The mystery communications spacecraft launched aboard an Atlas 5 rocket from Cape Canaveral earlier this month -- and pictured in this story -- has arrived in a geostationary orbit that views the Middle East, hobbyist satellite trackers report.

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A mysterious spacecraft whose mission is cloaked in secrecy left Cape Canaveral atop the hard-to-miss roar of its Atlas 5 rocket and then revealed a major clue about itself while cruising above a satellite-tracking hobbyist a short time later.

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Stunning launch photos from cameras positioned at the pad are must-see! Check them out here.

"This launch helps to ensure that vital communications will continue to bolster our nation's capabilities and showcases why the 45th Space Wing is the world's premiere gateway to space," said Brig. Gen. Edward L. Bolton, Jr., 45th Space Wing commander at the Cape.

"The 45th Space Wing is in the midst of a very busy launch season and during our Operational Readiness Inspection. We are looking forward to many more successful missions before the year's end," General Bolton said. "This is perhaps the cleanest countdown we've seen this year."

"This launch was an outstanding achievement for the entire Atlas team," said Staff Sgt. Brad Tavares, Atlas 5 Mission Assurance Technician. "It makes me extremely proud to be a part of the success of this mission and I look forward to providing continued mission assurance for all future launches."

Beautiful views of tonight's Atlas 5 rocket as seen from Playalinda Beach have been posted here.

"ULA is proud to have played a critical role in the success of this important mission," said Mark Wilkins, ULA vice president of Atlas programs. "Close teamwork with Lockheed Martin and the U.S. Air Force's 45th Space Wing at Cape Canaveral made today's launch possible."

T+plus 119 minutes, 27 seconds. SPACECRAFT SEPARATION! The Centaur upper stage has deployed the PAN payload into orbit follow today's launch from Cape Canaveral.

Little is known about this communications satellite, called PAN, or what government agency it will support.

"Lockheed Martin is the prime contractor for the PAN mission, which includes a commercial-based satellite and launch system solution for the U.S. government," the company said in a statement.

"Additional details of the mission are of a classified nature."

T+plus 118 minutes, 35 seconds. Centaur is in the spacecraft deploy position.

T+plus 118 minutes. Centaur has hit the planned orbital parameters.

T+plus 117 minutes. Centaur is maneuvering itself to the proper orientation for releasing the payload.

T+plus 116 minutes, 32 seconds. MECO 2. Main engine cutoff confirmed. Centaur has completed its second burn.

T+plus 116 minutes. This is a planned 86-second burn by the Centaur's single Pratt & Whitney Rocketdyne RL10 engine.

T+plus 115 minutes, 30 seconds. For the second time in this launch, the engine is burning well.

T+plus 115 minutes, 5 seconds. Ignition and full thrust! The Centaur's single Pratt & Whitney Rocketdyne RL10 engine has re-ignited to accelerate the PAN payload into the planned deployment orbit.

T+plus 114 minutes. Centaur is about 9,000 miles in altitude.

T+plus 112 minutes, 30 seconds. Centaur has reached the orientation for the upcoming burn.

T+plus 108 minutes, 30 seconds. The rocket is performing its turn to the proper position for the next engine firing.

T+plus 102 minutes. Another roll reversal is underway.

T+plus 90 minutes. All systems remain nominal.

T+plus 80 minutes. Centaur is operating well wth good battery voltages and tank pressures. The vehicle is completing a roll reversal as planned.

We have posted photos of the launch taken from the Kennedy Space Center press site here.

T+plus 60 minutes. The upper stage continues in its thermal conditioning roll while quietly coasting in the parking orbit.

T+plus 30 minutes. Centaur's onboard systems remain stable in this coast period.

T+plus 18 minutes, 15 seconds. The parking orbit parameters are right on the money, ULA says.

T+plus 17 minutes, 28 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 an hour and 38 minutes before the RL10 engine re-ignites.

T+plus 15 minutes, 30 seconds. Centaur systems remain in good shape.

T+plus 12 minutes, 30 seconds. About five minutes remain in this burn of Centaur.

T+plus 11 minutes, 45 seconds. Good chamber pressures on the RL10.

T+plus 9 minutes. The RL10 continues to perform well, burning liquid hydrogen and liquid oxygen propellants.

T+plus 7 minutes, 45 seconds. Centaur is 164 miles in altitude, 897 miles downrange and traveling at 12,671 mph.

T+plus 7 minutes. All systems reported stable as the Centaur fires to reach an initial Earth orbit.

T+plus 5 minutes, 35 seconds. Centaur engine readings look good as this 13-minute burn continues.

T+plus 5 minutes, 15 seconds. Now 91 miles in altitude, 381 miles downrange from the launch pad, traveling at 11,517 mph.

T+plus 4 minutes, 33 seconds. The two-halves of the Atlas 5 rocket nose cone encapsulating the spacecraft have separated.

