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After Antares test launch, Orbital aims for space station

Posted: April 26, 2013

Buoyed by a flawless test launch of the Antares rocket, the heavy-lifting part of its commercial cargo resupply system for the International Space Station, Orbital Sciences Corp. has its eye on a summer demonstration flight of the company's Cygnus resupply freighter.

Artist's concept of a Cygnus spacecraft awaiting grapple by the space station's robot arm. Credit: Orbital Sciences Corp.
The next flight, scheduled to launch in June or July, will go all the way to the space station and offers a steeper technical challenge for the Virginia-based aerospace contractor than the successful launch of its first Antares rocket Sunday.

"I'm not going to hold my breath any less on the next one than I did on this one," said Frank Culbertson, executive vice president and general manager of Orbital's advanced programs group. "Every launch is a challenge, and you want to make sure that it's all done right."

Sunday's flight was the culmination of a six-year, $300 million effort to design, build and test the Antares booster, which can loft medium-class satellites into orbit and is contracted by NASA to launch nine more times on cargo deliveries to the space station.

It also broke in a new $140 million launch pad at NASA's Wallops Flight Facility on Virginia's Eastern Shore. Launch pad 0A is owned by Mid-Atlantic Regional Spaceport and was mostly funded by the Virginia Commercial Space Flight Authority.

"Early results of the engineering analysis indicate that the vehicle's all-important first stage system, including its twin liquid rocket engines, performed exactly as expected, as did other vehicle systems as well as the launch complex's propellant and pressurization equipment," said David Thompson, Orbital's chairman, president and CEO.

Culbertson said the success of Antares permits the company to move on to the next phase of its $288 million agreement with NASA, which is how the U.S. government finances development of the Antares rocket and Cygnus spacecraft in partnership with Orbital's own capital.

"All of that demonstrated that when we do this again, we know how to make this happen and we'll get that payload - the Cygnus - into orbit and on its way to the International Space Station, so that it can continue its mission and we can provide the cargo, the experiments, the clothing and food that they need to sustain and extend their mission."

Already fueled and loaded with cargo, the first Cygnus spacecraft will be bolted to the second Antares rocket ahead of launch from Wallops Island, Va.

Sunday's Antares test flight only sent a dummy payload into orbit.

Workers loaded cargo into the Cygnus pressurized cargo module in March. Credit: Orbital Sciences Corp.
Engineers installed cargo bags into the spacecraft's cylindrical pressurized module, built by Thales Alenia Space of Italy, and pumped maneuvering propellant the vehicle's service module, manufactured by Orbital Sciences. The spacecraft will be kept in storage until it is ready for attachment to the Antares rocket at the launch base's horizontal integration facility, according to Culbertson.

"It's ready to be transferred into the horizontal integration facility, and as soon as the rocket is ready to receive it, we will integrate the two together and it will be ready to roll out to the pad some time this summer - probably late June or early July," Culbertson said. "So we will be on track for delivery, assuming the space station schedule can accommodate us, and we don't run into any unforeseen problems."

In March, technicians packed 1,235 pounds of cargo into the craft's Italian-built main cabin, then engineers mated the pressurized compartment to the Cygnus service module. Earlier this month, workers filled the spaceship's tanks with propellant.

"The spacecraft will not be the long pole in getting to the pad," Culbertson said. "It will be just evaluating the pad condition to see what we have to do to refurbish it, if anything, and then getting the next core completely assembled with its engines, the second stage, and get the fairing in here so we can assemble and attach the spacecraft to the front end, and then roll it out."

Workers will add some additional cargo, including fresh food, into the Cygnus spacecraft before it rolls to the launch pad.

The Cygnus freighter's cargo section is based on the multi-purpose logistics modules used by NASA to ferry supplies to and from the space station in the space shuttle era. Orbital devised the Cygnus service module using a design proven on the company's geostationary communications satellites.

While Orbital paid for the development of the Antares rocket with private financing, the company funded work on Cygnus jointly with NASA. Orbital started working on the Antares rocket in early 2007, and the firm won public funding from NASA in February 2008.

The assembled cargo and service modules of the first Cygnus spacecraft at NASA's Wallops Flight Facility. Credit: Orbital Sciences Corp.
NASA tapped Orbital and SpaceX, which has accomplished its space station test flights, for operational resupply missions to the space station in December 2008. Orbital's contract is worth $1.9 billion and covers eight flights through 2016.

The U.S. space agency turned to the commercial sector to replace some of the cargo-carrying capacity lost with the space shuttle's retirement.

Orbital's first four operational Cygnus missions will each carry up to 4,400 pounds of equipment, food and experiments to the space station. Orbital and Thales plan to introduce a larger cargo module for flights in the second half of the contract, raising the Cygnus capacity to nearly 6,000 pounds per flight.

Unlike SpaceX's Dragon spaceship, which can return hardware to Earth intact, the Cygnus will dispose of the space station's trash in a fiery re-entry back into the atmosphere, similar to most of the station's supply freighters.

One big advantage of the Cygnus is its ability to carry more volume than Dragon, according to NASA.

With most of the hardware for the next mission already at the Wallops launch base, engineers will complete pending safety reviews for NASA and space station partners to approve the approach of the Cygnus spacecraft within the outpost's vicinity.

"What's left to finish up is the verification of the final safety review packages to make sure it is compliant with the visiting vehicle requirements that we establish," said Alan Lindenmoyer, manager of NASA's Commercial Orbital Transportation Services program, which oversees the cost-sharing development agreement for the Orbital Sciences cargo resupply system.

"Once those verifications are complete, we'll go into a final review of flight readiness status," Lindenmoyer said.

Meanwhile, NASA and Orbital will continue joint testing of the Cygnus spacecraft's flight software.

"There has already been a great deal of joint testing done with the software simulating a mission, and that's gone very well," Lindenmoyer said.

The joint tests ensure the Cygnus software will function in concert with the space station.

"Software is always one of the most challenging things in any development," said Frank DeMauro, Orbital's Cygnus program manager.

Photo of the successful Antares test launch April 21. Credit: Orbital Sciences Corp./Thom Baur
Culbertson said the Antares and Cygnus teams will be ready when called upon.

"When we do this with a Cygnus spacecraft on the front end, and we have cargo to deliver, we're not going to have the luxury of a two-hour window," Culbertson said, referring to the length of the launch window on the Antares test flight. "We're going to have anywhere from five to zero minutes, so we're going to have to get it right the first time."

It will take three-to-five days for the Cygnus spacecraft to each the space station. The exact timing of the mission partially depends on finding an opening in the space station's busy manifest, which this summer includes the arrivals of European, Russian and Japanese resupply ships, plus a series of spacewalks.

"We'll be at a certain level of nervousness all the way to main engine cutoff and then to orbit insertion," Culbertson said. "But on that one, of course, we will have the additional challenge of making sure the Cygnus is actually in orbit and that it deploys its solar arrays, it has its own power, and then it can start its rendezvous maneuvers to get to the station, which will take about three-to-five days."

Along the way, controllers at Orbital Sciences headquarters in Dulles, Va., will put the Cygnus spacecraft through predefined tests, demos and health checks. NASA must sign off on the results of the tests before the craft can get close to the space station.

Using automatic on-board navigation aids, the Cygnus spacecraft will fly itself to a point about 30 feet below the space station, where it will be grasped with the lab's robotic arm and moved to a parking spot on the complex for a stay of up to a month.

"We won't relax for quite a while on that one until we're actually grappled, berthed to the station and the hatch is opened," Culbertson said. "Even then, we'll still want to make sure everything goes right, but that will be a major achievement."