Supramundane and Suprastellar Worlds
Shells suspended above planets or stars by mass-stream technology
Within the Terragen Sphere supramundane planets (also known as supra-planetary habitats and/or shells) can trace their origins back to the Supra-Jupiter concept of the information age visionary Paul Birch. Although others may also have had the idea it was Birch's work that survived the nanoswarms. Because of his early advocacy of Mass Stream Technology he is well written of, even in current engineering texts.
As part of a general discussion on terraforming projects in the Sol System the gas giant Jupiter was examined by Birch. Birch knew that Jupiter's surface ( if you could call it a 'surface') gravity was far too high for habitation by humans. So he proposed creating a new surface above Jupiter at 100,000 km from Jupiter's center of mass, where gravity is felt at Earth standard. This surface would be suspended using so-called Mass Stram Technology.
Mass Stream Technology uses mass particle beams which encircle the planet or star to support structures above it; by exerting thrust magnetically against these beams (known as dynamic orbital rings), suborbital structures can be suspended at any height. Dynamic compression members and dynamic orbital rings using mass stream technology would be configured into a framework around the planet which would support platforms, which could in turn support a large biosphere. Individual platforms could then be extended into bands which could later be widened into a complete shell.
In most ways the details of the biospherics are similar to those of other space habitats. Airwalls at the edges of the platforms keep the biosphere in place until the shell is completed and supporting the shell with orbital rings avoids the need for 'unobtainium'. Jupiter, with a mass of 317 Earths, would have a shell (at 1 standard gravity) with 317 Earths surface area. [a simple calculation shows this ratio holds true for any supra-planetary shell - an 'underbody' with a mass of 100 Earths would have a shell (at 1 standard gravity) with 100 Earths surface area, etc.]
Although Supra-Jupiter would remain only a proposal, other supramundane planets would be built in the millennia to come. As Birch pointed out a supramundane planet could be built around any heavenly body, however if a standard gravity was required on the shell then the underbody needed to have greater than standard gravity at its surface, also if the underbody in question is hotter than a small red dwarf star then active cooling systems will be needed.
Suprastellar shells, dynamically supported shells around stars, invariably use power-collection equipment on the inner surface, and are therefore counted among the many classes of Dyson Swarm or Dyson Sphere which have been constructed in the Terragen Sphere.