A commercial Cygnus cargo craft completed a smooth laser-guided approach to the International Space Station on Wednesday, resupplying the 450-ton research complex and its six-person crew with food, experiments and other gear vital to keeping the orbiting laboratory operating.

The Cygnus spacecraft on approach Wednesday beneath the International Space Station. Photo credit: NASA/ESA/Alexander Gerst
 
Flying more than 250 miles above Earth, the Orbital Sciences Corp. supply spaceship deftly controlled its approach to the space station, firing rocket thrusters as required guide itself to an imaginary box about 30 feet below the outpost.

Space station commander Steve Swanson took control of the lab's 58-foot-long Canadian-built robotic arm to reach out and capture the Cygnus spacecraft at 6:36 a.m. EDT (1036 GMT).

"We now have a seventh crew member," Swanson said moments after snaring the Cygnus spacecraft with the robot arm. "Janice Voss is now part of Expedition 40."

Orbital Sciences christened the Cygnus as "Spaceship Janice Voss," naming it for the late astronaut and former Orbital employee.

"Janice devoted her life to space and accomplished many wonderful things at NASA and Orbital Sciences, including five shuttle missions," Swanson said. "And today Janice's legacy in space continues. Welcome aboard the ISS, Janice."

Ground controllers in Houston commanded the robot arm to maneuver the Cygnus spacecraft into position on the Harmony module's Earth-facing berthing port. A series of 16 bolts were driven into place to establish a firm mechanical connection between the Cygnus and the space station.

Astronauts were expected to open hatches between Harmony and the Cygnus spacecraft's Italian-built pressurized module as soon as Wednesday afternoon, beginning the transfer of 3,293 pounds of equipment and cargo bags into the space station.

The supplies include food for the lab's six-man crew, research experiments to learn how the human body changes in space, gear to maintain systems aboard the massive research complex, and 32 small CubeSats to be ejected from the space station's Japanese science module.

According to a cargo manifest provided by NASA, the spaceship delivered 1,684 pounds of crew supplies -- such as care packages, provisions and food -- 783 pounds of vehicle hardware and spare parts for the space station, and 721 pounds of science experiments.

Other items include a pump for the Japanese laboratory and a hardware kit to prepare for future spacewalks to install a new nitrogen and oxygen system outside the space station's airlock.

High-tech GPS and laser navigation systems guided the Cygnus on its rendezvous, which featured the debut of a new navigation sensor to aid the craft's approach to the space station.

The TriDAR sensor, developed and built by Ottawa-based Neptec Design Group, is a next-generation rendezvous aid tested on three space shuttle flights, including the final mission in July 2011.

The Cygnus spacecraft's previous laser navigation system measures the distance and closing rate of the spaceship by bouncing light signals off of reflectors mounted on the space station's Japanese lab module. The TriDAR system does not need reflectors, instead determining the Cygnus spacecraft's position by creating a three-dimensional thermal map of the station and comparing it with a model embedded in the system's software.

The TriDAR is also effective at greater distances from the space station, according to Neptec engineers.

The mission -- named Orb-2 -- is Orbital's second operational resupply run to the space station. The Dulles, Va.-based aerospace contractor conducted two test flights in 2013 before launching operational cargo service on the Orb-1 mission in January.

Orbital planned to use the TriDAR in backup mode on Orb-2. If it provided good data, officials said it will be used operationally on the Orb-3 resupply mission in October.

"Every flight is critical," said Frank Culbertson, executive vice president of Orbital's advanced programs group and a former space shuttle and space station commander. "We carry a variety of types of cargo on-board, which includes food and basic supplies for the crew, and also the research."

Astronauts Steve Swanson and Alexander Gerst inside the space station's cupola module, where they monitored the rendezvous of the Cygnus cargo craft and operated the robotic arm. Photo credit: NASA/ESA/Alexander Gerst
 
The Cygnus spacecraft launched Sunday on top of an Antares rocket from NASA's Wallops Flight Facility on Virginia's Eastern Shore.

Sunday's launch was delayed from early May after a bottleneck in the space station's busy manifest of visiting cargo and crew vehicles. Orbital announced further delays as engineers ensured the AJ26 powerplants on the Antares rocket were free of the defect that caused a major engine mishap on a test stand in Mississippi.

Orbital has a $1.9 billion contract with NASA to cover eight logistics missions through 2016. NASA has a similar contract with SpaceX, which takes up cargo with its Falcon 9 rocket and Dragon capsule, then returns experiment samples to Earth.

Both companies are contracted to haul 20 metric tons, or about 44,000 pounds, of cargo to the space station.

The U.S.-owned Cygnus and Dragon resupply vehicles, along with Russia's Progress, the European Space Agency's Automated Transfer Vehicle and Japan's H-2 Transfer Vehicle, make up the space station's life line with Earth to get critical hardware, life-support commodities, and food to the complex orbiting more than 250 miles up.

"They really can't afford to get behind on any of that with six people up there, and if we're going to keep six people on the station, we need a routine and regular delivery of cargo, and that's what we're trying to establish with this service," Culbertson said before Sunday's launch.

"You've got to resupply the crew, you've got to keep the research flowing up to them, and you've got to have reliable return of some of the research samples," said Dan Hartman, NASA's deputy space station program manager. "There's a lot of system maturation that we need to do that we're testing on the International Space Station if we're going to go deeper and farther into the solar system."

NASA views the space station as the cornerstone of the agency's long-term space exploration strategy. Officials say physiological research and technology demonstrations aboard the space station are critical to making human missions to an asteroid or Mars feasible.

"The way to succeed and buy down on all that risk is to have all these vehicles -- the Cygnus, the ATV, the HTV, the SpaceX [Dragon] -- and have a consistent resupply of not only the supplies needed for the crew, but also the cutting edge technology demonstrations that we need to fly to test -- and yes, fail at times and retest -- just to have that big learning experience as we go forward."

The Cygnus mission carried 32 CubeSats, including 28 shoe box-sized spacecraft for San Francisco-based Planet Labs Inc., which is in the middle of launching a fleet of 100 small satellites to observe the entire planet every 24 hours.

The satellites are part of the Planet Labs "Dove" constellation designed to collect images of Earth from orbit.

Another CubeSat built at NASA's Ames Research Center in California will test a new de-orbit system to induce drag on small objects in space, potentially leading to technologies that could enable scientists to return samples to Earth.

The CubeSats will be released by a deployment mechanism outside the space station's Japanese Kibo laboratory.

The Cygnus spacecraft will depart the space station around Aug. 15. Controllers will guide the cargo carrier to a destructive re-entry over the Pacific Ocean a few days later, disposing the space station's trash and other excess hardware.

"Our plan is to keep Cygnus on-board for about a month, stow it with disposable cargo, and then prepare ourselves for the next mission, which will be the ATV in late July," Hartman said.

The European ATV cargo vehicle is set for liftoff from French Guiana on an Ariane 5 rocket July 24, with docking planned Aug. 12.

A Russian Progress supply ship heading for the space station is also being readied for launch from Kazakhstan on July 23.

Follow Stephen Clark on Twitter: @StephenClark1.