Astronauts aboard the International Space Station successfully grappled and berthed Orbital Sciences Corp's Cygnus "Orb-1" capsule early Sunday, marking the Dulles, Va. based company's first cargo delivery under the provisions of an eight-flight, $1.9 billion Commercial Resupply Services (CRS) agreement with NASA in effect through 2016.
U.S. and Japanese astronauts Mike Hopkins and Koichi Wakata, positioned at a control post in the station's cupola observation deck, captured the unpiloted, 10,000-pound spacecraft using the station's 58-foot-long Canadian-built robot arm at 6:08 a.m., EST, following a thre- day "stair step" series of rendezvous maneuvers that began with Thursday's lift off of the Antares/Cygnus rocket and cargo carrier from Virginia's Mid-Atlantic Regional Spaceport.
The commercial freighter, with its 2,780 pounds of provisions, science and experiment hardware, computer equipment and spacewalk tools, was maneuvered to a berthing with the station's U.S. segment Harmony module by the two robot arm operators and secured at 8:05 a.m., EST.
Orbital Science Corp's Cygnus, top, nears International Space Station for robot arm capture on Sunday. The Indian Ocean looms 260 miles below. Photo Credit: NASA
Access to the capsule by the ISS crew was planned for late Sunday or early Monday. In addition to a commercial fleet of 28 Earth-observing nanosats for Planet Labs of San Francisco, some of the science delivery includes an assortment of 23 student experiments, among them a live ant study, to encourage youthful interest in the science, technology, engineering and math fields. Other provisions included an assortment of fresh food and holiday gifts.
The capsule, named for the late NASA astronaut and test pilot C. Gordon Fullerton, will remain berthed to the station until Feb. 18. It will depart with trash for a destructive re-entry into the Earth's atmosphere.
Rendezvous and capture operations aboard the six-person orbiting science laboratory began Sunday, shortly after 1 a.m., EST, as Cygnus began a series of precise close in rendezvous maneuvers coordinated by NASA's Mission Control in Houston, Orbital's flight control center in Dulles and the Japan Aerospace Exploration Agency in Tsukuba.
"The snares are open, and we have a great view of the vehicle," Hopkins reported, with the freighter just over 1,000 meters from the ISS, shortly after 4 a.m., EST. The "snares" are the internal grapple mechanism within the tip of the robot arm.
The capsule closed to a separation of 250 meters, a critical "go-no go" point in the rendezvous activities by 5 a.m., EST, well ahead of schedule. Orb-1 began its advance again at 5:17 a.m., and shortly afterwards Hopkins and Wakata performed a successful check of their ability to remotely control the spacecraft, including the issuance of an abort command if necessary to avoid a collision. Cygnus reached 30 meters separation, a hold point, at 5:44 a.m., EST, and then closed to the capture point at 10 meters below the station.
Originally scheduled for a December lift off, the Orb-1 mission was delayed by a Dec. 11, ISS thermal control system flow control valve failure that prompted a pair of contingency pre-Christmas spacewalks by Hopkins and NASA's Rick Mastracchio; a January blast of cold weather at the Wallops Island launch site; and concerns over the radiation environment in Earth orbit from high solar activity last week as the Antares launch vehicle awaited lift off.
"You've got to stay flexible, persistent and pay attention to details," noted Frank Culbertson, Orbital's executive vice president and general manager of advanced programs.
Orbital joined SpaceX, of Hawthorne, Calif., as an approved ISS U.S. commercial re-supply service last September-October, as the Dulles firm completed an ISS demonstration mission flown under NASA's Commercial Orbital Transportation Services program.
Orb-1 marks the first of eight multi-national ISS cargo missions anticipated in 2014. Orbital Sciences is preparing additional missions of its own in early May and late October. Those are to set the stage for the inaugural launch of a Cygnus upgrade, which will increase the cargo carrying capability of the freighter by an estimated 600 to 700 kilograms, or 1,300 to 1,600 pounds. The debut is anticipated by mid-2015.
Russia's Progress 54 cargo mission is tentatively set for a Feb. 5 lift off. SpaceX is to follow on Feb. 22 with the launch of its third CRS flight.