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Orbiter: Endeavour
Mission: STS-134
Payload: AMS
Launch: May 16, 2011
Time: 8:56 a.m. EDT
Site: Pad 39A, Kennedy Space Center
Landing: June 1 @ approx. 2:32 a.m. EDT
Site: KSC's Shuttle Landing Facility

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Cdr Mark Kelly

Pilot Greg Johnson

MS 1 Mike Fincke

MS 2 Roberto Vittori

MS 3 Drew Feustel

MS 4 Greg Chamitoff




Mission Status Center

By Justin Ray

Live coverage of space shuttle Endeavour's STS-134 mission to the International Space Station. Text updates will appear automatically; there is no need to reload the page. Follow us on Twitter.

MONDAY, MAY 16, 2011
1956 GMT (3:56 p.m. EDT)
T+plus 7 hours. Flight controllers in Houston have bid goodnight to commander Mark Kelly and crew. After successfully getting into orbit, the astronauts quickly went to work transforming their rocket into a spacecraft by opening the payload bay doors and activating the myriad of systems. They've already completed the first in the series of trajectory maneuvers en route to the space station. The shuttle's robotic arm also got checked out to prepare for tomorrow's post-launch heat shield inspections.

The astronauts heading to bed for an eight-hour sleep period. They'll be awakened for Flight Day 2 at 11:56 p.m. EDT.
1926 GMT (3:26 p.m. EDT)
T+plus 6 hours, 30 minutes. The crew is wrapping up its first work shift in orbit. Things have progressed very well for the astronauts following an on-time blastoff this morning at 8:56 a.m. EDT. They are in their pre-sleep period now before bedtime.
1801 GMT (2:01 p.m. EDT)
T+plus 5 hours, 5 minutes. The astronauts have examined Endeavour's windows and reported to Mission Control there's no launch-related clouding or damage.
1740 GMT (1:40 p.m. EDT)
T+plus 4 hours, 44 minutes. The payload bay survey has been accomplished and Endeavour's robot arm is ready to be powered down for the day. The crew will use the arm extensively tomorrow to perform the standard heat shield inspections.
1717 GMT (1:17 p.m. EDT)
T+plus 4 hours, 21 minutes. Pilot Greg Johnson and flight engineer Roberto Vittori have completed the robotics checkout with no problems to report. Next up will be a survey of the payload bay using the arm's cameras.
1655 GMT (12:55 p.m. EDT)
T+plus 3 hours, 59 minutes. The Alpha Magnetic Spectrometer -- the main cargo being hauled by shuttle Endeavour to the International Space Station -- has been brought to life.

"AMS is in space and activated," mission specialist Mike Fincke reports from Endeavour.

The $2 billion particle physics experiment aims to answer some of the grand questions about how the universe was created, the invisible matter and energy that make up most of the cosmos and the existence of antimatter.

It will be attached to the space station on Thursday.
1645 GMT (12:45 p.m. EDT)
Running two weeks late because of an electrical glitch, the repaired shuttle Endeavour finally blasted off and rocketed into orbit for the last time Monday, putting on a spectacular, if brief, show for several hundred thousand spectators expected for NASA's next-to-last shuttle launch.

Read our full story.
1636 GMT (12:36 p.m. EDT)
T+plus 3 hours, 40 minutes. The Alpha Magnetic Spectrometer is being powered up for the first time since it arrived in orbit aboard the space shuttle Endeavour. Mission specialist Mike Fincke is responsible for the activation work, and he talked about the task during a pre-flight interview:

"I have to really commend the engineers and the scientific teams that have put together, about as plug and play as you can get.

"Once the Alpha Magnetic Spectrometer launches with us in the payload bay, a few minutes after we get into orbit, I have the privilege of opening up a laptop and connecting it, turning it on for the first time in space, and then, when we dock to the International Space Station.

"So we'll take care of it for four or five days aboard Endeavour, and then once we dock with the International Space Station, my colleagues will reach in with the shuttle robot arm, lift it out of the payload, stick it out into space, then the station robot arm will come and grab it and put it on the outboard truss of the International Space Station.

"The station was designed with universal adapters so it has a little claw that grabs, pulls it in, and then electrical and data connectors come right up and connect and it's plug and play, ready to go; you have power and data and that's what made the Alpha Magnetic Spectrometer possible.

"They could not have built a spacecraft, unless it was the space station, large enough to support the power and data needs that the AMS has just to detect all the things that it does, but yet, it's just another payload for the International Space Station which is so big and large and it provides space station even more science for life on planet Earth."
1620 GMT (12:20 p.m. EDT)
T+plus 3 hours, 24 minutes. The astronauts have powered up and extended space shuttle Endeavour's robotic arm for a system checkout.
1549 GMT (11:49 a.m. EDT)
T+plus 2 hours, 53 minutes. Space shuttle Endeavour and crew have completed NC1 engine firing to adjust the orbital path to the International Space Station. The 1-minute course correction maneuver using both Orbital Maneuvering System engines changed the shuttle's velocity by 63.8 miles per hour, boosting the orbit to 205 by 201 statute miles.
1535 GMT (11:35 a.m. EDT)
T+plus 2 hours, 39 minutes. The ascent team of flight controllers led by Richard Jones is handing over to the Orbit 2 team and flight director Paul Dye to oversee the rest of the astronauts' workday. The CAPCOM duties will be handed from Butch Wilmore to Mike Massimino.
1532 GMT (11:32 a.m. EDT)
T+plus 2 hours, 36 minutes. CAPCOM astronaut Butch Wilmore in Mission Control just told the crew that launch video and imagery continues to be analyzed but there's no concerns noted so far.
1452 GMT (10:52 a.m. EDT)
T+plus 116 minutes. The Ku-band system has been activated successfully and live television from the orbiter's crew cabin is being downlinked to the ground.
1438 GMT (10:38 a.m. EDT)
T+plus 102 minutes. The Ku-band antenna is deployed. This is the system used for high-speed communications, television downlink and the rendezvous radar.
1437 GMT (10:37 a.m. EDT)
The latest version of the NASA Television schedule (Rev. A) can be downloaded here.
1432 GMT (10:32 a.m. EDT)
T+plus 96 minutes. Endeavour's antenna for Ku-band high-speed communications is being deployed. Standing by for system activation.
1429 GMT (10:29 a.m. EDT)
T+plus 93 minutes. Go for orbit operations! That's the formal call from Mission Control indicating the shuttle is in good shape following launch and the Endeavour crew can proceed with mission activities.

Both 60-foot-long payload bay doors of shuttle Endeavour have been opened and the radiators activated.

