One day after its release from the International Space Station, the first operational Orbital Sciences Corp. Cygnus resupply craft re-entered the atmosphere Wednesday and burned up over the South Pacific Ocean.

The unmanned cargo vehicle delivered 2,780 pounds of supplies and experiments to the space station in January. Its final mission was to act as a disposal vessel for the outpost's garbage and excess equipment which accumulated aboard the space station.

The astronauts stowed approximately 3,250 pounds of trash for disposal inside the Cygnus spacecraft's pressurized logistics module.

"We are very proud to have a second flawless cargo mission to the space station brought to a successful conclusion this afternoon," said David Thompson, Orbital's chairman and CEO. "Following Cygnus' successful demonstration mission in late 2013 conducted under our COTS research and development partnership with NASA, the picture-perfect execution of the first operational mission is a great way to start the CRS contract. We are looking forward to the next Antares launch and Cygnus cargo delivery mission currently scheduled for early May."

Named for the late astronaut C. Gordon Fullerton, the successful Cygnus flight is the first of eight commercial resupply missions planned by Orbital through 2016. NASA and Orbital signed a $1.9 billion contract for the flights in December 2008.

The spacecraft was attached to the space station for 37 days before departing Tuesday. The space station's robotic arm, under the control of NASA astronaut Mike Hopkins, released the Cygnus at 1141 GMT (6:41 a.m. EST) and the freighter pulsed its rocket thrusters several times to leave the vicinity of the orbiting research laboratory.

A pair of engine burns Wednesday lowered the craft's orbit before it fell into the atmosphere east of New Zealand at about 1820 GMT (1:20 p.m. EST). The re-entry targeted a desolate stretch of the Pacific Ocean clear of busy air and maritime traffic lanes.

The next Cygnus mission is slated to haul about 3,630 pounds of supplies to the space station. Launch aboard an Antares rocket from Virginia's Eastern Shore is scheduled for early May.

A commercial Cygnus cargo-carrying spacecraft departed the International Space Station on Tuesday, heading for a fiery finale over the Pacific Ocean to help clear the outpost of trash at the conclusion of the first operational resupply run by Orbital Sciences Corp.

Read our full story.

NASA confirms Cygnus is now outside the 200-meter keep-out zone around the space station.

Pulses of the Cygnus spacecraft's reaction control thrusters have put the spacecraft on a rapid exit from the space station's vicinity.

The crew has sent the "abort" command as planned to send Cygnus safely away from the space station.

RELEASE. The Cygnus spacecraft is free of the robot arm. The release occurred as the vehicles flew over the South Atlantic Ocean east of Argentina.

Mission control reports the crew is beginning to open the robot arm's snares holding on to the Cygnus grapple fixture.

The crew is ready to command release of the Cygnus spacecraft.

Mission control in Houston reports it is "go" for departure of the Cygnus spacecraft.

Astronauts will loosen the robot arm's grasp on the craft's grapple fixture and back the arm about 1.5 meters, or about 5 feet, away from the vehicle. The space station crew will send an "abort" command to Cygnus using a control panel inside the cupola module to initiate a series of rocket burns to take the automated spaceship away from the space station.

The actual release time is scheduled specifically to coincide with favorable lighting conditions in orbit.

The Cygnus spacecraft is now in the release position about 30 feet from the space station.

As the robot arm puts the Cygnus spacecraft in the proper position for release, Orbital Sciences controllers are checking out the ship's navigation equipment.

After opening bolts and latches holding the Cygnus spacecraft to the space station, the outpost's Canadian-built robot arm is now pulling the commercial cargo ship away from the Harmony module.

Four latches and 16 bolts held the vehicles together on the nadir, or Earth-facing common berthing mechanism on the space station's Harmony module.

Over the next 90 minutes, the Orbital Sciences ground team in Dulles, Va., will activate essential systems on-board the Cygnus spacecraft to prepare the vehicle for its automated departure from the space station.

In the meantime, the robot arm will maneuver Cygnus to a release point about 30 feet below the space station.

Orbital Sciences' commercial Cygnus cargo carrier is due to depart the International Space Station on Tuesday after a 37-day stay at the complex, beginning the final phase of the mission to remove several tons of trash from the outpost.

The space station's robotic arm will remove the Cygnus logistics spacecraft from a berthing port on the Harmony module early Tuesday. Under the control of astronauts Mike Hopkins and Koichi Wakata, the arm will release Cygnus at approximately 1140 GMT (6:40 a.m. EST) and the spacecraft will begin a series of thruster firings to depart the vicinity of the space station.

The Cygnus spacecraft will head for re-entry over the Pacific Ocean on Wednesday. The automated spaceship is designed to burn up in the atmosphere and destroy its payload garbage over a remote plot of sea free of ships and airplanes.

The mission is the first of eight resupply flights by Orbital Sciences Corp. under a $1.9 billion contract with NASA. Cygnus arrived at the space station Jan. 12 after launching aboard an Antares rocket from Wallops Island, Va., on Jan. 9.

A commercial Cygnus spaceship finished a three-day pursuit of the International Space Station on Sunday, delivering nearly 2,800 pounds of supplies, fresh fruit, experiments and gifts to reinforce the orbiting laboratory's stockpiles.

