For the trial, rockets accelerated a semitrailer loaded with mock nuclear weapons along Sandia’s sled track before it struck a barrier. Engineers instrumented the vehicle with nearly 500 data channels measuring acceleration, strain, force and temperature, while about three dozen cameras recorded the impact.
The test completed a full-scale crash programme that began with a side-impact evaluation of the first Mobile Guardian Transporter prototype in 2020. Sandia said the latest event provides engineers with a more complete picture of how the trailer, cargo restraints and weapon shipping containers perform under severe accident conditions.
“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 latest test took only moments to execute but required about a year and a half of preparation. Sandia described it as the largest data-collection effort in the history of its rocket sled track facility, requiring a temporary multi-acre test site with a control centre, data-collection trailers and console facilities.
“This was a very heavily instrumented test and the overall scope of it was very large,” said James Dykes, the test director. “These kinds of large-scale, high-consequence tests don’t come along very often because of the complexity.”
Several U.S. nuclear weapons modernisation and stockpile programmes supplied hardware representing different weapon types that the Mobile Guardian Transporter may eventually carry. Los Alamos and Lawrence Livermore national laboratories were among the organisations providing equipment for the evaluation.
“Nuclear deterrence programs need to assess safe and secure transportation for each weapon type,” said Tara Olivier, a Sandia senior manager working in nuclear deterrence. “Gathering the environmental data from the crash will help qualify those systems on the Mobile Guardian Transporter.”
Sandia said the test met all of its objectives, including the required impact speed and data-acquisition targets. Engineers are now comparing the results with pre-test predictions and refining computer models that will be used to examine a much wider range of potential crash environments.
“Using the crash test data, we’ll build a modeling and simulation tool that will allow us to analyze many different crash environments,” Berger said. “The modeling and simulation tool will be our enduring tool to assess trailer performance, assess safety of our weapons systems during transport, and assess nuclear safety of the trailer.”
About 200 Sandia employees worked on the test alongside the Office of Secure Transportation, National Nuclear Security Administration and other laboratories across the U.S. nuclear security enterprise. “Safe and secure transport is a key element of maintaining a credible deterrent,” Sandia Labs Director Laura McGill said.
The Mobile Guardian Transporter is designed to replace the current Safeguards Transporter as the latest generation of specialised vehicles for secure movement of nuclear weapons and fissile materials. Beyond accident protection, the system is intended to safeguard its cargo during other emergencies while supporting the Office of Secure Transportation’s highly secured convoy operations.
The programme was launched in 2016 as the third generation of dedicated U.S. secure nuclear transport systems, following the Safe Secure Transport developed in the 1970s and the Safeguards Transporter introduced in the 1990s. The Kansas City National Security Campus’s New Mexico Operations is the production agency for the new transporter, with the crash-test results set to inform final design decisions and future fleet production.
