All deep-space engineers and thinkers must be excited by the announcement by two physicists that they have successfully created metallic hydrogen. I read about it a Science Daily website today. The two used a new version of a diamond anvil to generate enormous pressure and they confirmed the actual presence and properties of metallic hydrogen. The article went on to postulate that the metallic hydrogen may very well be metastable. It would exist at normal pressure and temperatures once created, much as carbon is crushed inside the earth to form diamonds. Which of course maintain their unique properties when on the surface of the earth as a diamond ring or what have you. The predicted Specific Impulse of metallic hydrogen is nearly four times higher than the typical molecular hydrogen used in many rocket engines today. This huge increase would mean greater payloads and higher transit velocities out to the planets if in fact the metallic hydrogen is metastable and can somehow be produced in a fairly economical way for space explorations.