Read our full story.

David Thompson, Orbital's president and CEO, provided this quote in a written statement:

"Our first mission under the CRS contract with NASA was flawlessly executed by our Antares and Cygnus operations team, from the picture-perfect launch from NASA's Wallops Flight Facility to the rendezvous, capture and berthing at the space station this morning," Thompson said. "From the men and women involved in the design, integration and test, to those who launched the Antares and operated the Cygnus, our whole team has performed at a very high level for our NASA customer and I am very proud of their extraordinary efforts."

First-stage and second-stage capture are complete, and 16 bolts will soon drive to firmly attach Cygnus to the space station.

The official time of capture of Cygnus with the Harmony module's common berthing mechanism was 8:05 a.m. EST (1305 GMT) as the space station flew 260 miles high southeast of Australia and Tasmania.

The space station crew plans to open hatches between Harmony and Cygnus later today or on Monday to begin transferring 2,780 pounds of cargo into the complex.

Frank DeMauro, Cygnus program manager at Orbital Sciences, says the spacecraft performed flawless throughout its three-day flight to the International Space Station. "We are just ecstatic to be at this point," he says.

The robot arm has positioned Cygnus in the so-called ready-to-latch position at the Harmony module's Earth-facing berthing port. Four latches will close to create an initial connection.

The astronauts report Cygnus is now at the so-called "pre-install" position aligned with the berthing port on Harmony.

While the robot arm maneuvers Cygnus toward its berthing port on the Harmony module, the Orbital Sciences team here in Dulles is deactivating systems on the cargo craft for its multi-week stay at the complex.

The Cygnus spacecraft can receive power from the space station through the robot arm, so the solar panels no longer have to point toward the sun to charge the ship's batteries. And the control team is switching off the LIDAR laser ranging sensors since they are no longer needed.

Cygnus is scheduled to stay more than 40 days at the space station. Departure is set for Feb. 18, but that could change.

Over the coming hour, the astronauts will guide the robot arm to move the Cygnus spacecraft through a choreographed set of maneuvers to line up the pressurized compartment's hatch with the Earth-facing port on the Harmony module.

Once in position there, a series of latches and 16 bolts will drive closed to create a sturdy connection between Harmony and Cygnus.

The Cygnus is carrying about 2,780 pounds of supplies. If you count the mass of the bags and packing material, the craft's total cargo haul is 3,231 pounds.

Live NASA TV coverage is about to resume with the installation and berthing of the Cygnus cargo craft to the nadir, or Earth-facing, port on the space station's Harmony module.

Capture confirmed! The Cygnus spacecraft is now in the grasp of the International Space Station's robotic arm after a manual grapple under the control of astronaut Mike Hopkins.

Hopkins grappled Cygnus while the space station flew over the Indian Ocean northeast of Madagascar.

The robotic arm is in motion to capture Cygnus.

NASA says the capture of Cygnus will occur when the space station is out video communications range with the ground.

Astronauts Mike Hopkins and Koichi Wakata are working inside the cupola module. Hopkins will manually take control of the 58-foot robotic arm to grapple the Cygnus spacecraft in a few minutes.

The space station is ready for capture of Cygnus. The spacecraft has arrived at a point less than 40 feet from the space station.

Mission control in Houston reports Cygnus is now initiating the last phase of its approach, heading to a final hold point about 10 meters, or 32 feet, directly below the space station.

No problems have been reported with the rendezvous this morning.

Cygnus is now at the hold point about 30 meters, or 98 feet, below the space station.

Range is now 60 meters, or about 196 feet.

The International Space Station and Cygnus just sailed over the Orbital Sciences Cygnus control center in Virginia. Company managers stepped outside to take a look as the massive laboratory flew overhead.

Range is now 200 meters, or about 656 feet.

Cygnus is moving again! The spacecraft, fitted with a pressurized cargo compartment built by Thales Alenia Space in Italy, is moving toward a hold point 30 meters, or 98 feet, from the space station.

Space station mission control in Houston is "go" to continue the approach of the Cygnus spacecraft.

The spacecraft continues to hold less than 1,000 feet below the space station. This pause allows mission controllers to evaluate the status of all key systems on both vehicles before clearing Cygnus to approach inside the "keep out sphere," an imaginary bubble stretching 200 meters, or 656 feet, from the complex on all sides.

Cygnus is now holding approximately 250 meters, or 820 feet, below the space station.

Astronaut Mike Hopkins is designated the primary robot arm operator for this morning's capture. He will control the 58-foot arm from a work station inside the windowed cupola module.

Japanese astronaut Koichi Wakata is in charge of monitoring the approach of Cygnus. He will be able to send abort or hold commands to Cygnus in the case of any problems.

Cygnus is now about 290 meters, or 951 feet, directly below the International Space Station. The spacecraft's LIDAR laser ranging system continues tracking reflectors on the outpost's Japanese lab module.

The spacecraft will hold at 250 meters, or about 820 feet, below the space station to give officials time to evaluate the health of both the space station and Cygnus before giving the "go" for final approach.

The Cygnus spacecraft is less than a kilometer, or about 3,000 feet, from the International Space Station at this time. The last major course correction burn, known as ADV3, has been completed to put Cygnus on track to arrive directly below the space station in a few minutes.

