What Are Self-Propelled Modular Transporters (SPMTs)?

Self-Propelled Modular Transporters (SPMTs) are massive, multi-axle platform vehicles used to transport the heaviest and largest objects in the world—such as Starship and Super Heavy Booster, bridge sections, oil refinery columns, ships, and space shuttle components—that are far too large for standard trucks. Unlike traditional heavy haulage that relies on a semi-tractor pulling a trailer, SPMTs are entirely self-contained and controlled remotely.

Core Capabilities

• Modularity: They operate like giant industrial building blocks. Individual SPMT modules (typically with 4 or 6 axle lines each) can be physically linked side-by-side or end-to-end to create a platform of virtually any size, capable of carrying well over 15,000 tons.
• Self-Propulsion: They do not need a truck to pull them. They are powered by a Power Pack Unit (PPU) attached to the end of the modules, which houses a diesel engine that provides hydraulic power to the drive motors on the wheels.
• Omnidirectional Steering: Each wheel axle is independently computer-controlled and can rotate 360 degrees. This allows the massive platform to move forward, backward, sideways (crab steer), diagonally, or spin perfectly in place like a carousel.
• Hydraulic Suspension: The bed of the transporter can be raised or lowered. This allows the SPMT to drive under a load sitting on temporary supports, raise its suspension to lift the load off the supports, transport it, and lower it precisely onto its final foundation without needing an intermediary crane.