BY JUSTIN RAY

Additional coverage for subscribers:
VIDEO: THE FULL LAUNCH EXPERIENCE PLAY
VIDEO: DELTA 2 ROCKET LIFTS OFF WITH KEPLER PLAY | HI-DEF
VIDEO: KEPLER SUCCESSFULLY SEPARATES FROM ROCKET PLAY
VIDEO: UPDATE FROM THE NASA LAUNCH MANAGER PLAY

VIDEO: LAUNCH REPLAY: KSC TRACKER PLAY
VIDEO: LAUNCH REPLAY: UCS 23 TRACKER PLAY
VIDEO: LAUNCH REPLAY: TOWER CAMERA PLAY
VIDEO: LAUNCH REPLAY: PATRICK AFB PLAY
VIDEO: LAUNCH REPLAY: PAD CAMERA PLAY
VIDEO: LAUNCH REPLAY: PRESS SITE 1 PLAY
VIDEO: LAUNCH REPLAY: TRIDENT BLUFF LOCATION PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: SECOND VIEW FROM BLUFF PLAY | HI-DEF

VIDEO: AN INTERVIEW WITH NASA'S SCIENCE CHIEF PLAY
VIDEO: LAUNCH PAD'S SERVICE TOWER ROLLED BACK PLAY | HI-DEF
VIDEO: HIGHLIGHTS OF KEPLER LAUNCH CAMPAIGN PLAY | HI-DEF
VIDEO: HIGHLIGHTS OF THE DELTA 2'S LAUNCH CAMPAIGN PLAY

VIDEO: THURSDAY'S PRE-LAUNCH NEWS CONFERENCE PLAY
VIDEO: SCIENTISTS PREVIEW THE KEPLER MISSION PLAY
VIDEO: KEPLER PRE-FLIGHT OVERVIEW BRIEFING PLAY
VIDEO: SPACECRAFT MOUNTED ATOP ROCKET AT PAD 17B PLAY | HI-DEF
VIDEO: LEAVING ASTROTECH FOR TRIP TO LAUNCH PAD PLAY | HI-DEF
VIDEO: CANISTER PUT AROUND KEPLER FOR PAD MOVE PLAY | HI-DEF
VIDEO: SOLID-FUEL THIRD STAGE ATTACHED TO KEPLER PLAY | HI-DEF
VIDEO: BEAUTY SHOTS OF OBSERVATORY IN CLEANROOM PLAY | HI-DEF
VIDEO: SPACECRAFT UNPACKED AT ASTROTECH FACILITY PLAY | HI-DEF
VIDEO: KEPLER ARRIVES ON FLORIDA'S SPACE COAST PLAY | HI-DEF
VIDEO: DELTA ROCKET'S SECOND STAGE ERECTED PLAY | HI-DEF
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SATURDAY, MARCH 7, 2009
0600 GMT (1:00 a.m. EST)

"It was a stunning launch," said Jim Fanson, the Kepler project manager. "Our team is thrilled to be a part of something so meaningful to the human race -- Kepler will help us understand if our Earth is unique or if others like it are out there."

0540 GMT (12:40 a.m. EST)

Lighting up the night sky, a Delta 2 rocket roared to life and vaulted away from the Cape Canaveral Air Force Station late Friday, boosting a powerful space telescope into orbit around the sun for a $591 million mission to search for Earth-like planets orbiting distant stars.

Read our full story.

0530 GMT (12:30 a.m. EST)

"We congratulate NASA and our mission partners on the launch of Kepler on its journey to learn more about our universe," said Jim Sponnick, United Launch Alliance's vice president, Delta Product Line.

"Today's launch was the second for NASA aboard a Delta 2 in just 28 days, coming on the heels of the successful NOAA-N Prime launch Feb. 6. The NASA/ULA Delta 2 partnership has launched many important scientific missions directly benefiting everyone here on Earth. Launching these two missions for NASA has been a wonderful way to celebrate the program's 20th anniversary."

This is the 86th consecutive successful Delta 2 rocket launch dating back to May 1997. The Delta 2's overall history since debuting in 1989 has achieved 139 successes in 141 flights.

"Our Delta 2 team is proud of our success record and the contributions Delta 2 has made to scientific exploration, national defense, and economic prosperity," Sponnick said. "The team realizes that they didn't do this alone. Delta 2 has been so successful because of tremendous support from our government mission partners, suppliers and commercial customers."

The next Delta 2 rocket launch is just a couple of weeks away. The rocket is stacked on neighboring pad 17A for a mission to deploy the newest Global Positioning System satellite on March 24. The day's launch window will extend from 4:34 to 4:49 a.m. EDT.

0527 GMT (12:27 a.m. EST)

The Deep Space Network's Goldstone tracking site in California has established communications with the Kepler spacecraft as it flies away from Earth. The official time for acquisition of signal was clocked at 12:11:56 a.m. EST, NASA says, and a quick look of telemetry indicates all is well.

0518 GMT (12:18 a.m. EST)

NASA spokespeople say they're awaiting an initial state of health check for the Kepler observatory as telemetry is received via the tracking station network.

0505 GMT (12:05 a.m. EST)

A few moments ago, NASA launch manager Omar Baez said:

"So far, the countdown and the launch appeared nominal. We did see some delays in getting the data retransmitted back from halfway across the world to back here in Hangar AE. We're still trying to troubleshoot why we had that delay, but it appears we've hit the mark events that we had planned up to and including spacecraft separation. Our next event would be the spacecraft acquisition at Goldstone at 15 minutes and that should pretty much give us a good indication of how the spacecraft is doing. Unfortunately, we didn't have all the data available for us at the right time. It's coming in late, and I'm actually seeing the folks looking at that data as I speak here and reviewing it. Unfortunately, I can't give you information on how the orbit went. I'm assuming it went nominally. I don't see people pulling their hair out or anything, but they're looking at the data."

