Here's a collection of launch day video showing the Mars Science Laboratory and Atlas 5 rocket heading to orbit. All subscriptions to the Spaceflight Now+Plus video-on-demand service helps keep this website alive.

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VIDEO: THE FULL LAUNCH EXPERIENCE PLAY | HI-DEF
VIDEO: ATLAS 5 ROCKET LAUNCHES MARS SCIENCE LAB PLAY | HI-DEF
VIDEO: ONBOARD CAMERA VIEW OF NOSE CONE JETTISON PLAY | HI-DEF
VIDEO: ONBOARD CAMERA VIEW OF THE STAGING EVENT PLAY | HI-DEF
VIDEO: ONBOARD VIEW OF ROCKET RELEASING MSL PLAY
VIDEO: LAUNCH DECLARED A SUCCESS PLAY

VIDEO: LAUNCH REPLAY: OUR VIEW OF LIFTOFF PLAY | HI-DEF
VIDEO: LAUNCH REPLAYS: VAB ROOF PLAY | HI-DEF
VIDEO: LAUNCH REPLAYS: PATRICK AFB PLAY | HI-DEF
VIDEO: LAUNCH REPLAYS: SOUTH OF THE PAD PLAY | HI-DEF
VIDEO: LAUNCH REPLAYS: THE BEACH TRACKER PLAY | HI-DEF
VIDEO: LAUNCH REPLAYS: SHUTTLE PAD CAMERA PLAY | HI-DEF
VIDEO: LAUNCH REPLAYS: SHUTTLE WATER TOWER PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: TRACKER WEST OF THE PAD PLAY | HI-DEF
VIDEO: LAUNCH REPLAY: CLOSE-UP ON UMBILICALS PLAY | HI-DEF
VIDEO: LAUNCH REPLAYS: COMPLEX 41 VIF PLAY | HI-DEF
VIDEO: LAUNCH REPLAYS: THE PRESS SITE PLAY | HI-DEF

VIDEO: PRE-LAUNCH INTERVIEW WITH PROJECT MANAGER PLAY | HI-DEF
VIDEO: NARRATED PREVIEW OF ATLAS 5 ASCENT PROFILE PLAY | HI-DEF
VIDEO: ROCKET'S LAUNCH CAMPAIGN HIGHLIGHTS PLAY | HI-DEF
VIDEO: MSL'S LAUNCH CAMPAIGN HIGHLIGHTS PLAY | HI-DEF
VIDEO: SPACECRAFT CLEANROOM TOUR PLAY | HI-DEF
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Our launch photo gallery from pad cameras.

A towering Atlas 5 rocket flashed to life and vaulted into space Saturday, putting on a spectacular weekend sky show as it boosted NASA's $2.5 billion Mars Science Laboratory rover on an eight-and-a-half-month 352-million-mile voyage to the red planet.

Read our full story.

"The launch vehicle has given us a great injection into our trajectory, and we're on our way to Mars," said MSL Project Manager Peter Theisinger of NASA's Jet Propulsion Laboratory in Pasadena, Calif. "The spacecraft is in communication, thermally stable and power positive."

"We are very excited about sending the world's most advanced scientific laboratory to Mars," NASA Administrator Charles Bolden said in a post-launch statement.

"MSL will tell us critical things we need to know about Mars, and while it advances science, we'll be working on the capabilities for a human mission to the red planet and to other destinations where we've never been."

Our gallery of launch photos from the press site.

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The next Atlas launch is scheduled for February 16 from Cape Canaveral to deploy the U.S. Navy's first Mobile User Objective System (MUOS) communications satellite.

"ULA is extremely proud to have launched the Curiosity rover on its 9-month journey to the red planet," said Jim Sponnick, vice president for mission operations. "The technological innovations on this extremely sophisticated MSL mission are most impressive and we are all looking forward to the operations and scientific learning on Mars starting next August."

Contact with Mars Science Lab has been confirmed with NASA's Deep Space Tracking network's Canberra station in Australia.

"The count went really smoothly, we got off on the first opportunity at 10:02 in the morning, right on the money," NASA launch director Omar Baez says. "The flight looked great. Our parameters look great. And we separated on-time."

Within minutes of separating from the rocket, Mars Science Lab will establish communications with the Deep Space Network's tracking station in Canberra, Australia.

T+plus 44 minutes, 12 seconds. SPACECRAFT SEPARATION! The Centaur upper stage has deployed NASA's Mars Science Laboratory spacecraft on its voyage to deliver the Curiosity rover onto the surface of the red planet next August.

T+plus 43 minutes, 10 seconds. Spin up to 15 rpm has begun.

T+plus 42 minutes. Bus and battery voltages, tank pressures and other system measurements look good.

T+plus 41 minutes. Centaur is turning itself to the proper orientation for releasing the payload.

T+plus 40 minutes, 30 seconds. MECO 2. Main engine cutoff confirmed. Centaur has completed its second burn of the day, this one to give the final boost to propel the Curiosity rover out of Earth orbit.

T+plus 38 minutes, 45 seconds. Engine performance remains normal.

T+plus 38 minutes, 10 seconds. About two minutes are left in the burn to reach MSL's planned escape velocity.

T+plus 37 minutes, 55 seconds. Vehicle's current acceleration is 0.95 g's.

T+plus 37 minutes. The vehicle skirting just south of Madagascar now.

T+plus 36 minutes, 10 seconds. Continued good engine operation is being delivered by the RL10.

T+plus 35 minutes. This burn is occurring 100 nautical miles above Africa.

T+plus 34 minutes. The engine is burning well. This is a planned eight-minute firing by the Centaur's single Pratt & Whitney Rocketdyne RL10 engine.

T+plus 32 minutes, 40 seconds. Ignition! The Centaur's single RL10 engine has re-ignited to propel Mars Science Lab into its hyperbolic departure orbit.

