Originally posted by Ghost01
The concept was based on the idea that you could skip a spacecraft on the upper atmosphere using the same basic principle that allows you to skip a
flat stone on the surface of a lake. While they never put the concept into practice, the theory is actually quite interesting to read up on.
The basic idea was first seriously proposed by Eugen Sanger for his Antipodal Bomber. The most recent application of it that occurs to me off the top
of my head was the "Hypersoar" concept which added the wrinkle of a scramjet that burned during the low "dips" in the trajectory to boost range.
But skipping for re-entry is no longer considered a good idea... early on it was thought that it would make re-entry heating less of a problem, as
the craft could radiate away the heat during the exoatmospheric upper parts of the trajectory. But it was found that that doesn't work. During the
high-heating phases, the structure of the vehicle absorbs heat, and durign the exoatmospheric phase, when it's supposed to be cooling off, the heat
is instead diffusing into the interior of the vehicle. Conduction turned out to be far more powerful of a heat transfer mechanism than radiation.
