Wrapping up a successful test flight, the first commercial Cygnus resupply freighter fell back into the atmosphere Wednesday, committing a fiery final act disposing 2,850 pounds of garbage from the International Space Station.

The uncrewed spacecraft re-entered the atmosphere over the Pacific Ocean east of New Zealand at about 2:15 p.m. EDT (1815 GMT), according to Orbital Sciences Corp., the prime contractor for Cygnus.

The re-entry ended 35 days in space for the first Cygnus spacecraft, which was named for G. David Low, a former NASA astronaut and Orbital executive who was instrumental in development of the company's cargo transport system.

The re-entry punctuated a successful demonstration for Orbital Sciences, in which the company tested the Cygnus spacecraft and Antares rocket on a complete mission profile mimicking eight operational space station logistics flights the company plans to begin in December.

Orbital conducted the test flight under the banner of NASA's Commercial Orbital Transportation Services program, which fostered a public-private partnership between the space agency and two companies - Orbital Sciences and SpaceX - to develop private cargo transportation systems to replace capability lost with the space shuttle's retirement.

Orbital's Cygnus and SpaceX's Dragon spacecraft are now part of the space station's fleet of cargo vehicles, joining Russia's Progress freighter, Europe's Automated Transfer Vehicle and Japan's H-2 Transfer Vehicle.

The Cygnus demo flight launched on an Antares rocket Sept. 18 from Wallops Island, Va., and the 16.8-foot-long spacecraft arrived at the space station Sept. 29 with more than 1,300 pounds of food, experiments and other supplies.

The space station's astronauts unpacked the cargo and replaced it with bags of unneeded equipment and trash, preparing Cygnus to leave the complex Tuesday.

Since the craft's departure, Cygnus fired its thrusters to fly a safe distance from the space station, then lowered its orbit in two major braking burns Wednesday to plunge back into the atmosphere.

Officials designed most of the spacecraft to burn up during re-entry, but a few fragments of the spaceship were expected to survive the fiery fall into the remote South Pacific Ocean.

"With the COTS development phase now successfully completed, we are now turning our full attention to the eight operational resupply missions covered by our Commercial Resupply Services contract with NASA," said Frank Culbertson, Orbital's executive vice president and general manager for advanced programs. "Each Cygnus is capable of delivering a large quantity of pressurized cargo, totaling up to 20,000 kilograms over the eight missions, including crew supplies, spare parts and equipment, and scientific experiments for the ISS. We are looking forward to starting these missions in December."

The Orbital Sciences Cygnus cargo ship completed its first visit to the International Space Station on Tuesday, departing the complex after a highly successful test flight as workers load the second Cygnus spacecraft with supplies for another mission in December.

Read our full story.

1136 GMT (7:36 a.m. EDT)
NASA confirms Cygnus is now outside the 200-meter keep-out zone around the space station.
1134 GMT (7:34 a.m. EDT)
Pulses of the Cygnus spacecraft's reaction control thrusters have put the spacecraft on a rapid exit from the space station's vicinity.
1132 GMT (7:32 a.m. EDT)
The crew has sent the "abort" command as planned to send Cygnus safely away from the space station.
1131 GMT (7:31 a.m. EDT)
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.
1130 GMT (7:30 a.m. EDT)
Mission control reports the crew is beginning to open the robot arm's snares holding on to the Cygnus grapple fixture.
1112 GMT (7:12 a.m. EDT)
The Cygnus spacecraft is in "free drift" mode and configured for release.
1107 GMT (7:07 a.m. EDT)
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.

1043 GMT (6:43 a.m. EDT)
The Cygnus spacecraft is now in the release position about 30 feet from the space station.
1040 GMT (6:40 a.m. EDT)
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. Orbital says the Cygnus as acquired star tracker data, which allows it to navigate in space.
1016 GMT (6:16 a.m. EDT)
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.

The Cygnus spacecraft spent nearly 23 days mated to the complex, delivering more than 1,300 pounds of cargo and taking away more than a metric ton of trash.

On the home stretch of a highly successful demonstration flight, the Orbital Sciences Cygnus spacecraft will be robotically plucked from its berthing port on the International Space Station and released Tuesday to begin its destructive descent over the Pacific Ocean.

The automated cargo freighter, concluding its first visit to the space station, delivered more than 1,300 pounds of supplies to the complex Sept. 29. At the end of its mission, the Cygnus spacecraft is designed to carry trash and unneeded equipment and burn up during re-entry into the atmosphere.

Astronauts closed hatches between the spacious Cygnus pressurized module and the space station's Harmony module at 6:42 a.m. EDT (1042 GMT) Monday. Flight engineers Karen Nyberg, Luca Parmitano and Michael Hopkins prepared for the departure by configuring the vestibule connecting Harmony and Cygnus for depressurization, then the trio reviewed procedures for the unberthing and release of the robotic spaceship, according to an update posted on NASA's website.

The space station's 57.7-foot-long robot arm will pull the Cygnus spacecraft away from Harmony at about 6 a.m. EDT (1000 GMT) Tuesday, once bolts fastening the cargo carrier to the space station are driven open.

The robot arm will maneuver the Cygnus spacecraft to a point about 30 feet beneath the space station, then release the vehicle at about 7:30 a.m. EDT (1130 GMT).

The Cygnus spacecraft will pulse its rocket jets several times to put itself on a safe trajectory away from the space station and prepare for two de-orbit burns Wednesday to guide the expendable spacecraft to a safe re-entry over the South Pacific Ocean between New Zealand and South America.

The first de-orbit burn is scheduled for 9:06 a.m. EDT (1306 GMT) Wednesday, followed by a final rocket firing at 1:41 p.m. EDT (1741 GMT) to slow the craft's velocity enough to drop from orbit and fall into the atmosphere.

Re-entry is expected at about 2:18 p.m. EDT (1818 GMT). The bulk of the spacecraft will disintegrate and burn up in the atmosphere, and surviving fragments will splash down in the remote South Pacific.