0454 GMT (11:54 p.m. EST Fri.)

SPACECRAFT SEPARATION! The Kepler spacecraft is on its way to search for Earth-like planets in the galaxy. Release from the Delta 2 rocket's third stage is confirmed, finishing tonight's launch sequence.

0453 GMT (11:53 p.m. EST Fri.)

Telemetry engineers are awaiting confirmation of spacecraft separation from the third stage.

0449 GMT (11:49 p.m. EST Fri.)

T+plus 59 minutes, 10 seconds. Events of the third stage spin up, separation from the second stage and ignition occurred within 2-3 seconds of the expected timeline, the telemetry manager reports.

0447 GMT (11:47 p.m. EST Fri.)

T+plus 57 minutes, 30 seconds. The third stage completes the Delta 2 rocket's powered flight for the launch of Kepler. Separation of the payload is about five minutes away.

0445 GMT (11:45 p.m. EST Fri.)

T+plus 55 minutes, 58 seconds. Third stage is firing! The Thiokol Star 48B motor will boost the Kepler satellite out of Earth orbit.

0445 GMT (11:45 p.m. EST Fri.)

T+plus 55 minutes, 30 seconds. The solid-fueled third stage has spun up and separated.

0444 GMT (11:44 p.m. EST Fri.)

T+plus 54 minutes, 24 seconds. SECO 2. The orbit adjustment burn was completed as the rocket flies near the western coast of Australia.

In the next minute, tiny thrusters on the side of the rocket will be fired to spin up the vehicle in preparation for jettison of the second stage.

0443 GMT (11:43 p.m. EST Fri.)

T+plus 53 minutes, 17 seconds. The second stage engine has ignited for the 64-second firing to propel its 2,300-pound spacecraft payload into a higher orbit.

0434:57 GMT (11:34:57 p.m. EST Fri.)

T+plus 45 minutes. Tracking stations in Australia will be acquiring the rocket's signal to receive telemetry during the upcoming mission milestones. The Dongara station should see the second stage's minute-long firing and separation from the third stage. Coverage will be provided by the Tennant Creek facility during the third stage firing and release of Kepler.

0429:57 GMT (11:29:57 p.m. EST Fri.)

T+plus 40 minutes. As this coast phase of the launch continues, you can see a map of the rocket's planned track here.

0419:57 GMT (11:19:57 p.m. EST Fri.)

T+plus 30 minutes. The rocket is coasting until the second stage restarts its engine at T+plus 53 minutes for a brief 64-second firing to put the vehicle into an elliptical orbit with a high point over 1,100 miles high. That will be followed by the third stage's operation and deployment of Kepler some 62 minutes after liftoff.

0414:57 GMT (11:14:57 p.m. EST Fri.)

T+plus 25 minutes. The official liftoff time was 10:49:57.465 p.m. EST.

0409:57 GMT (11:09:57 p.m. EST Fri.)

T+plus 20 minutes. As the rocket coasts in this parking orbit, it performs a "BBQ roll" maneuver to keep the thermal conditions on the vehicle equal. This maneuver was scheduled to start at about T+plus 17 minutes, 50 seconds and conclude at T+plus 44 minutes, 57 seconds.

0402 GMT (11:02 p.m. EST Fri.)

T+plus 12 minutes, 35 seconds. As the rocket passes out of range from the Antigua tracking station. A data blackout is created until the Delta's signal is acquired via a ground station in Australia about 40 minutes from now.

0400 GMT (11:00 p.m. EST Fri.)

T+plus 10 minutes, 5 seconds. SECO 1 has been confirmed. The second stage's Aerojet-made engine completed its initial burn for the launch. Delta and Kepler have reached orbit.

0359 GMT (10:59 p.m. EST Fri.)

T+plus 9 minutes, 10 seconds. The rocket is 103 miles in altitude, 1,240 miles downrange from the launch pad and traveling at 15,994 mph.

0358 GMT (10:58 p.m. EST Fri.)

T+plus 8 minutes, 5 seconds. About two minutes remain in this burn of the second stage engine to achieve the intended parking orbit.

0357 GMT (10:57 p.m. EST Fri.)

T+plus 7 minutes, 50 seconds. Delta is 99.9 miles in altitude, 955 miles downrange from the launch pad and traveling at 14,899 mph.

0356 GMT (10:56 p.m. EST Fri.)

T+plus 6 minutes, 55 seconds. Delta is 95 miles in altitude, 778 miles downrange from the launch pad and traveling at 14,271 mph.

0356 GMT (10:56 p.m. EST Fri.)

T+plus 6 minutes, 15 seconds. Delta is 89 miles in altitude, 641 miles downrange from the launch pad and traveling at 13,834 mph.

0356 GMT (10:56 p.m. EST Fri.)

T+plus 5 minutes, 55 seconds. The second stage is firing normally as the Delta arcs out over the Atlantic.

0355 GMT (10:55 p.m. EST Fri.)

T+plus 5 minutes, 5 seconds. The rocket's 10-foot-diameter nose cone enclosing the Kepler spacecraft has been jettisoned.

0354 GMT (10:54 p.m. EST Fri.)

T+plus 4 minutes, 58 seconds. The Delta's second stage engine ignition confirmed.

0354 GMT (10:54 p.m. EST Fri.)

T+plus 4 minutes, 41 seconds. MECO. The first stage main engine cutoff has occurred. Standing by for separation of the spent stage.

0354 GMT (10:54 p.m. EST Fri.)

T+plus 4 minutes, 15 seconds. The vehicle is 62 miles in altitude.

0353 GMT (10:53 p.m. EST Fri.)

T+plus 3 minutes, 30 seconds. The first stage main engine still firing well. The Pratt & Whitney Rocketdyne powerplant consumes kerosene fuel and liquid oxygen to produce about 200,000 pounds of thrust.