T+plus 32 minutes, 35 seconds. Liquid hydrogen and liquid oxygen system prestarts are underway.

T+plus 31 minutes. Centaur uses its settling thrusters in preparation for the burn and also de-spinning from the roll.

T+plus 29 minutes. The rocket is approaching the coast of Africa.

T+plus 26 minutes. Now 5 minutes away from Centaur's engine restart.

T+plus 25 minutes. All vehicle parameters still reported normal.

T+plus 23 minutes. Centaur is about to perform a 2.5-second flush of liquid oxygen through the transfer lines to condition the RL10 engine for restart.

T+plus 22 minutes. Centaur's onboard systems are stable in this coast period continues.

T+plus 21 minutes. Centaur is half-way through this coast period. It is in a slow roll to keep thermal heating even across the rocket's surfaces.

T+plus 19 minutes, 15 seconds. The Mars Science Laboratory is power-positive, meaning the solar array panels on the cruise stage are collecting sunlight.

T+plus 18 minutes. Centaur data readings look normal for the coast period.

T+plus 17 minutes. The flight path is taking the vehicle over the equatorial Atlantic Ocean, soon to cross Africa. It will fly over the Indian Ocean where the RL10 will restart to accelerate Curiosity out of Earth orbit before separating the payload. Here's the planned track map.

T+plus 14 minutes. That first burn by Centaur inserted the rocket into an orbit with a high point of 166 nautical miles, a low point of 97 nautical miles and inclination of 28.9 degrees.

T+plus 11 minutes. The rocket is performing its turn to the proper position for the coast.

T+plus 10 minutes, 33 seconds. MECO 1. Centaur's main engine has shut down following its first burn today, achieving a preliminary orbit around Earth. The rocket will coast in this orbit for about 20 minutes before the RL10 engine re-ignites.

T+plus 10 minutes, 35 seconds. About one minute are left in this burn of Centaur.

T+plus 9 minutes, 50 seconds. The vehicle now 1,648 miles downrange from the Cape.

T+plus 9 minutes, 30 seconds. RL10 engine parameters still look good.

T+plus 9 minutes. All systems reported stable as the Centaur fires to reach an initial Earth orbit.

T+plus 8 minutes, 20 seconds. Now 150 miles in altitude, traveling at 15,00 mph.

T+plus 8 minutes. The RL10 continues to perform well, burning liquid hydrogen and liquid oxygen propellants.

T+plus 7 minutes, 52 seconds. The rocket has flown out of range from Florida tracking stations. Antigua Island has acquired.

T+plus 7 minutes, 5 seconds. The rocket is performing a planned 75-degree roll to improve the link with NASA's orbiting Tracking and Data Relay Satellite System.

T+plus 6 minutes, 30 seconds. The rocket is tracking right down the planned flight path.

T+plus 5 minutes, 25 seconds. The rocket is 102 miles in altitude, some 570 miles downrange and traveling 13,700 mph.

T+plus 5 minutes. Centaur engine readings look good as this burn gets underway.

T+plus 4 minutes, 42 seconds. Centaur has ignited! The RL10 engine is up and running at full thrust for its first of two planned firings today.

T+plus 4 minutes, 34 seconds. The Atlas 5's Common Core Booster first stage has been jettisoned, and the Centaur upper stage's liquid hydrogen and liquid oxygen systems are being readied for engine start.

T+plus 4 minutes, 27 seconds. BECO. Booster Engine Cutoff is confirmed as the RD-180 powerplant on the first stage completes its burn. Standing by to fire the retro thrusters and separate the spent stage.

T+plus 3 minutes, 35 seconds. The two-halves of the Atlas 5 rocket nose cone encapsulating the MSL spacecraft have separated, exposed the satellite to space. Also jettisoned was the Forward Load Reactor, a two-piece deck that rings the Centaur stage to support the bulbous fairing during launch.

T+plus 3 minutes, 15 seconds. The RD-180 main engine continues to fire normally, burning a mixture of highly refined kerosene and liquid oxygen.

T+plus 2 minutes, 50 seconds. Reaction control system has been activated.

T+plus 2 minutes, 30 seconds. Everything still looking good.

T+plus 1 minute, 57 seconds. All four of the Aerojet-made solid rocket motors have successfully separated from the Atlas 5, having completed their job of adding a powerful kick at liftoff.

T+plus 93 seconds. Solid rocket booster burnout has occurred. But the spent motors will remain attached to the first stage for a few seconds, until the Atlas 5 reaches a point where the airborne dynamic pressure reduces to an allowable level for a safe jettison.

T+plus 60 seconds. The launcher is departing Cape Canaveral to propel the Curiosity rover on its 8.5-month trajectory to reach Mars.

T+plus 50 seconds. A period of maximum dynamic pressure is being experienced by the rocket.

T+plus 45 seconds. Mach 1.

T+plus 40 seconds. The main engine is throttling down to ease the stresses on the vehicle in the lower atmosphere.

T+plus 15 seconds. Pitch, yaw and roll maneuvers are underway as the Atlas 5 aims for Mars with its RD-180 engine and four solid rocket boosters up and burning.

LIFTOFF! Liftoff of Mars Science Laboratory, using Earth's Curiosity to explore the red planet!

T-minus 20 seconds. "Go Atlas" and "Go Centaur" was just called by launch team during a final status check.

T-minus 40 seconds. Centaur's liquid oxygen and liquid hydrogen tanks are stable at flight pressures.

T-minus 1 minute. The fully fueled Atlas 5 rocket with the Mars Science Laboratory aboard currently weighs 1.17 million pounds. The vehicle will unleash nearly 2 million pounds of thrust for blastoff.

T-minus 90 seconds. The safety system has been armed.

