• The 618th launch for Atlas program since 1957
• The 207th mission for the Centaur upper stage
• The 184th use of Centaur by an Atlas rocket
• The 290th Atlas to occur from Vandenberg AFB since 1959
• The 39th Atlas to use Space Launch Complex 3
• The 6th Atlas 5 to occur from Vandenberg
• The 36th launch of an Atlas 5 since 2002
• The 57th Evolved Expendable Launch Vehicle flight
• The 28th Atlas 5 under United Launch Alliance
• The 24th 400-series flight of the Atlas 5
• The 16th Atlas 5 to fly in the 401 configuration
• The 9th NASA launch on Atlas 5
• The 8th Landsat launch
• The 3rd Landsat built by Orbital Sciences
• The 1st Landsat launched on an Atlas rocket
• The second Atlas launch of 2013

The stage is 41.5 feet in length and 10 feet it diameter. It also houses the navigation unit that serves as the rocket's guidance brain.

It is equipped with the RD-180 liquid-fueled main engine. This liquid oxygen/kerosene powerplant is a two-thrust chamber, two-nozzle engine.

As the CCB's name suggests, the stage is common and is used in all the various configurations of the Atlas 5 family. The booster stage is 106.6 feet long and 12.5 feet diameter.

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.

But this cargo, the three-ton Landsat spacecraft headed for polar orbit is satisfied with the lifting power of the basic Atlas 5 design.

The vehicle will fly southward away from Vandenberg along an initial flight azimuth of 186.4 degrees. Without using an solid motors, however, the rocket won't produce a smokey contrail off the pad.

The Russian RD-180 first stage main engine will ignite at T-minus 2.7 seconds, roaring to full power while undergoing a check to ensure its vital signs are healthy.

Rising off the pad in a slow, majestic fashion, the 19-story Atlas vehicle will deliver nearly a million pounds of ground-shaking thrust for the mid-morning departure.

Four-and-a-half minutes into the flight, staging will occur as the Centaur ignites and the nose cone is jettisoned. The Centaur will burn for about 11 minutes, achieving a preliminary parking orbit of approximately 90 by 373 nautical miles.

The vehicle coasts in that elliptical perch for 55 minutes before the Centaur is restarted over the Middle East to circularize the orbit.

Deployment of Landsat to complete the launch sequence is expected an hour and 18 minutes after liftoff while flying over Sweden.

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And the chilldown conditioning of liquid hydrogen propellant lines 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 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 loaded into the stage a little later in the countdown.

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.

Clocks have one more hold scheduled 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. local time (1:02 p.m. EST; 1802 GMT) from Vandenberg Air Force Base, California.

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

Topped with the high-energy Centaur upper stage, Atlas rockets have been used since the 1960s to dispatch ground-breaking missions for NASA, including the Surveyors to the Moon, Mariner flights to Mars, Venus and Mercury, and the Pioneers that were the first to visit Jupiter and beyond.

In its newest era, the Atlas 5 rocket sent the Mars Reconnaissance Orbiter to the red planet in 2005, propelled the New Horizons probe toward Pluto and the solar system's outer fringes in 2006, doubled up with the dual Lunar Reconnaissance Orbiter and LCROSS impactor to the Moon in 2009, hurled Juno to Jupiter in August 2011, dispatched the car-sized Curiosity rover on the Mars Science Lab mission in November 2011, and deployed a pair of harden probes in the heart of Earth's radiation belts last August.

Today marks the 36th flight for Atlas 5, born of the Air Force's competition to develop next-generation Evolved Expendable Launch Vehicles. In its previous 35 missions since debuting in August 2002, the tally shows 11 flights dedicated to the Defense Department, 9 commercial missions with communications spacecraft, eight for NASA and seven with spy satellites for the National Reconnaissance Office.

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.

Workers have left the pad area in advance of this morning's propellant loading and launch of the Atlas 5 rocket.

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The ground crews are getting the gantry's doors closed, plus finishing the final buttoning up of pad equipment over before all workers clear the pad for the remainder of the countdown.