Orbital Sciences reports the LIDAR laser ranging system is activated and has acquired reflectors mounted on the nadir, or Earth-facing, side of the Japanese Kibo laboratory. In a few minutes, Cygnus will switch from GPS to LIDAR navigation.

We're reporting live from the Orbital Sciences mission control center in Dulles, Va. Everything is on track with the rendezvous of the Cygnus spacecraft with the International Space Station.

Coming up in a few minutes at about 4:27 a.m. EST (0927 GMT), the Cygnus spacecraft will fire its thrusters for one of the last major approach maneuvers to put the ship on course to arrive on the R-bar, the imaginary line connecting the space station with Earth.

The space station crew reports they can already see the Cygnus spacecraft, which is now less than 2 miles from the complex.

Grapple of Cygnus with the space station's robot arm is now expected at 6:13 a.m. EST (1113 GMT). The slight change in capture time was due to less-than-expected drag on the space station because of an uptick in solar activity.

After a smooth first two days in orbit, the Orbital Sciences Corp. Cygnus cargo-carrying spacecraft is in the final leg of its pursuit of the International Space Station.

The automated spaceship will close in on the huge 450-ton complex early Sunday, with grapple by the space station's robotic arm scheduled for 6:02 a.m. EST (1102 GMT).

The privately-operated spacecraft is packed with more than 3,200 pounds of equipment, food, spacewalking gear, and experiments, including scientific hardware for 23 experiments involving 8,675 elementary, junior high and high school students in the United States and Canada.

The spacecraft's pressurized cabin also contains experiments for 600 scientists, according to Tara Ruttley, NASA's space station program scientist. That represents the largest complement of scientific experiments delivered to the space station by any mission to date under the program's U.S. national laboratory designation.

As of approximately 7 p.m. EST Saturday, the Cygnus was about 200 kilometers behind the space station. That distance was expected to close to about 6 kilometers, or less than 4 miles, shortly after 3:30 a.m. EST (0830 GMT) Sunday.

The Cygnus will first rely on comparing GPS navigation data from its on-board computer and the space station. The two spacecraft will establish a radio link early Sunday through a proximity communications system provided by the Japanese space agency.

After arriving at a hold point about 820 feet directly below the space station around 4:50 a.m. EST (0950 GMT), Cygnus will switch to a LIDAR sensor, which fires light pulses at reflectors mounted on the space station to measure the range and closing rate between the two vehicles.

The laser-guided navigation system will feed data into the Cygnus guidance computer, telling the spacecraft when and where to fire its rocket jets to maneuver the unmanned freighter to a point 30 feet below the space station.

Once Cygnus arrives at a hold point just below the complex, astronaut Mike Hopkins will take control of the lab's robot arm to reach out and grapple the free-floating 16.8-foot-long spacecraft at about 6:02 a.m. EST (1102 GMT).

The robot arm will maneuver the Cygnus spacecraft onto the Harmony module's Earth-facing berthing port about an hour later.

Delayed one day by cold weather and another day by concern about space radiation, an Orbital Sciences Corp. Antares rocket carrying a commercially developed cargo ship blasted off Thursday and climbed into orbit, kicking off the company's first operational flight to deliver supplies and equipment to the International Space Station.

Read our full story.

Both Cygnus solar arrays have been extended.

One of the Cygnus spacecraft's solar panels has been deployed, NASA says.

Deployment of the Cygnus solar arrays, manufactured by Dutch Space, should begin shortly.

Cygnus separation confirmed!

Engineers report the rocket is very close to its targeted trajectory.

Antares is in orbit! The Castor 30B upper stage motor shut down on time and has reached orbit. Deployment of the Cygnus cargo craft occurs at T+plus 9 minutes, 54 seconds.

T+plus 7 minutes, 25 seconds. About 30 seconds remaining in the second stage burn.

T+plus 7 minutes. Motor pressure and attitude are nominal. Altitude is 205 kilometers.

T+plus 6 minutes. Systems are reported to be in good shape as the enhanced Castor 30B fires with 90,000 pounds of thrust.

T+plus 5 minutes, 50 seconds. Orbital Sciences reports a good separation of the payload fairing and ignition of the Antares second stage Castor 30B motor built by ATK for a 128-second burn to inject the rocket into orbit.

T+plus 4 minutes, 50 seconds. "Excellent stage one performance" being reported by launch control. The first stage hit its velocity target with an error of just 40 feet per second.

T+plus 4 minutes. First stage cutoff confirmed, and the Ukrainian-built stage has separated from the Antares second stage.

The flight is now entering a coast phase lasting approximately 103 seconds, in which the rocket will ascend to an altitude of 179 kilometers, or 111 miles. In the last few seconds of the ballistic coast, the Antares rocket will jettison its 12.8-foot-diameter payload fairing and an interstage adaptor around the second stage motor.

T+plus 3 minutes, 45 seconds. Altitude 300,000 feet, Pressure and steering are nominal.

T+plus 3 minutes. Altitude is 100,000 feet. The rocket's guidance system continues flying the rocket on course, and all systems are reported to be in good shape. The two AJ26 first stage engines will shut down at T+plus 3 minutes, 54 seconds, followed a few seconds later be separation of the liquid-fueled first stage.

