Washington DC [USA], June 1 (ANI): Two NASA astronauts crossed over into the International Space Station on Sunday after their Crew Dragon capsule docked with the orbital outpost after an hours-long space journey.

"This is the first time in human history @NASA_Astronauts have entered the @Space_Station from a commercially-made spacecraft. @AstroBehnken and @Astro_Doug have finally arrived at the orbiting laboratory in @SpaceX's Dragon Endeavour spacecraft," NASA tweeted.

"It was a tremendous day in mission control as we watched the Dragon approach and then dock, and the hatch open and have @AstroBehnken and @Astro_Doug come forward into the @Space_Station," said NASA Johnson Center Director Mark Geyer.

The US space agency posted a video of Bob Behnken and Doug Hurley stepping into the ISS and being greeted by the three spacefarers who had been living on its board for months.

US billionaire Elon Musk's SpaceX company built the Dragon module that lifted off from the Florida spaceport on Saturday, after days of delay. This was the first launch from US soil since NASA retired its space shuttle program in 2011.

On Wednesday, the planned launch was called off due to bad weather.

Behnken is the joint operations commander for the Demo-2 mission, responsible for activities such as rendezvous, docking and undocking, as well as activities while the spacecraft is docked to the space station. He was selected as a NASA astronaut in 2000 and has completed two space shuttle flights.

Hurley the spacecraft commander for the mission, responsible for activities such as launch, landing and recovery, was selected as an astronaut in 2000 and has completed two spaceflights. (ANI)