[Randallw]

1. I don't believe there is a way to tell the ships to stay close to your planet. They will move towards the enemy ships, unless they are unarmed or told not to get hurt in which case they will try to move as far from the enemy as possible.

2. In your case of a minefield with 30 mines, if you move a ship capable of removing 15 mines then it will remove 15 but then be damaged by the ones left. Minesweepers are not immune to mines they do not remove in 1 turn. You need more than 1 minesweeper but minefields are limited to up to 120 mines, at least in most games I've played.