US company SpaceX on Tuesday became the first commercial outfit to send its own spacecraft toward the International Station with the launch of the cargo-bearing Dragon capsule.
"Three, two, one and launch of the SpaceX Falcon 9 rocket, as Nasa turns to the private sector to resupply the International Space Station," said Nasa commentator George Diller, as the spacecraft blasted off at 3:44 am (0744 GMT).
The test flight - which should include a fly-by and berthing with the station in the coming days - aims to show that private industry can restore US access to the ISS after Nasa retired its space shuttle fleet last year.
No humans are travelling aboard the Dragon, but six astronauts are already at the $100-billion space lab to help the capsule latch on, to unload supplies and then restock the capsule with cargo to take back to Earth.
The mission was delayed on Saturday due to a faulty engine valve in the rocket's main engine, but it was repaired the same day.
California-based SpaceX, owned by billionaire Internet entrepreneur Elon Musk, is the first of several US competitors to try sending spacecraft to the ISS with the goal of restoring US access to space for human travelers by 2015.
The company successfully test-launched its Falcon 9 rocket in June 2010, then made history with its Dragon launch in December of that year, becoming the first commercial outfit to send a spacecraft into orbit and back.
Its reusable Dragon capsule has been built to carry both cargo and up to seven crew members.
Until now, only the space agencies of Russia, Japan and Europe have been able to send supply ships to the ISS.
The three-decade US shuttle programme, which ferried astronauts and cargo to the research outpost, ended for good in 2011, leaving Russia as the sole taxi to the ISS until private industry comes up with a replacement.