BY JUSTIN RAY

Follow the countdown and launch of the ULA Atlas 5 rocket carrying the ICO G1 mobile communications spacecraft. Reload this page for the latest on the launch.

Additional coverage for subscribers:
VIDEO: ATLAS 5 LAUNCHES ICO G1 AS SEEN FROM PRESS SITE PLAY
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MONDAY, APRIL 14, 2008

Thundering out of Cape Canaveral on its first commercial flight in two years and carrying its heaviest payload ever, an Atlas 5 rocket on Monday afternoon successfully launched a mobile communications satellite to assist and entertain Americans on the go.

Read our launch story

A full gallery of launch photos is available here.

2117 GMT (5:17 p.m. EDT)

Ground controllers have acquired the first signals from the ICO G1 spacecraft. Today's highly successful launch delivered the satellite within one nautical mile of the target orbit.

Check back later tonight for a wrap-up story, photo galleries and video clips of the launch.

2042 GMT (4:42 p.m. EDT)

T+plus 30 minutes, 49 seconds. SPACECRAFT SEPARATION! The Centaur upper stage has deployed the ICO G1 mobile communications spacecraft, completing this afternoon's launch.

Weighing 14,625 pounds, the commercial satellite is the heaviest payload ever launched by an Atlas rocket. Built by Space Systems/Loral, the craft stands over 27 feet tall, features a 39-foot-diameter mesh reflector antenna that will be unfurled in space and a pair of power-generating solar wings to span over 100 feet tip-to-tip once extended in orbit.

The satellite and a network of ground repeaters will enable ICO to market an interactive media service combining live TV, enhanced navigation and emergency assistance across the United States starting next year.

2041 GMT (4:41 p.m. EDT)

T+plus 29 minutes, 50 seconds. Centaur has achieved the correct position to separate the payload.

2040 GMT (4:40 p.m. EDT)

T+plus 28 minutes, 40 seconds. The rocket is 194 miles in altitude, 6,760 miles downrange, traveling at 22,633 mph.

2040 GMT (4:40 p.m. EDT)

T+plus 28 minutes, 30 seconds. Centaur is maneuvering itself to the proper orientation for releasing ICO G1.

2039 GMT (4:39 p.m. EDT)

T+plus 27 minutes, 41 seconds. MECO 2. Main engine cutoff via guidance commanding is confirmed. Centaur has completed its second burn of the day. Release of the payload from the rocket is expected in about three minutes.

2038 GMT (4:38 p.m. EDT)

T+plus 26 minutes. The engine continues to fire smoothly, no issues reported.

2037 GMT (4:37 p.m. EDT)

T+plus 25 minutes. The vehicle is accelerating at just over 0.7 G's

2036 GMT (4:36 p.m. EDT)

T+plus 24 minutes, 30 seconds. This burn will last about five minutes.

2035 GMT (4:35 p.m. EDT)

T+plus 23 minutes, 20 seconds. The RL10 engine continues to burn well.

2034 GMT (4:34 p.m. EDT)

T+plus 22 minutes, 35 seconds. Ignition! The Centaur's single Pratt & Whitney Rocketdyne RL10 engine has re-ignited to accelerate the ICO G1 payload into a geosynchronous transfer orbit.

2033 GMT (4:33 p.m. EDT)

T+plus 21 minutes, 20 seconds. About one minute from engine start. Tank pressurization has started in preparation for ignition.

2032 GMT (4:32 p.m. EDT)

T+plus 20 minutes, 40 seconds. The rocket is 4,300 miles downrange from the launch pad, traveling at 17,833 mph.

2030 GMT (4:30 p.m. EDT)

T+plus 18 minutes. Centaur systems remain in good shape during this coast period.

2029 GMT (4:29 p.m. EDT)

T+plus 17 minutes, 30 seconds. A map of the rocket's planned ground track for today's launch is available here.

2028 GMT (4:28 p.m. EDT)

T+plus 16 minutes, 45 seconds. Centaur power bus and battery voltages are normal, tank pressures are stable. The stage is beginning to re-orient itself to the proper position for the next firing.

2026 GMT (4:26 p.m. EDT)

T+plus 14 minutes, 22 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 eight minutes before the RL10 engine re-ignites.

2025 GMT (4:25 p.m. EDT)

T+plus 13 minutes, 20 seconds. The rocket is traveling at 16,640 mph as it flies eastward across the Atlantic.