The commercial Cygnus spacecraft launched Sept. 18 aboard an Orbital Sciences Antares rocket. After overcoming a data discrepancy in its GPS navigation link with the space station, the Cygnus completed a near-flawless rendezvous with the outpost Sept. 29.

Nyberg, Parmitano and Hopkins oversaw the unpacking of the freighter's pressurized cargo module, removing bags of food, computer gear, crew care kits and student-built experiments. The astronauts replaced the supplies with trash and other items no longer needed aboard the space station.

The first Cygnus mission is a demonstration flight under NASA's Commercial Orbital Transportation Services program, a public-private partnership between the space agency and Orbital Sciences conceived to develop a private rocket and spacecraft to restore a domestic U.S. capability to deliver cargo to the space station after the retirement of the space shuttle.

NASA selected Orbital Sciences and SpaceX for the job. SpaceX accomplished its demonstration flight to the station in May 2012 and has since begun operational resupply missions.

Orbital's first operational Cygnus flight is set for launch in a window from Dec. 15 to Dec. 21.

Orbital Sciences says the Cygnus spacecraft has performed well during its 23-day stay at the space station.

"The near flawless in-orbit performance was a great testament to the work of the Orbital/NASA team that designed, built, tested and operated the spacecraft, and also a clear indication of how capable and versatile an in-space logistics vehicle we now have for both space station cargo delivery and other advanced space missions," said David Thompson, Orbital's chairman and CEO.

Working in orbit 250 miles above Earth, astronauts aboard the International Space Station have finished unpacking 1,300 pounds of supplies from the commercial Cygnus cargo craft after its historic arrival at the complex last month.

Orbital Sciences Corp., owner and operator of the Cygnus spacecraft, announced Tuesday the six-person Expedition 37 crew has finished unloading the food, computer equipment, supplies and student experiments delivered to the space station when the commercial resupply freighter reached the outpost Sept. 29.

Space station flight engineers Karen Nyberg, Luca Parmitano and Michael Hopkins did most of the work, and the astronauts have started packing trash back inside the Cygnus spacecraft's pressurized compartment for disposal at the end of its mission.

The first layer of trash has been placed inside the Cygnus cargo module, with the second layer being added this week. A third layer of equipment and bags for disposal will be installed next week, followed by closeouts of the spaceship's pressurized section.

The Cygnus cargo module, built by Thales Alenia Space in Italy, has an internal volume of about 667 cubic feet, about the size of a mid-sized moving truck.

The Cygnus should get rid of about 2,400 pounds of trash from the space station.

Work on the space station continues despite the partial shutdown of the federal government due to a funding impasse in Congress. About 97 percent of NASA's civil servant workforce was furloughed by the shutdown, but the space agency granted exemptions for space station flight controllers.

The Cygnus spacecraft is set to leave the space station is scheduled for Oct. 22, and its departure is not affected by the government shutdown. Orbital Sciences oversees the operations of its Cygnus spacecraft from a control center at the company's headquarters in Dulles, Va.

Two days later, on Oct. 24, Orbital engineers will command the spacecraft to fire its rocket thrusters for a de-orbit burn, guiding Cygnus to a re-entry over the remote South Pacific Ocean. Like Russian Progress supply ship, Japan's H-2 Transfer Vehicle and Europe's Automated Transfer Vehicle, the Cygnus spacecraft is designed to burn up in the atmosphere.

1245 GMT (8:45 a.m. EDT)
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 8:44 a.m. EDT (1244 GMT) as the space station flew over the Indian Ocean southwest of Indonesia.

1237 GMT (8:37 a.m. EDT)
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.
1206 GMT (8:06 a.m. EDT)
The station crew is now beginning the work to move Cygnus into the so-called "pre-install" position near the Harmony module.
1155 GMT (7:55 a.m. EDT)
The next operations this morning will align Cygnus spacecraft with its berthing port on the Harmony module.

Teams are inspecting the Cygnus hatch and berthing mechanism are debris and obstructions, but no signs of any problems are reported.

1120 GMT (7:20 a.m. EDT)
Teams have resolved a glitch with the robot arm that occurred as it grappled Cygnus, and now the arm has latched to mate a power and data link - in addition to a mechanical connection - between the two vehicles.

Over the next 90 minutes or so, 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 bolts will drive closed to create a sturdy connection between Harmony and Cygnus.

The astronauts plan to open hatches into the Cygnus spacecraft's cargo module Monday around 5:55 a.m. EDT (0955 GMT).

1107 GMT (7:07 a.m. EDT)
Mission control reports the official capture time was 7 a.m. EDT (1100 GMT) as the space station and Cygnus flew over the Indian Ocean.

We're really proud to have the G. David Low aboard the ISS today," said CAPCOM Cady Coleman from Houston.

Orbital Sciences christened the first Cygnus spacecraft the "G. David Low" after the late astronaut and Orbital executive. Low was a three-time space shuttle astronaut and spearheaded Orbital's efforts to develop a commercial resupply system for the space station.

"I would like to say, first of all, I was honored to be allowed to be part of this today," said Luca Parmitano, who controlled the robot arm during the manual capture sequence. "It was really a pleasure and it was a privilege to work today with all the teams on the ground, both the teams from Houston, of course, from Orbital and from here on the station."

"It was great to see you in action," Coleman replied. "It was really everything we could have wished for today."

1101 GMT (7:01 a.m. EDT)
Parmitano reports a good capture with the robot arm!

"We see a good capture down here," said astronaut Cady Coleman, CAPCOM in mission control Houston. "That's a long time coming. Looks great."

1059 GMT (6:59 a.m. EDT)
The arm is in motion under the control of astronaut Luca Parmitano.
1058 GMT (6:58 a.m. EDT)
The astronauts in the space station's windowed cupola work station are waiting for an error message to clear before moving the robot arm to capture Cygnus.
1055 GMT (6:55 a.m. EDT)
Mission control in Houston just gave the final "go" for Luca Parmitano to grapple the Cygnus spacecraft.
1053 GMT (6:53 a.m. EDT)
Orbital Sciences, the operator of Cygnus, is ready for Cygnus capture. And the space station crew just told mission control they are ready for capture as well.
1050 GMT (6:50 a.m. EDT)
Cygnus has slowed its approach, now stationkeeping about 12 meters, or 36 feet, away from the International Space Station.

