— Medallions for the 50th anniversary of the first time that Russia and the United States worked together in space have launched to the International Space Station on a Russian rocket specially decorated for the occasion.

The Apollo-Soyuz Test Project (ASTP) golden commemoratives were packed on board Roscosmos' Progress MS-31 (92P) uncrewed cargo spacecraft that lifted off atop a Soyuz 2.1a rocket from Site 31/6 at the Baikonur Cosmodrome in Kazakhstan on Thursday (July 3) at 3:32 p.m. EDT (1932 GMT or 12:32 a.m. local time on July 4). The venerable launcher, which is a later model of the booster that gave start to the Russian side of the historic ASTP mission on July 15, 1975, bore a special white and blue livery as a nod to the five-decade milestone.

It is only the second time that a Soyuz 2 rocket has been painted in such colors after a similar tribute to the world's first human spaceflight in 2021. Thursday's launch vehicle also sported a logo denoting the 50 years since the ASTP mission.

The medals and emblems, as well as perhaps other still-to-be-disclosed items stowed aboard Progress MS-31, were Roscosmos' way of recognizing the first meeting of Russian cosmonauts and American astronauts in Earth orbit to exchange handshakes, a good meal and symbolic gifts and tokens of goodwill.

The last launch of an Apollo command module carried astronauts Thomas Stafford, Vance Brand and Deke Slayton to meet up with and dock with cosmonauts Alexei Leonov and Valery Kubasov aboard a Soyuz spacecraft. Over the course of more than 40 hours of docked operations, the Cold War adversaries demonstrated it was possible to also collaborate in space.

The framework established by the ASTP mission was credited with setting the foundation for the International Space Station, including the visits by the U.S. space shuttle to the now-former Russian space station Mir in the late 1990s and the exchange of crew members on spacecraft launching and returning from the orbital complex that continue to this day.

Although tensions have increased between the two countries again, American astronauts and Russian cosmonauts work together aboard the space station, as they have since a continuous human presence was established on the ISS 25 years ago this November.

Whether intentional or not, the flight of the 50th anniversary ASTP coins evoke silver medallions and commemorative medals that flew on the 1975 mission. The latter were designed so one half of each medal launched with the U.S. crew and the other with the Soviet contingent and then they were assembled in space.

It is unknown how many of the 2025 medallions are aboard Progress MS-31. They each have the Apollo-Soyuz program logo on one side, augmented by the years 1975 and 2025. On the reverse, are the names of the ASTP crew members lining the border and the Soyuz MS-27 crew — NASA astronaut Jonny Kim and Roscosmos cosmonauts Sergey Ryzhikov and Alexey Ryzhikov — listed at center.

Ryzhikov, Ryzhikov and Kim also paid tribute to the ASTP anniversary by including the program logo with a "50" at its center as part of their mission patch design.

The Soyuz MS-27 crew, together with JAXA (Japan Aerospace Exploration Agency) astronaut Takuya Onishi, Roscosmos cosmonaut Kirill Peskov and NASA astronauts Anne McClain and Nichole Ayers, are on board the space station to receive the supply ship when it arrives on Saturday (June 5).

In addition to commemoratives, Progress MS-31 is packed with about three tons of food, fuel, and supplies for use by the Expedition 73 crew. The spacecraft is the 184th Progress to fly since 1978 and the 92nd to be launched in support of the International Space Station program.