2024 GMT (4:24 p.m. EDT)

T+plus 12 minutes, 30 seconds. Two minutes to go in this first of two firings by the Centaur this afternoon.

2022 GMT (4:22 p.m. EDT)

T+plus 10 minutes, 15 seconds. The RL10 engine continues to fire normally, burning liquid hydrogen and liquid oxygen propellants.

2021 GMT (4:21 p.m. EDT)

T+plus 9 minutes, 30 seconds. About five minutes remaining in this firing of Centaur to reach a parking orbit around Earth.

2019 GMT (4:19 p.m. EDT)

T+plus 7 minutes, 35 seconds. Centaur power bus and battery voltages are normal.

2018 GMT (4:18 p.m. EDT)

T+plus 6 minutes, 35 seconds. Centaur engine readings look good as this 10-minute burn continues.

2017 GMT (4:17 p.m. EDT)

T+plus 5 minutes, 45 seconds. The rocket is 95 miles in altitude, 532 miles downrange and traveling over 12,000 mph.

2016 GMT (4:16 p.m. EDT)

T+plus 4 minutes, 50 seconds. The two-halves of the Atlas 5 rocket nose cone encapsulating the ICO spacecraft have separated.

2016 GMT (4:16 p.m. EDT)

T+plus 4 minutes, 34 seconds. Centaur has ignited. The RL10 engine is up and running at full thrust.

2016 GMT (4:16 p.m. EDT)

T+plus 4 minutes, 24 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.

2016 GMT (4:16 p.m. EDT)

T+plus 4 minutes, 16 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.

2015 GMT (4:15 p.m. EDT)

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

2014 GMT (4:14 p.m. EDT)

T+plus 2 minutes, 45 seconds. Atlas is 28 miles in altitude and 58 miles downrange, traveling at 4,900 mph.

2014 GMT (4:14 p.m. EDT)

T+plus 2 minutes, 22 seconds. The Aerojet-made solid rocket boosters have separated from the Atlas 5, having completed their job of adding a powerful kick at liftoff.

2013 GMT (4:13 p.m. EDT)

T+plus 93 seconds. Solid rocket booster burnout has occurred. But the spent motors will remain attached to the first stage for about 50 seconds, until the Atlas 5 reaches a point where the airborne dynamic pressure reduces to an allowable level for a safe jettison.

2013 GMT (4:13 p.m. EDT)

T+plus 60 seconds. One minute into the flight with the ICO G1 satellite. Atlas has passed Max Q and hit Mach 1.

2012 GMT (4:12 p.m. EDT)

T+plus 30 seconds. The 19-story rocket is thundering away from Cape Canaveral on the combined power of its RD-180 main engine and twin solid rocket boosters.

2012 GMT (4:12 p.m. EDT)

LIFTOFF! Liftoff of the Atlas 5 rocket with the commercial ICO G1 spacecraft, a mobile communications satellite to assist and entertain Americans on the go. And the vehicle has cleared the tower!

2011 GMT (4:11 p.m. EDT)

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

2011 GMT (4:11 p.m. EDT)

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

2011 GMT (4:11 p.m. EDT)

T-minus 1 minute. Now 60 seconds from liftoff of the AV-014 rocket and the ICO G1 satellite, the heaviest payload ever flown aboard an Atlas.

The massive communications spacecraft will beam live television directly to cars across the United States, help drivers with directions through enhanced navigation and relay messages for emergency roadside assistance. ICO will market this interactive media service starting next year.

Initially, customers with existing video display screens in cars and portable electronics can buy modem-like units with an antenna to receive the satellite transmissions. In the future, ICO foresees consumers purchasing devices with the technology already embedded.

2010 GMT (4:10 p.m. EDT)

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

2010 GMT (4:10 p.m. EDT)

T-minus 1 minute, 50 seconds. Liquid oxygen and liquid hydrogen propellant topping to the Centaur upper stage is being secured.

2010 GMT (4:10 p.m. EDT)

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

2010 GMT (4:10 p.m. EDT)

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

2009 GMT (4:09 p.m. EDT)

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.

2009 GMT (4:09 p.m. EDT)

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

2008 GMT (4:08 p.m. EDT)

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

2008 GMT (4:08 p.m. EDT)

T-minus 4 minutes and counting. Clocks have resumed for the final minutes of this afternoon's countdown to launch the Atlas 5 rocket carrying the ICO G1 communications spacecraft. Liftoff is targeted to occur at 4:12 p.m.

