Russian cosmonauts sit aboard a space station dressed in blue, yellow and Ukrainian: NPR

Three Russian cosmonauts boarded the International Space Station dressed in yellow and blue, in a clear statement of support for Ukraine.

Wearing the colors of the Ukrainian flag is widely seen as a way to oppose the Russian invasion of Ukraine.

The three cosmonauts, Oleg Artemyev, Denis Matveev and Sergey Korsakov, docked their Soyuz MS-21 spacecraft on Friday. The expedition was planned for six months.

In a live docking broadcast, Artemyev is seen wearing an all-blue spacesuit before entering the International Space Station. When they entered from the hatch, the three of them were wearing yellow spacesuits with blue ones. The Russian flag also appeared on their space suits.

It is not yet clear what message the astronauts were trying to send. But when asked about the yellow suits, Artemyev said that each crew chooses their own clothes.

He said, “It was our turn to choose the color. But in reality, we had accumulated a lot of yellow matter, so we needed to use it. That is why we had to wear yellow,” according to News agency.

In recent weeks since the Russian invasion of Ukraine, there have been concerns about space relationships between the United States and Russia. While geopolitical tensions on the ground have remained somewhat separate from how the United States and Russia work together in the space endeavour, some officials said the latest conflict is very different from previous ones.

The three Russians join two other Russians who were already aboard the International Space Station, along with four Americans and a German cosmonaut.