Skepticism
Nobody outside JP Aerospace seems to know how the problems of high drag and low lift/drag ratios that are very typically found at hypersonic speeds might be overcome in such a vehicle, and a large degree of skepticism exists.
An orbital, thermosphere, or even mesosphere airship would face many practical and theoretical challenges and would represent a remarkable technical achievement.
Read more about this topic: Orbital Airship
Famous quotes containing the word skepticism:
“A major problem for Black women, and all people of color, when we are challenged to oppose anti-Semitism, is our profound skepticism that white people can actually be oppressed.”
—Barbara Smith (b. 1946)