Today's launch will be the sixth Atlas 5 rocket to fly from Vandenberg's Space Launch Complex 3-East pad. The site underwent an extensive overhaul, with construction occurring in 2004 and 2005, to accommodate the larger and more powerful Atlas 5 family of rockets. Some of the major modifications included:

• 30-foot extension to mobile service tower
• 20-foot exhaust duct depth increase
• 250-ton Fixed Launch Platform installed
• Significant ambient and cryogenic fluid ground system modifications
• Complete replacement of the Ground Command/Control/Communication system
• New and refurbished Launch Control/Mission Support Centers

This is the 39th Atlas overall to fly from SLC 3 throughout Vandenberg history.

The structure's internal crane was instrumental in bringing the rocket stages and payload together. And now the fully assembled Atlas 5 has been unveiled for its 36th launch, the sixth to originate from Vandenberg.

"LDCM is a really important mission that will make the satellite a critical and extremely valuable national asset. The LDCM will continue the monitoring of the global land surface begun by Landsat 1 40 years ago," said Jim Irons, the satellite's project scientist.

Once commissioned, LDCM will be renamed Landsat 8.

As the countdown gets started, the launch team will power up the rocket to conduct standard pre-flight tests and ready the vehicle for this Earth-resources satellite deployment mission for NASA and the U.S. Geological Survey.

Rollback of the mobile service tower from around the rocket is expected around 5:22 a.m. local (8:22 a.m. EST). Once the gantry is removed, crews at the pad will make preparations to systems and equipment before the site is cleared of all personnel for fueling.

A planned 30-minute hold begins when the count reaches T-minus 120 minutes at 7:22 a.m. local time (10:22 a.m. EST). With a few minutes remaining in the hold, the team will be polled to verify all is in readiness to start loading propellant into the rocket for launch.

Supercold liquid oxygen begins flowing into the Centaur upper stage around 8:09 a.m. local (11:09 a.m. EST), followed by the Atlas first stage. Liquid hydrogen fuel loading for Centaur will be completed a short time later.

A final hold is scheduled at 9:48 a.m. when clocks hit the T-minus 4 minute mark. That will give the team 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.

Liftoff remains targeted for 10:02 a.m. local time (1:02 p.m. EST; 1802 GMT).

"LDCM will extend and improve upon the Landsat record of landscape change. The resulting observations and information will be critical to managing increasing demands on land resources and preparing for inevitable changes to the global land surface," said Jim Irons, the satellite's project scientist.

It will be the seventh Landsat put into operation when commissioning is finished in about 100 days, continuing a 40-year record of monitoring environmental change.

"For decades, Landsat has played an important part in NASA's mission to advance Earth system science. LDCM promises to extend and expand that capability," said Michael Freilich, director of the Earth Science Division in the Science Mission Directorate at NASA Headquarters. "USGS's policy of offering free and open access to the phenomenal 40-year Landsat data record will continue to give the United States and global research community a better understanding of the changes occurring on our planet."

The countdown begins Monday at 2:22 a.m. local (5:22 a.m. EST; 1022 GMT) at the Space Launch Complex 3-East pad in preparation for liftoff at 10:02 a.m. local (1:02 p.m. EST; 1802 GMT) from Vandenberg Air Force Base in California.

United Launch Alliance initiated work on the LDCM mission four years ago and started building the Atlas-Centaur vehicle nearly two years ago, said Vernon Thorp, ULA's program manager for NASA missions.

It will be NASA's first Atlas launch from the West Coast since 1999 and the first-ever California use of the Atlas 5 by the space agency.

"LDCM will continue to describe the human impact on Earth and the impact of Earth on humanity, which is vital for accommodating seven billion people on our planet," said project manager Ken Schwer.

Weather forecasters continue to predict perfect conditions at liftoff time, with just a few high cirrus clouds, unrestricted visibility and light winds.

"The entire LDCM team is really excited to be launching our new observatory in just a few days. A lot of people from all over the country have done an awesome job in getting our spacecraft ready to fly," said David Jarrett, the LDCM program executive from NASA Headquarters.

Officials gathered this afternoon for a follow-up portion of the Launch Readiness Review to close out a pair of technical topics that needed more time and were not put to rest during the original LRR on Friday morning. Ordnance connections had been completed as well, NASA says, allowing managers to assess the overall schedule at the pad.

At the end of today's meeting, the launch team was given approval to begin the countdown on Monday at 2:22 a.m. local (5:22 a.m. EST; 1022 GMT). The mobile service gantry will be retracted to unveil the 19-story-tall rocket at 5:22 a.m. local, followed by the start of fueling operations just after 8 a.m.