T-minus 1 minute, 45 seconds. Liquid oxygen and liquid hydrogen propellant topping to the Centaur upper stage is being secured.

T-minus 1 minute, 55 seconds. The launch sequencer has been commanded to start.

T-minus 2 minutes. The Atlas first stage and Centaur upper stage are now switching from ground power to internal batteries.

T-minus 2 minutes, 30 seconds. The first stage RP-1 kerosene fuel tank and the liquid oxygen have stepped up to proper flight pressure levels.

T-minus 3 minutes. The Atlas first stage liquid oxygen replenishment is being secured so the tank can be pressurized for launch.

T-minus 3 minutes, 50 seconds. The ground pyrotechnics have been enabled.

T-minus 4 minutes and counting. Clocks have resumed for the final minutes of today's countdown to launch the Atlas 5 rocket with Mars Science Lab bound for the red planet. Liftoff is set to occur at 10:02 a.m. EST.

Countdown clocks will resume in one minute.

Mars Science Lab is running on internal power and configured for launch.

The ULA launch director has given his "go" for today's liftoff.

Polling of the team by Atlas launch conductor just occurred. All technical systems are reported "go" to continue with the countdown for liftoff at 10:02 a.m. EST.

Standing by for the final readiness check to be conducted. The launch team will be polled for a "go" or "no go" to proceed with the count.

The Mars Science Lab spacecraft nestled inside the nose cone of the Atlas 5 rocket is switching to internal power for launch.

Here's a look at some stats about today's mission. This will be:

• The 610th launch for Atlas program since 1957
• The 322nd Atlas to occur from Cape Canaveral
• The 28th launch of an Atlas 5 since 2002
• The 24th Atlas 5 to occur from the Cape
• The 20th Atlas 5 under United Launch Alliance
• The 1st Atlas 5 to fly in the 541 configuration
• The 6th NASA launch on Atlas 5
• The 5th Atlas launch of 2011

NASA launch director Omar Baez has polled his advisory team and given the agency's approval to proceed with the countdown.

T-minus 4 minutes and holding. The countdown has entered the planned 10-minute hold to give the launch team a chance to review all systems before pressing ahead with liftoff.

The first stage liquid oxygen tank and Centaur's liquid oxygen and liquid hydrogen tanks are reported at flight level.

T-minus 5 minutes. Standing by to go into the final built-in hold.

The official forecast for today's 103-minute launch window extending from 10:02 to 11:45 a.m. EST continues to predict good weather with just some scattered low clouds at 5,000 feet, easterly winds of 20 to 25 knots and a temperature of 73 degrees. There's no weather constraints at this time and the odds of acceptable weather during the window are 70 percent.

The only concern later would be a low-cloud ceiling below 6,000 feet that would restrict visual tracking of the rocket during its initial climb off the pad.

Now just 20 minutes away from launch.

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Mars Science Laboratory is headed for a landing on the night of August 5 between 10 and 10:30 p.m. Pacific Time (1 and 1:30 a.m. EDT Aug. 6; 0500-0530 GMT) inside the giant Gale Crater on the red planet. The target site is located at 4.5 degrees south latitude and 137.4 degrees east.

The rover is 9 feet, 10 inches long; 9 feet, 1 inch wide and 7 feet tall at top of its camera mast. The instrument-laden robotic arm, when fully extended, is 7 feet long. Its six wheels are 20 inches in diameter.

The vehicle is 1,982 pounds in mass. That includes 165 pounds for the 10 science instruments packed aboard the rover.

The fuel-fill sequence for the first stage main engine is starting.

Thirty minutes from liftoff. The countdown clocks are heading to the T-minus 4 minute mark where a planned 10-minute hold will occur. Launch of Atlas 5 remains scheduled for 10:02 a.m. EST.

Pre-launch checks of the rocket's safety system have been completed.

A direct link to our text updates.

Today's launch of the Atlas 5 rocket will be the first flight of the vehicle's 541 configuration, which is distinguished by the combination of a five-meter payload fairing, four solid rocket boosters and a single-engine Centaur upper stage.

Depending on a payload's weight and desired orbit, mission planners add strap-on solid boosters to the United Launch Alliance-made rocket to incrementally increase the vehicle's performance.

Atlas 5 vehicles are capable of flying with as many as five boosters, an option that was employed to generate as much thrust as possible to launch NASA's New Horizons space probe bound for Pluto in 2006 and NASA's Juno to Jupiter in August.

The Russian RD-180 first stage main engine will ignite at T-minus 2.7 seconds, shooting a giant cloud of steam from the pad's main exhaust duct while undergoing a check to ensure its vital signs are healthy. The four strap-on solid rocket boosters are lit at T+plus 0.8 seconds, leading to liftoff at T+plus 1.1 seconds.

The combined power will send the 20-story Atlas vehicle thundering into the sky in a hurry. Its fast speed off the launch pad will be remarkably different than other Atlas 5 missions without solid boosters that appear majestically slow.

The Aerojet-made solid boosters will burn for about 90 seconds to assist the RD-180 in propelling the rocket. The SRB casings remain attached to the first stage for a few additional seconds before separating 30 miles up.

Once out of the discernible atmosphere at an altitude of 74 miles, the bulbous nose cone encapsulating the Mars Science Lab payload can be shed at T+plus 3 minutes, 25 seconds. The fairing was made by Ruag Space of Switzerland.

The kerosene-fueled first stage will continue to fire until T+plus 4 minutes, 22 seconds. The bronze stage separates about six seconds later, leaving the hydrogen-fueled Centaur upper stage to ignite at an altitude of 105 miles for a burn lasting nearly seven minutes that will inject itself into a preliminary orbit of 102 by 201 miles high.