Over the next few hours, the astronauts will busily begin setting up the onboard computer network and downlinking imagery and data gathered during ascent. The crew will be getting out of their launch and entry spacesuits, stowing away the mission specialists' seats and getting some dinner as well. An eight-hour sleep period begins at 3:56 p.m. EDT.
1422 GMT (10:22 a.m. EDT)
Check out our launch photo gallery taken from the Press Site.
1418 GMT (10:18 a.m. EDT)
T+plus 82 minutes. The post-launch news conference is underway at Kennedy Space Center. A couple of small foam losses were seen in the external tank video camera footage during launch but didn't appear to get close to the orbiter.
1414 GMT (10:14 a.m. EDT)
T+plus 78 minutes. Mission Control has voiced a "go" to the crew for payload bay door opening.
1408 GMT (10:08 a.m. EDT)
T+plus 72 minutes. Endeavour is 198 miles over the South Pacific now.
1356 GMT (9:56 a.m. EDT)
T+plus 60 minutes. The crew continues working through its post-launch activities. The next big milestones will be opening up the payload bay doors and deploying the Ku-band communications antenna.
1346 GMT (9:46 a.m. EDT)
T+plus 50 minutes. Endeavour is 150 miles over the Indian Ocean now.
1336 GMT (9:36 a.m. EDT)
T+plus 40 minutes. The twin Orbital Maneuvering System engines on the tail of Endeavour have been fired successfully to propel the shuttle the rest of the way to orbit.
1335 GMT (9:35 a.m. EDT)
T+plus 38 minutes, 30 seconds. Endeavour has begun the maneuvering burn to raise the orbit toward the International Space Station. This will be a 2-minute firing resulting in an orbit of 202 by 141 statute miles.
1329 GMT (9:29 a.m. EDT)
T+plus 33 minutes. Commander Mark Kelly and pilot Greg Johnson are getting Endeavour maneuvered into the proper position for the OMS 2 engine burn to boost the shuttle from its current orbit of 136 by 36 mile statute miles.
1325 GMT (9:25 a.m. EDT)
T+plus 29 minutes. The two flapper doors on the belly of Endeavour are swinging closed to shield the umbilicals that had connected to the external fuel tank.
1323 GMT (9:23 a.m. EDT)
T+plus 27 minutes. Pilot Greg Johnson has powered down the main propulsion system.
1316 GMT (9:16 a.m. EDT)
T+plus 20 minutes. The planned OMS 2 burn will begin at T+plus 37 minutes.
1312 GMT (9:12 a.m. EDT)
T+plus 16 minutes. Endeavour now cruising over the North Atlantic.
1311 GMT (9:11 a.m. EDT)
T+plus 15 minutes. The three Auxiliary Power Units are being shut down by pilot Greg Johnson.
1307 GMT (9:07 a.m. EDT)
Share your thoughts about this morning's launch of the space shuttle Endeavour on our Facebook page!
1306 GMT (9:06 a.m. EDT)
T+plus 10 minutes. Endeavour safely sailed into orbit today on a 16-day journey to the International Space Station to install the Alpha Magnetic Spectrometer experiment that promises to chart a new course in physics research, plus deliver another stockpile of spare parts for supporting the outpost's extended life.
1305 GMT (9:05 a.m. EDT)
T+plus 9 minutes, 30 seconds. It was a nominal MECO. A quick boost from the Orbital Maneuvering System engines is not required to reach the planned preliminary sub-orbital trajectory.
1305 GMT (9:05 a.m. EDT)
T+plus 9 minutes, 15 seconds. Still cameras embedded in Endeavour's umbilical well are taking images of the external tank to document its foam.
1305 GMT (9:05 a.m. EDT)
T+plus 8 minutes, 44 seconds. The emptied external tank has been jettisoned from the belly of space shuttle Endeavour. The tank will fall back into the atmosphere where it will burn up harmlessly.
1304 GMT (9:04 a.m. EDT)
T+plus 8 minutes, 30 seconds. MECO. Main Engine Cutoff confirmed!
1304 GMT (9:04 a.m. EDT)
T+plus 8 minutes, 3 seconds. The main engines are running at 82 percent thrust.
1304 GMT (9:04 a.m. EDT)
T+plus 7 minutes, 45 seconds. The main engines are beginning to throttle down to ensure the shuttle does not experience forces greater than 3 g's as it continues to accelerate prior to engine shutdown.
1304 GMT (9:04 a.m. EDT)
T+plus 7 minutes, 33 seconds. Endeavour is 64 miles in altitude, 630 miles downrange from the launch pad, traveling at 13,500 mph.
1303 GMT (9:03 a.m. EDT)
T+plus 7 minutes. Single engine press. The shuttle can reach orbit on the power from a single main engine should two fail at this point. But all three continue to fire properly.
1302 GMT (9:02 a.m. EDT)
T+plus 6 minutes, 8 seconds. "Press to MECO." Endeavour can now achieve a safe orbit on two engines. All three remain in good shape.
1302 GMT (9:02 a.m. EDT)
T+plus 6 minutes. The shuttle has started rolling to a heads-up position to improve communications with the TDRS satellite network.
1301 GMT (9:01 a.m. EDT)
T+plus 5 minutes, 5 seconds. "Press to ATO". Endeavour can reach an orbit, albeit a low orbit, on two engines should one shut down now. But all three powerplants are still running just fine.
1301 GMT (9:01 a.m. EDT)
T+plus 4 minutes, 40 seconds. Endeavour will be tripling its speed in the next four minutes to reach orbital velocity of nearly 17,500 mph.
1300 GMT (9:00 a.m. EDT)
T+plus 4 minutes, 30 seconds. Endeavour is 63 miles in altitude, 186 miles downrange from the launch pad, traveling over 5,500 mph.
1300 GMT (9:00 a.m. EDT)
T+plus 4 minutes. Negative return. The shuttle has passed the point where Endeavour could turn around and make an emergency landing at Kennedy Space Center in the event of a main engine problem. Landing sites in France and Spain are now available to Endeavour in the unlikely event an abort occurs during the remainder of today's launch.
1259 GMT (8:59 a.m. EDT)
T+plus 3 minutes, 30 seconds. Overseeing today's climb to orbit from the Mission Control Center is ascent flight director Richard Jones. Seated alongside in Houston in direct radio contact with the crew is CAPCOM astronaut Butch Wilmore.
1259 GMT (8:59 a.m. EDT)
T+plus 2 minutes, 50 seconds. Commander Mark Kelly just received the "Two-engine TAL" call from CAPCOM Butch Wilmore in Mission Control. The call means Endeavour can now reach a Transatlantic Abort Landing site if one main engine fails. However, all three engines continue to burn normally.
1259 GMT (8:59 a.m. EDT)
T+plus 2 minutes, 35 seconds. The Orbital Maneuvering System engines have been ignited for an additional kick of thrust during Endeavour's climb uphill.
1259 GMT (8:59 a.m. EDT)
T+plus 2 minutes, 30 seconds. Endeavour is 37 miles in altitude, 50 miles downrange from the launch pad, traveling at 3,200 mph.
1258 GMT (8:58 a.m. EDT)
T+plus 2 minutes, 20 seconds. Guidance is converging as programmed. Endeavour's engine nozzles are swiveling to steer the ship toward a precise point for main engine cutoff about six minutes from now.
1258 GMT (8:58 a.m. EDT)
T+plus 2 minutes, 10 seconds. Jettison of the solid rocket boosters has occurred. The spent boosters will parachute into the Atlantic Ocean for retrieval. Endeavour continues its streak toward space on the power generated by the three liquid-fueled main engines.
1258 GMT (8:58 a.m. EDT)
T+plus 1 minute, 45 seconds. Joining commander Mark Kelly and pilot Greg Johnson on the flight deck are shuttle rookies Mike Fincke and Roberto Vittori, taking their first ride aboard an American spacecraft. Seated down on the flight deck are Drew Feustel and Greg Chamitoff.
1257 GMT (8:57 a.m. EDT)
T+plus 90 seconds. The space shuttle now weighs just half of what it did at liftoff. The solid rocket boosters are burning 11,000 pounds of propellant every second. The main engines are guzzling a half-ton of liquid fuel per second from the external tank.
1257 GMT (8:57 a.m. EDT)
T+plus 87 seconds. Endeavour is 11 miles in altitude, 12 miles downrange from the launch pad, traveling at 1,300 mph.
1257 GMT (8:57 a.m. EDT)
T+plus 70 seconds. Endeavour's three main engines have revved back up to their 104 percent power setting. And Mission Control has given the "go at throttle up" call.
1257 GMT (8:57 a.m. EDT)
T+plus 60 seconds. The Endeavour is flying heads-down, wings-level on a northeasterly trajectory away from the Florida spaceport on its last ascent to space.
1257 GMT (8:57 a.m. EDT)
T+plus 40 seconds. Endeavour's three liquid-fueled main engines are throttling down to their 72 percent power setting to ease the strain on the vehicle during passage through the region of maximum aerodynamic stresses.
1256 GMT (8:56 a.m. EDT)
T+plus 20 seconds. Endeavour has completed its roll maneuver to aim for rendezvous with the International Space Station on Wednesday morning.
1256 GMT (8:56 a.m. EDT)
T+plus 10 seconds. Houston is now controlling as the shuttle clears the tower at Complex 39.
1256:28 GMT (8:56:28 a.m. EDT)
T-minus 10, 9, 8, 7, 6, main engine ignition, 4, 3, 2, 1 and LIFTOFF! Liftoff of Endeavour with the Alpha Magnetic Spectrometer -- probing the mysteries of physics and origins of our universe from the International Space Station!
1255:57 GMT (8:55:57 a.m. EDT)
T-minus 31 seconds. AUTO SEQUENCE START! The handoff has occurred from the Ground Launch Sequencer to the space shuttle. Endeavour's computers now controlling.

In the next few seconds, the solid rocket booster hydraulic steering system will be started, the orbiter's body flap and speed brake moved to their launch positions, the firing chain armed. Main engine ignition begins at T-minus 6.6 seconds.
1255:28 GMT (8:55:28 a.m. EDT)
T-minus 1 minute. Computers are verifying that the main engines are ready for ignition. Sound suppression water system is armed. The system will activate at T-minus 16 seconds to suppress the sound produced at launch. And the residual hydrogen burn ignitors are armed. They will be fired at T-minus 10 seconds to burn off hydrogen gas from beneath the main engine nozzles.

Shortly, the external tank strut heaters will be turned off; Endeavour will transition to internal power; the liquid oxygen and liquid hydrogen outboard fill and drain valves will be closed; the payload bay vent doors will be positioned for the launch; and the gaseous oxygen vent arm will be verified fully retracted.
1254:58 GMT (8:54:58 a.m. EDT)
Now 90 seconds from the final launch of Endeavour.
1254:28 GMT (8:54:28 a.m. EDT)
T-minus 2 minutes. The astronauts are being instructed to close and lock the visors on their launch and entry helmets.

At T-minus 1 minute, 57 seconds the replenishment to the flight load of liquid hydrogen in the external tank will be terminated and tank pressurization will begin.
1253:58 GMT (8:53:58 a.m. EDT)
T-minus 2 minutes, 30 seconds. The external tank liquid oxygen vent valve has been closed and pressurization of the LOX tank has started.

Endeavour's power-producing fuel cells are transferring to internal reactants. The units will begin providing all electricity for the mission beginning at T-50 seconds.

And pilot Greg Johnson has been asked to clear the caution and warning memory system aboard Endeavour. He will verify no unexpected errors in the system.

In the next few seconds, the gaseous oxygen vent hood will be removed from atop the external tank. Verification that the swing arm is fully retracted will be made by the Ground Launch Sequencer at the T-minus 37 second mark.
1253:28 GMT (8:53:28 a.m. EDT)
T-minus 3 minutes. Orbiter steering check is now complete and the main engine nozzles are in their start positions.
1252:58 GMT (8:52:58 a.m. EDT)
T-minus 3 minutes, 30 seconds. The main engine nozzles now being moved through a computer controlled test pattern to demonstrate their readiness to support guidance control during launch.
1252:28 GMT (8:52:28 a.m. EDT)
T-minus 4 minutes. Activation of the APUs is complete. The three units are up and running normally.

And the final helium purge sequence is underway in the main propulsion system. This procedure readies fuel system valves for engine start. In the next few seconds, the aerosurfaces of Endeavour will be run through a pre-planned mobility test to ensure readiness for launch. This is also a dress rehearsal for flight of the orbiter's hydraulic systems.
1251:28 GMT (8:51:28 a.m. EDT)
T-minus 5 minutes and counting. The "go" has been given for Auxiliary Power Unit start. Pilot Greg Johnson is now flipping three switches in Endeavour's cockpit to start each of the three APU's. The units, located in the aft compartment of Endeavour, provide the pressure needed to power the hydraulic systems of the shuttle. The units will be used during the launch and landing phases of the mission for such events as moving the orbiter's aerosurfaces, gimbaling the main engine nozzles and deploying the landing gear.

