Orbital Sciences' Cygnus commercial craft departed from the International Space Station (ISS) Tuesday morning after spending three weeks at the International Space Station.

Flight Engineers Luca Parmitano and Karen Nyberg oversaw the process of removing the disposable spacecraft from the ISS's Harmony node before releasing it into space.

Come Wednesday, Cygnus will fire its engine one last time as it re-enters the Earth's atmosphere in a dramatic, fiery ending over the Pacific Ocean.

By successfully delivering 1,300 pounds of supplies, Orbital became the second private company after SpaceX to rendezvous with the orbiting lab.

The mission represented a test run for Orbital, which has contracted $1.9 billion with NASA to conduct eight space station resupply missions. The test mission hit a snag when a technical glitch interrupted Cygnus' approach sequence as it neared the ISS in late September, delaying its berthing as the company worked through the problem.

Despite this, the mission has thus far been considered a success, with Orbital set to carry out its first official commercial resupply mission in December.

According to NASA, Cygnus will help ensure the space agency's ability to carry out future missions.

"Future Cygnus flights will ensure a robust national capability to deliver critical science research to orbit, significantly increasing NASA's ability to conduct new science investigations to the only laboratory in microgravity," it said in a statement.

Both Orbital and SpaceX are a part of NASA's Commercial Orbital Transportation Services (COTS) program. Launched in 2008, COTS invests "financial and technical resources to stimulate efforts within the private sector to develop and demonstrate safe, reliable and cost effective space transportation capabilities."