0353 GMT (10:53 p.m. EST Fri.)

T+plus 3 minutes, 5 seconds. The Delta 2 rocket is 43 miles in altitude and traveling over 6,980 mph.

0352 GMT (10:52 p.m. EST Fri.)

T+plus 2 minutes, 27 seconds. The Delta 2 rocket is 31.3 miles in altitude and traveling over 5,300 mph.

0352 GMT (10:52 p.m. EST Fri.)

T+plus 2 minutes, 15 seconds. The three air-ignited solid rocket boosters have burned out and separated. The rocket is now flying solely on the power generated by the liquid-fueled first stage main engine.

0351 GMT (10:51 p.m. EST Fri.)

T+plus 1 minutes, 40 seconds. The vehicle is 15 nautical miles in altitude, 35.6 miles downrange from the launch pad, traveling at 3,393 mph.

0351 GMT (10:51 p.m. EST Fri.)

T+plus 1 minute, 20 seconds. All six ground-start solid rocket boosters have burned out of propellant and separated from the Delta 2's first stage. A moment before the jettison occurred, the three remaining motors strapped to rocket ignited to continue assisting the rocket's RS-27A main engine on the push to space.

0350 GMT (10:50 p.m. EST Fri.)

T+plus 50 seconds. The rocket has flown through the area of maximum aerodynamic pressure in the lower atmosphere. The vehicle is riding the power of its first stage main engine and six of the strap-on boosters.

0350 GMT (10:50 p.m. EST Fri.)

T+plus 35 seconds. Delta has broken the sound barrier.

0350 GMT (10:50 p.m. EST Fri.)

T+plus 15 seconds. The Delta 2 rocket thundering away from Cape Canaveral for its Friday night flight to space.

0349:57 GMT (10:49:57 p.m. EST Fri.)

LIFTOFF! Liftoff of the Kepler spacecraft, a planet-finder seeking out habitable new worlds in the galaxy.

0349:27 GMT (10:49:27 p.m. EST Fri.)

T-minus 30 seconds. SRB ignitors will be armed at T-minus 11 seconds.

The launch ignition sequence will begin at T-minus 2 seconds when a launch team member triggers the engine start switch. The process begins with ignition of the two vernier thrusters and first stage main engine start. The six ground-lit solid rocket motors then light at T-0 for liftoff.

0348:57 GMT (10:48:57 p.m. EST Fri.)

T-minus 1 minute. All remains "go" for launch.

0348 GMT (10:48 p.m. EST Fri.)

T-minus 1 minute, 45 seconds. The launch pad water suppression system is being activated.

0347:57 GMT (10:47:57 p.m. EST Fri.)

T-minus 2 minutes. The first stage liquid oxygen vents are now being closed so the LOX tank can be pressurized for launch. Puffs of vapor from a relief valve on the rocket will be seen in the remainder of the countdown as the tank pressure stabilizes.

0347 GMT (10:47 p.m. EST Fri.)

T-minus 2 minutes, 30 seconds. The Kepler spacecraft have been declared "go" for launch.

About 1.3 million labor hours have been spent working on the Ball Aerospace-built spacecraft over the last five years to prepare the sophisticated planet-hunting machine for its mission to find new worlds.

0346:57 GMT (10:46:57 p.m. EST Fri.)

T-minus 3 minutes and counting. The rocket's third stage safe and arm devices are being armed.

0346 GMT (10:46 p.m. EST Fri.)

T-minus 3 minutes, 45 seconds. The Delta 2 rocket's systems are now transferring to internal power for launch. And the launch pad water system is being enabled.

0345:57 GMT (10:45:57 p.m. EST Fri.)

T-minus 4 minutes and counting! Clocks are ticking down the final moments to liftoff of the Delta 2 rocket with the Kepler spacecraft. Launch is set for 10:49:57 p.m. EST from Cape Canaveral Air Force Station in Florida.

Following liftoff, the vehicle will head eastward on a 62-minute flight to deploy the observatory.

0345 GMT (10:45 p.m. EST Fri.)

Now five minutes from launch! The "go" has been given to resume the countdown for launch.

0344 GMT (10:44 p.m. EST Fri.)

Kepler is undergoing final configuring for launch.

0342 GMT (10:42 p.m. EST Fri.)

A readiness poll of the launch team has resulted in a "go" to restart the countdown as scheduled for an on-time liftoff tonight.

0339:57 GMT (10:39:57 p.m. EST Fri.)

Kepler is just 10 minutes away from leaving Earth on its mission to find planets orbiting other stars in our galactic neighborhood.

"Kepler will push back the boundaries of the unknown in our patch of the Milky Way Galaxy, and it's discoveries may fundamentally alter humanity's view of itself," said Jon Morse, director of the Astrophysics Division at NASA Headquarters.

The mission is named for the German scientist who pioneered the fields of optics and planetary motion. "Now 400 years later, we're using his discoveries in order to answer a profound and fundamental question about our place in the Universe: are there other Earth-like planets out there?"

0339 GMT (10:39 p.m. EST Fri.)

NASA launch manager Omar Baez just completed his final pre-launch poll. No constraints were voiced by the space agency managers overseeing tonight's mission.

0336 GMT (10:36 p.m. EST Fri.)

United Launch Alliance mission director Rich Murphy just conducted a readiness poll of his team.

0335:57 GMT (10:35:57 p.m. EST Fri.)

T-minus 4 minutes and holding. The countdown has entered the final planned built-in hold. This is a scheduled 10-minute pause leading to tonight's liftoff time of 10:49:57 p.m. EST for the Delta 2 rocket with Kepler.

0334 GMT (10:34 p.m. EST Fri.)

The launch weather officer confirms the current conditions are acceptable for liftoff of the Delta 2 rocket this evening.

0331 GMT (10:31 p.m. EST Fri.)

The first stage fuel tank is being pressurized for launch.

0324:57 GMT (10:24:57 p.m. EST Fri.)