Centaur completes its first burn over the central Atlantic Ocean and enters a 20-minute coast. The Pratt & Whitney Rocketdyne RL10 cryogenic engine then restarts for an eight-minute firing to propel the spacecraft out of Earth orbit to begin the 354-million mile trek to reach the surface of Mars.

Mars Science Lab separates from the rocket at T+plus 42 minutes, 48 seconds over the Indian Ocean while traveling at 22,866 mph. The craft will establish communications with the Canberra tracking station in Australia a short time later to phone home with Mission Control.

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Fast-filling of the first stage liquid oxygen tank has been completed. Topping mode is now underway.

The first stage liquid oxygen tank is 90 percent full now.

The liquid hydrogen tank in the Centaur upper stage just reached the 97 percent level. Topping is now beginning.

The latest briefing to mission managers shows the weather odds remain 70 percent chance acceptable for the Atlas 5 rocket to fly. Air Force meteorologists are calling for some scattered clouds at 3,500 and 5,000 feet, possibly some isolated rain showers, good visibility, easterly winds of 18 to 24 knots and a temperature of 73 degrees F.

Now 60 minutes from liftoff. Fueling of the Atlas rocket with cryogenic liquid oxygen and liquid hydrogen is proceeding as planned for a liftoff at 10:02 a.m. EST.

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Passing the half-full mark on Centaur's liquid hydrogen tank.

Centaur's liquid hydrogen tank is 30 percent full. The cryogenic propellant will be consumed with liquid oxygen by the stage's Pratt & Whitney Rocketdyne-made RL10 engine.

First stage liquid oxygen tank is 50 percent full thus far. Chilled to Minus-298 degrees F, the liquid oxygen will be used with RP-1 kerosene by the RD-180 main engine on the first stage during the initial four-and-a-quarter minutes of flight today. The 25,055 gallons of RP-1 were loaded into the rocket earlier.

Chilldown of the liquid hydrogen system has been accomplished. The launch team has received the "go" to begin filling the Centaur upper stage with the supercold fuel.

The Centaur engine chilldown sequence is being initiated.

The first stage liquid oxygen tank has reached the 20 percent mark.

Upper stage liquid oxygen has reached flight level.

Now just 90 minutes away from launch.

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The first stage liquid oxygen loading is switching from slow-fill to fast-fill mode.

The Centaur liquid oxygen tank reached the 95 percent level. The topping off process is starting now.

The cumulus cloud rule violation has been lifted. Weather is "go" at the time.

The chilldown conditioning of liquid hydrogen propellant lines at Complex 41 is starting to prepare the plumbing for transferring the Minus-423 degree F fuel into the rocket. The Centaur holds about 12,319 gallons of the cryogenic propellant.

Centaur liquid oxygen is three-quarters loaded.

The conditioning of the systems for the first stage liquid oxygen tank have been completed. And a "go" has been given to begin pumping supercold liquid oxygen into the Atlas 5's first stage.

The Common Core Booster stage's liquid oxygen tank is the largest tank to be filled today. It holds 48,744 gallons of cryogenic oxidizer for the RD-180 main engine.

The Centaur upper stage's liquid oxygen tank is 50 percent full.

Now approaching the one-third level of the Centaur's liquid oxygen tank.

The Centaur liquid oxygen tank has reached the 10 percent mark already.

Filling of the Centaur upper stage with about 4,076 gallons of liquid oxygen has begun at Cape Canaveral's Complex 41 following the thermal conditioning of the transfer pipes.

The liquid oxygen -- chilled to Minus-298 degrees F -- will be consumed during the launch by the Centaur's single RL10 engine along with liquid hydrogen to be pumped into the stage a little later in the countdown. The Centaur will perform two firings to propel the payload -- initially into a parking orbit and then out of Earth orbit today.

Local weather conditions have gone "red" temporarily due to some cumulus clouds moving overhead the Cape.

The Centaur liquid oxygen pad storage area has been prepped. The next step is conditioning the transfer lines, which is now beginning to prepare the plumbing for flowing the cryogenic oxidizer.

T-minus 120 minutes and counting! The launch countdown is continuing on schedule for today's flight of the Atlas 5 rocket with the Mars Science Laboratory.

Clocks have one more built-in hold planned at T-minus 4 minutes. That pause will last 10 minutes during which time the final "go" for launch will be given. All remains targeted for liftoff at 10:02 a.m. EST from Cape Canaveral's Complex 41.

In the next couple of minutes, chilldown thermal conditioning of the mobile launch platform upon which the rocket stands will begin. This is meant to ease the shock on equipment when supercold cryogenic propellants start flowing into the rocket.

All console operators have reported a "ready" status during the pre-fueling readiness poll.

The ULA launch director Lou Mangieri also voiced his approval for moving forward with the countdown as scheduled today.

Loading of cryogenic liquid oxygen and liquid hydrogen into the Atlas 5 rocket will be getting underway a short time from now.

Launch conductor Scott Barney at the Atlas Spaceflight Operations Center is briefing his team on procedures before entering into the final two hours of the countdown.

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The Complex 41 pad and the danger area has been cleared of all workers for the remainder of the countdown.

T-minus 2 hours and holding. The countdown has just entered the first of two planned holds over the course of the day that will lead to the 10:02 a.m. EST launch of the Atlas rocket. This initial pause lasts 30 minutes, giving the team some margin in the countdown timeline to deal with technical issues or any work that is running behind. The final hold is scheduled to occur at T-minus 4 minutes and will last for 10 minutes.

The latest weather update to launch managers shows things are unchanged. There's still a 70 percent chance of acceptable conditions during today's launch window. Air Force meteorologists today have introduced a scattered-to-variable-broken deck of clouds at 5,000 feet, along with the previously forecast scattered deck at 3,500 feet. If the clouds become widespread enough to be called "broken" below 6,000 feet, that would constitute a ceiling and be "no go" for launch.

