State five distinct propulsion technology challenges involve

State five distinct propulsion technology challenges involved with just one of the following: a) High bypass ratio turbofan engines with ultra-low thrust-specific fuel consumption. b) Reusable Single-Stage-to-Orbit rocket launch vehicles using liquid hydrogen and oxygen propellants. c) Hypersonic scramjets

Solution

HYPERSONIC SCRAMJET

1.Expensive test and development

2.Very high initial propulsion requirement

3.Efficient thrust cannot be achieved unless boosted to high speed

4.Poor thrust to weightbratio

5.Maintaining combustion is difficult