A privately-owned cargo spacecraft has successfully reached the International Space Station, delivering a half-ton of supplies in its first official shipment for the U.S. space agency NASA.

Astronauts at the space station used a giant robotic arm to grab hold of the SpaceX company's Dragon capsule early Wednesday. Space station commander Sunita Williams announced to NASA's Mission Control in Houston that they had “tamed the dragon” when the capsule was secured.

The Dragon capsule is expected to stay at the International Space Station for about two and a half weeks.

California-based SpaceX is under a $1.6 billion contract with NASA that will require Dragon to make 11 additional supply shipments to the station. NASA is working with SpaceX to design capsules that can also carry astronauts.

NASA's second commercial supplier, Virginia-based Orbital Sciences Corporation, is scheduled to debut its Antares rocket and Cygnus spacecraft later this year.

The United States retired its shuttle fleet last year.