Teams will be polled in the next few minutes to verify all systems are ready for Luca Parmitano to take manual control of the station's Canadian robot arm to grapple Cygnus.

1046 GMT (6:46 a.m. EDT)
Mission control says Cygnus will be in position for a revised capture time of 7 a.m. EDT (1100 GMT).
1045 GMT (6:45 a.m. EDT)
Range is now about 21 meters, or 69 feet.
1043 GMT (6:43 a.m. EDT)
Range is now about 25 meters, or 82 feet.
1041 GMT (6:41 a.m. EDT)
The last phase of this morning's rendezvous is underway! Cygnus is moving along the R-bar, the imaginary line between the space station and the center of the Earth.

Its destination is a capture box about 32 feet below the space station.

1040 GMT (6:40 a.m. EDT)
Mission control is "go" for departure of Cygnus to the capture point just 10 meters, or about 32 feet, from the space station.
1027 GMT (6:27 a.m. EDT)
The Orbital Sciences control center in Dulles, Va., is "go" for maneuvering Cygnus its capture box. Still awaiting NASA's approval.
1024 GMT (6:24 a.m. EDT)
Mission control says the Cygnus rendezvous is running about 15 minutes ahead of the timeline, but engineers are still reviewing data before giving approval for the final maneuvers to the capture point.
1022 GMT (6:22 a.m. EDT)
Cygnus has arrived at a hold point 30 meters, or 98 feet, beneath the International Space Station. It will pause here for a few minutes before pressing on to the capture point about 36 feet from the space station.
1009 GMT (6:09 a.m. EDT)
Range is less than 90 meters, or 295 feet.
1004 GMT (6:04 a.m. EDT)
Completing its final demo task a little early, the Cygnus spacecraft has completed its last test objective by firing its laser navigation system toward a single reflector on the space station.

Final approval for grapple still depends on NASA's concurrence with the results of the demo data.

Range is now 133 meters, or 436 feet.

0958 GMT (5:58 a.m. EDT)
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.

Along the way, at a range of about 55 meters, Cygnus will do its final rendezvous demo, firing its laser sensors toward a single reflector mounted on the space station's Japanese Kibo lab module to test its precision.

0955 GMT (5:55 a.m. EDT)
Italian astronaut Luca Parmitano, who will man the robot arm controls for today's capture of Cygnus, just tweeted: "#Cygnus working perfectly and holding @220M! I was happy to be the first to shout 'there it is!'"
0951 GMT (5:51 a.m. EDT)
Mission control in Houston is satisfied with the Cygnus spacecraft's performance so far this morning, and NASA is "go" for the automated delivery vehicle to continue approaching the space station in a few minutes.
0929 GMT (5:29 a.m. EDT)
After returning to its hold point 250 meters, or 820 feet, below the space station, Cygnus resumed its movement toward the outpost and astronaut Karen Nyberg ordered the 16.8-foot-long spaceship to hold about 220 meters, or 722 feet, away from the space station.

Mission control sees the spacecraft slowing its approach.

The spacecraft will hold at the 220-meter point for about 30 minutes while engineers at space station mission control in Houston and Cygnus mission control in Dulles, Va., look over data coming down from the cargo vehicle.

The space station flight director will soon. poll controllers for a "go" to move Cygnus inside the space station's keep-out sphere. The departure of Cygnus from its current position is expected around 6:17 a.m. EDT (1017 GMT) if things proceed on schedule.

The spacecraft's next destination is a 30-meter, or 98-foot, hold point. The spacecraft's LIDAR laser sensors will zero in on one reflector on the space station's Kibo lab module to demonstrate precision guidance.

After another check of the status of Cygnus, ground teams should approve the vehicle to continue its laser-guided rendezvous up to a point about 30 feet from the space station, close enough for astronaut Luca Parmitano to snag the spacecraft with the space station's robot arm.

0916 GMT (5:16 a.m. EDT)
Space station flight engineer Karen Nyberg has has sent the retreat command to the Cygnus spacecraft, and mission control sees the cargo ship moving back away from the complex as expected.
0914 GMT (5:14 a.m. EDT)
Cygnus will soon resume its approach briefly before astronaut Karen Nyberg will order the spaceship to retreat back to the 820-foot hold point.
0907 GMT (5:07 a.m. EDT)
Cygnus has arrived at a hold point 250 meters, or 820 feet, directly below the space station as the two vehicles fly about 260 miles above the west coast of Africa.

Coming up in a few minutes, Cygnus will resume moving toward the space station, and the astronauts aboard the outpost will use a command panel to order Cygnus to retreat, demonstrating the crew can send emergency commands to the visiting vehicle in case it runs into trouble.

After retreating back to the 250-meter hold point, Cygnus will again start moving toward the space station before a hold command is issued at 220 meters, or 722 feet.

Once those demos are completed, and if all systems are healthy, mission control centers in Houston and Dulles, Va., will give the "go" to press on inside the space station's keep-out sphere, an imaginary zone 200 meters, or 656 feet, around the complex.

0854 GMT (4:54 a.m. EDT)
The seventh milestone in the Cygnus spacecraft's matrix of demos has been completed. The freighter's three LIDAR optical navigation sensors have locked on to the space station.

The spacecraft has completed a course-correction maneuver and is on track to arrive at a point 820 feet below the space station at about 5:10 a.m. EDT (0910 GMT).

0837 GMT (4:37 a.m. EDT)
All systems are functioning as designed as the Orbital Sciences Cygnus spacecraft continues its approach under the International Space Station.

The space freighter just completed a major rendezvous maneuver to guide Cygnus toward a point on the "R-bar" about 820 feet directly below the space station.