Good day from the Kennedy Space Center where it's a cloudy bit cloudy but the countdown is progressing toward a rocket launch to the red planet. We're now watching the final three hours in the countdown for today's flight of the Atlas 5 rocket and the Mars Science Laboratory spacecraft. Liftoff remains scheduled for 10:02 a.m. EST from Cape Canaveral's Complex 41.

Earlier this morning, the launch team encountered a ground electrical component problem that technicians have worked to replace. It should have no real impact to today's countdown.

Hydraulic and propulsion system preps on the Atlas first stage have been finished.

The guidance system testing has been reported complete.

Also, testing is being conducted of the C-band system used to track the rocket as it flies downrange, the S-band system for telemetry relay from vehicle and the vehicle's internal batteries.

The hazard area roadblocks around the launch site's safety perimeter are being established now. And the launch team has started configuring the pad's water deluge system.

The weather outlook for today's 103-minute launch window continues to predict a 70 percent chance of being acceptable for the Atlas 5 rocket to fly. Air Force meteorologists are calling for some scattered clouds at 3,500 and 5,000 feet, possibly some isolated rain showers, good visibility, easterly winds of 18 to 24 knots and a temperature of 73 degrees F.

If the launch should slip to tomorrow for some reason, similar weather is expected as meteorologists once again give a 70 percent chance of acceptable conditions. The odds are 40 percent favorable on Monday as a cold front sweeps into the area.

It's launch day for dispatching the most advanced roving vehicle to the surface of another world -- the Mars Science Laboratory spacecraft aboard the Atlas 5 vehicle. The countdown clocks are starting to tick, beginning a seven-hour sequence of work that will prepare the rocket, payload and ground systems for today's blastoff.

Soon the launch team will begin powering up the rocket to commence standard pre-flight tests. Over the subsequent few hours, final preps for the Centaur's liquid oxygen and liquid hydrogen systems will be performed, along with a test of the rocket's guidance system and the first stage propulsion and hydraulic preps, internal battery checks and testing of the C-band system used to track the rocket as it flies downrange, plus a test of the S-band telemetry relay system. The Complex 41 site will be cleared of all personnel at 7:07 a.m.

A planned half-hour hold begins at 7:22 a.m. when the count reaches T-minus 120 minutes. Near the end of the hold, the team will be polled at 7:49 a.m. to verify all is in readiness to start fueling the rocket for launch.

Supercold liquid oxygen begins flowing into the Centaur upper stage around 8:09 a.m., followed by the first stage filling around 8:22 a.m. Liquid hydrogen fuel loading for Centaur will be completed a short time later.

A final hold is scheduled at the T-minus 4 minute mark starting at 9:48 a.m. That 10-minute pause will give everyone a chance to finish any late work and assess the status of the rocket, payload, Range and weather before proceeding into the last moments of the countdown.

Today's launch window extends from 10:02 to 11:45 a.m. EST (1502-1645 GMT).

Here's our comprehensive collection of pre-flight video showing the Mars Science Laboratory and Atlas 5 rocket getting ready to fly. All subscriptions to the Spaceflight Now+Plus video-on-demand service helps keep this website alive.

Additional coverage for subscribers:
VIDEO: ATLAS ROCKET ROLLS OUT TO LAUNCH PAD PLAY | HI-DEF
VIDEO: TIME-LAPSE VIEWS OF ROCKET ROLLOUT PLAY | HI-DEF

VIDEO: THE PRE-LAUNCH NEWS CONFERENCE PLAY
VIDEO: CURIOSITY ROVER SCIENCE BRIEFING PLAY
VIDEO: LOOKING FOR LIFE IN THE UNIVERSE PLAY
VIDEO: WHAT WE KNOW ABOUT THE RED PLANET PLAY
VIDEO: ROBOTICS AND HUMANS TO MARS TOGETHER PLAY

VIDEO: PREVIEW OF ENTRY, DESCENT AND LANDING PLAY | HI-DEF
VIDEO: PREVIEW OF CURIOSITY ROVER EXPLORING MARS PLAY | HI-DEF
VIDEO: A FLYOVER OF THE GALE CRATER LANDING SITE PLAY | HI-DEF

VIDEO: NUCLEAR GENERATOR HOISTED TO ROVER PLAY | HI-DEF
VIDEO: MARS SCIENCE LAB MOUNTED ATOP ATLAS 5 PLAY | HI-DEF
VIDEO: MOVING MSL TO ATLAS ROCKET HANGAR PLAY | HI-DEF
VIDEO: SPACECRAFT PLACED ABOARD TRANSPORTER PLAY | HI-DEF

VIDEO: APPLYING MISSION LOGOS ON THE FAIRING PLAY | HI-DEF
VIDEO: MSL ENCAPSULATED IN ROCKET'S NOSE CONE PLAY | HI-DEF
VIDEO: FINAL LOOK AT SPACECRAFT BEFORE SHROUDING PLAY | HI-DEF

VIDEO: HEAT SHIELD INSTALLED ONTO SPACECRAFT PLAY | HI-DEF
VIDEO: BEAUTY SHOTS OF SPACECRAFT PACKED UP PLAY | HI-DEF
VIDEO: ATTACHING THE RING-LIKE CRUISE STAGE PLAY | HI-DEF
VIDEO: PARACHUTE-EQUIPPED BACKSHELL INSTALLED PLAY | HI-DEF
VIDEO: SKYCRANE AND CURIOSITY MATED TOGETHER PLAY | HI-DEF

