Space Station Schedule May Delay Antares Return to Flight

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PASADENA, Calif. — While Orbital ATK says it is on schedule to have the new version of its Antares launch vehicle ready for flight in March, the vehicle’s first launch may be delayed by other missions to the International Space Station, including a Cygnus cargo spacecraft launching on an Atlas 5.

“Our initial launch capability for the re-engined Antares is scheduled for March of 2016,” said Mark Pieczynski, vice president of strategy and business development for Orbital ATK’s Flight Systems Group, in a panel session at the American Institute of Aeronautics and Astronautics’ Space 2015 conference here Sept. 1.

Pieczynski said work replacing the AJ-26 engines previously used on the first stage of the Antares with RD-181 engines was on schedule. That effort, he said, includes a static fire test of the vehicle on the pad at the Mid-Atlantic Regional Spaceport in Virginia planned for January.

While the vehicle may be ready for flight in March, it may have to wait for its payload. Orbital announced Aug. 12 it would launch a second Cygnus cargo mission on a United Launch Alliance Atlas 5 in 2016, after a previously announced launch scheduled for December. Orbital and ULA officials said here that second launch is planned for March.

If that schedule holds, the Antares launch would likely be delayed. “We will be ready for launch in March, but we may not launch in March,” said Warren Frick, advanced projects program manager at Orbital ATK, in a separate presentation at the conference Sept. 1. “We will work whatever is most effective for the program.”

One advantage to flying Cygnus on an Atlas 5 is the increased cargo that the spacecraft can carry to the ISS. “Those launches are actually twice the capacity of the other commercial cargo launches that have happened,” said Dan Collins, ULA’s chief operating officer. “So we’re … basically going to get four launches from here to next spring” on those two Atlas 5 Cygnus launches.

The re-engined Antares, while not as powerful as the Atlas 5, will offer increased performance over the earlier version of the Antares. The RD-181 engines provide higher thrust and greater efficiency than the AJ-26 engines, Frick said, increasing the vehicle’s payload for ISS missions from 5,800 to 7,000 kilograms.

Although the engine is more powerful, Frick said Orbital was able to use it on Antares with minimal changes to the overall rocket, primarily in the way the engines are attached to the core structure of the vehicle. “We did not really make any changes to the core,” he said. “We just changed how we attach the engines to the core.”

He added that Orbital ATK is looking at future modifications to the rocket to optimize it for the RD-181 engines. Those changes would increase the vehicle’s payload capacity for ISS missions by an additional 1,000 kilograms.

Plans for replacing the first stage engines in Antares were already in progress at the time of the October 2014 launch failure, blamed on the failure of a turbopump in one of the rocket’s AJ-26 engines. “We had always planned on re-engining it,” Frick said, both to increase performance and because of the limited supply of AJ-26 engines available. “At the time of the failure we had already selected the new engine. It just sped up how fast things went.”

The final report of the investigation into that failure is complete and has been delivered to the Federal Aviation Administration, Frick said, but declined to discuss its contents. He did note in one chart that none of the current suppliers for the Antares vehicle “has any implications in the failure.” That list of suppliers no longer includes Aerojet Rocketdyne, which provided the AJ-26 engine.

While the RD-181 provides improved performance for the vehicle, Pieczynski suggested the company has longer-term plans for the Antares. Asked about using the Russian-built engine on Antares, he said the company had no other options for the vehicle. “We needed a quick solution, and the fact of the matter is that there are no quick solutions in propulsion technology in the United States today,” he said.

“We see that as probably a mid-term solution to a longer-term solution,” he said of the RD-181.