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The first launch of the Antares rocket is a major step in a joint venture between Orbital Sciences and NASA to develop two commercial space transportation systems to resupply the space station, replacing much of the cargo-carrying capacity lost when the space shuttle retired in 2011.
"Today's successful test marks another significant milestone in NASA's plan to rely on American companies to launch supplies and astronauts to the International Space Station, bringing this important work back to the United States where it belongs," said NASA Administrator Charles Bolden in a statement.
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Hardware for the next Antares launch, which will haul a Cygnus cargo craft into orbit for a flight to the space station, is already being prepared for liftoff on another mission this summer.
"The next one is going to bring its own challenges," Culbertson said.
"Today's successful test marks another significant milestone in NASA's plan to rely on American companies to launch supplies and astronauts to the International Space Station, bringing this important work back to the United States where it belong.
"Congratulations to Orbital Sciences and the NASA team that worked alongside them for the picture-perfect launch of the Antares rocket. In addition to providing further evidence that our strategic space exploration plan is moving forward, this test also inaugurates America's newest spaceport capable of launching to the space station, opening up additional opportunities for commercial and government users.
"President Obama has presented a budget for next year that ensures the United States will remain the world leader in space exploration, and a critical part of this budget is the funding needed to advance NASA's commercial space initiative. In order to stop outsourcing American space launches, we need to have the President's budget enacted. It's a budget that's good for our economy, good for the U.S. space program -- and good for American taxpayers."
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.
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.
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.
Check out a timeline of key events during the launch.
The tower will retract a few degrees away from the rocket in the final seconds of the countdown.
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With the start of fueling, the available launch window has been shortened to 15 minutes. This is to keep the temperature of the propellant within acceptable limits, according to Mike Pinkston, Orbital's Antares program manager.
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 3 minutes.
"Wallops has been here 68 years and launched some 16000 rockets," said Bill Wrobel, director of Wallops Flight Facility. "This one is, no doubt, by far, the largest thing to ever come off the island."
Orbital Sciences has launched more than 1,000 space missions, including satellites, missiles and its Pegasus, Taurus and Minotaur satellite launch vehicles. All its rockets so far have been solid-fueled.
"It's going to be the biggest, brightest and loudest thing that's ever launched form Wallops," said Frank Culbertson, executive vice president and general manager of Orbital's advanced systems group.
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.
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.
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Coming in a few minutes will be testing of the rocket's flight termination system, which would be used to destroy the launcher if it flew off course.
The weather forecast calls for an 80 percent chance of favorable conditions for liftoff.
Like yesterday, officials will be closely watching the winds, both at the surface and aloft. The outlook predicts surface winds just below the launch rule threshold of 20 knots, and the first look at high-altitude winds show improvement over yesterday.
But a series of weather balloons will be launched every hour throughout the countdown to monitor upper level winds.
Right now, teams have evacuated launch pad 0A at the Mid-Atlantic Regional Spaceport ahead of power-up of the Antares rocket for prelaunch testing.
Weather at the launch base was favorable, but conditions high above coastal Virginia were not within preset rules.
Brisk winds of up to 140 mph streamed over the rocket's Virginia launch pad Saturday after the passage of a cold front overnight, raising concerns that debris from the 131-foot-tall rocket could fall on populated areas in the event of an explosion shortly after liftoff.
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Calling off the launch before fueling preserves the opportunity to try again Sunday at 5 p.m. EDT (2100 GMT).
All systems on the Antares rocket are in good shape.
A weather briefing a few minutes ago showed the upper level winds tomorrow should be less severe.
The latest weather balloon showed winds between 25,000 feet and 40,000 feet of up to 140 mph out of the southwest. One concern is the upper level winds could blow debris into populated areas if there is an accident shortly after liftoff.
The countdown clock continues to hold at T-minus 90 minutes, and the countdown would have to pick up at 4:40 p.m. EDT to support the new launch time.
Weather balloons are launched regularly throughout the countdown to keep track of upper level winds. A fresh set of balloon data should be available in time to evaluate the winds again before deciding on whether to proceed with the 6:10 p.m. launch time.