NASA reports the automated spacecraft, making its first flight to the station, has completed six of 10 milestones required to prove out Cygnus propulsion, guidance and navigation systems before mission control gives the green light to move in to an approach corridor just 30 feet below the complex.

0135 GMT (9:35 p.m. EDT Sat.)
Orbital Sciences reports the International Space Station and the Cygnus spacecraft have established a good communications connection in orbit, and the navigation error which cut short a rendezvous last weekend has been resolved.

Engineers uploaded a software fix a few days ago to overcome a data discrepancy in GPS navigation data. The computer on the Cygnus spacecraft, packed with 1,543 pounds of supplies and experiments, compares position data from Cygnus and the space station to guide itself toward the complex, ultimately reaching a point about 820 feet below the outpost.

The Cygnus will then 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 Luca Parmitano will take control of the lab's robot arm to reach out and grapple the free-floating 16.8-foot-long spacecraft at about 1115 GMT (7:15 a.m. EDT) and move it to a berthing port on the space station a few hours later.

NASA requires Cygnus complete several key demonstrations during Sunday's rendezvous, including an on-board targeting demo, a test of a control panel inside the space station to prove the astronauts can send emergency commands, and the activation and checkout of the LIDAR navigation sensor.

Mission managers today approved plans for the commercial Cygnus cargo craft to approach the International Space Station on Sunday, demonstrate its ability to navigate and maneuver nearby, and slow to a hover just below the complex while astronaut Luca Parmitano grapples the automated spaceship with a robot arm.

Orbital Sciences Corp. engineers have overcome the problem that cut short the spacecraft's first rendezvous Sept. 22, uplinking a software patch to Cygnus to resolve a roll-over discrepancy in GPS navigation data between the cargo craft and the space station.

The Cygnus approached within a few miles of the complex Sept. 22 and established two-day communications with the space station, but officials aborted the rendezvous when the data glitch appeared.

Managers earlier this week pushed back the Cygnus arrival until after the Wednesday docking of a Soyuz capsule with two cosmonauts and and a NASA astronaut.

Barry Beneski, an Orbital spokesperson, said ground controllers have uploaded and fully tested the software fix and expect no problems with the GPS system Sunday.

You can view live coverage of the Cygnus rendezvous here beginning at 4:30 a.m. EDT (0830 GMT) Sunday, with capture by Parmitano scheduled for 7:15 a.m. EDT (1115 GMT). A few hours later, the robot arm will put the Cygnus spacecraft on a berthing port on the space station's Harmony module.

Orbital Sciences Corp. says the earliest its commercial Cygnus cargo craft could reach the space station is now Sunday.

"The Cygnus spacecraft remains healthy in-orbit, with all major onboard systems performing as expected," Orbital said in a statement today. "Over the past several days, the Cygnus engineering team has developed, validated and uploaded the one-line software 'patch' that resolved the GPS data roll-over discrepancy that was identified during the initial approach to the ISS last Saturday."

Officials are discussing the best time to attempt the rendezvous, with the earliest opportunity now Sunday, pending final approvals from Orbital and NASA.

The spacecraft's first approach was aborted Saturday, and managers decided to put off another rendezvous until after the arrival of three fresh crew members aboard a Russian Soyuz spacecraft. Two Russian cosmonauts and a NASA astronaut successful blasted off from Kazakhstan yesterday and reached the complex overnight after a fast-track six-hour rendezvous.

Orbital says the Cygnus spacecraft is currently about 2,400 kilometers, or about 1,500 miles, behind the space station. The automated spacecraft will fire thrusters this evening to begin setting up for a second rendezvous opportunity Sunday.

With tonight's successful docking of a Soyuz capsule with three new long-duration residents for the International Space Station, the next vehicle to arrive at the complex is the Orbital Sciences Corp. Cygnus cargo freighter.

The Cygnus spacecraft, on its first test flight, launched Sept. 18 from Virginia and was supposed to rendezvous with the outpost Sunday, but the approach was aborted after a technical snafu involving incompatible navigation data between Cygnus and the space station.

Orbital Sciences developed a software fix for the commercial resupply vehicle, but officials opted to delay the Cygnus rendezvous until after the Soyuz launch and docking to give engineers more time to work on the problem and ensure control teams are fully rested.

Officials said Monday the earliest the Cygnus spacecraft could arrive at the space station was Saturday morning, U.S. time, but managers planned to meet again Thursday and Friday to formally settle on the date for a second rendezvous attempt.

Joel Montalbano, NASA's deputy space station program manager, said Wednesday the next rendezvous would occur no earlier than Sunday. Montalbano make the remarks in an interview from the Baikonur Cosmodrome aired on NASA TV following the Soyuz launch.

But meetings Thursday and Friday will officially determine the next course of action for Cygnus, including its arrival date at the space station, a NASA spokesperson said.

Orbital Sciences Corp. and NASA decided today to push back the arrival of the commercial Cygnus cargo craft at the International Space Station until at least Saturday.

The delay gives ground crews more time to prepare for a second rendezvous attempt after officials called off an approach early Sunday due to a data mismatch in the navigation data link between Cygnus and the space station.

A rendezvous Saturday comes after the scheduled launch and docking of three new space station residents aboard a Russian Soyuz capsule Wednesday. Space station managers do not schedule vehicle arrivals and departures too close to each other to allow time for technical reconfigurations and crew rest between major operations.

In an update posted on its website, Orbital said an exact schedule for the arrival of the Cygnus spacecraft will be determined following the Soyuz docking.

"Over the past 24 hours, the Orbital team developed and tested a software fix for the data format mismatch that necessitated a postponement of the first rendezvous operation that was scheduled for the early morning of September 22," Orbital said in a statement on its website. "However, that process, together with the impending Soyuz crew operations, resulted in a tight schedule to the point that both Orbital and NASA felt it was the right decision to postpone the Cygnus approach and rendezvous until after Soyuz operations."