2006 GMT (4:06 p.m. EDT)

Countdown clocks will resume in two minutes. Now six minutes from launch.

2005 GMT (4:05 p.m. EDT)

The ULA launch director has given his approval to press onward with the countdown.

2005 GMT (4:05 p.m. EDT)

All systems are "go" to continue with the countdown for an on-time liftoff at 4:12 p.m.

2005 GMT (4:05 p.m. EDT)

Launch team polling is underway.

2004 GMT (4:04 p.m. EDT)

The ICO G1 spacecraft is switching to internal battery power for launch.

2000 GMT (4:00 p.m. EDT)

Coming up in five minutes, the launch team will be polled for a "go" or "no go" to proceed with the count.

1958 GMT (3:58 p.m. EDT)

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.

1957 GMT (3:57 p.m. EDT)

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

1956 GMT (3:56 p.m. EDT)

The fuel-fill sequence for the first stage main engine is complete. And the first stage liquid oxygen tank is reported at flight level.

1947 GMT (3:47 p.m. EDT)

Flight control system final preps are complete.

1946 GMT (3:46 p.m. EDT)

The first stage main engine fuel-fill sequence is beginning.

1942 GMT (3:42 p.m. EDT)

Thirty minutes to go. Today's launch will be the 14th for an Atlas 5 rocket and the 7th commercial mission since debuting in August 2002. The vehicle's flights have featured a very diverse payload list, including NASA space probes to Mars and Pluto, experimental U.S. military spacecraft, spy satellites and several commercial communications craft.

This flight is the will use the rocket's 421 configuration. The Common Core Booster first stage is outfitted with the RD-180 main engine, two solid rocket boosters are attached for added thrust at liftoff, the Centaur upper stage has a single RL10 cryogenic engine and the payload shroud is the four-meter diameter option.

1934 GMT (3:34 p.m. EDT)

The Centaur liquid hydrogen tank has reached flight level. The liquid oxygen tank achieved its flight level earlier.

1932 GMT (3:32 p.m. EDT)

Forty 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 on the ICO G1 satellite deployment mission remains scheduled for 4:12 p.m. EDT.

1922 GMT (3:22 p.m. EDT)

Range Safety is conducting the standard pre-launch check of the flight termination system.

1919 GMT (3:19 p.m. EDT)

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

1918 GMT (3:18 p.m. EDT)

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

1916 GMT (3:16 p.m. EDT)

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

1912 GMT (3:12 p.m. EDT)

Launch is now just 60 minutes away. At liftoff today, the Atlas 5 rocket will weigh nearly one million pounds. The ICO G1 spacecraft accounts for 14,625 pounds of that weight, making it the heaviest payload to ever fly aboard an Atlas vehicle. ICO eclipses the mark set by the Inmarsat 4-F1 communications satellite that weighed 13,138 pounds during its March 2005 launch.

1910 GMT (3:10 p.m. EDT)

The Centaur liquid hydrogen tank is 50 percent full. The cryogenic propellant will be consumed with liquid oxygen by the stage's Pratt & Whitney-made RL10 engine.

1908 GMT (3:08 p.m. EDT)

The first stage liquid oxygen tank is nearing about three-quarters full.

1859 GMT (2:59 p.m. EDT)

Chilldown of the liquid hydrogen system is now complete, allowing the super-cold fuel to begin filling the Centaur upper stage.

1853 GMT (2:53 p.m. EDT)

First stage liquid oxygen tank is 40 percent full. 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 25,000 gallons of RP-1 were loaded into the rocket prior to today's countdown.

1847 GMT (2:47 p.m. EDT)

The Centaur liquid oyxgen tank has reached flight level.

1845 GMT (2:45 p.m. EDT)

The Centaur engine chilldown has been initiated.

1842 GMT (2:42 p.m. EDT)

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

1842 GMT (2:42 p.m. EDT)

Now 90 minutes from the scheduled launch time. Weather continues to be favorable for launch. The ground winds are breezy but within limits and the scattered clouds appear to be thin and not a concern.

Activities remain on schedule for a liftoff at 4:12 p.m. EDT.

1839 GMT (2:39 p.m. EDT)

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

1838 GMT (2:38 p.m. EDT)

The Centaur liquid oxygen tank has reached the 80 percent level.