Over the course of the next minute, the orbiter's heaters will be configured for launch by commander Mark Kelly, the fuel valve heaters on the main engines will be turned off in preparation for engine ignition at T-6.6 seconds and the external tank and solid rocket booster safe and arm devices will be armed.
1250:58 GMT (8:50:58 a.m. EDT)
T-minus 5 minutes, 30 seconds. APU pre-start is complete and the units are ready for activation. The orbiters flight data recorders have gone into the record mode to collect measurements of shuttle systems performance during flight.
1250:28 GMT (8:50:28 a.m. EDT)
T-minus 6 minutes. Pilot Greg Johnson has been asked by the orbiter test conductor to pre-start the orbiter Auxiliary Power Units. This procedure readies the three APU's for their activation after the countdown passes T-minus 5 minutes.
1249:58 GMT (8:49:58 a.m. EDT)
T-minus 6 minutes, 30 seconds and counting.
1248:58 GMT (8:48:58 a.m. EDT)
T-minus 7 minutes, 30 seconds. The Ground Launch Sequencer has started pulling the orbiter access arm away from the crew hatch on the port side of the vehicle. The arm was the passage way for the astronauts to board Endeavour a few hours ago. The arm can be re-extended very quickly should the need arise later in the countdown.
1248:28 GMT (8:48:28 a.m. EDT)
T-minus 8 minutes and counting. Pilot Greg Johnson has flipped the switches in the cockpit of Endeavour to directly connect the three onboard fuel cells with the essential power buses. Also, the stored program commands have been issued to the orbiter for antenna alignment and management during launch.
1247:28 GMT (8:47:28 a.m. EDT)
T-minus 9 minutes and counting! The Ground Launch Sequencer has been initiated. The computer program is located in a console in the Firing Room of the Complex 39 Launch Control Center. The GLS is the master of events through liftoff. During the last 9 minutes of the countdown, the computer will monitor as many as a thousand different systems and measurements to ensure that they do not fall out of any pre-determine red-line limits. At T-minus 31 seconds, the GLS will hand off to the onboard computers of Endeavour to complete their own automatic sequence of events through the final half minute of the countdown.
1246:28 GMT (8:46:28 a.m. EDT)
Now 10 minutes from blastoff.
1245 GMT (8:45 a.m. EDT)
The countdown will resume from the T-minus 9 minute mark at 8:47:28 a.m. EDT.
1243 GMT (8:43 a.m. EDT)
NASA launch director Mike Leinbach has conducted his poll and given approval to resume the countdown for liftoff at 8:56 a.m. EDT!
1242 GMT (8:42 a.m. EDT)
The poll by NASA test director Jeff Spaulding confirms there are no technical issues or constraints standing in the way of launch at 8:56 a.m. EDT. The Range also reports "go" on the local weather. And Mission Control says that weather at the abort landing sites is acceptable.
1240 GMT (8:40 a.m. EDT)
Seven minutes are remaining in this built-in hold. There are no technical issues being worked by the launch team. Final readiness polls will be conducted shortly.

The Spaceflight Meteorology Group based in Houston, which is the group that handles weather at the shuttle landing sites, confirms conditions are observed and forecast "go" at the Kennedy Space Center for Return to Launch Site (RTLS).
1235 GMT (8:35 a.m. EDT)
Powering space shuttle Endeavour throughout its eight-and-a-half minute climb to orbit will be the three main engines built by Pratt & Whitney Rocketdyne. The cryogenic powerplants are fed with liquid hydrogen and liquid oxygen stored in the external fuel tank.

In the engine No. 1 position today is the Block 2-2047 engine now making its 14th launch. STS-91 was its debut flight on Endeavour to the Russian space station Mir and STS-132 was the most recent aboard Atlantis to the International Space Station.

Making its third launch is the Block 2-2060 in the engine No. 2 position. The previous flights included Endeavour's STS-127 and Endeavour's STS-131 mission to the International Space Station.

And Block 2-2045 is engine No. 3 on Endeavour. This powerplant is flying for the 12th time starting with Endeavour's STS-89 to Mir and most recently on Endeavour's STS-131.
1234 GMT (8:34 a.m. EDT)
Weather is "go" across the board.
1231 GMT (8:31 a.m. EDT)
We're now 25 minutes from Endeavour's launch on an eight-and-a-half minute trek to space. At main engine cutoff, Endeavour will be flying on a suborbital trajectory with a high point of 136 statute miles and low point of 36 statute miles, inclined 51.6 degrees to the equator. A half-hour later, the twin orbital maneuvering engines will be fired to place the shuttle into a 202 by 141 statute mile orbit.
1225 GMT (8:25 a.m. EDT)
At launch, the space station will be flying 220 miles above the planet southeast of Halifax, Nova Scotia. Liftoff at 8:56 a.m. EDT is timed to place Endeavour on course to dock with the station two days from now.
1220 GMT (8:20 a.m. EDT)
The reusable solid rocket boosters, built by ATK, provide the primary thrust to propel the space shuttle away from Earth during the initial two minutes of flight. The 11 sections on each booster flying on Endeavour are a mixture of refurbished and brand new hardware. The upper cylinder on the left booster, for example, flew on the third shuttle mission in 1983. And another cylinder on the left-hand booster is flying for the very first time. And there's even a section from Endeavour's maiden launch in 1992 that's now flying on the ship's final voyage.

In all, Endeavour's twin boosters have reused segments and pieces that trace back to 59 previous shuttle launches and 11 ground test-firings.

Detailed history information about Endeavour's two boosters can be seen in this PDF download here.

The boosters will parachute into the Atlantic Ocean where a pair of retrieval ships are standing by to recover the rockets and tow them back to shore.
1215 GMT (8:15 a.m. EDT)
No technical issues are being worked in the countdown and meteorologists remain hopeful that weather will cooperate today.
1210 GMT (8:10 a.m. EDT)
Shuttle Endeavour will be taking her 25th and final spaceflight after 19 years of service to America. The vehicle's rich history (to date) includes 280 days in space, or precisely 6,729 hours, 39 minutes and 44 seconds spent in flight.

The missions have spanned 4,429 orbits of Earth and accumulated 103,149,636 miles.

Endeavour's maiden voyage in May 1992 was a dramatic adventure to rescue the wayward Intelsat 603 telecommunications satellite that required the astronauts to improvise with the first-ever three-man spacewalk to manually grab the spacecraft after attempts using a specially-designed capture bar failed to work. The ship also conducted the first Hubble Space Telescope servicing in 1993, one of the stellar achievements for the space program that installed corrective optics to fix the observatory's flawed vision.

Other trips in the 1990s deployed and retrieved satellites, mapped the Earth with radar and scanned the cosmos with payloads carried in the orbiter's cargo bay. She also visited the Russian space station Mir once.

Then Endeavour opened the International Space Station era by launching the first American piece of the outpost -- the Unity connecting node -- to begin orbital construction in December 1998. Subsequent flights by Endeavour would take up the station's initial solar array power tower, all three sections of Canada's robotics including the arm, mobile transporter and Dextre hands, the Japanese science facility's "attic" and "back porch" for research, and the Tranquility utility room with the Cupola.

This upcoming 12th mission to the International Space Station by Endeavour finishes the American construction efforts, which this ship originally began, by adding the Alpha Magnetic Spectrometer and a final spare parts deck.

Construction of Endeavour started in September 1987 as a replacement vehicle for Challenger. The spaceplane was rolled out of the Palmdale factory in April 1991. She became NASA's fifth and final operational space shuttle with her inaugural launch a year later.

Once retired from service after the STS-134 mission, Endeavour will be safed and readied for museum display in Los Angeles.
1207 GMT (8:07 a.m. EDT)
T-minus 9 minutes and holding. Countdown clocks have gone into the planned 40-minute, 28-second built-in hold. Launch is targeted for 8:56:28 a.m. EDT.
1203 GMT (8:03 a.m. EDT)
The Main Propulsion System helium system has been reconfigured by pilot Greg Johnson. Soon the gaseous nitrogen purge to the aft skirts of the solid rocket boosters will be started.
1202 GMT (8:02 a.m. EDT)
Commander Mark Kelly has enabled the abort steering instrumentation. And pilot Greg Johnson has configured the displays inside Endeavour's cockpit for launch.
1200 GMT (8:00 a.m. EDT)
Mission Control in Houston is loading Endeavour's onboard computers with the proper guidance parameters based on the projected launch time.
1159 GMT (7:59 a.m. EDT)
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1156 GMT (7:56 a.m. EDT)
T-minus 20 minutes and counting. The countdown has resumed after a 10-minute hold. Clocks will tick down for the next 11 minutes to T-minus 9 minutes where the final planned hold is scheduled to occur. The hold length will be adjusted to synch up with today's preferred launch time of 8:56 a.m. EDT.

Endeavour's onboard computers are now transitioning to the Major Mode-101 program, the primary ascent software. Also, engineers are dumping the Primary Avionics Software System (PASS) onboard computers. The data that is dumped from each of PASS computers is compared to verify that the proper software is loaded aboard for launch.
1152 GMT (7:52 a.m. EDT)
The official launch window based on radar tracking of the space station's orbit begins at 8:55:42 a.m. and extends to 9:01:29 a.m. EDT for Endeavour to rendezvous with the station on Flight Day 3.

The preferred launch time is 8:56:28 a.m. EDT.
1146 GMT (7:46 a.m. EDT)
T-minus 20 minutes and holding. The countdown has paused for a 10-minute built-in hold. Launch is scheduled for 8:56 a.m. EDT.

During this built-in hold, all computer programs in Firing Room 4 of the Complex 39 Launch Control Center will be verified to ensure that the proper programs are available for the countdown; the landing convoy status will be verified and the landing sites will be checked to support an abort landing during launch today; the Inertial Measurement Unit preflight alignment will be verified completed; and preparations are made to transition the orbiter onboard computers to Major Mode 101 upon coming out of the hold. This configures the computer memory to a terminal countdown configuration.
1145 GMT (7:45 a.m. EDT)
The closeout crew is driving away from the pad.
1142 GMT (7:42 a.m. EDT)
Former space shuttle commander Rick Sturckow is flying weather reconnaissance around the Cape. He's reporting his most recent dive into Runway 15 had good weather conditions for landing.
1140 GMT (7:40 a.m. EDT)
Commander Mark Kelly is pressurizing the gaseous nitrogen system for Endeavour's Orbital Maneuvering System engines and pilot Greg Johnson activated the gaseous nitrogen supply for the orbiter's Auxiliary Power Units' water spray boilers.
1137 GMT (7:37 a.m. EDT)
The work to seal the shuttle's crew compartment hatch for flight is complete. And the closeout team that assisted the astronauts into Endeavour today has stowed equipment in the White Room before leaving the launch pad now.
1134 GMT (7:34 a.m. EDT)
The latest forecast for launch time is expected to include scattered clouds at 3,500 feet and 5,200 feet, good visibility, west-northwesterly winds from a direction of 250 degrees of 10 knots gusting to 15 knots and a temperature of 70 degrees.
1128 GMT (7:28 a.m. EDT)
The ground pyrotechnic initiator controllers (PICs) are scheduled to be powered up around this time in the countdown. They are used to fire the solid rocket hold-down posts, liquid oxygen and liquid hydrogen tail service mast and external tank vent arm system pyros at liftoff and the space shuttle main engine hydrogen gas burn system prior to engine ignition.