The first stage engines will throttle down at T+plus 3 minutes, 24 seconds, at an altitude of 49 miles.

T+plus 2 minutes, 15 seconds. Altitude about 100,000 feet.

T+plus 2 minutes. The first stage's twin AJ26 main engines are powering the rocket into the upper atmosphere with about 750,000 pounds of thrust.

T+plus 90 seconds. Power is nominal, engines are nominal.

T+plus 60 seconds. The rocket is flying steady and accelerating near the speed of sound, sending a thunderous roar across the Eastern Shore.

T+plus 30 seconds. The 13-story Antares booster is rising into the sky from Wallops Island and beginning to pitch on a southeast trajectory - at an initial azimuth of 110.2 degrees - over the Atlantic Ocean.

LIFTOFF of the Antares rocket with the "C. Gordon Fullerton" Cygnus cargo craft on a resupply mission to the International Space Station.

T-minus 5 seconds. Transporter erector is swinging back. Standing by for ignition!

T-minus 15 seconds. The engine steering check is underway.

T-minus 30 seconds and counting to third flight of Antares.

T-minus 45 seconds.

T-minus 60 seconds. High speed video cameras are activating.

T-minus 90 seconds.

T-minus 2 minutes. Flight computer is ready. The rocket's propellant tanks are pressurizing now.

In the next few moments, the Antares first stage's propellant tanks will pressurize for flight, and computers will monitor the rocket and ground system paramters to ensure everything is ready for liftoff.

At T-minus 15 seconds, the two AJ26 first stage engines will swivel at the base of the rocket to ensure they can steer the launch vehicle in flight.

At T-minus 5 seconds, the transporter-erector-launcher will retract away from the rocket, leading to ignition of the AJ26 engines as clocks hit zero.

Liftoff will occur 2 seconds later after computers verify the engines are running normally.

T-minus 3 minutes, 30 seconds. The auto sequence has started.

T-minus 4 minutes and counting. The automatic countdown sequence begins in a few seconds.

T-minus 5 minutes and counting. The rocket is now running on its own battery.

T-minus 6 minutes and counting. The Antares rocket's avionics will be switched from external power to an on-board battery in about one minute.

T-minus 7 minutes and counting. The liquid oxygen tank is full. The transporter erector is armed for rapid retract in the final seconds of the countdowm.

T-minus 8 minute and counting. No problems are reported in the countdown and the weather continues to look favorable for liftoff at 1:07:05 p.m. EST.

At the time of launch, the International Space Station will by flying over the Atlantic Ocean off the east coast of Brazil at an altitude of 261 statute miles.

T-minus 10 minutes and counting. The next step in the engine chilldown procedure is now beginning. And final vehicle arming is underway.

T-minus 11 minutes and counting. The final prelaunch poll of the Antares team confirms all positions are ready for the final phase of the countdown.

T-minus 13 minutes and counting. In the final 10 minutes of the countdown, the Antares rocket's avionics systems will be transitioned to internal power at T-minus 5 minutes.

At T-minus 3 minutes, 30 seconds, the automatic countdown sequence will begin. The first stage's propellant tanks will begin pressurizing at T-minus 2 minutes.

T-minus 14 minutes and counting. The roughly five-ton Cygnus spacecraft, christened the "C. Gordon Fullerton" after the late former astronaut and test pilot, is running on internal power and is in good shape for launch.

T-minus 16 minutes and counting. Another poll is coming up at T-minus 12 minutes to approve the start of a medium-flow chilldown, another step to condition the main engines for ignition.

The Antares launch team continues stepping through countdown procedures toward liftoff at 1:07:05 p.m. EST (1807:05 GMT).

The Range is NO GO for launch at this time due to a group of duck hunters inside the danger area around the Antares launch site. And the distance focused overpressure rule remains RED.

Today's launch will fly southeast from Wallops Island, Va. Communications sites in Virginia, North Carolina and Bermuda will track the rocket during its 10-minute flight, along with support from NASA's Tracking and Data Relay Satellite System.

Check out a timeline of key events during the launch.

Loading of more than 20,000 gallons of RP-1 kerosene fuel into the Antares Ukrainian-built first stage is complete. Liquid oxygen continues flowing into the rocket until the final few minutes.

Engineers will soon do final checks of the rocket's flight termination system and configuring that device for launch.

The launch team is waiting on data from another weather balloon to see if they can clear the distance focused overpressure rule. Nearby homes have already been evacuated, but the rule is still RED.

The Wallops range is still RED due to the distance focused overpressure rule. There is a way around this issue by evacuating nearby homes inside the Antares rocket's blast danger area.

T-minus 30 minutes and counting. Loading of kerosene into the rocket is going well. The first stage's helium pressurant bottles are now submerged.

Chilldown is underway and all systems are reported to be in good shape for an on-time launch at 1:07 p.m. EST.

T-minus 35 minutes and counting. The team is "go" for low-flow chilldown of the main engines beginning in about five minutes, pending resolution of the distance focused overpressure issue.

T-minus 40 minutes and counting. The launch team will polled in a few minutes to begin low-flow chilldown of the first stage's AJ26 engines. The chilldown procedure ensures the propellant lines leading to the engines are conditioned for the shock of super-cold liquid oxygen stored at minus 298 degrees Fahrenheit.