1836 GMT (2:36 p.m. EDT)

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 13,000 gallons of the cryogenic propellant.

1831 GMT (2:31 p.m. EDT)

Half of the Centaur liquid oxygen tank has been filled so far.

1829 GMT (2:29 p.m. EDT)

The chilldown conditioning of the systems for the first stage liquid oxygen tank have been completed. And a "go" has been given to begin pumping super-cold 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 about 50,000 gallons of cryogenic oxidizer for the RD-180 main engine.

1824 GMT (2:24 p.m. EDT)

The Centaur liquid oxygen tank is 20 percent full.

1815 GMT (2:15 p.m. EDT)

Filling of the Centaur upper stage with about 4,300 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 a pair of firings today to deliver the ICO G1 satellite into the desired orbit.

1808 GMT (2:08 p.m. EDT)

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.

1802 GMT (2:02 p.m. EDT)

T-minus 120 minutes and counting! The countdown clocks are running again for today's launch of the Atlas 5 rocket carrying the commercial ICO G1 mobile communications satellite.

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 4:12 p.m. EDT 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 a short time from now.

1759 GMT (1:59 p.m. EDT)

Fueling of the Atlas 5 rocket will be getting underway shortly. All console operators in the Atlas Spaceflight Operations Center reported a "ready" status during the pre-fueling poll just completed by the launch conductor. The launch director gave his approval as well.

Just prior to the poll, the ULA launch conductor briefed his team on countdown procedures before entering into the final two hours.

1737 GMT (1:37 p.m. EDT)

There is one COLA, or Collision Avoidance blackout period that will prohibit launch for during a few minutes during today's window. COLAs ensure the rocket is not launched at a time that would take its trajectory too close to another object already in space.

Today's COLA means the launch window will be broken into two parts -- 4:12 to 4:14 p.m. and then 4:23 to 5:12 p.m. EDT.

1732 GMT (1:32 p.m. EDT)

T-minus 2 hours and holding. The countdown has just entered the first of two planned holds over the course of the afternoon that will lead to the 4:12 p.m. EDT launch of Atlas. This initial pause lasts 30 minutes, giving the 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 last for 10 minutes.

1727 GMT (1:27 p.m. EDT)

Safety officials report the blast danger area surrounding the pad has been cleared of all personnel. The remainder of the countdown is considered hazardous, prompting the necessary protection around the launch complex.

1723 GMT (1:23 p.m. EDT)

The Range has performed the hold-fire checks to ensure safety officers have the capability of halting the countdown if a problem occurs.

1717 GMT (1:17 p.m. EDT)

The final members of the launch pad crew have finished their work and are leaving Complex 41 now.

1715 GMT (1:15 p.m. EDT)

Some scattered clouds are racing across the sky and winds have increased a bit. But conditions still look good for launch in about three hours.

The official launch time forecast calls for scattered clouds at 6,000 and 30,000 feet, a westerly wind of 18 gusting to 25 knots (limit is 29 knots) and a temperature around 70 degrees.

1650 GMT (12:50 p.m. EDT)

Crews report they have finished removing access platforms and handrails on the mobile launch platform and around the pad area. Workers will be clearing the Complex 41 within the next half-hour in advance of this afternoon's propellant loading.

1643 GMT (12:43 p.m. EDT)

Guidance system testing and the flight control countdown preps are complete. And a test with the Eastern Range of the C-band system, which is used for tracking the rocket as it flies downrange, just finished.

1637 GMT (12:37 p.m. EDT)

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

1612 GMT (12:12 p.m. EDT)

Now four hours from liftoff time. Work continues at the Complex 41 launch pad and inside the Atlas Spaceflight Operations Center. In the past few minutes, first stage propulsion and hydraulic preps were reported complete. Internal battery checks are beginning now.

Today's launch of the Atlas 5 rocket will be the second flight of the vehicle's 421 configuration, which is distinguished by the combination of a four-meter payload fairing, two solid rocket boosters and a single-engine Centaur upper stage. The first use of this version occurred last October with the launch of the Air Force's Wideband Global SATCOM satellite.

Depending on a payload's weight, mission planners add strap-on solid boosters to the Atlas 5 to incrementally increase the amount of cargo the rocket can carry.

For the Atlas 5's 400-series, up to three solids can be used. The 500-series is capable of flying with as many as five, such as the launch of NASA's New Horizons space probe bound for Pluto.

