Soyuz-5, also known as Irtysh, is the new generation medium-class launch vehicle developed by Russia in cooperation with Kazakhstan to replace the Zenit-2 and Proton Medium launch vehicles, and to keep Baikonur cosmodrome operational while Vostochny cosmodrome takes on the role of the main Russian spaceport. It was previously known as project Sunkar/Fenix. The first stage of this launch vehicle will be used in the planned super-heavy Yenisey rocket, capable of lifting 100 tons of payload to low Earth orbit, and is considered the first stage in achieving this goal. Live firing tests of the fully intergrated first stage of Soyuz-5 were completed in March 2025. It is currently unclear whether the test flight will carry a mass simulator or a functional payload.