Rus-M

Rus-M was a proposed Russian launch vehicle design that was meant to become the country's main launcher for crewed spaceflight after 2018, and an integral part of the Orel spacecraft being developed to replace the Soyuz. TsSKB-Progress, the predecessor of today's Progress Rocket Space Centre, began developing it in 2009 under a government contract. Roscosmos asked for an extremely reliable rocket with safe abort options at every stage of flight. Four variants were planned, built from a varying number of common cores each powered by a single RD-180 engine burning kerosene and liquid oxygen, with an upper stage using four RD-0146 hydrogen engines or a kerosene stage shared with Soyuz-2. The first version was to lift 23.8 tons to low orbit and later versions up to 50 tons. The programme was halted in October 2011, restarted in 2012 and finally cancelled in August 2015, and the Soyuz-5 concept, later named Irtysh, became its successor. It never flew.