Is it possible to "block" an orbital trajectory by dispersing shrapnel or any other compound that consists of many small yet destructive particles? Basically, a multitude of projectiles or a very large warhead is launched into the target orbit (can be even retrograde if it is an Equatorial orbit) and then explodes, dispersing shrapnel. If multiple projectiles are used, then a whole Low Earth Orbit can quickly be clotted. When an enemy spacecraft tries to enter the orbit, it is immediately hit and destroyed by the shrapnel. The shrapnel could possibly be made magnetic so that it "falls" towards spacecraft. After several years, most of the shrapnel will be gone due to orbital decay. What do you think of my idea?