  Theory and computations are provided for building of optimal (minimum weight)
solid space towers (mast) up to one hundred kilometers in height. These towers
can be used for tourism; scientific observation of space, observation of the
Earth surface, weather and upper atmosphere experiment, and for radio,
television, and communication transmissions. These towers can also be used to
launch spaceships and Earth satellites.
  These macroprojects are not expensive. They require strong hard material
(steel). Towers can be built using present technology. Towers can be used (for
tourism, communication, etc.) during the construction process and provide
self-financing for further construction. The tower design does not require
human work at high altitudes; the tower is separated into sections; all
construction can be done at the Earth surface.
  The transport system for a tower consists of a small engine (used only for
friction compensation) located at the Earth surface.
  Problems involving security, control, repair, and stability of the proposed
towers are addressed in other cited publications.
