Curiosity, like all rovers on Mars, doesn't float away because Mars has gravity. Although it's only about 38% of Earth's gravity, it's still enough to keep Curiosity firmly planted on the Martian surface.

Here's a breakdown:

* Gravity: Mars has a gravitational pull, though weaker than Earth's. This pull keeps Curiosity, and everything else, grounded.

* Weight: Curiosity has a significant weight, about 900 kg (2,000 lb). This weight is further amplified by the force of gravity on Mars.

* Wheels: The rover's wheels provide additional traction and grip, further preventing it from lifting off the ground.

* Design: Curiosity's design is specifically engineered to withstand the Martian environment and remain stable.

In short, Curiosity is firmly planted on Mars due to the combined forces of gravity, its own weight, and its well-designed structure. It's not floating away!