Once fueling of the Antares rocket gets underway, the launch window is restricted to just 15 minutes due to concerns over the proper temperature conditioning of the first stage's liquid propellant.
Chilldown of the launch pad's liquid oxygen fueling lines is complete, and the launch team has overcome a glitch in the vehicle's telemetry system.
Check out a map showing the visibility. And Orbital Sciences has posted a sampling of viewing opportunities at landmarks across the region.
Officials continue to monitor upper level winds, and the launch team will decide around 3:30 p.m. EDT (1930 GMT) whether to proceed with a launch around 5 p.m. or target a launch time later in the window closer to 7 p.m.
Alignment of the Antares rocket's guidance and navigation system is now underway, chilldown of the main sub-cooler with liquid nitrogen has begun.
The only concern being watched now are upper level winds. A cold front quickly pushed through the Wallops area overnight, bringing a strong jet stream over the launch site. Orbital describes the upper level winds as "marginal," but the conditions will be monitored continuously with a series of weather balloons throughout the countdown.
A cold front pushed through coastal Virginia overnight, bringing showers and thunderstorms to the area. But the precipitation has ended and clouds are thinning out over the launch site, giving hope conditions will be favorable this evening for liftoff.
The countdown began with a call-to-stations for the Antares launch team. Over the next few hours, engineers will power up the 13-story rocket, load the launcher with refined RP-1 kerosene and liquid oxygen propellants, and activate the booster's systems for testing to ensure all is ready for flight.
The launch window has been shortened to two hours and now closes at 7 p.m. EDT (2300 GMT). The abbreviated launch window was planned going into the countdown and was conceived to ensure the launch team is not overworked and on console for too long, according to Orbital Sciences.
Once engineers begin loading super-cold liquid oxygen into the rocket's first stage, the available launch window will be condensed to 15 minutes. Orbital says the reason is to make sure the cryogenic oxidizer does not boil off too much during the countdown, a concern due to the limited supply of liquid oxygen available at the launch pad to replenish the rocket's tanks.
There is a 90 percent chance of favorable weather conditions during the launch window, according to NASA's Wallops Flight Facility.
The countdown will pick up at 9 a.m. EDT (1300 GMT), leading to the start of fueling about 90 minutes before liftoff.
The only slight concerns for Saturday are low and thick clouds and ground winds.
"Weather conditions deteriorate on Friday, April 19, but improve significantly over the next two days increasing the chances for acceptable conditions at launch time," Orbital Sciences said in a statement. "This also allows the Antares launch team a day of rest before back-to-back opportunities on Saturday, April 20 and Sunday, April 21."
Orbital Sciences officials received a weather briefing this afternoon, and the forecast continues to call for scattered thunderstorms and brisk winds associated with a cold front moving through coastal Virginia.
Engineers have identified the cause of the problem that caused the scrub of Wednesday's launch attempt.
"Flight controllers saw that an umbilical providing data, which connects the Transporter Erector Launcher (TEL) to the upper stage of the Antares rocket, became disconnected prior to the planned disconnect time," Orbital Sciences said in a statement. "The team determined the cause was a combination of slight hydraulic movement of the TEL and not enough slack left in the umbilical to allow for any additional or unplanned movement. Neither issue alone would have caused the umbilical disconnect, however, the combination resulted in the anomaly. Small adjustments are being made early today to both the hydraulics on the TEL and to the umbilical."
The umbilical provides a data link between the ground and the rocket's flight computer.
"he good news is that this is a simple adjustment to the external support systems," said Frank Culbertson, Orbital's executive vice president and mission director for the Antares test flight. "Given that this is a first run for the rocket and the first time use of a new launch facility, the fact that all systems were performing as planned while the team proceeded through the pre-launch checklists is very encouraging. It speaks volumes about the quality of the work done by this team and our partners."
The premature disconnect of the umbilical led to the scrub of yesterday's countdown to launch the Antares rocket on its first test flight.
But weather is a factor in the company's decision on when to try to launch again. The outlook for Friday calls for stormy weather and gusty winds violating criteria to launch the 13-story rocket from Wallops Island, a facility in coastal Virginia.