The Russian RD-180 first stage main engine can accomplish the entire job of steering the Atlas 5 during launch, thus the solid boosters feature simple, fixed nozzles.

Each Aerojet-built SRB stands 67 feet tall, has a diameter of just over five feet and weighs about 100,000 pounds at launch. The slender white rockets have a lightweight graphite epoxy casing with an erosion-resistant insulation. The solid fuel is high-performance class 1.3 HTPB propellant.

Atop the booster is an aerodynamically-shaped graphite epoxy nose fairing. Each motor has forward and aft attachment structures to the Atlas 5's first stage. The motor nozzle is carbon-phenolic.

The motor burns for 90 seconds, producing a maximum thrust of approximately 400,000 pounds and an average around 250,000 pounds.

1540 GMT (11:40 a.m. EDT)

It's a blue sky day here at Cape Canaveral, with a gentle breeze and warm temperatures. The countdown is proceeding ontime and without trouble. Liftoff of the Atlas 5 rocket remains on track for 4:12 p.m.

1512 GMT (11:12 a.m. EDT)

Now five hours from launch. The countdown began as scheduled this morning, officials are not reporting any significant problems and the weather is looking great right now.

Today's half-hour flight of the Atlas 5 rocket to deploy the ICO G1 mobile communications spacecraft into geosynchronous transfer orbit begins with a 4:12 p.m. EDT blastoff from Cape Canaveral's Complex 41 pad.

The RD-180 engine ignites 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 twin strap-on solid rocket boosters are lit at T+plus 0.8 seconds, leading to liftoff of the 19-story Atlas vehicle at T+plus 1.1 seconds.

The Aerojet-made solid boosters will burn for about 90 seconds to assist the RD-180 in propelling the rocket skyward. The SRB casings remain attached to the first stage for another 50 seconds until the rocket reaches a lower dynamic pressure region of flight.

After the spent boosters are jettisoned, the kerosene-fueled first stage will continue to fire until T+plus 4 minutes, 15 seconds. The bronze stage separates about six seconds later, leaving the hydrogen-fueled Centaur upper stage to ignite for a 10-minute burn that will inject itself and ICO G1 into a preliminary orbit with a low point of 104 miles, a high point of 472 miles and inclination of 27.75 degrees.

Centaur completes its first burn over the Central Atlantic Ocean and enters a brief eight-minute coast. The Pratt & Whitney RL10 cryogenic engine then restarts for a five-minute firing to propel the ICO spacecraft into a highly elliptical geosynchronous transfer orbit stretching from 116 miles at its lowest point to 22,323 miles at its highest and inclined 22.7 degrees to the equator.

Release of the ICO satellite from the rocket to complete the launch is expected a few seconds before T+plus 31 minutes.

"It's the shortest coast mission for our Centaur stage at about eight minutes. And it is the heaviest spacecraft that we've flown on Atlas 5 at about 6.6 metric tons, so quite a healthy commercial spacecraft," said David Markham, president of Lockheed Martin Commercial Launch Services.

A full timeline of launch events is available here.

Ground controllers will maneuver the satellite into a circular geostationary orbit to begin testing its interactive mobile communications services by late summer. The craft's operational location will be 92.85 degrees West longitude over the equator.

1330 GMT (9:30 a.m. EDT)

The odds of having acceptable weather conditions at launch time have improved in the latest forecast issued this morning. There's now a 70 percent chance of good weather, with gusty winds and thick clouds still the main concerns.

See the updated forecast here.

1312 GMT (9:12 a.m. EDT)

Countdown clocks have started ticking for today's planned 4:12 p.m. EDT liftoff of the Atlas 5 rocket with the ICO G1 mobile communications satellite from Cape Canaveral, Florida.

The launch team is powering up the rocket and will soon begin standard pre-flight tests. Crews at the pad will make preparations to systems and equipment before the site is cleared of all personnel shortly before 1:30 p.m.

A planned half-hour hold begins at 1:32 p.m. when the count reaches T-minus 120 minutes. Near the end of the hold, the team will be polled at 1:57 p.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 2:19 p.m., followed by the first stage filling around 2:32 p.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 3:58 p.m. That 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.

0405 GMT (12:05 a.m. EDT)

A collection of photos showing the Atlas 5 rocket rolling out to the launch pad Sunday morning is posted here.

SUNDAY, APRIL 13, 2008

A massive communications satellite that will beam live television directly to cars and help drivers with directions launches into space Monday afternoon aboard an Atlas 5 rocket.

