Bethesda, MD (SPX) Jun 01, 2016
Many innovators have proposed a variety of concepts that might propel a launch vehicle from Earth to orbit. However, only two basic types of rocket engines have survived the test of fire: Solid propellant and liquid propellant rockets. There are still a few who believe hybrids are the answer to achieving orbital speeds with meaningful payloads. However, none of the liquid/solid contraption
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