UPDATED July 16 at 9:54 a.m. EDT

WASHINGTON — A Cygnus space freighter operated by Orbital Sciences Corp. of Dulles, Virginia, was berthed with the international space station at 6:36 a.m. Eastern time July 16 as part of the company’s second paid cargo delivery mission for NASA.

The expendable Cygnus launched July 13 aboard Orbital’s Antares rocket from Pad 0A at the Mid-Atlantic Regional Spaceport, a Virginia-operated launchpad at NASA’s Wallops Flight Facility on Wallops Island, Virginia. It was the fourth successful launch for Antares, which Orbital developed with financial assistance from NASA.

Cygnus is delivering nearly 1,700 kilograms of cargo and will spend about 30 days berthed with space station’s Harmony node. Once Cygnus’ cargo has been unloaded, station crew members will load the barrel-shaped freighter with some 1,300 kilograms of trash, which will be destroyed along with Cygnus in a planned destructive re-entry.

When the disposal leg of the mission is complete, the second of eight flights Orbital owes NASA under a $1.9 billion Commercial Resupply Services contract signed in 2008 will be in the books. The company is on the hook to deliver at least 20,000 kilograms of cargo by the end of 2017. It has delivered 3,129 kilograms of cargo so far over two missions, according data posted on Orbital’s website. The first of these missions launched in January. 

Antares and Cygnus were supposed to launch in May, but the mission was held up after a rocket engine intended to power one of Orbital’s 2015 cargo missions failed on the test stand at NASA’s Stennis Space Center in Mississippi. After the failures, Orbital held up its second cargo mission to investigate the engines that had been integrated with the rocket that launched July 13. The engines eventually checked out, and the mission was cleared to launch July 11, only to be delayed two days by bad weather on Virginia’s Eastern Shore.

The core stage of each Antares rocket uses two AJ-26 engines: converted NK-33 engines made by Russia’s Kuznetsov Design Bureau for a failed Soviet Moon program. Aerojet Rocketdyne of Sacramento, California, refurbishes and rebrands these engines and resells them to Orbital.

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Correction: An earlier version of this story said Orbital Sciences is on the hook to deliver at least 20,000 kilograms of cargo by the end of 2015.

Dan Leone is the NASA reporter for SpaceNews, where he also covers other civilian-run U.S. government space programs and a growing number of entrepreneurial space companies. He joined SpaceNews in 2011.Dan earned a bachelor's degree in public communications...