The launch team has verified good telemetry links between the rocket and ground controllers.

T-minus 45 minutes and counting. The launch team is loading the flight trajectory file into the Antares flight computer.

Liquid oxygen is flowing into the Antares rocket's Ukrainian-built first stage at a rate of 150 gallons per minute.

The Cygnus spacecraft on this flight is carrying 1,465.69 kilograms, or 3,231 pounds, of supplies to the International Space Station, including the mass of the storage bags. It measures about 16.8 feet tall, and the pressurized cargo module has a volume of about 18 cubic meters, or 635 cubic feet.

Here are some statistics on today's launch:

• 3rd Antares rocket launch
• 9th orbital launch from the Mid-Atlantic Regional Spaceport
• 2nd launch of a Cygnus spacecraft
• 1st space launch from Wallops in 2014
• 2nd U.S. space launch in 2014
• 3rd global space launch in 2014

The transporter-erector-launcher system, essentially a mobile launch tower next to the rocket, is configured to pull back from the launch vehicle, the launch team reports. Gripper arms on the tower have opened from around the rocket.

The tower will retract a few degrees away from the rocket in the final seconds of the countdown.

T-minus 60 minutes and counting.

After chilldown begins at T-minus 30 minutes, the window will be limited to 10 minutes. After passing the T-minus 10 minute point, the launch window is again shortened to just 5 minutes.

Today's launch is carrying Orbital's second Cygnus spacecraft to orbit on its first operational mission.

The unmanned cargo hauler is comprised of two modules - a service and propulsion module built by Orbital Sciences and a pressurized logistics module built by Thales Alenia Space in Italy. It measures nearly 17 feet long and 10 feet in diameter.

The spacecraft features 32 thrusters built by Aerojet Rocketdyne and solar panels provided by Dutch Space, a subsidiary of EADS Astrium based in the Netherlands.

Cygnus will extend its solar panels moments after deploying from the Antares second stage about 10 minutes after liftoff. Engineers expect to get a signal from the spacecraft a few minutes after separation confirming that the panels have deployed.

Fueling operations continue for today's liftoff at 1:07:06 p.m. EST (1807:06 GMT).

Wallops regularly launches suborbital sounding rockets for scientific and engineering research purposes, and the facility has occasionally launched small satellites with Orbital Sciences Minotaur rockets.

The Virginia Commercial Space Flight Authority owns the Mid-Atlantic Regional Spaceport, which oversaw development of the launch pad used by Antares. The Commonwealth of Virginia paid for about $80 million of the $120 million cost of the launch pad, with most of the rest of the funding coming from the federal government.

Combined with the cost of the Antares hangar and a Minotaur rocket launch pad just south of the Antares facility, the MARS complex cost about $150 million.

RP-1 kerosene fuel is now being loaded into the Antares rocket's Ukrainian-built first stage. Liquid oxygen loading is also underway.

All ground crews have evacuated the launch pad to a safe distance.

The live video and audio stream of the countdown provided by NASA's Wallops Flight Facility has gone down.

The countdown has resumed and propellant will soon be being pumped into the Antares rocket's first stage. About 21,000 gallons of RP-1, a high-refined rocket-grade kerosene, and about 41,000 pounds of liquid oxygen will be loaded into the first stage over the next half-hour.

The kerosene is stored at roughly room temperature and the liquid oxygen is chilled to minus 383 degrees Fahrenheit. The oxygen will slowly boil off during the countdown, and liquid oxygen continue flowing into the rocket until shortly before liftoff.

The first stage tanks are designed by Yuzhnoye and built by Yuzhmash in Ukraine based on heritage from the Zenit rocket. The liquid oxygen tank is positioned in the upper part of the 12.8-foot-diameter stage and the RP-1 tank is in the lower part of the stage.

The first stage's two AJ26 engines will consume the liquid propellant during a 3-minute, 54-second burn.

The Antares second stage, a Castor 30B motor built by ATK, is propelled by solid fuel already loaded into the rocket.

The latest weather briefing shows just a 5 percent chance of violating weather constraints for the 1:07 p.m. EST launch time. The outlook calls for a few clouds at 12,000 feet and 25,000 feet, unrestricted visibility, east winds at 12 to 16 knots, a temperature of 42 degrees Fahrenheit and a humidity of 58 percent.

The countdown has entered its second built-in hold for 12 minutes. The hold was shortened from the standard time of 15 minutes to make up for an unplanned hold earlier in the countdown. This hold allows the launch team to finish up open work before giving the "go" for fueling, which is supposed to begin at 11:37 a.m. EST (1637 GMT).

The Wallops Range is red due to the distance focused overpressure rule. The distance focused overpressure rule addresses concerns that the blast of launch could damage nearby structures.

There are backup procedures in place to evacuate nearby public buildings to remove the threat of a blast damaging a building with occupants.

Here's the launch timeline the Antares rocket will follow during launch.

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The red team took a look at the small liquid oxygen leak on a ground maintenance line and found it was not dripping onto any important launch pad systems. The issue has been cleared and launch remains on schedule for 1:07 p.m. EST (1807 GMT).

