WASHINGTON, May 24: SpaceX’s Dragon capsule on Thursday successfully completed a fly-under of the International Space Station, a key milestone in its groundbreaking test flight for private enterprise, NASA said.

Next, the unmanned spacecraft owned by Internet entrepreneur Elon Musk will attempt to latch onto the station on Friday to unload the half ton of supplies it has brought to space and then get restocked with gear to return to Earth.

“Everything held up under the scrutiny of really flying in space with Dragon for the first time,” said NASA flight director Holly Ridings of the fly-under that took the Dragon 2.5 kilometres from the $100 billion lab.

“To get through this piece of it obviously makes you feel positive, but in terms of the activities tomorrow there are still a lot of really new things that the teams need to perform and the vehicles frankly need to perform.”

Astronauts aboard the ISS are planning to help the berthing operation by reaching out with the station's robotic arm to grab the spacecraft so it can latch on to the Harmony module of the station.

If NASA gives the final go-ahead, the robotic arm grab attempt would begin around 8am with the docking itself scheduled for around 11.30am, Ridings told reporters.

On Thursday, the Dragon completed several manoeuvres to lay the groundwork for the berthing attempt, including an abort demonstration, communications tests and navigation on GPS (global positioning system) technology alone.

There was also a “free-drift demonstration,” whereby the capsule's thrusters were all shut down as it will need to do prior to being grappled by the space station's robotic arm, said lead mission director John Couluris of SpaceX.—AFP