Sandia National Laboratories fired the second and final full-scale Mobile Guardian Transporter into a barrier at its rocket sled track in fall 2025, closing out a two-test qualification series for the Department of Energy's Office of Secure Transportation (OST).

The head-on crash used Nike rocket motors to propel a semitrailer loaded with mock nuclear weapons down the sled. Engineers equipped the trailer with nearly 500 data channels for acceleration, strain, force and temperature, plus about three dozen cameras. A standard sled-track test of this scale would use around 100 channels.

"This was our last opportunity to understand how the trailer performs in a crash," said Jason Berger, the program's crash test lead for the second test asset. "The results will help qualify the design, a critical step before production can begin."

The scale pushed Sandia's team to build what Berger called a temporary multi-acre facility around the sled, with a control center, data collection trailers and console trailers. The run was, according to test director James Dykes, "the largest data collection effort in the history of Sandia's rocket sled track facility."

Planning took roughly 18 months. The team built redundant pathways and backup channels so critical data would survive equipment failure. Monsoon storms flooded the track multiple times; engineers still met the test date.

What did the two tests cover?

• 2020 (Prototype 1): Side-impact crash evaluated the first test asset.
• Fall 2025 (Prototype 2): Head-on crash completed the series.

The first test examined lateral intrusion and rollover dynamics. The second test pushed restraints, trailer structure and shipping containers to their design limits, capturing data needed to qualify weapon-system transport on the new vehicle.

Who supplied hardware and funding?

Several nuclear weapons modernization and stockpile programs provided hardware, including Los Alamos and Lawrence Livermore national laboratories. The Kansas City National Security Campus's New Mexico Operations location is the production agency for the Mobile Guardian Transporter. The Office of Secure Transportation, the National Nuclear Security Administration (NNSA), and the three labs locked in funding, hardware delivery and the technical basis.

About 200 Sandia employees worked on the test. Sandia is the design agency for the transporter and the lead systems integrator for nuclear weapons programs.

What changes after the test?

Engineers now pivot to data analysis. The team will compare results against pretest predictions and refine computer models.

"We met all our testing objectives, including the speed at which the trailer crashed," Dykes said. "We're where we wanted to be with data acquisition and collection."

The Mobile Guardian Transporter team plans to use the dataset to build a modeling and simulation tool. Berger said the tool will let engineers analyze many different crash environments, assess trailer performance, and evaluate nuclear safety during transport. It is intended as the enduring assessment platform for the program.

Why the breadth of instrumentation matters

Sandia ran about 500 channels where 100 would normally count as complex. The extra density was deliberate: weapon systems from multiple stockpile programs ride the same trailer, and each must be qualified for its own crash environment.

"Nuclear deterrence programs need to assess safe and secure transportation for each weapon type," said Tara Olivier, a Sandia senior manager in nuclear deterrence. "Gathering the environmental data from the crash will help qualify those systems on the Mobile Guardian Transporter."

What comes next for the program?

Data analysis will run alongside final design decisions. The Kansas City National Security Campus's New Mexico Operations location will use the test results to inform production of the new transporter fleet. Labs Director Laura McGill framed the test in deterrence terms: "Safe and secure transport is a key element of maintaining a credible deterrent."

With the qualification series closed, the program's risk profile shifts from physical testing to model validation and manufacturing readiness for the next-generation fleet that will carry weapons and other sensitive materials for OST.