To make mars a feasible planet,it must have a strong magnetic field. To create a magnetic field,mars needs iron. I have repeatedly said this.seems nasa agrees without saying as its now come out with an article talking about where most asteroids are located. Redirecting these asteroids at mars would have the added bonus of them not getting launched at earth.a win win,imho. Getting the largest iron asteroids moved first would be priority. I think its time we focussed some nasa revenue on plans for these asteroids. Im currently searching for a survey of them and a map.
If we could come up with a gravity amplifier that is always just little stronger each time,we could land it on a rock and have it start attracting more until we have a clump.then direct the clump at mars.we could land these,equally spaced out around the ring.this way the work is done on its own and keeps men and machines out of the chaos.saves on energy resources for the space craft. If the gravity amplifiers were strong enough.it wouldnt take much time with gravity at 30ft per second,per second.plus protect against strays getting away. A portion could also be used as a mini moon to help with tides after we get the water melted.tides are neccessary for sustainable life.