The countdown was paused for about 3 minutes a few minutes ago as the launch team worked to resolve the issue. The time will be made up in a build-in hold in a few minutes.

A red team is being prepared to enter the launch pad to investigate the liquid oxygen leak. The launch team has paused pressurization of the gaseous nitrogen system, and officials are donning proper safety gear to enter the pad.

Engineers are dispatching a red team to take a look at a liquid oxygen leak at the launch pad.

Chilldown of the liquid oxygen loading system is continuing as engineers finish testing of the rocket's ordnance systems. No problems are being reported in the countdown at this point.

The launch team has completed testing of the rocket's flight termination system, and the countdown is now moving into activating the vehicle's pyrotechnic ordnance systems in a few minutes.

Chilldown of the liquid oxygen loading system is underway. This procedure conditions the launch facility's pipes for the flow of liquid oxygen, which is chilled to minus 298 degrees Fahrenheit.

Coming in a few minutes will be testing of the rocket's telemetry links and flight termination system, which would be used to destroy the launcher if it flew off course.

The launch team is powering up telemetry transmitters at this point in the countdown ahead of testing of the rocket's communications and flight termination systems.

Officials report no issues are being worked in the countdown at this point.

The Antares rocket was powered up early this morning and the launch team is going through a checklist of testing to ensure all systems are in good shape. The launch pad is also evacuated of all personnel at this time.

In the next hour, the launch team will begin the process of priming the plumbing on the launch facility for loading of super-cold liquid oxygen, which begins at about 11:37 a.m. EST (1637 GMT).

The countdown is progressing smoothly this morning after getting underway before sunrise. The launch team has powered up the Antares rocket for prelaunch testing ahead of liftoff at 1:07:06 p.m. EST (1807:06 GMT).

The mission will be the third launch of the Orbital Sciences Antares rocket after a successful test launch in April 2013 proved the two-stage rocket could deliver payloads into low Earth orbit, followed by the Sept. 18 launch of an Antares with the first Cygnus cargo spacecraft.

The forecast has improved with an 85 percent chance of acceptable weather at the time of launch. The temperature is expected to be about 42 degrees Fahrenheit, with light winds from the east-southwest and mostly sunny skies.

Here is an excerpt from a statement released by Orbital Sciences:

"Following a comprehensive review of data related to the radiation environment in space, further reviews and modeling of the rocket's avionics systems, and the forecast for favorable terrestrial weather conditions at the Wallops Island launch facility, the Antares launch team has decided to proceed forward with a launch attempt of the Orbital-1 CRS mission to the International Space Station tomorrow, January 9.

"Upon a deeper examination of the current space weather environment, Orbital's engineering team, in consultation with NASA, has determined that the risk to launch success is within acceptable limits established at the outset of the Antares program."

Here is an excerpt from a statement released by Orbital Sciences:

"Following a comprehensive review of data related to the radiation environment in space, further reviews and modeling of the rocket's avionics systems, and the forecast for favorable terrestrial weather conditions at the Wallops Island launch facility, the Antares launch team has decided to proceed forward with a launch attempt of the Orbital-1 CRS mission to the International Space Station tomorrow, January 9.

"Upon a deeper examination of the current space weather environment, Orbital's engineering team, in consultation with NASA, has determined that the risk to launch success is within acceptable limits established at the outset of the Antares program."

Orbital Sciences has decided to press on with a launch attempt tomorrow at 1:07:06 p.m. EST (1807:06 GMT) after a one-day delay because of elevated solar radiation.

The Antares launch team will get to work early Thursday inside the launch control center at Wallops Flight Facility in Virginia with the start of the countdown.

The call-to-stations for the engineers on the launch team is scheduled for 4:52 a.m. EST (0952 GMT), with voice checks and opening of the prelaunch checklist scheduled for 5:22 a.m. EST (1022 GMT).

Workers will clear the launch pad at about 6:27 a.m. EST (1127 GMT), followed by vehicle power-up at 7:02 a.m. EST (1202 GMT).

Chilldown of the Antares liquid oxygen loading system begins at 9:52 a.m. EST (1452 GMT) in preparation for propellant loading at 11:37 a.m. EST (1637 GMT).

Follow activities with this countdown timeline.

Orbital Sciences officials plan to decide around 5 p.m. EST whether to try another launch attempt Thursday. Engineers are studying radiation levels from a series of solar flares this week.

The radiation could corrupt memory on the Antares rocket's second stage during launch, officials said.

The weather forecast for Thursday looks favorable with a 75 percent chance of acceptable conditions. The primary concern is with thick clouds at the Wallops Flight Facility.

Weather is expected to deteriorate Friday into the weekend. Friday's outlook calls for just a 30 percent chance of good weather due to low and thick clouds.

DELAY. The launch of the first Orbital Sciences resupply flight to the International Space Station has been delayed at least one day due to elevated solar radiation following strong solar flares Tuesday.

"Early this morning the Antares launch team decided to scrub today's launch attempt due to an unusually high level of space radiation that exceeded by a considerable margin the constraints imposed on the mission to ensure the rocket's electronic systems are not impacted by a harsh radiation environment," Orbital Sciences said in a statement. "The solar flux activity that occurred late yesterday afternoon has had the result of increasing the level of radiation beyond what the Antares engineering team was monitoring earlier in the day.

