SpaceX Dragon capsule, carrying Americans Kjell Lindgren, Bob Hines and Jessica Watkins, and Italian Samantha Cristoforetti of the European Space Agency, docked at the International Space Station on Wednesday night.
Crew-4 is due to carry out hundreds of scientific experiments, including ongoing research into growing plants without soil in space.
Another involves developing an artificial human retina, leveraging the microgravity environment of the ISS to help deposit layer after layer of thin films of protein.
The technology "could eventually be used to replace damaged photoreceptor cells in the eyes and potentially restore meaningful vision to the millions of people who suffer from retinal degenerative disease," said NASA scientist Heidi Parris.
Among the crewmates, Watkins is only the fifth Black woman to go to space, and the first to join the crew of the ISS on an extended mission.