VIDEO: TWO-HALVES OF ROCKET NOSE CONE ARRIVES PLAY | HI-DEF
VIDEO: CENTAUR UPPER STAGE HOISTED ATOP ATLAS PLAY | HI-DEF
VIDEO: FINAL SOLID ROCKET BOOSTER ATTACHED PLAY | HI-DEF
VIDEO: FIRST OF FOUR SOLID BOOSTERS MOUNTED PLAY | HI-DEF
VIDEO: FIRST STAGE ERECTED ON MOBILE LAUNCHER PLAY | HI-DEF
VIDEO: STAGES DRIVEN FROM HARBOR TO THE ASOC PLAY | HI-DEF
VIDEO: ROCKET ARRIVES ABOARD SEA-GOING VESSEL PLAY | HI-DEF

VIDEO: STOWING ROVER'S INSTRUMENTED ROBOT ARM PLAY | HI-DEF
VIDEO: DEPLOYING CURIOSITY'S SIX WHEELS ON EARTH PLAY | HI-DEF
VIDEO: MMRTG PUT BACK INTO STORAGE AT SPACEPORT PLAY | HI-DEF
VIDEO: NUCLEAR GENERATOR FIT-CHECK ON THE ROVER PLAY | HI-DEF
VIDEO: ROVER'S NUCLEAR POWER SOURCE ARRIVES PLAY | HI-DEF
VIDEO: SPIN-TESTING THE RING-LIKE CRUISE STAGE PLAY | HI-DEF

VIDEO: UNCOVERING CURIOSITY ROVER IN CLEANROOM PLAY | HI-DEF
VIDEO: UNVEILING THE ROCKET-POWERED SKYCRANE PLAY | HI-DEF
VIDEO: UNBOXING THE ROVER FROM SHIPPING CRATE PLAY | HI-DEF
VIDEO: ROVER HAULED FROM RUNWAY TO PHSF FACILITY PLAY | HI-DEF
VIDEO: MARS ROVER ARRIVES AT KENNEDY SPACE CENTER PLAY | HI-DEF

VIDEO: DESCENT WEIGHTS INSTALLED ON BACKSHELL PLAY | HI-DEF
VIDEO: SOLAR ARRAY PANELS ATTACHED TO CRUISE RING PLAY | HI-DEF
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NASA's photography of today's Atlas 5 rocket rollout to the launch pad with Curiosity rover is posted in this gallery.

We're posted more photos showing the Atlas 5 rocket poised on the launch pad.

The weather forecast continues to call for a 70 percent chance of favorable conditions during Saturday morning's launch window. The possibility of cumulus cloud constraints or a low-cloud ceiling below 6,000 feet are the only concerns.

The outlook at launch time includes scattered clouds at 3,500 and 30,000 feet, isolated showers in the area, good visibility, easterly winds of 18 to 22 knots and a temperature around 72 degrees F.

"High pressure over the peninsula with fair weather conditions and a stationary front south of the peninsula. Pressure gradient remains tight with on-shore breezy winds," Air Force meteorologists report.

"On launch day, East winds gusting in the upper teens to low 20s are expected with a small coastal shower threat with the on-shore winds. Sufficient low level moisture remains over Central Florida to monitor for a potential cloud ceiling violation with on-shore flow. The primary concerns for launch is a low cloud ceiling and cumulus clouds."

The odds are 70 and 40 percent favorable, respectively, on the backup launch opportunities available Sunday and Monday.

"In the event of a 24-hour delay, the next cold front is expected to advance into the Florida panhandle area by launch time with south-southeasterly to southerly winds gusting in the upper teens. The primary concerns for a 24-hour delay is a low cloud ceiling and cumulus clouds.

"In the event of a 48-hour delay, the aforementioned cold front is expected to push into Central Florida Sunday night/Monday morning with cloudy conditions, isolated rainshowers, and a threat of thunderstorms. Strengthening southwesterly winds are expected in advance of the front with gusty winds in the mid to upper 20s behind the front Monday afternoon. The primary concerns for launch are cumulus clouds, thick clouds, a ceiling, and ground winds."

Check out today's gallery of photos showing the Atlas 5 rocket being rolled to the launch pad.

On the pad! The Atlas 5 rocket has arrived at the Complex 41 pad for tomorrow's ascent with the Mars-bound Curiosity rover, completing the first third-of-a-mile on the spacecraft's 354-million-mile trek to our neighboring planet.

"The Mars Science Lab and rover Curiosity is locked and loaded, ready for final countdown on Saturday's launch to Mars," says Colleen Hartman, assistant associate administrator of NASA's Science Mission Directorate.

The two mobile trailers connected to the launching platform, which were part of the convoy during this morning's rollout, soon will be hooked up to power and communications systems at the pad. These trailers provide conditioned air to the payload and communications with the rocket during the rollout and the countdown. They are protected from the blast of launch by a concrete structure on the north-side of the platform.

Within the next hour, the auto couplers between the pad and platform will be engaged to route umbilical connections from the ground to the rocket for tomorrow's fueling of the booster with cryogenic propellants.

Later today, the undercarriages used to move the mobile platform will be disconnected and the "trackmobiles" pulled free.

Ground crews will secure the rocket for a quiet evening leading into tomorrow's launch opportunity. Countdown clocks will start ticking seven hours before liftoff time.

The day's 103-minute launch window opens at 10:02 a.m. and closes at 11:45 a.m. EST.

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Now getting centered up on the pad.

The rocket is passing through the pad entrance gate.

Some rollout pictures from the press viewing location are posted on our Facebook page.

The Atlas 5 rocket is emerging from its vehicle assembly building for the journey to the launch pad.

Riding atop a mobile launching platform, the 197-foot-tall space booster is moving to Cape Canaveral's Complex 41 for this much-anticipated flight to send NASA's Curiosity rover on its trek to Mars.

"This mission represents the culmination of years of hard work by NASA and the ULA launch teams. We began to integrate the mission onto Atlas in 2006, and we look forward to Curiosity's landing on the surface of Mars and to learning whether the Mars' environment is capable of supporting microbial life," said Vernon Thorp, program manager for NASA Missions at United Launch Alliance.

