Russian intercontinental boost-glide missile. Version that would boost the Raketoplan combat re-entry vehicle, which would use aerodynamic horizontal and vertical maneuvering to penetrate enemy space defenses and be practically invulnerable.
These re-entry vehicles were of unique concept and consisted of a high-fineness oblique conical heat shield with petal-like maneuvering flaps at the base. They were capable of very large cross-range maneuvers (up to 3000 km).