Space Bridge

Space Bridges (スペースブリッジ, Supēsu Burijji) are a form of interplanetary transport, allowing Transformers to move from one planet to another almost instantaneously without the need for a spacecraft, via a "short-cut" through the extradimensional realm of transwarp space. Early models required machinery at both ends of the bridge to open a stable dimensional portal, but later iterations of the technology consisted only of a generator at the departure point, which could open bridges to the desired location without the need of a receiver at the other end. Centuries into the future, space bridges have evolved into Transwarp Drive, allowing vessels to generate their own portals wherever required.

Biography
The bridge requires a mechanism at both ends in order to successfully open a portal traversing the interdimensional void: On Cybertron, this mechanism is a fixture in Shockwave's command center, where it takes the form of an elevator-like cylindrical tube, the top of which projects outside of the center's dome, while on Earth, it takes the form of a circular metal ring. Due to the constant relative motion of Earth and Cybertron to one another, however, the optimum location on Earth for the space bridge to open constantly changes, requiring the Decepticons to construct new bridges regularly.

The bridge's operation commences with the ring projecting beams of energy that converge at an apex in the sky above its center, opening a dimensional portal. The bridge's contents (usually along with a great deal of rock and detritus) are then drawn into the portal, which closes with a large discharge of energy. On the Cybertronic end, the travelers arrival is marked by a beam or gusher of energy arriving from deep space.

In early uses of the space bridge, the dimensional portal could only remain open and stable for a maximum of 11 minutes. Early space bridge travel likewise proved somewhat unstable, and required the use of a small vehicle to safely transport any cargo. The vehicle was rolled into the ring on a railed structure, and then had to be piloted along "a beam of light". Some Decepticons displayed pronounced horror at being chosen for this unenviable task, as not staying on the light beam would cause the pilot and cargo to "cease to exist".

Past
The space bridge was apparently first conceived by Shockwave in 1984, as a means of transport back to Cybertron for the Decepticons stranded on Earth, and to allow them to ferry energon cubes to revitalize the planet.