The SXT-244 is a space shuttle. This one have a scramjet engine for fuel efficiently climb into atmosphere and rocket engine for space flight. As first stage used solid rocket booster as the Space Shuttle.
It uses rocket boosters only at the initial stage, for takeoff and acceleration to Mach 3.
After that, scramjet was ignite and accelerate it to Mach 10-15, without leaving the atmosphere. Only after reaching this speed used liquid rocket engine, for leaving from atmosphere and for accelerate to orbital velocity.