Spaceflight Insider

Orbital ATK obtains 2nd ULA Atlas V for Cygnus mission to ISS

The Pressurized Cargo Module (PCM) for the first Atlas V flight of Cygnus was recently delivered to NASA's Kennedy Space Center in Florida. Photo Credit: Orbital ATK

The Pressurized Cargo Module (PCM) for the first Atlas V flight of Cygnus was recently delivered to NASA’s Kennedy Space Center in Florida. Photo Credit: Orbital ATK

Under the $1.9 billion Commercial Resupply Services (CRS) contract that it has with NASA, Orbital ATK has made progress toward returning the aerospace firm’s Antares booster to flight. This is being achieved through the integration of the Russian-made RD-181 rocket engines into a new version of Antares – the Antares 200. However, to ensure it can meet the CRS timetable, it has also procured the use of a second United Launch Alliance (ULA) Atlas V 401 booster for a planned 2016 flight.

United Launch Alliance Atlas V 401 rocket Cape Canaveral Air Force Station Space Launch Complex 41 NASA MMS mission photo credit Michael Howard SpaceFlight Insider

As the ULA Atlas V carries out missions to the ISS, Orbital ATK are upgrading their Antares booster to return to service. Photo Credit: Michael Howard / SpaceFlight Insider

“Our reliable Atlas V offers the performance needed for our customer’s Cygnus spacecraft to carry the maximum cargo load to service the space station – 3,500 kg (7,716 lbs) of pressurized cargo,” said ULA president and CEO, Tory Bruno about this recent announcement.

With these two distinct, yet related efforts, Orbital ATK is hoping to maintain its agreement, all the while returning Antares to service – as early as the spring of 2016.

“We committed to NASA that we would resume CRS cargo delivery missions as soon as possible under a comprehensive ‘go-forward’ plan after the Antares launch failure last October,” said Orbital ATK’s President and Chief Executive Officer David W. Thompson. “Since that time, our team has been sharply focused on fulfilling that commitment. With a Cygnus mission slated for later this year and at least three additional missions to the Space Station planned in 2016, we are on track to meet our CRS cargo requirements for NASA.”

On October 28, 2014, an Antares rocket with it Cygnus spacecraft lifted off from the Mid-Atlantic Regional Spaceport’s (MARS) Pad-0A, located at Wallops Island in Virginia. Twelve seconds into flight, the booster exploded with the likely cause being a problem with a turbopump in one of the two AJ26 rocket engines in its first stage.

Orbital ATK had already been planning on moving away from the AJ26 at the time of the accident. The company has selected the RD-181, produced by the Russian firm NPO Energomash, as the replacement for the AJ26.

There will be two RD-181s engines within the first stage’s core structure. Orbital ATK is currently in the process of integrating and testing these engines into Antares.

A hot-fire test of the upgraded Antares is slated to take place at Pad-0A in early 2016. This test is being conducted to validate the booster’s operational performance and compatibility of the MARS launch complex with the redesigned launch vehicle. 

Once the certification and acceptance testing of the RD-181 had been completed, the first dual-engine ship-set was conducted – they arrived last month (July) at Orbital ATK’s Wallops Island facilities.

The two RD-181 rocket engines were integrated into the Antares 200 thrust frame adapter and modified first stage airframe. The airframe has been redesigned so as to accommodate the RD-181.

“The RD-181 engine provides extra thrust and higher specific impulse, significantly increasing the payload capacity of the Antares rocket.  This state-of-the-art propulsion system is a direct adaptation of the RD-191 engine, which completed an extensive qualification and certification program in 2013, accumulating more than 37,000 seconds of total run time,” said the President of Orbital ATK’s Flight Systems Group Scott Lehr.

New propellant lines, as well as Antares’ first stage avionics, are slated to arrive at Wallops toward the end of August in the lead up to full integration of the booster.

The RD-181 was installed into the into the Antares 200 thrust frame adapter and modified first stage airframe. Photo Credit: Orbital ATK

The RD-181 was installed into the into the Antares 200 thrust frame adapter and modified first stage airframe. Photo Credit: Orbital ATK

“With the delivery of the first set of flight engines now accomplished, and the second ship-set expected to arrive in the fall, Antares remains solidly on track to resume flights early in 2016.  In fact, within the next couple of weeks all the hardware for the next Antares vehicle will be at our Wallops final assembly facility, with equipment for several additional rockets following a few months later,” added Lehr. 

As Antares is being upgraded, the Cygnus spacecraft that will conduct the next mission, OA-4, is being readied for a flight atop a different rocket – United Launch Alliance’s Atlas V 401. If everything proceeds according to schedule, the Atlas V Cygnus flight should take place in December of this year.

Cygnus was designed to be flexible so that it can fly on different launch vehicles.

“For the OA-4 mission, launching aboard the more powerful Atlas V allows us to better support NASA’s ISS cargo needs with a full load of about 3,500 kg (7,716 lbs) of pressurized cargo, consisting of essential supplies, equipment and science experiments,” said the President of Orbital ATK’s Space Systems Group, Frank Culbertson.

According to Orbital ATK, the rationale behind the purchase of the second Atlas V was so that the company could provide NASA with “the maximum cargo load Cygnus can carry.” SpaceFlight Insider reached out to Orbital ATK on the matter and received the following response:

Working closely with NASA, it was decided that we would schedule another Cygnus mission on ULA’s Atlas V. The Atlas provides us greater delivery capacity to serve NASA’s needs, especially given the recent issues regarding ISS delivery. Antares remains on schedule to resume flight operations early spring 2016, supporting two to three missions that year.

Cygnus service module having its Ultraflex solar arrays installed. Photo Credit: Orbital ATK

Cygnus service module having its Ultraflex solar arrays installed. Photo Credit: Orbital ATK

Future CRS Cygnus spacecraft will incorporate an extended pressurized cargo module (PCM – the large, cylindrical section of Cygnus) which allows larger cargo payloads to be ferried to the International Space Station. These new Cygnus spacecraft will also employ lightweight Ultraflex solar arrays.

In preparation for the OA-4 flight, Cygnus’ PCM was delivered to Kennedy Space Center (KSC) earlier this week. It will now be integrated with the cargo vessel’s service module, slated to arrive at the space center in October.

Whereas the PCM is the cargo “trailer” for the vessel, the “cab” is its service module. Contained within are Cygnus’ avionics, electrical, and communications systems. At present, the OA-4 service module is in Dulles where Orbital ATK has its satellite manufacturing facility.

Once both components are at KSC, they will be assembled, fueled, and prepared to fly on the Atlas V. With 55 flights under its belt and a success rate of 100 percent, the selection of the Atlas V appears sound.

“In 2016, we will carry out at least three more CRS missions: two (or possibly three) will be launched by Antares rockets, the first of which is on a path to be ready to launch early in the year, and one more will be launched aboard Atlas V to support NASA’s need for additional cargo,” Culbertson said. “We have not finalized the exact sequence of these missions yet, but the plan capitalizes on the flexibility of Cygnus to launch on either vehicle and provides better schedule assurance for our customer.”


Jason Rhian spent several years honing his skills with internships at NASA, the National Space Society and other organizations. He has provided content for outlets such as: Aviation Week & Space Technology,, The Mars Society and Universe Today.

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