T-minus 15 minutes and counting. Countdown clocks are running again following the planned 20-minute hold. The count will continue to the T-minus 4 minute mark where another planned hold is scheduled. Launch remains set to occur at 10:49:57 p.m. EST.

0324 GMT (10:24 p.m. EST Fri.)

The launch director has given the OK to resume the count.

0322 GMT (10:22 p.m. EST Fri.)

The launch team members were just polled for a "ready" status to continue with the countdown.

0314:57 GMT (10:14:57 p.m. EST Fri.)

Kepler will become the 215th primary payload put into space by the venerable Delta 2 rocket over the past 20 years. Here's a look at some other stats about tonight's mission. This will be:

• The 339th Delta rocket launch since 1960
• The third Delta of 2009
• The 141st Delta 2 rocket mission since 1989
• The 44th Delta 2 mission for NASA
• The 67th Delta 2 rocket fly in the 7925 configuration
• The 106th Delta 2 rocket to fly from Cape Canaveral
• The 46th Delta 2 launch from pad 17B

0304:57 GMT (10:04:57 p.m. EST Fri.)

T-minus 15 minutes and holding. Clocks have entered the first of two planned hold periods during the final portion of the Terminal Countdown. This pause will last 20 minutes in duration.

These holds are designed to give the launch team a chance to deal with any problems and catch up on work that could be running behind schedule.

0300 GMT (10:00 p.m. EST Fri.)

The first stage engine steering checks just finished. Technicians will take the next few minutes to review the data from the tests to confirm all went per the plan.

0257 GMT (9:57 p.m. EST Fri.)

The second stage engine slews are complete. First stage tests have begun.

0255 GMT (9:55 p.m. EST Fri.)

The launch team is beginning the "slew" or steering checks of the first and second stage engines. These are gimbal tests of the nozzles on the first stage main engine and twin vernier engines and second stage engine to ensure the rocket will be able to steer itself during launch.

0249:57 GMT (9:49:57 p.m. EST Fri.)

Everything continues to look good with 60 minutes left in the countdown for the launch of Kepler aboard a Delta 2 rocket from Cape Canaveral.

Kepler will stare at the same part of the sky for more than three years, carefully measuring the brightness of 100,000 stars. The observatory will catch the moments when planets pass in front of their stars and detect the worlds blinking out the starlight. The data will tell scientists the size and orbit of the discovered planet.

"Trying to detect Jupiter-size planets crossing in front of their stars is like trying to measure the effect of a mosquito flying by a car's headlight. Finding Earth-sized planets is like trying to detect a very tiny flea in that same headlight," said Jim Fanson, the Kepler project manager.

Debra Fischer, professor of astronomy at San Francisco State University explains what is expected during the Kepler mission:

"What I'm hoping, expecting to see as a community scientist is in the first six months to a year, the big, massive hot Jupiters are going to roll off the Kepler assembly line. This is exciting because these are bizarre planets. We don't really understand the statistics, how they form, how they moved into their current position and just the sheer number of these objects that Kepler will find is going to help us learn a lot about the systems."

"And then the next class of planets I think will roll out will be perhaps the hot Neptunes...Significantly smaller than Jupiter, these objects are thought to exist around something like 30 percent of stars like our sun and low-mass stars. And if that is correct, then Kepler should see quite a few of these very large, something like 17 times the mass of the Earth, orbiting."

"And then the hardest detection and by far the most exciting is going to be the detection of bona fide Earths -- small, rocky planets, Earth-size planets."

Jon Morse, director of the Astrophysics Division at NASA Headquarters, adds:

"This is why I call Kepler our planetary census taker. We're going to get the full sweep of the types of planets in different types of orbits around different types of stars through a big cross-section of our galaxy....It is going to shape the way that we formulate our plans for future missions on our quest to find Earth-like planets and study their atmospheres and look for the bio-markers like the types of molecules in our atmosphere that may indicate life."

0247 GMT (9:47 p.m. EST Fri.)

The checks of the rocket's safety systems are underway. That will be followed a short time from now by engine steering tests.

0240 GMT (9:40 p.m. EST Fri.)

If you are heading out to the beach to watch tonight's launch and want to receive occasional countdown updates, sign up for our Twitter feed to get text message updates on your cellphone. U.S. readers can also sign up from their phone by texting "follow spaceflightnow" to 40404. (Standard text messaging charges apply.)

0239:57 GMT (9:39:57 p.m. EST Fri.)

T-minus 40 minutes and counting. Countdown clocks are continuing to the T-minus 15 minute mark where a 20-minute built-in hold is planned. A final 10-minute hold at T-minus 4 minutes will lead to the target liftoff time of 10:49:57 p.m. EST.

0234 GMT (9:34 p.m. EST Fri.)

Loading of the Delta 2 rocket's first stage liquid oxygen tank has been accomplished. Tonight's 27-minute, 18-second process concluded at 9:33:39 p.m.

The rocket is now fully fueled for launch. The vehicle's first stage was successfully loaded with RP-1 kerosene fuel an hour ago. The second stage was filled with its storable nitrogen tetroxide and Aerozine 50 fuels on Tuesday. The third stage and nine strap-on booster rockets are solid-propellant.

0226 GMT (9:26 p.m. EST Fri.)

Liquid oxygen loading has been underway for 20 minutes. Once the first stage tank is 95 percent full, the "rapid load" valve will be closed and the slower "fine load" phase will continue to fill the rocket.

0219:57 GMT (9:19:57 p.m. EST Fri.)

The Kepler spacecraft is ready for its Friday night flight into space. Liftoff is just 90 minutes away.

"We've had a great day today. The spacecraft been powered on since early this morning. And all systems are 'go' at this point," says John Troeltzsch, the Ball Aerospace program manager.