The Cygnus spacecraft is on a demonstration mission to prove the cargo ship can safely approach and berth with the space station. Orbital Sciences has a $1.9 billion contract for eight further Cygnus missions to deliver supplies to the complex through 2016.

"This new schedule will allow the Orbital operations team to carefully plan and be well-rested before restarting the critical final approach to the space station. Meanwhile, Cygnus has all the resources needed to remain in orbit for an extended period of time," said Frank Culbertson, Orbital's vice president of advanced programs.

1505 GMT (11:05 a.m. EDT)
NASA and Orbital Sciences are replanning the Cygnus spacecraft's rendezvous with the International Space Station, now set for early Tuesday morning.

Orbital says a software update to resolve the glitch in the Cygnus freighter's communications and navigation link with the space station will be installed and tested on a ground simulator today. If the testing goes well, the software patch will be uploaded to the Cygnus spacecraft overnight tonight.

"Once this has been accomplished and verified, the current plan is for Cygnus to begin a second rendezvous and approach late Monday night, with final approach to the ISS and grapple taking place early Tuesday morning," Orbital said in a statement.

The spacecraft, making its first flight in orbit, remains otherwise healthy, Orbital said.

0822 GMT (4:22 a.m. EDT)
NASA and Orbital Sciences have issued a joint statement on this morning's status:

"Orbital Sciences has confirmed that this morning, around 1:30 a.m. EDT, its Cygnus spacecraft established direct data contact with the International Space Station (ISS) and found that some of the data received had values that it did not expect, causing Cygnus to reject the data. This mandated an interruption of the approach sequence.

"Orbital has subsequently found the causes of this discrepancy and is developing a software fix. The minimum turnaround time to resume the approach to the ISS following an interruption such as this is approximately 48 hours due to orbital mechanics of the approach trajectory."

0750 GMT (3:50 a.m. EDT)
Today's arrival of the Cygnus spacecraft at the International Space Station has been postponed due to a problem uncovered during this morning's approach to the 450-ton complex.

The approach was aborted a few minutes ago due to an issue with the unmanned spacecraft's GPS navigation system. Mission control in Houston informed the crew of the postponement at about 3:30 a.m. EDT (0730 GMT).

The GPS navigation system is used for the freighter's "far-field" rendezvous until the Cygnus spacecraft switches to a laser-guided rendezvous sensor for the final approach within 820 feet of the complex.

The Cygnus spacecraft's guidance system uses relative GPS navigation by comparing its location with navigation data beamed to the Cygnus from the space station using a Japanese communications system.

The craft will soon pass about 2.5 miles below the space station and set up for another rendezvous attempt no earlier than Tuesday, mission control radioed the crew.

The test of the relative GPS system was one of eight demonstrations in the Cygnus flight plan for today, all of which must be satisfied before NASA gives the green light for the 17-foot-long, 10-foot-diameter spacecraft to move to a capture point about 30 feet from the outpost to be grabbed the lab's robotic arm.

No problems were reported with the Cygnus spacecraft since its Wednesday launch from Wallops Island, Va.

Officials said before launch the cargo transporter carries enough propellant to loiter in orbit for several weeks before arriving at the space station, giving ground teams at Orbital Sciences Corp.'s headquarters in Dulles, Va., time to resolve any problems.

The Cygnus spacecraft is on a demonstration mission under NASA's Commercial Orbital Transportation Services program, a public-private partnership in which Orbital Sciences and NASA jointly funded development of the cargo craft and its Antares rocket booster.

Orbital has signed up for eight operational missions beyond the current flight under a $1.9 billion contract through 2016.

Orbital Sciences says the Cygnus spacecraft is performing well on its second day in space, following a picture-perfect blastoff from Virginia yesterday.

Two orbit-raising "Delta-V" burns have been conducted using the Cygnus main engine since launch, and the freighter accomplished the first of 10 demonstration milestones on its way to the International Space Station.

"The team is packaging data from the test for NASA's review and approval, which is expected to be received today," Orbital said in a statement.

Another orbit-raising burn is scheduled later today.

A privately-owned spaceship built by Orbital Sciences Corp. made an Earth-rattling trip into orbit from Virginia on Wednesday, starting a four-day chase of the International Space Station to close out a nearly $700 million NASA program to foster a fleet of commercial spaceships to replace capabilities lost with the space shuttle's retirement.

Read our full story.

2145 GMT (5:45 p.m. EDT)
A seven-minute firing of the Cygnus spacecraft's main thruster has been completed as planned, according to Orbital Sciences.

This maneuver changed the freighter's velocity by nearly 100 mph and sets up the spacecraft for the first of 10 demonstration maneuvers this evening, in which the Cygnus will prove its ability to transition to free drift and abort an approach to the International Space Station.

NASA and Orbital Sciences planned 10 demo objectives on the Cygnus mission before it is approved to move toward the imaginary capture box underneath the space station, where European astronaut will grab it with the lab's Canadian robotic arm.

1720 GMT (1:20 p.m. EDT)
Frank Culbertson, vice president of advanced programs at Orbital Sciences, said the Antares rocket hit a near-perfect orbit during today's launch, releasing the Cygnus spacecraft in an orbit with a high point of 179 miles and a low point of 159 miles.

The Cygnus spacecraft extended its two solar array wings shortly after deployment from the Antares solid-fueled second stage, and the freighter's propulsion system pressurized as planned to prepare the vehicle for the first in a series of engine firings to reach the International Space Station.

"The solar arrays have deployed, and we're getting good power from them," Culbertson said. "The propulsion system has activated, and we're getting good stable control of the spacecraft, pointing at the sun, and getting ready to execute the maneuvers to get to the International Space Station in four days."

The first engine burn is scheduled for approximately 4 p.m. EDT (2000 GMT) to adjust the Cygnus spacecraft's orbit and set it up for its chase of the space station. "This was hard," Culbertson said. "It's difficult to get a rocket off the launch pad. There are a lot of things that have to come together no matter how many times you do it."