The shuttle's two Master Events Controllers are being tested. They relay the commands from the shuttle's computers to ignite, and then separate the boosters and external tank during launch.
1125 GMT (7:25 a.m. EDT)
Mainline activation of the Ground Launch Sequencer has been completed. This is the master computer program that will run the final nine minutes of the countdown.
1122 GMT (7:22 a.m. EDT)
At least one of the three Transoceanic Abort Landing sites in Europe must have acceptable weather for the shuttle in case Endeavour must make an emergency landing during launch today. The outlook calls for thunderstorms at Moron runway in Spain and high winds at the Istres landing site France. But Zaragoza in Spain looks good.
1118 GMT (7:19 a.m. EDT)
The official launch weather forecast continues to be 70 percent favorable.
1114 GMT (7:14 a.m. EDT)
Skies are looking to be overcast now as this band of cloudiness rolls in.
1111 GMT (7:11 a.m. EDT)
Repairs have been implemented on this very minor tile damage.
1106 GMT (7:06 a.m. EDT)
The orbiter closeout crew is retrieving the tile repair kit from their truck to touch up the chip.
1104 GMT (7:04 a.m. EDT)
This tile issue today appears to be the black coating has chipped away and exposed the white underlying material around the crew module hatch.
1101 GMT (7:01 a.m. EDT)
The last shuttle mission on Discovery also encountered a chipped tile around the hatch when the closeout crew was buttoning up the shuttle.
1059 GMT (6:59 a.m. EDT)
The closeout crew is reporting some tile damage that engineers are beginning to discuss.
1052 GMT (6:52 a.m. EDT)
Endeavour's hatch has been closed and locked.
1045 GMT (6:45 a.m. EDT)
The orbiter closeout team at the launch pad is shutting Endeavour's crew module hatch for flight.
1042 GMT (6:42 a.m. EDT)
In a pre-flight interview, Endeavour flight engineer and European astronaut Roberto Vittori talked about the risks of human spaceflight:

"I link the word 'risk' with 'probability.' There is a probability of something that could go wrong in anything that you do in life I do not necessarily concentrate on the risk associated with spaceflight, especially because living with NASA, working with NASA, I see that there is a systematic approach to protect the safety of spaceflights and I would consider, I would incline to consider this incredible effort of the NASA community as reducing the risk associated with spaceflight to the minimum possible.

"I feel perfectly at ease in getting ready to climb on the rockets of the shuttle and fly to the International Space Station with my crew."
1037 GMT (6:37 a.m. EDT)
The astronauts are completing a series of radio communication checks with ground controllers.
1030 GMT (6:30 a.m. EDT)
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1023 GMT (6:23 a.m. EDT)
The final Endeavour astronaut has boarded the shuttle today. Roberto Vittori just entered the hatch to sit on the flight deck's aft-center seat as mission specialist No. 2 and flight engineer.

The European Space Agency astronaut representing Italy holds master degrees in aeronautical sciences from the University of Naples and physics from the University of Perugia. He is a colonel in the Italian Air Force with nearly 2,500 hours in over 40 different aircraft.

He has visited the International Space Station twice aboard Russian Soyuz spacecraft in 2002 and 2005.

Read his NASA biography here and Spaceflight Now+Plus subscribers can watch an extended pre-launch interview.
1020 GMT (6:20 a.m. EDT)
As the sun begins to rise, we can see the low clouds to the west that are beginning to move our way.
1008 GMT (6:08 a.m. EDT)
Air Force Col. Mike Fincke is poised to break the U.S. space endurance record during Endeavour's flight by eclipsing the current 377-day cumulative mark held by Peggy Whitson.

But after spending two tours of duty on the International Space Station using Russian Soyuz capsules for transportion, Fincke is ingressing the flight deck's aft-right seat for his very first space shuttle voyage as Endeavour's mission specialist No. 1 and spacewalker.

The native of Pittsburgh holds master degrees in aeronautics and astronautics from Stanford and planetary geology from the University of Houston. In the Air Force, he was a test engineer and logged 1,000 flight hours in more than 30 different aircraft.

His first trip to the space station came in 2004 as the flight engineer on Expedition 9 and he followed that with the 2009 mission as commander of Expedition 18, accumulating 366 days of spaceflight and six Russian-based spacewalks.

Read his NASA biography here and Spaceflight Now+Plus subscribers can watch an extended pre-launch interview.
1006 GMT (6:06 a.m. EDT)
Now passing the T-minus 2 hour mark in the countdown. A pair of built-in holds are planned at T-minus 20 minutes and T-minus 9 minutes, leading toward the 8:56 a.m. T-0 time.
0958 GMT (5:58 a.m. EDT)
Previous long-duration resident of the International Space Station, Greg Chamitoff, serves as Endeavour's mission specialist No. 4 and another of the spacewalkers on the flight. He just entered the orbiter's hatch to take the right-hand seat on the middeck.

Born in Montreal, Canada, he earned degrees from CalPoly and Caltech and has a Ph.D. in aeronautics and astronautics from MIT.

His station voyage as flight engineer and science officer on the Expedition 17 and 18 crews in 2008 started by launching on Endeavour's STS-124 mission and returning to Earth some 183 days later on Endeavour's STS-126 flight.

Read his NASA biography here and Spaceflight Now+Plus subscribers can watch an extended pre-launch interview.
0951 GMT (5:51 a.m. EDT)
Endeavour pilot Greg Johnson is making his way to the flight deck's front-right seat right now for his second spaceflight aboard this particular spacecraft.

The retired Air Force colonel has combat experience from Operation Desert Storm and Operation Southern Watch, plus flight test credentials and over 4,000 flight hours in more than 40 different aircraft.

He arrived at NASA in 1998 and flew on the Endeavour mission in 2008 that delivered Japan's first module and constructed Canada's Dextre handyman robot.

Read his NASA biography here and Spaceflight Now+Plus subscribers can watch an extended pre-launch interview.
0940 GMT (5:40 a.m. EDT)
Drew Feustel went to the Hubble Space Telescope on his previous spaceflight in 2009 and conducted three spacewalks are part of rejuvenating the observatory one last time.

For this shuttle flight to the International Space Station, Feustel will be mission specialist No. 3, the lead spacewalker and ride uphill in the middeck's left-hand seat.

Raised in Lake Orion, Michigan, he earned a Ph.D. in geological sciences from Queen's University in Ontario, Canada, and worked as a geophysicist for Exxon Mobil before becoming an astronaut.

Read his NASA biography here and Spaceflight Now+Plus subscribers can watch an extended pre-launch interview.
0938 GMT (5:38 a.m. EDT)
Commander Mark Kelly is the first astronaut to board the shuttle today, taking the forward-left seat on the flight deck.

The 47-year-old Navy captain from Orange, New Jersey, has 5,000 flight hours in more than 50 different aircraft and logged over 375 carrier landings, plus performed 39 combat missions in Operation Desert Storm.

A veteran of three previous space shuttle missions, Kelly initially flew as pilot on the STS-108 logistics servicing to the International Space Station in 2001 and Endeavour's STS-121 test flight in 2006. His first command came in 2008 as Endeavour's skipper on STS-124 that launched the Japanese laboratory module to the space station.

Read his NASA biography here and Spaceflight Now+Plus subscribers can watch an extended pre-launch interview.
0931 GMT (5:31 a.m. EDT)
The astronauts are taking a few moments to gaze up at their spacecraft from the pad surface before ascending the tower.
0929 GMT (5:29 a.m. EDT)
Endeavour's crew has arrived at launch pad 39A. The AstroVan came to a stop on the pad surface near the Fixed Service Structure tower elevator that will take the six-person crew to the 195-foot level to begin boarding the shuttle.
0922 GMT (5:22 a.m. EDT)
The AstroVan is passing the 52-story Vehicle Assembly Building where Endeavour was attached to its external tank and solid rocket boosters and the adjacent Launch Control Center.

The Press Site is located across the street, and reporters went outside to watch the passing convoy. This is a launch day tradition to say farewell and good luck to the astronaut crews.
0912 GMT (5:12 a.m. EDT)
HERE COMES THE CREW. Space shuttle Endeavour's six veteran astronauts have departed Kennedy Space Center's crew quarters building for today's launch into Earth orbit.

