>>11287566People always laugh at me when I say, "sand cannon," when describing space weapons. Little do they know.
As for your idea, knowing the orbital pattern of the sand will help escapes. If you have sand going in many directions and orbital heights then there's no hope beyond big rockets going up well armored. Regardless, a multi-directional orbital sand shroud like that will hit a rocket at no less than 5km/s and as high as 10km/s.
Now, lets say this is a load of beach sand instead of something better. Average weight per sand particle will be 0.0044grains. Speed will be 10km/s. This will have the energy of 14 joules. Comparatively, a .22LR bullet will have an energy of 135 joules when fired from a normal firearm.
To reach something usable destructive, the particles will need to be no less than 1 grain in mass (0.0647989gram) which is comparable to a 7mm mag round or increase the velocity, but that would mean it'd escape to a higher orbit eventually.
1grain: 3,241Joules (7mm mag projectile energy)
2gr: 6,482J
3gr: 9,723J
4gr: 12,964J (10k low end for .50cal BMG projectile energy)
5.1gr: 16,529J (.177cal BB weight/size)
7gr: 22,687J (20k is high end for .50cal BMG projectile energy)
10gr: 32,411J (.177cal airgun lead-pellet weight/size)
17.6gr: 57,043J (20mm 0.11 kg military cannon projectile energy)
30gr: 97,232J (low weight .22LR cal solid point lead projectile)
50gr: 162,053J (high weight .22LR cal solid point lead projectile)
50gr .22cal at 24.84km/s: 1 million Joules (1 stick of TNT)