1526 GMT (11:26 a.m. EDT)
Deployment of the Cygnus solar arrays has been completed, and the craft's propulsion system has been activated.
1520 GMT (11:20 a.m. EDT)
Orbital Sciences says solar array deployment has begun. The Cygnus solar arrays will take between 20 and 30 minutes to unfurl.
1511 GMT (11:11 a.m. EDT)
Deployment of the Cygnus solar arrays, manufactured by Dutch Space, should begin shortly.
1508 GMT (11:08 a.m. EDT)
Cygnus separation confirmed!
1507 GMT (11:07 a.m. EDT)
Engineers report the rocket reached a good orbit.
1506 GMT (11:06 a.m. EDT)
Antares is in orbit! The Castor 30A upper stage motor shut down on time and has reached orbit. Deployment of the 9,000-pound Cygnus cargo craft occurs at about T+plus 10 minutes.
1505 GMT (11:05 a.m. EDT)
T+plus 7 minutes, 50 seconds. Approaching 17,000 mph.
1505 GMT (11:05 a.m. EDT)
T+plus 7 minutes, 30 seconds. About 30 seconds remaining in the second stage burn.
1505 GMT (11:05 a.m. EDT)
T+plus 7 minutes. Motor pressure is nominal.
1504 GMT (11:04 a.m. EDT)
T+plus 6 minutes, 20 seconds. Attitude, power and steering all nominal aboard Antares.
1504 GMT (11:04 a.m. EDT)
T+plus 6 minutes. Systems are reported to be in good shape as the Castor 30A fires with 90,000 pounds of thrust.
1503 GMT (11:03 a.m. EDT)
T+plus 5 minutes, 35 seconds. Orbital Sciences reports a good separation of the payload fairing and ignition of the Antares second stage Castor 30A motor built by ATK for a 155-second burn to inject the rocket into orbit.

1502 GMT (11:02 a.m. EDT)
T+plus 4 minutes, 30 seconds. A smooth flight being reported by launch control.
1502 GMT (11:02 a.m. EDT)
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 98 seconds, in which the rocket will ascend to an altitude of 189 kilometers, or 117 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.

1501 GMT (11:01 a.m. EDT)
T+plus 3 minutes, 30 seconds. Altitude 250,000 feet, Pressure and steering are nominal.
1501 GMT (11:01 a.m. EDT)
T+plus 3 minutes. The rocket's guidance system continues flying the rocket on course, and all systems are reported to be in good shape. The first stage engines will shut down at T+plus 3 minutes, 53 seconds, followed a few seconds later be separation of the liquid-fueled first stage.
1500 GMT (11:00 a.m. EDT)
T+plus 2 minutes, 15 seconds. Altitude about 100,000 feet.
1500 GMT (11:00 a.m. EDT)
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.
1459 GMT (10:59 a.m. EDT)
T+plus 90 seconds. Power is nominal, engines are nominal.
1459 GMT (10:59 a.m. EDT)
T+plus 60 seconds. The rocket is flying steady and accelerating near the speed of sound, sending a thunderous roar across the Eastern Shore.
1458 GMT (10:58 a.m. EDT)
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 107.8 degrees - over the Atlantic Ocean.
1458 GMT (10:58 a.m. EDT)
LIFTOFF of the Antares rocket, boosting 1,500 pounds of supplies on a four-day journey to the International Space Station and demonstrating the Orbital Sciences Cygnus cargo delivery spaceship.
1457 GMT (10:57 a.m. EDT)
T-minus 5 seconds. Transporter erector is swinging back. Standing by for ignition!
1457 GMT (10:57 a.m. EDT)
T-minus 15 seconds. The engine steering check is underway.
1457 GMT (10:57 a.m. EDT)
T-minus 30 seconds and counting to second flight of Antares.
1457 GMT (10:57 a.m. EDT)
T-minus 45 seconds.
1457 GMT (10:57 a.m. EDT)
T-minus 60 seconds. High speed video cameras are activating.
1456 GMT (10:56 a.m. EDT)
T-minus 90 seconds.
1456 GMT (10:56 a.m. EDT)
T-minus 2 minutes. Flight computer is ready. The rocket's propellant tanks are pressurizing now.
1455 GMT (10:55 a.m. EDT)
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.

1454 GMT (10:54 a.m. EDT)
T-minus 3 minutes, 30 seconds. The auto sequence has started.
1454 GMT (10:54 a.m. EDT)
T-minus 4 minutes and counting. The automatic countdown sequence begins in a few seconds.
1453 GMT (10:53 a.m. EDT)
T-minus 5 minutes and counting. The rocket is now running on its own battery.
2054 GMT (4:54 p.m. EDT)
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.
1451 GMT (10:51 a.m. EDT)
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.
1450 GMT (10:50 a.m. EDT)
T-minus 8 minute and counting. No problems are reported in the countdown and the weather continues to look favorable for liftoff at 10:58 a.m. EDT.
1448 GMT (10:48 a.m. EDT)
T-minus 10 minutes and counting. The next step in the engine chilldown procedure is now beginning. And final vehicle arming is underway.
1447 GMT (10:47 a.m. EDT)
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.
1445 GMT (10:45 a.m. EDT)
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.

1444 GMT (10:44 a.m. EDT)
T-minus 14 minutes and counting. The roughly 9,000-pound Cygnus spacecraft, christened the "G. David Low" after the late former astronaut and Orbital Sciences executive, is running on internal power and is in good shape for launch.
1442 GMT (10:42 a.m. EDT)
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.
1440 GMT (10:40 a.m. EDT)
Upper level winds are reported green.

An Orbital Sciences spokesperson says the launch delay earlier this morning from 10:50 a.m. to 10:58 a.m. EDT was due to a regulator issue on the first stage fuel system.

