NASA astronaut Jessica Meir and two fellow crew members arrived Wednesday for their mission aboard the International Space Station, temporarily increasing the orbiting laboratory’s population to nine people.

The Soyuz MS-15 spacecraft carrying Meir, Oleg Skripochka of the Russian space agency Roscosmos, and the first space traveler from the United Arab Emirates (UAE), Hazzaa Ali Almansoori, launched at 9:57 a.m. EDT (6:57 p.m. Kazakhstan time) from the Baikonur Cosmodrome in Kazakhstan. Their spacecraft docked to the station’s Zvezda service module at 3:42 p.m., after a four-orbit, six-hour flight. They are scheduled to open hatches between the Soyuz and the International Space Station to be welcomed aboard the orbiting laboratory around 5:45 p.m.

After the hatches open, station commander Alexey Ovchinin of Roscosmos, along with NASA astronauts Christina Koch, Nick Hague, Andrew Morgan, ESA (European Space Agency) astronaut Luca Parmitano and cosmonaut Alexander Skvortsov, will greet the new residents.

The eight days between the trio’s arrival and the departure of Soyuz MS-12 spacecraft will see the largest crew aboard the station since September 2015, when nine crew members were aboard for seven days during Scott Kelly and Mikhail Kornienko’s year-long mission.

Meir and Skripochka will spend more than six months on the station. Almansoori’s eight-day mission as a spaceflight participant under an intergovernmental contract between the UAE and Roscosmos will come to an end when he returns to Earth Thursday, Oct. 3 on the Soyuz MS-12 spacecraft, along with Hague and Ovchinin, who are completing more than 200 days in space.

The Expedition 61 crew will spend more than six months conducting about 250 science investigations in fields such as biology, Earth science, human research, physical sciences, and technology development. Work on the unique microgravity laboratory advances scientific knowledge and demonstrates new technologies, making research breakthroughs that will enable long-duration human and robotic exploration of the Moon and Mars.

During Expedition 61, crew members will install new lithium-ion batteries for two of the station’s solar array power channels through a series of spacewalks. Later in the expedition, spacewalkers are scheduled to upgrade and repair the Alpha Magnetic Spectrometer, a key science instrument housed outside the station to study dark matter and the origins of the universe.

An additional highlight of the upcoming investigations the crew will facilitate on the orbiting laboratory is the AstroRad Vest. The vest will use the International Space Station as a platform to test the new garment used to protect astronauts from exposure to increased radiation as they prepare to travel farther into deep space to the Moon and later Mars. Through its Artemis program, NASA will send the first woman and next man to the surface the Moon by 2024, as part of its broader Moon to Mars exploration approach.

A global endeavor, more than 230 people from 18 countries have visited the International Space Station, which has hosted more than 2,500 research investigations from researchers in 106 countries.

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