An overview of space tests searching for small deviations from special
relativity arising at the Planck scale is given. Potential high-sensitivity
space-based experiments include ones with atomic clocks, masers, and
electromagnetic cavities. We show that a significant portion of the coefficient
space in the Standard-Model Extension, a framework that covers the full
spectrum of possible effects, can be accessed using space tests. Some remarks
on Lorentz violation in the gravitational sector are also given.Comment: 12 pages, invited talk at International Workshop, From Quantum to
Cosmos, Warrenton, VA, USA, May 22-24, 200