1436 GMT (10:36 a.m. EDT)
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.

1434 GMT (10:34 a.m. EDT)
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.

1432 GMT (10:32 a.m. EDT)
The Wallops Range is now green after officials evacuated four homes near the Antares launch pad. This was to avoid a safety issue due to a concern the blast from the launch could damage public buildings.
1428 GMT (10:28 a.m. EDT)
Chilldown is underway and all systems are reported to be in good shape for an on-time launch at 10:58 a.m. EDT.
1426 GMT (10:26 a.m. EDT)
T-minus 32 minutes and counting. Loading of kerosene into the rocket is going well. The first stage's helium pressurant bottles are now submerged.
1425 GMT (10:25 a.m. EDT)
A NASA spokesperson says safety officials are working on evacuating four homes near the launch pad to remove the threat of the distance focused overpressure, which would put onlookers and nearby structures in jeopardy from the blast of the rocket.
1423 GMT (10:23 a.m. EDT)
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.
1418 GMT (10:18 a.m. EDT)
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.
1417 GMT (10:17 a.m. EDT)
Engineers have spotted a tight lanyard between the Antares rocket and its Transporter/Erector/Launcher umbilical arm. They have requested the TEL slightly toward the launcher to give the line some slack.
1416 GMT (10:16 a.m. EDT)
The launch team has verified good telemetry links between the rocket and ground teams.
1413 GMT (10:13 a.m. EDT)
T-minus 45 minutes and counting. The launch team is loading the flight trajectory file into the Antares flight computer.
1408 GMT (10:08 a.m. EDT)
Liquid oxygen is flowing into the Antares rocket's Ukrainian-built first stage at a rate of 150 gallons per minute.
1408 GMT (10:08 a.m. EDT)
The Cygnus spacecraft on this flight has a launch mass of approximately 4,100 kilograms, or 9,038 pounds. 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:

1405 GMT (10:05 a.m. EDT)
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.

1403 GMT (10:03 a.m. EDT)
The Wallops Range is still red due to the distance focused overpressure rule. The distance focused overpressure rule addresses concerns that the blast of launch could damage nearby structures.

Officials are still optimistic the concern will be lifted in time for launch, and there are backup procedures in place to evacuate nearby public buildings to remove the threat of a blast damaging a building with occupants.

1400 GMT (10:00 a.m. EDT)
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.

1358 GMT (9:58 a.m. EDT)
T-minus 60 minutes and counting. The launch window extends until 11:05 a.m. EDT.

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.

1355 GMT (9:55 a.m. EDT)
Today's launch is carrying Orbital's first Cygnus spacecraft to orbit.

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.

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 get a signal from the spacecraft about a half-hour after launch that the panels have deployed.

1350 GMT (9:50 a.m. EDT)
Fueling operations continue for today's liftoff at 10:50 a.m. EDT (1450 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.

1343 GMT (9:43 a.m. EDT)
Orbital Sciences confirms fueling is underway.
1328 GMT (9:28 a.m. EDT)
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 298 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, 50-second burn.

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

1325 GMT (9:25 a.m. EDT)
NEW LAUNCH TIME. Liftoff is reset for 10:58 a.m. EDT (1458 GMT).
1305 GMT (9:05 a.m. EDT)
The countdown has entered a second built-in hold for 15 minutes. This hold allows the launch team to finish up open work before giving the "go" for fueling, which is supposed to begin at 9:20 a.m. EDT (1320 GMT).
1259 GMT (8:59 a.m. EDT)
The launch team is looking at an issue with the RP-1 fuel system on the Antares rocket's first stage, which is designed by Yuzhnoye and manufactured by Yuzhmash in Ukraine.
1255 GMT (8:55 a.m. EDT)
Here's the launch timeline the Antares rocket will follow during launch.

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1246 GMT (8:46 a.m. EDT)
The next report on the distance focused overpressure rule is expected in about 20 minutes. The launch team believes the conditions will improve as the morning sun helps burn off clouds in the area, which aggravate the issue.
1244 GMT (8:44 a.m. EDT)
Chilldown of the Antares launch pad fueling system continues, and the launch team has finished testing of the rocket's ordnance systems. No problems are being reported in the countdown at this point.
1232 GMT (8:32 a.m. EDT)
The Wallops range is "red" for the the distance focused overpressure rule. The launch team will receive occasional updates on the status of this rule through the countdown, but indications are the conditions are trending toward "green" as launch time approaches.

The distance field overpressure rule addresses concerns that the blast of launch could damage nearby structures.

1230 GMT (8:30 a.m. EDT)
The launch team has completed testing of the rocket's flight termination system, and countdown is now moving into activating the vehicle's pyrotechnic ordnance systems in a few minutes.
1209 GMT (8:09 a.m. EDT)
The launch team has resolved an issue in obtaining a lock on the Antares rocket's telemetry signal from tracking stations.

Chilldown of the liquid oxygen loading system is continuing as engineers prepare to power up the flight termination system for testing.

1205 GMT (8:05 a.m. EDT)
The latest weather forecast issued this morning continues to show a 75 percent chance of acceptable conditions at the time of launch. It is a chilly, but sunny morning here at Wallops Flight Facility.
1145 GMT (7:45 a.m. EDT)
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.

1130 GMT (7:30 a.m. EDT)
Management has arrived on console to begin the final countdown procedures after resuming the countdown following the first of two planned 15-minute built-in holds.

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.

The launch team will soon begin the process of priming the plumbing on the launch facility for loading of super-cold liquid oxygen, which begins at about 9:20 a.m. EDT (1320 GMT).

0745 GMT (3:45 a.m. EDT)
The countdown began on time to begin final preps for this morning's 10:50 a.m. EDT blastoff of the 13-story Antares rocket from the Mid-Atlantic Regional Spaceport at NASA's Wallops Flight Facility in Virginia.

Follow activities with this countdown timeline.

The mission will be the second launch of the Orbital Sciences Antares rocket after a successful test launch in April proved the two-stage rocket could deliver payloads into low Earth orbit.

Mike Pinkston, the Antares program director at Orbital, said engineers made very few changes to the design of the launch vehicle after the April mission.

