Heating occurs due to the adiabatic compression of gas (a great bow shock is formed, with high compression of the air, causing very high temperatures - friction does not cause the heating as it often thought). Tungsten does have a high melting temp - but it oxidizes rapidly at high temperatures - so not sure if the rods would be very large by the time they struck the surface (a lot would burn up in the atmosphere).

As mentioned by frogesque, aiming such a "rod" projectile very accurately is basically impossible - that is why they "fly" the space shuttle onto the landing strip. This is a "weapon" that has no future until your put guidance wings on it. I would imagine it is much cheaper and easier just to take off and land (explosively) like high range missiles do. That can be pretty damaging without resort to orbiting heavy metals above our heads.

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Michael W S