Commander Mark Kelly, pilot Greg Johnson, flight engineer Roberto Vittori and spacewalkers Drew Feustel, Mike Fincke and Greg Chamitoff will ride the AstroVan to pad 39A on the edge of the Atlantic Ocean where they will climb aboard the orbiter this afternoon.
0910 GMT (5:10 a.m. EDT)
The astronauts are leaving the suitup room and heading down the hallway to board the elevator that will take them down to the AstroVan parked outside the Operations & Checkout Building in KSC's Industrial Area.
0906 GMT (5:06 a.m. EDT)
T-minus 3 hours and counting. The countdown clocks are ticking again after the planned two-and-a-half hour built-in hold. Clocks will proceed to T-minus 20 minutes when the next hold is scheduled. A final hold occurs at the T-minus 9 minute mark to synch up with the 8:56:28 a.m. EDT launch time.
0905 GMT (5:05 a.m. EDT)
The final inspection team is departing the launch pad after its observations of the shuttle vehicle.
0849 GMT (4:49 a.m. EDT)
Mission specialist Mike Fincke just tweeted a photo of his pre-launch meal and an image of himself before suitup and then after suitup
0841 GMT (4:41 a.m. EDT)
Space shuttle Endeavour's astronauts are donning their day-glow orange launch and entry pressure spacesuits. After final adjustments and pressure checks, the astronauts will depart the suitup room and take the elevator down to the ground level of the Operations and Checkout Building to board the AstroVan for the trip to launch pad 39A at 5:11 a.m.
0831 GMT (4:31 a.m. EDT)
Our launch webcast with Miles O'Brien, David Waters and space station commander Leroy Chiao is streaming live on this page.
0825 GMT (4:25 a.m. EDT)
The latest weather forecast for the Kennedy Space Center and Transoceanic Abort Landing sites in Europe continues to look good this morning. There's no real concerns at the current time.
0820 GMT (4:20 a.m. EDT)
Mission specialist Mike Fincke just tweeted: "Dear God, please bless our crew. Help us in our mission and to return safely home. Please help me not to mess anything up."
0815 GMT (4:15 a.m. EDT)
In a pre-flight interview, Endeavour mission specialist Mike Fincke talked about the past and future of human spaceflight:

"Well, I take a long view of what we've done so far and where we're going. I firmly believe that human beings will not stay long on planet Earth and that there's a whole universe out there to explore, and we're going to send people back to the moon, we're going to have colonies on the moon, we're going to go to Mars and, boy, I can't wait to learn some day that we have human beings in other solar systems.

"It might be pie in the sky but, you know, our population is already six billion on this planet and there's just going to be a lot of demand for more room and we've got the technology and we have the resources and there's so many amazing resources out there in space -- on the moon, for example -- that haven't been tapped and that will not hurt the environment and won't hurt other people. I mean, it's going to be a major change in what human beings are doing.

"So a really small piece of that story is going to be Endeavour's last mission, but, the Space Shuttle Program, I think, will definitely be remembered for the amazing things that it has done. Having come from a capsule background...space shuttle was just absolutely amazing in terms of what it can do, how many people it can take up, how much cargo, and the complexity that it had especially for its time, fly by wire systems, all these things we take for granted today, you know, 30 or 40 years later in our airplanes. Well, the space shuttle was among the first to do it and it did well.

"Space shuttle also built humanity's first outpost to the stars, the International Space Station. That's a great legacy and everything that we've learned along the way, all the technology, all of the science that we've been able to bring in in these past years with the space shuttle, I think, is going to be remembered very nicely in the history books."
0800 GMT (4:00 a.m. EDT)
The Final Inspection Team is out at the launch pad to scan the vehicle for any ice or debris concerns following fueling operations. The team is responsible for checking the shuttle and launch pad one last time prior to liftoff.

The team is comprised of engineers and safety officials from NASA, United Space Alliance and tank-builder Lockheed Martin. At the conclusion of their two-hour tour-of-duty, the team will have walked up and down the entire fixed service structure and mobile launcher platform.

The team is on the lookout for any abnormal ice or frost build-up on the vehicle and integrity of the external tank foam insulation.

The team uses a portable infrared scanner that gathers temperature measurements on the surface area of the shuttle and can spot leaks. The scanner will be used to obtain temperature data on the external tank, solid rocket boosters, space shuttle orbiter, main engines and launch pad structures. The scanner can also spot leaks of the cryogenic propellants, and due to its ability to detect distinct temperature differences, can spot any dangerous hydrogen fuel that is burning.

The team wears the highly visible day-glow orange coveralls that are anti-static and flame resistant. Each member also has a self-contained emergency breathing unit that holds about 10 minutes of air.
0745 GMT (3:45 a.m. EDT)
The heaters on the Auxiliary Power Units are working well in today's countdown, now that Endeavour's aft compartment is chilled down.
0740 GMT (3:40 a.m. EDT)
The countdown remains on schedule and free of any problems for space shuttle Endeavour this morning. And the weather is looking good as well.

Recent activities in the countdown have included calibrations of the orbiter's inertial measurement units, powering up Endeavour's navigation systems, the pre-flight alignment of ground station antennas with the launch pad and communications checks with the Eastern Range.
0730 GMT (3:30 a.m. EDT)
Here is a timeline of major events through the remainder of today's countdown:
HH...MM...SS...EDT...........EVENT

05...26...00...03:30 AM......NASA TV launch coverage begins
04...25...00...04:31 AM......Final crew weather briefing
04...15...00...04:41 AM......Crew suit up begins
03...50...00...05:06 AM......Resume countdown (T-3 hours)

03...45...00...05:11 AM......Crew departs O&C building
03...15...00...05:41 AM......Crew ingress
02...25...00...06:31 AM......Astronaut comm checks
02...00...00...06:56 AM......Hatch closure
01...30...00...07:26 AM......White room closeout

01...10...00...07:46 AM......Begin 10-minute hold
01...00...00...07:56 AM......NASA test director briefing
01...00...00...07:56 AM......Resume countdown (T-20mins)

00...59...00...07:57 AM......Backup flight computer to OPS 1
00...55...00...08:01 AM......KSC area clear to launch

00...49...00...08:07 AM......Begin final built-in hold (T-9m)
00...24...00...08:32 AM......NTD launch status verification
00...09...00...08:47:28 AM...Resume countdown (T-9mins)

00...07...30...08:48:58 AM...Orbiter access arm retraction
00...05...00...08:51:28 AM...Hydraulic power system start
00...04...55...08:51:33 AM...Terminate LO2 replenish
00...04...00...08:52:28 AM...Purge sequence 4 hydraulic test
00...04...00...08:52:28 AM...IMUs to inertial
00...03...55...08:52:33 AM...Aerosurface profile
00...03...30...08:52:58 AM...Main engine steering test
00...02...55...08:53:33 AM...LO2 tank pressurization
00...02...35...08:53:53 AM...Fuel cells to internal reactants
00...02...30...08:53:58 AM...Clear caution-and-warning memory
00...02...00...08:54:28 AM...Crew closes visors
00...01...57...08:54:31 AM...LH2 tank pressurization
00...00...50...08:55:38 AM...SRB joint heater deactivation
00...00...31...08:55:57 AM...Shuttle takes countdown control
00...00...21...08:56:07 AM...SRB steering test
00...00...07...08:56:21 AM...Main engine start (T-6.6secs)
00...00...00...08:56:28 AM...SRB ignition (LAUNCH)
0720 GMT (3:20 a.m. EDT)
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0710 GMT (3:10 a.m. EDT)
Mission specialist Mike Fincke just tweeted: "Took my last shower for a a few weeks. The flight docs gave a good look-over. My only issue: too much boyish enthusiasm. (no known cure)"
0700 GMT (3:00 a.m. EDT)
"Really smooth tanking, no issues to report," says Charlie Blackwell-Thompson, NASA test director. "Really a good job by the team, and the vehicle and tank performed as we expected."
0645 GMT (2:45 a.m. EDT)
With the hazardous tanking operation now completed, the Orbiter Closeout Crew and Final Inspection Team have been dispatched to the pad to perform their jobs. The closeout crew will ready Endeavour's crew module for the astronauts' ingress in a couple of hours; and the inspection team will give the entire vehicle a check for any ice formation following fueling.
0638 GMT (2:38 a.m. EDT)
TANK FULL. Liquid oxygen has entered stable replenishment mode, officially completing today's three-hour external tank filling process.

For those of you keeping score at home, fueling began at 11:36 p.m. and concluded at 2:36 a.m. EDT.
0636 GMT (2:36 a.m. EDT)
T-minus 3 hours and holding. Clocks have entered a planned two-hour, 30-minute built-in hold. Additional pauses are scheduled at the T-minus 20 and T-minus 9 minute marks, setting up the countdown for launch at 8:56 a.m. EDT.
0634 GMT (2:34 a.m. EDT)
Liquid hydrogen loading has been completed. After reaching the 98 percent level at 1:39 a.m., the topping sequence began. And then the stable replenishment mode was activated at 2:13 a.m. to keep the tank full through the rest of the countdown, replacing the supercold propellant that naturally boils away.
0620 GMT (2:20 a.m. EDT)
Spaceflight Now+Plus subscribers can check out these standard or high-definition video downloads from yesterday's mobile service gantry rollback:

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Additional coverage for subscribers:
VIDEO: BEAUTY SHOTS OF ENDEAVOUR ON THE PAD PLAY | HI-DEF
VIDEO: ROTATING SERVICE STRUCTURE RETRACTED PLAY | HI-DEF
VIDEO: TIME-LAPSE OF SUNDAY'S GANTRY ROLLBACK PLAY | HI-DEF
VIDEO: ANOTHER TOWER TIME-LAPSE FROM PAD CAMERA PLAY
MORE: STS-134 VIDEO ARCHIVE
HDTV: HIGH-DEFINITION COVERAGE
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0555 GMT (1:55 a.m. EDT)
Pilot Greg Johnson just tweeted: "Good Morning!! I am really excited and charged up for this mission! Slept great - enjoyed amazing coffee and breakfast with my crew at 0100."

Mission specialist Mike Fincke also tweeted: "We the STS-134 crew are up and very excited for today's launch."
0530 GMT (1:30 a.m. EDT)
In a pre-flight interview, Endeavour pilot Greg Johnson offered this quick overview of the mission:

"STS-134, we are an International Space Station assembly mission, one of the final ones. We're taking up a very important experiment, the Alpha Magnetic Spectrometer, a science experiment that could change the course of physics. And we're also taking some pieces and parts up to the space station in anticipation of the shuttle retiring, because we only have a few more shuttle flights and so we're taking those parts up in an EXPRESS Logistics Carrier and perching that on top of the space station as well."
0510 GMT (1:10 a.m. EDT)
There are two tanks inside the shuttle's external fuel tank. The liquid oxygen tank occupies the top third of the bullet-shaped tank. It will be filled with 143,000 gallons of liquid oxygen chilled to minus 298 degrees Fahrenheit. The liquid hydrogen tank is contained in the bottom two-thirds of the external tank. It holds 385,000 gallons of liquid hydrogen chilled to minus 423 degrees Fahrenheit.
0431 GMT (12:31 a.m. EDT)
All is going well 55 minutes into the fueling operations for Endeavour. Both liquid oxygen and liquid hydrogen loading have switched to the "fast-fill" mode as fueling of the space shuttle proceeds via remote control at launch pad 39A.

