The lowest cost/Kg was the Saturn 5. A rocket does not, of course,
need any ballast as its engines are directly underneath.

There are in fact two routes to lower cost spaceflight. One is a
reusable vehicle where wings are always envisaged, the other is to
rationalize on one type of rocket, mass produce and cut the production
cost. The first solution is the one NASA has tried and failed at. The
second is far more pragmatic, it lacks elegance but it would produce
real cost savings.


- Ian Parker