The Antares team will get a weather briefing at 4 p.m. EDT (2000 GMT) and make a decision on whether to try to launch Friday shortly thereafter, according to Orbital Sciences.
Engineers will have to troubleshoot the umbilical before proceeding with another try, and Orbital Sciences officials said Wednesday that Friday is the earliest the rocket would be ready for a second launch attempt.
The abort occurred after a smooth countdown with no major problems. Worries over an iffy weather forecast proved unfounded as sunny skies and light winds swept over the Antares launch site at NASA's Wallops Flight Facility on Virginia's Eastern Shore.
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Check out night photos of the Antares rocket on the launch pad and a selection of shots from the countdown.
The 48-hour turnaround was prompted by a scrub 12 minutes before the booster's scheduled liftoff today. A power umbilical connecting the rocket's second stage with the launch pad became disconnected, halting the countdown. Launch officials immediately ordered an abort and scrub.
The weather outlook for Friday is not great. The forecast calls for windy conditions and thunderstorms in the Wallops Island area.
Check out a timeline of key events during the launch.
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If you will be away from your computer but would like to receive occasional launch updates, sign up for our Twitter feed to get text message updates sent to your cellphone. U.S. readers can also sign up from their phone by texting "follow spaceflightnow" to 40404. (Standard text messaging charges apply.)
"Wallops has been here 68 years and launched some 16000 rockets," said Bill Wrobel, director of Wallops Flight Facility. "This one is, no doubt, by far, the largest thing to ever come off the island."
Orbital Sciences has launched more than 1,000 space missions, including satellites, missiles and its Pegasus, Taurus and Minotaur satellite launch vehicles. All its rockets so far have been solid-fueled.
"It's going to be the biggest, brightest and loudest thing that's ever launched form Wallops," said Frank Culbertson, executive vice president and general manager of Orbital's advanced systems group.
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.
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 3 minutes.
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.
The launch team has given the "go" for propellant loading to begin in a few minutes.
The start of fueling will restrict today's available launch window to 15 minutes. Officials are concerned an extended countdown would affect the temperature of the propellant.
The launch currently has a two-hour window extending until 7 p.m. EDT (2300 GMT).
Check out a map showing the visibility. And Orbital Sciences has posted a sampling of viewing opportunities at landmarks across the region.
High-pressure gaseous nitrogen will also be used to purge the Antares propellant tanks before fueling.
In the next few minutes, the launch team will activate and test the flight termination system, which would be used to destroy the Antares launcher if something went wrong during launch.
And the launch team has given the "go" to initiate the Antares fueling sequencer, which oversees preparations to fill the rocket with liquid propellant this afternoon. The team is also "go" to power on the Antares launch vehicle coming up at about 12 p.m. EDT (1600 GMT).
On Wednesday, those same engines - designed and constructed under the umbrella of totalitarianism in the former Soviet Union - will launch a commercial rocket conceived for a money-making mission.
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You can follow the countdown with this timeline.
The eight-hour countdown is beginning now with a call-to-stations for the Antares launch team. Over the next few hours, engineers will power up the 13-story rocket, load the launcher with refined RP-1 kerosene and liquid oxygen propellants, and activate the booster's systems for testing to ensure all is ready for flight.
The launch window has been shortened to two hours and now closes at 7 p.m. EDT (2300 GMT). The abbreviated launch window was planned going into the countdown and was conceived to ensure the launch team is not overworked and on console for too long, according to Orbital Sciences.
Once engineers begin loading super-cold liquid oxygen into the rocket's first stage, the available launch window will be condensed to 15 minutes. Orbital says the reason is to make sure the cryogenic oxidizer does not boil off too much during the countdown, a concern due to the limited supply of liquid oxygen available at the launch pad to replenish the rocket's tanks.
Orbital Sciences says technicians completed closeouts of final arming of the Antares rocket last night at about 9 p.m. EDT.
The weather continues to look iffy for today's launch, with less than a 50 percent chance of acceptable conditions during the launch window.
