Comics
In the Transformers comic, the Decepticon warlord Straxus commissions the creation of the Space Bridge so that his warriors can join with their brothers on Earth.
Although the Space Bridge's precise method of operation is never explained, it appears in the comic as two halves of a large, metallic bridge, with some sort of subspace tunnel connecting them. The Decepticons (or their prisoners) walk onto one end of the bridge on one planet, and when they reach its middle point, the subspace tunnel teleports them onto the opposite end on another planet.
According to early issues of the comic, the Space Bridge was originally constructed from the body of an imprisoned neutral scientist named Spanner. After a failed attempt by Blaster to put him out of his misery, his final fate is left unknown.
Though tactically vital to collaboration between the Decepticon forces on the two planets, the Space Bridge is also a heavy liability. It is difficult to defend against sabotage, and very hazardous to use; any combatant falling into the space on either side of the bridge is immediately destroyed. While in the throes of insanity, Megatron even uses his fusion cannon to blast the bridge in an apparent suicide bid.
The Space Bridge is eventually discarded in favour of the Trans-Time Dimensional Portal, a far safer, more efficient method of travel.
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