By Kalwinder Kaur
The space robotics research facility of the U.S. Naval Research Laboratory Spacecraft Engineering Department recently acquired a single slab of solid granite-based 75,000 lb Gravity Offset Table (GOT).
Precision honed to within +/-0.0018 inches tolerance across its surface, the Gravity Offset Table (shown right)
A considerable amount of air is required by the spacecraft on earth to 'float' the object in order to mimic the classical mechanics of physics existing in space on full-scale replica. Based on a frictionless, accurate, large surface area, researchers can better replicate the effects of inertia on synthetic objects in space.
At present, specifically designed pre-configured couplers and mating mechanisms enable achieving capture or controlling of spacecraft in orbit. Based on several spacecraft configurations on Earth, researchers need to first demonstrate minimal rates of error in an affordable and efficient manner. This will lead to efficient capturing and servicing of 'free-flying' orbiting spacecraft which does not have any conventional coupling mechanism.
The 20x15 ft, 1.5-ft thick single piece of granite is within +/- 0.0018-in flat across its surface and features Precision Granite. Also, it complies with all federal 'AAA' specifications. NRL researchers will use the precision GOT to accurately simulate the frictionless motion of objects in space and to figure out the dynamics of servicing and docking mechanisms of the satellites on-orbit. This mechanism is critical because of the growing launch costs. Inclusion of new orbiting spacecraft can be compensated by updating or repairing the assets that already exist in Earth orbit.
The 450 cubic-foot, 37.5 T GOT slab was extracted from the Raymond Granite Quarry, Clovis, California. It is considered to be the world’s largest, single slab, precision granite table with high tolerances, through which engineers can simulate the service of full-scale satellite spacecraft with high structural flexibility to a unique, unprecedented degree of accuracy.