T+plus 4 minutes, 24 seconds. Centaur has ignited! The RL10 engine is up and running at full thrust.

T+plus 4 minutes, 15 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, 5 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, 55 seconds. The RD-180 main engine continues to fire normally, burning a mixture of highly refined kerosene and liquid oxygen.

T+plus 3 minutes, 40 seconds. The rocket is 38 miles in altitude, some 103 miles downrange and traveling over 7,800 mph already.

T+plus 3 minutes. RD-180 is performing well as the rocket climbs away from the planet.

T+plus 2 minutes. Atlas is flying due east from the Cape.

T+plus 85 seconds. Mach 1.

T+plus 60 seconds. One minute into the ascent. It will take an hour and 59 minutes for the two-stage rocket to deploy the satellite into the desired orbit.

T+plus 30 seconds. The Atlas 5 rocket is thundering away from Cape Canaveral on the power of the RD-180 main engine carrying a secretive communications satellite built by Lockheed Martin for the U.S. government.

T+plus 15 seconds. And the vehicle has cleared the towers at Complex 41.

LIFTOFF! Liftoff of the Atlas 5 rocket and Lockheed Martin's commercial opportunity to provide communications satellite services to the U.S. government.

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. Now 60 seconds from launch.

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

T-minus 1 minute, 50 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 this afternoon's countdown to launch the Atlas 5 rocket carrying the PAN payload for Lockheed Martin. Liftoff is set to occur at 5:35 p.m.

Countdown clocks will resume in one minute.

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

Polling of the team by Atlas launch conductor just occurred. All systems are reported "go" to continue with the countdown for liftoff at 5:35 p.m.

The launch team is being polled for a "go" or "no go" to proceed with the count.

Now 10 minutes away from the scheduled launch time.

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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. Today's launch opportunity stretches from 5:35 to 7:44 p.m. EDT.

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.

Weather conditions still look great for launch at 5:35 p.m. EDT.

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

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

• The 17th launch of an Atlas 5 vehicle since 2002
• The 16th Atlas 5 to occur from Cape Canaveral
• The 8th Atlas 5 to fly in the 401 configuration
• The 9th Atlas 5 under United Launch Alliance
• The 8th commercial launch for the Atlas 5 family

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 remains scheduled for 5:35 p.m. EDT.

The launch team is going through normal post-fueling valve and system checks.

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

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

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

The Centaur liquid hydrogen tank is 70 percent loaded so far. The cryogenic propellant will be consumed with liquid oxygen by the stage's Pratt & Whitney-made RL10 engine.

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 5:35 p.m. EDT.

If you are heading out to Titusville or the beach to watch the launch, sign up for our Twitter feed to get occasional countdown 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.)

About three-quarters of the first stage liquid oxygen tank has been loaded.

Centaur's liquid hydrogen tank is 20 percent full.

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 first stage liquid oxygen tank is 50 percent full.

The Centaur engine chilldown sequence is being initiated.

First stage liquid oxygen tank is passing the 30 percent mark. 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 earlier.

Upper stage liquid oxygen has reached flight level.

Now 90 minutes from liftoff.

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

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

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.

The Centaur liquid oxygen tank is three-quarters full now.

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

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 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 about 50,000 gallons of cryogenic oxidizer for the RD-180 main engine.

The Centaur liquid oxygen tank has reached the 20 percent level.

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 send the PAN payload on its way.

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.

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 5:35 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.

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 ULA launch director voiced his approval as well. Loading of cryogenic liquid oxygen and liquid hydrogen into the Atlas 5 rocket will be getting underway a short time from now.

Atlas launch conductor is briefing his team on procedures before entering into the final two hours of the countdown. A readiness check of the team members is next.

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 5:35 p.m. EDT launch of the Atlas-Centaur 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 hold-fire checks have been performed to ensure safety officers have the capability of halting the countdown if a problem occurs.

Clearing of personnel from the launch pad for rest of the countdown has started.

The latest check of the weather shows current conditions are favorable and the outlook is very promising this afternoon.

While the Atlas team is counting down, the space shuttle Discovery is scheduled to undock from the International Space Station at 3:26 p.m. EDT. You can follow that live in our Mission Status Center by clicking here.

The countdown is progressing through its initial hours under sunny skies. After the rocket was powered up, the guidance system test kicked off. Safety checks and flight control preps, as well as work to ready the propellant systems are underway too.

The weather forecast for today's launch opportunity has improved significantly. The odds of acceptable conditions now stand at 70 percent, up from the earlier outlook of just 40 percent.

"A low pressure system off the Carolina coast continues to transport in dryer air over the peninsula resulting in a reduced threat of afternoon and evening thunderstorms for launch day," the weather team reports.

"Weak westerly steering level winds will result in slow migration of interior thunderstorms toward the east coast. Upper level winds will transport anvil clouds from interior thunderstorms toward the east coast. The seabreeze is expected to develop near noon and serve as the focus for limited thunderstorm activity as it pushes slowly to the west.