The cryogenics flow from storage spheres at the pad, through feed lines to the mobile launcher platform, into Endeavour's aft compartment and finally into the external fuel tank.
0351 GMT (11:51 p.m. EDT Sun.)
The fueling sequence started with the chilldown of the liquid oxygen system at 11:36 p.m. EDT. The transfer lines on the liquid oxygen side will be chilled down, then the main propulsion system conditioning is completed.

The liquid hydrogen loading has transitioned from the chilldown thermal conditioning process to the "slow-fill" mode. This fills a small fraction of the tank, then the loading switches to "fast-fill" mode. The propellant started flowing into the tank at 11:46 p.m.
0338 GMT (11:38 p.m. EDT Sun.)
FUELING UNDERWAY. Today's filling of space shuttle Endeavour's external tank started on-time at 11:36 p.m. It will take three hours to get the half-million gallons of fuel aboard the shuttle for launch.
0336 GMT (11:36 p.m. EDT Sun.)
T-minus 6 hours and counting. The countdown has resumed ticking after a two-hour hold. The next scheduled built-in hold will occur at T-minus 3 hours.

Fueling should be getting underway shortly. No problems are being worked in the countdown this evening.
0319 GMT (11:19 p.m. EDT Sun.)
The management team's pre-fueling meeting has granted approval to load a half-million gallons of supercold rocket fuel into Endeavour's external tank for launch.
0315 GMT (11:15 p.m. EDT Sun.)
The launch team conducts a safety check on the pyrotechnic circuits to ensure they are in a good configuration before fueling starts. That's the final step before the tanking preps can commence.

The testing is then re-performed after the shuttle gets into cryogenic conditions and before the ice inspection team and orbiter closeout crew head to the pad.
0305 GMT (11:05 p.m. EDT Sun.)
The Mission Management Team meeting is underway.

The weather is just fine at launch pad 39A for fueling Endeavour tonight with just some scattered clouds, westerly winds and a temperature of 69 degrees F. So there's no worries about violating the temperature, lightning or high wind constraints during fueling.

And the latest forecast for launch remains at a 70 percent chance of acceptable weather for Endeavour to fly as scheduled. Crosswinds and the potential for a low-cloud ceilings are the two concerns.

The latest outlook at the 8:56 a.m. EDT launch time is expected to include some scattered clouds at 3,500 feet, good visibility, west-northwesterly winds from a direction of 250 degrees of 10 knots gusting to 15 knots and a temperature of 70 degrees.

The odds of good weather for Tuesday and Wednesday are 40 percent and 80 percent, respectively.
0240 GMT (10:40 p.m. EDT Sun.)
In a pre-flight interview, Endeavour pilot Greg Johnson talked about the risks of spaceflight and why it's worthwhile:

"I think the risk is well worth it because we are an exploring country. We are a leading-edge technology country, and I take my parenting very seriously and I talk to my kids about being the lead dog, and if you're the lead dog, everybody else is looking at the tail end of the lead dog. You want to be the lead dog, not the guys behind. And we've been the lead dog, and the reason we've been the lead dog is because we take those risks, we push technology and exploration forward, and the space program is a perfect example of that, and the technologies and the capabilities that we get from the space program, and the economies ~~ I mean, the economic impact is a little bit intangible, but if you really go back and look at all the various spin-offs and things that we've gotten from the space program and how it's impacted our country and our world, space is that next frontier that we need to explore.

"And so I think it's extremely important to be involved with space and I think that we don't spend enough; I think we should spend much more on our space program than we do these days, but I know times are tight, so any risk to me personally, I think it's well worth it."
0305 GMT (10:05 p.m. EDT Sun.)
Check out this great photo gallery of shuttle Endeavour poised on the launch pad Sunday afternoon!
0236 GMT (9:36 p.m. EDT Sun.)
T-minus 6 hours and holding. The countdown has gone into the scheduled two-hour built-in hold prior to the start of fueling. The Mission Management Team is scheduled to convene its critical pre-fueling meeting around 11 p.m. EDT.

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0030 GMT (8:30 p.m. EDT Sun.)
Hands-on work to configure launch pad 39A has been completed for space shuttle Endeavour's liftoff. The final ground technicians will be clearing the complex shortly in preparation of tonight's hazardous fueling operations that occur via remote control.
SUNDAY, MAY 15, 2011
2300 GMT (7:00 p.m. EDT)
In a pre-flight interview, Endeavour commander Mark Kelly talked about the space shuttle program's retirement and its legacy:

"I've flown on Endeavour before so I'm excited to fly on it again, and my brother's flown on Endeavour.

"The space shuttle was designed to build the space station, and that's why it has this big payload bay, and it never really got to do that for the first 20 years of its life, and now in the last ten it's been critical in building ISS. Without the space shuttle, International Space Station would not be what it is today. We would not have been able to build the space station, so I think it's somewhat fitting that the end of the shuttle era is being finished with the assembly of the space station, and the utilization part for the next 10 or 15 years," he said.

"More people have flown on the space shuttle than any other spacecraft, including Soyuz. The ability to fly seven people into space and have this huge payload bay and an airlock and a robotic arm and to be able to bring payloads home and land on a runway: this is the most capable spacecraft that's ever been built and probably will be built for a long period of time. And, I think Americans should be proud that we've been able to build such a thing and operate it successfully for such a long period of time."
2136 GMT (4:36 p.m. EDT)
T-minus 11 hours and counting. Clocks are running again after this half-day hold. The countdown will proceed to the next pause at T-minus 6 hours tonight.
1930 GMT (3:30 p.m. EDT)
Endeavour's six astronauts spent today studying flight plans, visiting with their families and touring the shuttle at the pad. They also received briefings on orbiter preparations, the payload status and the weather forecast from the ascent team of flight controllers in Houston.

They go to sleep at 4 p.m. EDT and will be awakened for launch day at 12 midnight. They'll have breakfast at 12:30 a.m. and then undergo final medical exams at 1 a.m. Suit up begins around 4:30 a.m. and departure from crew quarters is scheduled for 5:11 a.m. in preparation for blastoff at 8:56 a.m. EDT.
1901 GMT (3:01 p.m. EDT)
Officials say that no unplanned extension of the rotating service gantry will be ordered to fix the nose thruster coverings. The weather forecast is favorable between now and launch time.
1830 GMT (2:30 p.m. EDT)
The official launch window for Monday's shot at getting space shuttle Endeavour into orbit for docking with the International Space Station extends for 5 minutes and 46 seconds.

Based on the latest radar tracking of the space station's orbit and subsequent revision from Mission Control, the single-pane window leading to rendezvous on Flight Day 3 will open at 8:55:42 and lasts until 9:01:28 a.m. EDT.

The targeted liftoff time occurs in the middle of the period at 8:56:28 a.m. EDT. That's the moment when Earth's rotation carries the launch pad into the plane of the station's orbit.

We have updated our countdown timeline and launch events pages with this latest tweak to the liftoff time.

If liftoff slips to Tuesday for some reason, the backup launch opportunity offers a window of 8:28:56 to 8:38:56 a.m. EDT. The preferred launch time would be 8:33:56 a.m. EDT.
1755 GMT (1:55 p.m. EDT)
Several of the protective coverings on Endeavour's nose thrusters have detached in the wind this afternoon. These covers are supposed to keep moisture and debris out of the thruster nozzles until launch. They have flaps that catch the air and pull free from the vehicle during liftoff.
1630 GMT (12:30 p.m. EDT)
On the day before her last launch, the space shuttle Endeavour has been unveiled from the cocoon-like service gantry at Kennedy Space Center's pad 39A for liftoff.

The stage is now set for tomorrow's big show that a half-million spectators around the Space Coast will witness as the spaceship soars majestically into the morning sky.

"When you think about why the people are coming, to experience something that's uniquely American and be able to see one of the last two flights, that gives me a lot of pride," says shuttle launch director Mike Leinbach.

Leinbach oversaw Endeavour's inaugural countdown back in 1992 as the NASA test director. Now he serves as top official in the control center for the orbiter's final flight before entering forced retirement. "The first one was special because it was a brand new vehicle, it was just as beautiful as it could possibly be. I'll just say that the last time I went out to the pad (recently), she still looks awfully good out there. Got a lot of life left in her, but that's not to be."

Technicians will spend the next few hours getting ground equipment configured and secured in preparation for tonight's fueling with supercold rocket propellant. Inside Endeavour's cockpit, meanwhile, support personnel will verify all of the switches are in the correct positions for ascent.

Clocks resume counting at 4:36 p.m. EDT after the half-day hold at T-minus 11 hours. The orbiter's fuel cells will be activated about an hour later, and the hazard area around the pad is scheduled to be cleared of all workers by 9 p.m.

The next planned hold is T-minus 6 hours beginning at 9:36 p.m. EDT. During this two-hour pause of the clocks, the Mission Management Team convenes its pre-fueling meeting around 11 p.m. to review the status of work, the readiness of shuttle systems and the latest weather forecast.

If all goes according to plan, loading of the external tank with propellant will start at 11:36 p.m. EDT. The process should take three hours to complete.

Join us here in the Mission Status Center for live play-by-play updates throughout the overnight. And don't miss our launch webcast with Miles O'Brien, David Waters, former space station commander Leroy Chiao and several special guests that begins at 4:30 a.m. EDT (0830 GMT).

Liftoff time is 8:56 a.m. EDT (1256 GMT) as Endeavour sets sail on her final space voyage.

This is the next-to-last space shuttle mission. The final one goes up sometime in mid-July when Atlantis brings the storied 30-year program to its conclusion.

"It's like breaking up a family. It's tough to deal with. But we're moving on and we're going to fly these last two missions safely and brings the crews home. And then that will be it," Leinbach says.

A reminder that if you will be away from your computer but would like to receive occasional countdown updates, sign up for our Twitter feed to get text messages on your cellphone. U.S. readers can also sign up from their phone by texting "follow spaceflightnow" to 40404. (Standard text messaging charges apply.)