0218 GMT (9:18 p.m. EST Fri.)

Now 12 minutes into this approximate 25-minute process to fill the first stage liquid oxygen tank. A bright white plume of vapors have begun streaming from a vent on the rocket and the bottom of the vehicle is icing over as the super-cold liquid oxygen continues to flow into the first stage.

0206 GMT (9:06 p.m. EST Fri.)

LOX loading begins! Cryogenic liquid oxygen, chilled to Minus-298 degrees F, has started flowing from the storage reservoir at Complex 17, through plumbing and into the bottom of the Delta 2 rocket. The LOX will be consumed by the first stage main engine during the first four-and-a-half minutes of flight along with the 10,000 gallons of RP-1 kerosene already loaded aboard the vehicle.

0200 GMT (9:00 p.m. EST Fri.)

The launch team has a "go" to begin preparations for loading the rocket's first stage liquid oxygen tank as planned.

0153 GMT (8:53 p.m. EST Fri.)

NASA launch manager Omar Baez just polled the agency team for a "go" to begin loading the rocket's first stage liquid oxygen tank. No constraints were voiced.

"NASA team is ready for cryo tanking," Baez reported.

0149:57 GMT (8:49:57 p.m. EST Fri.)

With two hours remaining until launch, there's no problems being reported on the Delta 2 rocket or Kepler spacecraft. Weather conditions are excellent with only some scattered clouds and light southeasterly winds.

0148 GMT (8:48 p.m. EST Fri.)

Work to turn on and configure the Delta's onboard guidance computer has been completed.

0147 GMT (8:47 p.m. EST Fri.)

Launch weather officer Joel Tumbiolo just gave an update to mission managers. "We have a real good weather night for you," the veteran meteorologist for Delta launches reported.

There's no concerns about violating rules governing clouds, rain or winds. So that means the forecast calls for a 100 percent chance of acceptable conditions.

0140 GMT (8:40 p.m. EST Fri.)

The next major task in the countdown will be loading super-cold cryogenic liquid oxygen into the first stage starting in approximately 25 minutes.

The kerosene and liquid oxygen will be consumed by the stage's Pratt & Whitney Rocketdyne RS-27A main engine and twin vernier steering thrusters during the initial four-and-a-half minutes of flight.

0135 GMT (8:35 p.m. EST Fri.)

The first stage fuel tank of the Delta 2 rocket has been fully loaded for tonight's planned 10:49 p.m. EST launch. The tank was filled with a highly refined kerosene, called RP-1, during a 19-minute, 42-second process that concluded at 8:34:59 p.m.

0131 GMT (8:31 p.m. EST Fri.)

Rapid-loading of the RP-1 tank has concluded as 9,800 gallons have been pumped into the rocket. Fine load is continuing.

0128 GMT (8:28 p.m. EST Fri.)

The launch team has computed that the full load for the first stage fuel tank is 10,042 gallons.

Once the tank is filled to 98 percent or 9,800 gallons, the "rapid load" valve will be closed and the slower "fine load" phase will continue to top off the tank.

0127 GMT (8:27 p.m. EST Fri.)

Just over the 7,000-gallon mark now.

0120 GMT (8:20 p.m. EST Fri.)

First stage propellant loading has passed the 3,000-gallon mark. This process to load the kerosene fuel takes about 20 minutes.

0115 GMT (8:15 p.m. EST Fri.)

Fueling begins! About 10,000 gallons of the kerosene propellant, called RP-1, are pumping into the base of the rocket from storage tanks at pad 17B as fueling of the Delta 2's first stage begins for tonight's launch.

0111 GMT (8:11 p.m. EST Fri.)

Preparations for loading the Delta 2 rocket's first stage RP-1 fuel tank are beginning. After verifying valves, sensors, flow meters and equipment are ready, the highly refined kerosene fuel will start flowing into the vehicle a few minutes from now.

0110 GMT (8:10 p.m. EST Fri.)

The first stage helium and nitrogen systems have been pressurized. And the "go" has been given for the start of fueling operations.

0100 GMT (8:00 p.m. EST Fri.)

Two launch windows are available tonight. The Delta 2 rocket can lift off during either of the periods:

• Window 1: 10:49:57 to 10:52:57 p.m. EST
• Window 2: 11:17:44 to 11:20:44 p.m. EST

And another 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 message updates on your cellphone. U.S. readers can also sign up from their phone by texting "follow spaceflightnow" to 40404. (Standard text messaging charges apply.)

0054 GMT (7:54 p.m. EST Fri.)

The rocket's control system and guidance computer are being turned on.

And the launch team is starting the steps to pressurize the first and second stage helium and nitrogen systems and the second stage fuel and oxidizer tanks.

0049:57 GMT (7:49:57 p.m. EST Fri.)

Terminal Countdown begins! The three-hour countdown sequence has started for the Delta rocket. Between now and the precise 10:49:57 p.m. launch time, the rocket's guidance system will be activated, onboard tanks pressurized, the kerosene fuel and liquid oxygen supplies loaded into the first stage, checks performed on the safety system, steering tests conducted on the engines, then the final switches to internal power and arming of the ignitors.

0041 GMT (7:41 p.m. EST Fri.)

The launch team has been polled to ensure all stations are manned and systems are set for the Terminal Countdown. Each team member voiced a "ready" to begin the count.

FRIDAY, MARCH 6, 2009
2349 GMT (6:49 p.m. EST)

T-minus 150 minutes and holding. The countdown just entered the first of three planned holds that will occur over the course of the night. This first pause is 60 minutes long.

The two later holds -- at the T-minus 15 minute and the T-minus 4 minute points -- will give the launch team some time to deal with issues and catch up on any work running behind. Those two holds combined add up to a half-hour in duration.

2315 GMT (6:15 p.m. EST)

A collection of photos from today's rollback of the mobile service tower can be seen here.

2249 GMT (5:49 p.m. EST)

The countdown is entering the final five hours until the Delta 2 rocket thunders away from Cape Canaveral carrying NASA's Kepler space observatory.