The rocket's solid-fueled upper stage, provided by ATK, provided a bit less performance than anticipated, Pinkston said, adding it is difficult for engineers to predict how a solid rocket motor will perform in flight before testing it in the environment.

Pinkston said software engineers tweaked code in the Antares guidance computer to account for the performance data obtained in the April test flight.

Technicians also modified some of the umbilical connections between the Antares rocket and its Transporter/Erector/Launcher system, which services as a support tower during the countdown.

0530 GMT (1:30 a.m. EDT)
One minute after an Atlas 5 rocket is scheduled to blast off from Florida, the Antares launch team will get to work inside the launch control center at Wallops Flight Facility in Virginia with the start of the countdown toward liftoff at 10:50:14 a.m. EDT (1450:14 GMT).

The call-to-stations for the engineers on the launch team is scheduled for 2:35 a.m. EDT (0635 GMT), with voice checks and opening of the prelaunch checklist scheduled for 3:05 a.m. EDT (0705 GMT).

Workers will clear the launch pad at about 4:20 a.m. EDT (0820 GMT), followed by vehicle power-up at 4:55 a.m. EDT (0855 GMT).

Chilldown of the Antares liquid oxygen loading system begins at 7:35 a.m. EDT (1135 GMT) in preparation for propellant loading at 9:20 a.m. EDT (1320 GMT).

1930 GMT (3:30 p.m. EDT)
Officials gave final approval today to press on with tomorrow's launch of the Orbital Sciences Antares rocket on a commercial flight to the International Space Station.

A Cygnus spacecraft is mounted on top of the 131-foot-tall rocket, packed with more than 1,500 pounds of supplies destined for the orbiting space station.

It is a crucial demonstration flight for Orbital Sciences, which developed the Antares and Cygnus under a public-private partnership with NASA. After the completion of the demonstration mission, Orbital will begin a series of eight operational resupply flights under a $1.9 billion contract with the space agency.

Bill Wrobel, director of NASA's Wallops Flight Facility, gave formal approval to proceed with the launch earlier today.

The weather forecast calls for a 75 percent chance of favorable conditions, with scattered clouds at 2,500 feet, a temperature around 70 degrees Fahrenheit, and winds out of the east at 9 to 14 knots. The only concern with weather is the possibility of low clouds violating launch rules, according to Sarah Daugherty, Wallops test director.

1730 GMT (1:30 p.m. EDT)
Managers gave a "go" to continue Antares launch preparations after a launch readiness review this morning uncovered no major problems that could prevent the rocket's launch toward the International Space Station on Wednesday.

Another meeting Tuesday of the Wallops Range Authority at NASA's Wallops Flight Facility will give final clearance to begin the countdown.

Liftoff of the 131-foot-tall rocket from launch pad 0A at the Mid-Atlantic Regional Spaceport is scheduled for precisely 10:50:12 a.m. EDT (1450:12 GMT), the opening of a 15-minute window timed for when the space station's flight path crosses over the launch pad on Virginia's Eastern Shore.

The preliminary weather forecast for Wednesday looks favorable.

"There is a 75 percent chance of favorable weather at the time of launch. Low clouds below 6,000 feet are the primary concern for a weather violation. If needed, multiple back-up launch opportunities are available through the end of September.

Orbital Sciences Corp. announced today the launch of its Antares rocket with the company's first functioning Cygnus cargo craft for the International Space Station will be delayed one day to change out a faulty cable.

The 13-story rocket was rolled one mile Friday from its horizontal integration facility to launch pad 0A at the Mid-Atlantic Regional Spaceport, a complex leased and operated by the Virginia Commercial Space Flight Authority. The launch pad is located at NASA's Wallops Flight Facility on Virginia's Eastern Shore.

The launch was previously scheduled for Tuesday.

"The combination of yesterday's poor weather that delayed rollout of the rocket to the launch pad and a technical issue that was identified during a combined systems test held last night involving communications between ground equipment and the rocket's flight computer drove the decision to delay the launch," Orbital Sciences posted in an update on its website.

"After comprehensive inspection and testing this morning, the problem was found and turned out to be an inoperative cable, which is being replaced," Orbital posted on its website Saturday. "Orbital will repeat the combined systems test later today."

If the test goes well, the officials said they will press on toward a target launch date Wednesday.

The 15-minute launch window Wednesday opens at 10:50 a.m. EDT (1450 GMT), timed for when the ground track of the space station's orbit crosses over the launch pad in Virginia.

Affixed to a Transporter/Erector/Launcher system mounted to a wheeled Self Propelled Modular Transporter, the two-stage rocket left its processing hangar in the predawn hours Friday and rolled about a mile to the seaside launch pad.

Designed, manufactured and installed by Martinez & Turek Inc. and ATA Engineering, the Transporter/Erector/Launcher, or TEL, provides mechanical connections between the Antares rocket and ground systems. It also serves as an integration platform for the launcher inside the horizontal integration facility.

Once at the launch pad, the Antares rocket and its transporter were hoisted vertical by a hydraulic system and placed on the launch mount.

Orbital Sciences plans a launch readiness review Monday to discuss the status of launch preparations.

The one-day launch delay will not affect the arrival of the Cygnus resupply ship at the space station, which remains set for Sept. 22, according to NASA.

The flight is a demonstration mission under NASA's Commercial Orbital Transportation Services, or COTS, program. The COTS program is a public-private cost-sharing partnership between NASA and Orbital Sciences to develop the Antares rocket and Cygnus spacecraft.

NASA's other COTS partner, SpaceX, completed its demo flight to the space station in 2012 and is now executing a dozen operational logistics missions with its Falcon 9 rocket and Dragon cargo craft.

Once Orbital clears its test hurdles, the company will begin a series of eight operational missions under contract to NASA through 2017.

Orbital Sciences Corp. is almost ready to send the first commercial Cygnus cargo freighter on a demonstration mission to the International Space Station, and NASA officials gave the green light Wednesday for engineers to begin final preparations for the test flight's Sept. 17 launch on an Antares rocket from the Virginia coastline.

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