Russia’s astronauts enter the space station in yellow and blue flight suits.

The International Space Station has three Russian astronauts on it. After docking at the space station, they wore flight suits of striking colors, similar to the colors of the Ukrainian flag.

The Russian astronauts didn't say anything that would suggest their clothing was political. It was hard to believe it was random. The outfits astronauts wear on a daily basis are subdued. An actress who arrived on the station in November in a red coverall is one of the recent crews from Russia.

The flight suits are usually packed months in advance, but substitute items could have been added at the last moment, according to Eric Berger, a space reporter at the website Ars Technica.

A scientist at the Harvard Center for Astrophysics suggested that the colors of the three astronauts might be those of Bauman Moscow State Technical University. An official from the university spoke on the Russian livestream of the launch.

The head of Russia's space agency, Roscosmos, has responded with a series of provocative messages, including a parody video that suggested Russia would leave behind Mark Vande Hei, a NASA astronaut who is scheduled to return to Earth. Scott Kelly held the record for consecutive days in space by an American until Mr. Vande Hei passed it recently.

NASA officials have ignored Mr. Rogozin's statements and insisted that operations are continuing as usual. They said that there was no change in the plans for Mr. Vande Hei's return.

A pair of crews will fly the Crew Dragon to the station in the coming month, one with a private crew of tourists and the other with a mix of NASA and ESA astronauts.