Orbital Sciences' Cygnus spacecraft completed a successful rendezvous with the International Space Station (ISS) on Sunday, marking what NASA hailed as an "historical milestone" in commercial spaceflight. As the Wall Street Journal reports, the Cygnus unmanned vehicle linked up with the ISS Sunday morning, after an eleven day journey through space. Astronauts used a robotic arm to capture and secure the Cygnus, which will unload 1,300 pounds of supplies before departing (and self-destructing) within the next several weeks. With today's successful operation, Orbital becomes the second private company to send a spacecraft to the ISS, joining Elon Musk's SpaceX.

NASA has become increasingly reliant upon private sector initiatives in recent years, as the government phases out the shuttle program. The agency invested $285 million in research and development leading up to Sunday's launch (Orbital spent $500 million) and has committed to spending $1.9 billion on future Orbital projects over the next several years.

"Orbital joins SpaceX in fulfilling the promise of American innovation to maintain America's leadership in space," NASA Administrator Charles Bolden said in a statement. "As commercial partners demonstrate their new systems for reaching the Station, we at NASA continue to focus on the technologies to reach an asteroid and Mars."

Measuring 17 feet in length, the Cygnus capsule was scheduled to rendezvous with the ISS on September 22nd, but a software problem delayed its connection. It took off on Orbital's Antares rocket on September 18th, and approached within 40 feet of the ISS before the station's astronauts reeled it in. The craft will disconnect from the ISS on October 22nd, and will burn up as it descends into the atmosphere.

Today's successful link-up demonstrates Cygnus' ability to communicate and safely link up with the ISS, as Orbital looks to keep pace with SpaceX, its principal rival. Incidentally, SpaceX launched its next-generation Falcon 9 rocket later on Sunday, taking off from Vandenberg Air Force Station in California at 12 PM EDT. The upgraded Falcon 9 features longer fuel tanks and redesigned engines, and is carrying a space weather satellite from the Canadian Space Agency.