Editing Metallic hydrogen (section)

===As a rocket propellant===
[[metastability|Metastable]] metallic hydrogen may have potential as a highly efficient rocket propellant; the metallic form would be stored, and the energy of its decompression and conversion to the diatomic gaseous form when released through a nozzle used to generate thrust, with a theoretical [[specific impulse]] of up to 1700 seconds (for reference, the current most efficient chemical rocket propellants have an {{math|''I''{{sub|sp}}}} less than 500 s<ref name=":3">{{Cite journal |last1=Silvera |first1=Isaac F. |last2=Cole |first2=John W. |date=2010 |title=Metallic Hydrogen: The Most Powerful Rocket Fuel Yet To Exist |url=https://dash.harvard.edu/handle/1/9569212 |journal=Journal of Physics: Conference Series |volume=215 |issue=1 |page=012194 |doi=10.1088/1742-6596/215/1/012194 |bibcode=2010JPhCS.215a2194S |s2cid=250688957 |language=en-US |issn=1742-6596|doi-access=free }}</ref>), although a metastable form suitable for mass-production and conventional high-volume storage may not exist.<ref>{{cite conference|title=Metallic Hydrogen: The Most Powerful Rocket Fuel Yet To Exist|conference=Proceedings of the International Conference on High Pressure Science and Technology|date=July 2009|url=https://dash.harvard.edu/bitstream/handle/1/9569212/Silvera_Metallic.pdf|last1=Silvera|first1=Isaac F.|last2=Cole|first2=John W.|journal=Journal of Physics: Conference Series |volume=215|issue=1|page=012194|doi=10.1088/1742-6596/215/1/012194|bibcode=2010JPhCS.215a2194S|doi-access=free}}</ref><ref>{{cite journal|title=On the lifetime of metastable metallic hydrogen|journal=Low Temperature Physics|volume=43|issue=10|date=29 December 2017|last1=Burmistrov|first1=S.N.|last2=Dubovskii|first2=L.B.|pages=1152–1162|doi=10.1063/1.5008406|arxiv=1611.02593|bibcode=2017LTP....43.1152B|s2cid=119020689}}</ref> Another significant issue is the heat of the reaction, which at over 6000 K is too high for any known engine materials to be used. This would necessitate diluting the metallic hydrogen with water or liquid hydrogen, a mixture that would still provide a significant performance boost over current propellants.<ref name=":3" />