"The primary concerns for launch day are anvil clouds, cumulus clouds, and lightning.

"In the event of a 24-hour delay, the remnants of a frontal boundary to the south begins migrating back north increasing moisture and the threat of showers and thunderstorms. The primary concerns for a 24-hour delay are thick clouds, anvil clouds, cumulus clouds, and lightning."

Although its payload is cloaked in secrecy, you won't be able to miss the United Launch Alliance Atlas 5 rocket making a thunderous blastoff from Cape Canaveral at 5:35 p.m. EDT today.

The countdown clocks started ticking at 10:35 a.m. EDT as the launch team began powering up the rocket to commence standard pre-flight tests. Over the next 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 2:40 p.m.

A planned half-hour hold begins at 2:55 p.m. when the count reaches T-minus 120 minutes. Near the end of the hold, the team will be polled at 3:22 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 3:42 p.m., followed by the first stage filling around 3:55 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 5:21 p.m. That 10-minute pause will give everyone a chance to finish any late work and assess the status of the rocket, payloads, Range and weather before proceeding into the last moments of the countdown for liftoff at 5:35 p.m. EDT.

And a reminder that if you will be away from your computer but would like to receive occasional countdown updates, sign up for our Twitter feed to get text 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.)

A collection of beautiful photos showing the Atlas 5 rocket rolling out to the launch pad and standing poised at sunset is posted here.

The Atlas 5 rocket carrying a secretive communications satellite built by Lockheed Martin for the U.S. government was rolled out to its launch pad at Cape Canaveral this morning in preparation for blastoff Tuesday evening.

The United Launch Alliance-made rocket began the brisk half-hour drive from the 30-story Vertical Integration Facility to the Complex 41 pad around 10:06 a.m. EDT. A pair of specially-made "trackmobiles" hauled the Atlas 5 rocket's 1.4-million pound mobile launching platform along rail tracks for the 1,800-foot trip.

The two-stage launcher was put together inside the assembly hangar in July. The Atlas 5 is designed to spend minimal time at the launch pad, which does not include a service gantry like other sites.

The two mobile trailers connected to the launching platform that were part of the convoy during this morning's rollout 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.

Ground crews will secure the rocket for the evening. The launch countdown commences at 10:35 a.m. EDT tomorrow, leading toward a liftoff at 5:35 p.m. EDT.

Little is known about the spacecraft being launched or the mission it will perform in orbit. The craft is called PAN.

"Lockheed Martin is the prime contractor for the PAN mission, which includes a commercial-based satellite and launch system solution for the U.S. government," the company said in a statement.

"Additional details of the mission are of a classified nature."

The lengthy launch window will extend from 5:35 to 7:44 p.m. EDT, and officials may need such a broad shot to find a hole in the weather. Air Force meteorologists are predicting a 40 percent chance that conditions will permit a liftoff on Tuesday due to concerns with thunderstorm clouds and lightning. And if the flight is pushed back to Wednesday for some reason, the odds worsen to just 30 percent of launching.

"A developing low pressure system off the Carolina coast results in dryer air over the peninsula today. A remnant trough of low pressure east of the Florida peninsula with an upper level trough in the Gulf of Mexico persists through launch week. Moisture gradually increases on launch day with ample moisture in place on Wednesday," forecasters say.

"Increasing moisture coupled with the upper level trough will result in afternoon and evening thunderstorms over the peninsula. Weak westerly steering level winds through mid week will result in slow migration of interior thunderstorms toward the east coast. Upper level winds will transport anvil clouds from interior thunderstorms toward the east coast," the latest outlook says.

"On launch day, increasing moisture, afternoon heating, and the influence of the upper level trough results in afternoon and evening thunderstorms. The seabreeze is expected to develop near noon and serve as the focus for developing thunderstorms as it pushes slowly to the west. Upper level steering winds will cause thunderstorms to slowly drift back toward the east coast. Westerly anvil level winds are a threat to transport anvil clouds back toward the east coast.

"The primary concerns for launch day are anvil clouds, cumulus clouds, and lightning.

"In the event of a 24-hour delay, increasing moisture and gradual strengthening of upper level winds will transport interior thunderstorms and anvil clouds back to the east coast. The primary concerns for a 24-hour delay are anvil clouds, cumulus clouds, and lightning."

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

An Atlas 5 rocket with the classified PAN spacecraft for Lockheed Martin is scheduled for launch from Cape Canaveral on Tuesday evening. Final pre-flight readiness reviews were completed today and gave concurrence to proceed with liftoff during a launch window extending from 5:35 to 7:44 p.m. EDT.

Rollout of the 19-story vehicle from its assembly building to the pad at Complex 41 will occur Monday morning.

Check back later for complete live coverage of the launch.