Sweet I am now 99% sure one of my theories from last episode is right, there is a secret Shield Space station, and that's where slingshot is taking the items. When Coulson was detailing how deeply he wanted that element buried and secret, to that agent that was putting it into storage because that's what Hall would have wanted, he specifically mentioned He did not want it flagged for the slingshot. Coulson makes it quite clear that he never wants this stuff to be touched again, and yet he specifically dose not want it to be flagged for slingshot, which would send it into the sun, that would guarantee it was never touched again. Graviton is implied to be very dangerous, and I'd have to say it sure seems to far more dangerous than the Hydra Ray weapon last episode, that when fired only put a relatively small hole in the side of a plane, but was "too dangerous for any person or government to have."