"Overnight, Orbital engineers who are experts in the field ran numerous models to ensure that all possibilities to preserve the launch were examined. However, due to significantly elevated flux levels, the Antares team decided to postpone the launch to spend the day further examining the potential effects of the space radiation on the rocket's avionics suite," the statement said.

Orbital Sciences said it would consult with NASA and outside experts today to track radiation levels in hopes of setting a launch date as soon as possible.

If possible, liftoff on Thursday would occur at 1:10 p.m. EST (1810 GMT). Arrival at the space station would still occur Sunday morning.

The Antares launch team will get to work early Wednesday inside the launch control center at Wallops Flight Facility in Virginia with the start of the countdown toward liftoff at 1:32:35 p.m. EST (1832:35 GMT).

The call-to-stations for the engineers on the launch team is scheduled for 5:17 a.m. EST (1017 GMT), with voice checks and opening of the prelaunch checklist scheduled for 5:47 a.m. EST (1047 GMT).

Workers will clear the launch pad at about 6:52 a.m. EST (1152 GMT), followed by vehicle power-up at 7:27 a.m. EST (1227 GMT).

Chilldown of the Antares liquid oxygen loading system begins at 10:17 a.m. EST (1517 GMT) in preparation for propellant loading at 12:02 p.m. EST (1702 GMT).

Follow activities with this countdown timeline.

Orbital Sciences Corp. plans to launch the first of eight commercial logistics deliveries to the International Space Station on Wednesday under a $1.9 billion NASA contract to outsource cargo transportation services to the private sector.

Read our full story.

Orbital Sciences and NASA officials today cleared the Antares rocket for launch Wednesday at 1:32 p.m. EST with a Cygnus resupply craft headed for the International Space Station, pending the conclusion of final countdown preparations overnight.

The launch readiness review this morning concluded the Antares rocket, the Cygnus cargo payload and ground systems at the Wallops Flight Facility in Virginia were all go for launch.

"We've got a little big of margin left in the schedule but not a lot, and we intend to to conitnue to work through the night," said Frank Culbertson, executive vice president and general manager of Orbital's advanced programs group.

The 133-foot-tall Antares rocket rolled to launch pad 0A on Sunday, and technicians rotated the launcher vertical late Sunday night. The rollout was a day later than planned to give workers time to troubleshoot a hydraulics issue on the Antares rocket's erector.

"The team has been out there 24 hours around the clock getting the rocket connected to the pad," said Mike Pinkston, Orbital's Antares rocket program manager.

Since rollout, workers have connected the rocket to the launch facility's fluid and electrical systems. On Monday night, engineers completed checkout of the first stage's engine steering system, according to Pinkston.

Today, ground crews are completing combined systems testing involving the Antares rocket, Cygnus spacecraft and ground systems. And final vehicle closeouts are in work, Pinkston said.

"Pending the successful completion of our clouseot activities, we'll be ready for launch tomorrow," Pinkston said.

Liftoff is scheduled for 1:32:35 p.m. EST (1832:35 GMT). The launch window extends about 5 minutes and is timed for the moment the space station's flight path passes over Wallops.

The weather forecast calls for very cold conditions, with launch time temperatures expected to be between 30 and 34 degrees Fahrenheit. The outlook calls for broken high-level clouds, light winds out of the southwest, and good visibility.

There is just a 5 percent chance weather will violate restrictions for the Antares launch, with the only concern being a slight chance of thick clouds.

For the second time in three weeks, Orbital Sciences transferred an Antares rocket to its Virginia launch pad Sunday for launch this week on a resupply flight to the International Space Station.

The one-mile trip from the Antares assembly hangar occurred Sunday afternoon. An issue with a hydraulics system on the rocket's mobile transporter delayed the rollout from Saturday night.

Check out photos of the rollout.

Orbital Sciences has pushed back next week's launch of a commercial resupply mission to the International Space Station by at least one day to Wednesday to dodge frigid temperatures expected on Virginia's Eastern Shore.

Read our full story.

DELAY. NASA officials have decided to go ahead with a series of spacewalks beginning this weekend to restore the International Space Station's cooling system to full functionality, delaying the launch of a commercial resupply mission to January.

One of two ammonia coolant loops on the space station's external thermal control system went offline last week due to a balky flow control valve inside a pump module mounted on the right side of the outpost's truss.

While NASA engineers studied the problem and tried to come up with a temporary fix, Orbital Sciences Corp. pressed on with preparations to launch an Antares rocket and Cygnus cargo freighter this week from Virginia.

Technicians moved the 13-story rocket to the launch pad this morning in a bid to preserve a launch opportunity as early as Thursday night.

The rocket will be rolled back to its horizontal integration facility for storage until January.

The flight is the first of eight resupply missions to be conducted by Orbital Sciences under a $1.9 billion contract with NASA.

The first spacewalk to replace the pump module containing the suspect flow control valve is set for Saturday by Rick Mastracchio and Michael Hopkins. Two more spacewalks are scheduled for Dec. 23 and Dec. 25.

