The commercially developed SpaceX Crew Dragon ship carrying a group of four U.S. and Japanese astronauts successfully docked with the International Space Station on Monday following its liftoff from NASA's space center a day earlier.

The commercially developed SpaceX Crew Dragon ship approaches the International Space Station, as seen on NASA TV. (Photo courtesy of NASA TV)(Kyodo)

Three NASA astronauts -- Michael Hopkins, Victor Glover and Shannon Walker -- along with Soichi Noguchi of the Japan Aerospace Exploration Agency will begin a six-month mission at the orbiting laboratory.

Clad in red T-shirts, the four astronauts smiled and waved during a welcome ceremony at the ISS.

"Words can't express how I'm feeling to be able to return to the ISS," Noguchi said.

Referring to the coronavirus pandemic, he added, "We have christened the crew 'Resilience' to say we will overcome recent hardships."

"This mission was a dream, to be able to have crew transportation services to the ISS, and today that dream became a reality," said Kathy Lueders, associate administrator of the Human Exploration and Operations Mission Directorate at NASA, during a press conference later the same day.

"I'm happy about this great success," Japanese Prime Minister Yoshihide Suga wrote on his official Twitter account. He offered his congratulations to the crew and noted that he looked forward to seeing "amazing results" from the mission.

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The second manned flight to the ISS by the Crew Dragon capsule, developed by the U.S. company Space Exploration Technologies Corp., followed a test flight earlier this year with two NASA astronauts.

Noguchi, 55, became the first non-American astronaut to be ferried by NASA's first-ever certified commercial human spacecraft system.

The SpaceX system is expected to serve as a successor to NASA's Space Shuttle program that was in service for 30 years through 2011, its development ending the subsequent years of reliance on the Russian Soyuz vehicle as the sole means of accessing the ISS.

Seats in the Soyuz have cost NASA around $80 million or more each in recent years, according to a 2019 report by the U.S. space agency's Office of Inspector General. The National Aeronautics and Space Administration hopes to reduce crew transportation costs through commercial systems developed in the United States.

The latest development is welcome news for Japan, which also has had to rely on the Soyuz vehicle to send its astronauts to the ISS.

Noguchi is a veteran astronaut with experience from two previous space missions, having been aboard the Space Shuttle Discovery in 2005 and a Russian Soyuz spacecraft for a 161-day stay on the ISS between 2009 and 2010.

During his present stay on the ISS through April, Noguchi is expected to carry out experiments involving iPS cells, or induced pluripotent stem cells, that can be converted into any type of cell in the body, according to JAXA.

NASA officials have highlighted the importance of sending more astronauts to the ISS, which increases the capacity for scientific research in space.

The arrival of the four astronauts raises the total number of crew members aboard the ISS to seven. Permanent human occupancy of the station began in November 2000.

Screengrab from NASA TV shows the commercially developed SpaceX Crew Dragon ship docked with the International Space Station. (Kyodo)

Screengrab from NASA TV shows Japanese astronaut Soichi Noguchi (2nd from R) waving aboard the International Space Station. (Kyodo)