Kepler is looking for the Goldilocks of planets, a search to find Earth-like worlds in the habitable zone around stars. The data from the space telescope will allow scientists to determine if a discovered planet orbits so close to the parent star that it would be too hot for life, a long way from the star causing the world to be frozen or in the sweet spot where water would be liquid and life could form.

"We are interested in finding planets that are not too hot, not too cold, but just right. We are looking for planets with a temperature that's just about right for liquid water on the surface of the planet. That's the area we think might be conducive to life," said principal investigator Bill Borucki.

"We will monitor a wide range of stars; from small cool ones, where planets must circle closely to stay warm, to stars bigger and hotter than the sun, where planets must stay well clear to avoid being roasted. Everything about the mission is optimized to find Earth-size planets with the potential for life, to help us answer the question -- are Earths bountiful or is our planet unique?"

He added that the Kepler mission "is one of many steps we are taking to explore the galaxy for life."

2100 GMT (4:00 p.m. EST)

The Kepler mission aims to find planets like Earth where life could evolve. Most of the distant worlds found to date are giant gas planets like Jupiter and Saturn, and now scientists are eager to see what else is out there in the galaxy.

"The exoplanet exploration, which is the discovery and study of planets outside our own solar system, is a relatively new and quickly blossoming field in astrophysics. The first planet outside our solar system was confirmed only in 1995 and now there are over 300 exoplanets known. Most of these planets do not have Earth-like sizes or orbits," said Jon Morse, director of the Astrophysics Division at NASA Headquarters.

"I think the one thing that we've learned from exoplanet science over the last decade and a half is that what exists is an incredibly random, chaotic, wild range of planets. We started out thinking small, just looking at our own solar system, and our eyes have been definitely opened by the wide range of discovery and diversity," said Debra Fischer, professor of astronomy at San Francisco State University.

"We're finding planets that float like a piece of foam on water -- very, very low density. We're finding some planets with densities heavier than that of lead. It's just astounding the range of planets we are finding. And not just the planets, but the orbits. Everybody expected the orbits were going to be nearly circular when we first started this game, but what we have found is the orbits are often highly elliptical," said Bill Borucki, Kepler's principal investigator.

"Often we think of these Earth-like planets as truly rocky worlds with solid surfaces. In fact, I think that the science fiction writers are going to be challenged to imagine the diversity that we could expect to find, even in this type of planets. They may not be rocky worlds, they may be water worlds without plate tectonics that force the landmass up above the oceans. These could be worlds that, in fact, have life like our oceans, OK? But perhaps not sending radio signals to us."

Kepler's data will determine the frequency of Earth-like planets around other stars and pave the way for future missions.

"The Kepler mission is a critical component, therefore, in NASA's broader efforts in exoplanet research and astrobiology. Not only will its discoveries be profound on their own merits, but they will also significantly impact our future planning of missions," Morse said.

1942 GMT (2:42 p.m. EST)

Achieving a key pre-flight milestone for tonight's launch, the pad's service gantry has rolled back from the United Launch Alliance Delta 2 rocket to allow final preparations to proceed as planned.

The mobile service tower was used to stack the three-stage vehicle, the nine strap-on solid rocket motors and the Kepler payload atop the pad's launch mount. The tower also provided the primary weather protection and worker access to the rocket during its stay at the oceanside complex since on-pad assembly began in October.

Ground teams will spend the next couple of hours getting the pad secured in advance of the three-hour-long Terminal Countdown. Launch remains targeted for 10:49 p.m. EST (0349 GMT).

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1933 GMT (2:33 p.m. EST)

The tower is in motion again, bound for its launch position a safe distance away from the rocket.

1914 GMT (2:14 p.m. EST)

Rollback of the launch pad tower has started at Cape Canaveral Air Force Station's Complex 17 for tonight's flight of the Delta 2 rocket with Kepler.

The mobile gantry is moved a small distance and stopped while workers apply tension the lanyards on the umbilicals running to the Delta 2 vehicle. Once that is completed, the tower will be driven away to fully reveal the 12-story rocket.

1900 GMT (2:00 p.m. EST)

Retraction of the pad gantry has not yet occurred. But it appears the ground team should get the tower moving shortly.

1730 GMT (12:30 p.m. EST)

Crews at launch pad 17B finished work on the Kepler spacecraft this morning and sealed the access door on the Delta 2 rocket's nose cone. Retraction of platforms in the mobile service tower and final inspections of the vehicle are underway in preparation for retracting the gantry early this afternoon.

Right now, photographers from news media organizations are setting up their sound-activated cameras around the pad to capture tonight's launch.

Liftoff remains scheduled for 10:49 p.m. EST.

1545 GMT (10:45 a.m. EST)

It is launch day for Kepler, NASA's first mission capable of detecting Earth-size planets around stars similar to our sun. A Delta 2 booster stands ready for liftoff from Cape Canaveral at 10:49 p.m. EST tonight on an hour-long flight that will accelerate the spacecraft to a speed exceeding six miles per second and soaring beyond our home planet's orbit.

The 12-story rocket is propelled off the launch pad with its main engine and six strap-on solid-propellant boosters firing to generate over 700,000 pounds of thrust.

A minute into the ascent, the rocket will already be 10 nautical miles up as those six solid motors extinguish and separate. Three remaining solids are ignited for their minute-long firing.

The slender blue first stage keeps its RS-27A engine roaring through the initial four-and-a-half-minutes, climbing about 70 nautical miles over the Atlantic Ocean before being jettisoned. That allows the hypergolic second stage engine to ignite and push the vehicle into a preliminary orbit 100 nautical miles high.

The second stage will settle into the parking orbit about 10 minutes after liftoff and begin a quiet coast to the other side of the planet where the launch sequence resumes about 40 minutes later near the western coast of Australia.

