An extreme environment Flywheel Energy Storage system for small spacecraft capable of operating at the Lunar day/night temperature extremes could benefit future Lunar missions like the Resource Prospector Mission or Lunar Quest. In addition, NASA will benefit from commercial ventures that employ this technology as science and technology demonstrations will be more affordable for NASA. NASA Outer Planets missions would also benefit from an FES such as the one proposed. Beyond NASA and "Commercial Space" applications, other potential applications exist on Earth. These include (1) UAV power supplies, (2) Subsea ROV/UUV power supplies , (3) Downhole/In-Well power supplies for oil & gas industry. An extreme temperature FES "batteries" could potentially allow downhole logging equipment to operate at greater depths than those attainable using these existing high temperature batteries. Honeybee has received interest from oil and gas companies looking for alternative to electrochemical batteries. The advancement of the technology during the proposed effort will go a long way towards reducing technical risk, not just for planetary exploration, but for the application to terrestrial environments as well.