The initial forecast for Thursday's launch opportunity indicates chilly weather on Virginia's Eastern Shore and only a slight chance of weather being an issue for liftoff at 9:19 p.m. EST (0219 GMT).

There is just a 5 percent chance conditions will violate the Antares rocket's launch weather rules, according to a NASA spokesperson.

The forecast calls for partly to mostly cloudy skies, southwest winds between 10 and 15 knots, and a temperature between 44 and 48 degrees Fahrenheit.

Orbital Sciences and NASA will convene a launch readiness review at 10 a.m. EST Wednesday.

In a bid to preserve an opportunity to launch a cargo resupply flight to the International Space Station on Thursday, Orbital Sciences Corp. rolled an Antares rocket to its seaside launch pad in Virginia on Tuesday.

The one-mile trip from the Antares assembly hangar began before dawn. A self-propelled transporter carried the two-stage booster down a two-lane road south from the horizontal integration facility, then up the ramp to launch pad 0A at NASA's Wallops Flight Facility on Virginia's Eastern Shore.

By about 10 a.m. EST (1500 GMT), hydraulic pistons had lifted the 133-foot-tall rocket vertical on top of the pad's launch mount. Technicians planned to make final electrical and fluid connections between the rocket and the launch pad later Tuesday.

Launch is set for 9:19 p.m. EST Thursday (0219 GMT Friday), but NASA is still working to resolve an issue with one of two external coolant loops on the International Space Station.

If launch goes ahead, the commercial Cygnus cargo craft would arrive at the space station early Sunday with 2,780 pounds of supplies.

NASA wants both loops to be functional when the Cygnus gets to the complex.

Ground teams at NASA's Johnson Space Center in Houston are developing a way to regulate the temperature of ammonia inside the Loop A of the space station's coolant system. Engineers say a balky flow control valve inside a pump module malfunctioned last week, causing temperature of ammonia inside the loop to drop.

Managers don't want to introduce the colder-than-normal ammonia into heat exchangers because they fear it would damage the system, so the suspect coolant loop remains offline and most of the space station's electronics, which produce heat that needs to be dissipated, have been transferred over to Loop B.

NASA says it needs both loops available before committing to launch the Cygnus cargo craft.

Meanwhile, astronauts aboard the International Space Station continue preparing for spacewalks beginning as soon as the end of this week to replace the pump module containing the faulty flow control valve.

Working over the weekend to stow cargo inside an unmanned resupply craft, Orbital Sciences Corp. engineers plan to move an Antares rocket to a Virginia launch pad early Tuesday unless NASA managers reviewing a problem with the International Space Station's cooling system call a halt to launch preparations.

Orbital Sciences, the Antares rocket's private developer and operator, continued to ready the launcher and its Cygnus logistics-carrying payload over the weekend as NASA engineers evaluated a valve issue that crippled one of the space station's two external cooling loops last week.

The launch was delayed one day to Thursday night to give NASA more time to study the problem. Launch is currently targeted for 9:19 p.m. EST Thursday (0219 GMT Friday) from NASA's Wallops Flight Facility on Virginia's Eastern Shore.

Kenny Todd, chairman of the space station's Mission Management Team, said this morning that a decision whether to press on with the Antares launch would come today or tomorrow.

The station crew and ground controllers had to power down non-critical systems last week when they noticed the temperature of ammonia coolant in one of the space station's two cooling loops was getting too cold. A flow control valve inside a pump module on the right side of the space station's power truss is believed to be the culprit.

Todd said engineers are looking at using another valve upstream from the flow control valve to regulate the temperature of the ammonia, which has to be at the right temperature to ensure it does not damage heat exchangers used to dissipate heat from the outpost's electronics, computers and other systems.

NASA does not want to proceed with the Antares resupply launch without both coolant loops functioning. A series of spacewalks may be ordered later this week to replace the suspect pump module, which would force a delay of the Antares launch until January.

Read our earlier story for more details.

Technicians installed the Antares rocket's 12.8-foot-diameter nose fairing Monday, marking the end of the launcher's assembly inside a horizontal integration hangar at NASA's Wallops Flight Facility in Virginia.

On Sunday, ground crews loaded more than 200 pounds of time-sensitive cargo into the Cygnus spacecraft's pressurized module, consisting mostly of hardware for science experiments. Workers then purged the module with air and closed the forward hatch before enclosing the 10-foot-diameter spacecraft inside the payload fairing.

The final cargo load also included 33 CubeSats to be delivered to the space station inside the Cygnus resupply freighter for release from the Japanese lab's robot arm later.

If launch preps continue, the rocket will be rolled out of the hangar before dawn Tuesday and down a two-lane road to launch pad 0A, a complex leased from NASA and operated by the Mid-Atlantic Regional Spaceport. The 13-story rocket is mounted on a self-propelled transporter for the one-mile journey.

Later Tuesday morning, hydraulic pistons will lift the rocket vertical on the launch mount.

A launch readiness review is also scheduled Tuesday, giving officials an opportunity to discuss the status of the rocket, the Cygnus cargo spacecraft, ground systems, and the space station.

The cargo delivery flight is the first of eight space station logistics missions contracted to Orbital Sciences by NASA. The mission follows a full-up demonstration flight of the Antares rocket and Cygnus spacecraft to the space station in September and October.