Liftoff from Cape Canaveral's Complex 41 is scheduled for 4:12 p.m. EDT, the opening of a 60-minute launch opportunity.

Weighing 14,625 pounds, the commercial ICO G1 mobile communications spacecraft is the heaviest payload ever launched by an Atlas rocket. Built by Space Systems/Loral, the craft stands over 27 feet tall, features a 39-foot-diameter mesh reflector antenna that will be unfurled in space and a pair of power-generating solar wings to span over 100 feet tip-to-tip once extended in orbit.

The satellite and a network of ground repeaters will enable ICO to market an interactive media service combining live TV, enhanced navigation and emergency assistance across the United States starting next year.

"It's a mass consumer audience that we are going after, people who want full content and connectivity in a mobile environment," said Christopher Doherty, ICO's vice president for public relations.

"Mobile families, people who are driving the mini-vans and SUVs with kids in the back seat, we see a big opportunity in the RV market, same with boating, the taxicab and limo sector, truckers too."

Initially, customers with existing video display screens in cars and portable electronics can buy modem-like units with an antenna to receive the satellite transmissions. In the future, ICO foresees consumers purchasing devices with the technology already embedded.

Between 10 and 15 channels of live television is planned for the system, including a lineup of news, sports, kids and general entertainment programming.

"Unlike mobile television that goes to cell phones, which are kind of small screens, we think mobile video will really take off when people can see it on a larger screen and they'll be willing to watch more of it when it's a better quality experience," Doherty said.

Emergency messaging via the satellite will extend beyond the reach of current assistance systems, ICO says.

"Roadside assistance will be different because coverage will be nationwide since it's satellite-based. Today's systems are reliant on cellular networks, which cover 99 percent of the population but only about a two thirds of the geography. So in remote areas it will work," Doherty said.

And ICO promotes its "intelligent" navigation system that combines current features, such as traffic alerts and destination information, with the ability to pre-program activities along the route.

Pricing details for the user equipment aren't available yet, Doherty said, but subscription fees for the service are expected between $15 and $25 a month.

Extensive testing of the mobile services should start this summer in Las Vegas and Raleigh, North Carolina. The two distinctly different locales were strategically selected to determine how the satellite and ground repeater system works within the urban environment and tall buildings of Las Vegas and the hilly terrain of an American city like Raleigh, Doherty explained.

The ICO G1 satellite also has the capability to provide voice communications along with the mobile offerings.

"The satellite can do a variety of things," Doherty said. "It's actually the first commercial satellite to have what's called ground-based beam forming, both in the transmit and the receive directions. The satellite is specifically designed with a 12-meter reflector so that it can communicate to smaller mobile and portable devices.

"While the bundled service of navigation, television and emergency communication is what we are going to (test) once the satellite is up and running, because the beam-forming is based on the ground we can pretty much run any variety of technologies off this satellite."

The combined cost of the ICO G1 satellite, its development, the Atlas 5 rocket and insurance totals $500 million.

1538 GMT (11:38 a.m. EDT)

The mobile launch platform has been secured in place at the pad following this morning's rollout from the assembly building.

1535 GMT (11:35 a.m. EDT)

See the full launch weather forecast here.

1526 GMT (11:26 a.m. EDT)

ON THE PAD! The Atlas 5 rocket has arrived at the Complex 41 launch pad for liftoff less than 29 hours from now to deliver into orbit the commercial ICO G1 communications spacecraft.

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 this afternoon, the undercarriages used to move the mobile platform will be disconnected and the "trackmobiles" pulled free. Crews will secure the rocket and pad for the night. The launch countdown commences at 9:12 a.m. EDT tomorrow, some seven hours before liftoff time.

1510 GMT (11:10 a.m. EDT)

The Atlas 5 is continuing its trek to the pad under mostly cloudy skies.

The rocket was assembled inside the VIF starting with erection of the bronze first stage onto the mobile launch platform. Some photos of the event are posted here.

The first stage, known as a Common Core Booster, is 106 feet long and 12.5 feet in diameter. It is equipped with the kerosene-fueled RD-180 main engine.

Later, the hydrogen-fueled Centaur upper stage with its RL10 engine was hoisted into position and two strap-on solid propellant boosters were attached to the first stage.

The Centaur is about 40 feet long and 10 feet in diameter. Each solid rocket booster is 67 feet long and 5 feet in diameter.

