Titan Fleet Yards

The Reusable Nuclear Shuttle concept was a real world concept from around 1969/70 for a nuclear powered spacecraft that could be used to ferry payloads to lunar or geosynchronous orbits. It was even contemplated that configurations of multiple such shuttles could be used to go to Mars. What makes it interesting to me is that it could be conceived as a predecessor to the DY-100 transports.

Reusable Nuclear Shuttle

The Reusable Nuclear Shuttle, part of an ambitious overall concept called the Integrated Program, would have been launched by a variation of the Saturn V rockets that launched the Apollo missions. You can read more about the Integrated Program and the Nuclear Shuttle at Beyond Apollo:

• Integrated Program Plan (1969)
• Nuclear Flight System Definition studies (1971)

In the Star Trek universe, these concepts could be the perfect way to make sense of the DY-100 spacecraft of the 1990s. The Reusable Nuclear Shuttle could evolve into a system that has its payload arranged along its centerline, similar to the DY-100. As you can see below, removing the submarine-like sail from a DY-100 already makes it look much more like a believable 1990s spacecraft. Whatever the sail actually does (docking, cooling?), there may have been variants that did not have it.

Early space transportation