The rocket's rollout to the pad has begun!

This slow half-hour drive from the 30-story Vertical Integration Facility to Cape Canaveral's Complex 41 pad uses a pair of specially-made "trackmobiles" to carry the rocket's 1.4-million pound mobile launching platform along rail tracks for the 1,800-foot trip.

The two-stage rocket was put together inside the assembly building in September and the Mars Science Lab spacecraft was mounted atop the vehicle earlier this month.

The Atlas 5 is designed to spend minimal time at the launch pad, which does not include a service gantry like other sites.

Good morning from atop a camera mound about a mile southeast of Complex 41 where photographers and reporters have gathered to cover this morning's rollout of the Atlas 5 rocket to the launch pad from the assembly building.

The trip is expected to begin at 8 a.m. EST. You can watch the roll in our live streaming video.

NASA's $2.5 billion Mars Science Laboratory rover, the most complex and scientifically powerful robotic spacecraft ever built to explore the surface of another world, is poised for launch Saturday on a high-stakes mission to look for organic compounds and signs of past or present habitability.

Read our preview story.

The Launch Readiness Review has concluded and given the "go" to continue with Saturday's liftoff plans. Officials convened this morning's meeting to examine the status of the Atlas rocket, the MSL spacecraft, the network of ground support and the weather forecast. The review culminated with formal consensus to press ahead with countdown operations starting with Friday morning's rocket rollout to the Complex 41 pad.

Join us on this page for live streaming video of the pre-launch news conference starting at 1 p.m. EST (1800 GMT) today on this page.

The new battery was installed into the Atlas 5 rocket's safety system and successfully tested today, officials report, clearing the way for launch preparations to continue toward a Saturday morning blastoff.

The Launch Readiness Review will be held Wednesday morning, followed by the pre-launch news conference at 1 p.m. EST. We'll have live streaming video coverage of that briefing from the Kennedy Space Center.

The LRR is the formal meeting the gives the final approve to proceed with rolling the rocket to the launch pad, which is targeted for Friday morning at 8 a.m. EST.

The weather forecast calls for a 70 percent chance of favorable conditions during Saturday's 103-minute-long launch window. The possibility of cumulus cloud or low ceiling constraints are the only concerns.

The outlook at launch time includes scattered low and high clouds, isolated showers in the area, good visibility, easterly winds of 20 to 24 knots and a temperature around 70 degrees F.

"Today, high pressure off the mid-Atlantic states with on-shore winds over the Florida peninsula introduces a threat of a coastal shower. On Wednesday, a cold front transits the peninsula through the day with frontal passage expected Wednesday evening and through the overnight hours. In advance of the front, there is a threat of isolated showers and a small threat of an isolated thunderstorm," Air Force meteorologists report.

"The cold front pushes south through Thanksgiving day and expected to stall south of the peninsula on Friday. Winds behind the front quickly transition to on-shore Thursday afternoon and become breezy.

"For MLP roll Friday morning, breezy east-northeast winds are expected with gusts in the mid to upper 20s. With the breezy on-shore winds, there is a coastal shower threat through the morning hours with a slightly reduced threat in the afternoon. No lightning is expected.

"On launch day, east to east-southeast winds gusting in the mid 20s are expected with a continued coastal shower threat with the on-shore winds. Sufficient low level moisture remains behind the front to monitor for a potential cloud ceiling violation with on-shore flow. The primary concerns for launch are cumulus clouds and a low ceiling."

The odds of acceptable weather on the backup launch dates of Sunday and Monday are 70 and 40 percent favorable, respectively.

"In the event of a 24-hour delay, the next cold front is expected to advance into the Florida panhandle area by launch time with Southerly winds gusting in the upper teens/low 20s. The primary concerns for a 24 hour delay are cumulus clouds and a low cloud ceiling," forecasters say.

"In the event of a 48-hour delay, the aforementioned cold front is expected to push into Central Florida Monday morning with cloudy conditions, isolated rainshowers, and a threat of thunderstorms. Strong southerly winds are expected Sunday afternoon in advance of the front and persisting through frontal passage. The primary concerns for launch are cumulus clouds, thick clouds, a ceiling, and ground winds."

A replacement battery is being activated in preparation for tomorrow's installation into the Atlas 5 rocket's safety system. The original battery showed low voltage during pre-flight testing, a NASA spokesman says, prompting the swap out and one-day delay to the launch date.

The battery is part of the rocket's self-destruct system that would terminate the flight if a major problem occurs during ascent.

Otherwise, preparations remain on target for a Saturday morning blastoff at 10:02 a.m. EST (1502 GMT).

Earlier this morning, NASA hosted a press tour of the Radiological Control Center at Kennedy Space Center where local, state and federal officials will be stationed during launch. They will model the atmospheric conditions prior to liftoff to determine where the plume from a launch accident would travel and monitor deployed measurement devices that would detect if any plutonium is released from the Curiosity's power generator. A picture is posted on our Facebook page.

DELAY. Launch of the Mars Science Laboratory on the Atlas 5 rocket has been postponed a day to give time for replacement of a suspect safety system battery aboard the booster.

Liftoff is rescheduled for next Saturday at 10:02 a.m. EST (1502 GMT).

See the launch windows chart for further details on liftoff opportunities through Dec. 18.

With its nuclear battery installed, the Mars-bound Curiosity rover was powered up Friday at exactly 2:35:10 p.m. EST (1935:10 GMT). The MMRTG device contains 10.6 pounds of plutonium-238 to convert heat energy to electricity for powering the rover throughout its mission.

"The flight vehicle is in great shape - all power and thermal readings are within expected ranges," says David Gruel, Mars Science Lab's assembly, test and launch operations manager.