The 13-story rocket will take off in a three-hour window opening at 5 p.m. EDT (2100 GMT), rising from a new seaside launch pad on a 10-minute flight into Earth orbit.
It will be the first launch in a public-private partnership between NASA and Orbital Sciences, in which NASA is investing $288 million to help the Virginia-based company develop the Antares launcher and a resupply craft named Cygnus to service the space station.
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And check out photos of the Antares rocket on the launch pad earlier today.
The director of NASA's Wallops Flight Facility, Bill Wrobel, granted "Authority to Proceed" earlier today.
"ATP verifies the project managers, the Wallops range and range safety are ready to support the established plans and procedures for launch operations," NASA said in a statement.
Orbital Sciences Corp., operator of the commercial Antares launcher, gave a "go" to proceed toward liftoff during a readiness review yesterday.
The rocket is poised on the launch pad at the Mid-Atlantic Regional Spaceport at Wallops Island, Va. Liftoff is set for a three-hour window beginning at 5 p.m. EDT (2100 GMT).
Orbital Sciences Corp. officials held a Launch Readiness Review on Monday afternoon, giving a "go" to continue flight preparations. A meeting of Wallops range officials Tuesday will give the launch site's authority to proceed with the mission.
The weather outlook is iffy fror Wednesday, with a 45 percent chance of favorable conditions at the time of launch. Low clouds are the primary concern, according to NASA.
Back-up launch opportunities are available April 18-21.
The problem was uncovered during a countdown dress rehearsal Saturday at the Wallops Island launch pad in Virginia.
"Late in the countdown, at about T-16 minutes, the test was halted because the launch team had detected a technical anomaly in the process. Orbital has determined that a secondary pyro valve aboard one of the two first-stage engines used in the propellant chilldown process was not functioning properly," the company said in a statement.
Orbital said a replacement unit will be installed within 24 hours "with the goal of maintaining the April 17 launch date."
Wednesday's liftoff is scheduled during a three-hour window opening at 5:00 p.m. EDT (2100 GMT).
The "wet rehearsal" will exercise the launch team, the launch pad and the Antares rocket to mimic the conditions they will face Wednesday, the target launch date for the first flight of the commercial booster.
Orbital Sciences Corp. rolled the 133-foot rocket to launch pad 0A at the Mid-Atlantic Regional Spaceport on April 6.
Liftoff is set for a three-hour launch window Wednesday opening at 5 p.m. EDT (2100 GMT).
After a day to rest and review data, managers will convene a Launch Readiness Review on Monday to give final approval to proceed with flight preparations and launch day activities.
The long-range weather forecast calls for partly sunny weather on launch day.
The white two-stage rocket, emblazoned with an American flag on its nose, left its integration hangar before dawn riding horizontally on a specially-designed transporter. After pausing at the base of the launch pad, a hydraulic erector lifted the 133-foot Antares booster vertical at about 1 p.m. EDT (1700 GMT).
Now positioned on launch pad 0A at the Mid-Atlantic Regional Spaceport, the Antares rocket is set to undergo final testing and countdown exercises ahead of a test launch scheduled for April 17 at 5 p.m. EDT (2100 GMT), the opening of a three-hour window.
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Check out photos of the rollout.
The predawn rollout began around 5 a.m. EDT (0900 GMT), moving the rocket about one mile from the horizontal integration facility to the base of launch pad 0A at the Mid-Atlantic Regional Spaceport. Plans called for the two-stage booster to be lifted vertical on the pad later today.
The event occurred inside the Antares horizontal integration facility at NASA's Wallops Flight Facility in Virginia, where the rocket's stages and payloads are mated together before moving to the launch pad.
The rollout is scheduled to begin at 4:45 a.m. EDT (0845 GMT). The transporter, erector, launcher system, also known as the TEL, will lift the rocket upright on launch pad 0A by late morning.
Launch is planned in a window from April 17 to April 19. Orbital Sciences says it will narrow the launch period once the rocket is on the launch pad.
