SPMT: Providing transport to SLS core stages

by Chris Bergin

NASA teams are finalizing the details on the Self Propelled Module Transporter (SPMT) that will allow for Space Launch System Structural Test Articles (STAs) and the Integrated Core Stage (ICS) to depart the Michoud Assembly Facility (MAF) en route to shipping to various NASA hubs, including the Kennedy Space Center (KSC).


SPMT’s are used all around the world, usually involving modules of four, five or six axle lines.

The hardware modules can be connected to the multi-wheel transporters to transport a load that is too big or too heavy for a truck or low-loader. This also allows for the payload to be rotated and moved sideways during transit.

Z3Versions of the SPMT were recently used to transport the “Dog Houses” out of the VAB’s High Bay 3 (HB-3) during the ongoing transition of the building for its multi-user role with SLS and potential commercial tenants.

Endeavour’s final journey to her California Science Center retirement home also involved riding atop of a SPMT, allowing for her to be negotiated through a local neighborhood and its tight streets, packed out with locals taking a glimpse of the famous spacecraft.

The transportation of large elements of hardware – born inside the famous New Orleans facility – has an interesting history, ranging back to the Saturn stages that launched from Florida during the 1960s and 1970s.

Z8However, the transportation of the large Saturn stages out of Michoud, ahead of their flagship missions, is only documented in a handful of photographs.

While the transport was a simple set of wheeled trailers, they were pulled by US Army WWII M26A1 Tank Transporter – an unarmored, soft top version of the vehicle – to a small dock housing the barge that would take the stages to the launch site.

The vehicle – nick named the Dragon Wagon – would then pull the stage out on the barge, into the Kennedy Space Center’s Vehicle Assembly Building (VAB), where it was attached to the crane in the Transfer Aisle, ahead of being hoisted over into the High Bay for integration processing.

When NASA moved into the Space Shuttle Program (SSP), a simplified – yet highly specific – transporter was used to transfer the External Tanks from Michoud to KSC.

The delivery process began when the tank – mounted on its wheeled transport platform – was towed by tractor the one-mile distance from Michoud’s tank assembly building to the dock where a 225-foot-long Pegasus barge awaited.

Once secured, the barge was towed by one of two ships – the Liberty Star or the Freedom Star – ships that NASA also used to retrieve the Solid Rocket Boosters following a launch.

The ship and barge would leave the Mississippi River Delta, making course across the Gulf of Mexico heading for the southern tip of Florida.

After passing through the Florida Keys, the duo travelled up the Atlantic coast to Port Canaveral – the harbor for Kennedy Space Center.

The tugboats then took control of the barge once it approached Kennedy, towing it up the Banana River to the Turn Basin at KSC, where the transporter would carry the tank to the VAB’s Transfer Aisle for mating operations in the High Bay with the assembled SRBs on the Mobile Launch Platform.

NASA’s new monster rocket will follow this heritage, with the SLS Core Stages set to be manufactured at Michoud ahead of their own sea journey – mainly to KSC once the launch campaigns pick up.

The A-1 Test Stand with SLS coreTwo other destinations are on tap as part of the development and testing program, namely the Marshall Space Flight Center and Stennis Space Flight Center – the latter of which will be deeply involved in engine testing with the RS-25s on the integrated core stage.

As part of the path towards core stages leaving Michoud, NASA teams have been finalizing a design requirement – ahead of it being sent out as part of a procurement document – on the transporters that will carry the cores before and after their shipping.

Known as the SLS Self Propelled Module Transporter (SPMT), a total of four transporters will be required for the SLS Program.

Z15“The SLS GSE (Ground Support Equipment) Systems Engineering team have developed a procurement specification for acquiring four outside Self Propelled Modular Transporters (SPMTs),” noted L2 information.

“A team consisting of representatives from the Stages Element Office, Mission Operations, Structural and Mechanical Design; Safety and Mission Assurance and Transportation Office was assembled with responsibilities to generate requirements for the procurement of these SPMTs.”

The SPMTs will be required no later than 2015, as stages start to make their journeys in preparation for the 2017 debut flight of the SLS during Exploration Mission -1 (EM-1).

Z7Prior to that, testing at Marshall will involve the the Structural Test Articles (STAs), while Stennis will host the first Integrated Core Stage (ICS).

“The SPMTs will be used to move the Structural Test Articles (STAs) and the Integrated Core Stage (ICS) from MAF to the other NASA centers where testing and launch services will be provided. The STAs will need the SPMTs to assist in the move from MAF to MSFC,” added the information.

“The SPMTS will be used to move the ICS from MAF to Stennis for engine testing. The SPMTs will also be used to move the ICS once it arrives at KSC.”

An additional set of requirements list the need for the SPMT to be able to travel at up to three miles per hour and be able to – when SPMT modules are grouped together – carry up to 600,000lbs.

The transporters will be tested at the NASA Test Load Facility (TLF) at MAF.

(Images: Via L2 content from L2’s SLS specific L2 section, which includes, presentations, videos, graphics and internal – interactive with actual SLS engineers – updates on the SLS and HLV, available on no other site. Other images via NASA)

(L2 is – as it has been for the past several years – providing full exclusive SLS  and Exploration Planning coverage.  To join L2, click here: http://www.nasaspaceflight.com/l2/)

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