Abstract: Hypervelocity impact experiments were conducted on fused silica glass to obtain the damage characteristics and to build a damage model using Ly12 aluminum spheres of diameters 1 mm and 3 mm launched by the two-stage-light-gas gun of up to 6.5 km/s, and the small aluminum flyer of 1 mm in diameter and 7 ?m in thickness launched by a laser-driven flyer facility of up to 8.3 km/s, developed by Beijing Institute of Spacecraft Environment (BISEE). The empirical damage equations were obtained to approximately predict the penetration depth (PC) and its diameter (D₁) as a function of impact parameters (projectile velocityVp, mass Mp). For the Ly12 Al projectile of 3 mm diameter sphere, the glass was perforated thoroughly even at a low impact velocity of 2.80 km/s. This means that the projectile diameter plays a major role with respect to the impact damage. The damage feature for the laser-driven small flyer is quite different, and only a shallow pit is formed in the glass surface. But the accumulative damage effects on the glass surface reduce the transmittance significantly. With the M/OD environment, it is suggested that the critical safety thickness (without perforation) of fused silica glass outer windshield is taken as 12 mm for a 400 km altitude orbit space station of 3 year’s life time.