Transformation of Mercury into a Globus Cassus

Background Information

Swiss architect and artist Christian Waldvogel proposed to transform the Earth into into a much bigger, hollow, artificial world with an ecosphere on its inner surface. He called this megastructure "Globus Cassus". All of Earth's matter would be used, and the hydrosphere and atmosphere would be retained on the inside. Sunlight would enter through two large windows, and gravity would be simulated by the centrifugal effect. Once complete, the total habitable area of Globus Cassus would be nine hundred times greater than that of Earth. However, before construction can begin, four massive space elevators are built at four precisely defined points in the geostationary orbit. For more information on the Globus Cassus, click here

Mercury

The problem is, building a space elevator from geostationary orbit to Earth is currently beyond our technological capabilities. However, at locations in the Solar System with weaker gravitational fields, such as the Moon or Mars, we could build a space elevator using 1978 technology. Do you see where I'm going with this?

Mercury has about the same gravitational pull as Mars. Therefore, we could build space elevators on Mercury (if we could find a way to prevent them from melting). The space elevators eventually become towers, and the towers are used to transport silicate building material to the construction sites at geostationary orbit. Bases are built at both of Mercury's poles (the only place possible to build a base on Mercury). The crust, mantle, and core are gradually excavated and transported outward. This serves as building material for the skeleton and shell.

The building material is converted into vacuum-porous aggregate and used to form the skeleton. It is built retaining constant symmetry and balance at every moment and will ultimately span around all sides of Mercury. Then magma is pumped towards the skeleton, where it is used to form thin shells in the skeletal openings. Eight of these openings are fitted with large, inward-curving window domes made out of silicon glass.

What Now?

At this point, in the original Globus Cassus proposal the Earth would have shrunk due to having been used up so much. The polar ice caps would have melted and the Earth's mass, and therefore gravity, would have declined. The atmosphere and hydrosphere would then wander towards the Globus Cassus. Globus Cassus' equator zones would be equipped with a system of trenches and moulds that would become rivers, lakes and seas as soon as the water had settled. The transfer process of atmosphere and hydrosphere is called "The Great Rains".

Things on Mercury won't play out quite like this. Mercury has only a small amount of water in the form of ice at its poles. To avoid exploiting the Earth, most all water would be imported from Europa, Ganymede, or Callisto. Mercury doesn't have an atmosphere either. Oxygen could come from existing silicate rocks on Mercury, or it could come from electrolysis (splitting) of the aforementioned imported water. The remaining hydrogen from the electrolysis of water could be used for Nuclear Fusion power. Nitrogen would also be needed in the atmosphere. This could come from splitting Ammonia (NH3) from Callisto, Ganymede, Saturn's clouds, Uranus, or especially Neptune. Left over hydrogen from Ammonia could also be used for Fusion.

Afterwards, massive amounts of seeds from plants are used to vegetate the new artificial world. Then, the core is dismantled to build shells at the polar regions. These shells store raw materials and other stuff. The leftover heat from the mantle helps accelerate plant growth.

Once the Globus Cassus made from Mercury is ready, people will move inside. Since people live inside, this solves the problem of the massive amount of heat Mercury receives from the Sun.