CAPE CANAVERAL, FL—There’s still no official launch date set, but upstart SpaceX took one more step towards becoming the first commercial company to deliver supplies to the International Space Station (ISS) by completing a “Wet Dress Rehearsal” of their Falcon 9 Rocket Thursday.

At Launch Complex 40 the fully assembled two stage rocket and attached Dragon spacecraft were rolled out to the launch pad and placed into launch position. The rocket was then fully loaded with RP1 kerosene and Liquid Oxygen rocket fuel, the same fuels used to power the first stage of the famous Saturn V launch vehicle that sent astronauts to the moon.

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The launch team then proceeded with a simulated countdown up to the moment before the engines would be ignited to test all of the systems on both the spacecraft and the ground. The test was reportedly a complete success with no problems discovered. It will be drained of fuel and returned to its hangar Friday.

There is one more major milestone test to be completed before SpaceX will be ready to launch. That will be the “Hot fire” test where the nine first stage engines will be fired briefly as a final check of all systems. That test will happen about two weeks before the actual launch, which is tentatively planned for late April.

Once the Dragon spacecraft is launched into orbit, it will rendezvous with the International Space Station. There, astronauts on board the ISS will use the Canada Arm 2 robotic arm to grapple the Dragon and berth it to the station. The astronauts will then open the spacecraft to remove the supplies and equipment stored on board. They will then load equipment and materials from the results of various experiments into the Dragon before releasing it from the space station.

The Dragon will then reenter the earth’s atmosphere and splash down in the Pacific ocean near a waiting recovery team, becoming the only vehicle to return materials from the ISS except for NASA’s Space Shuttles, which were retired last year.