Proton-M

The Proton-M is a russian carrier rocket that first flew in 2001. The Proton-M is known for its toxic propellants: Nitrogen Tetroxide as the oxidiser, and Unsymmetrical Dimethylhydrazine as the fuel. The Proton rocket has a first stage with 6 RD-275 engines, a second stage with 3 RD-0210 and 1 RD-0211, and a third stage with 1 RD-0212. The fourth stage could either be a Briz-M or a Block-DM. The proton flew without a fourth stage only for launching space station modules to LEO. This included all the Salyut Space Stations, all of Mir’s modules, and the ISS modules Zarya, Zvezda, and Nauka. The Proton-M is currently planned to be replaced by the Angara-A5. This is because that the Angara-A5 doesn’t use hazardous fuels like the Proton does.