Today marks the second trip to the pad for this rocket. On March 24, the vehicle was rolled out for a countdown dress rehearsal. A full launch day simulation, including the loading of propellants into the rocket stages, successfully occurred on March 25. The rocket was returned to the VIF on March 26.

Meanwhile, the ICO G1 spacecraft arrived at Cape Canaveral from its Space Systems/Loral manufacturing factory on February 28. It underwent final pre-flight preparations at the Astrotech facility near Titusville. After being encapsulated in the nose cone shroud, the satellite was brought to the VIF for hoisting atop the Atlas on April 2.

Photos showing the two-halves of the shroud being placed around the satellite and the arrival at the VIF are posted here.

The combined operations between the rocket and payload were accomplished over the following week, leading to the final launch readiness reviews on Friday that concluded with approval to proceed with today's rollout.

1455 GMT (10:55 a.m. EDT)

ROLLOUT BEGINS! The United Launch Alliance Atlas 5 rocket just began a slow half-hour drive from the 30-story Vertical Integration Facility to Cape Canaveral's Complex 41 pad for tomorrow afternoon's liftoff.

A pair of specially-made "trackmobiles" are pushing the Atlas 5 rocket's 1.4-million pound mobile launching platform along rail tracks for this 1,800-foot trip.

1410 GMT (10:10 a.m. EDT)

The rollout has not yet started. The Atlas team hopes to get the rocket on its way to the launch pad later this morning.

The latest weather outlook for Monday's launch opportunity calls for scattered clouds at 4,000 and 30,000 feet, westerly winds from 280 degrees at 16 gusting to 24 knots and a temperature around 70 degrees F. There is a 60 percent chance of meeting the launch weather rules due to winds and thick clouds.

1300 GMT (9:00 a.m. EDT)

Activities are underway inside and surrounding the Vertical Integration Facility this morning as ground teams ready the Atlas 5 rocket and its mobile launch platform convoy for rollout to the pad.

About an hour from now, the rocket will be transported by rail about one-third-of-a-mile from the assembly building to the Complex 41 pad.

Launch remains targeted for Monday at 4:12 p.m. EDT (2012 GMT).

SATURDAY, APRIL 12, 2008

An Atlas 5 rocket with a mobile communications satellite aboard will journey to the launch pad tomorrow morning, traveling from the vertical assembly building to its seaside complex at Cape Canaveral for Monday afternoon's scheduled blastoff.

Final launch readiness reviews were completed on Friday and crews were planning to rest today.

"The satellite looks great, the rocket looks great," David Markham, president of Lockheed Martin Commercial Launch Services, said Friday.

Sunday's rollout is expected to begin around 10 a.m. as countdown activities get underway for the first commercial Atlas flight in nearly two years.

The ICO G1 satellite launching atop the rocket was built to provide live television, enhanced navigation and roadside assistance to mobile users across the United States.

"This is a vitally important launch to ICO and we're proud to have been selected as the launch services partner," Markham said. "This launch also will demonstrate the flexibility of the Atlas program that can be applied to the commercial market as we continue to seek one to two commercial customers per year."

The last five Atlas 5 launches carried payloads for the U.S. government.

Monday's launch is scheduled for 4:12 p.m. EDT (2012 GMT). A 60-minute window is available through 5:12 p.m. to get the rocket airborne if problems or weather interfere with the countdown.

Air Force meteorologists are predicting a 60 percent chance of acceptable conditions at launch time. Strong winds and the thickness of cloud cover are the main worries.

See today's updated forecast here.

FRIDAY, APRIL 11, 2008

The latest launch weather forecast issued this morning is posted here.

THURSDAY, APRIL 10, 2008

A United Launch Alliance Atlas 5 rocket is scheduled to launch the ICO G1 commercial communications satellite on Monday afternoon from Cape Canaveral.

The rocket will fly in the 421 vehicle configuration with a four-meter fairing, two solid rocket boosters and a single-engine Centaur upper stage.

Liftoff is targeted for 4:12 p.m. EDT at the opening of a one-hour launch window that extends through 5:12 p.m. EDT (2012-2112 GMT).

The rocket will be rolled from the Vertical Integration Facility to the Complex 41 launch pad atop its mobile platform on Suunday morning.

The weather forecast predicts a 60 percent chance of acceptable conditions on launch day. Winds and clouds are the main concerns. See the full forecast here.