SpaceX Dragon flies by space station

The first US commercial spacecraft to head for the International Space Station made its first fly-by of the orbiter this morning and now is undergoing a series of pre-rendezvous tests.

The unmanned Dragon cargo spacecraft, which launched Tuesday from Cape Canaveral Air Force Station in Florida, flew 2.5 kilometres under the space station this morning, NASA reported.

Just before 6:30 a.m. EDT today, space station astronauts spotted Dragon as it approached their point in orbit. As it neared the station, astronauts commanded the spacecraft to turn on its strobe light, successfully verifying that they can send commands and that Dragon will execute them.

"The @SpaceX #Dragon capsule fly-under of the #ISS has been successfully completed!" NASA tweeted this morning. The space agency also noted that all demonstration objectives for the day have been filled.

Video cameras onboard the space station captured images of Dragon during today's fly-by..

Now that the fly-by has been completed, scientists will focus on a series of system tests.

Dragon is scheduled to rendezvous and dock with the space station on Friday when a robotic arm will reach out, grab it and attach it to the outside of the station.

The cargo-bearing spacecraft was designed and built by Space Exploration Technologies Corp., also known as SpaceX.

NASA retired its fleet of space shuttles, which had been ferrying astronauts back and forth to the space station, last summer. The space agency is now relying on commercial ventures to serve as space taxis.

The launch of the SpaceX Dragon was historic because it was the first commercial flight from the U.S. to the space station.

"We're now back on the brink of a new future, a future that embraces the innovation the private sector brings to the table," NASA Administrator Charles Bolden said in a statement on Tuesday. "The significance of this day cannot be overstated."

The Dragon cargo capsule is carrying about 1,200 pounds of supplies for the station, along with student-designed experiments, according to NASA.

The space agency also noted that the spacecraft can hold 7,300 (3310kg) pounds of cargo, but since this is a test flight, cargo was limited to important-but-not critical materials. Most of the supplies sent on this trip are food and clothing.