earlier KSC reports on launch attempts for Atlantis and Atlas here:

Clock Ticking for Shuttle Atlantis on Critical Resupply Mission

Atlas Launch halted by ORCA; Shuttle Atlantis Next in Line

Ken Kremer’s website