In what sounds like a plotline from a mid-'80s Cold War movie, Russia's building a hypersonic stealth bomber called the PAK-DA that'll be invisible to radar, able to get over any spot on Earth in two hours and launch a nuclear attack from space.
According to Colonel Alexei Solodovnikov, the PAK-DA strategic bomber project's general contractor and a professor of Strategic Missile Forces at the Military Academy, the hybrid air-and-space plane will take off from a regular airfield burning traditional kerosene, then switch to a methane-oxygen mix when it leaves our atmosphere, at which point it could drop nukes "if needed." Russia's Defense Ministry is quick to stress that that scary ballistic scenario is merely "hypothetical."
The PAK-DA is being designed by Russian aerospace firm Tupolev. General Sergei Karakayev, commander of Russian Strategic Missile Forces, claimed a model for the engine has already been built and tested. The next couple years they'll be working on the hardware to go with it. And they aggressively hope to have a fully operational prototype by 2020.
In the meantime, perhaps this coming September's International Military-Technical Forum in Moscow will shed some light on the bomber's development and readiness.