The commercial launcher will begin the one-mile journey from its horizontal integration facility to launch pad 0A at about 4:45 a.m. EDT (0845 GMT) Saturday, Orbital Sciences posted in an update on its website.
By late morning, the 133-foot-tall booster will be raised vertical on the launch pad at the Mid-Atlantic Regional Spaceport at Wallops Island, Va., Orbital Sciences said.
Engineers will connect the Antares rocket the launch pad ahead of a couple of weeks of preflight checks, countdown rehearsals and testing. The launch period for the test launch extends from April 17 to April 19.
The launch window each day opens at about 3 p.m. EDT (1900 GMT) and extends several hours.
Powered by a kerosene-fueled first stage and a solid-propelled upper stage, the Antares rocket's demo flight will verify the booster's performance before it begins launching robotic cargo ships to resupply the International Space Station.
NASA is paying Orbital Sciences up to $288 million to develop and demonstrate the Antares rocket and the Cygnus logistics spacecraft, which will be tested on the second flight of the Antares launcher this summer.
Orbital Sciences Corp., operator of the two-stage Antares launcher, announced the target launch date Friday, officially aiming for a three-day period from April 16 to April 18.
The launch time will be 3 p.m. EDT (1900 GMT) from the Mid-Atlantic Regional Spaceport, a facility owned by the governments of Virginia and Maryland. The spaceport lies on the property of NASA's Wallops Flight Facility on Virginia's Eastern Shore.
The launch is a demonstration mission for Orbital Sciences, which designed the Antares booster to launch supplies to the International Space Station.
Orbital has a $1.9 billion contract with NASA for eight cargo deliveries to the complex with the Antares rocket and the Cygnus resupply freighter.
The 133-foot-tall rocket will launch southeast from Wallops with an instrumented dummy payload mimicking the mass characteristics of the Cygnus spacecraft.
Powered by a dual-engine first stage and a solid-fueled second stage, the Antares rocket will reach orbit in about 8 minutes.
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The hot fire is a major milestone in the development of the Antares rocket. The test is designed to demonstrate the rocket's ignition system, launch pad infrastructure, and the dual-engine configuration of the launcher's first stage.
The first stage's twin AJ26 engines will ignite some time between 6 p.m. and 9 p.m. EST (2300-0200 GMT) at launch pad 0A at the Mid-Atlantic Regional Spaceport at Wallops Island, Va.
The first hot fire attempt Feb. 13 was aborted at T-minus 1.5 seconds after computers detected low pressurization levels of a nitrogen purge in the rocket's aft engine compartment.
Barry Beneski, a spokesperson for Dulles, Va.-based Orbital Sciences, said workers replaced a faulty valve on the launch pad to resolve the problem.
All systems are go for the hot fire tonight, and preparations are on schedule, Beneski said.
The Antares first stage has been on the launch pad since October undergoing a series of fueling tests and fit checks. Today's hot fire is the last major step before Orbital rolls out the first full-up Antares rocket for liftoff as soon as early April.
"After a preliminary overnight review of the data from the hot fire test attempt on February 13, Orbital's Antares team has identified low pressurization levels of a 'nitrogen purge' of the aft engine compartment as the reason the Antares flight computer, acting as designed, aborted the test with about 1.5 seconds left in the countdown," the Dulles, Va.-based company said in a statement.
The company said all other systems functioned normally, both on the Antares first stage and the launch pad at the Mid-Atlantic Regional Spaceport at Wallops Island, Va.
"Based on a preliminary assessment on the cause of the scrub, it looks like the turnaround work to prepare for another test will be fairly straightforward," said David Thompson, Orbital's chairman and CEO, in a quarterly conference call Thursday with investment analysts. "I'm hopeful that we'll be ready for another try within a week."
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"The planned first stage propulsion system 'hot fire' test of Orbital's new Antares medium-class rocket was halted in the final seconds of the countdown by the rocket's flight computer, which detected an anomalous condition. The Antares team will evaluate the data from the test to determine the nature of the abort. A new date for the test has not been determined."
