CAPE CANAVERAL, Florida – A robotic Japanese cargo ship reached the International Space Station on Thursday, the first of a quartet of spaceships due to arrive at the orbital outpost over the next month.

The ship, laden with supplies, science equipment and spare parts, is the second from Japan to dock at the station.

Its arrival boosted confidence that supply lines to the $100 billion outpost, a project of 16 nations, will remain fully operational after NASA retires its space shuttle fleet in about six months.

Japan's HTV-2 spacecraft, Europe's Automated Transfer Vehicles and Russian Progress capsules will become the station's lifelines after two or three more space shuttle flights.

The shuttle program is ending after 30 years due to high operating costs and to free up funds to develop U.S. spaceships that can travel beyond the station's orbit 220 miles above Earth.

The U.S. space agency hopes commercial carriers Space Exploration Technologies and Orbital Sciences Corp will pick up some of the station's supply runs as early as December. Crew transport to the station already is exclusively provided by Russian Soyuz spacecraft, at a cost to the United States of $51 million per seat.

Japan's second HTV, named Kounotori, launched on Saturday aboard a Japanese H-2B rocket from Tanegashima Space Center in southern Japan.

The craft hovered about 33 feet from the station early on Thursday while station flight engineer Catherine "Cady" Coleman, working from inside the station's cupola compartment, maneuvered the station's robot arm into position to snare the 35,000-pound (15,875 kg) vessel. With Kounotori firmly in the crane's grasp, it was then attached to a berthing port on the station's Harmony node.

The six-member station crew, led by NASA astronaut Scott Kelly, will begin unloading Kounotori's 3.2 tons of spare parts, food, research equipment, computers, water and other supplies on Friday.

The next batch of cargo is right behind. A Russian Progress rocket was scheduled to lift off from the Baikonur Cosmodrome in Kazakhstan on Thursday and reach the station on Saturday.

The European Space Agency's second Automated Transfer Vehicle, or ATV, named Johannes Kepler, is slated for launch on February 15. NASA's space shuttle Discovery is due to launch on February 24 with spare parts and a storage room, among other items.