Authorities on Wednesday night discovered the trailer at a car wash near Hutchins. University of Minnesota research associate Asad Aboobaker says the trailer's seal was not broken.
Hutchins police did not immediately return a message Thursday, but previously said the driver said the rig was stolen Monday from a Dallas motel.
The cargo was bound for the Columbia Scientific Balloon Facility near Palestine (PAL'-uhs-steen), about 80 miles southeast of Dallas, but never arrived Monday. The equipment is meant for use in a science project in Antarctica.
Further details on the driver were not immediately available. A message left with Minneapolis-based Copeland Trucking was not immediately returned Thursday.