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Launch of next Antares rocket slips to July

Posted: June 10, 2014

An inquiry into a rocket engine failure during a May 22 ground test will keep the next Orbital Sciences Corp. cargo resupply flight to the International Space Station from launching until at least July 1, the company announced Monday.

File photo of an Antares rocket rolling to the launch pad in January at Wallops Flight Facility, Va. Photo credit: Orbital Sciences Corp.
Orbital officials said the launch of its fourth Antares rocket is set for no earlier than July 1, but the date depends on the conclusion of an investigation into a mishap that damaged an AJ26 rocket engine during a ground test at NASA's Stennis Space Center in Mississippi.

The engine failed approximately 30 seconds into a planned 54-second "acceptance test" at Stennis, during which engineers check the engine's readiness for flight. The AJ26 engine damaged during the May 22 test firing was supposed to fly on an Antares rocket in 2015.

The Antares rocket's first stage is powered by two AJ26-62 kerosene-fueled engines. The engines for the next launch have already passed acceptance testing and are mounted on the rocket for launch, but officials want to verify the engines are not susceptible to whatever caused the failure on the test stand in Mississippi.

Orbital's supplier for the AJ26 engines is Aerojet Rocketdyne, which purchased stockpiled 1970s-era NK-33 engines from Russia and modified them for use on U.S. rockets.

Julie Van Kleeck, Aerojet Rocketdyne's president of advanced space programs, said Friday that the company has a stockpile of NK-33 engines in the United States it could convert to the AJ26 configuration for Orbital if the engine damaged May 22 cannot be repaired.

Orbital Sciences purchased 20 AJ26 engines from Aerojet Rocketdyne for 10 Antares rocket launches. Orbital has a $1.9 billion contract for eight operational resupply flights to the space station, and the company flew two demonstration missions in 2013.

The next cargo mission is known as Orb-2. It's the second of the eight-flight contract awarded by NASA in December 2008.

"The investigation into the failure is being led by the Antares main stage propulsion supplier, Aerojet Rocketdyne, with Orbital and NASA engineers also supporting the effort," Orbital said in an update posted on its website. "Once the investigation team reaches the point in their process that they can clear Antares to launch the Orb-2 mission, a targeted launch date will be established. For now, [no earlier than] July 1 is simply a planning date."

The company's Cygnus automated cargo craft, which is already fueled and packed with supplies, will be stored inside a clean room at NASA's Wallops Flight Facility on Virginia's Eastern Shore until officials authorize the launch team to restart flight preparations.

Once processing resumes, technicians will transport the Cygnus spaceship to the Antares rocket's horizontal integration facility for attachment to the two-stage launch vehicle. Then ground crews will install last-minute experiments and fresh food into the supply craft's pressurized module before rolling out to the launch pad two or three days prior to liftoff.

Follow Stephen Clark on Twitter: @StephenClark1.