Expedition 40
The Expedition 40 crew gathers in the International Space Station's Zvezda service module to receive congratulatory calls for the three newest crew members. NASA TV

Three new astronauts arrived at the International Space Station, or ISS, at 11:52 p.m. EDT on Wednesday, expanding the number of Expedition 40 crew members inside the orbital laboratory to six.

The new Expedition 40 trio, including Reid Wiseman of NASA, Soyuz commander and cosmonaut Max Suraev of the Russian Federal Space Agency and Alexander Gerst of the European Space Agency, will spend 166 days aboard the ISS. During this period, five spacewalks -- two by Russia and three by the U.S. -- have been planned, according to NASA.

“Commander Steve Swanson of NASA and Flight Engineers Oleg Artemyev and Alexander Skvortsov of Roscosmos, who have been aboard the orbiting complex since March 27, warmly greeted the newly arrived flight engineers,” the space agency said in a statement.

Wiseman, Suraev and Gerst were launched from Baikonur in Kazakhstan at 3:57 p.m. EDT and the Soyuz docked automatically with the Earth-facing port of the station’s Rassvet Mini-Research Module-1 at 9:44 p.m. EDT, NASA said, adding that some of the cargo flown aboard the Soyuz would be used for new as well as ongoing research aboard the ISS.

During its tenure, the Expedition 40 crew will perform research in the subjects of humans in space, biology and biotechnology, Earth and space science and physical science investigations, and conduct technology demonstrations and educational activities. Results from these research projects are expected to lead to improved weather forecasts and medical advancements on Earth.

According to NASA, the required hardware and samples for many of these experiments, along with crew supplies and other cargo, will arrive on four different resupply vehicles scheduled to visit the station during Expedition 40.

Swanson, Skvortsov and Artemyev are scheduled to head back to Earth on Sept. 10, marking the end of Expedition 40 and the beginning of Expedition 41 under the command of Suraev. Three additional Expedition 41 crew members will arrive later that month.