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1625 GMT (12:25 p.m. EDT)
The gantry has arrived in its parking spot for launch.
1612 GMT (12:12 p.m. EDT)
The structure is nearing its launch position.
1604 GMT (12:04 p.m. EDT)
After initially moving at a glacial pace, the speed has picked up and the massive gantry is clear of the shuttle now as it continues to back away.
1553 GMT (11:53 a.m. EDT)
Rollback of the rotating service structure to reveal shuttle Endeavour has started at launch pad 39A. You can watch the tower retraction in our live streaming video.
1530 GMT (11:30 a.m. EDT)
The weather protection panel that reaches outward from the pad's fixed tower to cover Endeavour's port wing remains in place at this hour while technicians use this structure to access a piece of debris for retrieval. The large panel will be retracted and stowed after the gantry is rotated to its launch position.
1522 GMT (11:22 a.m. EDT)
The walkdown inspections at the pad prior to gantry rollback have been completed with no constraints to moving the tower reported.
1420 GMT (10:20 a.m. EDT)
The weather forecast remains unchanged for tomorrow's launch with still a 70 percent chance of acceptable conditions.

Here's the description from the meteorologists:

"An upper-level low is moving into Ohio, and a front associated with the low is moving through the Florida Peninsula. Thunderstorms are passing to the south with anvil clouds stretching northeast over Kennedy Space Center (KSC). Due to the threat of lighting within the anvil clouds, KSC is currently under a Phase I lightning watch. Once the thunderstorms pass to the south and offshore, the threat of lightning will diminish, and weather will be favorable for the noon Rotating Service Structure retract operation.

"The mid- and upper-atmosphere will dry out today, and there is only a slight chance for late afternoon thunderstorms associated with the west coast sea breeze. Winds will decrease into the evening hours, and weather is favorable for tanking tonight.

"By launch time, the weather forecast is generally favorable, but the forecast wind speed and direction causes some concern for a Shuttle Landing Facility (SLF) crosswind violation. There is also just a slight concern for a low-cloud ceiling. Our primary concerns for launch are a SLF crosswind violation and a low cloud ceiling.

"The following day, the upper-level low to the north will still cause concern for cloud cover, a chance for showers, and especially the concern for a SLF crosswind violation. By Wednesday, the weather continues to improve, but there is still potential for a SLF crosswind violation and a low-cloud ceiling."
1400 GMT (10:00 a.m. EDT)
Rollback of the rotating service structure to reveal shuttle Endeavour is coming up. The plan calls for final walkdown inspections of the pad starting at 10 a.m., observers at their duty posts around 11 a.m. and gantry retraction starting at 12 p.m. EDT.
1200 GMT (8:00 a.m. EDT)
Shuttle Endeavour remains poised for blastoff tomorrow at 8:56 a.m. EDT (1256 GMT) on a 16-day flight to deliver an exotic particle physics experiment and a hefty load of spare parts to the International Space Station.

Final tests of the avionics, pneumatics and controllers for the three main engines were conducted overnight. Countdown clocks then entered the lengthy T-minus 11 hour planned hold period at 3 a.m. That built-in hold should last 13 hours and 36 minutes.

Today's chores at launch pad 39A are focused on functional checks of the orbiter's star trackers, activating the inertial measurement units, thoroughly testing the communications network, loading the last items into the crew module, filling of the launch pad's sound suppression system water tank and installing film in pad cameras.

The giant gantry-like rotating service structure is scheduled for retraction from around Endeavour at 12 noon. Fueling of the shuttle's giant external tank begins tonight at 11:36 p.m. EDT.

A reminder that if you will be away from your computer but would like to receive countdown updates, sign up for our Twitter feed to get text messages on your cellphone. U.S. readers can also sign up from their phone by texting "follow spaceflightnow" to 40404. (Standard text messaging charges apply.)

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SATURDAY, MAY 14, 2011
While space shuttle Endeavour takes center stage with her planned blastoff Monday, sistership Atlantis is waiting in the wings to fly the program's final mission sometime in mid-July.

See Atlantis' Mission Status Center.
2300 GMT (7:00 p.m. EDT)
T-minus 19 hours and counting! The countdown has resumed from the scheduled 8-hour-long hold following the fuel cell reactant loading operations today. Clocks will continue ticking until reaching the half-day hold planned at the T-minus 11 hour mark starting at 3 a.m. EDT.
2220 GMT (6:20 p.m. EDT)
With the shuttle Endeavour's countdown proceeding smoothly toward launch Monday, NASA managers carried out a final processing review Saturday and said they were confident the electrical glitch that grounded the ship April 29 has been safely resolved. There are no other technical problems of any significance and forecasters are continuing to predict a 70 percent chance of good weather at launch time Monday.

Read our full story.
2020 GMT (4:20 p.m. EDT)
The Mission Management Team gathered this afternoon for its pre-launch meeting and verified all systems remain "go" for shuttle Endeavour's blastoff Monday at 8:56 a.m. EDT.

"We had a really good meeting today, unanimous consistant from the Mission Management Team to press on with the launch countdown. Everything is in really great shape, really no issues at all," says pre-launch MMT chairman Mike Moses. "We took our time to walk through the issue that caused the launch scrub last time, the APU 1 heater problem to make sure we truly understood our resolution and our fix, that everybody had a chance to see that."

The cryogenic reactants for the space shuttle's electricity-generating fuel cells were successfully loaded aboard Endeavour during a multi-hour operation at pad 39A this morning.

Work performed afterwards adjusted the tank levels, actually removing some of the reactants off the vehicle, to optimize Endeavour's launch weight.

Space shuttle main engine checkouts will be performed tonight while other pad technicians continue work to button up the orbiter and ground support equipment for launch.

Liftoff remains targeted for Monday at 8:56 a.m. EDT (1256 GMT).

"We're not working any issues in the launch countdown, the team is ready to go and hope we have a good liftoff Monday morning for Mark Kelly and his crew," shuttle launch director Mike Leinbach says.

Our live launch webcast hosted by Miles O'Brien, David Waters and former astronaut Leroy Chiao begins Monday at 4:30 a.m. EDT (0830 GMT) from the Kennedy Space Center. Join us for the show!
1955 GMT (3:55 p.m. EDT)
The pre-launch news conference begins at 4 p.m. EDT from the Kennedy Space Center. Watch it live right here!
1915 GMT (3:15 p.m. EDT)
Some stormy weather is moving across Central Florida this afternoon. A lightning warning and heavy rain advisory have been issued for Kennedy Space Center.
1900 GMT (3:00 p.m. EDT)
The odds of acceptable weather for Monday's launch remains posted at 70 percent with crosswinds and low clouds posing only limited concerns.

The outlook from Air Force meteorologists: "An upper-level low is moving into the Eastern U.S., and a surface trough associated with the low is moving through the Eastern Gulf of Mexico. Southwest flow is prevalent throughout the atmosphere over Central Florida, and surface winds are weak enough to allow an afternoon sea breeze to develop. Thunderstorms will develop inland and migrate back toward the East Central Florida Coast. Due to the unstable atmosphere, low level convergence expected with the sea breeze, and the added dynamics of the surface trough, severe weather is possible this afternoon and evening.

"Sunday, the trough should be though Central Florida by the noon Rotating Service Structure retract operations. Weather is favorable also for tanking operations Sunday evening.

"By launch time, the weather forecast is generally favorable, but the forecast wind speed and direction causes some concern for a Shuttle Landing Facility (SLF) crosswind violation. Also, if the timing of the front becomes slower, there is a chance for a low-cloud ceiling.Our primary concerns for launch are a SLF crosswind violation and a low cloud ceiling."

The launch time conditions are expected to include some scattered clouds at 2,500 feet, good visibility, west-southwesterly winds from 250 degrees on the compass at 10 knots gusting to 15 knots and a temperature of 70 degrees.

The forecast for Tuesday's 8:33 a.m. EDT launch opportunity is just 40 percent favorable and Wednesday's 8:08 a.m. shot is 80 percent "go" for weather.

"The upper-level low to the north will still cause concern for cloud cover, a chance for showers, and especially the concern for a SLF crosswind violation. Due to more confidence in this prediction, the probability of Kennedy Space Center (KSC) weather prohibiting launch Tuesday increased to 60%. By Wednesday, the weather continues to improve, but there is still potential for a SLF crosswind violation and a low- cloud ceiling," forecasters say.
1800 GMT (2:00 p.m. EDT)
Endeavour's astronauts checked out their launch and entry spacesuits yesterday, received a briefing on the orbiter ingress plan, visited pad 39A and got some Shuttle Training Aircraft flying time.

The astronauts were awakened at 12 midnight while continuing to shift their sleep patterns to match the overnight work hours of the mission. More Shuttle Training Aircraft and T-38 jet flights were planned today, plus some running on the beach, pre-flight medical exams and time to review the mission files. They will go to sleep at 4 p.m.
1500 GMT (11:00 a.m. EDT)
Countdown clocks have hit the next in the series of pre-planned built-in hold points. This pause at T-minus 19 hours will last through 7 p.m. EDT tonight.
1330 GMT (9:30 a.m. EDT)
The fuel cell storage spheres aboard the space shuttle have been filled with their liquid oxygen and liquid hydrogen reactants this morning. The slight offload and mass adjustments for launch will be accomplished over the next few hours before the umbilical hardware between the pad and Endeavour is disconnected this afternoon.
1230 GMT (8:30 a.m. EDT)
Fuel cell servicing operations are underway this morning as planned. The cryogenic reactants should be all loaded aboard and the work completed by around 2:30 p.m. Also upcoming today is the pre-launch meeting of the Mission Management Team to give final approval to proceed with Monday's liftoff. After the meeting concludes, NASA will hold a news conference around 4 p.m. EDT.
0430 GMT (12:30 a.m. EDT)
The launch pad is being reopened after technicians completed tonight's testing of the shuttle's pyrotechnic initiator controllers and range safety systems. Final preps for the fuel cell loading begins now.
0300 GMT (11:00 p.m. EDT Fri.)
The countdown has entered a planned four-hour hold at the T-minus 27 hour mark. This pause will last through 3 a.m. EDT ahead of the fuel cell servicing work.

