It is an intriguing concept, and I can see where it could be a desirable goal (Even if nothing else than to have easy access to something we might end up trying to use to deflect something larger.
However, even with all the rigorous peer reviewed calculations and advanced math NASA is known for, what concerns me, is the way we approach scientific ideas like this, yet fail to calculate for unexpected variables.
Given the moon and earth have a symbiotic gravitational relationship does it really make a lot of sense to tinker with highly functional gravitational equilibrium? What if we do something like this and within 2 years start to see ocean life dying out, within 5 the atmospheric regulation becomes destabilized failing to properly cleanse CO2 out of the atmosphere, and by the time we get a grasp on what the problem actually is, there is no way to repair it because even removing the interference will not perfectly restore the original equilibrium to jump start those ecological systems back into functioning.
Not saying that is scientifically feasible, Its just the first example of not paying attention to come to mind when reading this. Just saying science does have a long and storied history of leaping before you look.
For all the great things NASA and the scientific community have given the world thru the ages, I learned to never completely trust a guy who would willingly prioritize their hair, zits and dick over threats that will eat you alive both inside and out.
Edit:
RicoADF said:
Am I the only one who's first concern was not impact, but rather the effects of another large objects gravity on earth? that's before I read its 7m long
Nope, but ya ninja'd me to the punch. While 7 meters is not huge, we are potentially tinkering with systems that we do not fully understand. We really cannot effectively predict every nuanced effect a little rock might have. Simple butterfly effect in action.