Emirati astronaut Sultan Al Neyadi and his colleagues are set to take over the previous crew's activities on the International Space Station, including science experiments and maintenance tasks.
Expedition 68 crew members will leave the orbiting laboratory on Saturday after a five-month mission in space.
The four departing astronauts - Nasa's Nicole Mann and Josh Cassada, Japan's Koichi Wakata and Russia's Anna Kikina - will splashdown off the coast of Florida.
Dr Al Neyadi and his crewmates, Stephen Bowen, Woody Hoburg and Andrey Fedyaev, arrived on the station as their replacement on March 3 for a six-month mission as part of Expedition 69.
"Four Expedition 68 crew members are nearing the end of their stay aboard the International Space Station this weekend," Nasa said.
"Their replacements are completing their first week aboard the orbital outpost and getting up to speed with life in space."
Dr Al Neyadi has already started carrying out tasks, including picking tomatoes that were planted by Ms Mann in December.
He has also been spending time in Japan's Kibo module, a segment on the station where astronauts perform science experiments and maintenance work.
"The four new station residents have started exploring how microgravity affects the human body and picked a small tomato crop growing for a space agriculture study," Nasa said.
"They also spent Thursday afternoon familiarising themselves with space station hardware and emergency equipment located throughout the space lab."
Dr Al Neyadi and his colleagues will be responsible for carrying out more than 200 experiments assigned by Nasa, and the Emirati will also take part in 19 experiments given by UAE universities.
Fresh supplies are also being sent up on March 15 on a SpaceX cargo resupply mission, which will deliver experiments, food and other items to the new astronauts on board the station.
There are currently 11 people on the ISS, including the station's commander Sergey Prokopyev, flight engineer Dmitri Petelin, both from Roscosmos, and Nasa flight engineer Frank Rubio.
They were supposed to return to Earth last month, but the Soyuz spacecraft they had arrived on suffered catastrophic damage from a micrometeorite.
A replacement Soyuz was sent up and will bring the astronauts back home in September.
This means the crew will complete a year in space and their replacements will be sent once they are back.
On May 12, four private astronauts, including two from Saudi Arabia, will travel to the ISS for a 10-day stay.
The Axiom-2 mission will lift off on a SpaceX Falcon 9 rocket from the Kennedy Space Centre in Florida.
The Saudi astronauts are Ali Al Qarni and Rayyanah Barnawi, who is set to become the first Arab woman in space.
This will bring the total number of Arabs in space together at once to a record number of three.
