ecules impact spacecraft surfaces with sufficient energy to sever the chemical bond of surface atoms. AO is known to interact with a wide variety of materials, resulting in erosion and degradation of the properties of the surface material. Mitigation provisions for neutral environment effects include the choice of altitude which reduces the exposure, choice of materials which are resistant to chemical degradation and exhibiting high sputtering threshold, the use of coatings to protect surfaces, orienting sensitive surfaces and devices away from the ram direction, and reducing aerodynamic drag by reducing the space vehicle cross section. Micrometeoroid and Orbit Debris [Loftus97] The naturally occurring background of particles and objects present in the near-Earth environment are termed micrometeoroids. The man-made component of objects present in this environment is orbit debris. The primary concern from both micrometeoroid and orbit debris presence is the physical damage resulting from impact with the spacecraft. Even though the size and mass of these objects is relatively small, they produce profound consequences through hypervelocity impact effects. The micrometeoroid flux is episodic, as evidenced by annual encounters with Perseid and Leonid populations. The primary sources of debris have been explosions in space (unstable propellant at end- of-life, breakups, and collisions with orbit debris), solid rocket fuel particulates, and surface erosion particulates (paint chips, etc.). All of the launch organizations have made modifications to preclude future inadvertent explosions due to residual propellants. Current space operators have initiated voluntary efforts to protect the future space environment. They have adequate incentive to follow through on these initiatives; it is their assets which are at risk. Due to their origin, orbit debris is present in the most often used orbits, and will impact spacecraft mainly in the ram direction, with velocities which are less than micrometeoroids. The orbit debris popula