"Many rockets today use liquid oxygen and/or liquid hydrogen – the same main fuels used in NASA’s space shuttle program, for example, which ran for 30 years between 1981 and 2011...Matier used to examine rocket fuel alternatives as a former engineering manager at NASA’s White Sands Test Facility, where he worked for 16 years during the space shuttle era. “The drawback, the holdback, the thing from stopping that development is there is nothing [green] that is hypergolic – it won’t burn upon mixing,” he told SpaceQ. “That’s the key … they require spark plugs. Those are not reliable and add weight, complexity and risk."
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