very imaginative and good series to read.
At that point it's a matter of maneuvering randomly to dodge the kinetic kill munitions. Which certainly involves some luck.
I think direct kinetic weapons only work at long ranges against targets with static movement patterns - ones in regular orbits.
Spaceships can easily dodge projectiles coming from long range, as long as they're looking for trouble.
I think the better option would be some sort of missile bus that released this cluster/shotgun munition at close range in order to ensure a hit.
Only outlaws (terrorists, rogue states) would use machine-guns in space.
nope. The perceived danger of dumb kinetic weapon is a relative speed to the target, ie. kinetic energy. It means that either target or shooter has technological ability to control the energy at respective level. Lets suppose both - i.e. symmetric situation of the same technological levels on both sides. Thus the opponent can deploy similar energy level devices as a defense. For example - today an anti-ship missile can be fought against by using anti-anti-ship missile or guns. New laser defense systems are able in realtime to defend against incoming mortar round today, etc... By the time somebody puts sand in space, an automated laser space junk frying Roombas would be just naturally flying around.
Image throwing a bag of sand at someone running at you. That sort of thing.
(I once discussed space terrorism with someone - they suggested a good way to hold the world to ransom would be to threaten to fly a spaceship full of sand out of the atmosphere, slingshot it around the moon, and slowly sprinkle the sand out the back effectively making it impossible to put anything in orbit again if the world didn't meet your demands.)