"The test hot fire test is being conducted at Pad 0A at the Mid-Atlantic Regional Spaceport (MARS) at NASA's Wallops Flight Facility on the eastern shore of Virginia. The major objectives of the hot fire test are to verify the that pad's fueling systems and the Antares stage one test article functioned properly in a fully operational environment, that engine ignition and shut down commands operated as designed, and that the dual AJ26 first stage engines performed to specifications in the twin-engine configuration."
"#Antares hot fire halted in the final seconds of the countdown by flight computer. Team to analyze data and reschedule," the company's tweet said.
Unlike launches, there is no webcast or any real-time insight into the test.
NASA and Orbital Sciences officials are not providing updates on status of the hotfire, which is a major test before the first demonstration launch of Antares as soon as next month.
The engines will fire for 29 seconds while the Antares first stage is restrained on the launch pad at the Mid-Atlantic Regional Spaceport at NASA's Wallops Flight Facility in Virginia.
Officials plan to release an update following the test this evening.
The 29-second hotfire of the rocket's two AJ26 engines is expected between 6 p.m. and 9 p.m. EST (2300 GMT to 0100 GMT), according to a spokesperson for NASA's Wallops Flight Facility.
The engine test is a major step in Orbital's Antares rocket program, which aims to help haul cargo to the International Space Station beginning later this year.
Ignition of the rocket's two AJ26 engines is scheduled some time between 6 p.m. and 9 p.m. EST (2300 to 0100 GMT) Tuesday, according to a statement issued Friday by NASA's Wallops Flight Facility.
The Antares launch team, stationed in a control center on the mainland a few miles away, will oversee fueling of the rocket's first stage with kerosene and liquid oxygen propellants Tuesday afternoon and evening.
Held to the launch pad by restraints, the rocket's first stage will fire for 29 seconds, ramping up to 680,000 pounds of thrust. NASA says test will likely be visible and audible throughout the Wallops area.
The Antares rocket's AJ26 engines are provided by Aerojet, but the engines were built in Russia in the 1960s and 1970s for the Soviet Union's ill-fated N1 moon rocket. Aerojet imported the engines, called the NK-33 in Russia, in the 1990s and converted them to AJ26 engines by removing some harnessing, adding U.S. electronics, qualifying the engines for U.S. propellants, and modifying the engines to gimbal for steering.
Officials with NASA and Orbital Sciences said there will be no live webcast of the hotfire, but they plan to issue a statement and release imagery after the test.
"There is a bunch of data to look before we can say if it was successful," said Barry Beneski, an Orbital spokesperson.
NASA's Wallops Flight Facility will provide range support for the hotfire, including communications, data collection, range safety and area clearance, the base said in a statement.
Orbital Sciences moved the Antares first stage, designed by Yuzhnoye and built by Yuzhmash in Ukraine, to the launch pad in October after a series of problems with the facility's propellant handling systems forced a delay of more than one year.
Orbital blamed the issues on the Mid-Atlantic Regional Spaceport, or MARS, an organization formed by the governments of Virginia and Maryland to lure launch business to Wallops. MARS owns the Antares launch pad 0A, which lies on the property of Wallops Flight Facility on Virginia's Eastern Shore.
Engineers completed "cold flow" tests in January to test the pumps, plumbing, tanks and other systems responsible for filling the rocket with liquid propellant. The Antares rocket is the first Orbital launch vehicle to use large quantities of liquid propellant.
The two-stage rocket was developed by Orbital in a public-private partnership with NASA, which is providing the Dulles, Va.-based company with up to $288 million to design, build and test the Antares launcher and the Cygnus cargo craft, which will fly to the space station.
The first Antares launch, scheduled about one month after the hotfire, will not carry an operational payload. Orbital's technicians will remove the Antares first stage from the launch pad following the hotfire and roll a full-up Antares rocket out to the pad before the demonstration launch, which could occur as soon as March.
The first Cygnus spacecraft will fly on the second launch of Antares this summer on a demonstration mission to the space station.
Orbital Sciences has a $1.9 billion contract with NASA for at least eight operational resupply flights to the space station. The first such operational Antares and Cygnus mission is scheduled for the second half of 2013.