Nineteen months after suffering a spectacular explosion just seconds after liftoff, Orbital ATK is on the verge of returning their Antares rocket to flight at the Mid-Atlantic Regional Spaceport (MARS) this summer, located at NASA’s Wallops Flight Facility in Virginia. The loss of the ORB-3 mission in October 2014 was blamed on an engine turbopump employed by the rocket’s 40-year-old Soviet-era Russian NK-33 engines (refurbished by Aerojet Rocketdyne and redesignated as the AJ-26), and forced Orbital ATK to make changes to their rocket’s design.
Now, the new and improved version of the booster is at its launch pad sporting new RD-181 engines, which is the biggest change made to Antares after the original AJ-26 engines proved unreliable (Orbital ATK also had AJ-26 engines fail on a test stand, twice, the latest in May 2014).
The rocket was transported from the company’s Horizontal Integration Facility (HIF) to nearby Launch Pad-0A on May 12 and, according to Orbital ATK, will be put through a 30-second static hot-fire test on the launch pad in “the next few weeks.”
“The team will continue to work meticulously as they begin final integration and check outs on the pad and several readiness reviews prior to the test,” added the company in a statement May 12. “The window for the stage test will be over multiple days to ensure technical and weather conditions are acceptable.”
Currently targeting a “Return to Flight” launch date of July 6, the mission will follow the OA-6 mission launched from Florida last March, which was added to the manifest when Orbital ATK decided to purchase a second Atlas-V rocket from United Launch Alliance (ULA) to fly their Cygnus cargo ship to the ISS. Because preparations for OA-5 were already underway when the second Atlas-V launch was ordered, the mission numbers are out of sequence.
Orbital ATK originally planned to use the entire OA-5 vehicle for the hot-fire test before integrating their Cygnus cargo ship. Instead, a separate core stage is being used, which allows for processing of the OA-5 vehicle to proceed in parallel with the upcoming test fire.
The test stage now at Launch Pad-0A will later be refurbished and used to launch the 0A-7 mission, scheduled to fly no earlier than October 2016.
In addition to improved reliability over the former AJ-26 engines, the RD-181 will offer a performance boost for Antares. “The RD-181 has a little higher thrust, a little higher specific impulse, which results in about a 20-25% increase in our cargo capacity to CRS orbit.” said Mike Pinkston, Orbital ATK’s Antares Program Manager, during our visit to see the Antares 0A-5 and 0A-7 hardware a few months ago.
This, combined with the extra capacity of the enhanced Cygnus, will enable Orbital ATK to deliver up to 3200 kg of cargo to the ISS.
As outlined previously by AmericaSpace reporter Elliot Severn, repairs at the launch pad were completed on Sept. 30, 2015, along with upgrades to support the new Antares configuration. According to Dale Nash, Director of the Virginia Commercial Space Flight Authority: “We completed a performance test of all the new systems in the first week of November. We will continue to run the procedures, do the simulations, and make sure everyone is up to speed and in launch mode to support the hot fire and the return to flight and a pretty busy manifest after that.”
With the launch pad now flight ready, Nash and his team could support a launch with only a few weeks’ notice. Repairs have been made to the ablative material inside the flame trench after the first hot-fire in 2013 and five subsequent launches took their toll. Having a fresh layer of insulation will be essential for the upcoming hot-fire test.
“The hot fire usually causes more wear and tear because it sits here and dwells for more than 30 seconds.” said Nash. “On a normal launch, it’s no more than a few seconds before it goes away.” These repairs should sustain the pad for the hot-fire and four to five launches in rapid succession.
Meanwhile, the company’s Cygnus cargo ship service module for OA-5 arrived at Wallops this week for processing and integration into an extended pressurized cargo module for July’s Return to Flight. The service module holds all of the avionics, electrical, propulsion, and communications systems for the ship.
Together with SpaceX, Orbital ATK has contracts from NASA to provide resupply services to the ISS. Under the original $1.9 billion contract, signed in December 2008, Orbital Sciences Corp. was tasked with delivering 44,000 pounds (20,000 kg) of equipment and supplies on eight dedicated Cygnus missions, to be flown by 2016. Following an initial demonstration mission to the station in the fall of 2013, Orbital flew two of those dedicated missions in January and July 2014, before the loss of ORB-3 the following October.
In early 2015, Orbital merged with parts of Alliant Techsystems (ATK) to become “Orbital ATK” and in December returned the Cygnus to flight with the newly-renamed OA-4 mission. The remainder of the original eight flights remain on the books, although the recently-trialed Enhanced Cygnus—which benefits from a larger payload capacity than its predecessor, the Standard Cygnus—was expected to allow Orbital ATK to complete its original commitment to NASA in seven missions.
Last August, NASA awarded the company three more Enhanced Cygnuses through the end of 2018, which will loft a combined total of 59,000 pounds (26,800 kg) of equipment and supplies to the ISS. More recently, in January 2016, Orbital ATK was selected for the follow-on NASA CRS-2 contract, which will guarantee the company at least six more Enhanced Cygnus missions between 2019 and the currently timetabled end of ISS operations in December 2024.
Writers Elliot Severn and Ben Evens contributed to this report.
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