Another firing of the second stage, this time lasting just 64 seconds, begins the process of pushing Kepler farther away from Earth. The end result of this burn will be an orbit 1,180 miles at apogee and 94 miles at perigee.

Tiny thrusters then ignite to rapidly "spin up" the third stage and attached satellite to 55 rpm. The second stage separates from the spinning duo some 55 minutes after liftoff.

The solid-fuel third stage is lit moments later, delivering a minute-and-a-half of thrust to propel the 2,300-pound satellite into a solar orbit trailing the Earth.

After a yo-yo system is unfurled from the rocket to stop the spinning motion, the satellite is cast free from the spent stage 62 minutes into the ascent.

Over the mission's life, Kepler will slowly drift away from Earth at a rate of 9 million miles per year in its own 371-day orbit around the sun.

THURSDAY, MARCH 5, 2009

In a galaxy of 200 billion or more stars, one could argue planets like Earth must be common. NASA plans to take a major step toward answering that question, one way or the other, with launch of a Delta 2 rocket Friday carrying Kepler, a sophisticated satellite equipped with one of the most powerful digital cameras ever flown in space.

Read our mission preview story.

1955 GMT (2:55 p.m. EST)

All systems are "go" for Friday night's blastoff of the Delta 2 rocket from Cape Canaveral carrying Kepler, a planet-finding machine that will look for Earth-size worlds around stars in the galaxy.

A pair of precise three-minute launch opportunities will be available, opening at 10:49:57 p.m. and 11:17:44 p.m. EST, respectively, said Omar Baez, the NASA launch director.

The first window would send the rocket on a flight azimuth of 93 degrees, reaching a preliminary orbit inclined 28.5 degrees to the equator about 10 minutes after liftoff.

The second window would use a flight azimuth of 99 degrees, achieving an initial orbit inclined 29.3 degrees.

Switching from one window to the other will require the launch team to perform a flight program upload to the rocket's guidance computer, Baez said.

Final preps at Complex 17 will get underway Friday morning as technicians finish buttoning up the Delta rocket. Rollback of the mobile service tower at pad 17B is expected to be completed by 2 p.m. EST.

Mission managers will be on-station by 5:30 p.m. to oversee the final hours of the pre-flight procedures. All workers should be out of the pad area by 7 p.m.

The Terminal Countdown commences at 7:49 p.m. Fueling of the first stage with kerosene propellant will begin about 20 minutes later, followed by the loading of liquid oxygen starting a little after 9 p.m.

Two holds are planned at the T-minus 15 minute and T-minus 4 minute points to build in margin for the launch team to deal with any problems that crop up. The final hold will sync up the clocks with the target liftoff time.

A final review of the launch preparations was conducted this morning and granted approval to proceed into Friday's countdown operation.

"We held our Launch Readiness Review this morning and that was very successful," Baez said. "We are ready to fly tomorrow."

The Air Force-led weather team says the forecast remains excellent for a Friday launch.

"It looks like the weather will cooperate quite nicely," said Lt. Greg Strong of the 45th Weather Squadron.

The forecast calls for just a few clouds at 3,000 feet, visibility of 10 miles, southeasterly winds from 130 degrees at 8 peaking to 12 knots and a temperature of 63-65 degrees F.

The latest outlook says there's less than a five percent chance of violating any of the launch weather rules, specifically the cumulus cloud or thick cloud constraints.

Watch this page for live updates throughout Friday's countdown and Kepler's trek to orbit aboard the Delta 2 rocket.

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1545 GMT (10:45 a.m. EST)

The Launch Readiness Review was held at Cape Canaveral this morning and concluded with managers giving the official "go" to continue with Friday night's flight of the Delta 2 rocket and Kepler spacecraft, NASA says.

The pre-launch press conference is coming up at 1 p.m. EST from the Kennedy Space Center. Check back later today for a full preview of the countdown and Kepler's mission to discover habitable new worlds.

WEDNESDAY, MARCH 4, 2009
1715 GMT (12:15 p.m. EST)

The odds of acceptable weather for Friday's launch have gotten even better. There's now a 95 percent chance that conditions will be within limits for liftoff at 10:49 p.m. EST.

The updated forecast calls for just a few clouds at 3,000 feet, visibility of 10 miles, southeasterly winds from 130 degrees at 8 peaking to 12 knots and a temperature of 63-65 degrees F.

The only slight worry -- a five percent chance -- is that the cloud cover will be greater than expected and violate either the cumulus cloud rule or the thick cloud rule.

TUESDAY, MARCH 3, 2009

Storable hypergolic propellants were loaded into the Delta 2 rocket's second stage today in preparation for Friday's launch to dispatch the Kepler planet-finder into space.

Technicians at Cape Canaveral Air Force Stations's pad 17B filled the stage a hydrazine propellant mixture and nitrogen tetroxide oxidizer. The fuels will power the stage's Aerojet-made main engine during the two firings needed to propel the spacecraft away from Earth.

The first burn will inject the rocket into an initial 100-mile-high parking orbit about 10 minutes into the flight, setting up a quiet coast over the Eastern Atlantic, Africa and the Indian Ocean. The engine restarts about 40 minutes later to boost the rocket into an elliptical orbit before the solid-fuel third stage takes over and boosts Kepler out of Earth orbit.

Pre-flight preparations will continue Wednesday with closeouts of the rocket's compartments and other testing.

The Launch Readiness Review will be held on Thursday morning for senior management to discuss the progress of pre-flight work, any technical issues and the status of the rocket, payload and ground support systems. If all goes well, the meeting concludes with officials giving the formal approval to proceed with Friday's launch.

1715 GMT (12:15 p.m. EST)

Weather conditions shouldn't be a factor during Friday's countdown and launch of the Kepler space telescope, meteorologists reported this morning.

"Surface and upper level high pressure over the southeast U.S and western Atlantic will be the dominant weather feature resulting in benign weather conditions over central Florida throughout the week including launch day," the weather team says.

