It depends on hypersonic gliding maneuvers, the largest supersonic parachute ever deployed, eight hydrazine rocket engines firing in sequence and an elaborate system of tethers called a "sky crane" that are meant to lower the landing craft gently to the ground.

WSJ: NASA's Robot Lab Curiosity Nears Mars

Evidence we have seen suggests that Syrian government forces delivered the 122mm cluster munition rockets containing submunitions using a BM-21 Grad multi-barrel rocket launcher, a truck-mounted system capable of firing 40 rockets nearly simultaneously with a range of 4 to 40 kilometers (2.5 to 25 miles).

CNN: The gruesome toll of deadly cluster bombs in Syria