Workers are removing the ground support equipment that was used to install the power source onto the rover and completing the final closeout activities to button up the vehicle for launch.

The long-range weather outlook for next Friday's launch window calls for some gusty winds at Cape Canaveral. But meteorologists don't expect the winds will violate the 33-knot limit at launch time, a NASA spokesperson says.

The Flight Readiness Review was conducted this morning and culminated with NASA officials granting approval to continue with preparations for launching the Mars Science Lab next Friday morning as scheduled.

The nuclear power source was plugged into the Curiosity rover yesterday, and now final closeouts to button up the spacecraft and rocket nose cone are underway.

The Launch Readiness Review will occur Tuesday morning to assess the status of work, any outstanding issues and give the clearance for the Atlas rollout to the pad.

Rollout is planned for Wednesday morning at 10 a.m. EST (1500 GMT).

The teams will take the Thanksgiving holiday off, the come back in early Friday to start the 7-hour countdown sequence leading to blastoff at 10:25 a.m. EST (1525 GMT).

Engineers installed the plutonium power source on NASA's Curiosity rover Thursday, adding the final piece to the complex robot before its Nov. 25 blastoff to Mars.

The Multi-Mission Radioisotope Thermoelectric Generator, or MMRTG, moved from a preparation building to the Atlas 5 rocket's Vertical Integration Facility early Thursday.

The 99-pound device was lifted inside the building and inserted through an access door on the rocket's bulbous white payload fairing. Technicians placed the power source on Curiosity through an opening on the spacecraft's backshell, which encloses the rover and its landing system during the journey from Earth to Mars.

Read our full story.

With three weeks left until blastoff, the Mars Science Laboratory has been placed atop the United Launch Alliance Atlas 5 rocket that will send the spacecraft on its journey to the Red Planet.

Already packed within the Swiss-made nose cone, the rover was raised off the ground by overhead cranes and gently maneuvered through the open doorway of the rocket's vertical assembly hangar this morning. It was positioned over the Centaur upper stage and successfully attached. Work to affix the nose cone's ogive section was continuing late into the evening.

The fully stacked rocket now stands 20 stories tall. The vehicle features a main stage fed with refined kerosene and liquid oxygen, four strap-on solid propellant boosters, the liquid hydrogen-powered cryogenic Centaur upper stage and a composite payload shroud 16 feet in diameter.

We've posted a few photo galleries of recent events, including MSL being encapsulated in the nose cone, then getting placed aboard the transporter and today's mounting atop the Atlas 5.

Shrouded inside a white bullet-shaped rocket nose cone, NASA's next Mars rover was slowly towed to the launch pad Thursday and hoisted atop its Atlas booster for liftoff to the Red Planet on Nov. 25.

Read our full story.

The rover has entered into the hangar above the Centaur upper stage for attachment.

Hoisting of Mars Science Lab is underway.

Mars Science Lab reached the rocket's Vertical Integration Facility at 4:35 a.m. EDT. The overhead crane is being attached to the payload in preparation for lifting the rover atop the Atlas 5 today.

The motorized transporter is departing from Kennedy Space Center's Payload Hazardous Servicing Facility for the middle-of-the-night trip hauling the Mars Science Lab to the Atlas 5 rocket's assembly building.

Gusty winds in Central Florida delayed the Mars Science Laboratory's trip to meet its rocket today, but the forecast calls for better conditions Thursday that should permit the $2.5 billion mission to move one step closer to the Red Planet.

Already encapsulated inside a five-meter payload fairing, MSL is scheduled to be slowly trucked from its processing building at the Kennedy Space Center industrial area to the seaside Complex 41 in the predawn hours Thursday.

Once the probe arrives at the Vertical Integration Facility, a crane will hoist the craft atop the Atlas 5 rocket.

Liftoff of the Mars mission is scheduled for Nov. 25 at 10:25 a.m. EST (1525 GMT). The rover will make a parachuted rocket-powered descent to the Martian surface in August 2012.

The United Launch Alliance Atlas 5 rocket that will propel the Mars Science Laboratory on its voyage to the Red Planet underwent a full countdown rehearsal today.

The rocket, minus the payload, was rolled to the Complex 41 pad at Cape Canaveral on Wednesday for the traditional pre-launch test.

The giant booster consisting of its bronze-colored first stage, Centaur upper stage and four strap-on solid-fuel rockets was recently assembled together atop the mobile launching platform at the Vertical Integration Facility.

The Wet Dress Rehearsal activities that each Atlas undergoes prior to launch saw the rocket fully fueled today for a realistic practice countdown.

Clocks ticked toward a simulated liftoff time at 2:10 p.m. EDT before the countdown ended and the rocket safed.

The event is designed to iron out any problems with the hardware and exercise the launch team.

The supercold fuels were offloaded this afternoon and the vehicle allowed to warm up before it is returned to the assembly building tomorrow.

Once back inside the VIF, final pre-flight work will get underway. Attachment of the MSL payload is scheduled for early November.

Liftoff remains targeted for November 25 at 10:21 a.m. EST (1521 GMT).

United Launch Alliance has begun assembling the Atlas 5 rocket that will dispatch NASA's Curiosity rover to Mars in November.

See a photo gallery of the first stage going up.

Engineers finished up functional testing of the $2.5 billion Mars Science Laboratory last week, verifying the Curiosity rover can make it to Mars and pursue scientific clues that the planet may have once harbored life.

NASA will start configuring the car-sized rover for launch this week, then cocoon the sensitive robot inside a protective heat shield and ready the craft for liftoff.

The Curiosity rover's destination is Gale crater, a scenic impact site carved out of the Martian landscape when a comet or asteroid stuck the planet long ago. The crater spans 96 miles across, and Curiosity is aiming for a narrow target at the base of a lofty mountain towering nearly three miles high.

Read our full story.