At launch time Friday night, the forecast calls for just a few clouds at 3,000 feet, visibility of 10 miles, southerly winds from 160 degrees at 8 peaking to 12 knots and a temperature of 63-65 degrees F.

There's just a 10 percent chance that the cumulus clouds could violate the launch rules.

MONDAY, MARCH 2, 2009

NASA's Kepler space observatory has been cleared for blastoff Friday night following an extensive review to spot similarities in the nose cone and separation systems between its Delta 2 rocket and another launcher that failed last week.

Liftoff of the planet-seeking telescope aboard a three-stage Delta vehicle is scheduled for 10:49 p.m. EST from Cape Canaveral's pad 17B.

Senior NASA and rocket engineers gathered Monday for the Flight Readiness Review, a meeting that took on added attention because of last Tuesday's mishap with an Orbital Sciences Taurus booster. That rocket's nose cone failed to separate three minutes into flight, dooming an environmental satellite.

In the wake of the accident, NASA kicked off an examination of the Delta 2 rocket's shroud and associated ordnance to see if there was any reason for concern on the Kepler launch.

The readiness review began Monday morning, then adjourned while an engineering board met in the afternoon to finish crossing off the remaining items on the list being double-checked between Taurus and Delta. The FRR resumed Monday evening and affirmed plans to proceed with the Kepler launch preparations.

"They had a very methodical process of going through and eliminating commonalities and similarities. In the end, they really didn't find any. So we are 'go' to proceed," NASA spokesman George Diller said.

The Delta 2 has flown 140 times and achieved a success rate of nearly 99 percent.

Fueling of the Delta's second stage with storable hypergolic propellants will occur on Tuesday, as well as the mission dress rehearsal to practice running through the launch day timeline.

Managers will meet again Thursday to assess to the progress of work and give the OK to enter into Friday's countdown.

THURSDAY, FEBRUARY 26, 2009

Engineers preparing to launch NASA's Kepler spacecraft aboard a Delta 2 rocket have delayed their liftoff to make sure the problem that doomed another booster this week won't repeat.

A Taurus rocket carrying the space agency's Orbiting Carbon Observatory failed to reach orbit Tuesday morning when its nose cone didn't separate. An investigation is underway into that mishap that ruined the $273 million environmental mission, which was launched from Vandenberg Air Force Base, California.

At Cape Canaveral's pad 17B today, workers were busy installing the Delta's 10-foot-diameter nose cone fairing around the Kepler telescope for next week's planned launch.

Although the rockets are made by different companies -- the Delta is built by United Launch Alliance and the Taurus is operated by Orbital Sciences -- officials are double-checking any commonality in the fairing and separation systems.

Kepler was scheduled for liftoff on the evening of March 5. But NASA announced today that the launch would be pushed back at least a day to finish the fairing analysis.

Launch on March 6 will be possible during a pair of opportunities at 10:49 and 11:13 p.m. EST.

The Flight Readiness Review to give approval to proceed with final pre-launch activities is planned for next Monday.

SATURDAY, FEBRUARY 21, 2009

A space telescope that will search for Earth-like planets in the galaxy was mounted atop a Delta 2 rocket at its Cape Canaveral launch pad Saturday.

NASA's Kepler spacecraft is scheduled for launch March 5.

Efforts to hoist the craft into the towering gantry at pad 17B were thwarted by bad weather and high winds on Thursday and Friday mornings.

After leaving the Astrotech satellite processing complex near Titusville and driving into Cape Canaveral Air Force Station on Thursday, managers were forced to put the spacecraft inside a military building for temporary storage due to the unacceptable weather.

Kepler went to the pad Friday morning but couldn't be lifted then either, again returning to a nearby facility to wait out the winds.

But despite the weather's interference to the pre-launch schedule, NASA says the back to back delays are not expected to postpone the March 5 liftoff date. An agency spokesman said there's enough slack in the schedule to make up the lost time.

Kepler was delivered to Florida's Space Coast on January 6 from builder Ball Aerospace & Technologies' factory in Boulder, Colorado. Technicians put the spacecraft through final testing and then loaded storable propellant for the mission.

A solid-fuel Star 48B motor that serves as the Delta 2 rocket's third stage was brought into the cleanroom for attachment beneath the spacecraft. The two were joined together February 16. Two days later, the payload was enclosed in a protective transportation canister and placed aboard a trailer for the trip to launch pad 17B.

The United Launch Alliance Delta 2 rocket to propel Kepler into a solar orbit trailing Earth is known as the 7925-10L configuration. The three-stage vehicle has the added power of nine strap-on solid rocket boosters.

On-pad stacking of the rocket began October 21 with erection of the first stage. The 10-foot-diameter nose cone will be installed around Kepler next week to complete the rocket assembly process.

A pair of three-minute launch windows will be available March 5 for the Delta rocket to lift off. They open at precisely 10:48:43 p.m. and 11:16:34 p.m. EST.

Kepler will stare at stars in a patch of the Milky Way to detect the faint dimming of light indicative of passing planets. The spacecraft is equipped with a 95-megapixel array of charged couple devices, known as CCDs, the largest camera ever flown in space.

"The Kepler vehicle is really a marvel of engineering," said Jim Fanson, the Kepler project manager from the Jet Propulsion Laboratory. "In order to find these (planets), we have to be able to measure the brightness changes of the stars down to the 20 part per million level, that's an extremely challenging measurement. It's akin to measuring a flea as it creeps across the headlight of an automobile at night. That's the level of precision we have to achieve."

The observatory is designed to find rocky planets orbiting at the right distance from their parent stars where liquid water, and perhaps life, could exist.

"Kepler's mission is to determine whether Earth-size planets in the habitable zone of other stars are frequent or rare; whether life in our Milky Way galaxy is likely to be frequent or rare," said William Borucki, the Kepler science principal investigator at NASA's Ames Research Center.