Astro Galaxy - a realistic space exploration game

Defending your planetary facilities, orbital stations.

When attacked, all the units belonging to the defender will enter battle. Thus, having a ship in orbit will protect your weak mining outposts on planet and the small orbital station you will have. It is imperative that you keep the ship(s) in orbit to protect it, as the facilities will be very vulnerable at the beginning. A single ship with a weapon module can blast a lone  mining facility from space, with little to no damage for the attacker ship, as the weapon fires first and the mining facility only has civilians on it.

Next step is to barricade your foothold on the planet. Add additional modules on planet, like weapons, shields, marine assault units. Everything helps. Orbital stations should be equipped with weapons, shields, armor to the best you can muster. Take note that planetary facilities and orbital stations can not flee if attacked, and will fight until destroyed.

Having a ship in orbit will also provide some time to evacuate. If you have a bigger force on planet and orbit, the attacker will also need a big force. This will make attacking / maneuvering take some time, maybe even hours. This will provide you with ample time to gather everything and escape into space. There is no shame in retreating from a much more powerful opponent...