A scalable gravity offload device simulates reduced gravity for the testing of various surface system elements such as mobile robots, excavators, habitats, and deployables in a relevant environment. The device is capable of simulating reduced gravity over an arbitrary terrain including such features as slopes, obstacles, and varying surface concavity. The device consists of a linear movement system, a 2 degree-of-freedom manipulator, a passive force application mechanism, and a position tracking mechanism. The manipulator travels along the linear movement system and is positioned perpendicular to the linear movement system's direction of travel. The result is a rectangular working area whereby the gravity offload device can simulate reduced gravity in the area defined by the length of the linear movement system by the width (reach) of the 2 degree-of-freedom manipulator. The force application mechanism is principled upon precision maintenance of a pressure in an air cylinder. Precision regulation of supply pressure enables constant force over the throw of the air cylinder. Varying the regulator supply pressure to the air cylinder(s) modifies the force experienced by the test article and therefore enables a gravity offload device to simulate a range of gravity fields proportional to the ability to regulate pressure.