Liquid hydrogen and liquid oxygen for Endeavour's electricity-generating fuel cells will be loaded into storage spheres beneath payload bay Saturday morning as standard countdown work continues at pad 39A.

The tankers are expected to be hooked up at 2:30 a.m. and the offload into the shuttle should start around 4:30 a.m. EDT.

The cryogenic reactants are combined by the three onboard fuel cells to produce power and a byproduct of drinking water during the shuttle's mission.

Technicians flow the cryogenics into small tanks aboard the orbiter during a multi-hour operation. Later, they will demate the pad umbilical system used in the loading process and stow that equipment.

Clocks will continue until the next hold point at T-minus 19 hours starting at 11 a.m., which is when the ground team wrap up the fuel cell operations.
0100 GMT (9:00 p.m. EDT Fri.)
Some stormy weather is moving by the spaceport tonight. Flashes from lightning can be seen in the live streaming video from launch pad 39A.
FRIDAY, MAY 13, 2011
1645 GMT (12:45 p.m. EDT)
Engineers restarted the shuttle Endeavour's countdown Friday, setting the stage for a delayed launch Monday on a flight to deliver supplies, spare parts and a $2 billion particle physics detector to the International Space Station. There are no technical problems of any significance at pad 39A and forecasters are predicting a 70 percent chance of good weather.

Read our full story.
1420 GMT (10:20 a.m. EDT)
"We are officially back into launch countdown. We did just pick up the clock a few hours ago and we're counting and working on some of our avionics checkouts right at the beginning of the count as we normally do," says Jeff Spaulding, Endeavour's countdown director.

It was two weeks ago today that a heater power problem on one of shuttle Endeavour's hydraulic units forced officials to scrub the liftoff. The power switching box, associated wiring and the thermostats have been removed and replaced to fix the glitch. Engineers believe an exposed conductor found on one of the thermostats, which also exhibited a current spike during hangar testing last summer, was the culprit. But root cause remains under review.

"I'm really proud of our teams working so hard over the last two weeks. All of the teams here at Kennedy and the other centers have done an outstanding job to get us ready for this launch on a historic and final flight of space shuttle Endeavour."
1100 GMT (7:00 a.m. EDT)
COUNT BEGINS. Countdown clocks at the Kennedy Space Center just began ticking toward Monday's scheduled launch of the shuttle Endeavour on the veteran ship's final trek to space.

The official countdown sequence started at 7 a.m. EDT inside Firing Room 4 of the Complex 39 Launch Control Center. Launch team members had gathered for the "call-to-stations" at 6:30 a.m.

The count commenced from the T-minus 43 hour mark. But a series of pre-planned holds are timed throughout the next few days, leading to the targeted liftoff time of 8:56 a.m. EDT.

Activities planned during the early portion of the countdown for shuttle workers include buttoning up launch pad equipment and removing platforms inside the orbiter's crew module, reviewing flight software stored in Endeavour's mass memory units, loading backup software into the general purpose computers and testing navigation systems.

NASA will host a countdown status and weather briefing today at 10 a.m. EDT. We'll have live streaming video coverage right here on this page.
THURSDAY, MAY 12, 2011
After extensive troubleshooting and repairs to fix an electrical problem with the shuttle Endeavour's hydraulic power system, commander Mark Kelly and his five crewmates flew back to Florida Thursday to prepare for a delayed launch Monday on a long-awaited space station assembly mission, the orbiter's 25th and final flight.

Read our full story.
1730 GMT (1:30 p.m. EDT)
The latest version of the NASA Television schedule for Endeavour's mission can be downloaded here.
1430 GMT (10:30 a.m. EDT)
The weather outlook issued by the launch meteorology team gives a 70 percent chance for Endeavour to fly on Monday morning. The main worry for weather prohibiting launch is the concern for crosswinds at the shuttle's Florida runway that must be available in case an emergency landing is declared just after liftoff.

The specifics call for scattered clouds at 4,000 feet, good visibility, westerly winds of 10 peaking to 15 knots and a temperature of 70 degrees.

"An upper level ridge is over the Gulf of Mexico, and a surface high pressure ridge is over the Eastern U.S. Afternoon heating, the east coast sea breeze, and occasional short-waves moving in from the north continue to cause a chance for afternoon isolated thunderstorms in Central Florida, but mainly inland. By Saturday, the upper-level ridge breaks down as an upper-level trough moves into the Eastern U.S. Mid-level westerly steering flow wind will bring afternoon storms that develop inland toward the east coast," forecasters say.

"Sunday, a trough will move through Central Florida causing the potential for showers and thunderstorms, potentially impacting Rotating Service Structure retract operations. By tanking time Sunday evening, the front will move off to the southeast, and weather will gradually improve.

"By launch time, the weather forecast is generally favorable, but the forecast wind speed and direction causes some concern for a Shuttle Landing Facility (SLF) crosswind violation. Also, if the timing of the front becomes slower, there is a chance for a low-cloud ceiling. Our primary concerns for launch are a SLF crosswind violation with the westerly wind component and a low cloud ceiling if the front delays.

"The following day, another trough may impact the area bringing more cloud cover, a chance for showers, and an increase in the concern for a SLF crosswind violation. By Wednesday, the weather will improve as the trough moves off to the east," forecasters report.

If Endeavour's launch slips to Tuesday for some reason, the odds of acceptable weather dips to 60 percent and then improves to 80 percent on Wednesday.
1335 GMT (9:35 a.m. EDT)
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1315 GMT (9:15 a.m. EDT)
Back at the Kennedy Space Center for the second countdown, the shuttle Endeavour astronauts arrived at the Florida spaceport this morning after spending the recent launch delay undergoing refresher training in Houston.

Commander Mark Kelly, pilot Greg Johnson, flight engineer Roberto Vittori and spacewalkers Drew Feustel, Mike Fincke and Greg Chamitoff are scheduled for blastoff Monday at 8:56 a.m. EDT.

"Thanks for coming out. It's great to be back," Kelly told reporters at the runway. "Exactly four days from now, we all should be strapped in and ready to go. Hopefully the weather will be good. Mike Leinbach (the shuttle launch director) just told us that the vehicle is in great condition. We really appreciate all of the hard work by the team that's worked over the past couple of weeks to get shuttle Endeavour ready."

"I can't think of a more perfect way to spend my birthday than to fly over here with my crew and get ready to fly Endeavour next week," added pilot Greg Johnson, who turns 49 today.

The crew will study flight data files today before going to sleep at 5 p.m. EDT to continue adjusting to the overnight work hours for the mission. After awakening at 1 a.m., Kelly and Johnson plan to fly landing approaches into KSC's runway using Shuttle Training Aircraft at dawn tomorrow.
1305 GMT (9:05 a.m. EDT)
On hand to greet the arriving astronauts as they step off the aircraft is shuttle launch director Mike Leinbach.
1302 GMT (9:02 a.m. EDT)
Welcome to the spaceport! All six Endeavour astronauts have arrived for launch on Monday morning, almost exactly at this time some four days from now.
1301 GMT (9:01 a.m. EDT)
The astronauts are soaring into the Kennedy Space Center's Shuttle Landing Facility, which is the same three-mile-long concrete field where Endeavour will touch down to conclude the upcoming mission.
1258 GMT (8:58 a.m. EDT)
The tower has given the astronauts' jet clearance for touchdown on Runway 15. They are flying together aboard a single Gulfstream aircraft.
1245 GMT (8:45 a.m. EDT)
If you will be away from your computer but would like to receive occasional updates, sign up for our Twitter feed to get text message updates sent to your cellphone. U.S. readers can also sign up from their phone by texting "follow spaceflightnow" to 40404. (Standard text messaging charges apply.)
1240 GMT (8:40 a.m. EDT)
The astronauts have jetted across the Gulf and are over Central Florida now. Their landing is expected shortly.
1230 GMT (8:30 a.m. EDT)
Reporters and photographers are gathered at the runway to cover the astronauts' arrival. You can watch it live with our streaming video coverage when it happens.
1200 GMT (8:00 a.m. EDT)
Endeavour's six astronauts are en route to the Kennedy Space Center today as the launch team prepares to start the countdown for Monday's scheduled blastoff of the next-to-last space shuttle mission.

Meet the astronauts.
1119 GMT (7:19 a.m. EDT)
Commander Mark Kelly, pilot Greg Johnson and mission specialists Mike Fincke, Roberto Vittori, Drew Feustel and Greg Chamitoff have departed Ellington Field outside the Johnson Space Center in Houston for this morning's flight over to the Cape.

Join us here on this page for live streaming video coverage of the astronauts' arrival at 9 a.m. EDT. You'll see the crew step off the aircraft and give a little speech to the reporters gathered at the runway.

Fincke tweeted earlier this morning: "Leaving Crew Quarters in Houston for Ellington Field. Florida and Endeavour here we come..."

And then later: "Our Ellington Send off. Thanks to our awesome training team. And yes, it is still dark. Next stop- Florida!" with this photo.


Read our earlier status center coverage.

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Join Miles O'Brien, David Waters and Leroy Chiao for our live launch webcast from Kennedy Space Center starting Monday at 4:30 a.m. EDT (0830 GMT).
Space models
Expedition 29 Patch

Upcoming mission events:

  • May 12: Crew arrives for launch @ 9 a.m. EDT
  • May 13: Countdown sequence begins @ 7 a.m.
  • May 15: Pad gantry retracted @ 12 noon
  • May 16: LAUNCH @ 8:56 a.m. EDT
  • May 17: Orbiter heat shield inspections
  • May 18: Docking to space station @ 6:15 a.m.
  • May 19: Install AMS on station
  • May 20: Spacewalk No. 1 @ 4 a.m.
  • May 22: Spacewalk No. 2 @ 3 a.m.
  • May 25: Spacewalk No. 3 @ 2:30 a.m.
  • May 27: Spacewalk No. 4 @ 1:30 a.m.
  • May 29: Undocking from station @ 11:53 p.m.
  • May 30: Test re-entry and landing systems
  • June 1: LANDING in Florida @ about 2:32 a.m. EDT