Liftoff is scheduled for 10:02 a.m. local (1:02 p.m. EST; 1802 GMT) from Space Launch Complex 3-East at Vandenberg Air Force Base, California.

The morning's launch window will extend for 48 minutes to 10:50 a.m. local time.

Weather forecasters continue to predict favorable conditions.

The mission comes less than two weeks after an Atlas 5 rocket launched from Cape Canaveral in Florida to deploy NASA's Tracking and Data Relay Satellite K.

However, the concern for lightning at the launch pad today has held up ordnance connections. If weather constraint doesn't clear by this afternoon, technicians' amount of clock-time will expire for the day and the operations would slip until Saturday.

For now, liftoff remains planned for Monday morning. But NASA Launch Director Omar Baez says the schedule will be re-evaluated whenever the ordnance work is finished to ensure there is sufficient time to complete pad configuring in daylight hours, such as platform retractions.

Weather forecasters are predicting a 100 percent chance of acceptable conditions for Monday's and Tuesday's launch windows that open daily at 10:02 a.m. local time and extend to 10:50 a.m. local.

The launch time outlook both days calls for a few cirrus clouds at 20,000 feet, unrestricted visibility, easterly winds of 8 to 12 knots and a temperature in the low-to-mid 50 degrees F. An offshore flow will prevent the marine layer from obscuring the view.

Also upcoming today is the pre-launch news conference at 12 noon PST (3 p.m. EST; 2000 GMT). We will have live streaming video of the briefing from launch, spacecraft and weather officials.

Read our full story.

A few lingering technical topics will be discussed for resolution on Friday morning at the Launch Readiness Review, which grants formal permission to enter into countdown operations.

The early weather outlook appears favorable for liftoff Monday at 10:02 a.m. local time (1:02 p.m. EST; 1802 GMT), with forecasters calling for mostly clear skies.

Post-flight analysis of data obtained during the launch will be completed over the next week as managers and engineers travel westward to Vandenberg Air Force Base.

The Landsat spacecraft is mounted atop its two-stage booster and ready to be buttoned up and the rocket's nose cone closed out for launch.

The Flight Readiness Review is planned for next Wednesday, a rehearsal of countdown proceeds follows on Thursday and the Launch Readiness Review occur Friday to give final approval to enter into the countdown.

Read our full story.

The two halves of the aluminum fairing were pushed together to shroud the satellite at the Astrotech processing facility at Vandenberg Air Force Base. The payload was placed aboard the transporter today.

Being used for this mission is the "extended payload fairing" version in the tailored Atlas options, standing 14 feet in diameter and 42 feet fall.

The fairing protects the delicate spacecraft during the initial phases of launch, then gets jettisoned four-and-a-half minutes into flight after the first stage drops away and the Centaur upper stage lights.

The cocooned cargo will be driven to Space Launch Complex 3-East tomorrow for hoisted into the mobile service gantry for attachment to the two-stage Atlas 5 rocket.

Preparations remain on schedule for liftoff Feb. 11.

Fueling of the Landsat spacecraft with its maneuvering propellant has been accomplished. Final touches to button up the satellite are underway in preparation for encapsulation planned for next Wednesday, as the two halves of the Atlas rocket's nose cone are installed.

By the end of next week, the observatory will be at Space Launch Complex 3 for mating atop the booster.

The Landsat Data Continuity Mission spacecraft, LDCM for short, arrived at the base just before Christmas and was unboxed at the Astrotech processing facility.

The satellite's Comprehensive Performance Test of its instruments and systems has been accomplished, a first-motion check of the power-generating solar array was complete and the X-band communications antenna has been installed.

The spacecraft battery is being charged today, and fueling of the spacecraft is scheduled to occur next week.

A convoy escorting the Landsat Data Continuity Mission satellite, or LDCM, traveled from the craft's factory in Gilbert, Arizona, to the launch base in California.

Technicians will spend the next several weeks performing final preps on the LDCM before it is transferred to the launch pad and mounted atop the Atlas 5 rocket that will carry the environmental satellite into orbit Feb. 11.

Read our full story.

The United Launch Alliance booster is scheduled for blastoff in February carrying a remote sensing spacecraft known as the Landsat Data Continuity Mission, or LDCM.

Read our full story.