MOSCOW (AP) — Six decades after Sputnik, a refined version of the rocket that put the first artificial satellite in orbit remains the mainstay of Russia's space program — a stunning tribute to the country's technological prowess, but also a sign it has failed to build upon its achievements.

And unlike the Cold War era, when space was a key area of the rivalry between the United States and the Soviet Union, space research now appears to rank low on the Kremlin's priorities.

The Soyuz booster, currently the only vehicle that launches crews to the International Space Station, is a modification of...