Most are observed as a bright streak across the sky that can last for several seconds, but occasionally a large fragment will explode in a multicolored fireball. Most of the streaks are caused by meteoroids about the size of a grain of sand, although meteoroids are porous and much less dense than sand. At its peak, the Perseids produce 50 - 150 meteors per hour. Most of the dramatic streaks we see in the sky are caused by particles that incinerate before they hit the ground. However, satellites and spacecraft can be damaged.
Meteors can poke holes in solar panels, pit surfaces, and short out electronics.
It was discovered in 1994, after the 1993 Leonid meteor storm. Most meteor experts do not expect the Perseids to pose a significant hazard to the more than 2500 commercial, military and science satellites in Earth orbit. The Leonids may be a different story. The result is a spectacular display of 1,000 to 200,000 meteors per hour. The next severe Leonid meteor storm is due this November, and satellite operators are devising stretegies to protect their hardware.